Bloop Questions & Answers ... 
By MIke Sandlin                 Last Edit:
May 15, 2017

This is a listing of selected questions that I have been asked about the Bloop and motorfloaters in general, along with my answers. I do appreciate comments, new questions,  and corrections. Please be sure to read the website first and then tell about what you have read on the website (!), otherwise I won't know what you already know (this also tells me if my written materials  are unclear or incomplete). My e-mail address is "m--sandlin" followed by "@sbcglobal.net ".

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May 15, 2017..."What do you think about putting floats (30-35 pounds each, I weigh 150) on bloop?"

My Response: (See question of Dec. 29, 2014, for previous discussion). As I have said before, weight additions will require new calculations, and I don't know much about floats. If floats require a critical water speed to step up to the planing mode during a takeoff run, then that might be a problem for an airplane that has a very low ground/water speed in a headwind. I don't see any paramotors taking off on floats.


April 16, 2017....."I've been reading that in most biplanes the fwd wing (usually upper) stalls slightly before the rearward wing. I'm wondering if you have incorporated this on the Bloop design. Also have you considered a folding wing version?"

My Response: I assume this biplane rigging is for stall recovery, unless it is some performance enhancement that I don't know about. For stall recovery safety I seen no problem (except some slight performance loss) with rigging a slightly higher angle of attack in the forward wing, so the forward wing stalls first and the nose drops, a kind of automatic response in the right direction. However, it probably wouldn't be noticed on a motorfloater which hardly stalls anyway. I'm not going to do it, I don't think the effect is worth the more complex construction.
I don't plan a folding wing version of the Bloop, I have already built the removable outer wing panel versions (Bloops 3 and 4) which allow for getting through gates or into buildings if really necessary.  I am not impressed with folding wings, it's too much effort to assemble or dismantle the plane for short flights, I don't know any power pilots who do it. The trikes in the hangars at my airport almost never come out and fly. For frequent and convenient flying I use a fully assembled aircraft which can be quickly rolled out and flown, then quickly put back in the hangar or tie down spot.


March 17, 2017...."...one of your stated goals is crash protection of the pilot. Looks like the reduced structure of the new nose section might offer less protection...?"

My Response: The reduced nose structure of the Bloop 4 probably does offer less protection than the deep trusswork under the pilot, but I think the trade off (for structural simplicity and side area reduction) is a good one. The old truss nose section was carried over from the Goat and Bug airchair gliders, where the nose section was on the ground and was the pilot's only protection from below. Now the pilot is way up in the air on collapsible landing gear, and that serves a similar purpose with substantially increased clearance from the ground.
My crash safety goal is to convert tragedy into comedy so minor crashes can become part of the flying adventure. Flying slower and getting the pilot farther back into the structure are still part of motorfloater development.

February 25, 2017...."

My Response: I use a High Energy Sports Quantum 440 hang gliding parachute (The 440 means 440 pounds maximum suspended weight, my gross weight in the Bloop is about 390 pounds). My Bloop parachute is just my old hang gliding chest pack chute, the same one I used on the airchairs, a modern but ordinary chute and deployment bag. I suppose any normal hang glider chute would be adequate, sized for a single pilot in a hang glider at the right body weight, as mine was. The chute will have a specified maximum suspended weight limit, it would be best not to exceed that, a bigger parachute should be okay if needed. My system has not been tested or used, so I don't know of any special requirements other than to modify a cover bag so the chute can be removed by an upward pull (see the drawing B4N16). The descent rate under canopy might be fast because the Bloop's weight is greater than that of a hang glider, but this is assumed to be offset by the greater impact protection offered by the pilot being belted into an extended, collapsible airframe. My system is unusual because it is attached so as to lower the plane tail or wing first, destroying the plane on impact but presumably sheltering the pilot.

All the Bloop 4 tubes are sized to be no longer than 8 feet so they can readily be shipped by parcel post truck for home delivery, for the convenience of the builder. Using full length upper spar tubes without the splice is not a problem if you can get the tubes.

Please post questions to the "motorfloaters" Yahoo Group so we can make this site a functional means of exchanging ideas. I tend to get the same questions over and over, and a forum group might have some new answers.

Buy the fabric you think you need (yards on a roll), get more if necessary, and try to have some left over for repairs. I usually cut my own tapes. And for fabric work, here is the biggest, most cosmic and colossal hint of all: get a scissors sharpener.


December 9, 2016...."Was that roll out without brakes [ landing in video "Bloop 4 Flies Slow #1]?  Such a low energy arrival.  Can you strap on some weight to normalize the pilot to 220lbs and see how she flies?"
My Response: In the video I landed without brakes until the tail went down, the Bloop has no main wheel brakes or air brakes. When the tail went down, the tail skid acted as a ground brake, but it was not very effective because there is not much weight on it when the pilot is on board. (The nose wheel has a friction brake (always on), but I did not stop on the nose so it was not used). There was some headwind, which you can see on the windsock as I fly the landing pattern. . Ground roll is pretty short, and it was even shorter back when I was using the big beach tires, which were draggy and allowed slower dives down to the runway.

One pilot weighing more than 200 pounds has flown the Bloop, with no special problems, so I am going to leave it at that until some heavy pilot builds a bloop and tells all.


September 20, 2016...." while I am a big fan of 2 axis control, what is the big harm in ailerons for the Bloop and half the dihedral? in the videos you can certainly see the yaw/roll coupling, but it looked like it would have a lower pucker factor if both yaw and roll were present?  And, when do you think we will see the shock absorbing landing gear struts on the '4?"

My Response: In two axis control, both yaw and roll are "present", but the roll is not directly controlled and is achieved with less adverse yaw than with ailerons. I can't see any harm in ailerons (excluding locking into spins, which might not be possible in a Bloop) but if they slowed down the turns I wouldn't use them much. Turning mainly means getting the nose around, and a skidding turn with a big rudder might be faster.
 
It may seem that a simplified control system is not a good match with a light wing loading, and that wind turbulence could be a threat to safety by rolling the plane, but there has been a lot of this kind of flying (especially in hang gliders) and it has been found to be acceptable at low speeds.

More sensitive controls might not contribute to safety, anyway. Recreational and trainer type aircraft have controls which are less sensitive than aerobatic or high performance planes, and are considered safer for it, because the less sensitive controls make them easier to fly and less problematic for unskillful pilots. I have been tuning the Bloop 4 to be less roll responsive for exactly those reasons, but if someone wanted quicker rolls they could tune for that.

I plan to test some elastic landing gear for the Bloop 4 soon, but there are many unknowns and there may be a series of versions before success, if ever. It will be complex and require more maintenance, etc., so it must be clearly better than the existing system, which looks pretty good right now. In years of operation, pushing the system to find the limits, the only damage to the Bloop has been the several times I have wiped out the landing gear, that's why I want more wheel banging ability.


September 13, 2016...."...And Bloop4 -wheel. This is due to the complexity of the take-off or landing ? Design for Bloop- 1 is not comfortable (not practical) ? Construction of Bloop-4 is right evolution?"
My Response: Yes, Bloop-4 is right evolution. All these nose skids and wheels work, but  I like the braking wheel (the one I have now) the most  as a nose skid because it is smooth in operation and simple to build.

".... I understand that when a large installation «angle of the cross –wing...aircraft will be very stable in calm weather and possible difficulties with the wind . In next developments of his biplane , you dont use the ailerons . This is due to the complexity of the construction assembly ?I want to do airplane with the ailerons . I think that my desire may be is a mistake?"
My Response:  I think I have demonstrated that the Bloop does not need ailerons, but I suppose you can try them if you want.
A larger polyhedral angle of the wings would probably make the Bloop roll faster in response to yaw, but this might be more sensitive than I would want. Not having the ailerons reduces the complexity of the control system by half, and makes the plane easier to fly. I have not found any real difficulties with the wind when proper two axis procedures are followed (mainly, keep the nose low when rolling on the ground). Strong winds can be turbulent and can be uncomfortable in a motorfloater.

"I think that is very reliable Bloop-1 design , the wing has a large margin of safety ...It is very important to build SAFETY plane. What advice do you have for the aircraft manufacturing for 2 people ? On what to pay special attention to?"
My Response: The Bloop 1 had two rudders but did not steer well at low speeds on the ground. The later Bloops had one center line rudder and steered well at all speeds because the rudder was in the prop wash.
For legal reasons I cannot build a two seat plane, but if I did it would be side by side, not tandem, for better communication. For a greater load, the structure should be reviewed for greater strength (the Bloop structure is untested). Special attention should be paid to wing loading, I would add wing area to keep the wing loading light, which is what this design is all about. A light wing loading will allow slow flight, which is important to safe operation and crash safety, since most crashes occur at about flight speed.

August 10, 2016...."If I were to begin building the center sections of the wings will I need to make modifications later if I decide to build a B4?"
My Response: I'm flying the B4 with the B3 wing now. The B4 will (probably) have the lower end of the inner front flying wires set two inches farther out to get greater clearance from the seat edges. I don't know what this will mean to other builders.

August 10, 2016...."Do you start by tying one end of the line to one of the links then just tie off the one end around the bundle? Your drawing "B3A8" depicts how it should look when it is done but not how it looks to start."
My Response: This is about how to secure the multi-line lashings used to tension the low load cables. I do it differently almost every time I tie one off, I haven't found one way that is better than the others. I just make sure to use a series of simple square knots to secure the line ends so that the lashings will stay tight and in place. It's nothing fancy.

August 10, 2016...."...about the "clown" donut wheels....Can they be had in any other colors?...Are they heavier or lighter than the "Fat Bike" wheels? ...where do they come from? Do they have ...bearings or bushings?"
My Response: Search the Web for "beach wheels" and you will find the current Bloop wheels. They are used for boat carts, mainly, and the big ones come with bearings . The big wheels used for kite buggies are similar but black. I need to get through one bad thorn season before I can really accept these wheels as a practical option, but they are wonderful for soft landings and rolling on rough fields. The clown wheels are probably lighter than some of the larger volume fat BMX tires that I have used.


July 15, 2016......"How does she fly with the stick hard forward? Any real dive or just a parachute down? What do you estimate max descent rate at?"
… do you have any Guesstimates as to the wing section weights? "

Response:  I can't really give you any numbers, but I can make some comments. I have not flown with the stick far forward, that would be aerobatic and I'll let someone else try that. In a nose down attitude there is not much speed gain, so I can just aim at the runway threshold to correct a high approach. I don't know the descent rate or airspeed. My guess at total wing weight would be about 100 lbs. depending on how much silvering is used (a lot for outside tie down).


June 13, 2016....."I plan ...flying below 500 ft AGL to stay out of the way of fast moving traffic.  My understanding is that chutes can take 1500 feet to deploy, depending on how fast you are going, and I suspect I will be going much slower than average chute users.  At some point doesn't it just become extra weight?"

Response:  Parachutes are often deployed from ordinary airspeeds and altitudes. One friend of mine deployed due to loss of visibility close to mountains, another because he was stuck in a shallow turn, another because he wanted a big drogue chute for a perilous landing. None of these required fast openings or much altitude. Bloop speeds are not slow compared to average users, like hang gliders and paragliders, but opening speed is not the big thing, reliability is the big thing. When flying higher than a training hill I fly with a total recovery parachute system because it is easy to have along and I might find it useful.
Flying high is a safety trade off, faster traffic is bad but more altitude for emergencies is good.
Typically I fly about a thousand feet or higher above the ground, higher than necessary, because some emergency landing areas are better than others.


February 7, 2016...is there any changes from Bloop 1-2-3 if you were to build a Bloop-4 knowing all the older attributes you might reincorporate in to a new Bloop-4.
On Bloop-3 was the horizontal stabilizer put on the top instead of the middle due to center would require stiffing/at a weak point in the middle. I thought I read that part of the Bloop-3 modification was to get better control from the vertical and horizontal stabilizer at low speed from prop thrust, what I was thinking the middle would provide better control than on top...

Response: The horizontal tail plane is high for structural reasons and to stay above the prop wash. There has been no need to change the horizontal tail parts, they work fine, I want them in smooth air. Putting the rudder in the prop wash was only to get better steering at the slowest speeds on the ground, otherwise it just makes flying rougher, beats up the structure, and adds drag.

There are no  Bloop 3 improvements I can think of. The raised landing gear and rectilinear rudder that were recently added don't  amount to anything of basic importance.

I have in mind a "Plan B" program, which  involves paramotor pilots making a simple transition to airplanes by flying a "paramotor mimic" , a motorfloater ultralight airplane that flies like a paramotor but without the canopy issues. This would be an alternative to "Plan A", the conventional approach, where you join a flying club, receive a year of instruction, get a license, fly heavy airplanes, then maybe come back to ultralights eventually.
A good paramotor mimic airplane would have the same airspeeds, motor, and seating as a paramotor, as well as two axis turn control. It is possible to continue the Bloop program and build a bigger wing so as to fly slower, and this might make it a better "paramotor mimic" for Plan B development, but I don't have any intention to do that yet.


January 15, 2016...."I like the center section concept how wide is it and how long does it take to right the 4 outer panels?  Is it practical to do for a days flight?"

Response: This has to mean Bloop 3, since that is the Bloop with the center section. The dimensional answers will be on the drawings (see the drawings in the  Picasa Albums for quick answers). This is all about Bloop 3 transport and assembly, presumably on a trailer but maybe just in and out of a small  hangar. I don't know much about quick motorfloater transport, I haven't done any, someone else will have to give it a try. I operate from a tie down at a rural airport because I want to fly often, and that setup involves a low burden operation.


January 14, 2016.... " [building] This engine mount is really testing my patience.  I don't think there is a part I haven't made twice and many of them 3 or more times."

Response: Sorry about that, but the Bloop engine mount required a lot of test fitting, the dimensions given are measured afterward and would not be exactly the same twice in a row. I just kept the basic goals in mind (like, get the engine pointing mostly straight backwards) and tried to build using a sequence that allowed match fitting or at least was tolerant of the bigger holes and other deviations that may result from drilling in place. Inexact construction can be adequate and functional, especially since much of the design does allow shaping late in the fabrication (for instance, the cable rigging establishes the wing geometry, and many parts can be attached with spacers to adjust their positions).


December 18, 2015....In response to an email, I changed the nose attachment eyebolt specification for all the Bloops and the Pig. The drawings now clearly call for the 1/4 inch shank eyebolt, which was correctly shown but had the wrong name in the text. This change is not critical, the stronger bolt will just resist bending better than the small one and will be less likely to bend out of alignment after some high load, like a hard landing. The drawings revised are P1W15, B1W14, B2W14, and B3 W15. This can happen when you use old drawings to create new ones, you carry along an early error until it gets noticed. This is one type of template error. The first drawings to be updated will always be the online visible drawings in my Picasa album. When you look at drawings check the online versions and be sure the date on the drawing is the same, otherwise there has been a change.

(December 2, 2015)"...come China to visit me at Kunming during March and April...can help me to built Bloops 3..." 

Response: I thank you for your generous offer, but I will not be traveling anytime soon, I have much to do here at home. I hope you will take advantage of all the resources available for Bloop builders,  especially, make contact with the Yahoo Airchair Group, and the Motorfloater group to get advice from other prospective builders. My ambition is to provide useful Bloop  support on my website, so I want people to go there first and then tell me what is wrong, unclear, or inadequate, so I can correct it. This is "information support" that can be accessed by many users, not as good now as person-to person contact, but which could be massively effective in the long run.
Motorfloaters might provide basic airplane flying and building to individuals and clubs everywhere, especially in those places where beginning is otherwise difficult, perhaps including China.


(October 30, 2015)  "... the books say that a biplane does not generate twice as much lift as a monoplane of equal dimensions- I have seen estimates from 20% more than a monoplane to as much as 50% more, with a large gap and stagger. Yet when wing loading is mentioned, all the area is used for calculating it, as if it were indeed generating twice as much lift, rather than 120% of the projected monoplane. What am I missing here?" 

Response: Good question! When looking at wing loading I treat the upper and lower wings as equal in lift to the equivalent monoplane wing of the same span, but that's simplistic and not really true, the biplane wings will interfere with each other and suffer a loss of lift  performance. I have not seen a biplane handicap formula, but it might be worth considering when comparing biplanes and monoplanes for equivalent wing loadings.

I don't consider special biplane effects much. I do not even discount the lower wing for having a messy upper surface, even though I am sitting in front of it, which shows how crudely I am calculating.

A simplistic approach seems to be serving me well enough, so perhaps at very low speeds the interference between the wings is less than at high speeds. Or, maybe monoplanes really are a better deal than I give them credit for.

Getting only fractional effectiveness out of the lower wing is discouraging, but it is still just a part of the trade off. I get a light, stiff structure from the equal chord box kite, and the parts commonality makes the construction easier. My Bug airchair was a sesquiplane, and that setup seemed to be a good compromise between biplane and monoplane.

A monoplane would probably be the best approach to a highly efficient airplane because it would have the best chance of using a small motor. Let's define the efficiency of a recreational airplane as fuel consumption, effectively "gallons of gasoline per hour" used according to some recreational flight profile, just slow flying with no concern for high speeds, long range, or great climb rate. If you then wanted to make the world's most efficient practical recreational airplane, you could build a monoplane motorfloater, put a modern 20 horsepower paramotor engine on it, and you would pretty much be there. Now you have to demonstrate that the plane is practical and satisfying while using less than a gallon of gas per hour. Of course there would  be many users of this small aero engine who are already flying at this high efficiency, but they are not in airplanes and are not enjoying the benefits of a rigid wing with a tail.


(September 23, 2015).."... the gap cover between the horizontal stabilizer/ elevator and the vertical stabilizer/ rudder.  In order to allow for disassembly can I assume you only attached the flap to the forward pieces (stablizers) then coated them with the same sequence of coverings or do polybrush the flap the both pieces and forever marry them together at this point."

Response: Gap covers are not considered removable, but they can be cut or stripped off as required.


(September 19, 2015)..."...Bloop 2.  I've covered the tail section and am ready to apply poly brush/spray/tone.  Did you apply tape over the ribs in the tail or just around the edges.  Did you melt drain holes for condensed water in any of the pieces?  Obviously I plan to stitch the wing ribs and reinforce them.  Did the wings get drain holes?"

Response: Tapes are applied everywhere the fabric goes from supported to unsupported. That includes the edges of the ribs. The idea is to double the thickness of the fabric where it goes over an edge and might see high stress. Drain holes are good, you can punch them in the middle of an applied grommet or melt holes through taped areas (double thickness). My plane will sometimes drain from the tails and wings when I rotate it after rain, so I don't think it's just condensation in there. I don't have many formal drain holes, there are other openings that do most of the draining.


(April 1, 2015)..."Will the Bloop 2, without an engine, be able to function as a glider?"

Response: The Pig is like the Bloop and is a training glider (see the training hill video, "Pig Rolling Launch", on Youtube), and the later Bloop designs would probably work just as well as simple gliders after the engine is removed and the pilot seat is moved for balance. I think that a lightly loaded, two axis controlled glider is the best for novice airchair training because it is easy to fly and provides a lot of crash safety. As many instructors will tell you, it is important that a new student be able to fly, at least a little, on the first day. The three axis airchairs like the Goat are not practical for early training because there are too many things happening at once, and training becomes a series of failed flights that really beats up the airframe.


(March 24, 2015)..."I noticed your Bloop 2 Drawings use no welding, as you say in your Drawing group A. However, I have the equipment to heliarc weld aluminum. Could I replace some of the bolted connections with welds or would this compromise the structural integrity?

Response: I won't comment on someone else's design, but for my own purposes I like garage technology, with no welding, molding, or machining. I can build, modify, or repair my airframe without specialized parts or equipment. Other methods can certainly be strong, perhaps lighter, and might have less of the Frankenstein look, but the nuts and bolts are very practical.



(March 24, 2015)..."do you know of anyone who has actually built a Bloop II (or any of your aircraft for that matter) using the drawings?"

Response: I don't know of any other motorfloaters like mine that are flying. I consider the Bloop to be a very different type of airplane that pilots are going to have to think about for a couple of years, then maybe.

There are numerous airchair gliders similar to my Goat that have been built and flown , and I assume they looked at my drawings.



(March 20, 2015)... "I am attempting to build an ultralight aircraft and found your plane and plans very promising. In regards to your Bloop II, do you have any suggestions/ plans for the order of construction? what would I want to build first?"

Response: Something small, I suppose, how about a tailskid or the rudder pedals? The rudder has been a popular start choice for homebuilders, it involves a little of everything and is not big, it also looks good when painted and propped up on the garage wall.


January 29, 2015...."... Is 15 hp sufficient with red drive . Could the ribs be made with foam with fir or spruce caps and instead of is wing spackle to make the wing struts for aerodynamic use balsa like instructed then cover with dacron or cover of choice ..."

Response:   It would be interesting to see how smaller engines perform on a Bloop-like motorfloater. In Bloop 2 I get 25 hp. at 8000 rpm. (manufacturer data), and I seem to need about 6000 rpm. to sustain altitude. Assuming power to be proportional to engine speed (rpm.), this says I need about 18 or 19 horsepower to keep flying. A good indicator of being underpowered might be failure to climb above ground effect (about one wingspan high). Trying to climb more in an underpowered condition such as this might put a motorfloater "behind the power curve", losing altitude at full throttle, settling back down onto the runway (been there, done that). I have seen one pilot fly away while stuck at ground effect altitude at full power, out over the bushes, but I don't remember him getting far. The first turn would probably be the end of the flight. Of course, the reduction ratio and propeller twist must be matched to paramotor/Bloop airspeed, or the available power will not be effectively used, which is one reason I fly with a well developed paramotor engine system. I suspect that any modern paramotor system could power the Bloop, but the real question might be "are you satisfied with it?".
I won't comment on the other design changes, I am not there to see them and cannot properly make judgements.


Response:  I'm not sure what would make a good float plane. The Bloop airframe is stiff and has a good selection of hard points underneath, so I suppose floats could be attached. Low flying speed might be a good thing, for operating in a wide margin of wave conditions without getting pounded (?), but low power is probably not good. I just don't know the basics of this, neither the flying nor the cycle of operation.


November 18, 2014 "... what are the advantages of Bloop2 compared to Skypup and vice-versa?

In other words: how would you compare both?"

Response:  The Sky Pup and the Bloop are both home built ultralights in the 200 pound class (about as light as airplanes get) with small engines and rudder/elevator control systems, so I'll make some comparisons.

The Sky Pup is popular and has been flown for more than 30 years. I have never seen or flown one, but I know one pilot who has, and he liked it. He did say, however, that even an average size pilot may be a little cramped in the small cockpit. The Pup might be one of the few planes that can fly with a small enough engine to use less gas per hour than the Bloop. One source says it has no substantial stall or spin hazards. The controls used are the same as Bloop 2 (fore and aft stick for elevator, foot pedals for the rudder).

The Bloop is all about having a light wing loading, resulting in slow, easy, and comfortable flight. The Pup wing loading is greater (more conventional) and it is faster. The Pup pilot is enclosed, mostly to shield the pilot from the prop wash, I suppose, whereas the Bloop has the propeller in the back, letting me fly in the open with a good field of vision and lots of room. In the Bloop I probably have better pilot protection in a crash due to the extended collapsible structure, including the box kite wing and landing gear. The wide spread of the Bloop landing gear is good for keeping the wings level on the ground, whereas the Sky Pup typically has a narrower wheel track and looks like it might not tolerate winds as well.


September 22, 2014 "...how easily [could] the Bloop 2 could be modified to be disassembled and transported on a truck like you have shown with the Pig on top of the small Nissan? I saw the CAD images on how the Pig’s wings unstack and the struts rotate into place but have a hard time understanding exactly how the mechanics all work out. Do you have any additional pictures of the mechanics of the rigging and struts when assembling the Pig? Also, is there any twist in the Bloop2 wings for tip stall prevention or are the speeds so low, wing loading so high [not?], and wings so square that this is really not a concern? How safely do you feel the Bloop 2 handles windy or gusty conditions with the 2 axis control? ...It would be really nice if it could be folded up and assembled /disassembled easily. Based on your Pig experiences, how long would it take to set the aircraft up? Do you have to adjust the tension cables between the bi plane wings or do they keep their adjustment once initially set up?
We would love to see some of your airplanes in person..."

Response: The Pig glider was transported on top of a pickup truck but was not easy to set up like the other airchairs, it was a prototype and I wanted to get it flying and work out the quick setup later. The Pig Page photos show a lot, and the wing panels are so light that setup of the main wing box was not tricky as long as the wind was light. I think the two axis control, two wheels, and light wing loading is still the right setup for a primary glider trainer (see the video), although much of its structure and mechanics have been improved upon by the Bloop 2 and upcoming Bloop 3.

Slight wing washout is imposed just to preclude wash in, it doesn't matter much at this low wing loading, there is no great stall hazard. The Pig suffered from hard landings because of the high sink rate of its parachute mode, which is what you mostly get instead of a nose drop stall when the stick is held full back (you can see some of this on the Bloop 1 video when it suddenly drops to a landing). This is the "stop and drop" routine familiar to hang gliders and canopy fliers. One reason for bicycle wheels on the Pig and motorfloaters is they can be sacrificial, when they break you can order new wheels instead of repairing the airframe.

The real issue in gusty conditions is the light wing loading, you need special ground handling procedures for that, mainly to keep the nose down into the wind, like a hang glider. The two axis procedures, which also require a nose down position when on the ground (to prevent a wing tip from being lifted by a cross wind) must also be followed. The Bloop 2 is a motorfloater flying at an airfield, so I am spoiled and won't fly in difficult conditions, regardless of the control system. Flying the two axis system is very ordinary, I can't say that I have encountered any special limitations.

It probably took half an hour for me to setup the Pig. The cable tensioning is in the landing cables only and was done by multi-lacing, which I think was just loosened, not undone, for transport. The Bloop 3 is intended to have removable outer wing panels with a free standing center section which can be rolled onto a trailer without disassembly, perhaps a better method.

Sorry, not much to see yet, except at the local club fly-in once a year in August (see San Diego Ultralight Association). Floyd Fronius has been flying Goat airchair soaring demonstrations at the Experimental Soaring Association Western Workshop in Tehachapi, California, on the Labor Day weekends.



August 8, 2014     "...are there any items that have shown to be worthy of note in the maintenance realm? ...have been any repeatable conditions that would be worthy of marked attention after some number of hours usage?...components that had a fairly limited life span and would need to be carefully inspected for cracks. I rarely flew more than 10 hours in any one stretch without some piece of structure failing."

Response: The Bloop and the airchairs are pretty robust, without much unexpected maintenance. Tire deflation due to thorns was pretty well eliminated by using sealing slime in the tubes (which some pilots will not do because they fear a rotating imbalance). The control lines still stretch a little, even when using the Vectran/Dyneema mixed lines, but they are easy to access and adjust (all the Bloop control lines are out in the open and near center line). The plastic seat frame is broken and loose, it will eventually need a replacement or more re-enforcing. I have removed three bird nests from on top of the engine. I thought the rigging lashings (tensioners) would require adjustment, but I haven't needed to touch them since they went on two years ago. The bungee cords including the stick trim have required tightening on occasion, they weaken and stretch with time under tension. I expect wheel spoke damage, eventually, due to heavy loading and shock applied to my bicycle wheels. The only cracks and dents I've seen are a result of my dubious craftsmanship, not usage.


July 2, 2014 .....Would it be possible to mount a 200cc motorbike or quadbike engine, instead of the 185 ?

Response: I suppose you could use almost any small engine, but the paramotor power package has been developed, tested, and comes with the reduction drive system and propeller already on it, so I don't see how you're going to beat it with a custom engine. Will you have confidence in an experimental engine? Will engine adaptation slow down the project? How will you know that you are getting all the power you should? An off the shelf system will take care of all that.


March 18, 2014 ....."In your Q&A page I see you addressed pilot weight by saying you don't really wish to address heavier pilots, but....Is there any conceivable way to accommodate a pilot 6'6" and of 250# or more in a Bloop? It seems this realm of flight is limited to folks of your stature, while folks like me can only dream of gliding....?

Response: Nothing has really changed, I know that the airchairs and motorfloaters are attractive to big, heavy pilots in part because there is lots of room out in the open when the constraints of a small cockpit are removed. Preserving a light wing loading (or at least having a high lift wing) for slow flight is still critical, however, both for enjoyable flight characteristics and safety (i.e., the reduction of low speed flying hazards and the possibility of slow crash speeds). The only new and hopeful thing I can add is perhaps to point out that the biplane configuration does readily allow the increase of wing area without much additional weight or increase in lateral dimensions.
Note that the Bloop 2 is about 78 pounds under the Part 103 weight limit (when the allowance for the total recovery system is added in). I don't know of any other ultralight airplane that is significantly under that limit.


February 23, 2014....... "Will the Bloop 3 wings have the same amount of dihedral that the Bloop 2 has?  It is hard to tell from the new pics. 
I am still determined to build a Bloop, just holding out for the Bloop 3 updates."

Response: Don't wait too long, there's never any guarantee that the next version will ever come out! I like to stimulate interest, but I don't tell all because if the Bloop 3 never flies then all that hopeful design information becomes misinformation. With a truly ambitious prototype, the first version of a part will often be reworked into something quite different, so early descriptions can be misleading. The plan is that the Bloop 3 will have some minor upgrades but will not look or fly much differently than Bloop 2. There is no sure improvement to be made by Bloop 3, it will test some new items, but Bloop 2 will probably turn out to be lighter and simpler, and might fly better (slower).

The Bloop 3 is planned to have polyhedral, created by having center wing sections that are horizontal with only the outboard panels set at an angle. The outboard wing panel angles are designed to be varied by cable adjustment to the equivalent of a 6 degree dihedral or whatever is desired.

February 7, 2014........ "At the speeds your motorfloaters fly at, have you thought of investigating the airfoils used by the Gossamer Albatross & Gossamer Condor? From what I’ve read, both are fairly stable (have minimal pitch-up) at varying angles of attack, have the absolute minimum power requirements, and are thick enough for a respectable full-depth spar.......Which might lead to a monoplane bloop. A monoplane would be less draggy, which could translate into a smaller, lighter power plant for the same performance. They fit in well at the required speed range, too. They’re not flat-bottomed, which might pose some stowage problems on your trailer, but nothing insurmountable! "

Response: Right now I'm steering the Bloop design in the direction of flying like a paramotor, to create an interesting airplane as well as one that might be a quick transition for paramotor pilots. I want a light and lifty wing with no sudden low speed hazards. It must fly slow, essentially a one speed aircraft.
The LISSAMAN 7769 (Condors) and Wortmann FX 63-137 (ULF) airfoils could no doubt be used for motorfloaters, but it would be a lot of extra work, and not worth it to someone like me who doesn't even use ribs that reach the bottom wing surface. The expected benefits might not be seen on the roughly built wings of basic homebuilts. Less drag makes landings harder, but I do like the idea of going easier on the engine or using a smaller one. Stowing the wing panels is an issue, and it is one of the reasons that the Bloop3 wings have become thinner and flatter than the Bloop 2 wings.

"Pitch-up" I take to mean a nose up pitching moment coefficient that increases at higher angles of attack, an instability that requires a big horizontal tail surface. A motorfloater with a big horizontal tail will not have much trouble with this, I can select a high lift airfoil without much concern about pitch. Generating trim forces does create drag, of course, and the use of stable airfoils (perhaps semi-symmetric) will reduce this. I liked the flat bottom wings (which were close to semi-symmetric but actually did have some rear end camber) on the Bloop 1 and may go back to them sometime.
 

A wing area greater than 180 square feet makes for a large and awkward single seat monoplane, whereas a biplane can have an even larger wing area within compact lateral dimensions. The box kite structure of the biplane also provides a great deal of primary strength and torsional stiffness with minimal weight.



January 18, 2014........."
My question is if you know the best L/D and the speed for that L/D plus the weight of the aircraft;

can you figure the horsepower required to keep it in level flight?"

Answer: Numbers are in short supply, except that I fly at about 24 mph., gross weight about 375 lbs., climb at maybe 160 fpm., and have a 25 hp. engine, which with this prop is supposed to produce about 170 lbs. thrust. At 5800 rpm., I am slowly descending. I think I could use a smaller engine, maybe 20 hp., and still get by.


January 2, 2014........."how are your research work?....wish you a Happy and fortunate New Year 2014"

Answer:  What I am doing right now is trying to build an airplane that flies like a paramotor. This might provide easy access to airplane flying for
a growing pool of paramotor pilots. The Bloop 2, which I have been flying this year, is already behaving about the way it should.
The Bloop motorfloater flies like a paramotor:
  1. same airspeeds
  2. same pilot position, view, instrumentation, and controls
  3. same engine
The Bloop motorfloater might improve on a paramotor:
  1. Wheels, no running
  2. Rigid wings, no canopy
  3. Fixed tail planes, more stable flight
  4. More crash protection
I plan for Bloop 3 to have two axis control by hand (control wheel) instead of foot pedals, to be more like  a paramotor. We will see!

December 21, 2013...... "Please talk about your flight head gear."

Answer:
My radio head gear is an ordinary modern aircraft headset with a push to talk button on one ear shell. This headset serves to shield me from engine noise as well as to allow radio talk, which is required at my airport but not everywhere. I can't really hear the transmissions of the
other pilots very well with the engine running above idle, I just try to catch the key words. I have to let go of the control stick to transmit (one hand to push the button, one hand to shield the microphone), but I can still steer with my feet.
The headset is plugged into an ordinary portable Icom aircraft radio set which I carry in a shoulder harness (
made for paragliding), so it stays on me and is usable when I am out of the aircraft. I cannot easily change frequency in the air (and haven't tried yet). 

The radio needs to be taken home on occasion for battery charging.
My helmet is an old rock climbing item from my hang gliding days. I cut big gaps in the sides so I can wear the headset over it.

October 14, 2013...... "you seem to leave the Bloop, at least in the open...For me it is sort of a painfull thing to do so, not only due to UV...Dust, water, wind, two legged gremlins...
...about the covering material... plane flew ...The covering was while and a fabric that looked like some seed bags...Flat large strands crossing in a 90 degree weave, like dacron...But quite ugly, unpainted...He said it was a greenhouse material from Israel that outlasted dacron against UV and it was even stronger in strenght... far cheaper than Dacron..."

Answer:   Oh, yes,! It is for some pilots unbearable to leave their darling airplanes, especially their hand crafted show pieces, out in the weather. I use an outside tie down with covers over the engine and seat, but I pay a price in exposure damage and needed maintenance. In return I have a simple setup that allows me to fly fast and tie down fast, without hangar maintenance. These trade-offs have to be judged by individuals, but I prefer the low burden system. The fewer requirements you establish, the more likely you are to get your feet off the ground.

I get just as tired as anybody of brushing dope on fabric, it's a drag, and I welcome the pre-finished films and fabrics that may eventually put an end to this, but for now the proven dope and fabric systems are my preference. I'm glad to see that these new covering materials are being tried, and I will keep an eye on them, but I try not to be distracted by developing  things that are not on my main line of interest, which is "flying tailed rigid wings at a light wing loading".

October 8, 2013..."goat and bloop 1,2,3.....would be extremely kind of u to give the dimensions of drafts in METRIC SYSTEM [ mm,cm] also if possible...this fraction system is brain sweating.bloop 2...
i am thinking of adding additional fixed slats and vortelators will it give more short
takeoff and landing characteristics in restricted Landing zone.bloop 2
how about going fibreglass instead of fabric will it be strong ,tough, lasting, cheap and
light??? if fibreglass will the draft need to be changed modified etc ??? drawbacks any?"

Answer:
Fractional dimensions are not a good system, and metric dimensions are the right way to go, but the system I am in is slow to change. I use metric units where possible, but the availability of hardware and materials dictates my use of the old english units for now.
Conversion of Goat or Bloop drawings to the metric system would be a great thing, but it is not trivial, it is nothing like a mere metric description of an assembly. Should a 1/4 inch bolt (4.8 mm) be replaced by a 4mm bolt or a 6mm bolt? An engineering judgment is required for the selection of almost every material and part. This is a big job and probably should be part of a complete re-design and a new prototype flying project.

The Bloop landing is four times longer than the takeoff. I use 200 feet of ground roll to land as opposed to 50 feet for takeoff. It is the landing that is driving the field length requirement (at my body weight , at least). When I consider smaller fields I think about airbrakes, a better ground brake, and a smaller (lighter) engine, not lift devices. Overall I am satisfied with the Bloop short field performance as it is.

Tube and fabric still looks like the best primary structure to me. Is there any composite ultralight wing that is "strong, tough, lasting, cheap and light"? Not yet, I think. Of course I do use composite construction for a lot of my secondary structure already.




August 25, 2013...  "...the Goat ,do you think the goat could equipped with electric motor? I like the Bloop but I think the design a little complicated for a newbie like me. I recently make an electric motor for paramotor and could achieve a few minutes take off speed about 20km per hour at 20hp like electric equivalent at 9,000watt."

Answer: When the Bloop was underpowered, it would get up about one wingspan (using energy stored as extra speed and then pulling up through the headwind gradient) and then settle back down onto the runway, fun but not impressive. Your 9 kilowatts (12 horsepower) may not be enough to climb, nobody uses any less than that for anything that I know of, and they don't carry batteries. Of course you have to get the propeller right, but I will leave that to you and the other motor developers. The Aviad Zigolo is like a motor Goat, but it uses 25 horsepower, as does the Bloop. With less than half that power, I suspect you would not get up for long.


July 15, 2013...   "the way forward... (1) engine cost reduction (2) construction simplification, lower parts count. (3) easy dismantling

Answer:
The subjects introduced here are good ones and deserve a response, although they do not directly involve my idea of the basic motorfloater theme, which is to fly really slow due to a very light wing loading, so as to fly differently from other airplanes.
1) Paramotor engines are getting better but not cheaper. The small, adapted utility engines of the past are being replaced by purpose built aero engines because the paramotor engine market is big enough to do that. I don't expect much change in this, especially if these new engines are more reliable and the major complaint against ultralights is that the engines are "unreliable".
2) Construction simplification in Bloop terms means garage technology (hacksaw, hand held drill, etc) and parts commonality (for instance, all the wing spar tubes are the same size, which is not exactly what you would get from structural considerations). Reducing the parts count is a good thing but not high priority compared to having airframes that can be quickly repaired in primitive conditions (the hangar) by non-specialists (the pilot and friends). I don't recall hearing much about reducing the number of rivets in a sheet metal airplane as a "parts count" issue, I think because rivets are simple, common parts and easily obtained, and many Bloop parts are somewhat like that. I doubt that advanced versions of the Bloop will have many fewer parts.
3) Easy dismantling is an important part of making a practical ultralight, and the Bloop is not there yet because only prototypes have been made, concentrating on flight results instead of lowering the burdens of operation and ownership. My concept for the Bloop is to build an eight foot wide permanently assembled center section and have the outer wing panels detach from that, so all the engine and flight controls remain connected while the plane can be rolled into a garage or onto a trailer. 

July 2, 2013    "The bloop how does it do with the vibration frome the engine?, does the airfame suffer fome that?, or no so much ( loose or weared parts, holes out of shape)
I'm asking this qouestions because i whant to make an ideea how long the glider will last, before any major coponents neede to be changed, sort of overhoul or mainenace stuff. "

Answer:  I have 53 hours on my engine with no airframe wear seen. Of course the skid plates wear from ground contact, and the plastic seat frame is disintegrating, but those are minor items. The airchair gliders, with similar airframes, don't show any wear either, as far as I know. Repairs have been from fabric exposed to sunlight or bashing of wheels and landing gear struts (hard landings on rough ground).

These little paramotor engines have pure neoprene mounting spools (there is no bolt through the middle of the isolating spool, the engine is attached by rubber only) and this seems to provide good vibration blockage.


July 2, 2013   "I downloaded the plans for this great machine .
...Are any of the brackets standard off the shelf items?
...I need some kind of idea how much time to build and approximate cost.
You wouldn't possibly have cut lists would you? ...
I downloaded as a GIF and can't print from it." 

Answer: There probably are commercial brackets that could be used on the Bloop, but I have not used them so I'm not the authority here. Water jet cutting of flat parts is what we really want, but I'm not personally likely to do it. "Somebody" should put all the dozens of flat brackets on one drawing, throw in a few extra parts, have a water cutting done, evaluate the product, and then post whatever final  file is used as input to that job so we can all have it done easily.

Build time and approximate cost, for Bloop 1 at least, have been discussed on this list already. If people want to go into this, they first have to tell me what they have already read, and refer to that, or I will be answering this same question over and over. I don't blame anyone if they don't like the answer, it is inexact, but there actually is no exact answer that would be meaningful.

I think a "cut list" is a table of materials in the sizes in which they are ordered, a "bill of materials". "Somebody" could do this from the drawings and post it, but I have not. 

While "somebody" is at it, it would also be nice to have a discussion forum and posting location for motorfloaters. This should be separate from the Airchair Forum, because we are talking about motor flying, not gliders. 

There should not be a problem printing bitmaps, unless printing full scale parts is desired, which will best be done using the CAD (computer assisted design) format download with CAD software.

For liability reasons I do not use the word plans, I provide drawings which are a description of what I have done, not a recipe for making anything. 

April 11, 2013 "...your height and weight?
I’m 6’ 1”, 210 lbs …..
Moving the seat back seems problematic as does moving the pedals forward. ???
I was thinking of the Hirth F-33 which is several pounds heavier (weight behind the CG) than the Moster 185 and perhaps a small ballast at the tail?"

Answer: Getting good balance will always be an issue on a plane where the pilot is half the weight and he is not located at the center of mass. It would be good to have a movable seat, and some tail balast is not out of the question, either (but move the pilot back first just for elegance). I moved the pilot forward by extending the whole nose section at one time. I have moved both the seat and foot pedals at various times. 

The Bloop weight and balance check (see drawings B2A2 & B2A3) involves setting the loaded plane level on the wheels and then requiring that the nose be slightly heavy. The wheels are located at the presumed and expected center of lift, however, true confession: judging from the engine and tail plane angles, I probably located the wheels too far forward and I am flying nose heavy (inefficient but not dangerous). If I were ambitious, I might move the pilot and wheels a few inches back, set the engine level, and decrease the tail plane angle a few degrees. This is not likely to happen because I am having too much fun with a flying airplane, I don't want to ground it, and aerodynamic efficiency is not a big deal for someone who wants to fly slow.

I weigh about 150 lbs., not tall or short, but I don't want to go into the heavy pilot issue. I can't say if you will be satisfied with a heavier loaded airplane, since the whole point of the Bloop is to fly at as low a wing loading as possible.

Flying with a heavier engine probably means you will need a longer runway. It's the landing that determines the minimum size of your operating area, and with more weight, you will come down faster and with more energy, with only a little bit more drag at idle, so you will probably cover a greater distance over the ground before stopping than before. This suggests that there may be an optimal size engine for the Bloop, a size where the takeoff and landing both call for the same length runway. 

If I were going to add another mechanical system to the Bloop, it wouldn't be ailerons or wheel brakes, or even a priming system for inflight engine restart, it would instead be an airbrake, because that would give the airplane the biggest boost in operational capability.

March 7, 2013  "Very inspiring craft. 4 cycle would be nice. What does the current motor prop
weigh and how much trust does it produce?  What Prop is on it? 48x?"

Answer: Get a 4 cycle engine if you want one, they are available in the same size and are now commonly used on paramotors and trikes. I don't know about the propellers, weights, and thrust (although "trust" is also a big issue), look at the manufacturer's website for some of that. One of the reasons I use an "off the shelf" power pack is so that I don't have to specify things like the prop, I just buy the patramotor unit, bolt it on, and fire it up.

February 20, 2013  "The Vittorazi Moster 185 is a VERY expensive engine for a poor highschool student and I was
wondering if you knew and could reference me to equivalent engines to the Moster 185 that would be (less expensive)."

Answer: I'm not an engine expert, I just like the paramotor engines because they are small and come with a propeller already set up to fly slow. Any paramotor engine should work for the Bloop, I suppose, but smaller engines would have to tried out by someone to see if they can give satisfaction.  There may be used engines and high time engines available for pilots who will accept the risks and penalties, but you'll have to look around for those. 

December 8, 2012  "Do you have a known distance for normal-relaxed take-off roll and landing space
used by your bloop 2?"
Answer: No, I can't specify that, you'll have to look at the videos, get some experience, and make your own judgements. Runway length is not enough, for safety you need clear approaches and clearance to both sides.


December 4, 2012  "... Bloop 1 had the wings staggered by about 12-inches. It looks like in the picture of the Bloop 2 that there is no stagger now. If so, has that been done to simplify the construction for the central rudder / tail assembly?"
Answer: Bloop1 and Pig had a 12" stagger (upper wing 12" farther forward than the lower wing), mainly to position the wing lift to allow the pilot to sit in front of the lower wing. Bloop 2 has an 8" stagger for similar reasons. This also allows positioning of the propeller over the lower wing, so the noise of the engine and propeller is reflected upward, reducing noise at ground level.

December 3, 2012 "... BLOOP #1 had the box kite twin boom so if an engine was installed it would prevent turbulence problems on the tail assembly.  Why did you drop it for the single rudder/boom of BLOOP #2? "
Answer: The rudders outside the propwash created less drag (in theory) and got beat up less, but the central rudder in the wash has more control authority because of the high speed air being constantly pushed onto it. The central rudder is a good thing at low speeds on the ground, so you can stay on the runway while starting or stopping. In the air I don't feel any difference, but I now favor the single rudder for practical reasons on the ground.

November 4, 2012 " ... I have read Robert Gus Gissings website and downloaded his Excel
spreadsheet of parts for the Bloop1."

Answer: This looks good, it's the kind of thing we need to invent the "bill of materials" kit. Imagine complete drawings available on the internet, along with a "bill of materials" that includes three or four purchase lists. Each purchase list is specific to a commercial source, you can just mail it to them and say "send it", and the trucks deliver almost everything you need to your house. In addition there will be active internet support, such as builders groups, forums, individuals, etc. The advantage of this over a commercial kit is that no one has to be in, or stay in, business. The disadvantage is that there won't be any fully committed individual or central source of complete materials or information.

"I've also downloaded your AutoCAD file for the Bloop1 and am anxiously waiting for the Bloop2 drawings."
Answer: It's easy for me just to fly and fool around, so drawing progress is slow. The drawings might not be posted this year, but they are still in the plan. 

"...200 (lbs.) ... Do you think moving the tail feathers back a little further would help to balance my 
weight in the Bloop2 and then we could 'add' a little ballast to the nose when my buddy flies it? "

Answer: I do not give advice on other people's designs or modifications for liability reasons. I'm the only person who has flown the Bloop 2, so I haven't yet dealt with the probem of different pilot weights other than to specify a weight and balance method. Other planes have had this same issue, of course. 

"Where exactly is the CG located for you in the Bloop2?"
Answer: The wheels are located at the presumed center of lift, 29% of mean wing chord. The flight center of gravity is established by balancing the plane just a little forward of that, for stability and stall recovery (so there is no exact center of gravity). 
The high lift wings were initially requiring a lot of back stick, so the presumed center of pressure may not be correct, but I accepted it as close enough and adjusted the horizontal stabilizer to neutralize the elevator in level flight. The trim without stick pressure is now quite comfortable. The pitch angle at which the engine is mounted is also part of this trimming issue.

"I really liked your idea for making removable wing ends for storage/transport...but that photo and comment seems to
be missing now...?"

Answer: My Bloop News page moves on, and ideas for new planes come and go, but the storage/transport 
version is still my basic concept for Bloop 3. It seems important for practical reasons, and for access to 
motorfloater ownership. No work has been done on
any new Bloop, and of course it may not happen at all. I don't
talk much about new versions to avoid misinformation about aircraft that may never exist.

"I note that you said that the Bloop1 flew only about 15 hours...since you did not emphasize drilling the holes with precision, and
actually a little over-sized for ease of assembly with the bolts, did you notice any elongation in the holes upon dis-assembly"

Answer: The Bloop 1 design flew perhaps 15 hours, but it used the Pig glider airframe, which had endured plenty     of impact, so I'm not sure what the Bloop 1 hours mean. Crash damage on the Pig has included some hole elongation, but only after the tubes have been mangled. Hole enlargement has not been an issue on undamaged hardware.

September 21, 2012 "...I was wondering how the new airfoil compares to the original in the case of thermal soaring. I have to believe that many who follow your activities are not interested in XC, just love the ride up. A compact, self launching UL with the ability to climb, and the beauty of a bi-wing!..."
Answer: I commented on thermal climbing in April, 2012 (see below), and it applies to Bloop 2 as well. Bloop 2 is a high drag, "flaps always down" motorfloater, a slow and easy flier that can dive to a precise landing without much floating down the runway. Bloop 1 had more normal airplane characteristics, probably had a lower sink rate in idle, and would probably make a better motorglider, even just for climbing. With anything at this wing loading (less than 2 pounds per square foot) you can probably just park it in the lift and go up, but I don't know what the best combination of qualities would be for doing that. Paramotors and powered harness hang gliders are already doing some of this, so they should know the most about it. My primary interest in the Bloop is not as a motorglider but as an alternative type of basic airplane for local recreational flying.

July 11, 2012  " Do you plan to publish mods to the plans to include your Bloop 2?" 
Answer: I intend to post a set of Bloop2 drawings when the aircraft has flown a while and all the changes have been made. These drawings might be out this year, or maybe by spring. These are drawings, not plans, they are documentation of what I built, not intended to be instructions of any kind. I will post a single three view drawing, showing the basic dimensions, soon.

May 2, 2012 "...my questions are not resolved by any thing I've read on your web site or the discussion group stuff. Specically concerning pilot weights wing loadings and maximun/gross numbers. I ask because I am 6 foot 5; acordingly weighted, approximately 275 plus not fat but big!!...have you investigated this region of bloops potential?"  
Answer: Down through the years the heavy pilot question keeps coming back. I don't have any new answers. To get the benefits of light wing loading for a pilot 100 pounds heavier than average the wing must be made bigger, and I doubt that this will be done by anyone who is not himself heavy. If there were a two place airchair or motorfloater, a heavy pilot might fly that, as a heavy hang glider pilot will sometimes fly a wing built for two place hang gliding.

April 19, 2012  "...Ultralight airplane engine and reduction drive ... to see what you think of this type of engine for the bloop1..."
 Answer: I'm not an expert on engines, so I don't comment on other people's choices except in general terms. I use a 25 horsepower paramotor engine, an "off the shelf" unit, complete with reduction drive and propeller, developed to work well at the speeds at which I fly. Modern paramotor engines typically have efficient mufflers, good noise reduction, effective vibration isolation, and easy pull rope starting. They are light in weight, compact, and have low fuel consumption. A paramotor engine has an absolute weight limit because the paramotor pilot has to be able to pick it up and run with it, and they have a market big enough to support engine development, so this is where the high quality small airplane engines are found.
I'm trying to push the "reset button" for small, light airplanes and engines. The Bloop is intended to be like a flying motor scooter, not a speed machine. Typical "ultralight" airplane engines, as used by light sport airplanes, are big and heavy, not much smaller than about 40 horsepower, too much for me.

"Have you tried using the Bloop as a self launching glider and doing some soaring  after launching? If not, would the changes to the design be too great to consider building such an airplane?"
I have flown the Bloop as a motor glider, and it does what you would expect. It climbs well in lift but does not glide well between thermals. So, a motorfloater can do its climbing in thermals and then cruise under moderate power. This is not the traditional motor glider practice, but it is a good way for a motorfloater to minimize fuel consumption and engine usage. On a mid day flight with a small engine, thermalling could become the obvious thing to do, the fast and easy way to get altitude.
 
"Is the new higher [lift] airfoil a published design or is it something that you drew up yourself?"
The airfoil I am now constructing on the Bloop2 motorfloater is a variation of the one I used on the Bug and Goat airchairs, my own version of a double surface, flex wing, hang glider airfoil. This is not a formally defined or tested airfoil as far as I know. I like this hang glider type of airfoil because it has been demonstrated to work well at my airspeeds, has undergone many generations of development and testing, and is well suited for adaptation to the rough structure of my quickly built tube and cable wings.
Why has so little analytical attention been given to hang glider airfoils? This is a mystery to me, considering that this is the practical and proven airfoil of choice for hundreds of flights made every day.


March 24, 2012  
"I am living in a... hilly part of France with hardly any space to build a proper airstrip. Mine is situated on top of a hill and has the size and appearance (from the air) of a small World War -2 aircraft carrier, which... cannot ...... be pointed into the wind. Missing the "deck" (treshold) can give big trouble. So, for safe sidewind landings... I think...ailerons "

 Answer: I'm glad you like the Bloop, and I think something like it should be fun to fly from a little hilltop airstrip. I suppose you can put ailerons on a Bloop type airplane and use them to slip, but that is not really the solution to a short runway. I would probably add airbrakes or a drogue chute for regular tight landings because for the same level of complexity those would be more effective in allowing steep descent without airspeed gain, and in reducing ground roll. Also, unlike slipping, you can use airbrakes all the way down the runway, along with the ground brake. I am not impressed with the energy loss accomplished by slipping, not after flying with effective high drag devices.
I think all of this applies to cross winds as well as otherwise.
Two axis planes are generally held to be limited to small cross winds only, but I suspect that that is a landing gear design problem rather than an inherent limitation. With my "nose low" ground roll, I have not yet encountered any cross wind limits.



Feb. 29, 2012  "What are the expected cruise/stall speeds for the Bloop 2?"
Answer: I have no estimated numbers, but I'll take some measurements when I get flying, as I did with Bloop1. For a motorfloater the stall speed will depend a lot on the weight of the pilot, of course, so that will be quoted, also.  
 
FAR Part 103 requires that a motorized ultralight must be able to fly at less than about 28 mph. (stall speed not to exceed 24 knots), which implies a kind of pilot weight limit. Presumably, an ultralight with an average weight pilot and a marginally fast stall speed cannot legally be flown as an ultralight by a heavier pilot because the stall speed will be excessively fast. The Bloop stall speed should be quite slow, well below the limit, with an average pilot.

Response recieved:  "Part 103.1(4) “Has a power-off stall speed which does not exceed 24 knots calibrated airspeed.”  Advisory Circular AC 103-7 # 21, further defines the requirement to calculated (or demonstrated) with a pilot wt. of 170 lbs and a full tank of fuel (5 gal @ 6 lbs/gal)."
My response: This answers the question. There is no implied weight limit, the stall speed limit refers to a specified loaded condition. I now see that Part 103 does not stand alone, it must be taken together with whatever Advisory Circulars have been issued as clarifications or definitions. This also provides a useful design model for an average piolt weight. (However, since my gas tank only holds 2.5 gallons, I presume my pilot can be 15 pounds heavier...?)


"The idea of $5k for a motor seems a little (no a lot) steep...something suitable out there that could be modified for a lot less.
A lightweight flat twin two stroke [engine] might be a viable candidate especially for low vibration/noise levels."
I want to work on airframes, not engines, so I look only at "off the shelf" power packs that don't require any modifications or development. There might be paramotors sitting in closets, maybe not the latest models, that would be inexpensive, and any popular paramotor system should be able to power a motorfloater.
"... is there any way I could get to fly a Bloop 1?"
Not even I can fly a Bloop1 since I tore it down and started the re-work to the Bloop2 version. I really miss my open air local flying and I hope that the next time I build a new airplane I can keep the old one operating.

At the time I grounded the Bloop the underside fabric of the upper wing had become weak and was not airworthy, in my judgment. The upper surface wing fabric on both the upper and lower wings was fine, even though it had been outside for a year and a half, because it was well coated with protective silvering (aluminum powder in dope). There was no protection on the lower surfaces, since those were expected to be in the shade, and this worked well enough on the lower wing, but not on the upper wing, which was a surprise to me. I think the reflected sunlight, from the ground or lower wing, caused the lower surface fabric of the upper wing to deteriorate.
From now on I will apply some protective silvering to lower wing surfaces as well as upper surfaces, which is more like a conventional fabric covering job anyway.

Jan. 27, 2012    " ...wonder if adding a small wheel on the front skid to prevent wear or do you see a wear bar is better.  Also how much flight time have you put in on this airframe design?  I have been reading about the engine and wonder how are you finding it; would you change it out if you could now.
I am interested in building this since it is built around a motor and I am not a glider pilot and we do not have any great hills to glide from. "

Answer: On the Bloop Page I describe why I use a glider type landing gear, basically for safe landings in strong winds, an important issue at light wing loadings. The nose skid is reliable, fun to use, light, and simple. There may be a conventional wheel system that will work as well and not be limited to light winds, but I haven't seen it yet.

As a motorfloater I flew the Bloop1 about fifteen hours, mostly making brief flights. As a glider it did a lot of rough flights but didn't get much airtime.

The simple paramotor engine has worked well and was easy to put on the plane. An "off the shelf", integrated, flight proven, and available power pack is good for me, it allows me to concentrate my design efforts on the airframe. We might choose to use additional engine instrumentation relative to the paramotors (which is pretty basic or almost absent), or maybe we'll learn to do it their way, we'll see how it goes.
Any good paramotor engine setup should work well on the Bloop. If I were getting a new engine, I might get one of the 4 stroke paramotor engines of about the same power as I have now, just to try it out. The 4 stroke would be heavier for a given thrust, but it's supposed to be quieter, more reliable, and to use less fuel.

The great benefit of a motor plane is that it can fly out in the great flat lands where glider launches are hard to come by. Gliders appeal to me and a limited few, but most pilots want motors.

It's best when custom airplane builders build because they want to, not just to get a particular airplane. "Buy and Fly" is the best plan except for those who want to create or experiment.  I would like to see something like a commercial Bloop, but I have no plans to be involved in that. The Bloop has a conventional airframe and controls but a radically light wing loading, and unfortunately I know of nothing like it that can be purchased.

I don't know of any home building kit for a motorfloater.

The "Bill of Materials Kit" for an ultralight aircraft is possible but has not been attempted yet. Someone has to list all the required materials on a spreadsheet and organize them into three or four purchase lists addressed to particular retail vendors. Then builders can download those lists and easily order almost all of the materials and parts they need, and have them delivered by parcel truck, without the need for a kit supplier. Building support would come from the Web, from forums and from a  website dedicated to the building of that aircraft.

 
Feb. 5, 2012 "Do you see the Bloop2 being significantly different from Bloop1?"

Answer: The Bloop2 will continue along the path of the Bloop1. It will be is a motorfloater intended to explore slow flight with a simple airframe and controls, a small engine, and good pilot crash protection.
Bloop2 will
be generally similar to Bloop1, but will have a higher lift airfoil and is intended to fly slower, and hopefully it will have even more forgiving slow flight characteristics. A primary goal is to be able to hold the stick full back and just parachute down, with no stall or nose dropping. There will also be mechanical and structural differences (one central rudder instead of the two rudders, perhaps a simplified motor mount, etc.).

Feb. 6, 2012

"...specific... areas ... that you ..(could be) altering in the next generation of your design...

layout of the wing-to-fuselage sides join, The joining of the nose section to the wing leading edges by eyebolts has proven to be effective and convenient, and will be continued. Usually I avoid changing things that work well unless I'm pursuing some major design goal or addressing a specific problem that arose in flight operation.

motor placement/mount,  Again, this has worked well and I have no reason to change it, except perhaps to simplify the original design. One of the main things I learned from motorizing the Pig (Bloop1) was the acceptable diameter of the propeller (1.3 meters), and this will be part of the Bloop2 design.

pilot hight location relative to the planes of lift, The pilot should sit high enough to be protected in a crash (and to feel confident of that protection), but he should be low enough to get his feet on the ground so as to be able to push up the nose for takeoff or to turn the plane around (in place) on the runway. The curerent position works for me.

modified airfoil, Yes, a higher lift airfoil is planned, to get more of the benefits of slow flight:  the experience of open air flying, comfort, low fuel consumption, crash safety, and the oportunity to make gross low airspeed mistakes without severe penalties.

improved control surfaces response and resultant stick/pedal loading...No, there's not much call for change here, control loads are not much of an issue at low speeds. A rudder in the propwash is planned to improve the very low speed ground control, that's all.

body section change from your proven box design (spray foam/aluminum hybrid, different fuselage skin approach). The nose section structure is not a complete braced truss (the top is not cross braced), and thus is not very stiff in twisting. This was okay for airchairs but the motorfloater has a much deeper nose section with the skid  lower down, so the twisting due to ground contact was excessive and required the installation of an extra set of forward sweep cables. I like this setup and will retain it for Bloop2, but certainly other structures are possible.

...what other design changes/challenges have you arrived at? Transportability and quick dissassembly for storage are worthy goals, but slow flight comes first, then we will see.

"...from a ...design perspective is surviving a slow-speed emergency water landing, without irrecoverable damage to the aircraft, feasible?" Let's call this a crash, in water or elsewhere. The first rule in a crash situation is: protect yourself, don't worry about  the aircraft! Destroy the plane and walk away with a smile on your face, dreaming about your next magnificent flying machine.
As for water, be careful. Deep water is one of the two big dangers (power lines are the other).


Do you think that slow motor floaters design challenges could translate well to r/c scales?  It would not be too difficult to make a small r/c
scale model aircraft modeled after yours, and to use that scale model if it proved functional, to test extreme flight characteristics of the
current Bloop, and test modifications. I have read online that designs do generally translate from larger scale to smaller scale.
Large scale remote control fliers could do all kinds of good experimental work, they could perform all sorts of tests for low speed aircraft. The results will not be rigorous but they can suggest what might be done, especially with video results to show on the web.


Feb. 14, 2012  "... i am concerned about transistioning to an aircraft without ailerons.  How different is it to fly when your stick only goes forward and back."

Answer: In theory, pilot conversion to a two axis rudder/elevator plane should be easy. You just scoot around on the airstrip doing hops and turns, knowing that all the control inputs will be the same in the air as on the ground, and when everything seems familiar, off you go. In reality, there may be a moment of, shall we say, distress, before that first turn in the air, when your previous training calls for some side stick action, but it's not gonna happen. This is when you take a deep breath and recite the mantra: "steer with your feet", and when you finally do this, the flight continues normally and all is well. Of course, you can practice steering with your feet in almost any airplane just by not using the ailerons. Turning this way may be slow and strange feeling in most airplanes, but it will demonstrate the basic method.

Feb. 23, 2012  "...the Hirth F-33 engine is the one for me [mention of local services, 1000 hours to overhaul]"

This should work, since it is well established as a paramotor and trike engine, and has support and service close at hand. It's a little more powerful than mine, and so will have a faster climb.

The engine I chose is also a paramotor setup, but it has a tuned exhaust for extra power and noise suppression,
a compression relief for easy rope pull starts (so I don't use an electric starter), a bulkhead mount (not requiring a special engine mount to get from the horizontal to the vertical mount), and it is a smaller engine so it will use less fuel, make less noise and will vibrate less, and allows me to fly at a lower wing loading.

Paramotor engines can have some drawbacks. The extensive inlet and exhaust systems are installed across the wind and may not be practical to clock forward to a less draggy position. They may not have a good place to put the EGT (exhaust gas temperature) sensor since they might not usually use them (they may use CHT, cylinder head temperature, if anything).


"drawing B1W17 has a part called, Strutt Fitting which calls for  a piece of alumimun, 1/8 x 1/2 X 2-1/4 IN long.  Now throughout your drawings the brackets and such have been 1/8th IN thick.  So does this part require 1/2 thick stock or were the measurements transposed..."

Answer: The dimensions are correct and the drawing is clear, I think.  There is a standard given in the drawings for the order of the dimensions for tubing, but I don't know of any formal standard for bar stock.


"...to build your... Bloop... how many hours do you think that I need?...what will be its probable cost without the engine and prop...?"

Answer: The cost of material will vary depending on location and builder decisions. Here in San Diego, I might pay $3k to $4k for airframe and covering materials, $5k for a new engine & prop, $800 for a new hand deployed parachute. A rocket deployed parachute (BRS type) might cost $3k if desired (the biggest cost variable is the emergency parachute, and a fancy fabric covering job might be next in cost variation after that). These are quick guesses, anybody with a spreadsheet and a willingness to look up the latest prices could do a better cost estimate than me.

The time needed is an unknown. I think I could build a motorfloater in less than a year without too much strain. I'd like to design airplanes and gliders that can be built in the cold season and flown in the next warm weather.

 

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