Motorfloater News...       
by Mike Sandlin ................................ Last edit: April 27, 2017
 





April 25, 2017.....Moving out to the runway, I push on the tailskid, rolling along.

Below left, the static balance of the Bloop allows sitting on the nose, convenient for raising or lowering the tail. A breeze will sometimes bring the tail down, bouncing on the tailskid.

Below right, I relax in my front row seat to watch airport activity.

Today I flew three patterns in mild wind conditions. With the vortex generator fins I seem to be lifting off and touching down at lower airspeed than before (no fins). I seem to notice more instability from the wheels in the cross wind than before. It may be that the lower airspeed has reduced the authority of my yaw stability and control, or perhaps the effect of the crosswind is amplified by the lower airspeed (a left crosswind becomes more left the slower you go.) Now, when I land in a crosswind, my nose is way up in the air,  and I have to do substantial rotation at low speed to get the nose down into a stable rolling attitude. The two axis procedure may have to emphasized: don't linger, set the nose low as soon as the tires are on the dirt.







 


April 25, 2017.....Fake Monoplane! This is a quick photo edit (of the next photo below) to visualize a monoplane version of the Bloop. I use photo re-work as a design tool to focus attention on what aspects of the Bloop motorfloater might be carried over into something new.


For example, this fake photo prompts me to look at the similarities and differences between my designs and others. This proposed motorfloater might be similar to a Zigolo, having about the same wing area and the same engine, but the Bloop based monoplane would have widely spaced wheels to accommodate the two axis control system. The two axis (rudder/elevator) control system is only half as complex as a three axis system (with ailerons), making it easier to build, maintain, and fly. The large diameter of the wheels also serves the goal of getting off the paved runways and back onto the grass, flying with less infrastructure.

[Please be reluctant to reproduce this photograph, or any photo of a non-existing airplane, they are fun to look at but may be misleading, mistaken for something that actually flew,]



April 24, 2017.....I flew more patterns, with maneuvers and stall tests a few days ago.
The new head phone arrangement is quite effective in lowering the noise level. Now that I can hear better I can tell how bad other people's radio calls are, lot's of static sometimes. I enjoy the quieter flying, it seems to increase my confidence in the engine and I find myself using higher throttle settings for ordinary flight. Unfortunately, while walking around on the ground I find myself being less mindful of propeller threats. My propeller is guarded from approach by the aft sweep cables but I find myself getting closer than I used to
while wearing the headgear. I guess the loudly unpleasant engine noises were keeping me away before.

I'm thinking about the biplanes of exactly 100 years ago, fighting the first great air battle in April, 1917. It must have required a self destructive amount of courage to fly then. I feel very progressive in developing airplanes in a flying environment that is just for personal satisfaction and doesn't require anything like so much courage.

My nose wheel isn't holding air anymore, too beat up I guess. For the moment I don't care, as long as it still makes a good ground brake. I make an occasional nose down stop, sometimes intentional, sometimes not. It's good to stay in practice for when braking might be needed. So far I can't recall any time when I really needed to stop short.


It seems my slow flying project is, as intended, flying slower than ever. I might someday want to build a motorfloater that flies just as slow but is lighter, so it could use a smaller engine. With a small enough engine I might get below the magic number of "one gallon of fuel per hour", a simple measure of flying efficiency. I don't know of any airplane that has reached that threshold, but a paramotor or nanolight trike flying with a small enough engine (maybe 20 horsepower) will already be there.
Slow flight will be important to anyone trying to fly with limited on board energy. Energy = Distance * Force. The energy used in flying one hour will be Energy = V (airspeed) * ((V squared) * Cd) because airspeed in MPH is the distance traveled in one hour, and the drag force is the square of the airspeed times the Cd, the drag coefficient of the airplane.
So,  Energy = V cubed * Cd.  The energy used in an hour of flight is proportional to the drag
coefficient but also proportional to the cube of the airspeed. This means good aerodynamics matter, but the big energy gains are to be made by flying slow.


 


April 19, 2017.....Today I had a few flight tests in mind for my new vortex generator fins, but I first flew a normal pattern, and started having fun, so the test program unravelled until next time.
This photo is before the flight, I think the engine is running for warm up. This is our "run-up" station for engine tests at full rpm, notice the anchor strap tied to the tail. The dry season has arrived and the wings are really dusty, though luckily that doesn't show much at this distance.
My four short flights were ordinary except for the effect of the vortex generators, which seemed to allow slower speeds, a higher angle of attack, and generally smoother operation at the slow speed end. When I bring the stick back while ground skimming the plane settles to the ground smoothly instead of dropping down, and it doesn't seem to be needing any additional runway to do it.



Ups and Downs of Bloop 2 Flying, by Glenn F., (edited by me)

I had a hard landing at Nichols field late this afternoon (April 10, '17) due to an engine out.
Apparently I didn't tighten the locking bolts enough on the redrive when I adjusted it the other day. It took a while to loosen up though. The flight was almost an hour long and pretty uneventful though it was windy aloft. At one point while I was over the BMX track heading West I throttled back and the Bloop just stood still in the air with no forward movement to speak of. I had to give it a lot of throttle to make it move towards Nichols. On the last downwind leg the engine was making a weird sound and I thought to myself "I never heard the engine make that noise before"! Then just before I turned base the engine lost complete power so I pulled off the throttle and called a mayday. Luckily I was able to glide to the field, from 700 ft. altitude. I thought the engine had seized or died while I was in the air, but after I landed I could hear the engine idling and I had to shut off the mag switch. There was smoke coming off the engine redrive it was so hot, and the belt looked like it had partly melted. the pulleys were trashed from grinding against each other. I was glad that I had stayed close to the airfield while I was flying.
Fuel was dripping on my back, my seat belt held me in my seat and I was able to exit uninjured (airplane was upside down). Several people from skydive helped me right the airplane and I was able to push it back to my hangar. There is very little damage to the airframe, mostly the collapsed left gear tore the lower wing cover fabric. The engine pulleys and the belt are trashed, but the engine and prop are o.k.
The rest of the airframe resisted getting damaged pretty well. ...it glided farther than I expected too. When the engine went out I didn't think I would make it to the airfield. I think my glide angle was too shallow though, because when I needed to flare I didn't have enough speed and the bloop stalled which caused the hard landing. The bicycle wheels did not collapse, just the two struts attached to the aft wing spar bent in half and punched through the lower wing fabric causing a rip. Bloop 2 will be down for repairs again, just when I finally got it to running good, but it shouldn't take too long to fix if I can find the time to do it.
Glenn Frehafer

I think this was just about Glenn's first long flight in the newly renovated Bloop 2, too bad about the damage, I hope it's just a matter of getting new parts. All three existing Bloops have wiped out their landing gear in their short flying careers. I want my landing gear struts to be strong enough so that upon impact the wheels are bent (they can be sacrificial because they are easy to replace) but the main wing airframe is not damaged. Maybe we are still headed towards tundra tires.



 April 11, 2017...Here are my fun fins in action! The little clear plastic fins (white in the photo) spaced out along my leading edge shell are my newly installed vortex generators, and I'm up in the air checking them out. All is well at altitude, the turns are slow and tight.
At idle power with the stick full back the nose will still dip after considerable hesitation, too bad that didn't go away, but it's happening at a very low airspeed.
Takeoff is slow, short, and smooth.
My landing approaches have been slower, so I'm spending more time in the landing pattern, maybe I need to fly closer inside to get down and clear the space for other traffic. My transition from groundskim to rolling is smoother now, I can settle down with the stick full back instead of falling through in the parachute mode.
Overall I like the generator effects, I can't say I've found any drawbacks yet.




If the aircraft red line (maximum safe airspeed) is calculated based on load relief due to stalling, then a lower stall speed will call for a reduced red line. If I consider the Bloop to have a load factor of 6 (also expressed as 6 gs) and it stalls at 20 mph., then using the stall load limiting method, I calculate a red line of 20 times the square root of 6, which is 49 mph. (I use 45 mph. as my maximum speed, I have probably not actually gone faster than 40 mph.). If I reduce my stall speed to 17 mph., my new red line is 17 times the square root of 6, 42 mph. (Notice the magnified effect, a 3 mph. reduction in stall speed resulted in a 7 mph. reduction in red line.) This means that if you lower your stall speed then you have to stay slower to maintain a given structural safety margin, so I'm not going to fly real fast with vortex generators on my wings. This is the same idea as having a reduced maximum air speed limit because your flaps are down.


 

April 10, 2017...It's a turbowing! Now my whole Bloop 4 wing, top and bottom, has these little stick on plastic vortex generator fins. I just followed the directions on where to place them, no innovations here.


The outboard fin spacing is finer than inboard, helping the wing tend to stall at the root first instead of the tip. This is desirable, it gives you a straight ahead stall instead of a wing tipping stall. It's generally thought to be faster and easier to recover from a straight ahead stall than a turning one.


The vortex generators worked pretty much as advertised. With the new generators installed I flew two test hops and then a pattern. The Bloop seems able to fly slower, and control is good at all speeds. I was concerned that I might float down the runway into the sunset, but actually I stopped in about the same distance as before. There was no "parachuting" mode, the flying was smooth right down to the runway.


I'll fly to altitude and do more testing soon.

Ready for flight testing the turbowing Bloop.

If I were buying all new equipment, I'd get an integrated crash helmet with this headgear, for enhanced flight safety, but this is the setup of the moment.





April 5, 2017....Floyd Fronius is flying with some of his soaring instruments clamped onto the nose tube. I flew with them too and made a few observations.

My nose level cruise speed was about 33 miles per hour, faster than expected, due to a high throttle setting. I flew at a comfortable height which turned out to be about 1500 feet above ground.







Bloops in a row, before the morning club meeting. They're tied down to a cable so they don't get blown away like tumbleweeds when the turboprops start up.








I made several landings with light wind from various directions. The wind on my first landing was 90 degrees from the left at about 3 miles per hour, a rare opportunity to do a two axis landing in a pure crosswind. I touched down as slow as possible, my course down the runway but my heading into the wind a little. That was good, but I was a a little late getting the nose down, the plane was tracking to the left and trying to get off the runway and perhaps the left wing lifted a bit, no smooth landing this time! I got the nose down, steered back down the runway, and was able to add power and take off again as I had intended. If I had not gotten the nose down in time I would have just had to settle for rolling out into the field and stopping, nose slightly into the wind.

Be sure to understand that the tendency while rolling in a crosswind is to be turned into the wind (not downwind) by the tracking of the tires and possibly the weather vaning of the tail. The upwind wing may start to lift if your nose is high, and that should be answered by lowering the nose to reduce the wing lift and to let the plane settle back down on its wheels. The intuitive reaction to a wing lifting on the ground is to apply rudder toward the high wing (this is what you might do in flight to level the wing)
but on the ground this is wrong, it will turn you off your intended course. The proper two axis procedure for ground rolling is to keep steering to where you want to go and lower the nose to level the wing.

The beach tires I used to fly with were better for crosswind landings and takeoffs because they did not have the stable tracking of the BMX tires I am using now. Stable tracking is usually good for runway rolling, it makes for easy steering, but when you land headed off course it works against you. The tundra type tires that are durable enough for field flying will be heavy, but they may still be an option worth trying.



March 23, 2017....This view is from a few days ago.

This flight was sunny but a little chilly, about the same as I would feel in a paramotor, but a little quieter because I'm a few feet out in front of the engine.

Recent experiments (pressing on my headphone in flight) suggest that with firm fitting headgear I could reduce engine noise and improve radio reception.

The thirty year old rock climbing helmet that I fly with has side areas cut out to accommodate my noise reducing head set, but the helmet still interferes and the earphones are not seated as close on my head as they should be. I plan to try out a cloth helmet (
like the one in a photo on this page farther down) that should allow a closer earphone fit.





March 14, 2017...
Updated Bloop 4 drawings will soon be posted, to cover the new smaller vertical stabilizer, simplified tail skid attachment, and to show just the current set of wheels. The updated drawings will have new dates (isn't that what updated means?) and the newest zip files will have the highest numbers, as always.


The Bloop 4 motorfloater flying video:

Bloop 4 Slow Flying #2


 
December 29, 2016...The Bloop 2 is coming out again. It hasn't flown high for almost two years, but it has been in a hangar and now has a new engine. A series of test hops and scoots has been flown in preparation for re-launch.



Glenn went ahead with his first high flight in his Bloop, this may be the landing. The winds were odd but the runway was soft (therefore forgiving), and the flight went pretty much as intended.



Bloop 4 is off like a rocket back on Christmas day. This looks like a high angle of attack, maybe I'm pulling up out of the wind gradient or maybe I'm focused on those trees ahead. It doesn't seem to matter whether you fly in San Diego or New York state, there will still be trees around the airport!

Photo thanks to Susan Scherer who was shooting from a nearby hilltop.




Why taxi when you can just take a nice, quiet walk?






Here I am flying at a more or less normal pitch attitude (close to having the nose level), in a slight left turn.

The paved runway can be seen running visually from my knee to my chin. I  usually land there in the lower right to upper left direction when I use the pavement, but normally I'm on the dirt strip, the edge between the light and dark fields leading up to my nose. I have to approach that strip over the scrubby hill to the right, which is actually pretty steep. My major
goal there is to come down close to the hill and use as much of the runway as I can. Without a headwind, about a third of my runway is unusable because of the need to maintain clearance from the hillside. This is why I say if I was to add more controls, it wouldn't be ailerons, it would be airbrakes, to allow steeper approaches.








October 27, 2016....Floyd Fronius is off in the Bloop 4, notice the full fuel tank and the airspeed probe mounted on the nose tube. He was flying with an instrument with flight recording abilities, so there will be numbers for those who crave them! The nose high angle is worth noting, we just fly at the angles that feel the best. Experiments at higher altitudes show that at full throttle, with the stick full back, the plane just waddles on.

The reported maximum climb rate was 400 fpm.(feet per minute), but that seemed to be with the help of air going up, the more normal climb rate was 200 fpm. I'll add on to this when I get hold of the data.

Floyd flew some roll reversals and reported that the controls are effective but the feeling is weird. I felt the same thing until I got used to it. The initial yawing is something you don't get with ailerons.


Floyd flew out to a local mountain top, looking south toward Mexico at the bottom of the canyon. The outskirts of Tijuana can be seen off to the right, this is not a clean air day down there.


I haven't been in this area, I want some place to land when the engine quits. You could land uphill in the brush, but it would probably wipe off the landing gear.



Floyd prepares for data gathering as the engine warms up (notice the spinning propeller, my paramotor power pack does not have the increasingly popular automatic clutch that would disconnect the prop at low engine speeds).
Not much warm up was needed, I had made an earlier flight into the back country to check out the new Indian reservation casino (no activity, parking lots are still dirt).

It's wonderful to be able to take action shots with people in them instead of the usual static machinery photos I have to use for my news page.

I took some takeoff shots with Floyd leaving the vicinity, walked away, turned back, and he was still there, still leaving. This is a really slow airplane!










July 13, 2016......Here's Bloop 3 warming up for yesterday's flight.

I'm not putting air in the main tires so they are getting softer on every flight. The low inflation seems to work fine. I'm not going to measure the pressure because I'm told that the sealant slime in the tire can contaminate a pressure gage.

The fittings rubbing on the top of the nose tire (for ground braking) can be seen, also the three bungee cords running back from the nose (two for the rudder pedals and one to the bottom of the elevator control stick for nose up trim).









November 8, 2015...At the local motocross track the Red Max has landed for a visit. He's flying a red Minimax with one white wing.

Room for landing is the critical factor in a tight situation like this. Maybe a good set of wheel brakes, a small motor, and a de-clutching propeller would be the right setup for this spot.







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