The Bluebird is my newest motorfloater design!

I've been flying and testing the Bluebird for more than a year. The Bluebird flies well, about the same as the biplane Bloop motorfloaters. The smaller engine is highly efficient, gentle, and relatively quiet, but climbs slowly and requires some thinking ahead. It's a slow airplane, with the pilot completely in the open, and with minimal power, a kind of flying which is very different from mainstream aviation.

The Bluebird is my current aircraft of choice for casual recreational flying.

The experience of flying this very light airplane is one of openness and slow floating over the local terrain.

This is a homebuilt airplane prototype, designed and built to evaluate the effects of very slow airplane flight, achieved by flying at a low wing loading. It also uses a very small engine, as an experiment in efficiency and other low power benefits. For lightness and simplicity, flight control is two-axis (rudder/elevator), there are no ailerons.

A private project with nothing for sale, the Bluebird operates in accordance with FAR Part 103 regulations as an ultralight vehicle, and thus neither aircraft nor pilot requires any direct official oversight or licensing. Test flights have been conducted at John Nichols Field in San Diego, California.

In the photo you see the paramotor power pack (engine and propeller together), bicycle wheels, emergency parachute, translucent fuel tank, and four point seat belts. The nose wheel is actually a skid which serves as the ground brake.

  On one test flight I weighed the fuel consumed making a 62 minute flight. My fuel consumption rate was 1.33 gallons per hour. This is about as efficient as any recreational airplane you are going to find. (My claim to fame: world's most efficient gas powered airplane? Maybe.) A light paramotor might use less gas since the Bluebird probably needs higher engine speeds just to stay in the air, so the paramotor is the most efficient flier, but it can't be considered an airplane).

The Bluebird was the only new ultralight airplane design that flew in 2021, as far as I can tell. I'm looking around and not finding anything contrary to that. Let's hope that interest can be sustained so we see more new designs and ideas.

The empty Bluebird now weighs 174 lbs. without fuel. Low weight contributes to low wing loading and thus slow flight, but it also allows me to forgo taxiing and just wheel the plane around on the ground.

I like the low power engine, it is quieter and gentler than the Moster engine used by the biplanes, but it does put you closer to the tree tops and bushes at first. After the first couple of hundred feet up, however, the lower power seems to make no significant difference to the flying experience. If you really want steep climbs you probably are going to require a more powerful engine, at least when starting much above sea level.

My engine is installed in the back, pushing the plane forward while keeping me out of the propwash. This allows me to fly comfortably in the open without walls or windshields, the same as a paramotor. This is a special experience that is one of the major rewards of flying slow.

Turn and bank reversals test the steering control, which seems about the same as for the Bloop biplanes. Rudder pressure or an occasional stomp against the turn is required to hold a substantial bank angle without getting steeper. For a normal turn I bring the inside wing tip down to visual alignment with the horizon and hold it there with some outside rudder pressure.

When taking my feet off the rudder pedals in level bank I expect to fly level, but if this results in a slight turn, always in the same direction,  then I adjust the rudder trim tab to get back to neutral yaw.

Pitch trim is provided by a tensioned bungee cord attached to the stick. Both rudder and elevator trim are adjusted on the ground, not in flight.

My usual final landing approach is onto an unpaved runway, coming in over a fifty foot high hill. This hill makes the first part of my 500ft. runway unusable without a good headwind. The Bluebird dives really well, and I can swoop down to ground level, but unfortunately the gain in airspeed will keep me floating above the runway until I reach pretty much the same stopping point I would have reached without diving.

I like the propeller clutch, allowing me to start the engine with an easy pull and little or no prop rotation. Also, it windmills at idle in flight and seems to be adding drag that helps me get down. However, in the event of an engine failure requiring a long glide to a landing spot, it could be problematic.

There seems to be a major problem for paramotor engines, they can sputter and loose power at high throttle settings due to small air leaks into the fuel system, and the bubbles can be hard to see during ground diagnostic tests. I'm considering raising the Bluebird fuel tank about a foot, level with the engine, as a more optimal placement, reducing the suction in the gas line. (The diaphragm fuel pump is part of the carburetor, it is driven by a crank case vacuum pulse pressure line). Notice the multi-line cable tensioners I use instead of turnbuckles, and the simple hand made aluminum fixtures for tube and motor attachment. There are squirrel holes in the landing field, some are craters you can put your whole foot down into. The small diameter wheels sometimes sometimes used by other aircraft (usually on hard surface runways) may not work so well here. I much prefer unpaved runways over pavement, the dirt is softer and more forgiving, and allows more stable rolling.

The paramotor engine setup is conventional. My idea with most airplane parts is to use readily available, "off the shelf" items in a conventional manner. Ordinary things can be done easily and quickly, so I can focus my creative efforts on the aspects of the design that really interest me. Building speed matters, since I want to finish and get the plane off the ground before the program bogs down and vaporizes, in he usual way of things. The Bluebird project is about making a slow flying airframe, so I avoid engine work by using an ordinary engine in an ordinary way. (I don't regard the engine as reliable, anyway, so I don't see it as essential to flight. The things you must have in the air are flight control, structural integrity, and the pilot being able to see.) To reduce noise the engine has an intake air box silencer and a tuned exhaust silencer, but it's still so loud  that ear protection must be worn by the pilot. (I look forward to an electric engine mainly for the presumed reliability, but also because with a quiet motor it will be worthwhile to use a quiet propeller with it, and then perhaps we can fly out in the open without ear plugs.) The black priming bulb in the fuel line has a check valve so that when it is squeezed some fuel is pumped back through the orange filter into the carburetor. This is just for starting after some interval of non-use. In the air, a restart might be assisted by advancing the throttle a little above idle. Filling the fuel tank as much as possible will not allow the full nominal 2-1/2 gallons, you can only fill up to the level of that rear black plug without leaking and that's all. I don't know how much fuel is actually usable, I haven't run out of gas yet. With oil mixed into it gasoline in the fuel tank looks orange. I'm considering raising the fuel tank up level with the engine (about a foot higher) to reduce suction pressure in the fuel line. This should help prevent bubbles in the fuel and might make the engine more reliable.

Fan Mail! "I owned a single and twin seat Quicksilver... I also owned a RAND X-Air. But it was the single seat MX1 that I enjoyed the most. There is something to say about simple uncomplicated 'basic bugs in the teeth' type of flying. Congratulations on all you have achieved  with all your aircraft designs and endeavors Mike. I am keen to build a Bluebird and was wondering if you had any intentions to eventually make any of the Bluebirds plans available?" "Can the wingspan be shortened?"	Thanks for the kudos and encouragement! Yes, I am completing drawings for the Bluebird and I hope to post them as I did for the Bloops and Bugs. There will be about 100 detailed technical drawings in folders for free downloading from this website. One set will be in PDF format, another in a CAD format, and perhaps an online viewable version that might be downloaded as  bitmaps. This all has to wait for me to finish the drawings, hopefully by next spring, 2022. As a preview, look at the Bloop 4 drawings, they will be similar. The Bluebird is even more specialized than my previous motorfloaters, it is not only for very slow flying but also an experiment in using minimal engine power. (My possible claim to fame is that it is the most efficient of gas powered recreational airplanes, using only 1.33 gallons of gas per hour). I like it, it's an adventure, but a bigger engine is probably going to be much desired by most recreational pilots. Those 16 hard pulling Italian horses are just not going to be enough for casual flying. Be advised that no larger engine has yet been used on the Bluebird so this would be an experiment. Slightly more powerful paramotor engines are readily available and I expect that any of them would be suitable. I've considered a new design based on the Bluebird that basically just chops off a foot of each wing (something like a clipped wing variant), but also allows shorter length. The idea is to reduce the dimensions while retaining the slow flying qualities. This ought to make the plane more practical, not needing as big a hangar. To recover some of the coefficient of lift of this reduced size wing I would make it thicker (more camber) and add more aft loading (also more camber, something like the lowering of full span flaps). A lot of efficiency will be lost due to the low aspect ratio (below 5) and thicker than optimal airfoil, so a slightly larger engine might be needed. Why not just build a biplane? Because I already did.
"Really appreciate the frequent updates on bluebird. Love the simple low power approach. Your philosophy of building and flying how ultralights were intended makes sense. It seems so many have gone to increased wing loading and bigger engines. I guess as a glider pilot I just never trust engines. I’d love to see a YouTube of you climbing to about 500 feet and kill the engine and make a dead stick landing. Also you mentioned electric propulsion. That wide center section might be ideal for multiple RC electric engines. Thanks for what you do and sharing. Looking forward to your reference drawings...I’d like take a crack at the rudder."	Yes, I suppose I should demonstrate an engine off landing, I haven't done that yet. I've done some climbing in lift, but only in small local updrafts because I'm too close to the ocean for good afternoon thermal lift. The main benefit of electric propulsion would be quiet flying. Motorized airplanes have always been loud, but now for the first time we may have a chance to get below the noise threshold and fly without ear plugs. My idea of a good electric setup would be a geared down motor driving a big prop. It might look like a ceiling fan rotating slowly (compared to an ordinary propeller), maybe less than 1000 rpm. That should be quiet enough to allow the ear protection to be set aside! I do admire the ingenious use of multiple small "off the shelf" motors to drive flight projects, but they do not provide the quiet system that I want.
"In regards to ... clipping the wingspan on bluebird, how about narrowing the center section. I know trailer ability is not a design priority for you but it looks like the outer wing panels might remove easy. If that center section was about 3 feet wide maybe it would fit in a trailer..."	The Bluebird center section is eight feet wide to provide a wide wheel track and hard points for attaching the sweep cables that stiffen the nose and tail structures. When you roll or land in a cross wind without ailerons you keep the nose low and that puts the weight on the wheels, allowing the widely spaced wheels to keep the wings level. Other two axis planes have flown with narrow wheel tracks, but I don't like being on the verge of tipping while ground rolling, and the wheels have proven to be effective for this, as well as otherwise functional and stable. Building a light, stiff airframe for an ultralight is hard, but the cable rigging of the Bloops and Bluebird, as well as the Goat glider, has proven to be worthwhile. This leads to a wide, bulky lower frame on the Bluebird. I'm going to keep it, maybe it will set a new style. How about an eight foot wide trailer?
" why [is] the bluebird's do-not-exceed speed is so slow? I get that it is supposed to be slow, but is 45 mph really the maximum limit? with 100lbs to spare, couldn't some of it have gone to more structure? ...would a slightly larger engine have any detrimental effect on the bluebird? (provided there is that aforementioned support)	In context, 45 mph. is fast for paragliders, hang gliders, and much of the slow flying crowd! It becomes much less comfortable to fly as speeds increase above 30 mph., the wind blast is undesired, which is why I'm not excited about other open frame planes such as the Quicksilver, which I regard as a fast and heavy airplane. Just about every other airplane in the universe which is not a motorfloater is designed to go fast, have you considered one of those? A larger engine will interfere with your flying and complicate control of the aircraft, and the increased dead weight on landing will require a longer runway. The safety advantages you gain from getting high faster may be questionable if you now need a bigger, smoother field for an emergency landing. A bigger engine will also require more fueling effort and usually will be more complex and harder to maintain, and noisier. Even so, in the Bluebird you probably would want a more powerful engine at higher altitudes,

Let's call this a "hole in one" landing. A clever detective would notice the wobbly wheel track from the squirrel crater to the bent landing gear struts, and would make a preliminary deduction that the motorfloater was attempting to land half way off the runway when a mishap occurred. Actually I was anticipating a cross wind from the left which wasn't there. I should just fly a good crab angle, as the need arises, and stay over the runway. After propping up the wing, bending the wheel back into position, and tying things in place with rope, I rolled the plane back to the hangar. As of right now the repairs have already been made, but I'm bracing and enlarging some of the landing gear struts for greater strength.

Thanks to Steve Leary for the flying videos, and to Floyd Fronius for taking the ground view flying photos. Floyd flew the Bluebird to give me a second opinion on it qualities, since he is an experienced Bloop pilot. Floyd wanted to go soaring the whole time, he seemed to have in mind a "thermal hunting" kind of sport where real altitude can be gained despite the small engine climb rate. I think he wants to take off in the desert to reach the base of a thermal at low altitude, then climb high by centering thermal lift. This should work quite well, but should not be confused with regular soaring since the reward will be getting high, not going far. There will be no high performance gliding between lift centers, just a motorized cruise.

These are the Bluebird controls as seen in flight. Those blue lines, used for the elevator and rudder, run back to the tail. All the control lines are out in the open and run down the centerline under the propeller. The lever on the left is the engine throttle, moving the red knob forward increases engine speed. Full power is supposed to be used only for short intervals to go easy on the engine (so it will keep running). Some lesser power is the usual cruise setting. The view and the breeze are stimulating to the experienced pilot. This is probably a lot like the paramotor situation, but with less harness confinement. The Bloop 2 biplane has crashed from about a hundred feet just after experimenting with very low airspeed, resulting in lots of damage but no pilot injury (I was not the pilot and can only make second hand comments). This was the only stall incident I know of in more than ten years of motorfloater flying. It is best to be high above the ground when experimenting and to be ready to do the stall recovery drill: "stick forward and apply opposite rudder".

 Bluebird is kept in a hangar for protection from the elements, and this also allows for a fast roll-out or roll in.

I wheel the plane around instead of taxiing, it's easy enough with a light and well balanced airframe. This is clean, quiet, safe, and saves engine time for flight instead of ground travel. I can scoot around onto or off of the runway while in the plane if I want to, but there is no allowance for slow rolling or sharp ground turns.

The empty weight of the Bluebird is almost 100 pounds short of the Part 103 limit. Many of the early ultralights were also very light because they were converted hang gliders. A 16 horsepower engine would also not have been unusual. The design ideas in use here are mostly about a hundred years old. The new aspect of the Bloop and Bluebird is the very low wing loading (i.e., using a big wing on a light airplane) which allows really slow flight. I don't like to talk about expenses because they can generate responses involving unrealistic prices and substitutions, but they are a real part of airplane building, so here they are. I think it cost me about $8,000 to build this airplane. I used new parts and materials for almost everything. The biggest cost variant would he the parachute, my hand deployed system cost about $1000, but a rocket chute could easily be several times that and might easily cost more than the engine. The engine and prop cost $3000, aluminum materials cost maybe $2000, "off the shelf" items $1000, fabric materials $1000, radio equipment and helmet was again maybe more than the engine. Almost all of my materials were bought from  large suppliers and shipped by ordinary parcel service. I limited aluminum stock to no longer than 8 foot pieces for delivery reasons. A slightly bigger engine should not increase the price much, but a more durable fabric job might.

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