Bloop 1 & 2
Jul 17, 2011Public
Photo: Bloop 2 is intended to be a simple and easy to fly recreational airplane for pilots who just want to get up and fly around. I call it a motorfloater, different from all other airplanes and ultralights because of its predictable and non-hazardous slow speed flight characteristics. It flies much like a paramotor, slow and forgiving, mainly because it has a very light wing loading, less than two pounds of loaded weight per square foot of wing.
Photo: Bloop 2 is colorful. It will attract bees and hopefully will be easily seen by faster aircraft. It has a high lift airfoil, an empty weight of about 195 pounds, and a level cruise speed of 24 mph. Turns are made using only the rudder, which is attached to the foot pedals.
The box kite biplane structure provides a big wing in a small package, with good torsional stiffness, primary strength, and pilot protection in a crash.
Most ultralight airplanes are fragile and hard to fly, but our best opportunity for safe and easy flying is to turn that around by deliberate design,
sacrificing speed and range to create a new kind of airplane. Low speeds will make the plane comfortable and easy to fly, while enhanced crash safety will turn tragedy into comedy in most impact situations.
This is a no longer a new airplane, it has been flying since early July, 2012. So far it has flown well and I am quite comfortable in it. 
I have no commercial plans for any motorfloaters, but I hope I can interest some builders and fliers in joining me in exploring the possibilities of slow flight.
Photo: My basic motorfloater rules are: cruise with the nose near level, steer with the feet, and stay away from power lines and deep water. 
This takeoff from pavement is unusual, I normally fly from an unpaved runway. Dirt strips seem softer and more stable on my BMX bicycle wheels. The wheels are at the center of balance, so I can land on the tail or nose as I choose, but only the nose skid makes a decent ground brake, the tail skid does not seem to have enough weight on it to have any stopping power.
Photo: Pursued by my shadow, the engine and runway are hidden behind me as I climb away from a dirt strip takeoff. I started off on the ground at a point just behind the top of my helmet. 
My left hand is on the throttle lever at the full power position. I try not to use full power for more than 30 seconds to keep from over heating my little engine.
The horizontal tail planes are a little twisty looking, the way they were built, functional if not beautiful. [June 2013]
Photo: I don't feel the wind much, it's about like riding a scooter, just a mild breeze.
You can see a little mirror mounted vertically on the wing just outboard of my left elbow. That allows me to look back and see how much fuel is in the gas tank. I usually fly with gages for engine speed and engine temperature, but I think I could fly well enough without any of the instruments, except for that little mirror.
Photo: Climbing out at full power over the runway, the nose is up about 20 degrees. This is the maximum but ordinary nose attitude that I hold continuously on takeoff  to get my best climb angle. In more heavily loaded aircraft this might be hazardous, but in the Bloop 2 I can bring the stick full back (gently) without an abrupt loss of control. With full throttle at high nose up angles the plane will continue to climb, perhaps not well or smoothly, but there is no uncommanded descent (i.e., Bloop does not seem to exhibit the hazard of flight behind the power curve, descending despite full engine power, at  least not at my body weight.)
Photo: The easy method of setting up a final approach to landing is throttling the engine back to idle and diving down to the near end of the runway. This works because the Bloop does not gain much speed in a dive. A draggy bird cage airframe (the notorious built in headwind)  is exactly what you want for easy landings.
Notice the use of multi-lacings for cable tensioning, not turnbuckles. The joke: not all my ideas go back 100 years, some go back 300 years.
Photo: The Bloop engine is a 25 horsepower Vittorazi Moster 185 (185 cubic centimeters displacement) with its 1.3 meter (diameter) carbon composite propeller, a modern paramotor system. The translucent plastic fuel tank will hold 2-1/2 gallons of aviation gasoline mixed with synthetic oil. The combination air filter and inlet silencer is the big light brown bulb mounted on the carburetor. The red spot on the carburetor is where I attached the magneto groundng wire onto an engine bracket and taped it over. The prop tends to get oily because it passes through the exhaust stream, which still has a lot of oil in it that was mixed into the fuel. The utility bag mounted on the back of the seat is useful for stowing small tools, lubricant, hats, cameras, and so forth.
One spark plug, one cylinder, one carburetor, and a pull rope for starting. The butterfly carburetor includes a fuel pump so the gas tank can be located below the engine. There is no float bowl, the fuel system is sealed except for the static port on the fuel tank.
Photo: Having the engine in back instead of in front makes the flight quieter and less windy for the pilot, as well as keeping the oily exhaust off of things. While on the ground, people are kept safely away from the propeller by the tail structure and bracing cables. The single rudder of the Bloop 2 is in the propwash so it provides good steering control at low speeds while the plane is rolling on the runway. With the propeller located over the lower wing, noise is reflected upward, making things quieter on the ground, and the propeller is protected from gravel strikes and brush.
Photo: In Bloop 2 I'm headed back to my home field, seen in the distance. It's a warm afternoon at the end of July, so I'm flying in hiking shorts and a tee shirt. Flying slow, I have lots of time to look around and enjoy the view. (My one original invention: a new way to stow shoe laces.)
Photo: This is the Bloop 2 nose in September, 2014. Attached to the foot pedals, my rudder control line materials are the same as the running rigging on a small sailboat (braided Dyneema/Vectran lines routed through marine pulleys, tied off at the ends). The traditional rigid nose skid, sailplane style, is gone, replaced by an elastic nose skid. This skid serves as my ground brake in the nose down landing attitude, which is frequently used.
Photo: Here's the view forward over the unoccupied pilot's seat. The control stick operates only the elevator, sliding fore and aft between the two brass rails. The foot pedals are the only steering control. The two instruments are a tachometer (engine revolutions per minute) and an EGT gage (exhaust gas temperature). The covered red switch is for engine spark plug grounding, it is in the "engine off" position. Since the engine is not running. the tach will display the total hours of engine operation instead of engine speed (look close and you can read "28" on the tachometer). To the right of the instruments you can see the lower end of the elastic nose skid with its aluminum skid pad (old style) for ground contact during braking. The upper and lower set of sweep cables can be seen, they combine to resist twisting of the nose section.
Barely seen is the bungee trim cord that provides back force on the stick to help keep the nose up in flight. This is just a tensioned elastic shock cord tied from the control stick to the airframe at the back of the lower wing, it is not adjustable in flight. This cord makes the airplane easier to fly since you don't have to hold as much or any continuous back force on the stick.
Photo: The two axis control system is effective but takes some getting used to. The initial skid pushes the pilot toward the outside of the turn, like a car turning on a flat road. I make ordinary local flights with this system, doing the same maneuvers as with the three axis system, except for slips, which I don't really need for cross winds at my very slow landing speeds. The photo shows a bank of about 28 degrees, a steep turning maneuver.
Photo: The pilot flies completely in the open. The total recovery system (the emergency parachute that brings down the pilot and airplane together) is in the purple bag. The elevator and rudder control lines can be seen running under the wing from the nose section back to the pulley block. That snazzy curved control stick was made from an aluminum walking cane, and the seat was made for a boat (both from Walmart). The four point seat belts are the push button, automotive "dune buggy" type, because I could not find a suitable aircraft belt (you do not want an aircraft quick release!). Just below the top of the nose tube, the handle for pull starting the engine can be seen, above the pilot's head where it can be reached in flight.
Photo: Bloop 2 in November, 2012, a gentle and predictable flying machine. The wide track landing gear makes for stable ground rolling. The large diameter BMX (Bicycle Motocross) bicycle wheels are a little bit stiff, but good for rolling over gopher holes, and they are also good for the minor hopping and skidding that can result from takeoffs and landings with a two axis control system. I begin the take off with the tail on the ground, in the attitude shown here. I usually stop with the nose down, so I have a ground brake, but sometines I stop on the tail for fun and style. The tail skid does not really make a good ground brake, it is too lightly loaded, especially with the pilot aboard.
Photo: I don't taxi, I just walk the Bloop out to the flying area. The engine is running, completing its warm up as as I roll it out to the runway.
You don't want to taxi (to move around on the ground while sitting in the plane) when you don't have to, because then you have poor control and visibility, you are wearing out your engine without flying, and you are making noise and raising dust all over the place.
When seated in the plane, rolling on the ground, I can use engine power to "scoot" onto or off a runway if I need to accommodate other traffic.
Photo: Bloop 2 is on final approach to a dirt strip....The Bloop flies like it has flaps down all the time. It does not gain much speed in an engine idle dive, nor does it float far in ground effect. To make a minimum skill landing approach I can just dive down to the end of the runway and then let it settle into a ground roll.
Photo: A three view drawing of the Bloop 2 with basic information. The Bloop is constructed from aluminum tubes bolted together and braced with braided steel cable. The fabric covering is a light version of a conventional aircraft process. It uses polyester cloth, heat shrunk onto the frame and brushed with aircraft dope. Complete and detailed drawings are available elsewhere on this website.
Photo: This is Bloop 1, the previous version of the Bloop, which I flew in the summer of 2011. It has a box tail and twin rudders, a simple and rigid setup. The flat bottom airfoil on the main wings flew well enough and made the big panels easy to build. Although the twin rudders may have been more efficient out in the smooth air, the current version (Bloop 2) with a single rudder on center line in the prop wash has much greater steering authority on the ground at low speeds.
Photo: The Bloop airframe is garage technology, hand made, mostly with tubes, cables, and bolts. There is no welding, molding, sheet metal work, nor specialized machining. This "hand tool and vice" approach allows easy part duplication and replacement for repair.
Photo: Bloop 2 in my workshop, a pile of parts until it is assembled. Bloop 3 is a big improvement in the shop work because it has a free standing center section that can be set up in the shop, allowing indoor work on large assemblies. If this were Bloop 3, you would see the center section assembled in the center of the room, and I could be working on the landing gear, nose, or tail section attached to that, without having to set up the whole wing frame in the backyard.
Photo: Bloop 2 leading edge construction. These blocks of blue Styrofoam are attached between the ribs with epoxy glue, then shaved down to the rib contour with a hand tool (Surform shaver).  A lot of this foam is going to end up on the floor (it's a big mess!) . Filling and sanding will later create a smooth curved surface. This leading edge shell is non-structural, it just holds the airfoil shape at the front of the wing.
Photo: A finished Bloop 2 wing panel is ready for its fabric covering. There are no lower surface ribs, the lower surface fabric consists mostly of three large, flat panels attached to the internal compression struts and main spars. In flight the unsupported fabric on the bottom of the wing usually deflects into a slight undercamber. The Styrofoam leading edge shell has been smoothed, then sealed with epoxy to prevent the fabric dope from dissolving the foam.
Photo: Bloop 2 rudder, with foam cores in place for rib construction.