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In this photo the Live Wire is seen doing what it does so well, flying aerobatics. This was taken when Jef was making a low (about 10 feet above the ground) inverted pass (note the sunlight direction: this is not just printed upside down). Note how little down elevator is needed, even at the slow speed at which he was flying (going slow makes taking pictures like this a lot easier). Another detail you can see is that -- along with the other modifications discussed below -- the elevator planform has been modified to allow the rudder to swing a full 45 degrees to each side.
Photo taken by Thayer Syme whose own website ( www.mindspring.com/~thayer5/modelhp.html ) has many fine airplane pictures.
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This aerobatic RC model is the "Live Wire" from WattAge. Jef reviewed it for Fly RC magazine. He made a number of useful modifications, which include (from front to back):
- Use of a Hobby-Lobby brushless motor and APC prop
- Use of shorter landing gear wires and 1 3/4" "LYT" wheels.
- A side-opening, magnetically latched canopy (instead of using screws)
- Changed all-flying rudder to separate fin and rudder, and gave the rudder more room to swing by enlarging the cutout in the elevators
- Removed the "elephant ear" elevator overhangs and added them to the stabilizer. He then hinged the elevator across the entire span of the surface making it both stronger and more effective.
The plane is currently Jef's favorite aerobatic sport flier. It's symmetrical airfoil and 0 - 0 - 0 setup allow a wide range of aerobatics and it slows down to near walking speed without risk of tip-stalling, which makes landing easy. Details are in the published article.
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Jef's Electric "Hots"
The model plane is the funky-looking, electric-powered "Miss Bohemia" (www.hobby-lobby.com). The wing span is 1 meter, the weight about 460 grams. Pretty easy to fly, Jef used it mainly to teach beginners and to demonstrate rudder-elevator aerobatics (yes, you can do a roll without ailerons). It is shown flying over Pacifica's rough and rapidly-disappearing (about 30 cm per year as an average) Pacific Ocean coastline. Montara mountain is in the background. The closest building, now a private residence (and a rare example of the use of brick in this earthquake-prone area), once housed long-since defunct Dollar Radio's transmitters. They used to communicate with ships all over the Pacific Ocean. The old radio towers are long gone. Photo taken 2001 by Webmaster Aza. And no, the plane did not fall into the ocean, but landed back near Jef's feet. He sold the plane in 2003.
Considering that this site is only 8 km (5 mi) south of the San Francisco city line, it's surprising how rural parts of Pacifica can be. There are good fossil outcroppings near where this picture was taken.
For a review in Backyard Flyer magazine, Jef built this Wattage Tangent, which is an electric-powered aerobatic (what modelers call a "pattern") aircraft. It's smaller than you might think from the pictures, with a wingspan of only 80 cm and of about the same length.
The noteworthy item here is Jef's innovative use of Lego blocks to make sure that the aircraft surfaces are precisely aligned. He glued four large Lego "base-plates" to a sheet of plywood to make the base of the jig.
This is a 36-inch span scale model of the World War I Pfalz DIII single-seat fighter. It started out as a kit, but Jef found that as designed it flew poorly and would barely turn. Following a hint in a French model airplane magazine, Jef added ailerons. Using a computer-based transmitter, the rudder was coupled to the ailerons to eliminate the adverse yaw the ailerons alone generated (this was in accord with one of the basic ideas the Wright brothers patented). The inadequate motor supplied with the kit was replaced by an Astro Flight .020 brushless electric motor.
The wings were rather flexible, so diagonals were added between the interplane struts, and also between the cabane struts. The plane was then rigged, following the rigging pattern of the original, with Kevlar line. Tensioners, of a kind invented by Jef, are used to properly adjust the tension of the rigging and the alignment of the surfaces. Jef wrote about these techniques in an article in RC Micro Flight magazine (www.rcmicroflight.com).
He also substitued a pull-pull cable system to operate the elevator and rudder, and added bracing to the elevator, which tended to flutter otherwise. The wheels are all hand-made as commercial wheels of the right size and appearance were unavailable. The tail skid was replaced by a steerable tail wheel, because Jef usually flies from a hard-surfaced runway. It took much experimentation and many hairy flights, but eventually the model's bad aerodynamics were tamed, and Jef now often flies it on weekends. It flies very slowly, at a scale 90 mph or so, and looks very real in the air.
The ground photo was taken by Jef, the aerial photo (taking off into the morning mist) by Aza.
A 22-inch span, aerobatic, radio-controlled, slope-soaring sailplane designed and built by Jef and Aza Raskin. It weighs 105 grams. This is notable not only because it is cute, but because it is much smaller than most slope sloaring models which are typically about 50 inches in span and weigh over 1500 grams. All photos taken by Jef Raskin unless otherwise noted. These two photos taken with the Agfa ePhoto 1280
Jef has always enjoyed making paper airplanes. The green plane is a Sopwith Pup from a Fiddler's Green kit. A "kit" in this case is a single sheet of card stock with the plane's parts printed on it. The brown plane was Jef's first attempt at building one of these kits, an SE-5a. This picture gives you an idea of how small these planes are. Orange wings adorn a paper model of the famous Sopwith Camel, from the same series of model kits (which cost about $1.50 each). The photo of the Pup was taken with a Minolta D-5 digital camera, used on a tripod. The SE-5a was taken with the Agfa ePhoto 1280: Jef held the camera in his right hand, the plane in his left. This is the best shot of Jef's fingers you are likely to find on the whole web! Webmaster Aza took the shot of the Camel with the ePhoto 1280.
An all-cardboard (except for landing gear, electronics, propeller, and motor) electric-powered radio-controlled model. It's about 45 inches in span. The way it is built is unusual: Jef prints out sheets of paper — with cut and score lines as well as colored decorations — on his wide-carriage Epson 1520 printer. He then cuts and scores on the lines, glues the pieces together with a hot glue gun, and in two or three hours has a brand-new plane. Since this first one was built, Jef has started using a friend's cardboard prototyping machine to make the parts (from DXF files Jef creates with Ashlar's wonderful and easy-to-use Vellum CAD package (those are Jef's words)).
Power for this model is an MEC Turbo 10 motor with a 6:1 gearbox. An SR 1800 mAh battery supplies the power. Motor controller and radio are by HiTec. Tiny HiTec HS-80 servos control the surfaces. Flights of 12 to 15 minutes are standard. The plane weighs 1470 grams (about 3 lbs), which is the same weight as planes of this size made with standard balsa or composite construction.
Jef has been building cardboard R/C models since the 1970s, over 2500 of his Western Wind sailplane kits, also with all-cardboard construction, were sold.
The dedicated modeler is always looking for appropriate
subjects to replicate in miniature. The photo shows a semi-scale De Havilland
DH-3 aircraft. The prototype was built early during World War I, and led
to the mass-produced DH-10 later in the war.
This model, of 28 inches span, built by Yesso Tekerian, is a quick mock-up
put together to test a few ideas. It is radio-controlled with motor, elevator,
and rudder controls and the motors are electric, power coming from a NiCd
battery. It uses the motors from a styrofoam B-2 flying wing kit, and
is built almost entirely from 1/32" balsa. Such thin balsa is very
flimsy, yet the model has proved to be quite sturdy. Following early biplane
practice, the fin and stabilizer are strut-braced. The wings are incredibly
rigid because of the rigging, which is made from very fine kevlar fishing
line (Spider Wire 5 lb. test). Kevlar, the stuff used in bullet-proof
vests, has almost no stretch and is stronger for its weight than steel.
A common problem with making flying models of early biplane designs is
that they tend to have very short noses (see the photo of the models of
the Sopwith Camel for a typical example) making them difficult to balance
so that they fly well. The DH-3 has a very long nose, one that is unobstructed
by having a motor and propeller in the front, and it is therefore easy
to put the battery in the front of the nose, making balancing very easy.
Another advantage of this design is that the propellers and motors are
protected in case of a hard landing. Most planes have the propeller up
front, so that broken props and bent motor shafts are a common hazard.
Now that the concept has been shown to work, we will be building some
better-looking models of this aircraft.