Backwards Airplane
In this challenge, Peter tries to make his Lunar Eclipse plane fly backwards using most of the existing control surfaces!
Because the rudder needed to be adjusted so the plane could straighten out when flying backwards, Peter began by removing the old rudder and constructing a new one.
Then he added a vertical stabilizer to the wing tips and an acrylic vertical stabilizer to the nose. To make it lighter, Peter cut out some of the acrylic and used tape to fill it out.
Then he ripped out the old nose and glued a new power pod to the front of the plane.
The first test flight was pretty unstable...the plane only stayed airborne for a few seconds.
Peter cut some more off of the old rudder and added some more weight by taping a wrench to the fuselage.
Attempt number two was also unsuccessful. Peter completely removed the old rudder and added a new rudder to the acrylic vertical stabilizer. He also drilled a hole into the rudder and used some lines to tie it to the servos and added more weight.
After two more attempts, we realized that the backwards tail did not work, so Peter flipped the wing around and added three AA batteries on top of the wrench to balance the weight.
This flight looked good…until Peter flew into a pole. :)
Basically we learned that it’s possible to make things fly that aren’t supposed to fly. Unless you run into poles.
Have fun with old airframes by trying to get them to fly backwards, and let us know what challenges you want to see next in the comments!
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Thanks
Charlie Spann
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thanks Peter!
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I would like to see an FT canard. Something made from foam board that flies really good.
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Will
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it's the old spirit of FliteTest
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The backwards ailerons don't usually work, but the rudder and some dihedral usually do.
Yaw stability can be enhanced by canting the winglets inward (toe in) relative the the canard direction of travel. This technique was originally used (as far as I know) on the Johnathan Livingston Seagull gliders for the movie in the 70's. They used small disks made of clear plastic.
The forward vertical stabalizer that Peter removed can be retained visually by placing it on a pivot so it just weathervanes in the wind. Aerodynamically it won't even be there but visually it still is.
Alternately a forward vertical stabilizer can be made to work using active stabilization from a gyro or flight controller. A fully flying vertical stabilizer is recommended in that case. This technique has been demonstrated in some flying pterodactyl models.
The biggest issue is just to get the CG correct. It needs to move a long way back towards the tail (forward towards the nose for a canard). Peter figured that out the hard way.
Having the wing airfoil backwards is far from ideal, but not a huge issue. We fly flat plate wings all the time and they have no backwards. Turning the airfoil right way round is not much of a visual problem though, especially if you use a traditional trim scheme that suggests the wing is really in the normal direction.
Putting the ailerons on the trailing edge (relative to canard airflow) would help a lot, but like I said, you don't even need ailerons if you have dihedral and a working rudder. It isn't too visually bad to have them though. In flight you can't really see them. Some pin stripe tape suggesting ailerons where they aren't even there helps with the illusion.
The end result of all this is usually a pretty marginal flying airplane, although with some work you can make it fly pretty good. Keeping it light is a big help. Moving the battery all the way to the tip of the tail (nose) is a big help as it mostly avoids heavy wrenches and other ballast which are not good for the flight performance of any airplane.
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peter i like those guienie pig and ft bushwackers.you guys have made lots of scale models.but i was thinking that more model of cargo aircrafts or more like model of 737/747 etc.. would be awesome.i was hopping if there will be any models like it that flite test is going to build.grin emoticon
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I've taken up your challenge and am converting a small Skylane. The big problem is getting the cg forward without adding too much weight. Lengthening the fuse appears to be the only solution. The rudder (now at the front) is free flapping and it is on floats. Flight tests will be on the first suitable day.
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