DMS Trainer Plane
The DMS Trainer Plane project aims to create a simple, cheap, easy to fly trainer plane for new pilots. It will be constructed mostly out of Dollar Tree foam board, cut out on the Lasersaur Laser Cutter, and use some 3D printed parts. The idea is to utilize the tools we have at DMS in order to ease construction.
Ideally, we could hold regular classes where we build these, and then go fly at a nearby location.
Goals
- Constructed only using Dollar Tree foam board, hot glue, tape, and 3D printed parts
- Easy to build
- Easy to fly, stable and self-righting
- Good stall characteristics, no tip stalling or spinning
- Durable enough to survive hard or bad landings
- Easily replaceable wing, cowl, and tail parts
- Large enough to carry FPV gear
Specifications
- Wingspan: 58"
- Wing area: 464 sq. in.
- Wing loading (@48oz): 14.89 oz/sf
- Flying Weight: up to 48oz
- Controls: Ailerons, elevator, rudder, optional flaps
- Radio: 4ch required, 5ch for optional flaps
- Power system: 3s 11.1v LiPo, ~3200mAH, motor TBD, Prop size 10 to 12 inches
- Landing Gear: Taildragger setup, using off-the-shelf landing gear
- Flight time: ~15 minutes
- Target cost (Not including transmitter): Under $100
Wing Design
The wing is the easiest part of the plane to design, so I started with that. It is simply made by folding two halves over a spar, with the top sheet forming an airfoil shape. Lots of score lines were used on the top piece, so that it bends evenly and smoothly. The wing is a constant chord design, with a flat bottom and thick airfoil. This should provide good low-speed and high-lift characteristics. I went ahead and added flaps to the design, but they are optional. If flaps aren't needed/wanted on a build, they can simply be hot-glued in position, and have the servo holes taped over.
Fuselage Design
The fuselage is the most difficult piece to design, since it has many more pieces than the wing or tail planes. It also needs to mount the radio gear, battery, motor, and landing gear. One challenge is finding a strong way to mount the landing gear that won't simply break the foam board on a hard landing. Another challenge is the motor mount, which also needs to be glued to the foamboard in away that it won't easily come loose. The fuselage is being design with a removable cowl, making it easy to replace after a crash.
Progress
- 10/1/2015 - Wing design complete. Uses 2 sheets of foam board, 58" span, 8" constant chord. Aileron reflex will be used to prevent tip-stalling
- 10/3/2015 - Fuselage design started. Profile based on a Cessna 150.
- 10/5/2015 - Fuselage redesigned, original one was too wide and looked funny. Also switched to a one-piece 3d printed motor mount and landing gear mount. Added a steerable tail wheel mount.
- 10/13/2015 - Motor mount, cowl, and landing gear mount completed.
- 10/14/2015 - Tail brackets redesigned, tail and tailwheel installed.
- 10/17/2015 - Wing mounts designed an installed. Tail servos proving to be problematic with long control rods, will move servos closer to tail. Tail wheel also proving problematic, may revert to a simple tail skid.
To Do
- Refine tail brackets
- Add holes in tail for pushrods to exit
- Finalize split elevator - use either bamboo skewer, or dual control rods
- Install and test tail servos, wing servos
- Test flight
- Choose name for plane (something cool!)
