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Ode to a Fat Little Flier (**UPDATE** Build Log Finished, Plans Posted)
(Update: Build log starts in post 29, Plans at the end of 1st Post and Letter page size plans in post 62)
Here follows my first scratchbuild foamie thread. It is the first plane I made a promise to, that I would make for it its own special thread, if it flies, and it does so I do not want to hurt its feelings. Some history: Some time ago I stumbled across Fred Reese’s Buttercup and I thought to myself, “That’s a pretty cute plane.” Not too long after that Steven’s Aero released the Mud Bug and I thought to myself, once again, “dang that’s a pretty cute plane!” My mind was made up when I saw an animated plane fly by on a TV commercial (I have no idea what commercial) and I decided to attempt to make my own (hopefully cute) plane. Some more: The original plan was, and still is, to build this little critter out of balsa and some solite but having little faith in my still somewhat untested ability at creating something from sticks (and not returning the poor creation to its pre-conceived state on the first flight). I decided to build from some depronish foam I found lying on a dump at a construction site walking home from the supermarket one day. The foam (3mm) is about 1.6 times the weight of depron (as I know it in the US) for a sheet of similar dimensions, but it was free so the weight to cost ratio was just about right I am still not totally sure about the name, but I like “Tubby” since it is just that. Any comments\critiques are welcome on any part of this creation. Her Specs: Wingspan: ~24 inches Dihedral: ~+4 degrees per wing half from horizontal Length: ~15.5 inches Wing Area: ~0.82 sq-ft AUW: ~6.33oz (yes I know she’s tubby) Wing Loading: ~7.2oz/sq-ft Motor: ELE C-20 kit from Strong RC, wound 16T Prop: GWS 6x5SF till I broke it, now APC 5x5 because it’s all I have Battery: Kokam 3s 350mAh ESC: GWS 15A, didn’t want to risk my CC Phoenix 10 and am waiting for a Pentium 6A RX: GWS pico 4Ch with The Don’s base loaded antenna Servos: 2x Futaba s3110 (Rudder, Elevator) The construction was quite straight forward. The fuse went together pretty quickly. The wing was made in two halves, the foam scored and folded over a foam spar to get a flat bottomed airfoil of sorts (Saw that done somewhere on here, thanks!). The wingtips raised, the area at the joint sanded to get the dihedral, glued and taped at the joint. The wing joint is surprisingly quite strong and has not broken after a few crashes. The wing is attached to the fuse using rubber bands. The rudder was based loosely off an Aeronca Champ as I love how it looks and the elevator I secretly “borrowed” from Demon-Leather’s “Pseudo Pa-Nee” no plans thread, I hope he doesn’t mind. When I saw the elevator I knew that was what I wanted for my little Tubby. I was hoping to put some Trexler balloon wheels on her, like the Mud Bug, but I don’t have the funds to pay for such expensive wheels right now, so I used some GWS 3” wheels that I had lying around until I get a set of foam 3” wheels in the near future and then maybe one day I’ll save up enough for some balloon wheels. The tail skid is just a piece of 3x0.5mm carbon fiber glued into the back of the fuse. Ground clearance at the lowest point of the plane is maybe 05 inches, not much but she handles rough ground OK. Trimming was a bit of a challenge and I am still fine tuning the thrust angle on the motor, right now it’s very roughly 3 degrees right and almost the same down. The short tail moment has not been as hard to fly as I thought it might be, she actually flies very nicely. Not much, but a bit of speed is needed to remain airborne and land, I blame the heavier electronics and foam. She does not like much wind, as can be seen at the end of the video clip. Video's are located here The videos are, first: a flight ending in a bit of a crash, second: some flying with music and lastly the maiden flight. These are my first ever video creations and posting so go easy on me please. The last “landing” on the third video I turned downwind and the wind picked up, I struggled to turn back upwind, stalled, and she turned gymnast on me and cart wheeled. Had I been a better pilot I’m sure I could have landed or done something fancy, but I have to work with the limited skills I got at this time. The only damage was the foam around the landing gear tore a little, some glue and she’s flying again. I have spent many, MANY hours reading and learning here on RC groups, I haven’t posted much but I would like to thank everyone for all time and effort spent typing and putting together all this great info to learn from. Those that have helped me via email or PM, thank you! A special thank you to my cute, loving and supportive girlfriend, who took all the video and remained patient through hours of: “Which one looks cuter?” and “What do you think about this dearest?” I wanted to name the plane after her but the whole “tubby” thing didn’t sit too well… I will continue my quest of getting this critter balsa-fied with a little more confidence and probably make another foam version or 2 in the process, just because.Once again, any comments\critiques, even questions, are welcome. Thanks for looking, Bob **Plans Added** Here are the plans as I have them right now, I will look into the PDF thing but for now here are the .dft (Free Solid Edge 2D) and .DWG files as best as I could make them. If anyone feels any changes are necessary, please let me know I'll do my best. I will start another build of Tubby this week to check the plans also the current "test run" Tubby is a little sad looking with holes cut to save some weight and some scruffy balsa reinforcing the landing gear. The landing gear is a bit sensitive to overly hard landings (read: cartwheeling crashes), feel free to modify and/or give some suggestions, it handles most landings pretty well though. I only included the easier to make under camber wing as the original does not fly as well and I didn't feel like trying to recreate it in CAD, will do it though if anyone is interested. I did not change the fuse to support the camber of the wing better but it should be easy to do, the wing holds just fine as is. Video will be posted another day, I need to go to bed. I hope someone out there gives Tubby a try, and if you do I'd love to see some ideas for color schemes. Bob **PDF Plans added** I think I figured out the PDF thing, files added in PDF format, let me know if it's OK, PDF page size is 11x17inches The latest Tubby 2: [attachment]1597535&d=1196641572[/attachment] |
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Bob,
To use a presidential term, I think you're "misunderestimating" your talent. ![]() Here are a couple of Buttercup threads: http://www.rcgroups.com/forums/showthread.php?t=628795 http://www.rcgroups.com/forums/showt...t=561552&pp=20 Video on post 69: http://www.rcgroups.com/forums/showt...2&page=4&pp=20 Enjoy your FFF! Pat PS My daughter leaves next week to teach English in Quito, Ecuador. |
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