Slow flying mini speedster

[gellings]

This little plane was built because I needed something that I could fly after work without having to go all the way to the park. The goal was to fly slow. I am not an expert here and it wasn't ever very maneuverable but it did fly slow enough to fly around my small apartment complex (which was a blast!).




You probably can't tell from the video but it flys about the speed of a brisk walk

As it says in the video, I removed as much foam and paper as possible to save on weight. It looks pretty fragile but it was so light and slow that it also didn't crash hard. I actually crashed it over and over until the prop started to brake before the foam board ever started to wear out.

I used a micro receiver from hobby king. It has an integrated receiver, brushed esc, and two linear servos. The battery is a 370 mAh cell that I had lying around. I also used a motor and prop from a little air hogs helicopter toy that I had. I was going to remove the stabilizer bar but never got around to it. I think it would have been much more maneuverable if I had removed it.

receiver

battery

motor and prop that I used

motor and prop that probably would work better

View attachment minispeedter.pdf the scale might be wrong, sorry. The rectangle should be a standard 20x30 inch foam board sheet

This was very much a first iteration so don't hate. If I built it again I would not remove as much foam from the fuselage and tail for stiffness (see the pdf). I would probably also add wheels and stuff for ascetics.

So here is my example slow flying foam board plane... I also hope Josh Bixler doesn't mind it being such a blatant rip off of his design.

 

[pressalltheknobs]

Hey man that's really cool! Very nicely done. Have been thinking of doing something similar but haven't had the time. Great to see it working.

What does the air-frame weigh? How does it take crashes? Any recommendations/lessons-learned on how to lay out what foam gets removed? It looks fairly straight forward from the plan - mostly outside frame with braced rectangles in the wings, but would you do it any differently now you have it working?

 

[kacknor]

Was it coincidence that I just ordered 5 gram motors and 6 amp ESCs from HK? I think not. Fate, fate and a need for indoor flyers.
Outstanding work on the frame and wing cutout idea. That is something I will try...

Thank you!

JD

 

[reburg99]

Nice job!

 

[kacknor]

Did you peel the paper before you cut the cavities? Or cut through half and dig it out? I can see me peeling both sides, cutting my parts and re surfacing the foam with tissue or other thin paper before assemply. Inquiring minds...

 

[gellings]

Did you peel the paper before you cut the cavities? Or cut through half and dig it out? I can see me peeling both sides, cutting my parts and re surfacing the foam with tissue or other thin paper before assemply. Inquiring minds...

Thanks for the reply!

I left the paper on and dug it out with a knife and screw driver. I also left paper on both sides in some places for stiffness. The foam gets real flimsy and doesn't hold a shape if you only have paper on one side of the foam. This plane didn't fly well if the wing got twisted even the slightest.

Resurfacing might work if you can keep everything stiff enough.

 

[gellings]

What does the air-frame weigh? How does it take crashes? Any recommendations/lessons-learned on how to lay out what foam gets removed? It looks fairly straight forward from the plan - mostly outside frame with braced rectangles in the wings, but would you do it any differently now you have it working?

Not sure what the weight is. If I can find a postage scale then I'll let you know.

It took crashes remarkably well. The picture above is after crashing over and over. The key is to keep your weight to the absolute minimum. less weight means less airspeed means less kinetic energy means less damage in a crash.

In laying out where to keep foam I just figured I would keep it where it would provide shape and strength. It certainly wasn't very scientific...

If I did it again I would not remove any foam from the empennage (tail section of the fuselage), I also might try ailerons to make it more maneuverable (slow fly mini sportster...). The maneuverability was very limited.

The goal for this version was just to fly as slow as possible. Keep your weight down and it will float.

 

[kacknor]

A bit of thin carbon fiber rod to stiffen things and maybe a thin strip of balsa at the hinges and mounting points. To tighten the paper I suppose dope and lacquer thinner would melt foam, but I don't know. Maybe a thin coat of 50/50 water and Elmer's glue? I read something just today about that being used. Don't recall where. Could always just wipe or brush on Minwax after assembly. Really thin CA would work, but that's a lot of area...

I'll need to scale up a bit, if I do it, to match the electronics I have...

Added:

Here it is... http://forum.flitetest.com/showthread.php?23788-Elmers-glue-foamboard-coating

 

[kacknor]

Thanks for the reply!

I left the paper on and dug it out with a knife and screw driver. I also left paper on both sides in some places for stiffness. The foam gets real flimsy and doesn't hold a shape if you only have paper on one side of the foam. This plane didn't fly well if the wing got twisted even the slightest.

Resurfacing might work if you can keep everything stiff enough.

Thank you for trying it! I did a simple test in conjunction with another thread that dovetailed with this one on waterproofing and paper stretching. Think I'm going to take your paper and foam cutting idea and apply to it a Mini Sportster. No Idea if it will turn out OK. Likely not as slow, but I'm thnking of some ways to change the wing. Here is the first test. Just a bit of foam hacking and Minwax to tighten it up...



JD