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dbcisco
12-27-2008, 04:56 PM
This may sound like a stupid question but...

I have had success making plastic scale model helicopters into flying models and am wondering if anyone has done the same with airplane models.

MaxAdventure
12-27-2008, 05:23 PM
I think you'll have issues with wing loading and strength. In the Heli conversions I've seen, the structure is all based on the original mechanics, and the plastic model ends up being just a little over weight shell. With a plane, that shell is all you have and to get enough power to fly it, you're going to have serious structural issues. Also, the controls with a heli are all part of the original / doner air frame, with a plane you're going to have to fabricate all the control surface mechanics , using or replacing where they are on the model. This is so much more work than a heli conversion. If you try something, you HAVE to start a build thread and share!!!!!

dbcisco
12-27-2008, 05:38 PM
I was thinking of making a free flight model first. I would like to find out if I can even get one to stay in the sky. I thought of the Cox plastic control line models and thought, if they can fly...

MaxAdventure
12-27-2008, 05:57 PM
I was thinking of making a free flight model first. I would like to find out if I can even get one to stay in the sky. I thought of the Cox plastic control line models and thought, if they can fly...

You'll have to weigh them vs a model to get a better idea. That does sound like a good way to start. Regardless, you have to share you're build, even FF.

floss
12-27-2008, 07:53 PM
What scale would you try?

dbcisco
12-27-2008, 08:18 PM
What scale would you try?

Not sure yet. The larger the model, the better the density I think.

birdDog
12-27-2008, 09:12 PM
:DI have tried free flight with some plastic models in my younger days!
Didn't work so well. I think I may have even started fires on some of them!

I am so sorry, I could not help myself.:o

Please let us know how it goes. :)

floss
12-27-2008, 10:41 PM
Not sure yet. The larger the model, the better the density I think.

1/24 would be good but the cost would probably be near that of a flying model.

degreen60
12-27-2008, 11:05 PM
I flew some of the UC plastic models in the 60s. I did not own but sence I flew UC people that had bought the plastic ones asked me to fly them. The only one that I thought flew with any good control and would land was the Cox PT-19. I do remember one that as soon as the engine quit would tumble to the ground, had no glide, flew about as good as a rock on a string. I remember seeing someone fly a little larger plastic plane, think it had a .15 on it. Still did not have much of a glide after the engine quit. I think you will find plastic on the heavy side.

MaxAdventure
12-28-2008, 02:33 PM
well, give it enough motor so the thrust equals the weight and you know it will fly. Of course with a high wing loading it's going to go fast.

are you sure you want to go free flight to test? if you can get it to fly, it seems like it will get pretty small, pretty fast. I think you'd want to enlarge the tail for the initial tests, regardless. Once it's flying then try it scale. Just tape a little foam rudder on or something for the first tests.

I'm picturing an F4J with an EDF that's doing over 80MPH...

ooohhhhh!!! light weight, lots of thrust, dry fuel rockets! Start with a couple of Estes 'D' engines.....


http://www.badcataviation.com/pocr121cetou.html

holy giant plastic airplanes batman!!!!

they're huge! they're cheap! I've seen one of their tanks, they may be pretty light for the size....

eflight-ray
12-28-2008, 03:58 PM
If you can get a 'scale plastic kit' model to glide reasonably, not just a 'shallow dive', I would be surprised.

But to then add a receiver, motor, prop, ESC, servos, and a battery and it is still capable of gliding, (if the motor cuts, you don't want a flying brick), then you are on your way to making a fortune.

As someone already pointed out, put enough power on something and it will move through the air, (flying?, doubtful). I used to fly control line as well, (UC), and if it hadn't been for the lines, the smaller plastic models wouldn't gave gone very far. In fact when the engine stopped, we used to be able 'whip' them as it was called, we could still keep them in the air for a while by dragging the lines forward. You could do something similar with a stone on the end of a string.

If you look at the ultra small indoor RC models, which are about the same size as some plastic kits, check the weight of the model, they are usually only a few grams complete.

Even the bigger RC 'plastic' models are made from foamed plastics, EPS, EPP, Elapor, Depron etc. to keep the weight down.
There are the SPAD models, but I try not to think of them. :p>

Try it by all means, but weight is the greatest enemy to small RC models, the smaller they are the lower the wing loading has to be.

eflight-ray
12-28-2008, 04:10 PM
Forgot to link to what I feel are the smallest flyable model aircraft, (1/72 scale small enough), courtesy of the Leicester Aeronutz -

http://www.aeronutz.flyer.co.uk/

But do check the materials and especially the weight, (or should I say lack of weight).