8 Ft Wingspan Coroplast RC Piper Cub Flown by 25cc Weed Trimmer

I love Radio controlled airplanes and have built several kinds from balsa to this large scale plastic one.

This one is made from $25.00 worth of plastic I bought locally at a sign company.
The plastic is Coroplast or corrugated plastic, its cheap and builds fast.

You could also use old election signs, you just need to paint them or make a patchwork airplane.

Total cost with radio and motor was around 350 bucks.

This is an extensive build and can be scaled down for a smaller plane if you wish.
A working knowledge of RC airplanes is recommended to build one of these.

Its also a tough model, it can take several crashes without too much problem.

I have built a couple of the Aircore brand fold and glue airplanes and used them to learn how to fly, I strongly recommend starting out with one if you want to get into glow engine airplanes.

Balanced properly its a predictable airframe. Due to the simplified flat wing it will tip stall with you at low speeds, so learn how it stalls at high altitude before slowing down for your landing. The ailerons are large enough for a decent roll rate.

As with all gas powered airplanes please be careful wile starting it and have fun flying.

Zachary M.

Step 1: Specifications:

Semi Scale J4 Super Cub

8 Foot wingspan 16" chord wing with landing flaps
4.6 Foot fuselage without motor, I moved the motor forward to balance the airplane. So max length can be 5.75 feet

25cc motor with 9.5 pounds of thrust.

Total weight with fuel is 15.75 pounds.

Max speed around 45MPH

Comments

[jonathan1976]

hello, i am about 3 quarters of the way through with the construction of my plane using yours as a guide. i have made some changes. i could not get the coroplast to hold using the glue. i used pop rivets (1/2 inch) with aluminum washers on the other side to hold the wing together. instead of using 2mm coroplast on the top of the wing i used 1mm plastic that i salvaged from an old sign. i also made my own landing gear from an old sign that was 1/8" aluminum. i made it to the measurements from the ordering page in the catalog. i cut it to shape and used a metal break to bend it, it turned out nice. i didn't exactly know how to mount my engine so i drilled two holes in the engine mount (one on each side) and tapered them and using blind nuts i bolted it to the firewall. also you must have had something that turned your carb sideways because i had to make a throttle linkage that bolted to my crankcase to pull the throttle straight back. so i had to mount my throttle servo inside my fusalage and drill a hole through the firewall to connect my pushrod. another thing i did was drill some small holes in the hinge about 2" apart to make the hinges on the tail easier to bend. i am waiting to order my radio so i can get this thing airborn. i have tuned it and fully loaded (minus the receiver) it weighs 16+ pounds.i just wanted to say thank you for all your help and wish me luck

[anime_grl]

hello! would anyone be able to send me links of where i can get some of these items online? pleease??

[DOMINICKGRIGGS]

how does it turn

[he who crashes often]

i didn't make this instructable, but almost all radio controlled airplanes of this size use servomotors to move the ailerons, rudder, and elevator to turn, the same way a full-size airplane does. to initiate a coordinated left turn, you give left aileron and rudder, then slowly increase rudder while bringing the aileron stick back to neutral, using the elevator to prevent it from nosing over. you then neutralize the rudder, and give a bit of right aileron to bring it back to level. do the reverse of this for a right turn.

[Herminator]

Wow this is awesome! Planning on building this when I finish year 12.

I noticed in the Parts list that the Gas tank conversion kit, it says in the specs (do not use with Flextanks) but the tank in the parts list is a Flextank. Is that an error or does that tank hold up to gas?

One more question, I only have access to 900x600x3MM thick coroplast, would that be ok for the whole plane including the top and bottom of the wing?
BTW I will be making a two piece wing for easy transport with a small wooden spar in each wing plus a removable metal tube that goes into both wings so they don't fold.

I was actually already thinking of making a cub with a 25cc weedwacker engine then found this incredible instructable, made my day!

Thanks for your time! :)

[nickademuss]

Oh he fuel tank....the tank itself works fine, the stopper and tubes that come with are not gas safe, the conversion kit makes it safe...

[Herminator]

So i can now get a hold of 5mm and 3mm coroplast in 900x600mm sheets, its already underpowered with the 25cc weedwacker, do you think 5&3 for the wing would be too heavy?

Also i have already purchased five of these for the wing/throttle.
http://www.hobbyking.com/hobbyking/store/__16269__HK15138_Standard_Analog_Servo_38g_4_3kg_0_17s_.html

Would this be a suitable servo for the tail surfaces?
http://www.hobbyking.com/hobbyking/store/__9655__Power_HD_Standard_Servo_43g_5_8kg_16sec.html

Just wanna make sure before i go ahead and start building :P.

[nickademuss]

The rudder dont need as much power as the elevator, I would go at least 100 Oz torque on it. Thats the only way you will be sure to get enough control in a crisis situation.

!8cc was underpowered, 25cc tuned was pretty good, 35cc would be great :)

As to the thickness you plkan on using, it will work, but it will be slightly heavier and hard to fold.... 2mm top wing was easy to build...

[nickademuss]

I used 2mm for the top of the wing because it curves and bends easy, 3 mm may be to thick for that, the rest could be made with 3mm though it may not be as ridged as 4mm for the hull and bottom of the wing.

I tried to make a two piece wing once, the problem you will see is that when you make a long wing it gets much more support from the long length of coroplast on the bottom and it stops the flexible plastic from giving. The two pier one I made with an aluminum pipe for a center spar let the whole wing flex allot so much I was afraid to fly it. You might have better luck!

Thanks for the comment! Ad good luck

[donphipps]

Is there a set of printed plans for the large scale cub.
What a nice looking plane, I have been in RC for years but got out of it when I started to fly a Powered Parachute but seeing that I am getting older and retired and thinking I might have to give that up and I don't want to give up flying. When I was fly RC i built a BalsaUSA 1/4 scale cub which had a 108 inch wing span, I feel this is a good starting point.
Don

[nickademuss]

Their are measurements in this instructable, no plans per say. Just keep reading, its not like balsa were you build on prints, this is mush simpler.

Enjoy!

Oh this one will not fly like balsa, its heavy, it will fly like the real plane.

[donphipps]

Thanks, I noticed the dem. when I downloaded the plans. Looking forward to start building.

[Tweakster]

thanks again Zac for this Instructional

for other builders I sent Zac 20 bucks for a case of beer but he said he is using it for Hobbies, would be nice if others could do the same as I think The Great Brain of Planes deserves to have us pay for his Plane

Believe U me I appreciate this...

[nickademuss]

your the best mate Cheers!

[Tweakster]

so what is prop size?

[nickademuss]

it varies for whatever engine you use, but a 16x6 to 18x4 would be a good starting point, you want max rpm, so you may have to try a few to get it...

[donphipps]

trying to figure out how to download the plans to build the cub, need help
Don

[nickademuss]

you should see a .pdf icon at the top click on it and it will let you download, if your a member....

[Mr.NHRA]

This is very nice. Did you train to fly on a simulator? If so which one? I am just getting started in model air planes and I want to know the basics before I go and crash a plane. Thanks.

[nickademuss]

I am self taught, I used a very crash resistant airplane to learn on, the Air Core Trainer, and I started out with FMS the free simulator. My Dad got me a cable to connect my radio to the PC and I got my bearings that way. I crashed the trainer a few times and lost more than one propeller but it kept on flying. I have also uses Aerofly a cheap alternative to RealFlight.

[babylon5]

Wow nickademuss I admit you are really into RC.
Few RC flyer self taught rarely succeed because they would have crash so many times during their learning curve and usually give up half way.
Nice Piper cub!
I love coroplast aircraft and have design a few usually electric.

This one is a scratch built racer at

http://www.youtube.com/watch?v=1_n7KA5jD80

Cheers

[nickademuss]

Thanks! If I flew balsa at the start I would of gave up.... but plastic lives to fly again and again!

[randallpw]

I had the aircore 40, great little trainer, Very relaxing to fly

[nickademuss]

good aircraft, I had one of those and now have a colt

[finnrambo]

        Im surprised you could start on nitro i still have difficulty flying my super cub with act off , anyways just curios but why is nitro harder to learn than electric anyway?

[Kelticpaddler]

Heh, when I started flying, there was only methanol (nitro) and diesel engines.

You adjusted the compression of the diesel with a lever on the top of the cylinder.

Absolute b&&$er to start by hand!!

[finnrambo]

lol yeah I have nitro now....... you can hear me cursing across the parking lot when the battery on my starter dies.....

[finnrambo]

 the nextar select rtr is the best ever

[finnrambo]

where do you buy Aerofly anyway never herd of it

[nickademuss]

just do a search, its out there, free on some download site, their is also FMS, its free as well, just google...

[Mr.NHRA]

That is really cool. Thanks for the help.

[nickademuss]

Your Welcome

[Ferguson199]

Awesome plane, The only thing I don't like are the tail feathers, they don't quite look like the real t thing.

About a month ago I started building a super cub (haven't seen this post until now) out of 4mm coroplast. Haven't finished it yet but i'll be putting my O.S. 70 four stroke in it.

[nickademuss]

good thing about the plastic is that you can cut it any way you want :) Mine looked more to scale but it was tail heavy, I had to trim some off to get it to balance....

[Tweakster]

Nice Plane I'm in build process now, if I lived in your town I'd drop U a case of beer,

Thanks nice plane, I did a slight modification to Aztec

[nickademuss]

Thanks man, I would like that

[dmlong]

will using the stock muffler on the engine work ok, or do I have to buy or make a new one for it?

[itri45]

I may build this but want tto know what specific servos u used also im on a tight budget so anything that i can make on my own for cheaper i will.
any advice would be great
by the way it is an amazing plane
great work

[itri45]

Also could you post a link for the battery you used for this

[bvdc]

its a raily nice aireplane