Here goes I am building a great planes 60 cub, I will at some point put it on floats, am I better off with a larger 4 stroke engine?

You'd better check with your local authorities.

I believe putting a 2-stroke in a Cub is illegal in most states (If it's not, it should be... Write your Congessman!)

But seriously, an os 91 or saito 100 would be ideal (whether you use floats or not)

I agree. A Cub with a 2 strike definitely should be illegal! [:@]

(Good recommendation on the size range to Mike, especially for floats.)
Dennis-

Hi,

Agreed, I am getting a used GP ARF Cub next week. It currently has a OS 46LA in it, and I am actively searching for a used 54 to 56 FS to put in it. I just can't imagine running a 2 stroke in a Cub. Do you guys think it is going to be too much of a problem sticking in a FS in the cub with the 46LA already installed. I guess I might need a new engine mount and drill a new hole for the throttle linkage, etc.

Matt

Chuck

I built a GP .60 Cub and put a Saito .91 on it. It looks great and sounds even better. I haven't put floats on it, but plan to. I think the .91 should be plenty of power, but don't know for sure. BTW, I didn't bother trying to use the plastic cowl that comes with the kit. I ordered a fiberglass one from Stan's Fibertech and am very pleased with it. I did use the plastic cowl to make a template to cut out the engine hole for my fiberglass cowl.

Matt-

I would consider a .70 4-stroke for that plane. Others may have other thoughts.

-Scott

M3_Matt, go with a 70 4-stroke, you'll be glad you did

If you use a two stroke in a Cub, I'm afraid you'll be banned from the Brotherhood of Cub Flyers until you repent

You don't want a power to weight ratio to do 3D stuff, so a .90 FS will do anything you want, with reserve power "just in case"....

Cheers!

Jim

whats so bad about a 2stroke?

Kinda like installing spinning wheel covers on a Ferrari - just ain't cool

Cheers!

Jim

Hi,

Well, I just bought a used OS 54 Surpass off ebay for my cub. I know it's at the min specs the GP recommends, but I am looking for more of a scale flight performance. Has anyone else flown their cub with a 54 or 56.


Matt

I fly my .40-size GP Cub (kit version, but very similar to their ARF I would assume) with a very old and very tired .48 4-stroke. It flies more like a real plane! Not much extra power for getting out of trouble, but more than sufficientfor cruising around slow and scale like........I usually fly at less than 1/2 throttle for normal flying, and often end up not too much above idle. You can't just punch the throttle and pitch up if you get in trouble, of course, but hey that helps you improve your skills I guess. I found myself applying *less* than full power the other day after a touch-and-go in a small grass area surrounded by corn, I had botched the landing a little bit and the plane was heading toward a hangar. I don't know if I didn't have the presence of mind to apply full power, or if I "automatically" held off the power to keep the plane from going further left (it was heading left, and I think it was near stall and trying to drop the left wing just a bit).

You'll find yourself gingerely nudging the rudder and ailerons and using elevator sparingly in low-speed, low altitude situations to keep the plane from stalling/snapping, at least I do with the control throws and limited power of my Cub.........great fun though!!!!!!

-Matt Bailey

It's kinda like putting a Kawasaki engine on a Harley

Yeah, who'd want the thing to actually run?


R

I like both analogies.

I fly my 80" wingspan Cub with a 52 four stroke and like Matt said, it flys like the real airplane.

I was out with it on Sunday and the wind was gusting all over the place, with max gusts of 15 according to local weather. There were a couple guys flying 3D planes that thought I was either brave or nuts, but I was still able to chug around the sky at 1/2 throttle. (Just had to play the ailerons and rudder like a madman! )

Take offs weren't my best with 90 degree gusting crosswinds, but my landings were real nice. All that rudder practice DOES pay off!
Dennis-

Hey Minn, anything but those obnoxious, rattly, noisey weak kneed vee twins. Good lord I HATE that sound. I preferr the sound of a strong small block v-8 turnin 8 grand. Oh well we all have our personal pecadillo's.

Mark Shuman

As long as you remove the LA first it shouldn't be a problem. Check your CG before you fly.

Lachlan

Yea, that would be a good idea. I ordered a O.S. motor from Tower that is pre drilled to make the installation a little easier. The only thing that I am worried about is the location of the throttle cable from the 46LA to the new 54 FS. It looks like the old owner of the 54 already reversed the carb. I am picking up the cub tomorrow, so I will let you guys know how much pain I go thru making the swap.

Matt

Matt,

Make it easy on yourself and before changing the throttle pushrod routing check out the little Dubro 4-stroke throttle linkage. It goes on the side of the engine mount and lets you use an offset throttle pushrod with the 4 stroke carb. Neat little gadget consisting of a ball link and a sort-of offset bellcrank. If I remember right they are only about 3 or 4 bucks at the LHS.

Duke

Fourstroke is the ONLY way to go with a Cub. If you go two-stroke, fly alone because you'll kill yourself if you ever see/hear a fourstroke Cub. I think a 54 is fine with the Cub but it would be TOO scale. It's not bad to have a little more power... seems to come in handy just when you need it. If you are looking for a budget fourstroker, the Magnum 61RFS or 70RFS are not bad. I had a 61RFS in an 8lb .40 size Cessna and it was fine. I think the GP cub is around the same weight with even larger wings. Of course, if you haven't budget limitations, I'd recommend a Saito 90 or 100 Twin. That would be absolutely tasty. If you do go with the Saito, you must post pictures!!!

Ya know I don't find real aircraft sound anywhere near a 4-stroke RC engine. I've never heard a real plane make that RC 4C thumping sound. In fact the 2-stroke sound is closer to real IMO. Having said that I'm putting a 4C on my new Cub. Besides practical reasons it seems like it's just the hip-cool thing to do.

Your opinion is WRONG! Spending as much time as I do at the local Class D airport, I have not been too fooled by any of the "real" airplanes making me think that a big 2-stroke engine was taxiing, taking off, or flying by! I have heard some small planes that fall into the Experimental class that sound like giant glow-powered four strokes, though. It really all comes down to what you like and how it sounds. If the sound is worth that kind of moolah to you, then you spend it and smile. If not, then a buzzing 2-stroke is what we end up with. I only own one 2-stroke, but have three 4-strokes. I like how they idle, transition quickly, slow down quickly, and especially the sound. Not to mention the extra torque to turn a bigger prop a little slower than a 2-stroke, which helps with prop tip noise. And the fuel economy, reliability, etc. It's the variety that makes R/C so much fun.

Lachlan

I agree about putting the 2 stroke in a cub.. It really should be Illegal! BTW I know a guy with a 40 sized clipped wing cub and a O.S.(I believe) .91 in it! He 3D's that thing That too should be Illegal!

Well I flew the cub today for the first time and she flew just wonderful with the O.S. 52 Surpass.
I was a little nervous at first since I have read a lot of people saying how touchy cub are on takeoff. It takes off wtih half throttle and fly great at 1/4 throttle. I have increased the throw on my rudder since I feel I didn't have the greatest rudder authority on takeoff. I have always loved the cub and I think the GP ARF is the plane I will keep for a long while.

Matt[