KidVermin

My Feedback: (3)

Experts Needed :

Tonite I traded for a scratch built 42% Cub without an engine. The
plane is covered with fabric and just needs a repaint. Never been
flown. Estimated weight is 40 lbs. 15 ft span 9'-6" length 3 ft. to
top of wing. This looks rather large in my living room, but they all
do till you get them to the field.
What would be you best guess on engine and prop for this THING? I've only messed with the little 1/3 scale stuff.

Thanks:
Randy

rcavi8ter

My Feedback: (19)

I would go with a G-62 or maybe a brison 4.2. I had a ST3000 in my 1/3 and it was awsome. It looked and sounded so real in the air. To many people overpowering these birds now. Go with something that will make it fly scale like.


Chris Puckett

KidVermin

My Feedback: (3)

Chris:

The only big Cub I could use for reference was the Balsa USA 1/3
scale at 30 to 35 lbs. So I guess maybe 10 lbs. more, the G-62
should pull it around. It is just so huge that it had me questioning
if my 62 would even lift it off the ground. When I held a 22 x 10
prop to the nose it just seemed too small. Sorta like a 20" prop
on a Mr. Mulligan where there are only a couple of inches of prop
outside the cowl.

Jim Messer

My Feedback: (2)

Hi Randy:

Your Cub sounds like it will be a lor of fun for you. I have a 1/3 scale J-3, and a 1/3 scale J-4E (12 ft. span) that I designed myself, and they are powered by G-62's swinging 24 x 8 props. Both weigh about 30 lbs., and there is lots of power. However, I don't think that a G-62 would be anywhere enough for your big bird.

I also have a 30% scale Stinson SR-10 (13.5 ft span) that I designed myself, and it is powered by a Fox 5.8 swinging a 26 x 10 prop. It weighs 45 lbs. and this engine flies it with authority.

Now - here's my rule for what it's worth: For each one-tenth cubic inch of displacement, you can fly one pound of airplane. Thus, for a G-62 (3.7 cu. in.) - you can fly up to 37 lbs. With my Fox 5.8 I would consider up to 58 lbs., but those are absolute limits with no power reserve.

I also try to go by the prop. A full scale J-3 has a 72" prop, therefore a 1/3 scale model should use a 24" prop, which it is in my case. If your airplane only weighs 40 lbs., it is very light for its size, and you could probably get by with a 26 x 10 prop. However, if it turns out to be a lot heavier - with engine installed, etc., then you are going to require an engine that will swing a 28 x 8 prop - and that gets you to the big twins.

How much money do you want to spend? The Fox 5.8 is a darn good engine for the buck; a twin will cost you a lot more.

Hope that this will help you in making your decision.

KidVermin

My Feedback: (3)

Chis & Jim:
Thank you for the input. I'm going to reserve my engine decision
till I repaint and fit on the 2 x 4 wing struts. That will give me the
exact weight or closer than what I'm estimating now. I was
afraid I was at the limits of a 3.7, but would still fly on a calm day.

Homebrewer

My Feedback: (8)

There's a 1/2 scale Piper Cub on the following website (its for sale). The owner powered it with a Q100.

http://www.rcexchange.com/html/catalog.html

You can check out the Quadra Engines at this site:
http://www.quadraaerrow.com/page7.html

Good luck with it.

JCat

Quarda 100cc the only affordable way to fly here. Good luck.

Giant Scale

rreis,
If it was me I'd go for something in the 100-150cc range. This should give you plenty of power to perform maneuvers and provide a safety margin. A G-62 will fly a plane in the 25lb range but aerobatic performance would be marginal. I understand that this is a scale application but I'd rather have power to spare than not enough power.

CAPtain232

My Feedback: (40)

This would truely be a great match for the ZDZ 80 single. Many have used this engine on 1/3 scale aerobatic planes with good results. There is absolutely no doubt in my mind this would be a good lower dollar high performance match.

Jeff

KidVermin

My Feedback: (3)

Thanks for the input guys. Right after I started on the Cub, I had
an oh-no with my laser and decided on a revamp of my air-trax.
I've got a lead on a G-445, but the 100 & 150's are out of reach
with my budget. This is going to take some extra thought if I can
do the Cub justice with what I can afford.
Thanks again:
Randy

rcavi8ter

My Feedback: (19)

I know the solution to all your Cub worries. Sell it to me. I will find a motor for it. No really you might want to look at the ZDZ 120 twin it is a fairly inexpensive motor pu very high in quality.
This is a Cub and it needs to fly on the wing like the real plane to look pretty. That is what I loved about my 1/3 with the ST3000 in it. A little 1.8 cube motor pulling a 36lbs plane around.

Chris Puckett

gone.

I read with interest everybody's reply to Randy's purchase particularly the ideas on weight vs engine size. I built a Nosen Mulligan and powered it with a US Engine 41cc and it flew very scale like @ 22 lbs with a 20 x 8 prop. I tried a 20 x 6 on it once and there wasn't enough runway to get it up. That same engine is now on a 1/3 scale Pober Pixie weighing in at 30 lbs. The wing area is a bit more than the Mulligan being a parasol wing and all and the wing loading came out to about the same as the Mulligan. The Pixie flys very scale like although a bit more power would be nice to pull her through the loops with a bit more ease. I'm still using the 20 x 8 prop. Now how does that help with the engine to use on the 40 lb Cub - I'm not sure. Good Luck Randy !

Dean

Forgues Research

My Feedback: (7)

Randy,
For what it's worth, the very first 1/3 scale Cub, if anybody remembers, was by Bob Nelitz (true scale) it had 12 feet wingspan, and weighed 30 lbs. It was powered by a Quadra 35.
It was the most scale like flying I had ever witnessed. We all tend to over power.
The plane you described should be perfect for the G-62. You can even use a 28" prop with a smaller pitch.

bpryor

My Feedback: (45)

Hi Randy,

I just sold a 40% Aeronca Sedan that had a Precision Eagle 5.8 in it, a very similar motor to a Brison 5.8. Although I never flew it, I did have a video with it flying and it was very "scale" in performance....though the plane did weigh over 90 lbs thanks to all the counter-weight required to balance a scale plane of this type. I personally would put more motor in it to have some reserve available. You can always fly with partial throttle for scale performance, but still have that extra power available for emergencies. Personally I wouldn't put anything in it smaller than a 100.