old git

I am wondering about this motor, ZENOAH G380PU 38 for a 1/3 scale J 3. Any advice, warnings etc cheerfully accepted.

I have no experience with this size of motor. Extensive with m/cycles and cars but no idea of relative merits of gas engines for models.

Thanks,

Old git.

Dr1Driver

Balsa USA recommends a 30-50 cc for their 1/3 Cub. The G-38 is almost in the middle of this range, and will probably fly your Cub in a very scale manner. Remember to build in lightness wherever possible. The G-38 has no bad habits and is very user-friendly. I highly recommend Zenoah. Gasoline engines are very reliable and user-friendly. Once broken in, they seldom need adjusting. They don't flame out in the air like glow engines might do. They are very economical to run, too. Gas engines do tend to be heavy, but it beats dead weight if your plane is tail heavy.

Dr.1

Floater-RCU

Hi old git,
I have the G38 in my 1/4 scale Super Cub and love it. A fellow that I know has the Balsa USA 1/3 scale Super Cub which he powers with the G62. (See Pic) His plane does fly very scale like on floats and slightly more spiritedly on wheels. Going by the performance of these planes I would not go with less than the G62 in the 1/3 scale. Either way Zenoah makes a great engine. Pic #2 is me and my cub several years and many flights ago.

Floater

Dr1Driver

Yea, Floater, I wondered about it after I wrote my reply. BUSA says their plane weighs over 30 pounds. Even with a wing like the Cub has, that's a lot for a G-38 to pull.

Dr.1

old git

Thanks Dr1ver & Floater for your replies,

It sounds very +ve, now to risk money on the motor. It's a great resource to be able to seek advice while sitting at home, the quick replies are much appreciated as is the advice.


old git.

P.S. I like the colour scheme on the 1/4 scale cub (I thought they all had to be yellow!)

old git

Hi there Dr1driver & floater,

I did it, I went ahead and bought a Zenoah G-38 on eBay, new from a super seller. They sell many many new motors both to UK home and at home in Texas. The seller had 7000 plus +ve feedback so I used "Buy it Now" and looked at payment options. With credit card in hand I waited until 3pm UK time to hit the 9am US time, the time the shop opened. Right on the nail, five minutes later it showed paid on my computer and all I have to do now is wait a few days and hope the revenuers don't catch up on it and charge me customs duty.

I find it more than faintly ironic that I can ask for advice sitting at home in front of a computer and act on it to buy a Japanese product more easily than I can in the local hobby shop. It is only because of the size of the US economy that any of these type of products are available at affordable prices.

Thanks eBay, RCU and its members.

Regards,



old git

P.S. I have also bought a considerable amount of American made goods.

shakeelsid

Hi Oldie
I can only speak of what I know from personal experience, I built a couple of scratch built 3rd scale cubs from factory drawings a few years ago. Both came out around 30 lbs and powered by G-62 running 22-8ish props. What do you want your cub to do - mine were marginal performers. If I built them again now, I would probably put in G-80 boxer minimum, and throttle back to 3500 RPM for a very scale like flyby. considering there is a fractional difference in weight of all these motors, excess power is always good, you can throttle back and relax that even if your motor did sputter (they do) and lose power, you can safely keep flying.
cheerios
sid.

old git

Hi shakeelsid,

I've bought the engine now. My flying skill are greatly outmatched by my building skills. I love to build but when I last flew it was many many years ago and I was an extremely poor pilot then.

My most recent history is as follows.

I built a Sr Falcon and fitted an OS 58, both bought new. The Falcon flew well until I fed in full up in panic at full throttle. The wings lifted off the seat and the tank cover (held by bands) snapped down under the leading edge. The model now had about 3/8" under the leading edge at full throttle. The PILOT next to me took the Xmtr from me (the model was looping continuously) and brought it down (after closing the throttle) in a huge stall using rudder only. He said the ailerons were inoperative DUE TO THE STALL. The model was undamaged so I put it away and built a Super 60 from plans. I never got very good with it and then work became too pressing. I am now back to modelling and have a number of models to build. I expect the J-3 to be a long term project built concurrently with all the vintage jobs that are lined up. With any luck I will have skill enough to fly the 1/3 J-3 eventually.

I am rather keen to get on with playing with sparkers, I have a number of them. The G-38 will be another of my toys and I hope it will not be too heavy for a 1/4 scale J-3 either.

Thanks,

old git.

shakeelsid

Hi Oldie
Sorry, I didnt read the full thread and thus was ashamedly unaware that you had aready bought the engine - Its a good engine, runs well and reliablish - bit of undersiable fat, considering a comparable RCV with electronic start would be much lighter. I know my opinion is skewed because these days I am only fancying engines which are suitable for all out 3D and relaible engough to torque roll a model at 3 ft for ever.
I had a great craic converting 2strokes for while, did a 120 cc Italian industrial pump engine to make a 7 lb 12 hp monster, which was quite punny for my 24 ft span 120 lb single place ultralight - did fly though.
Forget about flying skills, we are all humans and are not supposed to fly. My last model flight was a week ago and the airplane is still lodged safely at the top of a 110 ft tree - Beat that!
Cubs are wonderfully easy to fly, and the bigger the better. My first 1/3rd cub was only the fifth model I ever flew, and I took it out to my local field on weekday morning for a test flight - havnt looked back since. There have been crashes, and this one lost in the tree, but I build very quick and very much - so have a good supply.
Do keep us posted

GerKonig

I fly a 1/4 scale J-3 Balsa USA converted to Super Cub using a Quadra 42, w/o problems:-) All the 1/3 scale Balsa USA cubs and supercubs I saw were powered by G-62. Well not all, I saw one powered by a 2 cil. 100, it was unreal the acrobatics this guy did with this huge monster, at no more than a few feets from the ground:-) Scale? no, Fun? Well, it was a pleasure just to watch, imagine to fly the thing:-)

Gerry

shakeelsid

vow, now you are speaking my language - I have been having these urges lately to put a 3W 120 on a 1/3rd scale cub - isnt that fun. As I said, you can always takeoff at around idle power, sputter around at 2500 RMP - very very scale, noise and all. Then on a low pass, bleed off all the speed in a long flare before adding full throttle and up elevator - torque roll it right in front of the pit area - beats the hell out of the crowd. There is this video of a large 1/4 scale Coro Cub at SPAD page - well its not cub, but its a lot of fun.