OS .61fx or Super Tigre G90 for twin project?
 

Hi all, I'm in the process of building a Duellist 2/60, and am still trying to figure out which of these engines to use. I have a pair of G90s that are new in the box, along with some used ones for backup. I have five of the OS .61fx engines that are all used to one degree or another. I looked up the specs for these engines, and it seems that they are only about an ounce apart in weight, and both show the same range of props.

I'm leaning toward the ST90s, as I have a new pair of them, and I also can run my home-brewed 0% nitro fuel, although I was saving them for a C-46 project that is waiting in the wings. The OS engines have a great reputation, and I'm happy with the one that I've been running for about 15 years now.

I welcome any thoughts, what do you all think?

I dont have the Os;s but have the ST90 . Its a fuss free good engine as Im sure the OS is . Dont let anyone say that the chinese ST ( if thats what u have ) arent any good . All my ST are chinese and are all good ( I have 5 ) .

The .90 is probably on par weight-wise with the .61s and makes more power. I'd opt for the .90s - you can always throttle back.

Or you could go with the one they still make parts for and hasn't gone out of business......

Better give those engines away to newcomers to the Hobby then.. Silly me.

Why would you give an engine with absolutely no parts or service support to a kid or a newcomer......?

Long Live OS MAX!!!!!!!

Ya, just give them to me, then I will have lots of spares. Not sure I need a .90, but you know... if it's free it's for me. The OP has spares too.

Can u get parts for that fx still ? New I mean from a shop .

well, he has 2 new 90s, do you need 2 ;)

Jim

No, but I'll pay shipping no problem. I got a fiberglass fuse Mustang that it would fit. Not my cup of tea, but I should finish it.

Any twin its important the engines work in sync throughout the throttle range. They must run reliably and should respond similar when called upon. Personally I would mount two engines on a single board at the same distance and position (inverted, vertical or horizontal) from each other as on the model, place the tanks the same distance and height from the engine. I would rig the throttle as on the model then run the engines until they run reliably throughout the throttle range. Do the same for the second pair then pick the pair that run the best and install them in your model.

Dennis

I saw a 90 inch RC B-17 with 4 OS 25s crash do to an outside engine flaming out,
the plane was a show quality plane with 2 Tx and 2 Rx and 14 servos, Guns move up & down, Turrets rotated and Bombs dropped of course, it was so well finished I asked the builders if it was plastic (I was still rather new to the hobby), some one said that was a complement ,
when one of the outside engines flamed out it rolled over and the nose dropped and went in, just like the full size B-17s you see in movies, it was a shame, but a scale crash

Jim

Some guys have problems adjusting the Supertiger carbs so that could be a problem with a twin. It should be flawless before you fly anyway. OS carbs are somewhat simpler according to some. Sometimes the KISS method is best. Keep it simple, safe (stupid) I hate to see a crash, but also hate to miss them.

ST carbs are easy to adjust if you read the instructions on how to set them up. No more complicated than a standard twin needle carb, just a different method is used.

one more adjustment the others don't have is rotating the spray bar to help smooth transition. Once set they are pretty well hands off. I believe Laser motors use the ST type carb.

As far as I know they use to and then went to irvine and now their own .

Well, due to a miscalculation I made when drilling the firewalls for the mounts, its going to have to be the OS engines on this one. It turns out the ST is a bit narrower at the mounting pads than the OS. I thought they were the same on my first look, but it seems I was mistaken. Oh well, I'm sure the OS choice will work out fine. Thanks for all the advice guys!