I have an OS 50 Hyper laying around and I am thinking about putting it on a future plane project, would it be ok to use a heli motor on a plane? What muffler would be good for this motor for aircraft use?
Thanks

The only problem will be with the carb. The helicopter carb will be too rich around half throttle. Otherwise it would be a great airplane engine.

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I have no experience with your particular engine, so Kweasel may be right. He usually is.

I flew competition fun fly models some years ago. Locally, the hottest flyer (Halverson) was flying an OS .32F-H ringed engine. After watching his efforts and the effort of others, the choice came down to either this engine or a Webra .32 GT or Speed, I forget which.

The Webra was in stock nowhere, so I bought the OS heli engine. We were running 11x4 Rev-Up props when we could find them, which represents a hefty load for a little .32.

My OS powered my Florio Stunt Wagon first and then lighter models later. It was one of the best airplane engines that I have ever owned. It laughed at the extra heat generated by performing multiple high stress maneuvers. Other folks using conventional airplane engines would sometimes have problems with overheating. Not the OS heli engine.

So, at least in this application, the heli engine actually provided an advantage. I also sport flew the engine and never had a problem relating to the extra heat dissipation capacity of the heli head. It performed as a normal airplane engine would perform.

Are the engines set up differently today for more nitro? I don't know. They were using pretty heft amounts of nitro back then too. Personally, I don't think you will have any problems with using this engine in an airplane.


Ed Cregger

I have run in a couple of heli engines in planes no problems with the carb or anything else. In one case I needed a different prop driver.

Go for it. I think it will be fine.

The only drawback is the length of the crank shaft and the fact that the hyper doesnt ship with the woodruff key and thrust washer.

The carb will be fine.

All of the .30 sized heli engines seem to work equally well as an airplane engine. Most of the older 40-50-60 heli engines worked well too. The newer generation of heli carbs have been designed for a good rich flight idle on high nitro fuel. To make matters worse most heli carbs are bigger than their airplane equivalent. I have not tried the most modern .30s but I did try the newer OS 50sx-h and it was horribly rich around half throttle when used on an airplane with low nitro fuel.

KillerG, try the engine out, in the interests of science. From memory (correct me if I'm wrong) the Hyper has a three needle carb, so mid range should be discreetly adjustable.

The Tower .46 muffler (or any OS .46 and clone muffler for that matter) should bolt straight up to that engine.

If you go ahead, try an APC 11x6 or an APC 12.25 x 3.75 out and get a tach reading. Let's see if she can get into the 13-14k region!

Keep us posted.

Hyper has a 2 needle carb.

I have fitted the OS hyper 50 helicarb to my OS 91 fx. The carb is one big ***** ***** and actually have a 10mm venturi. Stock 91 fx is 9.5mm. On my teststand it seemed to spit alot of fuel in midrange even though I have leaned the low needle all the way (it is only possible to turn the low needle 90 degrees either way) I just finished a new plane fitted with this particulare engine so if the weather allows I will give it a shot this weekend to see how it performs in flight. I would suspect that a 50 engine with this HUGE carb on an airplane would experience even richer midrange than my 91 fx

I have decided to sctatch the idea of the heli motor, and are going to try the new 55AX fro OS
Thanks for the input guys.

So it is (I knew I should have checked...).

Thanks

KillerG, remember to report back with tach readings on that .55!

Heli engines work fine on fixed wing. Keep in mind, many of the specialized helicopter engines feature higher port timing - lower torque, higher rpm engines.

If you use a tuned exhaust on it, and do not over-prop the engine, it can really perform well.

A good example is shown here.... photo is an old OS70H engine - really comes to life with the tuned muffler and 11x8 prop.

The hyper 50 can be combined VERY well with a Jett-Stream tuned muffler, or similarly with an Ultra-Thrust muffler (same type of animal). Easy bolt on installation.

You can also pick up tuned pipe system from MACS, the pre-tuned .46 size pipe will perform well.

Point here, although the engine will run ok if you hang a standard OS stock muffler on it, it will perform extraordinarly better with a tuned exhaust.

You would want to use nothing larger than a 10x6 prop at first - let the engine turn up. In other words, it will make a wonderful sport/speed engine - but do not expect it to be as useful as a 3D or scale engine

(of note, the rich midrange is actually a good thing - somewhat useful when staging up and down off a tuned exhaust - and it can be accomodated a bit more with glow plug selection)

I hope this is helpful.

Bob

bob27s
That is what I am looking for is FAST. I do have a muffler like the one in the picture (mine is silver in color) on that OS50, but I wasn't sure what it is. I aquired it through someone who passed away and not sure what it is. It was bolted on to a YS-45. Any info on it.

If it is silver in color, and looks the same (exhaust exits the END, not down or to the side) it is probably Ultra-Thrust (nelson) muffler. That will work great... bolt it to the hyper 50 and give it a try. You might want to try a 9x8 prop along with the 10x6 at first - get a baseline rpm to see where you are. You want to target somewhere between 16,000 and 17,500 rpm with your prop selection.

If the muffler exits side/down and/or has a long bolt running through it for assembly, then it is not a true tuned muffler (one of the Tower .46 type mufflers - inadvertently semi-tuned).

Yep that is it. Now is there anyway to tell the difference between the standard and the racing versions and long? Mine is for the os46 size and is 6 1/4 from exhaust tip to mounting flange.

If someone bought it for the YS45, it is likely the standard version. Rare that engine was set up for turning much over 16,000 - 17,000 rpm. Same goes for the OS.46.

Dave Shadel in the engine mfgs forum (YS support) can give you specifics if you have the dimensions.

Today I had a chance to run my tuned 91 fx. It is fitted with a carb from that very OS 50 hyper heli engine and a Tower 75 muffler plus some sleeve work. I ran 0% fuel and a Rossi R2 hot plug and a MAS scimit. 14-6 prop. I was very anxious about how it would perform and if it would have a rich midrange. Well it ran great, screamed on top and idle was so low the plane just stood there jumping up and down so I had to raise the idle rpm just a bit. I let it idle for a long time and stabbed the throttle and the engine picked up almost instantly. I ran it in the midrange for some time and it was the same story. To sum it up the engine ran absolutely beautiful even at no nitro whatsoever. I wasn`t able to tach it because I was indoor due to BAD weather and my tach don`t work without good daylight. I have tached this combination before on 15% and got 12500 rpm on that MAS scimitare 14-6. All I have done to the helicarb is to lean the lowend as much as it allows (90 degrees) and set the highend needle. Based on this I would say that a heliengine could be made to power a plane, or atleast that it will not be the carb to hinder that