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HelicopterMain Discussion › 4 stroke applications
06-02-2004 03:18 AM  13 years agoPost 1
painly

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sasaktoon, sk, canada

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i have a saito 91 4 stroker sitting around (hes watching tv right now), how would this motor work in a 60 size application? has anyone done it? 4 strokes like a steady rpm and have lots of torque, wouldnt this translate if geared properly into a really well suited 3d machine, with almost no bogging?

any opinions appreciated.

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06-02-2004 03:39 AM  13 years agoPost 2
painly

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sasaktoon, sk, canada

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ya i had it in my ucando 3d till i got a bit to adventuresome.

i think this engine has spent about half its life hovering anyways, maybe it just really want to be in a heli

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06-02-2004 03:52 AM  13 years agoPost 3
Gearhead

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Vt

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I believe MA made a 90 size 4 stroke heli, yes it's all in the gearing and blade size.


Jim

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06-02-2004 03:55 AM  13 years agoPost 4
Phil Cole

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Menlo Park CA

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There used to be a version of the X-Cell SE that used a YS 91 ACH four stroke. I don't really know what was different about the the 'H' version of the YS 91, except that the crank may be longer to accommodate the fan hub.

The four-stroke SEs fly about the same as the two-stroke 60 size SEs, but without the two-stroke noise. I don't think they really cut it as a 3-D machine, but are OK for F3C flying.

Gearing will need to change, and the Saito probably doesn't have quite the power of a YS.
You'll need to come up with an adapter for the fan.

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06-02-2004 06:01 PM  13 years agoPost 5
tim tompkins

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Boston, Georgia sw Ga. Thomas County

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Fuel cooling

We use a lot of fuel for cooling in our helicopters.Four stroke motors don't get the benifit of crankcase flushing like a two stoke.All the smaller four stroke models from the past needed to be leaned to the limit just to get into a hover.I flew a MA s/e 91 ys four stroke last month.It is way cool novelty,cool sound and plenty of power for good flights.With a GV-1 to avoid the valve float and the correct gearing it is similar to a good 60 2 stroke.The cost for the supercharged and helicopter preped ys was more than twice that of a 60 2s.They also require a special muffler made by hatori.The whole pkg.seemed far too much money to risk.The owner then wrecked it just like an ordinary model until he added up the cost.It is probably for sale. TimT

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06-02-2004 06:09 PM  13 years agoPost 6
sharam

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Northern California - Fly at Morgan Hill Field

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Bergen also made a 4 stroke heli version of its Intrepid. I had one and it flew very nicely with a YS 91 ACH. But, it really wasn't a 3 D machine - a bit too sluggish. I still have the YS 91 ACH sitting in my workshop!

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