ChinookPilot

As a "new to helicopter" person, I would like to know if there is any manufacturer that makes a 4 stroke 60 size helicopter. The only drawback for me to getting into todays helicopters are those blasted 2 stroke engines that make a most annoying racket. I want something that sounds more scale. I fly mostly 4 stroke and gas airplanes and their exhause note is much more pleasing and scale-like.

Thanks for your comments!

Sam

GM1

Funny, I find gas motors to be the most annoying and a well muffled 2 stroke heli to be very quiet and tractable.
I ran a YS 91 ACH in an X-Cell graphite SE for a couple of years and liked it a lot but though it required much less fuel, it had its own problems. The motor runs hotter and it requires a governor to keep from over revving in aerobatics. The 91 performed well, was fuel efficient, and was very smooth but had nowhere near the performance of the new YS 80 2 stroke or OS and YS 91 2 strokes.
Gordie

radigan-RCU

My Feedback: (5)

I was actually wondering the same thing. I have an OS .40 FS car engine and was thinking of putting it into a raptor 30. Anyone ever attempted this?

Ron

maxman

Try this: http://www.rcuniverse.com/showthread...545&forumid=23

with a link to some pictures of a YS53 in a Raptor 30, also..

radigan-RCU

My Feedback: (5)

Just to fan the flames a little, the O.S. FS-40S-C w/40P Carb has the following specs.


SPECS: Displacement: 6.49cc (0.396 cu in)
Bore: 21.2mm (0.835")
Stroke: 18.4mm (0.72")
Output 0.9 bhp @ 17,500 rpm
Practical rpm range: 3,000 - 21,000 rpm
Weight: 323.5g (11.41 oz)

The OS .32 SX-H has the following specs

SPECS: Displacement: .319 cu.in.
Bore: .768 in.
Stroke: .689 in.
RPM range: 2,000-22,000 rpm
Output: 1.2 hp / 18,000 rpm
Weight: 10.23 oz.

The RPM is very close giving that OS put heavier valve springs on the car engine to help combat valve floating. The HP is down a little but I am thinking (warning, warning, this is where things go wrong!!!) that the added torque would allow it to run sufficient for mild flying. Let me know what you guys think.

By the way, I am in the middle of putting the OS FS .40 on my Tmaxx. It would already be there but I broke a tap in a mounting hole and have been wrestling with it! It took a couple of hours to make the mount so I haven't pitched it yet to start over.

Ron

Dyehard

You are right in thinking there might be a problem with having slightly less HP. Actually, there is 25% less power, and a Raptor is not in the least overpowered with an OS 32. Most flyers put a tuned exhaust like the Weston Genisis on the .32 just to get adaquate power, and still wish they had more. Everyone who has tried putting OS .52 four strokes in 30 size helis has usually given up in frustration, they end up with a heli that just barely flies on a cold day and one that won't do even that on a hot day. A 40 four stroke will probably be even worse. The four strokes end up running wide open to barely get the job done, then they get hot and can't get the job done at all. The only helis that have worked with a four stroke engine have been the 60 size helis with a YS 90 ACH installed, and as Gordie pointed out, they had their problems. Good luck if you wish to continue the effort, but I would do a search on the forums first. After hearing of all the problems incountered, you might change your mind.