Sig Skyray

NEW222 wrote:The Skyray sure is a looker. Great job on it!

Thanks appreciate the comment.

That OS FP .25 is for what size plane ? i know there is a 1/2A ,.15 and .35 version . Just wondering i am thinking of a .15 size ?

Sig also made the Skyray .35 which is a 44" wingspan.

Ken Cook wrote:               Sig also  made the Skyray .35 which is a 44" wingspan.

This is the .35 with the 44' WS.

I knew what plane it was, I was answering to Eric's comment in regards to the size

OK thanks i was just wondering and i would like to know how it does with the .25 OS on it as beeing underpowered ... Low and slow for me but i want to go round without the fall down from my HIP can't keep up at the end. LOL

Ken Cook wrote:             I knew what plane it was, I was answering to Eric's comment in regards to the size

Sorry ken i thought you would,  i was thinking that you would know that when I read your comment. I didn't catch Eric's comments.

Eric, OS made a few types of .25's. The least powerful of the bunch would be the MAX .25. This can be confusing due to OS using the MAX designation on most of their engines. This engine is a baffled iron piston in a steel liner. These were also I believe the last of the strap on muffler styled engines.
How you prop the engine is according on how you want to fly. While a bunch on the internet make certain claims to how overpowering a FP .25 is for a nostalgic profile, we fly them all the time with these engines. Don't use more than a 4 pitch prop and let the engine just spin away. My foamie combat wings are 460 square inches at about 26 ounces, a FP .25 pulls those planes around with authority. However, I can fly them in a stunt like manner if need be equally. These engines can also be easily regulated by the venturi size. You want more power, open it up, and vice versa.

Thanks Ken , seems to be a very versatile engine as to tune it the way you want to fly , I guess that they last really well with good care .

The early late 60's-70's MAX-S engines were very well built engines for the price. As times became more competitive, OS introduced the FSR engines. These in my opinion were the best engines OS every made. True chrome liners, high quality produced engines. The FP series even though were extremely well made, didn't quite offer the power of the FSR line. OS offered the SF and SR version 25's in and around the same time of introduction and they were essentially built around the FSR design. The FP and LA engines are what I was referring to in terms of flyability. Several parts interchange and both engines have very close similarities. One problem with the FP and LA engines is when mounted on a profile, the wrist pin end pads wear out and this could cause some serious scoring in the cylinder if not watched. Those end pads are not available unless you buy the whole wrist pin. In the winter, one of our members makes these end pads from graphite impregnated Delrin which lasts longer than the Teflon pads. However, he hasn't done so lately. I have growing concerns for a few of mine.

Question ken cook After reading I have a os myself .35 max modified wit enya parts Those end pads are not available for the piston pin the wrist pin end pads how To Find this ?? Parts I would like to put this engine back to work it is in very good condition I do not use them Because of that parts This pieces Can still be used but after the modifications made to this engine it is now extremely efficient with an excessive rpm I'm really scared to destroy it if that parts wear out completely

Most OS MAX parts are long out of production. My suggestion would be to try and see if a substitute would work such as a LA or FP wrist pin end pad. If not, buying Teflon dowel rod and turning your own is the only solution.