MHester

My Feedback: (1)

ok, strange question here.

I'm building a Curare for SPA (and to play with mosty). I don't like 4 strokes, and I am looking for the most powerful .60 sized 2 stroke I can find. I have seen a couple jetts run and I am way beyond impressed. So here's the questions.

I'm looking for a good combination of speed and power...and speed. Heh. What would be a good prop and how would it turn?

If I couldn't use a pipe how would it run?

How finicky is it on fuel draw (attitude etc, this is a pattern plane)

What would be the best exhaust set up if the rules state "Must use a proper muffler, but no tuned pipes are allowed" (expansion style mufflers are legal)

Or am I just out of my mind and should really forget it or get a 4 stroke?

Thanks,
Mike

bob27s

My Feedback: (19)

Hi,

Thank you for writing.

Having flown pattern back in the late 70's until the early 90's I am fairly familiar with the Curare

First off, the 60L is actually a '40' size engine. The difference between it and the 40-46-50 is that it is designed to turn lower RPM, and is basically a derivative of the 60 CL stunt engine.

If you can build the Curare to weigh in less than 6.5 lbs, and still get it to balance with the smaller engine up front... You could indeed use either the 50 (faster with an 10.5 x 6 @ 16,500 rpm) or 60L (slower with an 11x6 @ 15,000).

I am familiar with the SPA rules from when I lived in Atlanta, and if I recall they still have a .61 cuin displacement rule. As for the muffler, the jett stream muffler is not a 'pipe' per say, but does increase performance. I believe it is legal, but you would have to check.

Jett does make a 'big block' .61 on special order. You may want to email him to see if there are any parts on hand, and what his current price is. It is pretty much the same engine as the .65 and .76 he builds, but he gets little call for it. Email him at [email protected] to check on availability.

If you can go over on engine size....

For your use with the Curare, I would recommend going with the SJ-76 or 90L. Both of these are conventional '60' size engines with much more power than the old OS 61 FSR engine I use to fly way back when. With the Jett-Stream muffler provided with either engine, you will have a much more powerful system than the 61 fsr with a full pipe ever could attain.

Keep in mind, the 61, 76 and 90L are designed for RPM. With either engine turning a 11x8 or 12x6 prop, you will have both the speed and power you desire.

I hope this was helpful.

Bob Brassell

MHester

My Feedback: (1)

Thanks fo the reply!

Yes the Jett stream muffler is legal.

I suppose I'll have to go with the .61. Unless I could get Dub to make me a 90 L and print ".61" on the case =P teehee. I know, I'm terrible.

-Mike