What seems to be the preference in SPA legal aircraft
as far as both 2 cycle & 4 cycle engines? ? ? ? ? ?

The OS .91 Surpass II 4 -stroke far outnumbers everything sles. I seems to have the best ciombination of power, reliability, durability, and ease of use. The Magnum is used as a lower cost alternative.

For two-strokes it varies.

Duane

a four stroke on a classic pattern? why not a diesel engine on a ferrari?

go to www.seniorpattern.com they have all the info you need,engine depends on if you are talking vintage pattern prior to 1967 or after. Pete

For what it is worth (my personal opinion), I think that 4-stroke engines should not be used at all. I think that only 2-strokes should be used. Only use the technology that was available at that time. That is one of the things that make them "Classic Pattern" planes. Just my 2 cents.

Yeah.

I think they dropped the ball when they allowed 4 strokes. The planes are modded to completely different designs to accommodate them. But no retracts are allowed? Inconsistant at best.

Terry in LP

The SPA is what it is. They've been around almost 20 years - plenty of 'stuff' has been written about their rules. The BPA was founded to provide an alternative to the SPA while allowing more modern designs, retracts, pipes, etc. You can run a 2-stroke 60 with any of the performance enhancing mufflers (like the one Performance Specialties sells)in the SPA. Technically. tuned pipes didn't really get popular in pattern until about 1977. Retracts were around well before 1975. The SPA was founded by a small number of pilots looking to simplify pattern competition. They achieved their goal successfully and the interest level continues to grow. The BPA will grow as well.
-Will

OK I' am a diehard 2 stroker, what brands are the most popular.
OS, Magnum, HP, Super Tiger, Thunder Tiger, K&B ?

BTW I just recieved my "King Altair" kit from Home & Hobby Solutions,
looking for a good engine for her.

Bill D.

a very good engine, easy to find and available since the seventies, the rossi 60 and 61.... pure classic pattern juice...

I agree on the 2 Stroke's, but I did not make the rule's. My preference OS61 SF.

Crank

The move to four strokes was precipitated by their use of a flying field where sound was a major consideration. A keep the noise down or don't fly situation.

Current production engines: Rossi. OS will be discontinuing their 61FX which leaves the 55AX or the 75AX. Do you want to compete in SPA events or just enjoy flying the airplane?

The RJL version of the Kraft 61 is a darn good engine.

Yes, I used the Kraft .61 in my Atlas with a pipe (back in the mid 80's) and that thing was a rocket!!!! Unlimited vertical performance.

Yes, I like my engines two stroke and with pipes. On top of that I like my aircraft best with trike gear that retracts.

Long live the...

Webra Speed 61!

Terry in LP

Here http://www.webra-austria.at/motor.ph...r=AERO&lang=EN
and here http://www.webra-austria.at/motor.ph...r=AERO&lang=EN

I will probably just enjoy flying the airplane but might want to compete later with it so I think I will stay with the 61 engine.

Bill D.

Crank:
I believe the FX is a long stroke version while the SF is a shorter stroke. The FX is a torqy engine and will turn a high pitch prop not like the HANNO though.
Can you tell me where I am in disaary?
Or for that matter, can anyone out there tell me.

I think just the opposite. Maybe Terry in LP will let us know. I just switched everything over from Intruder # 1 to # 3, except the servo's. I am sure they are fine, but I like to install new on any new plane. Engine is good, very broke in, SF61. I will test fly the receiver in the trainer/test plane first. I am using the R7000 rx with the X9303 TX. I finally found how to slave GR to E. May need some help in sub-trim, as when I use the trim button, only one E servo in the back moves. It was easy with the 921 RX.


Vince

The SF is a long stroke engine. The piston/liner are the same dimensions as the Hanno Special. The con rods are the same part number. I modded the exhaust ports in a ringed SF liner to approximate the exh. ports on an ABN Hanno II liner and the SF turns (with a tuned pipe on both) at very nearly the same rpm with a 13~9 APC.

Terry in LP

Terry:
Thanks for the clarification. Maybe I will be looko\ing for a good 61 SF to put into another SPA plane.