Arf Flight streak.

[Randy.Birt]

Greetings all, quick question.  Putting an OS fp 25 on my Arf flight streak. Am I correct that a 9x4 is the appropriate prop. If not, what else would you recommend? Thanks y'all

[Randy.Birt]

Thanks Ty, we already found that out, the 16 year old son lawn darted it and I am having to do repairs. I never really like the fox 25 that was on it, so as i am having to take everything off the nose to fix it, I figured i would put on a better motor. I have two FP 25 and two fp 20. I figure one of them will work well for this plane.

[Brett Buck]

Thanks Ty, we already found that out, the 16 year old son lawn darted it and I am having to do repairs. I never really like the fox 25 that was on it, so as i am having to take everything off the nose to fix it, I figured i would put on a better motor. I have two FP 25 and two fp 20. I figure one of them will work well for this plane.

   I would suggest a 20FP and an APC 9-4. Everything else on the engine should be *stock*, repeat, *stock* out of the box, exactly as it came, with all the parts including the muffler.

    Brett

[Randy.Birt]

Thanks Brett, I will do that. I appreciate the input.

V/R

Randy Birt

[Perry Rose]

I put a 1/2 inch thick cheek piece on the non engine side for strength.

[Leester]

where's the engine ?  on the inboard side ??

[Brett Buck]

APC 9-4 is a good prop. The 9-4 master airscrew will be a little less pitch and less load if you want to slow it down a bit.

   The APC is *much less* load in the air than the Master Airscrew, that's why it works. The key to the entire system is to get it revved up enough to run smoothly.

    Brett

[Randy.Birt]

Brett, while we are on the topic, any recommendation for fuel tank set up for this engine? Muffler pressure or no?

Thanks

Randy

[Brett Buck]

Brett, while we are on the topic, any recommendation for fuel tank set up for this engine? Muffler pressure or no?

Thanks

Randy

  No topic has ever been covered better than how to set up a 20FP, to the point that everyone has long since gotten sick of it, but quickly:


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   BOX-STOCK OS 20FP ABC with STOCK E2030 Muffler and NO, repeat NO modifications of any type. Break in per directions
   OS Glow Plug (as supplied)
   APC 9-4 prop
   VP/Powermaster 10% fuel (any 10% RC-type fuel will do, 15% will also work)
   Stock Sullivan SS-4 clunk tank set up per instructions for a 3-tube system (hard uniflow into "bump", overflow into inner/upper/right corner, clunk pickup), flat side of tank set up against fuselage and centered on engine, uniflow vent plugged and overflow open to get suction tank. Muffler pressure into overflow. You will need about 2.0 ounces of fuel on a broken-in engine, WAY more when it's still tight.
*********************************************************************************************************

  Your tank should be no wider than 1.5" from the bottom of the engine lugs to the pickup, less is better.

   I will elaborate later when I get home.

    Brett

[James Holford]

A thunder tiger pro .25 with a 8x5 makes it a hoot to fly

Sent from my SM-G965U using Tapatalk

[Gary Dowler]

   I would suggest a 20FP and an APC 9-4. Everything else on the engine should be *stock*, repeat, *stock* out of the box, exactly as it came, with all the parts including the muffler.

    Brett

Agreed!  Ive been following this very advice for some time now, and it works!  The FP's thrive on RPM. Don't try to 4 cycle them, or you will loose all of the advantages they bring.  Lean it out, then just open the needle until you hear a slight RPM drop (on my 20FP's this is around 12,300) and go. This set up replaced the Fox 35 on a couple of my planes and improved things noticeably.  Now if I could just get the idiot behind the handle to catch up with the airplane.......LOL

Gary

[Steve Dwyer]

It took me a little coaxing from friends to try an OS LA 25 with a 9x4 prop on my latest build Flite Streak instead of one of the tried and true Fox 35's I have been using on several OTS models.
The 25 or 20 with a 9x4 is a great combination, for a perfectly consistent strong run. And yes we can fly without the coveted Fox 4-2-4 break.
Steve

[Randy.Birt]

Brett, I found and printed out the 2006 Posting from Dan Rutherford. It is a several page discussion, and answers just about all my questions. Thanks for the heads up.

V/R

Randy Birt