JS615

Whats the best setup here,,, F20 tiger shark, ys 45 with tuned pipe,,, what would be the best overall prop, and where should i start as far as the header length??????? What should i expect for rpm, best! without destroy the engine to quick!

HighPlains

My Feedback: (1)

I've got one of the RE 45 engines NIB. I've seen one in a Prather Toni running pylon quickie props, and I think the RPM was in the 16K+ range. The note that I threw into the box with the engine was a header length of 5 1/2" measured from the plug with a Mac's pipe.

freakingfast

My Feedback: (3)

YS 45 FR, FS tune length with a Macs MARINE muffled pipe (#1349) tuned length 11 5/8" measured from glow plug to large diameter apex on pipe. Note, start about ½� longer than this and tune your own system, engine port timing and pipes are not all the same.
This measurement is the "stretched/strait" length or true distance from glow plug to apex (the high point on the pipe). It will appear shorter if you have a riser, doglegged header or side exhaust. I use a mini tubing cutter and debur the I.D., make sure the chips don't get in the engine. A good engine, broken-in & good bearings should see a minimum of 16,300 on 15% nitro with an APC 9X9 and a good tuned pipe, this is my benchmark. On 30% expect about 800 more. With a Marine (nitro) pipe I have seen 17400+. These are peaked numbers back off a bit rich for flight. If it lugs/sags in the air and there’s no smoke land and richen. In all cases it should unload a bunch in the air. This engine is finicky about glow plugs and realy likes OS #8s. If you use the full length header it will pull a good size prop at lower RPM's but it will be sad for speed.

a 9X9 prop is for a very clean plane like a Diamond Dust, Demon, Whiplash or a Quckie. A 10X6 has the same engine load and gives about 1 pound more thrust at the expence of a lot of speed. Try them both on the F-20.

http://www.macspro.com/tuning.asp
http://www.macspro.com/pressure.asp

freakingfast

My Feedback: (3)

Dont forget to run-in the engine with a 9X8 APC at a rich two stroke sound, wide open throttle. 15%nitro 18%syn&caster or more oil for run-in. It's best done on an engine stand.
Tune the pipe further AFTER run-in, three or four tanks.

SpeedBoy

I have been running YS 45 for 5 years , on airplanes like ultra sport and patriot , my better results with this kind of airplane have been with 10x7 and 10x8 APC ( 10x8 strictly shaved and 20% nitro ) with tuned pipe 7.5 c.c. , I can't remember if the length of the header is 5" or 5 1/2 " , RPM around 15,500 and plug O.S. R5 . But this is just my case .

JS615

Thanks for the info guys, this will really help.. I got this engine from a friend, and its new in the box,, i know it has not been made in a while, but i was told that parts are still avalible... thanks again.

Grodus

I have a YS 45 RE with a Mac header and a Prather marine pipe turning a 9x9 APC. From the plug to the apex of the pipe is 12 3/4". Sorry I dont remember the rpm's and my tach is not working now but it is scary sounding. My is currently yanking around a Direct connection Dodger. I had the motor on a DC F-20 years ago. Experiment with a 9x9, 10x8. I think I liked the 10x8 better on that airframe.

Cody

still4given

I'm running one on a BH Spitfire 40 with an Ultrathrust muffler. So far I like the APC 10x7. Turning about 16,400 on the ground. Great little engine.

Blessings

freakingfast

My Feedback: (3)

There you have it, 9X9, 10X6, 10X7 and 10X8 (shaved?). Start plenty long on the header with the 10X7 & 10X8 and work down. Fuel, plug, prop, pipe & plane all work best if the header is tuned for each package.

still4given, 10X7 @ 16,400 W/Ultrathust, that's pushing 2 hp....as good as any pipe will do, Im impressed!

Cyclic Hardover

My Feedback: (3)

I'm running a 9/7apc on my F-20 with a Jett 50. IMHO the YS 45 with a tuned muffler or pipe is equal.