speed-panzer

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Hi all,

what prop size do you recommend for this nice engine? It is planned to be run with a tuned pipe in a 65" wingspan MXS-R, about 10lbs flying weight.
Also your tips for tuned pipe length are welcome.

thanks
Dominik

ronwc

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I would start out with a 15x6 prop and go from there. The 1.08 is a very good dependable engine, high torque, keep tune pipe long and work your way down using a tach. See full info at http://www.macspro.com/tuning.asp

speedracerntrixie

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I have has a couple of these engines. One of OS's best efforts as far as I am concerned. The first was on a Lanier 1/4 scale Laser and the second was on a CG Extra. both very similar to your airplane. The best size was a 15X8. Keep the pipe somewhat long as you don't want a narrow powerband. The 1.08 is a torque monster so so too short will be counterproductive. Both of mine were run on Slimline pitts mufflers.

speed-panzer

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Thanks guys.

I have run my used 1.08 FSR now on for the first time after it got a new sleeve and piston on the bench. So far I am very pleased how it handels. Tuned pipe installed with uncut header, which results in about about 23,5" distance from exhaust to baffle.
I took it of course easy, really rich setting, 22% castor oil, 12x8 3-blade for low load. It looks to become a favourite one!

OldScaleGuy

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I have 6 of these great engines. 16 X 6 is the best prop for this engine.

B-Squared

I bought an OS 1.08 in '94...it's now powering it's fourth warbird. GREAT engine! I run it slightly rich with a 16x8 APC. Currently in a 14 lb Top Flight Sea Fury. Still pulls great!

flycatch

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15X8 ZOAR laminated

JeffH

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That sounds almost like my exact history with 1.08s. 25% Lanier Laser, and then a Byron's .60 sized Sukhoi, both with slimline muffler and APC 15x8 prop. I can honestly say that my 1.08 is the most reliable engine per gallon burned of any engine, gas or glow, that I have ever had. It quit three times on me in probably 500 flights. Once was out of fuel, second was due the clunk flipping forward during the off field landing caused by running out of fuel, and third was a blown plug. If I ever had to change the idle mixture it was because the ring was worn out. I went through 3-4 sets of bearings and 3 rings on that engine. In fact, I still have the engine and would love to find another Lanier 25% Laser kit. I now know how to build it MUCH MUCH lighter.

speedracerntrixie

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I have a soft spot for Lanier airplanes. My last one was a 33% Laser, I has able to lighten it up to 15 lbs and powered it with a DA 50. My 1.08 powered 1/4 scale Laser was just shy of 8 lbs. It was almost like flying a big foamie. I also had a Giles 202. Powered with a 3W 70 twin and came in at 21 lbs.

speed-panzer

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Lots of nice info, thanks to all. it seems I got a OS jewel in my hobby barn....

The MXS-R plane is coming closer to be finished, but progress is somewhat slow. I Installed a tuned pipe half tunnel to the underside of the fuselage, the covering foil still has to be closed again and provisions needed to attach the pipe to. More or less done so far, engine installation is next.

Hope to be able run the 1.08 on the test bench this weekend with the 15x8 and the pipe, and do the stepwise shortening of the header. I will post some rpm numbers once done.
By the way, the carb of mine doe not have the sleeve insert.

airraptor

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I bought one of speedracers Lasers and i got mine to come out at 13.5 pounds dry wih a DLE 55. hover at 3500 rpm lol

Champ-RCU

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In fact, I still have the engine and would love to find another Lanier 25% Laser kit. I now know how to build it MUCH MUCH lighter.[/QUOTE]

JeffH, I have a 1/4 scale Laser kit by Lanier I'd let go, make me an offer.

Mark


P.S. I think only the OS 140 would be my vote to beat the 1.08. (But not by much.)

speed-panzer

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Finally some figures, still from test bench:

9.700rpm @ 22" pipe length, 8% nitro, 15x8 Master Airscrew.

Engine is now installed to airplane, and I am going to cut one more inch off the pipe. Hope to get into the 10K range then.
That will be plenty for this little airplane, I am sure it will be less 10lbs flying weigth.

Thanks all for your input.

Dominik

speedracerntrixie

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Speed, ditch the Master Airscrew paint stick. If you tune the pipe with it and then put on an APC your pipe timing will be too short. Although the MA prop is a 15x8 under rpm the blades flatten out and you end up with a 15x7. APC props hold their shape.

speed-panzer

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Yes I heard it more than once to better call those MA props a paint stirrer...
And in fact most of the time I am using APC or Graupner G-Sonic props. That 15x8 MA was just at hand.... need to buy an APC.

stuntflyr

Use your Prather Pitch Gauge and notice the Master Airscrew is one inch less than advertised anyway.
Almost all props are short about an inch of pitch than advertised, except APC. They are a quality unit, especially for the money.
My dad has a 1.08 in his 17 lbs Four Star 120, that thing is amazing. Best engine ever. I'm finishing a Lanier Laser 1/4 scale and have a 1.08 in it. Can't wait.
Chris...