.45 - .51 engine recommendations

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I don't have a K&B .61in front of me, but I doubt that it weighs as much as the hefty 18 1/2 oz of the ST.51. Wouldn't be concerend about being too much motor in the power department either - it's an ancient design. Good in its day, but not a match for engines of lesser displacement but advantaged by laminar flow porting.

Abel

OS .70, Saito .72, or just about any other 4 stroke in that size range would be very suitable for that plane. I flew one with the OS and it was sweet. Just enough power for scale-like aerobatics on low nitro.

If you are into 2 strokes, it would be hard to beat the Thunder Tiger .46 Pro.

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The .61 would be better still, however the ST .51 would certainly be an excellent choice. The Citrabria is, IIRC, over 65" w/s and some 750 sq. ins. w/a. If the KB .61 is a relaible item, then it would be my first choice. For scale/scale-like flying I much prefer cubic inches and steady running to max. rpm outputs.

Enjoy whatever you decide.

Webra Speed .50. Dr.1 Driver "There's a Hun in the sun!"

Thanks for the advice, everyone, keep the suggestions coming.

If the MECOA website is to be believed, the K&B .61 weighs 14.25 oz, but I don't know whether that figure is with or without muffler. II supposee I could weigh it.

'm not even going to bother quoting power outputs, as those numbers tend to be complete fiction.

I wouldn't be surprised if the ST .51 makes more max power than the K&B

61, but whether or not it makes more total horsepower within the usable RPM curve is another matter.

FWIW: I am more than willing to sacrifice speed for climb and throttle response.

I am pretty sure that weight includes the muffler. You would likely use a pitts muffler on a J-3. The Supertigre mufflers are very good but also very heavy. The K&B is light for a .61 is this the new screw head or the older loop ported version?

I don't think that includes the muffler. If it did, that would make it lighter than any BB sport 40-46 engine. It is light for a .61 but not that light.

my crossflow .61 with K&B muffler and metal K&B carb is 18 1/4 oz, but thats with years of castor gum on the outside, and the Perry or Irvine carbed models would be slightly lighter.

Less power than my TT40 pro, but is easier on fuel, hand starts great and swings a bigger prop. Sig 1/5 Cub flew like a real Cub with it.

** mike **

This is the loop ported version. Old skool

-- Prawni

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likely

I was talking about a .61 engine. Average .61 engines run 20 oz and a lot more. Look at the weight of a Rossi or GMS .61.

My old K&B/ Veco 61 is about 14.5 oz's no muffler. My 46 pro has more go, but

14k rpm cubs just don't sound right. Put a long flat prop on the 61 and a quiet muffler, shud have enough pull.

Bill