Spaceclam

i own an os .91 pumped four stroke, and i am looking to get the last drop of power out of it i can. here are my guidelines:
*Will not go above 20% nitro
*will not get bigger engine
*will not spend more than $50 per improvement

what are your guys' suggestions?

Flypaper 2

No muffler, straight pipe. bigger carb, maybe Perry.

jettstarblue

....that would do it...don't expect any idle though....
Really, I'd say w/20% your gonna get about all your gonna get from that thing.

Jetts

CafeenMan

Also depends on what kind of power you're looking for (climb vs. speed). Have you tried a variety of props? Usually you'll see a marked improvement in whatever it is you're looking for by simply changing to a different prop.

Spaceclam

climb. i am running a 14x6 prop and i am reluctant to lower the pitch further because my plane stals at around half throttle already, even though it is way overpowered. why would i not expect any idle? it is a pumped four stroke, and i have found 0 flow restriction mufflers, but once again, why no idle?

Flypaper 2

Jetts is correct inasmuch as A larger throat has less vacuum so a little less efficient, but the Perry carb is one of the most efficient so I think it would make up for it. Worst case is it would idle a little faster, although from the high stall speed means you land it with some throttle on anyway I imagine.

MinnFlyer

My Feedback: (4)

Try a graupner prop. They are fabulous on 4 strokes

Spaceclam

i will try a graupner prop. here is the thing though, i can't replace the carb. i have a pumped engine and the regulator is attatched to the carb. it is specifically designed to fit modified os carbs. also about the high stall speed thing, yes, i do land it with some throttle, but i have to bring the idle dangerously low on the ground to keep it from scooting off.there is a delicate balance there. wait until you are over the runway to cut throttle, and bring it down really low and do circles. i can't use a break because i have a tail dragger

CafeenMan

Go to more diameter and less pitch. You'll get a lower idle with less thrust and a better climb, but a lower top-end speed.

Spaceclam

I'll give it a shot

DBCherry

My Feedback: (4)

I'm not sure you can go much higher diameter to pitch than the 14 X 6. Maybe 15 X 5.

You haven't told what the plane is, weight, etc. My guess is, the best way to increase your climb performance will be to reduce weight. Lighter tires and landing gear, lighter battery pack, servos?

Knocking 10 or 12 ounces off the weight could dramatically increase your performance depending on the plane.
Dennis-

Spaceclam

it is a .60 sized cap 232. i am planning on using the dave brown light low bounce wheels, ad ..75 oz a pop as opposed to 2 oz for my current du-bro tires. however, being a tail dragger, it will only save me about 2 oz. there is not really much else i can do for the weight, besides stripping the covering off, and drilling out the components, weakening it and making it less stable under the constant winds at our field. that is why i am trying for more power. i just recieved a 9 oz bottle of that nitroblast stuff, i am going to knock it up to 20% because the heat nitroblast shaves off, i am going to run an apc prop, and last but not least, go with a 0-flow restriction muffler. my engine is pumped, so i can take it off if i want to. i just hope thatis enough

BigSTIK40flier

i would try a 15 x 3-5 pitch. IM NOT RESPONSIBLE IF YOUR PLANE STALLS AND CRASHES

Spaceclam

i won't go lower than x5, but responsible or not, if it stalls and crashes, i will still yell at you, just because i will be really angry, not because you did naything wrong

BigSTIK40flier

lol, beware i yell back :P




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