jfrost

What is ideal static RPM using 23/8 prop? It hovers well at half stick,
but very sluggish between half and full. Thanks for any suggestions.
(Edge 540 - 84", 8 kg wet, using 3W/Wood 23/8, pit style muffler).

krayzc-RCU

My Feedback: (31)

has the high end been set with a tach?

ram3500-RCU

My Feedback: (221)

Mine showed this symptum till I finally got it leaned out all the way, both on the low and high needles. I now have lightning quick transition.

Ih82crash

If I understand your question. you say that your engine runs well, but your throttle does not have a linear response. That is a very common thing with gas engines. the best way to fix it is to program a throttle curve in your radio, then you can set it up so you have more pull between half and full throttle. Personally I don't worry about it, since most of the flying is between low and half throttle. the only time I really need full throttle is to pull out of a hover.

jfrost

Hi, thanks for your reply re 3W55I engine, after checking RPM with tach at half stick 5600 and
full stick 6000. This was the most consistent RPM after I tried to lean main needle I got 6300 at
full stick but soon after it started to sag and RPM reduced to below 6000 and engine was running
too hot (around 100 degrees Celcius). This was static test on the ground. Any ideas?
Thanks - Joe, Australia.

jfrost

Thanks for your reply, I have tried leaning the main needle - I managed to get 6300 maximum RPM using
23/8 wooden prop, but it was too lean because soon after it sagged and RPM fell below 6000 and engine was
starting to heat up (this was static test on the ground). After this I went to my original setting.
I am going to try carbon fibre prop, do you have any suggestions?
Thanks for any ideas - Joe, Australia.

krayzc-RCU

My Feedback: (31)

put a mix on that baby

ram3500-RCU

My Feedback: (221)

This engine utilizes reed valves. This normally gives it very snappy responce in the middle but can cost a few RPMs on top if they 'float', if it is under-propped. I still think, if the low and high neadles are right (they work together untill you reach almost maximum RPM), your midrange responces should be excellant. I use 87 octain with Mobil 1 in a 50-1 mix, and get great transition. My engine also pulls the plane vertical at about 50MPH and that is rolling. I can also snap on the way up and keep going (not at 50 MPH). This is with 16.5 to 17lbs of plane. My engine is broke in now and doing all I ask of it. I'm sure yours will also. These are powerful engines IMO.

Don't worry so much about top end RPM right now. Adjust your neadles so that you can gun your throttle (after a brief idle) with absolutly no hesitation or sag. As it breaks in, minor tuning will be needed, but you should still have this good responce during the break-in after the first couple gal when it is still very rich. I did. This is what reed valves in the 3W do for you.