lfinney

My Feedback: (44)

for those who are interested i disassembled a OS 61 sx-h motor that is new and am replacing sleeve and piston with AAC sleeve and piston from Nelson Engines, the sleeve has a 172 degree exhaust duration. I also disassembled my side exhaust C60f Novarossi engine as well. for those who are interested, this engine was manufactured in 2003 per box info included with engine, I have measured carbs on the OS and Novarossi as well

the carbs measure 10 MM for the OS heli engine and 8.5MM for the novarossi

the crank internal diameter for the the Novarossi is .430 the crank has a knife edge cut on counterweight and turbo relief cut as well as a tungsten heavy metal insert for balance

airraptor

My Feedback: (66)

you can square off the aft corners of that crank where the opening is from the carb.


Also the brass sleeve which engine is that for? if you measure the timing on it you need to average it for the highest and lowest opening for the exhaust port. IE: the peak maybe 185 degrees and the lowest might be 175 for 180 average open for exh.

I have found that on most engines the "turbocut" didnt help the lower rpm engines for most planes. it could be the small gain is offset bt the increase in crankcase volume. I will say the same for the knife edged rod had a small gain 50-75 rpm. that could have been just change in pressure. lol

I do know very good positive with the AAC is less weight and better heat transfer to the case.
When you going to run it?

lfinney

My Feedback: (44)

the brass sleeve is from the Novarossi C60F side exhaust engine and same for the knife edged rod and cut skirt piston. the porting is elaborate compared to my five port rossi 3+2 engines, the turbo cut and knife edge crank is from the Novarossi as well.

I installed the AAC Nelson setup in the OS SX-H engine today and will run Tuesday, and fly Wednesday, I set deck height at .017 which is stock deck height, i have several of these engines NIB, my other one with nelson muffler runs 11x7 well over 14,800 on the bench on powermaster 15 percent fuel, with 158 degree exhaust timing.

speedracerntrixie

My Feedback: (29)

Back when that SXH was new I ran one with the Nelson/Shadel AAC piston and liner. I ran it without any mods except for an additional .010 head shim. I ran one of the Miniature A/C U pipes and header with a 3" headed extension making the header about 8". It was run with Coolpower 30% heli fuel in a X-cell 60. Geat engine, had good manners and was enough to get the heli to 92 MPH in pod and boom configuration.

My current Rossi .45 has the Turbo crank. I'm not sure how much it adds but that engine has always performed well. It spins an APC 9.5X7 pylon prop from 15,800 to 16,200 depending on the conditions.

scoeroo

My Feedback: (9)

I recently finished working over rossi for a guy over in england, 19,000 + rpm on the stand with a apc 8.8x8.75 .............should be a quick little bugger in a slippery air frame

Rudeboy

A Rossi .60?

Better just get a Q500 engine... it will turn that prop a whole lot faster, without any "tuning"... and that's a .40

Tuning engines is fun, but only if you can do it to something that can't be store bought.