Hircflyer

Hi,

Need some clarification please........on the spec sheet max rpm for this engine is 6000 rpm, other places indicate max rpm is 5500 rpm.

I broke mine as per instruction sheet with engine, almost a gallon of fuel with a 18x12 prop. Oil coming from vent is clear. Engine runs very well and has good idle. Because of uncertain accurcy of tachs used several from friends and the engine at not quite fully open on the carb barrel is reading 5300 +- 100 rpm, I am not sure what reading would be if carb was to go full open.

Sorry long time to reach point ......am I under propping engine? or is this normal and should I fix throw on servo to stop at this point? I can richen to achieve lower rpm but it then is really rich and smokes a lot.

Any further prop recommendations? Your information only lists the 18x12.

Thanks for your help.

PS engine really runs great and is going in a GP Stuka. Starts on second or third flip every time. [8D]

RCV Engines

Hi
For general running I would recommend aiming for around 5000 - 5500 rpm. You would not harm the engine though it you ran it at 6000rpm, but this is at the limit.
On an 18x12 prop the average maximum rpms is 5500, so I would be confident that you could run your engine with this prop at full throttle.
If you are looking for some other alternative prop sizes, please see the list below (I have also included average maximum rpm figures for your information)

16x16 2Blade - 5250 rpm
17x13 2Blade - 5500 rpm

15.75x13 3Blade - 5300 rpm

14.5x11 4Blade - 5400 rpm

I hope this help, but if you have any more queries, don' t hesitate to contact me.
Best regards
Laurenne

Hircflyer

Thanks for the information.......do you recommend wooden props or are the APC's okay?

RCV Engines

All of our testings and prop rpm ratings are done of APC propellers.
The main problem with wooden propellers is that they do vary in quality. Zinger propellers are generally of high quality.
The other thing to remember is that wooden props are less efficient than glass composite ones, so they will reduce rpm.

I hope this helps
Best regards
Laurenne

Hircflyer

Thank you for all your information. Reason I was asking I had heard that the APC props were not good to use on the RCV engines because at the lower RPMs of these engines produce, the APC props were not efficient..

If they are good enough for you I'll use them.[8D]