Percentage of Nitro used in a Norvel, R/C BB engine

Hi Ken
It is a Norvel .15 with Ball bearings never been started.
Nitro % best you think?

Thanks
Darren

About 10% nitro is fine, what is more important is the oil content and type. The cylinders are very rough when new, so for me it is all castor oil and 20-25% of it.

The stock engine throttles excellently (idles reliably at around 2200rpm) but the carb is a little restrictive on the high-end. So if you are after more power you can simply switch to a different carb, the MVVS .15 carb is a direct swap-in for instance. I wrote some of my findings on RCU quite some time ago, try a search there and you'll find lots of useful info.

Here is one of the threads on RCU, for instance: https://www.rcuniverse.com/forum/1-2-1-8-airplanes-70/9450797-norvel-15-big-mig-again-2.html

Here are my tach numbers from that time:

"Here are some numbers with the muffler on:

Stock carb, APC 8x4 prop, 10% nitro: 14400rpm
MVVS carb, APC 8x4 prop, 10% nitro: 15800rpm

With the MVVS carb the performance pretty hard to match by any other .15 engine, especially if you consider the low overall weight of the engine."

Do you have the spanner wrench for the head insert ? The design of this has changed somewhat over the years and the latest had a mill finish head clamp with peripheral holes around it. When new, due to heat cycling the clamp will loosen offering little to no compression. I actually put some Ultra Copper RTV around the threads and retightened and never looked back. This engine has a good deal of pinch when new and takes a bit of fussing with using a heat gun to pre heat the cylinder as it will lock up at top dead center.

Yes, as with all Norvel revlite technology cylinders, lots of castor and preheat is the way to go. Once run-in they are very reliable and easy starting.