Max RPM question from the Newbie

On 10/1/2003 3:49 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

What are your RPMs with the 13x6 ? What brand and nitro/oil fuel ? Are you using a tach or doing it by "ear" (You can not accurately tune a 4 stroke by ear) ?

You should have no problems with the prop. Have you checked to make sure your needle valve hasn't picked a piece of lint/crap ? Have you tried a different fuel and/or glo plug (OS F works exceptionally well)? If you are at higher elevations you will need to run higher nitro (20% or better) to get the performance.

You can tune a four stroke by ear. Thousands of people do it every day.

What RPM are you trying to achieve? You are not going to get over 10K with a 13X6 on that engine. A Saito 65 is about equal in power to a strong 46 two stroke.

What fuel are you using? What is the oil type and content?

Here are my recommendations:

I have used an APC 13x6 on my Saito 65 for years. It turns about 9,300 rpms. My next favorite prop for the Saito 65 is a APC 12x7.

If the airframe is heavy or has a lot of drag then a 13x6 is a burden on the engine. But for a .40 size or lite weight .60 size plane a 13x6 is fine, if it gives you the performance that you're happy with.