Thread: Tachometer setting?

This may have been answered before but I'd like to know why we use engine rpm instead of propeller rpm. Is it interchangeable on the Dynon? I think that propeller rpm would be easier to manage and similar to what most other aircraft use. Also, it'd be less intimidating for people that are afraid of the Rotax "blowing itself apart at that speed". The reason I brought this up is the new article in EAA on the Tecnam p2006T twin that uses RPM of the prop on their display. What do you guys think?

John

John, I read that too, about the P2006T. The thing is that now it would be bassakwards for me to use prop RPM

Hi John,

Most aircraft don't use gear reduction and because rotax basis all their info and performance specs. pretty much on rpms. You will have to convert the rpm with a factor of 2.43:1 to get prop speed.

I noticed most of the TCd Diamond Katanas have prop rpm tachs. From what ive heard the new twin Tecnam is suppose to be type certified to. So far those are the only planes of seen with a prop speed tachs. Rotax may figure its easier to just use crank rpm because they off there engines with multiple gear ratios, 2.27:1 for the 912UL and 914 and 2.43:1 for the S models. It would be easy for Dynon to program the software to translate both ratios but there just must not be a high enough demand for it.