proemer wrote:I typically use 4800 rpm on the analog gauge, which shows up as 5150 on the Dynon... (take your pick!) for "high speed cruise".
This is no small difference. If my analog tach is reading similarly low, if i’m selecting 5,200 rpm for cruise, it may place me at or above the 5,500 rpm limit for continuous power. I actually re-pitched my prop due to low rpm indicated (less than 5,000 rpm) on takeoff and climb - I now see 5,200 rpm for better performance there, but I think it hurt my cruise performance. My cruise speed and range for any given rpm went down and my fuel consumption increased. If my analog tach is in fact reading low, that explains a lot and re-pitching back to factory specs would be worthwhile.
Leading to these questions:
1) Pete, do you have a Dynon D10A? Did it come set up to show rpm or did you have to modify it? I’ll check my D10A manual to see what’s involved. It may even show rpm somewhere that I just wasn’t aware of.
2) Is the signal going to the analog tach a digital signal? I assume it is.
3) How hard/expensive would it be to replace my analog tach with a digital one? I previously did so in my Tiger and found the improvement in accuracy and readability worthwhile.
4) I know there will be math involved due to the gearbox reduction ratio, but is there an inexpensive device to check propellor rpm? Does anybody have one? I’ll check with our on-field mechanic later today.
Thanks! Bear in mind, my Sky Arrow is EXPERIMENTAL, so anything goes!