Climb Prop Basics

[fangzz]

Just this week had my prop re-pitched to climb specs. o-300a/7651. I'm headed west from the southeastern flatlands. Did this last year, about now, and was underwhelmed by my 7655's performance. Actually, for that prop, we did quite well, but it was far too exciting for my taste. So, I thot I'd ask you more experienced sticks for some of your lessons-learned, if you have any you'd like to share. Such as...

Did you find that the higher rpm's had a tendency to cause cht concerns?

How high were you able to climb at max gross?

Anything I should think about re rpm management, realizing the rpm will rise into the yellow, or even red, quicker, easier( other than - don't let it)?

Is 2450 still our best normal cruise rpm?

Anything else you folks can think of? Thanks a bunch ahead of time. Drew

[fangzz]

Thank you, Aryana. Exactly the type input I was looking for. I keep hearing that about this/these engines - they work best when run hard. I like that. What's your ceiling at gross with your climb prop?

[buzzlatka]

I went from a 7653 to a 7651. Lost 4 knots or so in cruise. Highest altitude I have seen is just over 12k. That is light and I quit trying to go higher because I had terrain cleared.

[fangzz]

Did you guys have any cht issues in max climb mode? The altitudes you reached sound 'useful'.

[GAHorn]

CHT issues are for the most part unrelated to prop pitch. They are most affected (other things being equal) by fwd-speed and cowl/baffel conditions.

[KS170A]

Had my standard-pitch prop up to 13,800 to get as much margin above cumulogranite while crossing the rockies with a 30-knot tailwind and virga above. Some downdrafts were obvious and could be avoided, others not so much, hence wanting as much altitude as possible. CHT never was an issue. Oil temp is usually the issue.