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Cruise speed increase

PostPosted: Thu Oct 26, 2017 9:31 pm
by Johnny C!
This won't be a surprise to most of you,
but when Scott & I set the pitch on my
Ivo 2 blade Patriot prop on Lima Charlie,
after the first few flights that "felt right"
I had kind of forgotten about tweaking
the pitch until today. I added a half turn
of positive pitch and went from 93 mph
at 5300 rpm to 103-105 mph at the same
rpm. I couldn't believe it so I set up to
check it several times and kept getting
about the same each time. It was a little
choppy to today, but it really seems to be
true. I am going to leave it for a while to
verify a few more times, and later I'll
dial in more to see how that goes.

With the new setting I am still using well
less than half our runway, so I feel I have
more room to play. If I can break 110, I
will be a very happy camper.

Lima Charlie is a Trilander with an 80
horse Rotax. This has got my juices
flowing to get my wheel pants finished.

Look out Dennis C. I'm coming for you!

John

Re: Cruise speed increase

PostPosted: Sun Oct 29, 2017 10:37 am
by scubarider2
Keep trying John...and let me know any exciting tweeks you make. I am at 105mph pushing 5400rpms. I generally "cruise" at 5200 at about 95-100mph. :mrgreen: :mrgreen: :mrgreen:

Re: Cruise speed increase

PostPosted: Sun Oct 29, 2017 8:25 pm
by av8rps
John,

I'm curious what length 2 blade IVO patriot prop you are running? Sounds like you are getting good cruise. I'm happy to hear that as so many believe these planes are 85 mph planes, but they're not. Mine will do 110 at 5500, but I have the 100 hp 912. So for 80 hp you are doing good!

Paul

Re: Cruise speed increase

PostPosted: Wed Nov 01, 2017 9:27 pm
by Johnny C!
Paul,
It a 72" dia 2 blade.

I think I will tally speeds at say
5000, 5100, 5200, rpms etc every
time I fly. I think that will help
clarify exactly what I'm getting
at the different revs, over several
flights.

John

Re: Cruise speed increase

PostPosted: Thu Nov 02, 2017 12:05 am
by av8rps
It's interesting to see your good speeds with a 72 inch 2 blade. Especially with the 80 hp 912, I would have expected it to be a 68 or 70 inch. I've played around a lot on my 912ul Kitfox amphib with a variety of 3 blade IVO prop lengths to learn what is old news, the fastest cruise prop is a 66 or 68 inch diameter, but a 72 inch gives a better climb and better off the water performance.

My Highlander with a 912uls has a 2 blade 70 inch ground adjust Sensenich that works very well for climb but yet will get me that magic 110 mph.

Finding what is the best prop on a plane reminds me of finding the holy grail :wink: