Correction:, I meant to say 72" prop. I makes a great difference!
Pops
-----Original Message-----
From: owner-europa@post.aviators.net
Subject: RE: Flying: Performance: Speed kit.
Another question from the uninitiated:
I wonder, are the "crankshaft oscillation" and resonant RPM's less critical
on a geared engine like the rotax vs. a direct-drive Jabiru? Are they
significant at all? I would imagine that the gear-train filters much of it
out? Or does the gear backlash etc. set the system up for some worse
resonance's? I assume the former from Tony's subsequent reply?
Cheers & and Holiday Wishes,
Pete
-----Original Message-----
Subject: Re: Flying: Performance: Speed kit.
Hi! Mike.
MT Propellers ,in my case supplied the propeller
kit fully balanced, however they insisted that to
maintain warranty conditions it must be supplied
back to them within 50 hours for strain gauge and
dynamic balance tests with the particular engine
combination to identify any resonant RPM's over
the full range of operation.
This now completed a "non-flying" peak resonant
range between 2150 rpm and 2400 rpm has shown to
be present, and they are recommending not to
cruise in that range if possible.
I guess if I can't live with that it means
another trip back to the factory for flight
testing to try to narrow the non- useable range.
The point about this is that simple balance isn't
the full story and further strain gauge testing
needs to be carried out to do the job in a
professional manner. Only with that test can it
be established what crankshaft oscillation is
taking place, allowing you to select the most
engine /propeller friendly flying.
Best regards
Bob Harrison
G-PTAG Europa MKI /Jabiru 3300
Quoting DuaneFamly@aol.com:
> Please excuse a dumb question.
>
> How do you know you have an out of balance
powerplant setup? If it is
> "really" out and you start the engine, can you
do damage before being
> able to
> shut it down?
>
> Mike Duane, San Jose (soon to be Redding)
California
> Lurking for a long time but hope to build soon.
>
____________________
> The Europa List is supported by Aviators
Network UK - info@avnet.co.uk
>
-------------------------------------------------
This mail sent through UK Online webmail
|