From: "Houlihan,Tim" <tim.houlihan@oce.co.uk>
Subject: RE: Europa-List: RE: Hand prop a Rotax?
Date: Fri, 27 Aug 2004 19:24:40 +0100
Hi
I thought this would start something.
Its a bit of a Bu**er when practical observation and the laws of physics
disagree.
I know both people involved quite well.
I know people ! its hard sums I have problems with!!
Tim
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Rob Housman
Subject: Europa-List: RE: Hand prop a Rotax?
Something is suspicious here.
According to Rotax the engine must be up to 1200 RPM in order to start, so
let's do some math. 1200 RPM divided by 2.43 (the gearbox ratio) is 494 RPM
at the prop. If we assume a 72 inch diameter prop, then the tip speed is
494 rev/min times 3.1416 times 72 in/rev divided by 12 in/ft equals 9312
ft/minute or 155 ft/sec. Hmmm, that's about 120 knots, and I don't think
any human can move a hand that fast let alone actually turn a prop against
the engine's compression.
So.... either Rotax is wrong or...well, draw your own conclusion.
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airframe complete
Irvine, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]
Subject:
From: "Houlihan,Tim" <tim.houlihan@oce.co.uk>
Subject: RE: Europa-List: Battery position
Date: Fri, 27 Aug 2004 17:40:35 +0100
">Is an external power source point worth having?<
If you don't an engine start with a flat aircraft battery will not be
possible as you cannot hand crank a Rotax."
Over the past three months I have spoken to two pilots who have hand started
their 912 equipped aircraft.
I truly believe both of them.
One of them found that the rising tide was a great incentive !!
He landed on a beach to assist another microlight. When he came to restart
the engine the battery was flat and the waves were only a few metres away.
So he hand started it and saved the day !
He tells me he had done this previously and was surprised when I told it
could not be done !!!
Tim Houlihan
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