|
|
Hi Tommy,
Congratulations on the "caged animal". Regarding the prop, no nothing
about the Ivo, however, you need to tune it for max thrust! Now there is a
bit of helpful information. You do have a thrust meter , don't you? {:>)
Not having a thrust meter, you need to balance power making with thrust
making requirements (at least enough to get you safely off the ground). One
thing you definitely do not want to do initially is tune the prop it for max
rpm - while that may produce gobs of power, you will have your pitch set too
low to produce a safe amount of thrust.
First if you are only getting 25" MAP and you are near sea level, then
you have airflow interference problems. I would not like less than 28" MAP
at WOT. So either you throttle is not opening all the way or you have one
hell of a filter or you are at 5000 feet elevation. Think about it, if you
stop your engine with the throttle open the MAP will read 29.92" (if at sea
level and standard day). So even if you run your engine out of power (prop
load too heavy), you should still be able to get within 1" or so of 29.92".
Now you stated that you thought you had some throttle left. I would suggest
that go out fire that animal up again and advance the throttle 'till it
won't advance any further and then check your MAP. If not close to 29.92
then start checking your intake.
I am going to send an e mail to a friend of mine who has a rotary in a
Glastar with an IVO prop and see if he can tell us what his is set at for
take off. Will get back to you with what I find.
Best Regards
Ed Anderson
----- Original Message -----
From: "Tommy James" <twjames@healed.org>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, June 19, 2003 2:19 PM
Subject: [FlyRotary] Ivo Magnum Pitch Question
> Okay, here is a real test of this groups aeronautical acumen.
>
> On the front of my Glastar is a ground adjustable Ivo Magnum (3 blade).
The
> "destructions" advise that it is adjustable from 30" to 90" pitch by
turning
> a large adjustment screw which twists a cam in each blade. This screw has
5
> turns stop to stop, or 12" per full turn of the screw. The prop is
> currently set at ~54" of pitch. I ran the engine this morning to ~4500rpm
> and 25" MAP. While there was throttle left, the engine did not seem to
want
> to advance from there.
> The plane was bouncing around like a caged animal... This is new ( and
> exciting) to someone used to C152s.
>
> The test:
> How would one determine the correct pitch for first flight and what is the
> guesstimate of what that pitch should be?
>
> Regards,
> Tommy James<><
> ps. no further starter problem
>
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
|
|