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REFLECTOR: More on props

From:           "Al Gietzen" <alventures@email.msn.com>

>From what I've gathered from various pilots of planes using IVO is that they
> get good takeoff and climb performance but maybe not so good cruise.  One
> pilot (Glassair II) described it to me as "hitting a wall".  Improving the
> performance of his engine made no difference to his cruise speeds.  He
> believed that the lack of pitch change on the inner part of the prop made
> that portion essentially a "flat plate" (drag) at high speed.

Was this a an inflight adjustable? The Swings have already found that IVO's
need a different base pitching for fast aircraft like the Velocity and Glassair,
and I'd bet the Glassair had the standard blade, which was developed for
slower aircraft. 
His was in-flight adjustable, but I know nothing further.  There is, of course also the factor that the same prop will perform differently on a tractor than on a pusher.  On a pusher the relative importance of the outer portion of the bade may be greater.

> Looking further seems to confirm that twisting the outer part of the blade
> does give proper pitch distribution.  See also 'More on Prop Design' by Don
> Bates in the January '99 CSA Newsletter, page 17.

I don't get the newsletter, so is this good or bad for IVO's? (As a design idea.)
First of all, there was a word omitted.  It should read that twisting the outer portion of the blade does NOT give proper pitch distribution; which would be a negative for the IVO (according to Don Bates).
Al Gietzen