Well – it’s not just the ‘flat’ section; it’s a matter of pitch distribution. The twisting of the blade happens mostly out toward the tip, and changes very little toward the root.  True; most of the thrust is generated further out, but not changing the pitch on the inner part of the blade affects top end ability.

 

Another 2 cents worth..

 

Al G

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Bradburry
Sent: Thursday, March 12, 2009 2:50 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: IVO Prop

 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Thursday, March 12, 2009 1:09 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] IVO Prop

-------------- Original message from "Mike Wills" <rv-4mike@cox.net>: --------------


> John,
>
> I looked pretty seriously at the IVO a number of years ago. But was scared
> off by a number of things:
>
> 1) Watched Dave Atkins repairing a delaminated trailing edge on the flight
> line at Copperstate fly-in.
> 2) A friend with a Kolb Firestar/Rotax 503/ground adjustable IVO had the
> prop come apart in flight resulting in a forced landing that totaled the
> plane.
> 3) Tracy's experience re reduced performance at speed.
> 4) The issues experienced by Lyc powered users.
>
> Numbers 1 & 2 were possibly due to something going through the prop with the
> engine running. Issue 4 seems to be not relevant. This leaves Tracy's
> experience with the IVO. I wasnt thinking about the fact that you fly a
> pusher when I asked, but presumably a pusher would not have the prop root
> issue that Tracy reported. On my RV-4 I use a much larger than stock spinner
> and this issue may not be as significant as it was for Tracy. But I'm not
> sure I want to buy one to find out. My current prop seems to be pretty close
> though I havent flown it enough to really make a judgement.
>
> Thanks for the feedback.
>
> Mike Wills
> RV-4 N144MW
>
>
>
> ----- Original Message -----
> From: "John Slade"
> To: "Rotary motors in aircraft"
> Sent: Tuesday, March 10, 2009 9:41 PM
> Subject: [FlyRotary] IVO Prop
>
>
> > >I didn't know anyone had ever had any success with an IVO. Tell me more.
> > What do you want to know? Its a very well engineered piece of equipment.
> > The CF blades are hollow and have a steel rod running to the hub.
> > Activating the motor via brushes twists the steel and thus twists the
> > blades equally. The twist change is quite visible. There were problems
> > with the individual blades slipping on the hub. This has been solved by
> > providing a knurled hub, and not selling to guys with Lycomings. The IVO
> > is available for rotary, subaru, Franklin 6 and other less "pulsy"
> > engines. After the first 15 hours or so my blades have hardly taken any
> > extra torque.
> >
> > My performance is greatly enhanced compared to the fixed pitch Performance
> > prop. Static with the wood prop was around 4500. With the IVO on full fine
> > I get closer to 5400 which gives me access to a lot more power on take
> > off. I've never done a "high speed" run with the IVO, but I've had 180 kts
> > indicated at 2000' a few times without much effort, and without ever going
> > to the full course setting. Another nice bonus is that throttled back on
> > full fine for landing, the prop acts like a brake. Its much easier to land
> > and stop than the fixed pitch that's pushing you along fairly well, even
> > at idle.
> >
> > I know a Velocity driver (Mike Watson) who also uses an IVO (Franklin 6)
> > and is very happy with it after around 5 years of use.
> >
> > The factory people are very easy to deal with and very helpful.
> >
> > The Cozy Girrrls are installing an IVO. What better recommendation could
> > you want? :)
> >
> > Regards,
> > John Slade
> > Turbo Rotary Cozy IV, N96PM
> > 98.1 Hrs.
> >
> > Mike Wills wrote:
> >>
> >>
> >> Mike Wills
> >> RV-4 N144MW
> >>
> >> ----- Original Message ----- From: "John Slade"
> >> To: "Rotary motors in aircraft"
> >> Sent: Tuesday, March 10, 2009 10:30 AM
> >> Subject: [FlyRotary] Re: Ground Testing
> >>
> >>
> >>> The IVO electric in-flight adjustable costs around $2350. I'm very
> >>> pleased with mine. My "spare" is a $2700 fixed pitch wood prop thats a
> >>> piece of art, but doesn't work anywhere near as well.
> >>> John
> >>>
> >>> Tracy Crook wrote:
> >>> A variable pitch prop would be nice to get the best of both worlds but
> >>> it's an expensive option and $10,000 buys a lot of gas.
> >>>
> >>>
> >>>
> >>> --
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> >>> http://mail.lancaironline.net:81/lists/flyrotary/List.html
> >>>
> >>
> >>
> >>
> >> --
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> >> http://mail.lancaironline.net:81/lists/flyrotary/List.html
> >>
> >
> >
> > --
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> >
>
>
>
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