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Tracy,
My RV static RPM is 5350 - 5400 with my
Warnke prop which seems pretty good. This is with a 2.17 ratio
RD-1. When the prop unloads in level flight what should I expect to see for
RPM at full power? Max RPM I've seen in level flight, full throttle, 8,000' was
about 5700 - 5800 but I may not have given things enough time to settle
out. What are people typically setting for cruise RPMs/MP? With the limited
flight testing I've done so far my engine feels pretty comfortable at around
5,000 RPM and that has been a typical power setting for me to date. Still
getting used to the different sounds and sight picture with the high RPMs and
cheekless cowl.
At higher power settings/RPM it feels "busy"
- hard to describe and it may just be a comfort factor thing that I need to get
used to.
Mike Wills
RV-4 N144MW
----- Original Message -----
Sent: Wednesday, March 11, 2009 8:48
AM
Subject: [FlyRotary] Re: IVO Prop
Yep, should have thought about pushers when I wrote that
comment. The IVO seems to work well on pushers since the stalled inner
part of the blades is in turbulent air and doesn't cost them the drag that it
does on tractors. Tractors are pretty much stuck with high priced
variable pitch stuff like MT to equal the performance of a well matched
fixed pitch prop.
What is well matched? If you are running
an RD-1B the static rpm should be 5100 - 5500. With the RD-1C it
should be 5900 - 6300 rpm. If you get less than that, it
isn't a well matched prop. This also assumes that the engine is
performing up to par of course. The exact number depends on what you want to
optomize, climb performance or cruise economy.
One more caveat:
If you are putting it on a plane with a cruise speed below ~ 150 MPH, the IVO
also works on tractors as well. On my RV-4 the IVO cut top speed about
15 mph. and around 10 mph from cruise compared to a well matched fixed pitch
prop.
Tracy
On Wed, Mar 11, 2009 at 12:41 AM, John Slade <sladerj@sbcglobal.net>
wrote:
>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" <sladerj@sbcglobal.net>
To: "Rotary motors in
aircraft" <flyrotary@lancaironline.net>
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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