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Rusty,
That
sounds like a good plan. I think that IVO has one person that is
knowledgeable. The first person that I talked with didn't seem to know
much, so I ended up talking with the head guy. I don't remember his name,
but he did at least know what he was talking about, and was pretty familiar with
the rotaries, and Cozy's (or maybe just pushers in general). In fact, he
was the one who said that he would include the spacers in case I wanted to go to
a 2 blade configuration to increase top speed.
There
is a significant area in the center that doesn't have much/any pitch. I'm
sure in your RV, it would have been a issue. I really want the in flight
adjustable option, and I don't want to pay $10K for it. That is what
attracted me to the IVO. I did notice that the price went up by $400 on
the electric pitch unit. I guess I should have bought it when I bought the
prop.
I
spent all day yesterday shooting primer, and then sanding what I primered
yesterday. I spent allot of time under the plane sanding overhead. I
can't tell you how enjoyable that is. The only good news is that primer
definitely is easier to sand than micro.
Steve
Brooks (really sick of sanding)
Cozy
MKIV 13BT
I agree that with
the pusher, the air is blocked from the center portion of the prop, so the IVO
really doesn't hinder top end speed. It may on the RV.
The IVO Magnum
comes with 2 different ranges on the pitch. I have the high pitch blades
which is what they recommend for my plane. I believe that the pitch
range goes from something like 40-45" on the low end, up to something like
105" on the high end of the pitch range.
Steve
Hi
Steve,
I called IVO, and of
course they've never heard of such a thing as their props
causing drag at high speeds. Imagine that. Tracy
probably just made that up :-) Anyway, they didn't really inspire
me with confidence that they knew much about props. Mostly, they work
from numbers that they have archived, and give recommendations based on
those. Their best recommendation was for a 3 blade,
68" Magnum, standard pitch prop. Since I'm planning to run it to
3200+ rpm, they said I don't need the high pitch
range.
I took a closer look at my
Warp Drive prop (3 blade, 68") today, and find that the hub area should create
far less drag than a typical IVO. Since IVO didn't have any
significantly different recommendation from what I already have, I'll probably
continue working with the Warp to see what I can get. In fact, I took 3
degrees out of the pitch today, to get the RPM up.
After thinking more about
it, I really can't make any final decisions until I get the wheel pants and
gear fairings on. I may also need to close up the rear of the cowl
cheeks, though that might have to wait until I can do some testing in 90-100
degree temps to make sure the lower opening is adequate. I will also
need to send the Warp blades back, so they can taper them. Only then
will I know how they work when they're optimized.
Cheers,
Rusty (I need more
RPM Scotty)
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