REFLECTOR: Prop size

Mon Oct 12 13:34:00 CDT 2009

Thanks Kurt, Chuck and John. I'm gonna bolt this new prop on and go for it.
But not quite yet - still plenty left on my to-do list. One nice thing is
that Catto will whittle down the pitch at no extra charge if testing proves
changes are needed.

Dennis

On Mon, Oct 12, 2009 at 8:07 AM, <aminetech at bluefrog.com> wrote:

> The other thing is that the IVO is pitch adjustable, meaning that identical
> performance is possible at different prop lengths (to a degree).  After an
> inch was removed from each of my blades I saw no difference in operation.  I
> simply used less pitch adjustment at the fine end and a little more at the
> coarse (cruise) end.
>
> John
>
> --- cjensen at dts9000.com wrote:
>
> From: "Chuck Jensen" <cjensen at dts9000.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Subject: Re: REFLECTOR: Prop size
> Date: Mon, 12 Oct 2009 07:47:52 -0400
>
> Dennis,
>
> Length shouldn't, isn't, necessarily corelated to speed.  More than a few
> have reported that after an 'unscheduled' shortening of the prop, they were
> actually faster afterward.  Long props definitely make more noise, but not
> always more thrust.  Despite all the study, there is still a certain art
> (some call it Black Magic) to prop design and mating to a propulsion and
> airframe system.
>
> Chuck
>
> -----Original Message-----
> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]*On
> Behalf Of *Dennis Martin
> *Sent:* Sunday, October 11, 2009 7:22 PM
> *To:* Velocity Aircraft Owners and Builders list
> *Subject:* Re: REFLECTOR: Prop size
>
> Kurt,
>
> Craig modeled my prop from his experience with other Chevy applications. I
> still wonder, however, if 68" maximizes my HP. Guess we'll just have to race
> sometime. There's no question that prop designs are influenced by black
> magic. So, why can't Craig make my prop longer?
>
> Dennis
>
> On Sun, Oct 11, 2009 at 3:40 PM, <nmflyer1 at aol.com> wrote:
>
> Dennis,
>
> Well.. Good question, but I'm not the guy to ask. I recall that, when
> trying to find a good prop for my V, most prop makers didn't have much idea
> what to do unless they had tried it many times before.
> Mine is an IVO as you know (the CS Magnum version). He was the only one at
> the time that asked knowledgeable questions, thought about my install, and
> decided what would be best with what we had to work with. Because of our
> tremendous V-6 torque due to the redrive, he said that I would need a BIG
> PROP to use my power efficiently.
>
> Due to my density altitude and power, I decided to go with the IVO Constant
> speed. I also can trim the blades if need be without much hassle. Easier to
> trim than lengthen for sure.
>
> If he can "re-cut your blades longer",  he's a magician :)
> Craig would definitely be the one to ask on width versus length (prop wise
> at least :)
>
> If I remember right, I have almost 10" of clearance from the hangar floor
> to the prop (unloaded). Looks close to me, but apparently it is fine for a
> Velocity
>
> Kurt
>
>
> -----Original Message-----
> From: Dennis Martin <dennis.doc at gmail.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Sent: Sun, Oct 11, 2009 1:29 pm
> Subject: Re: REFLECTOR: Door strut review
>
> A 76" prop? Size matters, eh? Now we all have prop envy. I made a point of
> telling Craig Catto that I had lots of ground clearance, but I did not
> dictate the length. I assumed he would take advantage of my extra height, at
> least the same as yours or more (I've forgotten exact clearance). He went
> for a wider paddle and kept it at 68". Which is better? I haven't installed
> it. Should I consider having him re-cut my blades longer?
>
> All the best,
> Dennis
>
> On Fri, Oct 9, 2009 at 10:24 PM, <nmflyer1 at aol.com> wrote:
>
> Al,
>
> My doors do not go over center to the point where there is a noticeable
> downward positive force on the doors. You can push them downward and let
> go.. then they just stop. I think I found the sweet spot for my design, in
> that you can gently push them upward and they will stay where you put them.
>
> Honestly, after paint, door panels & upholstery, another few pounds of
> force could not hurt, but I have not found it necessary.
> I believe my design is aesthetically better than the factory one, but folks
> over about 5'10" may have to duck a bit. A small price to p ay for such a
> nice looking aircraft.
>
> One more thing, I think my Velocity is taller (at the door base) than most.
> That is to accommodate the 76" 3-blade prop I have to (hopefully) handle my
> engine install.
>
> Patiently waiting for a nose gear
>
> Kurt Winker
>
>
>
> -----Original Message-----
> From: Al Gietzen <ALVentures at cox.net>
> To: 'Velocity Aircraft Owners and Builders list' <reflector at tvbf.org>
> Sent: Fri, Oct 9, 2009 11:34 am
> Subject: Re: REFLECTOR: Door strut review
>
>
>  Al,
>
>  Well I have both doors off right now, so I'll have to wait a bit to get
> you a complete picture. here's what I did though:
>
> Kurt;
> Thanks – I understand what you did on the reinforcing.  Mounting the strut
> bracket further down on the door frame gives it better leverage on the door.
>  Does it go over-center before the door is closed?
> Al
>
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> Dennis
>
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>
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-- 
All the best,
Dennis
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