Tom,

What engine/PSRU are you planning to put in your Venture?  It seems to me that you are going to have to do some thinking about this combination if you plan to use a Mazda engine.

 

If you use Tracy’s RD1-C, you will be limited to about 2450 rpm prop speed (7000 engine) on take off and about 2100 rpm prop speed (6000 engine) in cruise.  That means a heck of a lot of pitch to get a cruise speed of 240 knots!  I think that would work out to around 138 inches of pitch.  On takeoff, you would probably think the prop was feathered!

 

Tracy’s RD1-A or B has a ratio of 2.17 and turns backward to normal aircraft, but I don’t know if he has them rated at high HP.

 

You may want to try and buy a Mistral PSRU so you can fit a constant speed prop of some kind.  I don’t know if that is even possible??

 

I hope this msg will  generate some comments from people with more knowledge about this than I and maybe they will have some nuggets you can use.

 

Bill B

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Thomas Giddings
Sent: Thursday, April 26, 2012 7:14 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Fixed Pitch props.

 

Thanks for your info. I did contact Craig Catto and here is his response:

 

Hello Tom,

That is going to be quite a challenge to fit.   We make them for the 540 Berkut, and that is about a 285mph aircraft and have done one for a E-racer turbo 540 at 350HP doing over 300mph.

I do not think I want to challenge the auto conversion, just the power curve many times seems hard to fit. We know the curve of the Lyc engine very well and so not such a big deal to fit in these types of applications.  Easiest way for you to fit it is probably with a MT.

All the best,

Craig

 

I was surprised at his answer as i thought he did Tracy's prop. The speed of the Venture will not be that much more then what he described. It may be the high HP I will be using.Any more suggestions would be appreciated.

KIND REGARDS

Thomas Giddings

n360tg@earthlink.net

727 858 1772

 

 

 

On Apr 26, 2012, at 1:28 AM, William Jepson wrote:

Another possibility is Senessich (never could spell that), they have a new ground adjustable prop. Carbon blades aluminum hub, which is supposed to be designed around RV speed and HP. They are supposed to offer a 2 and 3 blade option. Bill Jepson

On Apr 25, 2012 8:53 PM, "Michael McMahon" <afm528@gmail.com> wrote:

I’ve been thinking along the same lines.  The one person I’ve heard of often as a potential builder is Craig Catto, www.cattoprops.com .  Last time I looked his props were around $3,000, I think, but I have no idea if that is current.   There is also a new possibility, which is to have the prop manufactured on a resin printer and then wrap it in carbon fiber.  I’ve done a little research on that front and spoke to a manufacturer last year at the CAFÉ Electric Flight Symposium (this weekend in Santa Rosa!) who confirmed that it’s possible and is already being done for military drones.

 

Please post your findings!

 

Thanks,

 

Mike

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Thomas Giddings
Sent: Wednesday, April 25, 2012 6:57 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Fixed Pitch props.

 

I am curious what you folks might recommend for a fixed pitch prop builder for my project. I will have a lot of excess power and do not think it would be as difficult to get an acceptable level of performance with a lot less money and simplicity. Your thoughts

KIND REGARDS

Thomas Giddings

n360tg@earthlink.net

727 858 1772