----- Original Message -----

From: wrjjrs@aol.com

To: Rotary motors in aircraft

Sent: Friday, February 29, 2008 3:10 PM

Subject: [FlyRotary] Re: New (old) guy on list

Greg,

The P-51 intake did several things that were unique before it came out. The stand-off for boundary layer hadn't been done that well previously. The proper KW bell shaped diffuser and very thick radiator and oil cooler. (Those probably wouldn't work as well for us, don't forget nearly 400 MPH) in a Lancair with a good setup you will run close to 300 so it is probably worth it. Don't forget that you would want to narrow up the front cowling since the heat exchangers aren't there to buy back some of the scoop drag. Don't for get to include the movable sugar-scoop/cowl flap at the rear. The literature I have seen says that the scoop didn't provide thrust, rather it almost broke even on drag, which is almost the same thing. One other item I saw about the P-51 scoop was that the shallow angle of the front of the opening wasn't a trivial thing. They did tests and found that the angle gave the best overall performance between climb and hig speed cruise. it was about 15° top side (fuselage side) forward. Get a book with a cutaway before you start you will be amazed how extensive the scoop is. Just a few items for your consideration. I think it is a good idea, but you need to know it my not be as easy as it looks, but then what ever is?

Bill Jepson


-----Original Message-----
From: Greg Ward <gregw@onestopdesign.biz>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Fri, 29 Feb 2008 8:50 am
Subject: [FlyRotary] Re: New (old) guy on list

I would also be really interested in seeing some others cooling solutions.  I was told that 40% of the Lancair's drag is in the cooling drag, and I am contemplating a belly scoop A la' P-51, and have created controversy about how much that configuration will add to the drag factor.  In other words, I might get great cooling at a slower speed?  Supposedly the P-51 configuration creates enough thrust to overcome around 90% of the drag created, but I would like to confirm that before I go through the process of designing and building the damn thing.......(:-)  Call me lazy...

Greg Ward

20B Lancair in Progress

----- Original Message -----

From: Mike Wills

To: Rotary motors in aircraft

Sent: Friday, February 29, 2008 7:26 AM

Subject: [FlyRotary] Re: New (old) guy on list

Well, it's not as beautiful as it once was. Had to add some ugly bumps for exhaust clearance. Finally threw in the towel on a clean oil cooler install and added a second scoop and stock RX7 cooler below the rad inlet.

 

 Can I attach pictures here?

 

 At the moment it appears during full power ground runs that I have excess cooling capacity, both oil and water. Never been over 180 on either. Which brings me to thinking (again) about oil/water heat exchangers. Has anyone successfully implemented one? If so what are you using? I may eventually be able to get rid of that second scoop.

 

Mike

----- Original Message -----

From: Russell Duffy

To: Rotary motors in aircraft

Sent: Thursday, February 28, 2008 8:57 PM

Subject: [FlyRotary] Re: New (old) guy on list

 I was on this list years ago when it first started up. Job change and other issues slowed progress on my project and I unsubscribed. 

 

Hey, Mike's Back  :-)

 

Good to hear from you again.  Can't wait until all the new folks see that beautiful cowl :-)

 

Cheers,

Rusty  

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