Mailing List flyrotary@lancaironline.net Archived Message #49831 previous message next message back to list

From: "MONTY ROBERTS" <montyr2157@windstream.net>
Subject: Re: [FlyRotary] Tiff to CAD Software
Date: Fri, 29 Jan 2010 10:18:16 -0600
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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Thomas,
 
Not trying to rain on your parade, but why do you think that something designed to cool a 1500 hp WW2 fighter at speeds over 300 mph and then scaled to fit in your airframe is what you need for your application?
 
You should calculate what your particular situation needs and go from there. The math is not that hard, in fact I think Ed has a spreadsheet he would probably be willing to share if you asked nicely. I think he would even run some numbers for you. If you want to make it look like the P51 installation fine, but size all the radiators, inlets and exits for your speed, altitude and power levels. Then draw the P51 like scoop around that and see if it still fits.
 
1.) determine how much HP you plan to make continuously.
2.) figure out how much heat will be rejected at that HP.
3.) figure out how fast your airplane will go with that much HP.
4.) size inlet and exit accordingly.
5.) Check over range of altitudes repeat step 4 and 5.
6.) look at hot day takeoff and climb. size max exit opening for that.
7.) compare your results to the other flying examples closest to your application for a sanity check
8.) If you are the outlier you better understand why or start over
 
I would look very closely at what Al G has done as well as others successfully flying canard aircraft with rotaries. They have much more in common with your application than the P51.
 
Monty
 
 
----- Original Message -----
Sent: Friday, January 29, 2010 9:36 AM
Subject: [FlyRotary] Tiff to CAD Software

In my efforts to transpose the TIFF image format of a Microfiche image of a hand drafted blue print of the P-51 scoop and related drawings.

 

As you might imagine, just dealing with the grainy images is in itself somewhat difficult but trying to translate it into a CAD drawing is even more daunting.

 

SOLUTION:

I scratched up a software program yesterday that will allow me to do the following.

·         Import a graphic file.

·         Determine the scale (pixels to inch)

·         Select a start point (lower left corner of my converted image)

·         Allow me to trace the drawing and convert it to a CAD script using mouse clicks to define points of the drawing.

 

It’s more of a prototype at the moment but I can make it into a deployable application once I make a few enhancements. I tested it on three of the images yesterday and totally blew through the process creating scripts for the radiator exhaust door, oil cooler exhaust door, front profile of the scoop (oil cooler forward) and all the associated bulkhead drawings in a couple hours.

 

The end result is I can scale the scoop drawings at roughly 61% and have a full size drawing to use as templates, etc. for my application. I plan of plotting these out full size this weekend and start on the actual fabrication of the scoop & diffuser.


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