Mailing List flyrotary@lancaironline.net Message #27056
From: Dale Rogers <dale.r@cox.net>
Subject: [FlyRotary] Re: flyrotary_Web_Archive Re: Banishment
Date: Wed, 19 Oct 2005 11:57:51 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Thomas,

   I'm having a little trouble identifying whether or not
you're just playing "devil's advocate".

   On the assumption that you are completely serious, it's
worth considering the following:

[1] WRT canard pushers:
  A - Burt Rutan started out with a P-51 style scoop on the
Vari-EZ.  IIRC the early Long-EZs also had them.  He later
changed to the NACA scoop because it was more "efficient" in
some combination of cooling efficiency vs. drag.

  B - Nat Puffer rescaled the NACA scoop such that it does,
in fact, provide sufficient cooling for a 180 HP Lycosaurus.
His design will go 200 MPH on less than 13 gal/hr - which
suggests a low-drag desgin.
see:  http://www.cafefoundation.org/aprs/Cozy%20IV%20APR.pdf
That same scoop will also provide sufficient cooling for a
200+ HP Turbo-charged rotary even routed through multiple
heat exchangers.  

[2] Sound empirical evidence ALWAYS trumps theory.

[3] Good engineering practices suggest that it is unwise to
experiment with too many things at once.  In the event that
something goes awry, one may encounter considerable difficulty
in ascertaining *which* component or subsystem caused the
problem.  If one wants to experiment with improved cooling
systems, it would be wise to start from a solid baseline of
a system that is _known_ to work, and change one item at a
time.  

Good luck.


Dale R. ......................|......(___.......|
COZY MkIV-R13B #1254 .........|----==(___)==----|    
Ch's 4, 5, 9, 16 & 23 in progress ..o/ | \o
http://www.canardzone.com/forum/showthread.php?t=1388
(Cedat Fortuna Peritis)


> From: "rijakits" <rijakits@cwpanama.net>
> Date: 2005/10/18 Tue PM 11:26:36 EDT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: flyrotary_Web_Archive Re: Banishment
>
> Hi John,
> it was me, Thomas J. babling below, don't blame Monty for it!
>   ----- Original Message -----
>   From: John Slade
>   To: Rotary motors in aircraft
>   Sent: Tuesday, October 18, 2005 10:25 AM
>   Subject: [FlyRotary] Re: flyrotary_Web_Archive Re: Banishment
>
>
>   Hi Monty,
>   ( I admit I am NOT a fan of EWP quite yet...., however stand to be corrected)
>   I think Rusty used one with success in hot weather. I'm also waiting to see
> the EWP prove itself, but at least over here we're open to the possibility.
>   I believe Rusty's system still kept the engine driven WP in addition to the
> EWP. Rusty?
>    # NACA scoops work: Well I guess you if you make them big enough
>   Let me rephrase, then. The Cozy plans NACA scoop is sufficient to cool a turbo
> rotary.
>
>    of course, BUT there are better and more efficient ways to get cooling air
> in!
>   I think, for a pusher, the NACA is the least draggy solution we know. I may be
> wrong.
>
>   But one should take advantage of his list of resources and really dig in
>   IMHO There's too much untruth and incorrect / unproven theory buried in the
> truth to make the exercise worthwhile
>   I am refering to the references to the books of Kuchemann & Weber and Kays &
> London. It is "hardcore" reading but at least some of it "seems to make sense"
> even for the layman.
>   Remember the inventors of the NACA-duct did recommend to NOT use it as a
> pressure-recovery intake (what we need for our our car style radiators)
>   Unfortunately they "look" rather sporty, so we fall for them....
>   Also even the P-51 style scoop doesn't do the best for efficiency. In one of
> the books it is mentioned somewhere (IIRC), but there were one or two testships
> with modified scoops (according to K&L I think....), which improved efficiency
> over the last production system. However that one was good enough, so the new
> one never made it to the masses and then WW2 was over and the jets on the
> doorstep.
>   Once you get really into aerodynamics concerning effiecient cooling, it starts
> to hurt seeing people fight for cooling but having bad/inefficient systems.
>   As mentioned before, for me the road will be the fun, not so much the
> destination, so when I get to it I will really enjoy doing lots of experiments!
>   Don't hold your breath though....:)
>   Now PL the pope, made me look at these books (actually only parts of it...).
>   Also remember (again...) these facts do not come from grumpy old man, but are
> facts from respectable sources - he just pointed the finger in the right
> direction.
>   # Earth round?? Obviously you never fell off the edge yet!! Actually it has
> the shape of a trochoid!! - bet you didn't know that!
>   I did say almost. :)
>   Right!
>   Regards,
>   John
>   Saludos,
>   Thomas


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