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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-4243608@logan.com>
Subject: Re: [FlyRotary] Ejector cooling
Date: Sun, 2 May 2010 06:59:17 +1000
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Marc,
I agree with your comments, but also can see where Mike is coming from - it 
horses for courses.
The complexity is doing it right and minimizing those drag issues. A simple 
tube in tube will give adequate -ve pressure, it seems you get better 
results if you use a  cone or bell shaped inlet -  as in the inlet manifold 
( which makes sense), and use a rounded exit lip ( as in the inlet) to 
minimize sharp edge turbulence, which also makes sense. Some may see this as 
overly complicated. However I see the benefits of a properly shaped exit as 
being as much a benefit as the inlet shape, so in that area alone it worth 
the discussion.
George ( down under)


> Mike Wills wrote the quorp  passages:
>
> "1) It adds measurable weight."
>
> Compared with what? What if a small addition of weight solves your cooling 
> problems and reduces cooling drag. Would you refuse to do it?
>
> "2) It adds complexity."
>
> How complex can a device with no moving parts be?
>
> "3) It adds noise (that alone in hindsight makes me glad I didn’t do it - 
> god knows I don’t need more noise)."
>
> No. Mixer-ejectors are used for noise REDUCTION. Successfully.
>
> "4) And finally, not a single person I spoke with noticed a measurable 
> improvement in either cooling performance or drag reduction after adding 
> an augmentor, or noticed a measurable reduction after eliminating the 
> augmentor."
>
> You seem to have consulted a very select group. In volume 2 of Alternative 
> Engines, page 139 et seq, Charles Airesman Jr. documents his experiments 
> with a very primitive ejector that generated 6 inches of water pressure 
> drop under shop runup conditions. That equates to a considerable shaft 
> power savings, more reliable ground cooling and a big step forward. And 
> this was Airesman's first attempt.
>
> There are other success stories if you choose to seek them out.
>
> Best regards,
> Marc de Piolenc
>
> Those seem like good enough reasons to pass on an augmentor unless you are 
> one of those guys that just has to prove it to yourself.
>
> Mike Wills
>
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