From: "Marc de Piolenc piolenc@archivale.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Cooling Inlets
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message-ID: <a5697362-9d97-6362-9102-d74672a2fdcd@archivale.com>
Date: Tue, 13 Jul 2021 10:16:12 +0800
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Wish I could dive into this, because it's something I will have to look 
into for the book project that I am working on, volume 2 (Cooling 
Systems Design) of the ducted fan book series. Right now I am hip-deep 
(when there's time) in ejector design.

Can't though - while dreaming of great things I have to earn my living 
from day to day as a free-lance technical translator, and I am getting 
an influx of work, with deliveries extending to the 22nd (so far).

In addition to Miley's report, you might want to get a copy of Küchemann 
and Weber's Aerodynamics of Propulsion, which is the basis for Miley's 
work. It might help you decode Miley's train of thought.

If you can get a precise definition of each parameter, preferably in 
terms of other parameters and variables, you will be on top of it. In 
researching ejectors, I was stumped for months by two NACA reports, 
which seemed to have two completely different values for the same 
parameter of the same engine. It was resolved by careful reading of the 
definition presented in one report, which indicated that one version 
covered ONLY the exhaust stroke, while the other averaged the value over 
the entire cycle. Oof.

Marc de Piolenc

On 12/07/2021 2:12 am,  wrote:
> So Ed, you're bored?
> 
> Want to take a stab at helping me understand the below graphs and how 
> they lead to the selection of the optimum outside/inside lip radius ratio?
> 
> I understand that Cp is pressure coefficient, pressure relative to other 
> pressures in the vicinity.
> 
> Not clear to me if we're looking for positive or negative Cp inside the 
> diffuser, I assume positive? (Converting airspeed into pressure)
> I also assume we're looking for a profile with maximum Cp over a wide 
> AOA range.
> Why did they pick A-20 and Vi/Vo = 0.4 for figure 36d?
> Aren't we shooting for a Vi/Vo of 0.2 or better? (slowing 100 mph down 
> to 20 mph)

-- 
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