From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Cooling Inlets
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
References: <list-141306@logan.com>
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Date: Mon, 12 Jul 2021 23:31:32 -0400
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Thanks Marc.

It just looked like Ed Anderson was bored (complaining about no traffic 
on the list).
He used to revel in diving into such papers and math :)

Finn

On 7/12/2021 10:16 PM, Marc de Piolenc piolenc@archivale.com wrote:
> 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 
> K�chemann 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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