From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>
Received-SPF: pass
 receiver=logan.com; client-ip=66.163.184.43; envelope-from=finn.lassen@verizon.net
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Inlet radius ratio
Message-ID: <25e95f81-0618-b731-00de-4e1233540655@verizon.net>
Date: Tue, 7 Jan 2020 11:56:42 -0500
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
References: <25e95f81-0618-b731-00de-4e1233540655.ref@verizon.net>
Content-Length: 734

Tracy reported a marked increase in cooling when changing the 
inner/outer radius of the duct inlet. The outer radius of the lip should 
apparently be greater than the inner radius of the lip. He got the 
optimum ratio from an NACA paper, but don't remember which.

I think the goal is maximum pressure recovery at low speeds (100 mph) 
and high angle of attack and of course minimum drag at low and high 
speeds (output cowl flap to lessen flow at high speeds making the air 
flow easily around the inlet and cowl at higher speeds).

I've been trying to locate that paper but keep finding papers on turbine 
inlets and supersonic inlets.

Does anyone know what that NACA paper may be? Or even just the optimum 
radius ratio?

Finn