Re: Sparrow strainer stall


David J. Gall
 

Jay,

Nice work. Your modified LS1 elevator would go a long way toward reducing the workload required of the sparrow strainers, but you’d still need something like sparrow strainers to push the TE down for normal ops. The Roncz airfoil’s elevator is intentionally designed with a slight “reflex” on the trailing edge just so that it won’t need sparrow strainers or trim tabs. I suppose that with a little more work you could achieve the same with your modified LS1 elevator. 

Keep at it!

(BTW, what software is that?)


David J. Gall

On Mar 24, 2020, at 8:38 AM, Jay Scheevel <jay@...> wrote:



Hi Bruce,

 

A few years ago, I tried modeling the existing LS1 and only changing the shape of the elevator to try to eliminate the strong asymmetric pressure on the trailing edge (which is the reason you need the sparrow strainer). The reasoning was, that maybe someday, I would build a new set of elevators with the revised shape and leave the sparrow strainer off because it would not be needed. Here is a comparison of the pressure distribution on the the original LS1 for 0,3,and 6 degrees AOA (first graph) and for the same airfoil with the revised elevator (second graph), which would fit in the same slot. Note the difference in pressure on the top/bottom near the trailing edge. The modified version provides slightly lower lift than the original.

<image002.png>

<image001.png>

<image005.png>

<image006.png>

 

 

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Bruce Crain
Sent: Monday, March 23, 2020 9:04 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

 

I see no Sparrow Strainer!  We've been "punked"!  Shoulda, Coulda Woulda!

B

Please note: message attached

From: "Jay Scheevel" <jay@...>
To: <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow strainer stall
Date: Mon, 23 Mar 2020 18:13:28 -0600

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