Drag Test

Jon Finley <jon@...>


I too am happy to collect some data. However; I'm afraid that figuring out what the test should be/how to conduct it is over my head. I have tried (a couple of times) to type up what confuses me and I just end up confusing myself (a good indicator of "over my head").

For test development purposes:
1. Suggest something over 7000' DA. I can get that low now (cold temps) but in a few months that will be DA at ground level.

2. Suggest the Paul Lipps approach to determining TAS. In my opinion, it is very simple/easy to do.

Inaccurate information REALLY bugs me so would suggest enough "controls" be in place to prevent bogus data from being included.


Jon Finley
N314JF - Q2 - Subaru EJ-22

-----Original Message-----
From: "Mike Dwyer" <mdwyer@...>
Sent: Tuesday, January 4, 2011 6:47pm
To: Q-LIST@...
Subject: Re: [Q-LIST] Re: Benefits of streamlining Happy New Year

I hate to be so negative but the prop on my 0-200A starts to windmill
above 120mph... So ya can't actually stop the prop.

Maybe if the test was set up this way. Start with a 140 MPH TAS at
7000' density altitude. Measure the speed (GPS) on a 120, 240, and 0
heading level. Then on a 0 heading measure the speed at a 200 FPM
descent without touching the power. Then you could probably get a good
idea of each type's drag with a small error based on engine/prop type.
This might also be a good way to see what your drag reduction fixes
actually did for ya if you run the same test after each improvement...

I'd be willing to collect that data as long as we know what to collect.

Mike Q200 N3QP