At 02:08 PM 7/05/2007, you wrote:
Anthony, Mike and All,
Many thanks for the input you are providing, it's the stuff I'm
looking for. I guess I should've painted my scenario in my initial
e-mail a little better.
I'm a performance XC pilot only (not interested in wave, local
soaring, etc), so want to get as much out of the glider as
possible. I have a huge 'to-do' list to make this LS1-f into a club
class weapon. So initially, I want to get the polar-curve of this
particular glider as is on purchase, then once the mods are done,
compare the results and see how much I've gained (for the glider,
and how much I've gained on the next guy, ie, points for
FREE). Obviously interested to see if there's a 'flat spot' on the
polar (as David Wilson has on his ASW-24) also..
So to answer the questions, and to ask a few more..
* I've got a L-Nav for the electrical vario system.
* I'll be taking maybe 1 x 10,000' tow, or; 2 x 5000' tows - undecided..
* In my spredsheet, I have calculated the pressure and density altitudes.
Not to sure really how they come into play though..
* I thought that all I'm interested in was the IAS, but how does the
TAS come into it..? To balance it all out I suppose..
* After hearing yours and other comments, I think I'll probably
shoot for a time interval at a certain speed. Should I do a 180*
turn, then do a 2nd run at same speed and average the two out?
Thanks again for your input,
Adam Woolley
LS1-f, GWR!
Adam,
If you are looking for the small differences before and after mods
are done, measuring the absolute performance is the worst way to go about it.
Have you got another similar performing glider to fly against? I
think Warwick club has a standard Cirrus doesn't it? Then do so and
note the differences. You can do this in real convective air too.
Then do your mods and repeat. If you've made a difference it should show.
All this can be done on cross countries against the other pilot.
Really this is what counts, not the absolute performance in still air.
The DLR performance testing uses a special DG300/17 that they have
measured the absolute performance of (hundreds of datapoints). It
lives in an airconditioned hangar when not being used for tests. They
fly new gliders against this and measure the relative performance.
Much easier for each new type and less prone to error.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
Int'l + 61 429 355784
email: [EMAIL PROTECTED]
website: www.borgeltinstruments.com
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