Re: 40% Stab size or 20%?

From: John Kagan <john_kagan_at_hotmail.com>
Date: Sat, 23 Oct 2010 21:56:43 -0000

Which row is Cl in? I see Coeff of lift for the stab in row 36, but I assume you are talking about the Cl for the wing, or maybe even the total Cl?

It will be great if Cl going unreasonable is the flag that the other parameters are unrealistic. That will make it more fun to play around with.

I'm very impressed with this spreadsheet (and its other incarnations). I guess it's a bunch of relatively simple calculations layered on top of each other, but the end result is pretty spectacular - to me anyway.

--- In Indoor_Construction_at_yahoogroups.com, Don Slusarczyk <don@...> wrote:
>
> Yes but look at the Cl values generated with such high posts, I believe
> they go very high. Also be aware that the formulas used to calculate
> downwash are formulas for full size aircraft and some effects/assumtions
> used to make those equations may not translate well to our lower speeds.
> But it was all that was available. Someone needs to put an indoor model
> in a wind tunnel and get some data on downwash angles in regards to
> wing aspect ratio and angle of attack then the program can be fine tuned
> more. Treat the spreadsheet as living document and can always be
> improved and refined especially as rubber and VP technology improves.
>
> I have found the CG and SM calcs to be very helpful in many events.
> Flight times especially for models like F1D, HLS, Int Stick, and EZB
> were all pretty much as expected. Some events are a bit off in predicted
> flight time and further study is needed on those models that fly at
> faster speeds and use lighter rubber etc to get better estimates on
> flight prediction.
>
> Don
>
>
> > This kind of thing still amazes me. Now I've got to start playing with it again.
> >
> > I gave up last time when increasing the wing post length on one of the spreadsheets kept improving the time, even past 50".
> >
> > BTW - I added a row on my copy for "Approx VP time corrected for low rubber ratio", "=B64*B84". That made the F1D-55 times for my current model pretty accurate.
> >
> > ---
>
Received on Sat Oct 23 2010 - 14:56:53 CEST