Sailplane Calc Update

[CloudyIFR]

Sailplane Calc Now Available in Metric!

It is my pleasure to announce that with the help of Jaap Braam that all of my spreadsheets are now available in metric!

There are different downloads, one for the metric version and one for the original decimal version.

The original “Sailplane Calc” and “V-Tail Calc” have been updated as there was an error in Spiral Stability calculation on the Tail Sizing Checks tab. Thanks to A. Todd Jurhs for finding this error.

Flying Wing Calc is now available for wings with multiple tapers!
This spreadsheet uses the late Dr. Panknin’s formulas for calculating the required wing twist for a non-plank airfoil, originally for only a single taper wing and now available for up to three different tapers.
Note: I have not built or flown a model with more than one taper using this new spreadsheet.

Thanks to RCSD for publishing a tutorial on how to use “Sailplane Calc” in the April 2008 Issue; a link is provided on the Articles/Files tab of my new website.

I now have a dedicated website for all my contributions to the modeling community.

Please visit the new website for the most current updates:
www.TailwindGliders.com

Curtis
Montana

[BMatthews]

Thankyou for being generous enough to share these resources.

I'd also like to thank you for hosting the great Panknin spreadsheet file. I haven't been able to connect to b2streamlines for a couple of months now. Not sure if they are down for good or what. And that was my previous source for the excel version of Dr Panknin's great work.

I haven't run your spreadsheet so far but I'm hoping it'll have a lot of the same stuff that was in the old David Fraser program that I used to be able to run on DOS... remember that? :D

[MSelig]

The b2streamlines is up and running. It worked when I checked it now and it worked a week ago as well. It might be that your nameserver is not pointing to the right IP address.

[CloudyIFR]

I haven't run your spreadsheet so far but I'm hoping it'll have a lot of the same stuff that was in the old David Fraser program that I used to be able to run on DOS... remember that? :D

I'd be very interested in your comparitive results and your thoughts of my spreadsheet and any areas of improvement.

Yep, I do remember the old Fraser program. Times sure have changed! :)

Thanks
Curtis
Montana

[BMatthews]

The b2streamlines is up and running. It worked when I checked it now and it worked a week ago as well. It might be that your nameserver is not pointing to the right IP address.

But I'm doing a straight search in Google for it and it comes back with a broken link message. Oddly enough if I select the "view cached google page" option it presents the material with no issue.

[MSelig]

But I'm doing a straight search in Google for it and it comes back with a broken link message. Oddly enough if I select the "view cached google page" option it presents the material with no issue.

I assume you're trying this:
http://www.b2streamlines.com/

[Neil Stainton]

Thank you for your work. May I suggest an improvement? When communicating with others or publishing data (eg on my www.hyperflight.co.uk site), I usually need to give date in both metric and Imperial/American units. It would be very helpful if you could amend the Imperial/American units spreadsheet to also show the answers in metric units. Probably the converse isn't so important, but would also be nice.

Neil.

[BMatthews]

That's weird. Today it's working from your link as well as google and when I type it in directly. Oh well, all's well that ends well.

[CloudyIFR]

Thank you for your work. May I suggest an improvement? When communicating with others or publishing data (eg on my www.hyperflight.co.uk site), I usually need to give date in both metric and Imperial/American units. It would be very helpful if you could amend the Imperial/American units spreadsheet to also show the answers in metric units. Probably the converse isn't so important, but would also be nice.

Neil.


Sure thing, that's easy to do.

I'll fix all the spreadsheets to show both, it'll just be another column on the "Results" tab.

Thanks for the suggestion. They are what make the spreadsheets what they are!

Thanks
Curtis
Montana

[CloudyIFR]

Thank you for your work. May I suggest an improvement? When communicating with others or publishing data (eg on my www.hyperflight.co.uk site), I usually need to give date in both metric and Imperial/American units. It would be very helpful if you could amend the Imperial/American units spreadsheet to also show the answers in metric units. Probably the converse isn't so important, but would also be nice.

Neil.

Done!

Thanks Neil.

Curtis

[CloudyIFR]

There is an update to Sailpane Calc V-Tail.
The Vh/Vv values on the tail sizing checks tab had a large error.

Thanks to Sergey in Russia for finding this!

Curtis
Montana
www.TailwindGliders.com

[Montag DP]

Curtis,

I was fumbling around with your spreadsheet and found an error. It's probably not critical, but there nonetheless.

When I have a wing panel with a tip chord of 0, the location of the 25% point seems to get messed up. See the pictures below. The only difference in inputs between the two wings is that the first one has a 3rd panel tip chord of 0 and the second one has a 3rd panel tip chord of 0.0001. Notice the location of the 25% point moves back over an inch for the second wing (this is for a wing with an MAC of 9.36 - over 11% error).

Once again, probably not a critical error because usually people don't use a tip with 0 chord, but it's something to think about.

Dan

[CloudyIFR]

Dan,

Is your wingtip really zero and not .00001? :)

I know that I could add an IF statement and if there is a span number input then I can force Excel to use a tip measurement of say .000001 value instead of zero. This way the user can input 0 and he/she will never know.

I'll have to think on this one a bit, perhaps there's a better way.

Thanks
Curtis
Montana

[Montag DP]

Dan,

Is your wingtip really zero and not .00001? :)

I know that I could add an IF statement and if there is a span number input then I can force Excel to use a tip measurement of say .000001 value instead of zero. This way the user can input 0 and he/she will never know.

I'll have to think on this one a bit, perhaps there's a better way.

Thanks
Curtis
MontanaCurtis,

I think I found out what the problem is. In your cells that calculate the 25% point for each panel, you have a logic statement that sets the 25% point to 0 when the tip chord is 0. I'm not sure why you have that logic statement there in the first place, but that's where the problem lies.

I would have tried just taking that statement out to see if that fixes the problem, but I can't edit the spreadsheet. See picture below.

[Neil Stainton]

Curtis, I just downloaded and tried the latest version - it is excellent.

One improvement I would like would be cells to enter the model name and possibly notes. Although you can put these in the file name when saving the sheet with data, it isn't very convenient. It would be nice to show the model name in every entry sheet, and especially the results sheet.

BTW it looks as though the default data is based on the Bubble Dancer. If so the "Distance from Wing Trailing Edge to Fin Leading Edge " is incorrect - I estimate it at 33". Also I set the "Stabilizer Efficiency" to 0.8, which is probably more accurate for a Drela V mounted stab.

Neil.

[CloudyIFR]

Neil,

The names and notes are excellent ideas. I'll get that updated as soon as time allows.

I've also uploaded uploaded the spreadsheets to match the RCSD article.

Thanks!
Curtis