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-   -   Dumb question? (https://www.rcuniverse.com/forum/rc-gliders-sailplanes-slope-soaring-112/485664-dumb-question.html)

Skycam41 01-16-2003 05:55 AM

Dumb question?
 
Perhaps this is a dumb question but it is one that I do not have the answer to with my limited glider experience so I will ask anyway!

If all variables are equal, which glider would fly better, a 2M or 100" plus. Meaning that you are flying the same time of day, same piloting skills etc, would a larger or smaller glider stay up longer or does the size make no diff? Just one of those inquiring minds want to know questions.

Cheers

Mike

BMatthews 01-16-2003 08:04 AM

Dumb question?
 
In our RC Gliders size DOES matter. To lead off the long list of advantages they have more efficiency due to the larger Reynolds number range they fly in. If this doesn't mean much it's basically the measure of how efficiently the air deals with our models. Larger "fits" the passing air better and so the wings perform better in every way.

Now add to this the higher launches because the weight and drag of the line is not as large a percentage of the model. The fact that you can range out farther before you hit your limit of visual perspective and you've got some pretty good reasons.

This isn't a small advantage either. There's a noticable difference going from 2 meter to 100 Standard class and up to open class. Even there you can see the difference between the 110 to 120 inch and the 130 to 140 inch open designs.

I'd say from what I've seen that it's safe to say there's about a 25% to 30% advantage between a 2 meter and a 110 to 120 inch open class design in terms of flight times flying in marginal air where the models have to struggle to stay up but don't quite make it...... I had to set the conditions that way because if there's decent thermals then they are all good.... :D

Jack Hyde 01-16-2003 01:55 PM

Dumb question?
 
I used to take one 3m and one 2m sailplane with me when I flew and fly each in the same conditions. I did this many times and found that the larger planes produced longer flights by a clear margin. The smaller planes get hard to see pretty quickly too. I usually take 2 3m planes when I fly now.

Skycam41 01-16-2003 02:39 PM

Dumb question?
 
Thanks for the response, I appreciate the answers.
Cheers
Mike


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