Thoughts on 7035 vs. 7037 Airfoils
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Home > Articles & Tips Index > Model Design > Thoughts on 7035 vs. 7037 Airfoils

[Courtesy of Martin Brungard mabrungard "at", July 1999 - as a reply to a series of discussions on the 703x series airfoils on RCSE]

There was one misconception in the original post regarding the merits of the 7035 vs. the 7037. In that post, the writer mentioned that he understood that the 7035 had a wider speed range and better L/D. The speed range part is correct, but the L/D of the 7035 is not better than the 7037.

I've done a lot of comparative analysis for the 7035 and 7037 and have found that the 7037 is actually a better thermal airfoil than the 7035, providing a better L/D and lower minimum sink. The advantages are minor. I'm relying on memory here since my comparison files are on another computer, but I seem to remember a L/D advantage of about 1 and maybe a reduction of 0.03 meter/sec in the minimum sink when using the 7037 on a 2 meter. These numbers could be way off here guys, so give me a break. I'll check the files next week, if it matters.

This is not to say that the 7037 has all the advantages when it comes to soaring. The wider speed range of the 7035 definitely comes into play when considering the launch. A properly designed aircraft that can handle a good zoom, can convert that wider speed range into a definite height advantage on launch compared to the 7037. At low lift coefficients (high speed flight), the 7035 is markedly more efficient. You should recognize that high speed flight normally occurs during launch.

My personal preference has swung to the 7035 for aircraft with full trailing edge control. That provides the ability to add camber to improve the minimum sink performance. Unfortunately, it still doesn't improve it to the 7037 level.

I find that the 7035 speed range is a lot more fun, but that criteria depends on the flyer's style. If a flyer is more comfortable with slightly slower flying aircraft(the 7037 still goes pretty good), the 7037 is going to better fit that style and provide a better flight performance also.

Martin Brungard Tallahassee, FL

"Meandering to a different drummer"

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