ORIGINAL: Soarbird
Thanks for the responses so far. One of the guys here has a Bubble Dancer but does not seem to place too well at the altitude we fly at here which is 5,700 ft above sea level. This together with the high summer ambiant temperatures gives it's own density altitude problems in terms of thin air.
The top three local competition airfoils seem to be MH32, RG15 and SD7036. The former two are fitted to F3B type glass ships but the SD7036 is fitted to a wide variety of glider types and sizes from 2 metre to 3.2 metre span. I have an own design 2.0 metre glider which uses the SD 7036 at 11.8% which appears reasonably versatile but not as good as a comparable plane at our club which uses the FX60-100. I have another own design 3.1 metre glider which also uses the FX60-100 and is a sedate flyer but at twice the wing loading of my new design.
So confusion continues to reign. Any comments??
Best wishes,
Soarbird
OK, so with the one bubbledancer you've seen, are you sure the pilot is getting the most out of it? What about the competition? What it beating it? You altitude difference makes less than 15% difference in reynolds number - which means you should be flying 5-10% faster. If the guy is trying to fly too slow it'll be bad.
The RG15 is a fast flying airfoil so it's not really for a floater RES. The MH32 is fine, and so is the SD7037. You can use those and your glider will be very nice. However, you asked what's best with a wide speed range. The Drela airfoils have been custom designed for their operating Re and have speed range that beats anything else. Where most people build a sailpane wing with a single airfoil over the span, Drela wings typically have 4 different airfoils customized for the different Re at different chord lengths. If you think your Re is lower because of altitude, select one of the Drela airfoils that normally would be used for a 7" chord and use it for your 10" root. Adjust other stations accordingly.