http://www.ae.uiuc.edu/m-selig/ads/afplots/fx60126.gifyes i like that one too.and thank you for your reply , my diarys are not invisable after all.
"I guess I have trouble seeing what you want to accomplish with this project. Do you have a real objective or is it fun and games or perhaps 'foam art'? I don't see how testing a portion of a blade would give any reasonable results that you could extrapolate to the finished product"
if you look at it this way , testing the root section and subsequent ones should produce results at least as fast as the final (target) rpm. for a given wind speed.
and since they did not , i knew something was wrong.
lol foam art perhaps , but there IS a real objective , i've got 48 neos just iching to be powered by these things.
"In your previous post (Got Root?) you stated that the rotor diameter was to be 9.8' but later in the same post you said it was 7.75'. You also said that the first station was located at 8" radius and assuming the first station was at 10%, that doesn't translate to to either diameter. Color me confused."
i was just thinking about that last night ! , that i should bring them in , closer to the hub.thanks for pointing that out.
as for the final dia i can see where the confusion comes in ..., part of the problem was the foam was'nt as thick as i thought it was , it turned out to be only 7/8" thick , not the inch i thought it was 
and since i allready have all three 33 percent done and the other sections for one 88 percent done , there is no way to change the ones i've allready finished( by adding another layer of foam per section...)
"I didn't see mention of any sort of spar system to be used. Unless you intend a very thick glassing job, it doesn't look to me you would have the necessary strength without spars. Did you allow for the skin thickness when cutting your airfoil templates? Not doing so will change the airfoil for a given chord. What is the L/D and Cl of that airfoil? For decent efficiency, you should shoot for a L/D~100 and a Cl of 1.0 or better. One of my favorites, the Wortmann FX60-126, meets these requirements."
all very good questions, and frankly i have no idea what the lift/drag is for the airfoil i'm using
nor the coefficient of lift. sorry.anyone know??
as for the strength , yes i'm going to glass/epoxy them and no i did not allow for the skin thickness when cutting the sections, they're just going to have to be a little bigger , thats all . as Flux said , blades can be very forgiving , i guess we'll find out
"The inner 20% only contributes 4% of the rotor power, 25% - 6% and 30% - 9%. That's a lot of extra material and work for little return when you consider the large inner chord. Also, progressive taper and twist only buys you a few percent (perhaps 5%) over linear taper and twist which is a whole lot easier to make. If you went linear, you could really put that hot wire cutter to good use. Tacking a root and tip template on the ends of your foam blank to serve as cutting guides, you can cut the whole thing with one pass (assuming your wire is long enough). Spar slots can also be put into your templates."
i couldnt see making a foam blade without the twist and taper ( wood yes ) but the foam would probably ( maybe) flop around , the twist and taper adds much more strength than you might imagine.
i still have those very , very large foam pieces, four - 8'x 9" x 4" , a truely awesome find that was..
so if you left off the inner 30 % would you be leaving out 19% of the total? i'm a little unsure how that works?
