Thanks for the suggestions. This roll of mylar has been in the box for some time (couple of years) and took a hard set. Results so far:
Tape down the mylar and use a hot air gun - minimal effect Iron the mylar on the bench with a bunch of pressure - minimal effect and easy to scratch Reverse curl - minimal effect by itself Reverse curl (tight ~ 4" diameter) and hold with rubber bands. Then soak in hot water for several hours - works pretty good. They'll actually lay down on the surface now rather than curl into a cylinder. One more good soak ought to do it. No real problem with scratching this way either. Thanks for the many suggestions, - Dave R **** Re the other thread on weight/size - there have been a number of articles in RCSD on wing loading, planform selection and scale effect (Re) dating back at least 10 years. Martin Simons covered a lot of this and the Tech Topics column has covered it since Martin retired. Most recently some (incomplete) thoughts were covered on 2 meter design and planform vs wing loading vs airfoil selection. Best approach (my opinion) is to work through a polar calculation using either X-Foil or UIUC data for the airfoil. Then vary loading, aspect ratio, etc. to see the effects. Generally speaking, Re is a factor up to about 2M. After that it isn't critical. What you're really looking at is loading and planform optimization - primarily aspect ratio. Weight and aspect ratio (implied wing area) trade off in the 2M and up sizes. For a span limited class (such as 2M) there will be an optimum aspect ratio (~ 9 for 2M) for the typical weights we build. Build lighter and you've got more wiggle room. Build heavier and you better up the squares (assuming TD performance). Open up the span and you've got a lot more design room. If anyone wants the Windows-based polar program (written in VB6), I'll be happy to send it on a CD, including the airfoil files, compiled program and source code. Derivation of all the equations and input assumptions is covered in the RCSD columns. It's also covered in several other sites by Drs. Selig and Drela and is referenced in the UIUC and Princeton work published by Herk Stokeley. When all is said and done, this will only get you into the ballpark, After that, ya gotta go build and fly to see what will really happen. These types of calculation will tell you a lot about the speed/efficiency range but they can't tell you much about how it 'feels' in the air. - Dr. Dave RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
