Posted by basicguy |
Dec 28, 2014 @ 05:30 PM | 1,926 Views
I had some 5/8" white foam board so I laminated two layers together with some 3M Super 77 spray. Made a pair of wings 2' long each.
My first fuselage was two layers of the same scrap foam. It would glide well if the conditions were just right. Throw too hard and it would stall. Was very sensitive to the 5 mph wind. It did glide with wings level most of the time.
I felt like I was not getting enough speed without getting too much lift. The overall weight was 90 grams and 65 grams without the nose weight.
I rebuilt it with an old aluminum arrow shaft and moved the wing to within about 3" of the front. It took quite a bit of weight to balance the plane. 3 half inch nuts and a 3/8" nut. Wow was I impressed the gliding speed went up a bunch but the lift was still there. It has 3 oz per square foot main wing area. The initial incarnation had 2 oz/ sq ft. Also had a body frontal area about 2 square inches more than this version does.
The smaller glider still flies like it did. That is to say that it has one very slow speed to it. Next I plan on moving the wing forward on a more slender fuselage and adding nose weight. All up right now it weighs about 20 grams.
I have not taken pics of the new beast. Once I get these to glide well, will consider a powered version.
Posted by basicguy |
Dec 26, 2014 @ 08:11 PM | 2,512 Views
I am feeling more confident. After success with my first trial. I decided to scale up a new Clark Y template. This one is about 6 1/4" at the base. The wire is suspended 5' away. If I make a wing section with a 30" length it will give me a wing area of about 278 sq inches. I really made the new template a lot smoother now that I know I can do it.
Made a few scrap wings from some one inch blue board.
I want to get get some experience and decide what airfoil I want on a larger machine before I fabricate a 10-12" base wing.
Have to get my flying skills built up. But that is another story.
He is using but one template and a fulcrum, instead of the usual two templates and C shaped machine. His machine makes an aero surface all in one cut. You hold the hot wire by a T handle. The nature of the technique is that it gives you tapered wings that vary depending on how long the wire fulcrum is from the template. I have mine set at about 39.37"
I think I may have improved on David W's technique by screwing the template on a plywood mount then clamping it to the table. I used a piece of Formica laminate for my template. I glued on a paper diagram and cut out the shape on the formica accurately. I also didn't split the template but run the wire through the template before starting. The Foam is sandwiched between the plywood mount and another board which I place lead weights over to hold things steady.
I had some solid core .023" steel MIG wire and used my 2 amp battery charger for a power supply.
I made several right wings then removed the template and turned it around and made left wings. I used scrap pieces of foam that were in my attic.
My first few cuts were not as good as I did after a bit of practice. My template is smaller than I would like. Am going to build another larger template.
My wife made a foam body and we glued the wings on. (They have a chord to span ratio of about 5:1) Balanced the plane with a penny. Had several decent flights. Something that made for a nice Christmas afternoon.