P
Peartree
One of my boys has an Estes Skywriter that despite its simplicity flies really well. Actually it almost flies too well, thats why hes on his second rocket since we watched the first fly over the trees at our launch site when he decided to try a C motor. Anyway, since he likes it so much I have thought that it would be neat if I could build one that took D size motors and higher, basically a MPR Skywriter. I took dimensions and drew up a simple dimensioned drawing for myself, then I entered all of these dimensions into Excel and scaled then by various factors based on available tube sizes. I figured that to jump up one motor size, I should jump up one major tube size so since the original is a BT50, I started with BT60 and I am still thinking about a 29mm BT70 or BT80 version.
Most of the parts are easily available and in fact, I had most of them on hand from various projects and leftovers fro the Box-o-parts contest. The nosecone was another story. I dont have a lot of those just lying around and this would be bigger than most anything I had built before. I exchanged emails with Gordon Agnello (aka Sandman) and he quoted me prices for both the BT60 version as well as the BT80 version. I decided that for now I was going to stick to the smaller one but maybe Ill do the BT80 over the winter or sometime next year.
After I received the nosecone I sanded out the few remaining toolmarks on this beautiful piece of wood with 300 grit sandpaper and used a foam brush to lay on three or four coats of spar varnish. I should mention at this point, that when Sandman found out I was building an upscale Skywriter, he offered to make the nosecone out of cedar instead of balsa if I wanted. We both thought that the wood grain on the cedar would work well for the pencil and so thats why I used the spar varnish, both as a waterproofing agent (three coats is usually good for boat parts that spend a lot of time underwater so I should be safe) and to highlight the beautiful wood that Sandman picked out.
With most of the parts in one place, the nosecone varnished and the motor mount mostly assembled, it looked like this
Most of the parts are easily available and in fact, I had most of them on hand from various projects and leftovers fro the Box-o-parts contest. The nosecone was another story. I dont have a lot of those just lying around and this would be bigger than most anything I had built before. I exchanged emails with Gordon Agnello (aka Sandman) and he quoted me prices for both the BT60 version as well as the BT80 version. I decided that for now I was going to stick to the smaller one but maybe Ill do the BT80 over the winter or sometime next year.
After I received the nosecone I sanded out the few remaining toolmarks on this beautiful piece of wood with 300 grit sandpaper and used a foam brush to lay on three or four coats of spar varnish. I should mention at this point, that when Sandman found out I was building an upscale Skywriter, he offered to make the nosecone out of cedar instead of balsa if I wanted. We both thought that the wood grain on the cedar would work well for the pencil and so thats why I used the spar varnish, both as a waterproofing agent (three coats is usually good for boat parts that spend a lot of time underwater so I should be safe) and to highlight the beautiful wood that Sandman picked out.
With most of the parts in one place, the nosecone varnished and the motor mount mostly assembled, it looked like this
