Tethys kit arrived

hey peoples

My tethys kit has arrived along with the payload bay for the electronics i ve just started construction on the kwik switch motor mount hope to get some construstion pics soon
plus i don't wont to do the fins yet becuase im unsure about the glassing process could you please give me some tips or suggestions that may help in the process

thank you

Well, with glassing, I strongly reccommend NOT glassing the outside fillets as this makes finishing a pain. I would use glass on the to the motor mount fillets. I have heard speading it out, or rolling it and stciking it into the fillet. I know this is not as easy, but if a good rocket is a plus to you, finishing over the glass can be hard. I only glassed the outside fillets on one rocket, and it's a woody now!

I find finishing 'glassed fillets to be rather easy. It just takes time and a little practice. First off, you need to get some high quality finishing products-- SuperFil and Smooth Prime. These are available from Dave Triano at Shadow Composites (https://www.shadowaero.com) and from Aircraft Spruce (https://www.aircraftspruce.com). Smooth Prime is a high-build primer that fills pinholes very quickly. It sands off like butter too. You can get very high quality, smooth base coats with this stuff. SuperFil is the rocketeer's equivalent of Bondo. It is epoxy based, so it sticks better to your projects, and it sands very easily. I don't have a share in PolyFiber or anything, I just love their products.

To finish my fillets, I simply spread SuperFil over the edges of the glass to get them nice and smooth, sand once, then Smooth Prime until the weave is filled. Then I base coat with white and do a guide coat with black spray paint. I sand most of this off, and fill in the low spots with either more SuperFil or more Smooth Prime. I repeat this process until all the black sands evenly off. Then I prime and paint as usual. With a little time and work, my rockets are pretty now (and to think, my first adventure painting a rocket ended with wiping the entire thing off with paint thinner while the paint was still wet, and then getting little fuzzies in the paint, and then... oh my.)

HTH.

thanks guys that will come in real handy funnly enough just after you posted these i was at that stage cheers


ill get some pics up soon for all to see

hey peoples m,y tethys kit is complete i just havn't got round to posting the pics anyways i want to launch it on a J415 in some poin in time to 6900ft any ways it will reach 0.91 mach pml recommends .85 but the extra speed is only 47.8 miles and hour about 70 ft second i know about the high presure build up when you reach 0.85 but i was wondering if the turbulance by just that .06 xtra speed would destroy the QT airframe

Matt,

I don't think the integrity of the QT at these speeds is the main issue. You really have to be concerned about the bonding between the QT and G-10. Neither of these materials "soak up" epoxy like wood and cardboard and therefore the mechanical bond is much less likely to be able to withstand the stresses at mach. If the fins come loose, the airframe is doomed.

If you really sanded all the surfaces well and are confident in your construction techniques, then it is do-able. I have seen QT rockets withstand mach. I have also seen them disintegrate, as well.

You can always ease yourself up to that J415. The Tethys flies GREAT on a J275.

--Lance.

thanks man i ve been trying to get some 70 g glass at the moment i ve only glassed it with 20g stuff which is way to light so when i get some of that ill look further in to it

thanx

it flew and it flew bloody well, me and matt preped and flew it on a I284w and it was almost perfect flight apart from the payload section seperated at 300' and came in updamaged
here is a pic of the prep on the launch pad

matt

here is a pic of it in mid flight

matt