Hi There Folks....
I obtained one of the Cherokee G kits offered on TRF a while back and at last I got around to building it. Working on the electronics bay and so on, I started drilling holes... today got the ones for the rivets done... a genuine p.i.t.a. to do it cleanly.... frankly, now that I have an altimeter for the e-bay, I'm amazed how many holes I'm going to have to drill... never had to use a drill on a rocket so much. But that's holes not fillets....
The author of the kit recommended doing the fillets using microballoons (the preference was for west systems 410 which is $17 for 2 fl. oz.) I've done epoxy fillets on a couple of estes builder's kits (the Ventris and the Sahara). I didn't think I'd ever crack a fillet on a ttw fin that was made out of epoxy, but the ventris got a hairline crack on the fillet after a hard landing... generally I think I do a reasonable fillet job on most of the kits but with basic low power rockets (my Goblin clone as a case and point), a hard landing causes the tube to peel up or delaminate... At least with a ttw fin, a hard landing will tend to NOT have the tube outer layers peel off!
So this leads me to the following question... for a big MPR-HPR, does adding microballons add any advantage strength-wise as far as the fillet is concerned? I can see how it will make the fillet resistant to running if your rocket isn't level, but what is the thinking in terms of added strength? I've never used this stuff before so I picked up a 2 fl oz container of Top Flite MBs (MUCH less expensive than WS's)... and if it makes these fillets resist fractures on hard landings, I'll be very pleased...
Let me know what y'all think!
I obtained one of the Cherokee G kits offered on TRF a while back and at last I got around to building it. Working on the electronics bay and so on, I started drilling holes... today got the ones for the rivets done... a genuine p.i.t.a. to do it cleanly.... frankly, now that I have an altimeter for the e-bay, I'm amazed how many holes I'm going to have to drill... never had to use a drill on a rocket so much. But that's holes not fillets....
The author of the kit recommended doing the fillets using microballoons (the preference was for west systems 410 which is $17 for 2 fl. oz.) I've done epoxy fillets on a couple of estes builder's kits (the Ventris and the Sahara). I didn't think I'd ever crack a fillet on a ttw fin that was made out of epoxy, but the ventris got a hairline crack on the fillet after a hard landing... generally I think I do a reasonable fillet job on most of the kits but with basic low power rockets (my Goblin clone as a case and point), a hard landing causes the tube to peel up or delaminate... At least with a ttw fin, a hard landing will tend to NOT have the tube outer layers peel off!
So this leads me to the following question... for a big MPR-HPR, does adding microballons add any advantage strength-wise as far as the fillet is concerned? I can see how it will make the fillet resistant to running if your rocket isn't level, but what is the thinking in terms of added strength? I've never used this stuff before so I picked up a 2 fl oz container of Top Flite MBs (MUCH less expensive than WS's)... and if it makes these fillets resist fractures on hard landings, I'll be very pleased...
Let me know what y'all think!