Warren B. Musselman

Ed – I like the double centering ring approach for the booster retention u-bolts, but do you think it is stronger than just stacking a pair of rings together? Surface area of the glue joint would be the same and…   Read more»

Look for a detailed article in the next 24 hours regarding my L3, vacuum-bagging and recovery systems in the Composite Construction forum.Warren

I’ll stand by my statement – don’t glue in webbing as your shock cord anchor – regardless of the material. In a 4″ bird with a 54mm motor mount you can easily use a forged eyebolt and washer or a…   Read more»

I’m in Longmont most days, be glad to shoot the shit – no need for the beer or bourbon.

For another point to add, I have epoxied 1/4-20 eyebolts into Pro-38 ejection wells after removing the ejection charge. Rough up the inside of the plastic well with 80 grit sandpaper and they hold very well. I’m not sure you…   Read more»

Do it all the time on rockets considerably heavier than you can get with a 4″ bird. The UprOar project (8″ O-powered) used a zipperless design with a 1/2″ U-bolt through the zipperless bulkhead.

I agree with John on this. ANY fabric webbing epoxied to the motor mount will eventually fail – usually sooner rather than later. At that point, the rocket becomes unflyable. I have a PML Io that I’ve been flying since…   Read more»

I was going to say, we need to put a Raven and Telemetrum in a dark box and give them some privacy… who knows what might happen.W

I talked to a buddy today who works at Sparkfun about it and it is possible to sub other parts with some trace mods. I haven’t gotten specific with him, just mentioned a requirement for 50G-100G in the Z axis…   Read more»

I saw this online this morning and have been thinking about it ever since. The $90 pricetag is a bit steep for me now, but I have 4 Arduino’s on the bench – 2 standard units, a Pro and a…   Read more»

I’ve seen and played with a venturi vacuum generator, but didn’t think it could pull as much vacuum as I wanted. I ended up buying a surplus vacuum pump from Aircraft Composites I think it was. Cost $130 or so…   Read more»

When I was a boy scout and ham, I got to take NASA’s space soldering school at RCA’s David Sarnoff Research Center in Princeton, NJ. I still have the training book somewhere. All kinds of stuff like little kinks in…   Read more»

Definitely go 98mm – you have more options. If you want to fly a 75mm, you can always use an adapter. My L3 was built with a 98 mount and I can fly anything from a 54mm L up through…   Read more»

I understand entirely Tony – I’m much the same way. I also blatantly steal good ideas where I find them and after reading your posts on this thread, I find that a bunch of idea I thought I stole from…   Read more»

I’d be careful about welding to most motor cases unless you have the capability to re-heat treat the case after the welding. The ideal, from what I know, would be to make a case specifically for the purpose. Machine the…   Read more»

If you chemically thin pretty much any epoxy more than 10%, you significantly reduce the cross-linking in the polymer during cure and thereby reduce the strength of the epoxy. Some manufacturers will even tell you that it reduces strength more…   Read more»

Nice video Tony. Now if you only vacuum-bagged, you could get 6oz fabric to lay down that tight and have a much stronger layup.Edit:- I’m curious about the epoxy too – what brand? Post-cure?

Threaded forward closure in all cases. Alternative for motor cases without a threaded hole would be a bulkhead on a T-nut plus tape to prevent rear-ward loss of the motor case.CTI doesn’t have that on 38mm cases, but those I…   Read more»

I’m a firm believer in zipperless booster designs with a threaded rod going through the zipperless bulkhead to an eye-nut on MD projects. Problem comes when you’re talking about single-use motors.

Thanks Tony,That’s kinda what I envisioned except for the zipperless nosecone/forward airframe thing. I figured you’d have to attach the shock cord at the tip and put the charge in forward of the laundry in order to deploy properly. The…   Read more»