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I considered posting this in the Recovery forum but since this is more of a build/structural question, I'm putting it here.
I'm making my way through my Adventurer 2.2 build (last two internal fillets just injected) and now am contemplating how I'll attach the 54mm Giant Leap aluminum hardpoint anchor that I'll be using to hang my drogue laundry from. Typically this is epoxied into the motor tube, but since I need way more room in the fin can, I got a larger size that I'll attach directly to the body tube just above where my longest motor casing ends.
I've chosen this option because I want to have a removable anchor point for my recovery harness and allow for the option of motor eject or motor eject backup.
My first thought was to drill and tap three holes and attach with some machine screws - ideally countersunk for a streamlined profile. Only problem with this is it's thin-wall FG and the anchor is just as thin. We're looking at 1mm total (.47mm for the body tube and .53mm for the wall of the anchor). Is there even enough material to tap threads into?
I wish I had some extra body tube to practice/test this on...
Another option would be to use self-tapping or sheet metal screws and call it a day.
Considered removable rivets, but the only option I could find is the good old vinyl ones we all use. My concern here is that the heat from the ejection charge would weaken/melt them. If that's not an issue, this would probably be my best option.
In Wayco's Mongoose 54 build thread he uses "pem nuts" to attach his motor retainer - more or less what I'm doing - but I'm not sure if the anchor walls in mine will be thick enough to hold one? https://www.rocketryforum.com/showthread.php?130487-Wayco-s-RW-Mongoose-54-build
A similar option would be to drill my screw holes and JB Weld some weld nuts inside the anchor. Ideally I'd have to bend the flange on the nut to match the curve of the anchor (any ideas on how do to that?) and with a pan or truss headed screw outside there should be plenty of mechanical hold.
Currently my favored option is the simplicity of machine screws, but I would prefer the ease (and look) of plastic rivets if they would hold up to the ejection heat and are sufficiently strong to anchor my recovery gear.
Otherwise maybe weld nuts would be the way to go.
Here's a picture of the anchor with the switch band around it so you can get a visual of the thickness.
I'm making my way through my Adventurer 2.2 build (last two internal fillets just injected) and now am contemplating how I'll attach the 54mm Giant Leap aluminum hardpoint anchor that I'll be using to hang my drogue laundry from. Typically this is epoxied into the motor tube, but since I need way more room in the fin can, I got a larger size that I'll attach directly to the body tube just above where my longest motor casing ends.
I've chosen this option because I want to have a removable anchor point for my recovery harness and allow for the option of motor eject or motor eject backup.
My first thought was to drill and tap three holes and attach with some machine screws - ideally countersunk for a streamlined profile. Only problem with this is it's thin-wall FG and the anchor is just as thin. We're looking at 1mm total (.47mm for the body tube and .53mm for the wall of the anchor). Is there even enough material to tap threads into?
I wish I had some extra body tube to practice/test this on...
Another option would be to use self-tapping or sheet metal screws and call it a day.
Considered removable rivets, but the only option I could find is the good old vinyl ones we all use. My concern here is that the heat from the ejection charge would weaken/melt them. If that's not an issue, this would probably be my best option.
In Wayco's Mongoose 54 build thread he uses "pem nuts" to attach his motor retainer - more or less what I'm doing - but I'm not sure if the anchor walls in mine will be thick enough to hold one? https://www.rocketryforum.com/showthread.php?130487-Wayco-s-RW-Mongoose-54-build
A similar option would be to drill my screw holes and JB Weld some weld nuts inside the anchor. Ideally I'd have to bend the flange on the nut to match the curve of the anchor (any ideas on how do to that?) and with a pan or truss headed screw outside there should be plenty of mechanical hold.
Currently my favored option is the simplicity of machine screws, but I would prefer the ease (and look) of plastic rivets if they would hold up to the ejection heat and are sufficiently strong to anchor my recovery gear.
Otherwise maybe weld nuts would be the way to go.
Here's a picture of the anchor with the switch band around it so you can get a visual of the thickness.
