NEW 7075 Aluminum U-Bolts - beta testers wanted

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Landru

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I have never really liked the use of eye-bolts in rocketry as most off the shelf hardware is extremely bulky with no concern for weight.

These are designed to remedy a lot of those issues.

Machined from 7075 Aluminum, they have a tensile strength comparable to steel, but at a fraction of the weight. (Only 2.33g!) They are also only 0.25" tall.

I've run these through FEA, and they look to have a max load of around 700lbs before deforming. A welded eye-bolt is 800lb for reference.

The main through hole is sized for 1/4-20 rod/nut, and the secondary mount point is for a #6-32 screw/bolt.

Since these are not a closed loop like an eye-bolt, they can be attached directly to a sewn Kevlar loop and also eliminate a quick link.

I have an initial run I would like to send out to volunteers for test flights. Shoot me a PM if you are interested.

Please keep in mind this is beta hardware, and while I have done preliminary analysis to ensure their performance, you should take additional precautions and an extra dose of common sense with their implementation.


Any other comments/questions/suggestions are welcome.




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JohnCoker

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Very clever idea. I've used SS webbing guides as something of an equivalent, but they're a bit long and thus limited to larger diameters.

Your idea is great and I hope to see it turn into a product.
 

cwbullet

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AHansom

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Very nice. Projects like that are going to put me over the edge on getting a mini CNC mill. Up until now I have always used the U-bolt from a small cable clamp. Yours is much sleeker...

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kyle

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I'm curious as to why the two different sized mounting holes. And am willing to give it a go if you still need testers. After not launching anything for years after moving from the middle of nowhere to the middle of everywhere I've overcome my stage fright and am setting myself up for my level 1 and 2 flights in the next couple of months, hopefully.
 

Lloyd Leichentritt

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I just went with two Eye-bolts over the U-Bolts for my LOC BBX. I added a 5/8″ Tubular Nylon Y-harness from LOC Precision to the Eye-Bolts. It's hard to tell from the photo is the loops will fit.
 

Landru

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I'm curious as to why the two different sized mounting holes. And am willing to give it a go if you still need testers. After not launching anything for years after moving from the middle of nowhere to the middle of everywhere I've overcome my stage fright and am setting myself up for my level 1 and 2 flights in the next couple of months, hopefully.
Didn't seem to need a 2nd 1/4-20 for strength, and it made things bulkier. Mostly needed to 'complete the loop' and prevent the U-bolt from unscrewing. I may change my mind if testing indicates I need a beefier 2nd.

I just went with two Eye-bolts over the U-Bolts for my LOC BBX. I added a 5/8″ Tubular Nylon Y-harness from LOC Precision to the Eye-Bolts. It's hard to tell from the photo is the loops will fit.
These won't fit. This is for ~1/4" Kevlar and smaller. This is for ~3" and lighter 4" rockets. If these go well I will offer bigger versions.
 
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Conway Stevens

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Definitely would be interested in these Andrew. I have some 3 inch minimum diameter stuff this would work great for. Would love to try them out.
 

manixFan

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I also would love a couple to test out. I fly a lot of MD rockets and have been doing something similar with fender washers, but your solution is much more elegant and I'm sure much more robust. I'll send you a PM as well. I use kevlar with fingertrap loops so these would be perfect.

Thank you,


Tony
 

Hybrid33

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Finally completed my first beta test
54mm min Diameter carbon airframe Max Q fin can propelled by Loki M1378 to 35,242 ft using your parts on the nose cone coupler and AV bay lid, in other words on both ends of recovery gear !!!Thank you for great strength and low weight !!!
 

cwbullet

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Finished beta testing this weeked. This is the perfect option for dual deployment in a minimum diameter!!!!
 

Hybrid33

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First and foremost Thank You Thank You for this product !!! After flying the pair you so kindly shipped to me at your expense at Airfest, main at apogee, not planned that way !!!When will these be available for purchase ?
 

Landru

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I'll push to get them up in the next week.

What did you all end up using for bolts? The ones I sent, or something else? Pictures please!
 

Hybrid33

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OK here they are
I used 8-32 X 1" SHCS because I the 1/4" thick AV bay lid and nose cone coupler lid required
a longer bolt to engage the nylon in the nylock nut .
If you need more pics let me know
 

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