PRE-ORDER for Rocketry Nut Recovery Anchors

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ptrocketry

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Prairie Twister Rocketry is excited to announce the pre-order sale for their new innovative new recovery anchor - the Rocketry Nut.
The rocketry nut combines the strength of an eyenut with the simplicity of a quick link. It is easy to install using a 9/16" wrench or socket, then secure your recovery harness with the clevis pin. For more information please see HERE

The first lot is being manufactured currently and our pre-order will go from now until July 31st. They will then be shipped when we receive them - you pay when we ship them.

Pre-order prices will be:
1 for $7.00
2 for $13.00
4 for $24.00

Please use the form on our website to place your order!

PRE-ORDER FORM

Edward
 
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Here is a picture from a previous thread - it is not screwed onto an stud, but you just screw it down to your threaded anchor point.

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Edward
 
Thanks. I have never seen this done. I must have missed the thread.
 
This is an adaptation of something that a long time very experience flier with my club did. I added the clevis pin and cotter pin and made it out of hex stock. I use them for up to 5.5" rockets - the heaviest was 50 pounds.

If there is interest in different threads I can certainly do that as well.

Edward
 
What size recovery harness would you be looking at? I have used some 1/2" hex stock with smaller ones but the standard is 1/4-20.

Edward
 
Am I being thick or something as I don't see how this works.

Would it not spin undone during decent?

The shock chord has the pin through it?

More photos I think to explain it
 
Here is a picture from a previous thread - it is not screwed onto an stud, but you just screw it down to your threaded anchor point.

attachment.php


Edward

Does the harness have a loop in it that the pin goes through? If so I think I can see it:) What size harness will fit into the nut?
 
The harness has either a sewn loop or a tied loop. For tied loops I prefer the bowline knot. The loop goes in, the steel clevis pin goes through the loop and is secured with a cotter pin on the other side. This works with recovery harness up to 3/8" diameter. I have designed some that use a smaller hex, but this size is perfect for just about all those mid-HPR (H-K) rocket sizes.

To prevent unscrewing you can use a lock washer. I have been flying with the local club for nearly 15 years and I have never seen or heard of an instance of an eyenut or one of these unscrewing. That does not it mean it cannot happen, but I think it is rare. With proper avionics bay design and adequate tightening of the anchor (either these or an eyenut) you can prevent them unscrewing.

Edward
 
Here are some pictures of the anchor attached to a 98mm avionics bay.

This one is compared to what used to be my go to choice for anchoring - a 1/4-20 eyenut. You can see that the Rocketry Nut is more compact.
photo 2.jpg

Installed ready to accept the recovery harness.
photo 4.jpg

Showing the looped recovery harness. This one is sewn, tied works as well.
photo 3.jpg

Final installation of the Rocketry Nut and recovery harness - ready to fly!
photo 7.jpg


Edward
 
Okay, now I get it. I was thinking whoopee before, but now I see where you are going with this. I like the compactness as well. Do you have any numbers on the strength of this setup compared to equivalent eye or U-bolts?
 
I have flown this anchor for the past 8 years and it has never come loose. I do tighten with a wrench and keep it under tension. Most rockets are in the 20-35 pound range, one was fifty pounds. The first iteration had a small 6-32 set screw at the base to prevent unscrewing. This served to muck up perfectly good threads and make it harder to install each time.

As for strength when I first wanted to see how strong it was I sent three over to Doc at Rocket Materials. He snapped all the kevlar cord he was using to pull on it with. We never came up with a good way to try to get these to fail.

Edward
 
Thank for showing us. Dam that's small. Might have to get some offered. Hopefully Onebadhawk can do me a nice recovery line to match. Tied knot wouldn't looks right.

A lock washer would do it your right.
 
All - I'm going to extend the pre-order, the shop that I'm currently working with had a bar feeder go down and I'm low on the totem pole for getting these made. I'm hoping to have them done in a couple weeks. If I can't, I'll start making the pre-order quantities on a manual lathe and fulfilling them that way. I'll keep you updated.

Edward
 
This works great for motors with tapped forward closures. A simple allen socket set screw is ideal. You tighten the set screw down with the allen, then thread this on the stud and tighten with a wrench.

Edward
 
I just heard from the shop today that they can hold September 4th as the date I'll get them. This happens when you are low(ish) quantity in a shop that does very big runs. I'll be sending them out as soon as I get them in my hands.

Edward
 
Are you still on schedule to ship the pre-orders on or around the 4th?

Also, in your trials, did you use a lockwasher to keep the nut in place? From the pictures it looks like there is only a fender washer next to the bulkhead.
 
I will have them delivered to me the 3rd or 4th, then send out invoices and start shipping then.

Trials makes it sound like it was only a few flights, these have been flown for 8 years with every rocket I've flown. I've never had them unscrew. I tighten them with a wrench on a fender washer and under the fender washer there is a rubber fender washer to seal the two 1/8" holes the e-matches come through. You can definitely add a lockwasher underneath it.

Edward
 
Edward is top notch, he is letting me use his rocketry nuts for next weekend at Airfest. Once again thanks.

WP_20150830_16_42_03_Pro.jpg
 
All,

Is there any interest in my offering allen set studs and lock washers with these? I'd offer them in a a couple of common lengths that would work with forward closures? The cost would be very close to what I pay for them but offer them so it is convenient.

Edward
 
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