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LOC PRECISION LOC IV

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crazyed

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Finally after all these years I get to build one. Im not real good at build threads and I tend to use old school techniques. Sometimes making adjustments to the instructions as I go. I will use Items I have around the house to achieve my goals.I will do my best on this build to get a nice finish( looking for no spirals in the airframe).

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crazyed

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I will use this method of harness attachment to the MMT. The tape is wrapped around the screws I put thru the MMT so I can add cooling mesh from the back end and not have it blow thru. There is epoxy around the tube and screws also.

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crazyed

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Building for F- G- H and I motors. No dual deploy. Max altitude 3,000ft.
 

markkoelsch

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Does your version have the 29mm mount of the 38mm?

Does your version have fins tabs through the wall or to the motor mount?

I would ditch the mesh and just use nomex.
 

qquake2k

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The LOC IV was one of my first high power rockets. It's a great flier!

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crazyed

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Does your version have the 29mm mount of the 38mm?

Does your version have fins tabs through the wall or to the motor mount?

I would ditch the mesh and just use nomex.
38mm and to the motor tube.
 

crazyed

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A good rough surface for the fin attachment and another view of the forward ring

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crazyed

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As soon as the ring epoxy sets up, it will get a test. The kit would go together very quick but I like to take a little time with it. I will test fit the mount and then use some more filler on the airframe and sand. I really want a good finish on the frame so I'll spend a bit more time on that. Fins get filled and sanded but not much on the aerodynamic shaping.
 

crazyed

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Top view, still more epoxy to be added both ends.

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qquake2k

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That's a pretty thin Kevlar cord. I wouldn't worry about strength, but I might be concerned about zippers.
 

ascastil

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Does epoxy not weaken kevlar? Id like to use that technique if it doesnt.
 

dixontj93060

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Does epoxy not weaken kevlar? Id like to use that technique if it doesnt.
Probably referring to Kevlar's susceptibility to friction/fraying which would happen if the epoxy is at a junction where the cord had a lot of movement. Not sure about this build, but attaching the cord with epoxy a ways down on the motor mount, then allowing for another cinch point at the CR (protect the cord at this junction with Vaseline) helps protect from any fraying where the epoxy bond is located.
 

Steve Shannon

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Does epoxy not weaken kevlar? Id like to use that technique if it doesnt.
Chemically no, Kevlar and epoxy are compatible. However, Kevlar is susceptible to sudden failure as a result of concentrated stress and its inability to stretch, so if you have epoxy wick into your Kevlar shock cord you will end up with a stiff section. At the edge of that stiff section the stresses may be concentrated leading to failure. That's not a weakness so much as just poor construction.
Kevlar has its place, but I prefer tubular nylon for those portions of shock cord that are not directly exposed to ejection charges. The only shock cord I've ever broken was Kevlar.


Steve Shannon
 

mad4hws

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Chemically no, Kevlar and epoxy are compatible. However, Kevlar is susceptible to sudden failure as a result of concentrated stress and its inability to stretch, so if you have epoxy wick into your Kevlar shock cord you will end up with a stiff section. At the edge of that stiff section the stresses may be concentrated leading to failure. That's not a weakness so much as just poor construction.
Kevlar has its place, but I prefer tubular nylon for those portions of shock cord that are not directly exposed to ejection charges. The only shock cord I've ever broken was Kevlar.


Steve Shannon
one thing I do to prevent this is to put some heat shrink tubing around the kevlar where it comes in contact with epoxy/CA glue. This prevents the adhesive from penetrating the fibers of the Kevlar and creating a stress point. I can't take credit for this technique - I stole from somebody - not sure who. But, it works remarkably well.
 

The_Lone_Beagle

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I meant to say, not sure if you knew, John Coker has a (as usual) great video on YouTube showing his build of a LOC IV.

[video=youtube;Xtr3758PvzA]https://www.youtube.com/watch?v=Xtr3758PvzA[/video]
 

4kids49

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Here goes centering rings epoxy
The epoxy on this part of the kevlar might be fine, as the centering ring might help absorb some of the stress on the kevlar shock cord. I would be concerned about getting epoxy on the kevlar on the other side of the centering ring when it is epoxied in place. An inch or so of epoxy on that kevlar will generate stresses as per comments from Steve below.

Chemically no, Kevlar and epoxy are compatible. However, Kevlar is susceptible to sudden failure as a result of concentrated stress and its inability to stretch, so if you have epoxy wick into your Kevlar shock cord you will end up with a stiff section. At the edge of that stiff section the stresses may be concentrated leading to failure. That's not a weakness so much as just poor construction.
Kevlar has its place, but I prefer tubular nylon for those portions of shock cord that are not directly exposed to ejection charges. The only shock cord I've ever broken was Kevlar.


Steve Shannon
You are exactly correct Steve. Epoxy on kevlar can cause concentration of stress. If done properly, as in using epoxy to glue down harness straps to motor mounts, as routinely done by CJ and Wildman, works well. Epoxy coming up a kevlar cord can break. Don't ask me how I know that! lol I wish someone had told me that before I did it.
 

crazyed

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That's a pretty thin Kevlar cord. I wouldn't worry about strength, but I might be concerned about zippers.
What Im using here is nylon paracord.
 
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crazyed

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I meant to say, not sure if you knew, John Coker has a (as usual) great video on YouTube showing his build of a LOC IV.

[video=youtube;Xtr3758PvzA]https://www.youtube.com/watch?v=Xtr3758PvzA[/video]
He has some very good info and build threads.
 

4kids49

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What Im using here is nylon paracord.
Crazyed, I am sure that your cord will be fine. I would protect from heat as others have mentioned. That cord might have a finite lifetime though, no matter how well that you build it. That is the problem that I have had with nearly all of the numerous Estes rockets that I built with my kids. Once the cord is shot, then you have to make some modifications to incorporate a new cord and the rocket is already built. That is not always easy. You might consider installing a U-bolt on the top centering ring as an insurance policy. If something happens to your cord, you can always attach something via a quick link. You will really like your LOC-IV. The stock chute on my LOC-IV is too big. The rocket drifts a lot in the air when under chute. It also moves on the ground in a good wind. If you find that happens with yours, you can always change to a smaller chute. Good luck with the rest of your build.
 

qquake2k

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I put an eyebolt in the upper centering ring. Since it's a 4" body, I can easily reach inside and attach the shock cord with a quick link.

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