Resurrecting my V2

[Landshark]

All...

This past weekend (after visiting my parents on Mother's Day), I found my old Estes V2 that I built around 12 years ago. It's in pretty good shape and I'd love to fly it again, however one of the fins was cracked (fixed that) and I immediately noticed a shock cord problem.

I think the thing had been sitting so long that the cord got old / brittle and snapped off in my hands. If I'm not mistaken, that cord was tied to/through the engine mount way down in the tube.

What can I do to repair this after I locate some more shock cord? I'm assuming the normal type of glue-on body tube attachment wouldn't be sufficient for this one. Any ideas or advice?

I'll see if I can post some pics later of the beast...

 

[Pem Tech]

What can I do to repair this after I locate some more shock cord? I'm assuming the normal type of glue-on body tube attachment wouldn't be sufficient for this one. Any ideas or advice?

I'll see if I can post some pics later of the beast...

Shweet find....
Wish some of my old builds would resurface.
You might not want to sell the glue on body tube method short. When first getting back into rocketry I was shocked to see that LOC used a bit of cord glued to the inside of the tube to attach the shockcord. Well, now we use KEVLAR yarn, in the same manner, in a couple of our MPR kits. Essentially, you tape a loop of 300lb KEVLAR inside the tube and shmear the tape and the tails of the KEVLAR (not the loop) with epoxy. Once cured, attach your shockcord through the loop and go...
All Bucky Jones kits use this method as well as our M2 - Mars Challenger and no failures have been reported. The Prototype M2 has been flying on the original attachment for about five years now, with no sign of giving up the ghost.
Just my :2:

Now, post some pics so the rest of us and admire your beast.
:cyclops:

 

[Landshark]

Thanks, PemTech for your suggestions. I'm going to have to look around for a source for the kevlar cord and see what I can work out. What type of epoxy would be best for the task?

And... here's some pics of the V2. I built this one while I was in grad school about 12 years ago (the first wave of "born again rocketry" although the kit was probably a good 10 years old at that point. Not sure I got the camo right and it's a bit dinged up from being in storage, but it's one of my favorite rockets...

and a shot of the nose cone separated from the body tube plus the original parachute. Not sure why I didn't have the chute on a swivel / quick detach.

 

[Pem Tech]

Thanks, PemTech for your suggestions. I'm going to have to look around for a source for the kevlar cord and see what I can work out. What type of epoxy would be best for the task?

PM me your address and I'll send you a couple of KEVLAR types at no charge.

Don't know what epoxy would be "best" but we use West System 105 resin and 205 hardener. I am sure you will get a dozen or so opinions on builder's favorite epoxy, search the forum and do some research. In the end you will have to just pick one that fits your needs and budget and go for it.

 

[jdud]

Great find-V2's are cool. I've fixed several rockets just the way PemTech is describing...works great! If you have a Hobby Lobby or a local hobby shop in your area, they likely carry small epoxy kits with small bottles of hardener and resin...or you could just pop in wally world and get one of the syringe-type epoxy kits. I like to use the 30 min epoxy because it can soak into the materials before it sets.

 

[GlennW]

All...

What can I do to repair this after I locate some more shock cord? I'm assuming the normal type of glue-on body tube attachment wouldn't be sufficient for this one. Any ideas or advice?

Landshark, the classic Estes trifold mount method should work fine. I have a Big Daddy that had the original attachment on the upper centering ring, when that gave way I just made a trifold mount to the side of the BT and it's worked well.

Having said that, the other suggestions are certainly worth considering.

Glenn

 

[mjennings]

Yeah I need to repair mine as well I had a NC Separation event the last time I flew it, lost the camo'ed NC in a very overgrown area, Fortunatly I found a Canadian Arrow kit to replace the NC. Tri-Fold or Layne's method should work fine. Just make sure you give it a lot longer cord that Estes original used. I'd go for at least a 15 min epoxy with 30min+ being preferable, but I have an aversion to the quick cure stuff because of who I learned from, and I can never seem to work quite fast enough with out making a huge mess.

 

[TheRocketNerd]

for this type of repair, any type of epoxy will suffice, though some slower set wouldn't be a bad idea. Just some house-brand epoxy at the hobby store or some syringe type epoxy as was mentioned will do the deed just dandy. I'd go for at least 6' of 1/4" elastic. And mount the shock cord loop so that it is entirely below the lip of the body tube...the smaller diameter kevlar is more prone to zipper than the flat elastic in the event of an anomalous ejection charge.

 

[luke strawwalker]

I've been using kevlar in an Estes trifold type shock cord mount and that seems to work well. I also put it all together with yellow glue, clamp it up with hemostats, let it dry, then glue the mount into the body tube with yellow glue. No problems.

Later! OL JR

 

[RoyAtl]

Go ahead a use an Estes tri-fold mount on that. It'll do just fine.

The old LOC method mentioned works great too, and you don't need kevlar. just thick cotton twine should do for the V2.

 

[Landshark]

Ok... this may be a dumb question, but does the shock cord actually need to be elastic? Seems like by putting 6 feet of kevlar / cotton cord, you'd be taking out a lot of the initial "shock" when the ejection occurs and the stretch wouldn't be needed so much.

Also...on the subject of elastic, where's a good source for the 1/4" kind? Fabric store maybe? That may be a route I could go on some of the older smaller body tube designs I have...

 

[RoyAtl]

Quite true. Harry Stine determined years ago that most small rockets just need a length of cotton twine. And most competition rockets use just a length of thin kevlar. Elastic is just the continuation of a tradition from the early days of model rocketry, when it was customary to use model airplane rubber, because that's what Orville Carlisle used on his first model rocket. Harry then copied him, and Vern Estes copied Harry, and so on.

 

[Pem Tech]

Ok... this may be a dumb question, but does the shock cord actually need to be elastic? Seems like by putting 6 feet of kevlar / cotton cord, you'd be taking out a lot of the initial "shock" when the ejection occurs and the stretch wouldn't be needed so much.

Exactly our philosophy.....
Our LPR kits have NO elastic in their recovery system, instead they have 60"of 300 lb kevlar twine. No snap-back and lasts pert' near forever.

 

[TheAviator]

If you do mount Kevlar in a tri-fold mount, tie some knots in the cord that will be inside the folds. This will help to keep it from pulling out later. If you go with an all Kevlar cord, a good rule of thumb is to keep it at least 2.5x longer than the rocket itself. Generally, I do 3x for good measure.

 

[Handeman]

What I've been using is the cloth ribbon from the sewing section in Walmart. It's about 3/16" wide and is very strong since it is cloth. IIRC, it cost about $0.49 for a 6 yard spool. It also comes in a huge variety of colors so you can color coordinate your shock cord with your rocket.

 

[Landshark]

Quick update... Big thanks to Pem Tech who sent me a nice length of kevlar braided cord and a smaller diameter kevlar line (shroud line, I think) to fix the V2. The piece was just about perfect.. just about 2.5 times the length of the rocket.

I decided to use the classic tri-fold design mount, so I cut a suitable piece of paper, knotted the cord in one spot (center fold) and stuck it together with yellow glue.

Next, I carefully sanded off the ejection charge residue on the inside of the V2's body tube to promote glue adhesion. I chose yellow glue once again and installed the mount around 2-3" below the top of the tube. I was concerned about getting the mount too close to the engine mount / hot ejection charge or else I would have put it lower...

I let it dry overnight and it turned out to be a very solid mount. Itching to get this one in the air again after 12 years or so of rest, my son and I took it out to a large local part and loaded it up with a D-12-5. It was a clear day and a great flight...

Here's a shot of the liftoff (Kudos to Josh K who set up his nice digicamera tripod near the pad and took a video of the launch. This is one of my favorite frames he captured for me)

The rocket performed perfectly...strong boost, great altitude and the recovery was flawless with an 18" parachute. My son was able to recover the V2 about 150 feet from the pad in great condition (almost caught it). Thanks again to everyone especially Pem Tech for helping get this old bird back in the air!

 

[Phred]

Great resto job! V2s are my favoirite rocket of all time.

 

[Pem Tech]

You are welcome....
Just glad you could get your bird flying again.

 

[TheAviator]

Quite welcome. That's a beautiful bird you have there and a great liftoff pic. (You know we here at TRF are suckers for liftoff pics. )