Ordered some parts for an L1 cert attempt!

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ascastil

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I love the big rockets so its about time to certify. Went out to my club launch Saturday and had 5 successful launches on E and F reloads. The clouds were to low for me to feel comfortable with any G motors. I feel pretty good and comfortable with my reload assembly, chutes all deployed with the new to me shroud lines inside the parachute and not wrapped around, and the Jolly Logic worked flawlessly at 300'. I did have one nose cone come untied from the shock cord though. Im gonna get some more practice flights in with some G motors the next launch and see how Im feeling about the cert attempt.

Anyways, on to the new goodies. Tell me what else I should get if I need to for the build.

AT 38/240 case with aft and forward closure
AT H123-14
38mm retainer
LOC Precision LOC IV!!!
18" chute protector (Ive never used one)
Delay drilling tool
Fix It epoxy clay
220# ball bearing swivel
Large tongue depressors
JB weld
And just because, the large guillotine fin jig. Im tired of eyeballing fins to see if theyre straight. Even with slotted tubes it seems its possible to have one fin at a slight angle.

I have been using Z Poxy 15 minute epoxy on other rockets and Im pretty happy with it. It seems strong, is that gonna be ok for H and I flights?
 

MikeyDSlagle

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My first reload was a G53 in the AT 29/40-120 case, my second was the very motor you are using for my level 1 cert flight. There really is nothing to it. The H148R in that case is pretty nice too. Didn't have camera in hand and the tripod got bumped while recording, but nice long red flame like a laser coming out the back. I only had a handful of flights before I went for Level 1.

I much prefer having an altimeter to control my deployments at apogee. I don't much trust the delays or me drilling them. I now build all my rockets with a nose cone bay to hold a deployment altimeter. Well except for my smaller ones in the works, like the Big Daddy and Mega Mosquito.

I'm not familiar with the epoxy clay or the Zpoxy, but if it has been working for you then go with it. I've gotten to where I tack my fins with 5 minute stuff then do good fillets with some 30 minute epoxy, more precisely US Composites 150 Medium and only recently started using chopped fiberglass in the internals. That rocket is still a work in progress so I will see how it goes.

Go ahead and grab you some tubular kevlar and use it to attach your harness to your motor mount or forward CR. The only LOC kit I have, a Viper IV, has elastic shock cord. I will replace it with 1/2 tubular nylon. Not sure if the LOC IV has the same elastic or not, but you may consider a more robust strap. Lots of folks use 1/4" kevlar, I prefer nylon myself.

May as well go ahead and grab you a coupler or two or an electronics bay in case you want to add an altimeter bay. Oh never mind, you will be using the chute release. Man, I have got to get me one of those!

My level 1 flight on the H123 motor. (see if this works this time) Yeah I know it looks like we are close to trees, that is actually one little clump in the middle of miles of ag fields. My dad used the shade to get the video.

[video=youtube;Fxy1tVzA-Ns]https://www.youtube.com/watch?v=Fxy1tVzA-Ns[/video]

Mikey D
 

ascastil

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Yeah Im not sure how the shock cord is mounted. It says nylon elastic in the description of the kit. What about kevlar cord attached to the motor mount, and then the elastic attached to the top of that. If the elastic gets old, I could change it out by disconnecting it from the top of the kevlar? Id have to be careflu of zippers so I would keep the kevlar shortere than the body tube, then maybe a quick connect for the shock cord and kevlar.
 

ascastil

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Ive just had a thought. Isnt the chute protector tied to the shock cord? Im picturing all these things tied to the shock cord. Chute protector, chute, chute release. Seems like some things have a chance to get tangled up? Ill get some input and suggestions from the guys in my club, just wondering though.
 

grouch

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Awesome kit for a cert but throw that fix it clay in the trash.
 

ascastil

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Hmmm, whys that? I wouldnt have ordered if people on here werent using it.
 

rharshberger

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Fix-it epoxy clay will work for fillets ok, once you get used to making fillets from liquid epoxies like Rocketpoxy or others with various fillers to thicken them (if needed) then you will understand why some dont like clay like products.
 

ascastil

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You say it will work ok, is it strong? I was under the impression it was strong and I really liked the way it looked thick. With my 15 min epoxy, Ive let it stand to thicken, then tried applying it to a fillet on a broken fin I repaired. I liked it, but I dont really have a good technique on applying it I guess. I felt like I was doing a sloppy job. I dont know....


I think Im ready for an L1 attempt, lol. I guess Ill be learning real quick how to make strong fillets and what to use. Do you think itll work for a LOC IV landing on the hard dirt?


Edit: I was going to use the epoxy on the fin attachment to the mm, then the clay on the bt. The clay looked easier for me to use, just thinking.
 
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Nytrunner

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Tubular nylon is great for the cord and stretchier than Kevlar. Plus, a single strip of ductape on the first ~1.5 feet will protect it from the ejection charge. That's my "it works and its cheaper" advice :D.

Does the LOC IV have an eyebolt for cord attachment, or do they say to.epoxy it to the motor mount?

If you tie the chute closer to the nose, and the protector closer to the aft, they should pull apart handily. (12" protectors are fine for rockets of this size)

Have you heard of z-folding for cord management? If not, look it.up, it's awesome!

Does.the LOC IV not.come with a shockcord? That sounds odd to me. I've read that a lot of people do their L1 with it, so you'll likely be fine since you can successfully fly mid-power. I just had to make things difficult on myself and use a 4" Patriot for my L1 (sentimental reasons).
 

ascastil

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I was thinking a combo, kevlar inside the tube, elastic attached to that. I wanted something strong and something stretchy and that I could replace the elastic when it got old.


Kit comes with a elastic shock cord. I guess if that got old, it wouldnt be hard to reach into the tube and pull out the old elastic and tie on a new one, right? Drop the kevlar/elastic combo idea? I picked that idea up from an 18mm rocket I built a while back. Cant remember the company. It had kevlar attached to the mm, and rubber shock cord tied to that.
 
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rharshberger

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You say it will work ok, is it strong? I was under the impression it was strong and I really liked the way it looked thick. With my 15 min epoxy, Ive let it stand to thicken, then tried applying it to a fillet on a broken fin I repaired. I liked it, but I dont really have a good technique on applying it I guess. I felt like I was doing a sloppy job. I dont know....


I think Im ready for an L1 attempt, lol. I guess Ill be learning real quick how to make strong fillets and what to use. Do you think itll work for a LOC IV landing on the hard dirt?


Edit: I was going to use the epoxy on the fin attachment to the mm, then the clay on the bt. The clay looked easier for me to use, just thinking.
I have not used the epoxy clay myself as I generally use laminating epoxy with cabosil and phenolic micro-ballons as thickeners.

The Zpoxy will work fine for your adhesive needs, if used for fillets its some times necessary to use a filler like Bondo Spot and Glazing putty after the primer is applied to pretty up the fillets. The Zpoxy will make a more resilent fillet as it has more flex than the clay (iirc the clay forms a very hard fillet) and the Zpoxy fillets have a somewhat flexible structure.
 

ascastil

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Im starting to think that lpr rocket had kevlar inside the bt because you cant switch it out. If I just use the elastic cord on a 4" rocket, if it gets old, I can just put new cord on it. Maybe Ill scratch that idea. Ive copied that on a few Estes kits. I guess not necessary on a bigger rocket.
 

rharshberger

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For aircraft construction



For arts and crafts with kids
And because people always like to pimp expensive epoxies, I always recommend US Composites 635 laminating or 150 structural epoxies both are less expensive than the Aeropoxy, West and System Three epoxies but work just as well for most of our projects unless its an extreme project.

As for Play-Doh my kids love it.
 

boatgeek

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One of my friends used epoxy clay and took days to sand the fillets to his liking. They were beautiful afterwards, but a lot of work to sand smooth. I'm with Rich on this. I use a laminating epoxy with structural fillers like wood flour or chopped glass for the fillets. If you mix it to a consistency halfway between peanut butter and ketchup, it will stay where you put it and smooth out nicely. A tongue depressor makes a nice filleting tool to give you a smooth surface. A small round file is also a good tool for cleaning up the fillets before final sanding. A sanding filler (microballoons or equivalent) makes a nice smooth coat for final sanding if you have to fill any pinholes.
 

jeff2space

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Im starting to think that lpr rocket had kevlar inside the bt because you cant switch it out. If I just use the elastic cord on a 4" rocket, if it gets old, I can just put new cord on it. Maybe Ill scratch that idea. Ive copied that on a few Estes kits. I guess not necessary on a bigger rocket.
The problem is you'll think there's one more good flight left on the elastic and there won't be. Just use a long 3-4 times rocket length long) of Kevlar as your shock cord.
 

Rocketjunkie

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With LOC kits (wood/cardboard) any epoxy is stronger than the materials bonded. I build completely with 5 min. If the parts fit well, wood glue is lighter and also stronger than the wood or paper body tube.
The nylon cord glued into the body tube works surprisingly well. You can use elastic for rockets under about 2 lb. recovery weight but replace it if you see any sign of scorching. I prefer nylon over Kevlar as the low elasticity of Kevlar greatly increases the loading on the mounting points. If you want the best of both, parallel elastic with nylon or Kevlar with the nylon/Kevlar about 90% the length of the elastic at maximum stretch.
 

kswing

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Good luck with your certification. I've used the clay before and it worked but it was hard to sand and rather brittle once it dried. It is fairly easy to shape before it dries.

As others here have mentioned, epoxy fillets aren't that hard to do and they tend to flex a bit rather than crack. I've had good luck using fairly thick epoxy and a popsicle stick or tongue depressor to shape the fillets. I tape off the area with masking tape or blue tape so that I don't have to worry as much about overruns. I'd also suggest you don't glue on the bottom centering ring until after the fins are installed so that you can more easily do the internal fillets where the fins meet the MMT.
 

rharshberger

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Good luck with your certification. I've used the clay before and it worked but it was hard to sand and rather brittle once it dried. It is fairly easy to shape before it dries.

As others here have mentioned, epoxy fillets aren't that hard to do and they tend to flex a bit rather than crack. I've had good luck using fairly thick epoxy and a popsicle stick or tongue depressor to shape the fillets. I tape off the area with masking tape or blue tape so that I don't have to worry as much about overruns. I'd also suggest you don't glue on the bottom centering ring until after the fins are installed so that you can more easily do the internal fillets where the fins meet the MMT.
Just remember to remove the tape before the epoxy cures since afterwards the tape may be hard to remove, and if its done at the right time the fillet edge will settle a bit instead of leaving a hard line along the taped edge.
 

MikeyDSlagle

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A combo/hybrid recovery harness like you are talking about will work fine. Attach a piece of kevlar to your MMT and quick link nylon, or elastic if you prefer, to that. That is what a lot of folks do. My LOC kit came with a small piece of small nylon and a length of elastic. Not sure what the instructions say on attaching iit, didn't get that far. Shelved the project to work on others.

And yes, there is a lot tied to the shock cord/harness and there is a risk of tangling. That's why folks preach about the importance of packing and folding recovery gear. Just learn your technique and take your time.

You can always lay down zpoxy fillets and then cover them with the clay if you like the way it behaves.

Oh, peel the glassine layer off your MMT in case you haven't heard that before. Better bite for your adhesive.

For your cert flight be ready to answer or show:
Where CP is.
Expected altitude.
How is recovery attached.
I'm sure there are others.

And when building the motor, the delay grain assembly is commonly installed backwards. Make sure you get that part right. Instructions show how to do it so no sweat.

Mikey D
 

ThirstyBarbarian

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If the rocket is 4" diameter, you should be able to easily get your arm all the way down to the forward centering ring. If that's the case, then I would recommend putting an eyebolt in the forward centering ring and using a quick link to attach your shock cord (recovery harness) to the eyebolt. That way it's easily removable for inspection and replacement.

I don't think elastic is all that great once you get up to L1 type rockets. It should be fine for awhile, but will need replacement eventually, and it can cause the airframe and nose cone to collide after ejection due to rebound. Tubular nylon is great --- just use a lot of length, maybe 10 or 15 feet. If you want to use a kevlar leader, that would make the anchor point a bit more heat resistant. Or you could buy one of the very nifty nylon harnesses that have a Kevlar sleeve on the end closest to the ejection charge. Check out OneBadHawk (Teddy) for great recovery harnesses. He's a member here, and a great guy. Check out his website to see the kind of work he does.

Your Kevlar or nomex chute protector probably has a buttonhole in it. You don't usually tie it to the recovery harness. Just run the harness through the buttonhole. I think an 18" protector is a bit big, and you could probably go smaller.

A couple of things to add to the shopping list:

An eyebolt with washers and nut (if you decide to go that way.)

Nylon or Kevlar harness. Plus a length of tubular nylon for the nose cone.

A couple of quick links. One to attach the harness to the eyebolt. And another for the other end of the harness to attach it to the parachute swivel and the length of cord that goes to the nose cone.

Rail buttons or conformal rail guides (unless they are included in the kit). If the kit comes with launch lugs, use rail buttons or rail guides instead. Or you can use both lugs and rail guides by mounting them on different sides of the rocket. Your L1 launch should by off a rail, not a rod. Maybe you can use a rod if you decide to fly the rocket on G motors, but even then, a rail would be better.

And on the day of your cert flight, be sure to have money for another motor. You'll want to do a victory lap flight after you pass!
 

BDB

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All of the advice here is good. The only other thing you need is a copy of OpenRocket or RockSim to run simulations. I'm sure you can download a decent .ork file from RocketReviews.com

+1 for your hybrid harness. I don't do it that way, but it will work fine. You'll just need to replace the elastic after ~10 flights. No big deal.

-1 for epoxy clay. I used some of it to repair a tile in a kitchen floor yesterday. I can't imagine how anyone could pull smooth fillets with it.

+1 for practicing your deployment packing. With a 4" rocket, you won't have any problem fitting all of your recovery gear, as long as you don't just stuff it in there.
 

Cabernut

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Looks like you're all set. Make a checklist beforehand if it helps. It helped me since when it's "go time", it's harder to remember the details.

Also, the only epoxy to steer clear of is the cheap dollar store 5-minute stuff if you find it. Not only does it work more like 2-minute, but it doesn't bond as well as wood glue to cardboard tubes. I once accidentally tested this - I had to remove a glued in coupler to fix a crooked airframe. On one side I used wood glue, and on the other cheapo 5-minute epoxy. The wood glued side was much harder to peel out than the epoxied side. Dollar store materials are not the best, everything else will be fine.
 

ascastil

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Thanks for the advise you guys. Ill practice some clay fillets on another rocket to see if I like it. Ill post more questions if I come up with some, which I probably will. Maybe Ill start a L1 cert build. Everything should be here Wednesday.
 

ascastil

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Oh yeah. Ive decided since I have the chute release, Im going to run the nylon 42" chute off my deceased Gforce instead of the 36" that the kit comes with. Trying to save the fins on landing.
 

Nytrunner

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Sounds like you've got the start of a cert thread right here.

From inception to completion: great story.
 

tHoagland

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I'll weigh in with a dissenting opinion. I've used the epoxy clay on several cardboard rockets (low-mid power) and really enjoyed the experience. The rocket I used for my level 2 certification also used epoxy clay. The trick was to place the clay into position, and then smooth it with a wet finger tip (tool). This resulted in smooth fillets requiring very little sanding and since the epoxy didn't flow, I could do all of the fillets at the same time, making it very fast. I've also used it inside of rockets to create smooth transitions around rail button t-nuts.

I would not use epoxy clay for fillets on a fiberglass rocket but I also would not equate it to Play-Doh. It is just another tool that has its own place and time.
 

grouch

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So my beef with the epoxy clay is that it's a poor substitute for epoxy and filler fillets. It's hard to shape consistently, it's heavy, it's brittle, it's a pain in the butt to sand and it doesn't stick to certain substances all that great. Truth be told on a kit like the LOC 4 all you really need is a tube of wood glue and if you are dead set on fillets, use the trim mold glue. Wood and paper kits prefer wood glue. It's lighter, non toxic and dries quick. It sands easy and is easy to clean up. Save the mixed glue for plastic go fast rockets. Another thing, the LOC 4 will eventually sustain a broken fin past the root. It's way easier to repair if you have small wood glue fillets instead of huge clunky epoxy or epoxy clay fillets. I have build a ton of wood and paper kits and when I started I went the epoxy route too but I later found that wood glue is the superior adhesive for the job and is down right sexy in it's own right.

Lastly, don't try to get it right your first go around. You will make mistakes and learn how to do it better each rocket you build....and there WILL be more. Have fun and enjoy the flight but most of all don't sweat it. An H flight is nothing more than a G with a longer walk.
 

ThirstyBarbarian

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So my beef with the epoxy clay is that it's a poor substitute for epoxy and filler fillets. It's hard to shape consistently, it's heavy, it's brittle, it's a pain in the butt to sand and it doesn't stick to certain substances all that great. Truth be told on a kit like the LOC 4 all you really need is a tube of wood glue and if you are dead set on fillets, use the trim mold glue. Wood and paper kits prefer wood glue. It's lighter, non toxic and dries quick. It sands easy and is easy to clean up. Save the mixed glue for plastic go fast rockets. Another thing, the LOC 4 will eventually sustain a broken fin past the root. It's way easier to repair if you have small wood glue fillets instead of huge clunky epoxy or epoxy clay fillets. I have build a ton of wood and paper kits and when I started I went the epoxy route too but I later found that wood glue is the superior adhesive for the job and is down right sexy in it's own right.

Lastly, don't try to get it right your first go around. You will make mistakes and learn how to do it better each rocket you build....and there WILL be more. Have fun and enjoy the flight but most of all don't sweat it. An H flight is nothing more than a G with a longer walk.
I agree with the wood glue for wood and paper rockets. It has great strength and flexibility, and the bond to wood or paper is stronger than the materials being bonded. Plus, it is non-toxic. I really dislike working with toxic epoxy. I don't like having to wear gloves and take the other precautions. For a rocket like this, probably the only epoxy I would use would be some JB Weld for the motor retainer and the conformal rail guides.
 

qquake2k

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I was originally going to use a LOC IV for my Level 1 cert attempt, but ended up using a Minie Magg instead. However, I did build the LOC IV, and had several fun G powered flights with it. It was the first rocket I used high power building techniques on, and those techniques served me well through Level 1 and 2. All of the techniques I used, I learned here on the forum. Great bunch of people here!

I used an eyebolt in the forward centering ring for the recovery anchor. I put t-nuts in the aft centering ring, and made brass clips for retention (I now use 1/8" thick aluminum strips instead of brass). I used a short length of tubular Kevlar with a very long length of tubular nylon attached to it for the recovery harness. I used a 12x12 Nomex blanket to protect the chute and nylon webbing.


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