Build Thread: LOC PK-3 Weasel (1.6" 29mm)

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messedupryan

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I won a kit at LDRS last week as part of the Silver Fleet Contest. My Little Bucky Jones was silver enough to win me a prize. A LOC PK3 - Weasel! This is far from a typical rocket for me. I've been a fan of short/fat and larger tube rockets. These slim, high fliers are something I've shied away from. After seeing many, many of this style rocket fly at LDRS I am kinda excited to have one to test out.

I've got a color scheme, and a name picked out already (which is odd for me). I feel like I need to make some other decisions as well before I get started. I'm eye-balling Aerotech F & G motors, and I'd like to have a screw on motor retainer that would accommodate. I am also looking at these surface mount fins and wondering if trying to figure out how to do TTW fins is worth it or not for this build.

I've never built a LOC kit before, so I'm looking forward to seeing how another manufacturer packages and documents a kit. Out of the box (bag in this case) I can already feel a nice difference in the weight of the nosecone. The tubes are nice and sturdy, and it looks like this will have a bulkhead and forward payload bay.

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LOC kits are ok. Good quality parts but minimum instructions and much left to the builder.

Read the instruction but then stop and think of what you want and plan it out.

I have build a few 1.6" LOC park fliers and a 2.26" IRIS from LOC kits.
All were 299 MM so used an Aerotech metal motor retainer JB welded on.

On all these had a very hard time getting the second spiral groove on the BTs filled. There is a hidden groove under the glassine layer that shows after painting.

Surface mounted fins should be fine. Just sand off the glassine layer then glue on. Added some fillets with Rocketpoxy and they will be plenty strong. Note that the fines are forward of the back end on the BT so will not hit the ground first.

Also plan out recover and shock cord attachments. Can't tell but the LOC kits I build had fairly thin Kevlar glued to the MMT. I used a much heaver Kevlar glued to the MMT since this is not easily replaceable.

Also added 1010 rail buttons instead of the rod lug. Both could be installed or just the lug.
Depends on what launch rod/rail you will have available.

The Weasel is a nice looking rocket so have fun building and flying it.
 
Aerotech metal motor retainer JB welded on.
Great news, this was what I was hoping to do.

On all these had a very hard time getting the second spiral groove on the BTs filled
I've never had good luck with this on any of my builds. Still working towards a glasslike finish of mine ;)

I used a much heaver Kevlar glued to the MMT since this is not easily replaceable.
This was the first thing I made a note to change!

Also added 1010 rail buttons instead of the rod lug
I am thinking about 1010 and a Lug for a rod, just for the flexibility.

Thank you so much for the great feedback, I really appreciate it.
 
yeah, what waltr said..

once you get to HPR kits, instructions are more of a suggestion! :D

Packing the chute is will be tight
Painting the NC will be a pain. The paint goes on fine, but doesn't really stay after a few flights! (All HPR 'plastic' NCs are finnicky to paint!)
Fillets take practice to get super smooth & perfect.. adding a sand-able filler to the epoxy helps!
Pin or make really tight the NC.. they can pop off with altitude, ejection / cord shock, etc..
37 layers of sandable primer to fill the spirals.. (or follow teh 10' rule: it looks good enough for 10' away..)
 
One of the guys I've mentored built a LOC kit for his L1. I agree that the kit was light on details. His kit included a baffle so that's where the shock cord was attached. I attach my shock cords to the MMT and use a protector to keep the shock cord out of the flame. Estes also has screw on retainers. They are about $10 each. They are plastic, but hold up well. Surface mounted fins should be fine as long as your not landing on a hard surface. If you are going to use rail buttons add them early in the build. I put mine on before the fins go on. I use a pair of long hemostats to reach down the tube. And have fun.
 
I love the LOC kits...others have already given you good advice but here is one more thing I see in your photo...That kit is from when LOC was located in Barberton, OH. LOC has changed ownership and is now located in Plymouth, WI. (Goes by LOC 3.0, as they are the 3rd owners.) The current LOC will still help you any way they can. Most "bits-n-pieces" are the same (or compatible) now as then.

One recommendation and a note....throw away the elastic shock cord. It's a number of years old, and probably dried out. Because the rocket separates at the payload bay; there is a lot of weight loading the elastic.
It looks like cardboard centering rings, LOC now has 1/4" plywood 1.6" to 29mm motor mount rings. They are nice if you are going to put rail buttons on, and want to screw into the ring.
https://locprecision.com/products/163rings
 
I won a LOC Weasel many years ago as a door prize at a NARAM. Love the kit. Eats F and Gs. I did a kevlar mod when building it. Unless you really want to fly it on anything over a G, well, I hope you have room for it. A really nice kit.
It fell to an Aerotech G71 red years ago before they knew that the propellant chemicals effected the delay.
Model has been repaired and has flown many times. Scarlet and Gray, every day.

Chas
 

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I put thin CA around the edges of all of the tubes before I had a chance to mash the edges.
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The Nose Cone is the most solid piece of plastic I have put on a rocket. This thing is Thicc! Got to work on sanding off the seams and the spots left from the mold. Then I used some 30 minute epoxy to attach the coupler to the upper Body Tube and attached the bulkhead and eye bolt.
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Added the 3 fins using TBII for now.
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I loaded this up in OpenRocket and with a G64-10 it tops out at around 400 mph and 540 ft/s acceleration. Is wood glue sufficient at these speeds, or should I consider epoxy fillets on the fins?

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Which ever YOU are more comfortable working with. Both wood glue or epoxy are fine. (I end up using a mix on a build this size.)
You can use plastic push rivets or small screws 2-56 (or) 4-40 to hold nosecone to payload bay. (Don't glue it.) That way you can put a tracker, or beeper, or altimeter, or.... in there. Don't rely on friction fit for nosecone to payload. (Like you said that nosecone weighs a ton, and a sudden stop at the end of an energetic deployment will loose it.
 
You can use plastic push rivets

This was exactly my plan, then the *thicc*ness bit me! The shoulder is so thick that the rivet won't close. I'm tempted to just trim the pin and let friction hold it. If I do that I will likely put 2 of them in the tube just in case 1 were to fall out. hrmmmmmmmm, decisions to make.

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Those rivets come in lots of lengths based on total thickness.
What size hole did you drill? PM me your address and I can send you a few longer rivets. (I think I am up to 3 diameters, and 3+ lenghts for each.)
[ The bad thing about living a few miles from McMasterCarr...I "will call" all my orders and always come back with a bunch of "stuff". ]
 
I’m waiting for a motor retainer, and some 1010 rail buttons, so I decided to work on the fins.

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Im still torn on how to handle the shock cord attachment. I think I am going to use these cardboard centering rings, so I don’t think I can wrap kevlar around the motor tube. I’m also going to have to figure out rail button placement they doesn’t interfere with the motor mount.
 
I have done the rear rail button a few ways.

On one LOC build, the MMT centering rings were wide so I marked were it would be then drilled through the ring and Tapped to correct thread. Then a few drops of Thin CA to 'harden' the card board. Once dry, run the tap in to clean up the threads.

My last LOC build, I glued a hardwood, spruce, block just int front of the rear centering ring. once dry sanded the block to fit in inside of the BT. After installing MMT assembly, drill, tap, AC so before.
 
Im still torn on how to handle the shock cord attachment. I think I am going to use these cardboard centering rings, so I don’t think I can wrap kevlar around the motor tube. I’m also going to have to figure out rail button placement they doesn’t interfere with the motor mount.
Not to highjack, but... what do people think of the fishing leader recovery anchor in the North Coast Rocketry kits? For those that don't know, one end goes around the motor mount, the other is just below the nose cone/payload shoulder and is the anchor for the shock mount. Seems easy enough to reach to replace the long Kevlar or elastic and if the wire gets hot enough to damage it something way worse is going to happen/has happened.

Homer
 
Homer,
I have never had an issue with the North Coast wire cable mount system. I have been flying them for decades. The only issue with the heat would be a motor blowthrough, but that would most likely toast the model before it damaged the cable.
I did work for NCR back in the early '90s. Cut a few feet of cable...

Chas
 
Made some great progress this week with the finishing touches. Primer and the middle yellow layer went on first.

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We had to stop the rocketry work to do some Elephant Foot Surgery.
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Next, we added Pink! I am planning to attempt to fade from yellow to pink or pink to yellow to blend these transitions. My expectations are low, but I really wanted to try some new things with this build.

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My niece chipped in on the project by donating various sizes of vinyl Daisies that we cal layer on the yellow part of the body.
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Just about every Weasel I've seen is / has some yellow on it!

to fade rattle cans:
(This does take a bit of practice though)

hold the can / nozzle about 45° to the rocket and spray in an upward motion / arc. sop you just 'touch' the rocket body with paint. the closer part of the spray cone should be heavier than the opposite side (which is further away).

Hard to really explain in words, but that's worked for me.. (but of course, there is a Youtoob video!)

 
Nothing beats the thickness and weight of a LOC kit. So nice to fly on bigger motors. Unfortunately, after building LOC, I don't even like flying many of even my larger Estes kits, because they're just so light.
 
@Tyler P I would argue that some LOC kits are overbuilt: overly thick & heavy tubes for their LPR "park" kits. (They are, after all, using motor mount tubes as body tubes for these!)

(And being an R/C pilot yourself, you should be following the mantra: "Build it to fly, not to crash" :D )
 
The heavy weight LOC park flyers let me fly bigger motors with all the attention grabbing sound, smoke, etc...BUT keep them low enough to not loose in our local small site.
Are they optimized for performance...no, but if not for them; we would be stuck with saucers, spools, tubefins, and other Odd-roc's, for big motor/small fields.
 
I found this same video! He made it look rather easy, I am going to practice tonight on some garbage body tube.

I found holding the rocket (on a stick in your left (or right, depending..)) hand, then stroking up / spraying in an upwards move while pressing the spray button helps "colour" the area you want. Then rotate the rocket as you go, adding colour..

Practice.. it does take a bit of 'fineness'..
 
@Tyler P I would argue that some LOC kits are overbuilt: overly thick & heavy tubes for their LPR "park" kits. (They are, after all, using motor mount tubes as body tubes for these!)

(And being an R/C pilot yourself, you should be following the mantra: "Build it to fly, not to crash" :D )

I just prefer low and slow, so even the PF line of LOC kits can do that, lol!
 
I found holding the rocket (on a stick in your left (or right, depending..)) hand, then stroking up / spraying in an upwards move while pressing the spray button helps "colour" the area you want. Then rotate the rocket as you go, adding colour..

Practice.. it does take a bit of 'fineness'..
I find it easier to have the part I'm painting below the part I'm fading into. I let gravity help keep errant paint drift from getting where I don't want it. Once you've done the fade area (which is relatively small), you can paint as normal. Here's one I did that fades red-orange-yellow-white-yellow-orange-red.
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Remember, the paint is gonna get jacked up on the first flight. Plus, once it's out on the pad, you really can't see any imperfections.
 
"Build it to fly, not to crash"
The heavy weight LOC park flyers let me fly bigger motors with all the attention grabbing sound, smoke, etc...BUT keep them low enough to not loose in our local small site.
Are they optimized for performance...no, but if not for them; we would be stuck with saucers, spools, tubefins, and other Odd-roc's, for big motor/small fields.

Both comments are correct, for their applications. All rockets crash, but crash-worthiness is optional for performance rockets. LOC tubes are tough, but maximum toughness is obtained using fiberglass.
Half my collection is Estes, though. Not tough or high performance, but (mostly) cheap and pretty.
 
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