Loc Pk-66 Ultimate; Now a build thread w/pictures.

[grouch]

That's hot.

 

[Wallace]

Thank you Sirs. I'm thinking some sort of spring clip(s) that would go on the retainer screws to both retain and somewhat shield the airstart wires. I know I've seen what I need, just cannot remember where. Maybe painting/picture frame spring clips?

 

[Wallace]

Found it! Duh, light bulb finally went on, pulled a picture off the wall and found these nifty little spring clips. If it were cut to the correct length and drilled to go on the retainer mounting screws , should make a nice wire retainer/clip dealy to keep 'em secure and out of the exhaust plume. Thinking maybe a small groove carved in the thrust plate to guide the wires (wire guide?) then just lift the clip and fit 'em in. Only thing I'm not so sure of is weather or not they'll cause problems with igniters getting jammed up at ignition instead of just blowing out. Anyone have any experience with this?

 

[Wallace]

Obviously would cause me grief if I commandeered 'em from her picture. Guess I'll have to go find my own

 

[Wallace]

Time to stick some fins! Decided on gluing 2 opposing at a time would be easiest for accurate alignment seeing that they're 180 degrees apart. Scraped a bit of paint where they attach to the thrustplate, put down some blue tape and lightly tacked 'em w/some 30 minute epoxy. I know I said Titebond 2 from here on out....But, I got scared about potential heat soak w/7 motors crammed in that tight space. Figured landing damage would be a likely result with heat softened wood glue. You can see how they actually attach to the thrustplate at the bottom edge of the root, figured it couldn't hurt right? I like to fly cameras so roll control is important to me. Spinning videos are not my fav. I've been spending alot more time making sure to get alignment accurate to the best of my abilities. Last 2 I've built and flown have both shown at least some success with having a total of 370 degrees of roll under power. Hope this has same or less..

 

[Wallace]

Hardened the motor tubes with thin ca and did interior fillets with Rocketpoxy last night (I know,I know, I said no more epoxy but I keep convincing myself that it really is necessary, in this case I didn't feel Titebond would bond tightly since I already had epoxy smeared everywhere from my awkward attempt at tacking fins w/15 minute B.S. crapola.) Last time I'll use it for anything, totally brittle, very little bond strength. You really shouldn't hear crackling noises when applying minimal force to a glued joint and then having said joint fail almost immediately. Pre and post "glue" mmt weights were surprising which led me to start this thread on weights of commonly used adhesives. https://www.rocketryforum.com/threads/weights-of-commonly-used-adhesives.148385/ . As per usual, motors no longer fit the tubes so a bit of grinding was in order. Flapper made it relatively painless. They work much better in a pneumatic die grinder but cordless was within reach so I took the easy path. If you don't already have one of these, drop everything and go get one. Rocketry is full of radii or according to Merriam Webster, radiuses is also acceptable (but sounds really wrong) so any radiused type tool tends to be appreciated.

 

[Wallace]

I mixed up 6 gram batches of Rocketpoxy, 1 for each pair of fillets. After applying what seemed to me to be "most" of each batch, I assumed I added approximately an ounce total. What surprised me was the pre weight of 570.1 grams and after curing weight of 579.5 grams. Either my scale is unreliable, my methods unsound or epoxy loses weight as it cures/dries out. Since epoxies don't technically "dry" I never really gave it any thought but does epoxy have this trait in general? Is there something in the makeup that evaporates/out-gasses that would account for this? Anyone else notice this?

 

[Wallace]

Made some progress on the Ultimate is the last few days. Tried a couple different color schemes on the tubes. Stood back and looked at it and...No like. Beauty of MonoKote is you can go right over it as long as it laps "correctly" in keeping the airstream from lifting the edges. Tried this layout and said ok, good enough. It's way more difficult trying to keep things neat/un-messy having to build post finishing. It's certainly not perfect but I'm calling it "pretty good".There was a seam sealer product that chemically bonded the edges but I cannot find the actual product or info on what it contained. Guess I'll have to experiment. I know for a fact that methanol does not affect it because that's what I've been using to clean up sticky messes. I have acetone, MEK and PVC glue on hand, one of those should work? Anyhow: Here's a couple pics of my fillet down the edges of the MonoKote plan. Undecided at this point weather or not it's a good idea. We'll know after it flies, possibly at Midwest Power in a few weeks if everything comes together.

 

[Wallace]

Managed to find some spare rocket building time over the last 2 days. Decided there was too much white going on so added a red pinstripe in the usual spot that makes the nc look proportionately longer. Turns out it's stupidly difficult to wrap a thin strip of slippery plastic that shrinks out of straight/parallel when heat is applied. After battling it for a minute or two, I came up with this. Just wrap the white overlay at the same time to stabilize the whole mess. Naturally I rushed it and ended up with a few wrinkles. The white isn't truly opaque but you can't tell from 5 feet.

 

[Wallace]

Cut/sanded and wrapped the switchband.

 

[Wallace]

And here's where she stands to date...Obligatory messy house/cat/door jamb pic for scale..Pretty happy with the way the fillets turned out. They added huge amounts of stiffness to the bottom end. I felt they were absolutely necessary due to the lack of a centering ring at the top of the fin tabs. There was a lot of give in that area pre fillet. The fact that they pin down the edges of the MonoKote is an added bonus. I did lightly sand the vinyl and Rocketpoxy seems to play fairly well with plastic, time will tell if they actually stay in place.

 

[Wallace]

Also managed to put together yet another Quantum l ate last night. I really enjoy building these things but with the vision problems and all the magnifiers It tends to turn into a headache inducing affair.

 

[DM1975]

That looks great!!!

 

[Wallace]

Thank you. I'm pretty happy with it so far. I have a fear of finished rockets tough, just know something bad'll happen to it..

 

[Wallace]

Almost forgot, weight is at 59 ounces right now. I'll probably end up adding half that again in electronics and recovery so it won't be a lightweight.

 

[Andrew_ASC]

Nice cluster build.

 

[Nytrunner]

I have some concerns that the cat will crowd the main chute too much in the payload bay. Will putting it in the drogue compartment shift the CG too far back?

 

[Wallace]

Not if you insert him tail first...

 

[Wallace]

Serves as a standoff thereby keeping the major mass forward.