L2 Build Terminated

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Willie - I finally got around to prepping my kit and I have a few questions. What is the length of your boat tail? Mine measures 15" and I think I saw in the rock sim file it is listed as 12.15". My MMT is 36" but with the added length of the boat tail, the MMT falls too short.

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Willie said:

Scott Evil also noted earlier in the post that he too had issues with the motor mount being to short. He indicated that his motor mount was 36" long, but it was too short for his setup. He did not know specifically why.

My boat tail was modified during this build to remove somewhere near a 1/4 to 1/2". It now measures 12 1/4" (way shorter than yours). The motor mount stick about 3" above the top center ring (sitting on the top of the fins).

I'm very curious if your boat tail is significantly less tapered than mine. Does your MMT fit nicely through the boat tail end?

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I guess it is less tapered as my MMT is not snug at all. There is a good 1/8" clearance all around. There is enough room for the retainer to fit inside the tail cone. Wildman subbed my tail cone & NC with one similar to yours as he said he was out of stock with the filament wound ones. Guess I need to send Tim a message and see if he sent me the wrong one. By the way, did your NC coupler fit in the NC with ease? Mine is very tight.

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Willie said:

Giving Tim a call is probably in order for either a different boat tail, or longer motor mount tube.

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Contacted Tim yesterday regarding my MMT length - he shipped a longer one today! Great customer service!

By the way Willie, yours is looking good!

Another question - are you planning on using 2 altimeters or just 1? What about charge cannisters?

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I wouldn't worry about having the same brand altimeters. It's the little things that get ya.

I had twin Ravens sitting on power perches in mine at MWP. The older one (#69) had issues powering up the night before so I wired the redundant Rocketry Warehouse aluminum bulkheads to the second Raven.

...24" drouge came out at apogee (7400' on an L935 btw)...I then watched it "puff" smoke out the static port twice before landing in standing corn without the 60" Recon that I just bought from Tim. (No damage...I DARE you to break one of these things)

Moral of the story...I used the same Triple 7 FF that I used many times before but packed it a little different due to how close the charge tubes are to each other. I was pretty confident I had them tight enough...apparently not.

Have FFFF BP for nexr flight.

Just trying to point out how over thinking one aspect can lead to overconfidence in another.

OK...shameless selfie of Echo Charlie Four now...lol

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Aeropoxy ES6209 has about 50 times the viscosity of West 105 (50000 cp) I use it for basically everything however the full cure time is very long so you have to be patient.

Willie said:

Just finished up the last of the internal fillets. Next up is filling in internal fillet access holes, and completing the external fillets.

I don't want to attempt the external fillets with West System Epoxy and filler.

What would be a better epoxy, that already has higher viscosity, for doing the external fillets?

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I've had good success with Rocketpoxy.

Willie said:

Just finished up the last of the internal fillets. Next up is filling in internal fillet access holes, and completing the external fillets.

I don't want to attempt the external fillets with West System Epoxy and filler.

What would be a better epoxy, that already has higher viscosity, for doing the external fillets?

Click to expand...

I've used both Rocketpoxy and Proline 4500 with good results for my external fillets. Only problem with Rocketpoxy is you need to let it set about 20 minutes before applying to get all the bubbles out. The wait also lets it thicken up so it wont run.

RocketPoxy is very easy to use. Just be sure to wait long enough after it's mixed for fillets. You want it too "stiffen" up a bit, so it will hold the shape when pulling the fillet.

The way I tell is dip mixing stick into it.....pull up a spike in the middle. If it settles back...not ready. When the spike holds it shape...ready.
Here in south where it fairly warm when I use it....7-80 temp that mean about 15 minutes.
When I've been building up North in 55-65 temps it can take as long as 45 minutes to stiffen after mixing.

I mix on cardboard sections rather than mixing cup, then spread it out flat while its resting so any bubbles can rise to surface, which you can't do in a cup.

Mix just like JB Weld.....2 big lines next to each other, 1 resin, 1 hardener. Very simple to figure what's needed. No pumps, no weighing.

You need to find the sweet spot for your local & ambient temp. But like anything else rocketry related, there is always a bit of a learning curve.

Curious... had problems using WEST for fillets ?

Edit: Yes I like Proline [black stuff] also. But it can be very messy to use & you WILL get black residue on anything it touches. Wear old clothes and cover everything near by.....but when done properly the results are beautiful. Need a scale for this, mixed 5.5 to 1 by weight & much shorter pot life.

15-20 minutes vs 45-60 for RocketPoxy. The RP comes with black dye to color the fillets or other colors can be purchased for a variety of colors.

Looks like a very fine job on your building! Good luck with flights and have fun.

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Are you using 1010 rail buttons?

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THE END

Ummmm.........what happened?

s6

Yeah, good question ???


JD

stealth6 said:

Ummmm.........what happened?

s6

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Echo Charlie Four was my most stressful build to date. If fact, it was almost the last straw of my marriage.
I got way too sucked into it. Take a breather...it's just a rocket.

why?