Looks mighty familiar...The Y-Harness arrived today, and has probably the beefiest swivel I've ever seen. All my other rockets have swivel-envy.
View attachment 373300
Looks mighty familiar...The Y-Harness arrived today, and has probably the beefiest swivel I've ever seen. All my other rockets have swivel-envy.
View attachment 373300
Can you tell me the final dimensions and dry weight as built?
The current weight is 17 lbs 13 oz without the recovery equipment (chutes, harnesses, nomex, etc). I need to get a better scale to get you the final numbers, though - my scale was purchased when I was doing smaller rockets.
I finally got around to wiring up the electronics bay (see post #9). I took some time away from this project to complete my Level 3 cert, so please forgive the delay.
Congratulations on the L3!
Jason,
Congratulation on successfully reaching L3 !
What did you fly for your L3 Cert ?
Now, the "fun" ( expense ) begins - LOL !
Dave F.
View attachment 386479
There was one small gully with water in it left over from the October Monsoon, and the rocket landing software found it:
Booster Assembly
I decided against fiberglassing the airframe. I had already cut on the aft end of the fin slots to fit check the fin can / motor mount assembly, and didn't have a way to hold the shape of the tube at the aft end while I applied the glass and epoxy. I would have also needed to epoxy the slotted tube, first coupler, and second main body tube before applying the glass, which would have required me to place the coupler exactly at the right height in the body tube before I installed the motor mount, else I would risk having inserted the coupler too far, which would force the motor mount tube further aft than is desired.
So, this step became substantially simpler without the fiberglass step. I added some epoxy inside the slotted body tube at the three locations I the centering rings would be placed and also added epoxy for the first coupler. Immediately after inserting the motor mount tube into the first body tube, I would insert the coupler so that it rests on the top centering ring of the motor mount tube.
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Once the tube was slathered with epoxy, I slid the motor mount assembly in through the back of the tube until the fin tabs met the top of the fin slots. After inserting the motor tube, I set the new booster section on the floor and slid the first coupler in from the top.
View attachment 371672
I then epoxied in the 15 inch upper tube for the booster, after first confirming (this time) that I could reach the U-Bolts to install the Y-harness later. I did test fit a quick link just to make sure I could install it as well since the clearance between the U-Bolts and the coupler is tight.
The final step here was to add some epoxy around the aft most centering ring and clamp the air frame to the aft centering ring.
View attachment 371671
Normally I would have installed the rail button t-nut before I installed the motor mount tube, but the set of 1515 rail buttons and t-nuts I had allocated for this project had an issue where the screws weren't the correct thread for the t-nuts (or had already been cross threaded and didn't work). Either way, I will install the aft rail button later by drilling in to the middle centering ring and epoxying the screw in there.
I also did a quick check with the second coupler to see how much I could insert it in to the booster section. The second coupler only inserted about 5.5 inches instead of the 7.5 that would mark the mid-point of the coupler. The instructions did note that the second coupler would not be able to go in to the midpoint, so I considered that a successful fit check. I also inserted my electronics bay to verify and it works also, but only if I adjust the switch band (which hasn't been attached yet) so that the switch band is not in the middle of the electronics bay coupler. Again, this may be desirable since the new LOC electronics bays only take up half the length of a 15'' coupler, which means attaching the switch band exactly in the middle of the electronics bay would conflict with the interior e-bay bulkhead.
**I have been carrying those orange handled spring clamps for years, but have never used them (I have others I like better). I'm glad I kept them as they were perfect for holding the airframe to the aft centering ring while the epoxy cured.
Have you considered the "slice and spread method" in lieu of actually cutting pieces out?
If your largest motor mount uses an aeropack retainer, the aeropack mmt adapters can be stacked inside that without requiring additional retainers.
Jason - Thanks for sharing this build thread! I just got a LOC VII for Christmas and had a question based upon this section of your build thread. I had planned to assemble the fin can externally as you did, then glass or CF each section of the body tube separately before gluing the glassed/CF'ed body tubes & couplers in place. One reason you stated you didn't glass was because you had cut the fin slots to test the fit of the fin can and couldn't keep the shape of the airframe while glassing. Was the other reason the placement of the thrust rings?
I had not anticipated those being problematic. Normally, I put mylar in the tube and use the couplers to hold it in place and keep the shape of the airframe, leaving enough space between the couple at the aft end of the rocket to cut the fin slots when the epoxy is "green". Would this approach not work due to the thrust rings (which I think are optional)?
Thanks!
I believe so. I obviously didn't explain my technique well as I think its the same approach as the "cut and spread" you mentioned. I typically cut through he fin slots through the bottom of air frame when the epoxy/glass is green, let them cure completely, then spread them apart to insert insert and glue in the fin can. I was just a bit perplexed about some other challenges Jason mentioned in his post and am trying to figure out if there is a way to work around them. I believe it has to do with the thrust rings in the kit. Thanks!
Most of the challenges I ran in to were due to inexperience with kits of this size AND trying to work out how the removable motor mounts might work.
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