LOC-VII Build Thread

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jmuck78 said:
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.
Click to expand...

Thanks for the info!
 
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.
 
After spending some time debugging one of the altimeters, I gave up and replaced it and conducted the deployment tests using an Eggtimer Quantum and 2.3 grams of black powder for both the main and drogue sections (see post #12).

The good news is that both deployments look sufficiently energetic. The bad news is that the Recon Recovery 60 inch chute I used as the main chute wasn't sufficiently protected during the test, and it now has a 3 inch hole in it. I'm going to try to repair the chute by sewing on a patch. Anyone have experience with this?
 
I posted the launch report in post #13.

UPDATE: I added the launch video from the ground - the video is a bit too far away, but its there.
 
Last edited:
I update the launch report with some additional photos and a video in post #13.

If any additional pictures from NSL show up, I will post them here. I think that wraps up this build thread.
 
Ez2cDave said:
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
Click to expand...

Thanks, Dave! I flew a 4'' Wildman Extreme on an M1500G at Lucerne Dry Lake. I was testing out a new water finding algorithm on the GPS tracker, and it worked. There was one small gully with water in it left over from the October Monsoon, and the rocket landing software found it:

WIM_0503_3.jpg IMG_7817.jpg
 
jmuck78 said:
There was one small gully with water in it left over from the October Monsoon, and the rocket landing software found it:
Click to expand...

Jason,

Hmm . . . Flying in a desert and you manage a "splashdown landing" . . . Murphy must have been sitting on your shoulder that day - LOL !

Congrats, again on the L3 !

Dave F.
 
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!


jmuck78 said:
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.

View attachment 371670

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.
Click to expand...
 
Have you considered the "slice and spread method" in lieu of actually cutting pieces out?
 
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!

Wallace said:
Have you considered the "slice and spread method" in lieu of actually cutting pieces out?
Click to expand...
 
Interesting discussion about the MMA and using a retainer. As I tend to overbuild and try to be hyper-safety conscious, this dialog has been helpful in informing my approach to this biild.

If I understand correctly, the safest approach would be to use the 75mm MMA with the aeropack 75mm to 54mm adapter to safely distribute the forces appropriately?

As Jason noted previously, John Cocker's test determined the plywood de-laminated before the glue joint failed; yet glassing the plywood made it roughly 2X stronger. As such, would there be benefit to glassing (vacuum bagging) the aft centering ring and the one on the MMA?

Steve Shannon said:
If your largest motor mount uses an aeropack retainer, the aeropack mmt adapters can be stacked inside that without requiring additional retainers.
Click to expand...
 
Knundrm said:
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!
Click to expand...

I would suggest glassing before you cut the slots - that would solve my initial problem with trying to hold the shape of the booster section with the slots already cut. I didn't use thrust rings, as I thought it might be over-constraining to use both thrust rings AND the removable motor mount. If you feel like its doable to get the thrust ring installed correctly and still allow the lower thrust ring to butt up against and loc to the bottoms of the fins, that might work ok too.

Also, I don't have a lot of experience glassing airframes, so I was a little reluctant to try it on two rockets at the same time before I was really comfortable with the technique. Since the booster section has two sections of airframe that need to be joined with a coupler, I had preferred to joint the two sections first and then glass the airframe so that the glass layer covered the seam (adding stiffness at the higher stress location). I was also worried about losing access to the inside of the tube where the harness would need to be attached, so I just decided to build it without the fiberglass coating.

All in all, the rocket performed very well without the fiberglass layer - at least on the first and only launch... Hope that helps!
 
Knundrm said:
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!
Click to expand...

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.
 
I have been out of rocketry for a while but getting back into it. Like the looks of the LOV VII. Have a question hoping someone can answer for me. About the nose weight for this rocket. Jmuck78 you stated it didn't need much if any. Probably only be able to fly on J-L. So with that info would it need nose weight with an altimeter bay for those motors? Obviously would check CG and all before flying but just trying to see what was need before I begin on this. Thanks.
 

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