LOC 7.6" Patriot Build

[n3tjm]

I finally got around to start working on my Secret Santa Present . Thanks to the Conspirators, they sent me a LOC 7.6" Patriot for Secret Santa 2021 and then for Christmas in July the Conspirators ordered me the fiberglass, kelvar, resin, and some tools I needed to build this bird the way I want to. Next year will the 10th anniversary of having my Nar L3 Certification, and the last time I flew anything bigger than a J motor was my L3 flight, I figure I want to fly this rocket next year to celebrate. Most likely with a M1350 since a M1939 won't fit no matter how hard I push.


I think the decision of glassing this rocket is a good idea. These body tubes are Huge, and the walls are thin. Without the glass, I don't think these tubes won't hold up for long. In preparation for glassing, I removed the Glassine layer form body tubes. I then epoxy the kevlar anti-zipper band onto the forward end of the booster section and payload section.


The booster tube is finished by attaching the shorter tube the slotted tube. This is where I had my first mishap. Since I was gluing paper to paper, and since the future fiberglass with be what will hold the tubes together, I decided to use wood glue to attach the two tubes together. This proved to be a mistake. I was not able to get the two tubes together before the glue bonded, and the tubes were not straight. So I cut the tubes apart, and removed the tube coupler. Since I ordered the e-bay option for this rocket, I knew I had an extra tube couple, so I decided to use the looser fitting tube coupler that was intended to attach the payload section as the new tube couple. This time I used epoxy and had no issues attaching the two tubes.


The motor mount mount and fin can assemble started by firing up Adobe Illustrator and making a templet to cut slots into the centering rings to accept slots that I am going cut into the fins. I tacked the aft and middle center rings together and used the templet to mark where I needed to cut. Using a ruler, I marked on the fins where I needed to cute some tabs. Then I had a date with my scroll saw and cut out of the fin slots and tabs.


After all the cutting, I got out my belt sander and went to town sanding the leading edges of the fins. I don't claim to be an expert at doing this, but I don't think I did to bad a job.

Now I am waiting for my AeroPack 75mm retainer to arrive to assemble the fincan. I could go ahead and glass the airframe tubes. However, I wonder if I should wait until I have the fincan built and installed before glassing the booster section? Opinions?

 

[wonderboy]

I think its best to glass that booster prior to installing the fin can. I honestly do as much prep as possible to the airframe prior to installing fins. Having fins sticking out just makes all other operations (filling/sanding/smoothing) more difficult.

Good luck, I'll be watching this thread with great interest!! (I'm a fan of the LOC 7.6" kits)

 

[n3tjm]

Got the booster tube glassed

 

[Hobie1dog]

cool project, keep the pictures coming

 

[JRL303]

Really nice progress. Love the pictures.

 

[n3tjm]

Got confirmation that the 75mm retainer is on its way and should have it on Saturday. I will wait for that to come in to build the motor mount. I think I will glass the top section tonight.

Also on its way is a RMS 54mm set. Not sure what the final weight will be but I think a K1103 would be a good motor for its first flight. K550 would be nice too if it is not to heavy. I already got permission to launch rockets on a friends farm, just gotta look into how to get a waiver .

Thought about asking the forum if anyone has a RMS 75/5120 they are welling to sell me for a good price, but I should pay off the 54mm set first. Besides, the M1297 flight won't happen till next year anyway.

 

[n3tjm]

As I mentioned earlier today, I decided to glass the top section tonight. Mrs. Elf decided that she wanted to help so I decided to let her... after all.... she "let me" buy that RMS 54mm set... and I did tell her how much a M1350 or M1297 will cost... Here she is painting on the resin.


After the tube was nice and coated I took over to apply the glass. She wanted to do that but I said this part took some skill. As you can see, it is a near perfect application

 

[Theory]

X2 on the K1103 for the first flight. love that motor!

 

[DMehalko]

X3 on the K1103x, my favorite 1706 load! And awesome to see the lady helping out!

 

[n3tjm]

75mm retainer came a day early so I started the motor mount assembly. I used the retainer to mark on the motor tube were the aft ring goes. I then decided to go ahead and install the blind nuts just in case. The for the sake easy installation, I just slid the mid centering ring in the tube. Then I epoxied the aft centring ring in place. The retainer is not yet cemented in place.

 

[kenstarr]

Ooh that is looking awesome! Can't wait to see the finished product!
Ken

 

[n3tjm]

Got the middle centering epoxied in place. Fins temporarily in place to keep ring in place.

 

[n3tjm]

Next step in the motor mount assembly is attaching the top centering ring. This part may be an oversight in the design. With the length of the motor tube the same length of the slotted body tube, that means the top centering ring is going have to go inside the tube coupler. However, the top centering ring does not fit inside the tube coupler. So, I'm going have to make the ring fit inside the couple. First I stuck the centering ring into the forward end of the booster tube and placed it flush against its tube coupler. Then I inserted the other tube coupler I had. Using a pen I traced around the joint where the coupler wall met the ring.


Then using my be belt sander I removed the wood around the pen marks, every once in a while testing the fit in the tube coupler.


Once I was satisfied with the fit, I epoxied the centering ring to its new home on the forward end of the motor tube.


While the epoxy cured, I worked on cutting out the fin slots on the airframe tube. Once that was done, I attached the u-bolts to the top centering rings on the top centering ring, using epoxy to secure everything.

 

[JackC]

As I mentioned earlier today, I decided to glass the top section tonight. Mrs. Elf decided that she wanted to help so I decided to let her... after all.... she "let me" buy that RMS 54mm set... and I did tell her how much a M1350 or M1297 will cost... Here she is painting on the resin.
View attachment 539704

After the tube was nice and coated I took over to apply the glass. She wanted to do that but I said this part took some skill. As you can see, it is a near perfect application
View attachment 539705

After you told her this part took some skill, I’m surprised she didn’t say, “I know…that’s why I want to do it!”

 

[n3tjm]

A update on the Patriot. Got the fins Glued onto the motor mount. The alignment of the fins is not perfect, but I guess it's good enough. Here the first two fins are glued into place.


All four fins are now glued in place.


The fin can test fitted in the body tube.

 

[Hobie1dog]

fillets will take a week to do as big as that thing is.

 

[n3tjm]

Yeah, and don't forget that there are internal fillets

 

[n3tjm]

My 54mm Aero Pack adapter came in and I tried them on to see how they look. I really like how the aero pack adapter system works. Once I find where I put my WB weld, I'll be glueing on the retainer to the motor tube.


Got the first set of internal fillets applied.

 

[n3tjm]

Discover a mouse nest in the kitchen bar overhang so I went to the hardware store to buy some mouse traps. While I was there I bought some more JB Weld. Got the 75mm retainer glued onto the motor tube.

I also got the final internal epoxy fillets done.

 

[n3tjm]

Getting so close to finishing the motor mount. The fins are further reinforced with 6oz fiberglass. The first two sets of fins are done. Once the final set is done, it will be time to attach the airframe tubing.

 

[n3tjm]

Been a while since I posted. Partially because I have been busy with my second job, and partially because I have done some more work on this just didn't post about it because I didn't take any pictures. Earlier I mentioned my fins were a little misaligned due to trying to slot the centering rings myself. This caused some issues with the fit in the airframe tube. I was just going enlarge the slots where needed, but my $18 including shipping Horrible Freight rotatory tool lived up to why I like calling Harbor Freight Horrible Freight, so I made do. So a big part of the delay was waiting for a chance to go to Hobby Lobby to get some 5 minute epoxy to see if that can help me. That way I can align and hold the "panels" between the fins in place while the epoxy set. It sort of worked. End result was more gaps then what I would of liked, But I'll take what I can get. One the epoxy had a day to set, I applied epoxy fillets to each tube and aft centering ring joints.


I use modeling clay as a backstop where the fins and slotted airframe extend beyond the aft centering ring. This will prevent the epoxy from falling into the huge gap there. I also mask off the first set of epoxy fillets for the fins.


30 Minute Epoxy is mixed and applied to the joint.


The masking tape is then removed and gravity does its job to smooth out the epoxy.


Now after this side is cured enough, another side will be done, rinse, and repeat until all four sides are done.

 

[Tim51]

Been a while since I posted. Partially because I have been busy with my second job, and partially because I have done some more work on this just didn't post about it because I didn't take any pictures. Earlier I mentioned my fins were a little misaligned due to trying to slot the centering rings myself. This caused some issues with the fit in the airframe tube. I was just going enlarge the slots where needed, but my $18 including shipping Horrible Freight rotatory tool lived up to why I like calling Harbor Freight Horrible Freight, so I made do. So a big part of the delay was waiting for a chance to go to Hobby Lobby to get some 5 minute epoxy to see if that can help me. That way I can align and hold the "panels" between the fins in place while the epoxy set. It sort of worked. End result was more gaps then what I would of liked, But I'll take what I can get. One the epoxy had a day to set, I applied epoxy fillets to each tube and aft centering ring joints.
View attachment 542311

I use modeling clay as a backstop where the fins and slotted airframe extend beyond the aft centering ring. This will prevent the epoxy from falling into the huge gap there. I also mask off the first set of epoxy fillets for the fins.
View attachment 542312

30 Minute Epoxy is mixed and applied to the joint.
View attachment 542313

The masking tape is then removed and gravity does its job to smooth out the epoxy.
View attachment 542314

Now after this side is cured enough, another side will be done, rinse, and repeat until all four sides are done.

Good job. Are you planning to T2T 'glass the fins ? I realise it's not necessary, just curious as to your preference.

 

[n3tjm]

Good job. Are you planning to T2T 'glass the fins ? I realise it's not necessary, just curious as to your preference.

Yes. It will prolong the life of the fins, add strength to the fin can as it will hit the ground first .

 

[n3tjm]

This morning before I went to work, I decided to apply a epoxy fillet to the top centering ring, airframe joint.


Later in the day, after working, taking the wife out to lunch, going to Ollies, and Tractor Supply, and getting Riley a File and Trim Service at Pet Smart and finishing the outing with an outing at the Dog park, I got right back to working on the Patriot.

It was time to get ready to Tip To Tip Glass. First thing I did was look for any "Low Spots" in the fillets. I was worried that this may create bubbles, so I fixed them with 5 minute epoxy.


One of the challenges of T2T glassing is the leading edge of the fiberglass. You want the transition between the two layers to be as smooth as possible to cut back on future sanding. One thing that really helps with this is placing asking tape on the glass, and then cut on top of the tape. The tape will prevent the glass from fraying, and the tape will come off on its own once it is wet with the epoxy.


I paint the first area with epoxy in prep for T2T glassing.


First piece of glass applied. Some of the glass is trimmed away. notice how neat the forward edge is?

 

[C.O.B.H.C.]

This morning before I went to work, I decided to apply a epoxy fillet to the top centering ring, airframe joint.
View attachment 542914

Later in the day, after working, taking the wife out to lunch, going to Ollies, and Tractor Supply, and getting Riley a File and Trim Service at Pet Smart and finishing the outing with an outing at the Dog park, I got right back to working on the Patriot.

It was time to get ready to Tip To Tip Glass. First thing I did was look for any "Low Spots" in the fillets. I was worried that this may create bubbles, so I fixed them with 5 minute epoxy.
View attachment 542915

One of the challenges of T2T glassing is the leading edge of the fiberglass. You want the transition between the two layers to be as smooth as possible to cut back on future sanding. One thing that really helps with this is placing asking tape on the glass, and then cut on top of the tape. The tape will prevent the glass from fraying, and the tape will come off on its own once it is wet with the epoxy.
View attachment 542917

I paint the first area with epoxy in prep for T2T glassing.
View attachment 542916

First piece of glass applied. Some of the glass is trimmed away. notice how neat the forward edge is?
View attachment 542918

Are you going reinforce the coupler? This is an area I've seen people over look way too many times. They'll glass the airframe but forget to reinforce the coupler.

 

[tsmith1315]

I already got permission to launch rockets on a friends farm, just gotta look into how to get a waiver .

If you're TRA, to get insurance coverage, send in the landowner permission form here. Link is top right:
https://www.tripoli.org/content.aspx?page_id=22&club_id=795696&module_id=468946

If you're NAR, there's a link towards the end of this page to email for landowner permission/insurance info:
https://www.nar.org/safety-information/

To file for a COA/waiver from the FAA, follow the instructions that NAR has graciously provided here:
https://www.nar.org/high-power-rocketry-info/filing-for-faa-launch-authorization/

They say to file 45 days in advance, and you can request the COA through the end of the year. I've heard that some agents/areas will allow 2 years, mine will not, but they only took 2-3 weeks for approval.

 

[n3tjm]

Are you going reinforce the coupler? This is an area I've seen people over look way too many times. They'll glass the airframe but forget to reinforce the coupler.

Before this question, I have not given it much thought. Do you think that will be necessary? The centering ring is near where the two airframe tubes are joined and both airframe tubes are glassed as one unit.

 

[C.O.B.H.C.]

Before this question, I have not given it much thought. Do you think that will be necessary? The centering ring is near where the two airframe tubes are joined and both airframe tubes are glassed as one uni

I believe it is necessary if you plan on flying an M motor in this rocket.

 

[n3tjm]

Got all four sides glassed. This pretty much finishes the construction of the airframe! Now onto the finishing steps. Got some runs I need to sand down, and I plan to paint the entire rocket with epoxy again. I will allow a full several day cure for another sanding, and then get ready for Bondo then primer and filler work. Not sure if I will paint it this season, or wait until it gets warmer to paint. Primer does not care about the cold. Paint does.

There are a couple things left that need constructed. Rocksim predicts I will need about 4 lbs of nose weight for 1.5 Margin of stability to fly on K motors, and 8 lb with a M. Actual weight will be determined when I get everything together and get an actual location where the CG is (It may differ where Rocksim thinks it is). I am going use the parts that came with the kit for the 54mm adapter and use that to make a Nose Weight mount inside the nose cone. That way I can fly it on smaller motors with less nose weight, and then if I fly it on an M I can swap out a heaver nose cartridge.

Also, next up on the assembly block is the electronics bay. I have another Eggtimer Quantum ordered. So I will be using two of these for dual deployment. LOC's 7.5 " E-bay is interesting where the e-bay part only takes half of the space of the tube coupler. This gives you more space for the recovery system, but it does make it interesting of where to put the switch band. Normally the band will go right in the middle of the tube coupler so you have equal coupler for each section. But this is not going going work here. The part that goes into the lower section is going get the short end of the stick. The reason for this is the vent holes need to be below the top bulkhead.

I am going use two screw switches to power on the each altimeter, and the wifi will be used to arm the altimeter. I will probably just use 9vt batteries because I am not familiar enough with anything else. I know the wifi modules are power hungry so people recommend not using 9vt batteries. Not sure what to buy and don't have any chargers for them. If someone can linky me a good place to get batteries and a charger for them, or have something to send me that would be great.

Now if I can get my Fusion 360 working... I want to make mounts to vertically install the Screw Switches to the bottom of the top bulkhead, so they can be turned on through the vent hole, and still be removable if they need to be serviced.

For recovery, I am thinking about a Rocketman 12' Parachute. I wonder if its possible specifying the color, and if so is it only limited to 2 colors. Can I go with 3? Does it cost more to ask for specific colors?

 

[jmasterj]

For recovery, I am thinking about a Rocketman 12' Parachute. I wonder if its possible specifying the color, and if so is it only limited to 2 colors. Can I go with 3? Does it cost more to ask for specific colors?

It doesn't cost more but it will take (much? depends on the time of year) longer to receive.