(Slow Build) L3 The AGM Special
- Thread starter jfcote
- Start date
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In previous posts I forgot to mention that I sanded all the surfaces to be glued with a corse sanding paper and wiped them with acetone.
The fines are now all attached and I started the filets between the motor mount and the fins. I mixed a 40 grams batch of epoxy, so 20 grams for each filet.
The fines are now all attached and I started the filets between the motor mount and the fins. I mixed a 40 grams batch of epoxy, so 20 grams for each filet.
I completed the internal filets between the fins and the motor mount with the Proline 4500. I had some large gaps between the fins and body tube. I used West System epoxy that I heavily thicken with the West 406 Colloidal silica filler to fill from the inside of the body tube. I used green painters tape on the outside to prevent the epoxy to ooze out.
This week, I will work on my external filets and hopefully next weekend, I will install the last centring ring and the motor mount.
This week, I will work on my external filets and hopefully next weekend, I will install the last centring ring and the motor mount.
Wondering where you found the screw switch? I'm looking for one now to DD my Zephyr.
R-
spigalau
Well-Known Member
They are made by Feather Weight. Many vendors carry them.
https://www.featherweightaltimeters.com/av-bay-components.html
https://www.missileworks.com/store#!/Power-Switches/c/5760490
and Wildman
Sorry, I have been slow to post updates.
The lower section is almost all done now, will just need to add the top rail button, a vent hole and shear pin holes.
I use the Proline 4500 for the external fin filets. Then I glued in place the rear centring ring with West System epoxy that I heavily thicken with the West 406 Colloidal silica filler. I did the same for the filet of the top centring ring. Finally, I used JB Weld to attach the motor mount.
At this point the rocket with the recovery weight 467 oz. At this point it will probably gain an other with the electronics and completing the nose cone with the tracker enclosure. I will have to update the sim to see if I need to add weight to the nose cone. I plan to complete the e-bay wiring, the nose cone assembly and ejection testing this weekend. It will leave me a bit of time for maybe a paint job. I also need to enter my rocket to the LDRS BFR.
Finally, it was nice to know that Wildman received my motor
The lower section is almost all done now, will just need to add the top rail button, a vent hole and shear pin holes.
I use the Proline 4500 for the external fin filets. Then I glued in place the rear centring ring with West System epoxy that I heavily thicken with the West 406 Colloidal silica filler. I did the same for the filet of the top centring ring. Finally, I used JB Weld to attach the motor mount.
At this point the rocket with the recovery weight 467 oz. At this point it will probably gain an other with the electronics and completing the nose cone with the tracker enclosure. I will have to update the sim to see if I need to add weight to the nose cone. I plan to complete the e-bay wiring, the nose cone assembly and ejection testing this weekend. It will leave me a bit of time for maybe a paint job. I also need to enter my rocket to the LDRS BFR.
Finally, it was nice to know that Wildman received my motor
Threemorewishes
Well-Known Member
- Joined
- Feb 23, 2009
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Looking good JF! Good luck on the flight.
Thanks
The build is almost complete.
I added the other rail button to the lower body tube. I used a a nut with a nylon insert to secure it. It protudes a bit inside the body tube. I don't think it is an issue since it is all nicely rounded. I also drilled a 0.25" pressure relief hole. That section is now in being painted.
The color scheme will be: flat black for the lower body tube, orange for the top body tube and I will keep the nose cone as is. It is an old style fibreglass cone with a nice gel coat.
I drilled 2 x 0.25 holes in the switch band to vent the e-bay properly. They will also be used to access the two screw switches. I used 3 x #6 screws to secure the upper body tube to the e-bay. Inside the e-bay, I used some JB weld to secure brass knurled nuts.
I added the other rail button to the lower body tube. I used a a nut with a nylon insert to secure it. It protudes a bit inside the body tube. I don't think it is an issue since it is all nicely rounded. I also drilled a 0.25" pressure relief hole. That section is now in being painted.
The color scheme will be: flat black for the lower body tube, orange for the top body tube and I will keep the nose cone as is. It is an old style fibreglass cone with a nice gel coat.
I drilled 2 x 0.25 holes in the switch band to vent the e-bay properly. They will also be used to access the two screw switches. I used 3 x #6 screws to secure the upper body tube to the e-bay. Inside the e-bay, I used some JB weld to secure brass knurled nuts.
Last edited:
I glues the top bulk plate to the nose cone. Based on my updated simulation I will have a stability of around 1.2 at the launch. I think it is enough safety margin. Hopefully, I don't have to add any weight to the nose cone.
I also started to build the tracker holder that will be lodged in the nose cone. I am almost done with it. I will post pictures of it once it is completed.
To do:
I also started to build the tracker holder that will be lodged in the nose cone. I am almost done with it. I will post pictures of it once it is completed.
To do:
- complete the wiring of the electronics,
- complete the tracker holder,
- ejection charges test,
- update L3 documentation, and
- complete the paint job.
I conducted the ejection test. For the apogee, I used 3 x 2-56 nylon shear pins with 4 grams of 4f BP. I got a nice clean separation. I will use 4 grams for the primary charge and 5 grams for the backup one at apogee + 1 second.
View attachment 20240525-IMG_5559.mov
For the main. I used 3 x 4-40 nylon shear pins with a 5 grams ejection charge. I got a nice strong separation. So 5 grams for the primary and backup charges. For both tests, the fins dug in the lawn!
View attachment 20240525-IMG_5560.mov
Unfortunately, I got an issue. Some of the ejection gases made their way to the inside of the e-bay. Also, because the fit between the coupler and the upper body tube is on the loose side, I found some BP residues on the coupler. I don't remember how tight I got the e-bay. So on launch day, I will ensure that the e-bay bulk plates are very tight and I will add some tape around the edge of the bulk plates.
On the picture you can see where the gases made their way inside the e-bay.
Anybody had to deal with a similar situation? What was your fix?
View attachment 20240525-IMG_5559.mov
For the main. I used 3 x 4-40 nylon shear pins with a 5 grams ejection charge. I got a nice strong separation. So 5 grams for the primary and backup charges. For both tests, the fins dug in the lawn!
View attachment 20240525-IMG_5560.mov
Unfortunately, I got an issue. Some of the ejection gases made their way to the inside of the e-bay. Also, because the fit between the coupler and the upper body tube is on the loose side, I found some BP residues on the coupler. I don't remember how tight I got the e-bay. So on launch day, I will ensure that the e-bay bulk plates are very tight and I will add some tape around the edge of the bulk plates.
On the picture you can see where the gases made their way inside the e-bay.
Anybody had to deal with a similar situation? What was your fix?
Last update before the event
I completed everything except one more coat of paint tomorrow.
The electronics. I tried to keep it simple and clean. I used yellow wires for apogee charges and green for the main. The two screw switches are secured to the side. I used a few drops of ca glue after they were screwed in place. The battery compartment has a cover. It will be secured by two zip ties for the launch. The terminal blocks are secured in place by some double sided gorilla tape and zip ties.
I will use Home Depot 9v batteries since they are type 6LR61. There is on interesting article on 9v batteries at: https://www.missileworks.com/9v-success .
I completed everything except one more coat of paint tomorrow.
The electronics. I tried to keep it simple and clean. I used yellow wires for apogee charges and green for the main. The two screw switches are secured to the side. I used a few drops of ca glue after they were screwed in place. The battery compartment has a cover. It will be secured by two zip ties for the launch. The terminal blocks are secured in place by some double sided gorilla tape and zip ties.
I will use Home Depot 9v batteries since they are type 6LR61. There is on interesting article on 9v batteries at: https://www.missileworks.com/9v-success .
Several years ago, I experimented with the laser cutter available at my local library. It is a good thing that I kept all the parts. I had enough of them to make the pod for my BRB APRS tracker. It is secured to the base of the nose cone bulk plate by 3 screws.
Well, I mentioned that with my updated simulation, that the distance of the CG to CP will be about 1.2. Since I will only have the motor at the field and can't do the real measurement right now. I decided to add 1lb of weight to the tip of the nose cone. I used lead shots with epoxy. To ensure that the new weight will stay in place, I inserted a 1/4" wood rod.
