Chris' Punisher 4 L3 build

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No, it's on the bulkhead. Usually the chute in the deployment bag will pull right out of the cone when you pull in the shock cord.
 
No, it's on the bulkhead. Usually the chute in the deployment bag will pull right out of the cone when you pull in the shock cord.

Yeah, I was iffy on this in a number of nosecone only deployments (note, not all head end), but have moved to always putting charge opposite of opening. Haven't had problems since.
 
Dang! Sorry to hear this, Chris.

HED is apparently a sometimes thing. The suggestion of placing the deployment charge opposite the opening with the chute in between is probably the best way to insure that nothing gets hung up inside the nosecone.

Have been having some issues getting a Chute Release set-up to work every time. The Chute Release has always worked but have experienced a few tangles. I feel your frustration.
 
Yeah, I was iffy on this in a number of nosecone only deployments (note, not all head end), but have moved to always putting charge opposite of opening. Haven't had problems since.

Sorry to hear about the jammed chute Chris! :(

I have had great success placing the charges on the bulkheads of head end deploy birds, but I'm using a smaller chute (Top Flight 58") and potentially smaller cordage. Griffin has a P4 same as mine, he uses a larger chute, and does place the charges as the tip. If I recall correctly, you will need much(?) more powder if the charges are at the tip.

For reference sake:
[video=youtube;EQO5JNwcBpc]https://www.youtube.com/watch?v=EQO5JNwcBpc[/video]
 
I'm using 2.0 grams for the drogue with one nylon rivet as the shear pin. I use 1.5 grams for the main with 3 nylon rivets.

Like I said. I think I'm going to swap things around so that the altimeter bay is in the middle with the main in the payload section. I have a 22" section of 4" tubing that's empty right now. All it's doing is keeping the camera bay and altimeter bay apart. I can use a 10" section to keep the bays separate and use a 12" length as a parachute compartment.
 
At least the altimeter did the job- it was just more of a charge problem than anything else. I agree with the other posters- I've only flown my punisher 4 once, but I also had the charges up in the nose so it's pushing downwards.

Third try's the charm, right? :)
 
Chris, it was good to see you and Jacob at Dairy Aire! Sorry to hear about the recovery problem. It was a beautiful boost, and when the drogue came out, I figured it was a done deal. I only heard about the problem later and didn't get a chance to see you again at the launch. Better luck next time --- when you do get it, you will have really earned it!
 
It was good to see you too Thirsty. That's funny, I thought it was a done deal too. :facepalm:

You're right, I will have definitely earned it. :bang:
 
My plan was to pull the loose fins off the booster, sand the epoxy off the fins and the booster and then reattach the fins. Well, I tried pulling the fins off the booster last night. They are loose but I couldn't get them to pull more than 1/16" away from their original locations. I looked inside the MMT and it looks like the fillets are still attached to the fins. Any suggestions? Maybe heat?
 
My plan was to pull the loose fins off the booster, sand the epoxy off the fins and the booster and then reattach the fins. Well, I tried pulling the fins off the booster last night. They are loose but I couldn't get them to pull more than 1/16" away from their original locations. I looked inside the MMT and it looks like the fillets are still attached to the fins. Any suggestions? Maybe heat?

If you can inject epoxy where you need it just re-epoxy them. Or foam fill the can. I wouldn't heat the fins. Before the fillets fail the fins might suffer permanent damage.
Can you get the fins out by slotting the body tube to the aft end?
 
Injecting more epoxy was my backup plan. There's no way to slot the tube because the thrust plate/motor retainer is in the way. I'll have to find some thinner epoxy. At the moment all I have is Rocketpoxy and BSI 30 minute. I don't think I can get the Rocketpoxy to flow into the gap at the root of the fin and I wouldn't trust the BSI stuff. I think rebuilding this booster is going to be more work than it was to build it in the first place. :sigh:

If you can inject epoxy where you need it just re-epoxy them. Or foam fill the can. I wouldn't heat the fins. Before the fillets fail the fins might suffer permanent damage.
Can you get the fins out by slotting the body tube to the aft end?
 
Injecting more epoxy was my backup plan. There's no way to slot the tube because the thrust plate/motor retainer is in the way. I'll have to find some thinner epoxy. At the moment all I have is Rocketpoxy and BSI 30 minute. I don't think I can get the Rocketpoxy to flow into the gap at the root of the fin and I wouldn't trust the BSI stuff. I think rebuilding this booster is going to be more work than it was to build it in the first place. :sigh:

My experience with loose fins is cutting small windows in the airframe that allowed me to use a set of files to re-prep the motor tube surface. It needs to be cleaned out really well too before reapplying epoxy. I also reinforced the fixed internal fillet with some strips of fiberglass. It's not particularly easy but it's good when trying to keep costs down. The second time I had a loose fin (different rocket), I just built a new booster section.
 
Unfortunately, I have considerable experience with this scenario.

I can't see it to tell you , so these are MY choices:

1. Internally....if there is enough fillet attached to motor mount & or fin that is solid and would make for a good CA joint. Use that. Squirt liberal amount of CA into slot...let drizzle down to joint and move to spread it., hold to set.

Remove exterior fillet with sharp wood chisel & sharp blow. Hit just right, they will shatter off quite easily. I can remove fillet off both sides of 1 fin in 10 minutes. Use opposite side of chisel normally done. The bevel side[ upside down] to fillet will prevent "digging" into fin or frame. Set blade against fillet not under it.

...................WARNING..................
Wear some kinda glasses doing this, the shattering epoxy WILL hit you eventually...lol

2. if fin is totally loose or close. Have some one hold airframe horizontal on table, or if alone stand on airframe, with fins hanging over edge.
while you '[using mallet] come at back of fin with an upward/forward motion, hitting trailing edge. Surprisingly in every case for me [4 rockets from Gizmo to Ultimate Wildman] this will knock fin clear out of slot. may take 3-5 whacks, and don't spare the motion, whack the hell out of it. Will shatter interior fillet coming through slot, or distort it enough for reminding fillet to come out clean.

Then remove any fillet still on fin with above method or grinder.

This really works well, UNLESS you have done the 2 internal fillet thing...one set on motor mount & one set on fin/airframe. I for one would still try it.


Your right, it way simple building new, rather than fixing old. I came about ''My technique" after becoming so frustrated I didn't give a dam any more and just wacked the snot out of a fin...to my surprise!!!!!! IT came out....LOL

In any case Chris.....shame about all the bad luck ya been having.
Next flight, do the rocket godz dance around the pad & kiss the rocket goodbye. This will guarantee successful flight!:smile:
 
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SUCCESS!!!!!

CJ must have sent me a subliminal message because when I got home today I decided to try a chisel and hammer. I got the outer fillets off in no time. Once I got those off I could see that the internal fillets hadn't flowed out as well as they had in the past. This set of Rocketpoxy had been open for at least a year. The internal fillet had a blob right under the outer body tube. I put the chisel in the BT/fin joint and gave it a couple good whacks at each injection point. The internal fillets popped off the fins and I was able to pull them out of the body tube. The next issue was that there were big chucks of broken epoxy inside the BT that were too big to come out of the slots. I cut a hole between the two fin slots using a 2" hole saw and shook all of the pieces out.

I need to sand the left over fillets off of the body tube and fins then I'll be ready to put it back together again.
 
Thanks CJ.

I've put all of this energy into engineering the crap out of everything for this project and I've had all kinds of problems. It's been frustrating at times but I'm learning from it.

Unfortunately, I have considerable experience with this scenario.

...

In any case Chris.....shame about all the bad luck ya been having.
Next flight, do the rocket godz dance around the pad & kiss the rocket goodbye. This will guarantee successful flight!:smile:
 
I say we all fly out to CA for your next L3 flight and have a big party afterwards, you will have definitely earned it! It's gotta go better next time, proof that crap happens because we all know your build skills are there. Until then we are following the build.
 
How did your flight video turn out Chris? I hope you camera did ok... I suppose that after the booster landed, the camera/payload section slowed down just before landing under drogue?
The videos from your on-board sony setup are excellent.
 
Thanks CJ.

I've put all of this energy into engineering the crap out of everything for this project and I've had all kinds of problems. It's been frustrating at times but I'm learning from it.

Ummmm, You'll be better suited for the future than someone who zips off L1, 2 and 3 real fast and then starts having a bunch of failures thereafter 'cause they got lucky with the rapid certifications. Didn't acquire experience that
some of the hard knocks you've had. Believe it or not, there are others who are aware of your situation and are taking it to heart to try to avoid a similar event. Nothing wrong with that. Kurt
 
I tested the camera on the bench and stopped recording using the phone app. When we got to the pad the camera was dead. I think the wifi on the camera killed the battery. I think I had turned the auto shut off function in the camera. I need to do some testing before the next launch.

How did your flight video turn out Chris? I hope you camera did ok... I suppose that after the booster landed, the camera/payload section slowed down just before landing under drogue?
The videos from your on-board sony setup are excellent.
 
I took a good look at the parachute to NC fit this morning and I think I understand why the parachute stuck now. The parachute needs to fit into a space roughly 8" long, 4" diameter on one end and 2" diameter on the other. I cut the end off the broken NC just below the eye bolt so I could see how the chute packed into it. Before the flight I had folded it into thirds. When I tried packing that into the NC it was a tight fit in the 4" section of the NC and it wasn't using much of the space towards the tip of the cone. I tried folding it in half and it slid in almost to the eye bolt. It was still pretty tight though. I also had to pack it just right to get it to fit without having to jam it in. I'm sure that folding it into thirds and leaving it that way for a week caused it to hang.

After that I folded the parachute in half and packed it into a 8" section of 4" coupler. The chute fills the space but doesn't need to be crammed in to fit. It also sides right out when the coupler is tipped over.

So here's my latest plan:

1. Glue an 8" length of BT to the front of the camera bay. The altimeter bay coupler will slide into that tubing and use 6x 4-40 screws to attach the two sections. It will leave about 1" between the bulkheads in the bays for the ejection charge leads.

2. Glue an 8-14" length of BT to the front of the altimeter bay for the NC coupler to fit into.

3. Glue a bulkhead into the NC in the FRONT of the coupler. Glue the NC couple in. The main will be placed inside the NC coupler.


This is a compromise between a more conventional dual deploy layout and the HED layout that the Punisher uses. I'm not drag racing or going for altitude records so a little extra tubing isn't going to bother me. I'll still need a couple pounds of ballast to make it stable.
 
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This morning I got the tubing cut, one 8" section to join the camera and altimeter bays and one 14" section for the payload bay for the main chute. A 14" payload bay leaves me with a 6" parachute compartment. It's a snug but not tight fit. If I recess the bulkplate into the NC coupler a couple inches the parachute will fit without any gymnastics. I can't see any reason why I shouldn't so that is what I'm planning to do.

I also got all of the epoxy sanded off the fins. I love my 6" disk/ 4"x24" belt sander. :)
 
I'm making great progress today. I might be able to get the rocket ready to fly again by next weekend.

1. Glued the body tube sections to the altimeter and camera bays with 30 minute epoxy.
2. Glued the coupler into the nose cone with 30 minute epoxy.
3. Glued four 3/8"x3/8" hardwood blocks around the perimeter of the 2" hole I cut into the booster body tube.
4. Used Rocketpoxy to glue piece of body tube back over the hole.
5. Used a palm sander with a 60 grit to remove the old external fillets and sand the patched area of the BT smooth.
6. Glued one fin back onto the MMT with Rocketpoxy.

Some of you have commented that my rockets always fly very straight with almost no roll. I think it's because of the jig I use to mount them. I made this a couple years ago. I clamp a piece of scrap the same thickness as the fins between the halves of the jig.

IMG_4770.jpg

IMG_4769.jpg

IMG_4768.jpg
 
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Some of you have commented that my rockets always fly very straight with almost no roll. I think it's because of the jig I use to mount them. I made this a couple years ago. I clamp a piece of scrap the same thickness as the fins between the halves of the jig.

View attachment 320906

I really do like that jig. You're making great progress with the repairs.
 
Here are the graphs from last weekend's flight. The boost was very straight. Other than the fact that the main stuck it was a perfect flight.

Punisher 52117 Data.JPG

Punisher 52117 Graph.jpg

Punisher 52117 Earth.JPG
 
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Here are some pictures of my flight. Notice the Mach diamonds and 6+ foot plume.

ImageUploadedByRocketry Forum1496324018.573028.jpg

These three were taken by Ben Kolland:
ImageUploadedByRocketry Forum1496324449.707044.jpg

ImageUploadedByRocketry Forum1496324460.119514.jpg

ImageUploadedByRocketry Forum1496324470.545088.jpg

A couple more from Steve Jurvetson:
709A4120.jpg

709A4121.jpg
 
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After a long hiatus I finally got back to work on this project this weekend. I dry sanded with my palm sander, primed, wet sanded and painted.

I need to drill a couple shear pin holes andredo the ground testing for the main. Other than that she's ready to fly again.

IMG_5284.jpg
 
I look forward to seeing your flight(s) at the TCC October Skies Launch, assuming you'll be there.
 
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