Cj builds WM Mach-2 rocket [2-stage]

Our thoughts and prayers are with you. BTW I used your e-matches on a six D12-5 cluster for my N-1 Russian Moon rocket and they worked great.

Hey Jim,

I hope you have a complete and quick recovery, we'll all keep you in our prayers.

Best regards,
Fred

blackjack2564 said:

I have not done anything on any of my builds since late March.

On April 6 I underwent Open-heart surgery.:dark:

1 valve replacement, and double bypass. This was totally unexpected & has screwed with my life quite a bit.
I have been out for just 3 weeks and started my re-hab today.

So until I am cleared to build stuff again , everything just sitting in Limbo. I think Airfest in Sept could be my first launch if everything goes well, so we shall see..............

Cannot lift arms above my shoulders, or weight over 3lbs etc..etc....etc.. No driving till june/jJuly. List of stuff to recovery is long as arm.

But to answer....I have much to do to finish this & my other builds. [2-stage Nike-Apache & Punisher 2 -stage rebuild]
Fit the I/S coupler...add all electronics & recovery etc.... I will document when i do it. Just pulling the lever on my drill press is a no-no right now.

Was hoping to fly a high thrust 2 grain 54 [J-460-T] or Warp-9 etc in booster and a 6 grain white thunder in sustainer...for shakedown flight.
After that a 6Xl whatever I can buy, at the time for booster [L-935 hope] to a 38mm Mellow longhorn in sustainer.

That should kick it in the butt.

Click to expand...

CJ. I will fly one for you. I hope you recover soon.

Jim, I sincerely wish you a speedy recovery. Rockets can wait, take care of yourself.

Jim, man sounds unexpected - pray for a speedy recovery. Glad to hear they have everything fixed and likely you will be doing much better soon - but a major surgery! My mom had similar surgery and is doing very well afterwards.

Stay low - rockets aren’t going anywhere. I expect you will have some extra time on your hands during your recovery to get caught up .
Be good!

Jim, as said by others, best wishes for a speedy recovery. When you're back on the air, I've got a question about how you set up your sustainer/upper section.

I am building mine single stage, so I guess I'll be sitting at the kids table this year. But I do want to shove an L935 in there. And I want to use positive motor retention, vs. just tape. I'm willing to friction-fit a DMS motor but I don't want to risk loosing cases. I will use the Aeropack CTI forward closure adaptor on top of the motor, and I will fabricate a forward retainer. My plan is to bond a bulkhead at the right place in the tube, With a slightly oversized hole in the bulkhead, the threaded rod from the motor adaptor will project into the upper compartment, and I can secure it from the top side.

I don't have an L935 handy right now (every time I get one, it disappears into my Darkstar 3, and then the Darkstar 3 disappears for a couple of minutes and comes back with just a spent liner). CTI's specs show the case (not including the thrust ring/rear closure) as 25.14" and the charge well on top of the motor extends another 0.6" The Aeropack retainer is another .625" (5/8ths) for an overall length of 26.37" overall. So if I mounted the bulkhead at about 26-3/4 from the bottom, I'd have a bit over 6" of open tube on top of the bulkhead. The AV bay/coupler will fill 3" of that space, leaving around 3" of a 54mm tube to hold the shock cord, the attachment hardware, a small drogue and blanket, and a deployment charge.

Does my plan and the dimensions I'm citing sound right? Anything I'm not thinking of?

I can tell you what I am thinking--an L935 in a 4 pound rocket? Oh Hell Yeah!

When does you doc say you can return to flying? I can go fetchem for you when you return.

CJ, had no idea, so sorry to hear what happened. Hoping you're back at a rocket field flying crazy like normal soon!

Dad Man Walking said:

Jim, as said by others, best wishes for a speedy recovery. When you're back on the air, I've got a question about how you set up your sustainer/upper section.

I am building mine single stage, so I guess I'll be sitting at the kids table this year. But I do want to shove an L935 in there. And I want to use positive motor retention, vs. just tape. I'm willing to friction-fit a DMS motor but I don't want to risk loosing cases. I will use the Aeropack CTI forward closure adaptor on top of the motor, and I will fabricate a forward retainer. My plan is to bond a bulkhead at the right place in the tube, With a slightly oversized hole in the bulkhead, the threaded rod from the motor adaptor will project into the upper compartment, and I can secure it from the top side.

I don't have an L935 handy right now (every time I get one, it disappears into my Darkstar 3, and then the Darkstar 3 disappears for a couple of minutes and comes back with just a spent liner). CTI's specs show the case (not including the thrust ring/rear closure) as 25.14" and the charge well on top of the motor extends another 0.6" The Aeropack retainer is another .625" (5/8ths) for an overall length of 26.37" overall. So if I mounted the bulkhead at about 26-3/4 from the bottom, I'd have a bit over 6" of open tube on top of the bulkhead. The AV bay/coupler will fill 3" of that space, leaving around 3" of a 54mm tube to hold the shock cord, the attachment hardware, a small drogue and blanket, and a deployment charge.

Does my plan and the dimensions I'm citing sound right? Anything I'm not thinking of?

I can tell you what I am thinking--an L935 in a 4 pound rocket? Oh Hell Yeah!

Click to expand...

All CTI 54mm 6G-XL motors are plugged. You'll need to check your individual L935 but if it's fairly new it will already be threaded for positive retention. If it's an older "pre threaded" plugged closure then you'd have to use the Aeropack adapter for positive retention. Otherwise you can order a threaded plugged closure from Wildman and swap it with the one in your L935.

I hope you're feeling better Jim. Take care bud.

Dad Man Walking said:

CTI's specs show the case (not including the thrust ring/rear closure) as 25.14" and the charge well on top of the motor extends another 0.6" The Aeropack retainer is another .625" (5/8ths) for an overall length of 26.37" overall. So if I mounted the bulkhead at about 26-3/4 from the bottom, I'd have a bit over 6" of open tube on top of the bulkhead. The AV bay/coupler will fill 3" of that space, leaving around 3" of a 54mm tube to hold the shock cord, the attachment hardware, a small drogue and blanket, and a deployment charge.

Does my plan and the dimensions I'm citing sound right? Anything I'm not thinking of?

Click to expand...

Take a look at Jim's second-to-last photo in post #18 - the switch band does not end up in the center of the coupler, so you'll have an inch or two less in the lower airframe because of that.

I'm starting to put one of these together now myself, and I didn't think I could make everything fit "comfortably" with a 6XL case, so I'm building around the regular 6 grain case. I'm planning to fly a K260 and a K660, either of which should be a personal high altitude for me.

I'mm .....baaaackkk!

In full force, got driving privileges back, can pull handle on my drill press. So I can use power tools etc.

First off...thank you for all the nice notes & kind words from the past few weeks. All were read & much appreciated, helped quite a bit, as there were several times things were not so good, and they cheered me up.


Well enough of that...LOL I'm working on this Mach -2 today, upper stage, putting all the guts in.... to make it flight worthy. Plan on going to Camden, my local launch this weekend. First rocket thing I've done since Jan.

You can easily fly 6xl's in this thing, so no worries there. 5-6in between motor & edge of tube. With my av-bay and long charge holders hanging down there's about 1.5 in left of room, plenty to stuff 20ft of 1/8 kevlar and a drogue in! [space between charge holder also]

Took break to post this...back to work & some pics later!

Glad to hear you're back in action Jim!

Glad to hear you got through it all and are back in action CJ! You must be hanging out to get your hands back into the build pile.

Good new Jim. See you there.

Welcome back Jim! I'll see you at Camden during the July launch.

All the best,
Fred

blackjack2564 said:

TIP:
1 Fin gets a couple drops of CA to hold on airframe after aligning on pencil marks.
This keeps fin guide in place while tacking on the other 3 fins with epoxy till cured.
No more having stuff slip-sliding all over the place, while trying to tack/glue fins in place.

Then break off the CA'd fin. sand root clean & airframe. Acetone wipe.
Re-attach with epoxy to airframe, while using the other 3 fins to hold fin guide in place.

Click to expand...

Och! that's brilliant.

Woohoo! Go, go, go!

I'mm .....baaaackkk!

Click to expand...

Usually I read all your threads but hadn't been following this one (no waiver/NOTAM high enough to fly Mach 2 in the UK + no Wildman dealer either! :sad so learned of your surgery just now. Very sorry to hear of your health crisis and very glad indeed to read it's sorted and you're back in good health.
All best,

Let's try a new post. I reserved several to keep continuity flow, but our new Forum site won't let me go back and edit/add to those posts. Hopefully that will be fixed. But for now.
I flew last weekend the sustainer test for functionality with a small 38mm motor H-148 red. It was ugly, but I'm getting ahead of my self.

First the electronics a Missleworks RRC3 added to custom sled cut to fit perfectly into the NC coupler.
Held on to tie rods with small ties & notched on ends to go over eye bolt nuts. Tie rods are #6-32 all-thread, to keep it light & gain a bit of room.


Note the charge holders are threaded to act as stops for tie rods. I only use them on apogee side where needed for high altitude. 1.75 inch long....[.5]inch diameter...with 2-matches holds 1 gram BP [which was too much lol]
No room in NC with Main, they don't fire until 700 ft, so it matters not. The power wire is run through hole in sled to act as strain relief.


using a single cell LiPo 850 milli amp battery. tape is just to keep wire in place.
3rd channel [staging] setting written on tape, so I can keep track.

When prepping I will use 2 matches per charge, since for testing, just using one altimeter.
Wrap tiny piece of tape around metal on match head, then add second match. This is done for both apogee & main. This is main charge & will be inside glove tip/BP. I like to hook up just matches first, power up altimeter to get OK....then add BP. [power off, of course]



For charge barrels The match heads are kept up high...on top of BP, NOT under in bottom where it could blow out the BP partially unburnt. With match on top, firing down into BP...the BP must go past burning match to exit, ensuring fully burnt charge!



Note 2 match wires are run through 1 hole on each bulk plate , keeping thing neat. When using 2 altimeters, same hole with 2 wires used, no need to double up matches. Wire carefully stripped and twisted together trimmed to about 1/4inch before installing into terminal. Then always use "pull" test to be sure of good contact. I pull test EVERY time I hook anything up.



By the way here is redundancy chart of those interested in chance of failure with more than one match..

Recovery used in 54mm NC [Head end Deploy] 36in. Spherachute in a 9 in. nomex burrito, with 12ft of 1/4in. Kevlar cord. For Apogee a 18inch Spherachute drogue, they are very small, being measured over top of canopy & pack well in tight spaces,placed in a 6 in. nomex burrito, along with 22 feet of Kevlar cord. This pic showing bundle size ready for install. The shock cord goes in first, then burrito. 2 shearpins used [2-256 nylon]
Drogue in fincan below av-bay [not shown]



Showing 36in chute. Open 9inch nomex.



I had 1 gram BP in charge barrel, apparently too much, should have ground tested.
Shortly after apogee, the main came out. No big deal that day, no wind & only 1800ft. Upon landing this is what I found.....



Yeuupp...blew motor mount out the airframe. Makes no sense as NC is so loose, it falls right off. Remember fins are surface mounted, so they don't lock MM in, it's free floating so to speak. There is a coupler glued in front, acting as a motor tube block & the whole shebang was epoxied in. Just not enough surface area I guess, but never expected it to come out the back.

Further investigation revealed the culprit....Whip-lash!
Charge power amplified by gun barrel and both parts came to ends of shock cord. Knots holding cord on told the story, they were pulled tight, ya would have thought this thing had 50 flights on it! It snapped so hard, flung MM almost completely out the back.

So I'll clean it up and re-glue everything and cut charge to 1/2 gram AND ground test this time...[I know better] when you get lazy, it will bite your behind. Cr gets more glue. Cord harness is solidly mounted, glue is just clear.



This is why I always want my first flight low enough to see all events.

This was a great story with a completely unexpected plot-twist at the end. It’s great to be reading CJ posts again. I hope both you and your rocket have a speedy recovery.

Hey, welcome back CJ. We’ve missed you.

Jim, I did the same thing this past weekend with my BH 38. I was testing with a 29mm motor with an adapter. 1st flight the main got deployed at the top and my adapter was hanging half way out the back. I used 1g of bp in the booster. Ooops! Next flight used .5g and everything worked perfect. I ground tested the main charge but not the booster.

blackjack2564 said:

This is why I always want my first flight low enough to see all events.

Click to expand...

Or you could just do this:


Actually it was low enough to be seen from ground

Hi Jim,

I’m so glad to hear that your surgery went well. Take all the time that you need to heal. The entire Rocketry community has been helped by your extensive detailed posts. We all wish you a speedy recovery.

All the best,
Bob

I'm behind on this thread, just saw Jim's flight report. I'm putting finishing touches on mine (single stage only) for a trip to Black Rock in a couple of weeks. I'll use something sane (with a threaded forward closure for retention) for the first flight, but if all goes well I have an L1000 DMS at the ready.

Couple of questions for the more experienced folks here:
(1)


Thanks in advance!

blackjack2564 said:

Click to expand...

I like seeing the insulation on the wires twisted like that for mechanical support of the bundle. It is a trick (continuing the twist up the insulation) that not many people realise.

Dec 2018
Great to be building again, this and the Nike-Tomahawk will keep me busy for awhile.

This link will take you back to post #20 where I left off with I/S coupler build.
They have graciously restored my ability to edit this thread so I could again use the blank reserved post to keep the flow on track.

https://www.rocketryforum.com/threads/cj-builds-wm-mach-2-rocket-2-stage.144264/#post-1759987

Great build thread with lots of tips. Preparing to build one now, single stage, so this is all valuable info. Thank you!