Convert any Wildman Jr kit to a 2 stage build [Vindicator JR]

CCotner said:

I was thinking about this the other day-several clubs don't allow metal rail guides because they 'chew up the rails', but in my experience launching exclusively metal rail guides for the last year, I haven't seen any damage whatsoever. I think the issue is that the Acme rail guides have tons of slop room; they're much smaller than the size they need to be. This means that if they're on really, really straight, they don't rub at all, and they don't gouge the rails. However, it (possibly) means that if you put them on crooked, or misaligned, they could actually be fairly far off and the rocket would still fit into the rails-but it would gouge the rails by jamming the sharp edges of the metal into the sides of the channel. It might be the case that the metal guides only work fine if they're very straight.

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I've read that some clubs ban rail buttons made of metal but specifically allow Acme guides.

Oops, brain fart. I meant PML.

https://www.publicmissiles.com/secure/components.asp?groupid=17

crossfire said:

I didn't know AT had rail guides for sale?

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I saw this https://www.rocketryforum.com/showthread.php?60865-Request-for-build-thread & since Wildman sold a butt load of JR 2-stage kits thought I should finish/resurrect this thread as it serves as a construction manual.

I left off needing to mount rail buttons. Here are pics of how to mount them on the booster. You mount them basically in the same location on the sustainer BUT ahead of the bottom CR [or they will stop the coupler from going in.LOL]

So the bottom button goes up a few inches from bottom of airframe & the upper button moves up equally the same.

You must have 2 on the sustainer, how else can you fly it by itself?
You won't always fly in the 2-stage configuration will you?:smile:


I have to find the log on what motors I flew it on and how high it went..... later on that.

I had a question on how you set up your rocket to break the igniter wire when the rocket separates at apogee. Do you just twist the wires together and tape? Also, did you put a terminal block on your ebay bulk head for both the igniter wire and apogee charge or do you wire directly to the altimeter? If the latter, how did you prevent the wire from pulling out of the altimeter?

Thanks for a great thread! I was just reading this for my 2-stage jr build.

The apogee charge is wired directly to my altimeter[as it always is]
The staging pyro that lights the sustainer motor is attached to the terminal block. It [wire]has always broke .... close to..... or at the terminal block for me. [with no damage]

There are other ways to do this: you can use a quick connect such as molex connectors used for RC & LiPo batteries.

You can use a short wire lead connected to the terminal block & the igniter wire wrapped to it & taped. Jim Jarvis uses this method & if you are reading this Jim, please post a pic of your method.

You can put electronics in the interstage coupler & use a separation charge at motor burnout, then using electronics in sustainer fire the motor. If it drag separates then it's a mute point.

You can put 2 conduits in the sustainer & run both the separation charge & ignition charge from electronics in the sustainer. I have not tried running both through 1 conduit as it seems really tight just for one. Possibly using a smaller gauge wire [shooter wire] may yield 2 wires through 1 conduit & attaching the ignition to them at the motor.


One of unique things about flying 2-stage rockets is the level of complexity it CAN, or can NOT add to the flight & how you as an individual decide how to handle these choices.


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You must also realize by making the choice to fly 2-stage rockets, you are taking on a burden of flying SAFELY...I cannot overemphasize this!

I ALWAYS arm my staging electronics first with the igniter hooked up, but OUTSIDE the motor. This is to ensure everything is functioning correctly . If all is a go, then & only then do I insert my igniter into the motor, & continue with pad prep. [after power turned off] Yes it has paid off. There was an instance where the igniter fired, the instant power was applied to the the electronics. This would have been disastrous, had it happened were I standing on a ladder next to the sustainer and the motor lit! Turned out to be a defective altimeter. It had been flown before, just decided to malfunction then. [do they ever pick a good time?]

I always make sure the area around the pad & ladder are clear of people & objects in case something does go amiss & I must jump clear.


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Make sure you have a clear understanding of how your electronics function & the settings they feature. If you are not clear, even by the tiniest amount, ask someone or call the maker of the unit.

If it's your first rodeo, practice the hook-ups with igniters , arm your gear making sure everything functions perfectly. Have a checklist and USE it. Before sticking motors in the stack.

"The arse you save, may be your own."

Start out simply, save the fancy stuff till after you have a couple of successful flights i.e: lengthily staging times, cutting timing too close, doing exotic settings.

Have someone helping you. It will take at least one extra set of eyeballs to keep track of where the booster is going while you are watching the sustainer. Or 2 people tracking if using those.

Personally I like using motor eject for the booster, with a properly sized chute, to eliminate complexity on the booster side for those just beginning.

Don't aim for the moon the first few flights, just get everything working correctly, is an accomplishment in itself.

Be sure of your motor choices. The booster motor MUST be able to lift the full stack quickly and have enough thrust to handle the TOTAL weight of the stack INCLUDING motors.
These are just my recommendations & are by no means written in stone.

Any others well versed in staging, any hints to help would be appreciated as I know many first timers will be reading/building/following this thread.

This is the year of the 2-stage, & I want everyone to have fun, be successful and fly safe!:wink:

blackjack2564 said:

I left off needing to mount rail buttons. Here are pics of how to mount them on the booster. You mount them basically in the same location on the sustainer BUT ahead of the bottom CR [or they will stop the coupler from going in.LOL]

So the bottom button goes up a few inches from bottom of airframe & the upper button moves up equally the same.

You must have 2 on the sustainer, how else can you fly it by itself?
You won't always fly in the 2-stage configuration will you?:smile:

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+1 on buttons for the sustainer. I asked about this in Post #24 and decided to go with just two buttons and an ACME rail guide higher on the booster to support the stack; thinking no buttons on the sustainer for less drag. There I am on the ladder having just armed the air start and it occurs to me... what would keep this sustainer going straight if it lights on the pad? :y: Fortunately it worked out okay that time, but rail buttons on the sustainer from now on.

Looking forward to hearing about your Vindicator Jr 2 stage flight.

blackjack2564 said:

You can use a short wire lead connected to the terminal block & the igniter wire wrapped to it & taped. Jim Jarvis uses this method & if you are reading this Jim, please post a pic of your method.

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If you're visualizing a terminal block external to the bay, then it wasn't me. I run the staging/separation charge wires through the bulkhead and epoxy them in place. Then I attach the wires to something such as the eyebolt so that when the tug comes, the electronics don't get yanked. Then I use breakwires (twisted and taped).

blackjack2564 said:

You can put 2 conduits in the sustainer & run both the separation charge & ignition charge from electronics in the sustainer. I have not tried running both through 1 conduit as it seems really tight just for one.

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I have a two-stager with a conduit that I run two wires through. Just has to be sized correctly.

blackjack2564 said:

You must also realize by making the choice to fly 2-stage rockets, you are taking on a burden of flying SAFELY...I cannot overemphasize this! I ALWAYS arm my staging electronics first with the igniter hooked up, but OUTSIDE the motor.

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The process of arming the staging electronics (actually, all of the electronics) with the ignitors not installed is absolutely essential. It will catch almost all problems. It should be done just prior to putting the rocket on the pad.

blackjack2564 said:

I always make sure the area around the pad & ladder are clear of people & objects in case something does go amiss & I must jump clear.

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I no longer allow anyone within 100 feet or so when I arm the electronics.

blackjack2564 said:

Don't aim for the moon the first few flights, just get everything working correctly, is an accomplishment in itself.

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Good advice, Conservative Jim

blackjack2564 said:

This is the year of the 2-stage, & I want everyone to have fun, be successful and fly safe!:wink:

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I agree! I think I've tried at least 8 of them this year (some of them even worked!). Two-stagers are fun, but must be done with much caution. I think an important part of that is to start from day one using an approach that inhibits sustainer ignition if things are not going well. Powered lawn darts, cruise missiles and flying out of the waivered area should not be part of the two-stage adventure.

Jim

CJ, I just unpacked my Jr Two-stage upgrade and I am thinking about the interstage coupler. Is the 38mm tube nested inside the 54mm tube the most simple way to go? I am wondering if I put a ring inside the 54mm coupler for a bulkhead to sit on, that could be the top of a 54mm av-bay instead of a 38mm one--more room for a 'conventional' av-bay setup and eliminate the 38mm inside tube altogether. What do you think?

And, in terms of the most simple way to go, it seems it would be easier to blow the booster off with the sustainer motor ignition than have a charge to separate them. I am sure I would lose a bit of max altitude that way, but I am not trying to set any records. If electronics in the sustainer light the sustainer motor, you could even go motor eject for the booster recovery. Or, just something simple like an RRC2+ for an apogee event only.

What is the path of least resistance but max reliability and ease of prep?

You hit the nail on the head......I would just leave the guts out & go for a more standard set up with 2 tie rods & eyebolt to attach cord to for booster.

Yep motor will blow the sustainer off...that's how I do it for simplicity sake. It's glass & can handle it. I do have a alt. in there........just to see how high booster goes.

Call me over the next couple days & we can discuss.

What's a good motor combination for the first flight. I don,t want it to go too high first time up.

Also do I need fo use an ematch to fire the sustainer motor or can I use the igniter that comes with it?

RayGNJ said:

What's a good motor combination for the first flight. I don,t want it to go too high first time up.

Also do I need fo use an ematch to fire the sustainer motor or can I use the igniter that comes with it?

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Which 2-stage kit & what does it weigh? This thread is about converting any Wildman Jr kit.

Depends on the motor you are using in the upper, if it's a CTI then you can use the supplied e-match with just about any electronics.

What are you using for staging electronics? That will determine what kind of igniter to use.
Most dipped igniters supplied with motors require 12 volts to fire they are designed to be used with launch 12v systems. Some are dipped matches and will work though.

Need exactly what you are flying to give a more informed answer

RayGNJ said:

What's a good motor combination for the first flight. I don,t want it to go too high first time up.

Also do I need fo use an ematch to fire the sustainer motor or can I use the igniter that comes with it?

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CJ comments are right on, but here's some "in the neighborhood" info to consider.

I've been running a few sims on a Darkstar Jr booster and Wildman Jr sustainer...didn't really find a combo that flew it reliably that went very low. Smallest motor combo I think I'd trust (sim wise) is a I357T or I245G booster and H123W or H148R sustainer combination (going 59 fps off the rail--sustainer ignition 1 sec after booster burnout)--which *still* takes it to 5000'! For comparison, a J510W booster and J500G combo takes it to 15k.

I plan to use CJ's e-match like devices CA'd into a BP substitute pellet at the top of the AT motor for ignition. I tested this recently and it makes an AT motor ignite near instantly...like a CTI motor. If I had a CTI dealer nearby, I'd just go Pro38 and call it done.

Double post

Its a WM Shape shifter jr. Its got a MW RRC3. Have not weighed it yet.
Flew as single stage on a AT H180 to 999ft.
I have the hardware for AT and CTI. Looking to try an I in the booster and an H in the sustainer.

You double posted...

Didn,t come up the first time.

Any update on this from the OP? I'm interested in a Jr kit with the 2nd stage upgrade and I'd like to see what you think of it. I'm also interested in how it performed compared to how it simmed using Wildman's rocksim file.

Great thread by the way.

Think I'm just about ready to start my Darkstar 2-stage I procured during "Black Saturday"! I believe I can get it with just what CJ has posted above....

[CarVac there is room (barely), so you don't have to notch the coupler. Here is a my dry fit with AP retainer removed to show the conduit against the coupler.]

I don't seem to have room for the interstage coupler. The brake line is tight up against the motor tube, and the motor mount fits snug into the body tube, but there is not enough room for the coupler to fit between the brake line and the body tube. If I notch an inch of the coupler, it should work, but will that degrade the strength of the coupler too much? There will still be about an inch not notched to fit inside the body tube. I've also thought about filing the top and bottom of the brake line down to make the outside diameter thinner (flatter) but doubt that will get me enough space to make the interstate coupler loose enough for drag separation. I don't want to flatten the inside diameter because the 3/16 inch brake line is pretty narrow to begin with.

Suggestions appreciated.

Joe


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Jmhepworth said:

[CarVac there is room (barely), so you don't have to notch the coupler. Here is a my dry fit with AP retainer removed to show the conduit against the coupler.]

I don't seem to have room for the interstage coupler. The brake line is tight up against the motor tube, and the motor mount fits snug into the body tube, but there is not enough room for the coupler to fit between the brake line and the body tube. If I notch an inch of the coupler, it should work, but will that degrade the strength of the coupler too much? There will still be about an inch not notched to fit inside the body tube. I've also thought about filing the top and bottom of the brake line down to make the outside diameter thinner (flatter) but doubt that will get me enough space to make the interstate coupler loose enough for drag separation. I don't want to flatten the inside diameter because the 3/16 inch brake line is pretty narrow to begin with.

Suggestions appreciated.

Joe


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I had a perfect fit of the interstage coupler before I applied the epoxy - unfortunately, after I had epoxied the MMT in the interstage coupler was too tight and it would stick. I just filed out a 1.5" notch in the interstage coupler for the brakeline to follow and it doesn't degrade anything at all. It is still a rock solid connection that slides apart easily. I would avoid flattening the brakeline as you're likely going to prevent the wires from passing through as you anticipate.

Good luck!

If you have already epoxied in the motor mount, and the hang-up is on the brake line, you could try some selective sanding. If the coupler is close to fitting, maybe fold a piece of 220 grit and work it in between the brake line and wall. It could be that the hang up is just on the edge of the brake line, and once you get past that, the coupler fits. Might be a tough reach, but a little bevel on the brake line could do the trick. I do the beveling beforehand (know that might be water over the bridge) 'cause it also helps with threading the shooter wire by making a bigger opening on the brake line.
View attachment 183091
If the dry fit was good, it might have been some epoxy or something that moved a tad. For future reference, one trick is to insert the inter stage coupler before the epoxy sets up to make sure everything stays aligned. Insert past the brake line, but not touching the aft centering ring of the motor mount. Then pull the coupler out to see if any epoxy is on the walls. Just in case, I wet a paper towel with rubbing alcohol and swab inside the between the motor mount and wall to get out any epoxy before it cures. Then leave the coupler in part way to hold everything in place.

It's more than a little tight. I'm thinking the black fiberglass is thicker than the green. The brake line barely fits between the motor tube and the body tube.

Joe


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Jmhepworth said:

It's more than a little tight. I'm thinking the black fiberglass is thicker than the green. The brake line barely fits between the motor tube and the body tube.

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Joe, Might be a thicker batch. My Wildman Jr is all black tube, and the coupler fit is very snug; so no room for error. I ended up sanding the plastic coating off the brake line and doing quite a bit of dry fitting to get it to work before doing any epoxy.

I had the same issue with my 2 stage shapeshifter with the brake lines. I ended up just flattening it a little with a hammer so that it was oval in shape. That provided enough clearance when it was assembled. I also had a tough time with an aeropac retainer as well. When the wire was installed, it was really tight. I ended up using a slimline retainer instead and have no issues.

Crazyrocket said:

I had the same issue with my 2 stage shapeshifter with the brake lines. I ended up just flattening it a little with a hammer so that it was oval in shape. That provided enough clearance when it was assembled. I also had a tough time with an aeropac retainer as well. When the wire was installed, it was really tight. I ended up using a slimline retainer instead and have no issues.

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I second the use of a slimline instead of the aeropac - that's what I did with my 2-stage shapeshifter also. It's a much better retainer for that sustainer stage - lots of space to get around

Any updates or newly found tips-n-tricks on this endeavor? I'm finally going to start the build on my 2.6" 2-stage Darkstar I purchased 2 Black Saturdays ago

Ordered some brake line....have the 4500 epoxy. Need to round up a second Aeropac. Have a new RRC3 and a RRC2+.

Something I didn't notice discussed or detailed was recovery of the booster. Saw motor ejection mentioned, but really nothing on using a 'chute, rigging, etc.

Think of the interstage coupler as a nose cone for the booster. The booster shock cord attaches to the interstage coupler and the chute is attached as usual.

I need to dig this thing out and up-date it.
I got some improvements.....
Having since been flying 2-stage other projects and doing things a bit different, tonight I'll pull the ole Vindicator out for a re-fit....stay tuned!

Good mental image of interaction....thanks Titan II :wink:

Appreciate it, CJ! Not in any hurry...just getting everything back out to take a look and start the build.