Terrier-Black Brant X

[Funkworks]

For this project, I’ll be following Apogee’s guidelines and videos for Loc’s Terrier-Sandhawk combination, but using a Black Brant X (with 38mm MMT) instead of a Sandhawk.

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-5-Model-Rocket-Kits/Terrier-Sandhawk

My Terrier booster is already built, so this is mostly about assembling the Black Brant X with the necessary electronics to making sure it can be used as a sustainer stage. I already have an EasyMini and will likely get a GPS along the way.

Before starting the Black Brant X itself, I want to build this Ebay.

 

[Funkworks]

Electronics sled is done.

 

[Funkworks]

Glued sled and Kevlar cord to motor mount. I only used carpenter’s glue so far. Seems like I’ll be adding epoxy later.

 

[Funkworks]

Glob of clay to shield off the ejection charge.

 

[Funkworks]

First deviation from the reference instructions: this 3/16th aluminum tube, instead of a paper straw. Working with paper is not enjoyable to me. I also never thing of getting wax paper to help. I'd rather spend $2 at a hobby shop for this tube.

1 foot long. Might have to cut it later. Epoxied in place with HDP 15-min.



Back side of aft ring is at 8 3/8th inch from backside of front ring.

 

[hobie1dog]

Oh man keep the pictures coming, great thread.

 

[Funkworks]

The next step is to make an opening and a cover for the EBay to be accessible once it's inside the rocket. So Apogee includes a paper template to cut out, and to position over the tube, for cutting out an opening at the right place. The right place is 15 inch from the aft end.

Cut-out paper template:



Fifteen inch mark from the aft end of the the tube:



Paper cut out on the tube, ready to guide an X-acto blade, or maybe a pencil first:



The video instructions are for a 14 inch motor tube, and the Apogee website says Loc now delivers an 11 inch motor tube instead, but that's for the Sandhawk. For anyone building the present Sandhawk, the EBay cover should be moved back 3 inches (a 12 inch mark instead of 15) to account for the new 11 inch motor tube.

But I have Loc's Black Brant X instead of a Sandhawk, and the included motor tube is 17 inches. So I don't have to move anything back and can stick to the 15 inch mark of the video instructions. I might even shorten the 17 inch motor tube to 14 inches later on to make more room for the parachute.

 

[Lord Rory Gin]

For this project, I’ll be following Apogee’s guidelines and videos for Loc’s Terrier-Sandhawk combination, but using a Black Brant X (with 38mm MMT) instead of a Sandhawk.

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-5-Model-Rocket-Kits/Terrier-Sandhawk

My Terrier booster is already built, so this is mostly about assembling the Black Brant X with the necessary electronics to making sure it can be used as a sustainer stage. I already have an EasyMini and will likely get a GPS along the way.

Before starting the Black Brant X itself, I want to build this Ebay.

Following... I have the same project on the bench but I put it to rest for now while I work on my paint pile.... I used ordinary JB Weld for the blast plate because of its higher temp resistance. I will be using ordinary paper straws taped together for the wiring tube. The batteries still need to be zip tied secure to the sled but first I need to remove the tiny protection circuit board from the batteries.

Edit: I painted the transition on the Terrier booster just for the fun of it. I want to use the booster on another project as well so I painted it copper.

 

[Lord Rory Gin]

The next step is to make an opening and a cover for the EBay to be accessible once it's inside the rocket. So Apogee includes a paper template to cut out, and to position over the tube, for cutting out an opening at the right place. The right place is 15 inch from the aft end.

Cut-out paper template:

Fifteen inch mark from the aft end of the the tube:

Paper cut out on the tube, ready to guide an X-acto blade, or maybe a pencil first:

The video instructions are for a 14 inch motor tube, and the Apogee website says Loc now delivers an 11 inch motor tube instead, but that's for the Sandhawk. For anyone building the present Sandhawk, the EBay cover should be moved back 3 inches (a 12 inch mark instead of 15) to account for the new 11 inch motor tube.

But I have Loc's Black Brant X instead of a Sandhawk, and the included motor tube is 17 inches. So I don't have to move anything back and can stick to the 15 inch mark of the video instructions. I might even shorten the 17 inch motor tube to 14 inches later on to make more room for the parachute.

One thing to watch out for is to completely seal the ebay from the gases and burned powder that TVM didn't do in his videos. The blow back of burned powder won't do the electronics any good. John Coker uses FunTack (used to put pictures on walls) to seal the edges.

 

[waltr]

One thing to watch out for is to completely seal the ebay from the gases and burned powder that TVM didn't do in his videos. The blow back of burned powder won't do the electronics any good. John Coker uses FunTack (used to put pictures on walls) to seal the edges.

Yes, even more important is to keep the sustainer motor area sealed from the Ebay. If not then the separation charge could cause the Altimeter to think it detected Apogee.

My 2-stage has a simular ebay and the Quantum does sustainer ignition plus chute deploy. The ejection charge could fire if too much pressure reaches the ebay so I ensure the igniter leads are sealed to the tube.

How are you going to setup the electronics?
Do take a lot of time to think this through and do lots of sims.

 

[Funkworks]

One thing to watch out for is to completely seal the ebay from the gases and burned powder that TVM didn't do in his videos. The blow back of burned powder won't do the electronics any good. John Coker uses FunTack (used to put pictures on walls) to seal the edges.

Thanks, I do have FunTack (or some version of it), but I'll have to find or order some "Scotch Spray Mount Repositionable Adhesive". That's simply for sticking the paper pattern on the tube to cut out a cover. The spray would make it easier to make nice straight cuts from the paper pattern.

Yes, even more important is to keep the sustainer motor area sealed from the Ebay. If not then the separation charge could cause the Altimeter to think it detected Apogee.

My 2-stage has a simular ebay and the Quantum does sustainer ignition plus chute deploy. The ejection charge could fire if too much pressure reaches the ebay so I ensure the igniter leads are sealed to the tube.

How are you going to setup the electronics?
Do take a lot of time to think this through and do lots of sims.

My constraints on electronics is to use the EasyMini I already have, and that everything must fit in the rocket. I'll be taking my time browsing through what's available and taking suggestions from people here. No fixed plans yet.

 

[Funkworks]

I couldn't bring myself to pay for "Scotch Spray Mount Repositionable Adhesive" I would only use once. Instead, I just taped four strips of masking tape around the paper pattern to mark the cut line, knowing I'd have to sand the tube later to remove any residue.



Then I used:
- a new X-acto blade to mark the center of the bottom hole (lefthand side on pics),
- a small saw vertically for the short top side cut (righthand side in these pics),
- an aluminum angle and the new X-acto blade at an angle for the 2 long side cuts, and
- the new X-acto blade at an angle for the bottom short side cut (lefthand side in pics).

After the cuts:



Not proud of the long side we see here. Not sure how it happened, but the 3 other cuts are fine.



After some sanding with the cover back on:



Maybe the gap won't show as much after some thick primer and paint. I don't think it will matter in the end.

 

[Funkworks]

Fixed the gap as much as I could and now it's fine.





Sanded inside the sustainer stage to reduce friction with the booster.



Question: when I lift up the sustainer stage, should the plastic cone come with it or should it slide off? I'm wondering just how loose the fit should be.

 

[Rocketclar]

I have a LOC Terrier/Sandhawk that I've flown several times. Mine is snug. I did paint the inside of the ISC with high Temp paint. I also stuff dog barf and top off with some wadding to protect it from sustainer exhaust. I tried to rely on drag separation, but rarely got it (from on-board video). So the wadding was worth it. The videos showed it getting blasted out. Now I have gone to a small separation charge and that works well. I pack 4F around the head of a Firewire's red cap and tape off. I use an Eggtimer Proton in the sustainer.

 

[gdjsky01]

Any progress?

 

[Funkworks]

Any progress?

I'm at the step of sanding the interior back of the tube to allow the booster to slip off. When I lift up the tube, the booster should stay on the ground. Sanding sanding sanding, doesn't slip off. Sanding sanding sanding, still doesn't slip off. Sanding sanding sanding, still doesn't slip off! Sigh! I have to find my finer grades before continuing. They in a box stored underneath other boxes. I have to play Tetris with a room full of stacked boxes to reach them. My tool collection grew much quicker than my tool storage strategy.

 

[waltr]

On the 2-stage I built (used BMS 3" tubes/couples) the ISC does not slide out of sustainer when lifting sustainer.
One reason is the sealed volume inside ISC, a vent hole can help here.

Yes, go with finer grit, I went down to 600 and it slides smoothly but not on its own. After 600 grit I then rubbed in some graphic power (sold for locks). Still doesn't separate on its own.

From what I have read in the forum most 2-stage do not drag separate. They must be forced apart be either a charge (I use 0.4gram) or motor ignition.

You do want the fit to be tight enough that there is no play or wobble between booster and sustainer.
In flight it does separate easily but never from drag.

 

[gdjsky01]

Thank you for the update. IIRC I have seen two or three thin rods from the ISC into the sustainer rear centering ring(s). No shoulder. Just the rods IIRC

 

[Funkworks]

I would normally use Rocketpoxy, but I ran out and decided JB weld will be good enough.

So I epoxied the EBay to the motor mount on both sides.



And I sawed off 3" of the aft motor mount, because I want the back end of the rocket (distance from EBay to exhaust) to be the same as the reference Sandhawk in Apogee's videos.

 

[Funkworks]

I was finally satisfied with the transition-to-sustainer slip fit. It stays on, but slips away if I shake. I'm guessing this will be good enough:

View attachment SlipFitExp.mp4

Play the 6 sec video and tell me what you think. Loose enough? Tight enough?

Edit: People in the Watering Hole say it's good so my next step will be to glue in the MMT.

 

[waltr]

ISC fit looks good. You do not want it too loose since this holds the booster and sustainer in alignment.

A small Separation charge will easily pop them apart.

 

[Funkworks]

Sawed off 1.5 cm of the coupler to make a shelf for the EBay cover.



I also saturated the cover’s edge with CA all around.

 

[Funkworks]

Cut a small shelf (right hand side) for the other end of the hood.
Wrapped epoxy putty around a nut.
Hoping it dries hard enough overnight to keep the nut in place.

The shelf should come off when I unscrew the bolt.

 

[Funkworks]

The nut didn’t stay. New plan:

- Get a new nut, one that isn’t a nylon lock nut. There won’t be as much force when it gets twisted.

- Prepare it for epoxy by filing one side.



- Center it and press it against drilled shelf, remove excess epoxy with tooth pick and waste bolt.

- Clamp gently overnight.



- If there’s epoxy in the nut tomorrow, I’ll clean it out with 1, 2, 3 or more bolts. I have more than I need so might as well use them to clean out epoxy (a tap would be better).

This first page is really long. I hope the thread soon gets a page 2.

 

[gdjsky01]

I have had good luck clean the nut with rubbing alcohol then using epoxy clay or even thicken epoxy over it.
I always rub petroleum jelly in the threads of the nut and then thread in a bolt/screw. That way no adhesive gets in the threads of the nut and yet I don't worry about extracting the fastener.

 

[Funkworks]

Rubbing alcohol, petroleum jelly and epoxy clay. 3 things I don’t have at hand right now but should find by the end of the week.

 

[gdjsky01]

Save yourself some dough. Apogee, bless Tim's little heart, charges a mint

https://www.amazon.com/gp/product/B07MKLMMTL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Let me say, put the lube on the screw/bolt threads. Put the clay all over the nut and press into whatever the nut is mounted to. Thread the screw/bolt into the nut and have it break though the clay holding the nut. Let the epoxy set. Back out the screw/bolt (which should be fine because of the lube.)

 

[Funkworks]

- If there’s epoxy in the nut tomorrow...

There wasn't any epoxy in the nut and it stayed while I twisted in a bolt. So I carelfully filed the 6 sides and added epoxy (JB weld) all around. I'm confident this will do the trick.



To recap, here's what did not work:

- A 3-year old lump of epoxy clay
- A nylon inserted lock lut

And here's what worked:

- Filing a SS nut on one face and using epoxy to bond it on the cardboard carefully to prevent filing the hole.
- Once dry, ensuring the threads were clear by twisting a bolt in and out a few times.
- Carefully filing the 6 sides of the nut and spreading epopxy all around.

Let me say, put the lube on the screw/bolt threads. Put the clay all over the nut and press into whatever the nut is mounted to. Thread the screw/bolt into the nut and have it break though the clay holding the nut. Let the epoxy set. Back out the screw/bolt (which should be fine because of the lube.)

That's probably my next backup plan but it looks like I won't have to go there.

 

[Funkworks]

Done with the electronics bay and hood.



Next, I'll be preparing it to be painted.

 

[Funkworks]

Tamiya puttied the spirals and sanded.



Will be working on fins next. Minimal sanding.

Something wrong with this thread. First page is way too long.