Mach 1 Black Hole BT-60

My next project will be a Mach 1 Black Hole BT-60 setup for dual deploy with an Eggtimer Quark and room for an Eggfinder Mini if I really want to push it. I also ordered a nosecone bay and electronics bay from SMT Designs and was told the parts should be finished and ready to ship by early next week. I was planning on flying this kit mostly on the hobbyline reloads. Looking through some different sims, it seems like this kit was made for the 29/40-120 case. Using Steve's Open Rocket File, an E-16 motor shows 872 ft while the G-138 reaches 3421ft at a max velocity of 728 mph. Assuming the stock plastic nosecone survives mach speeds, an I-120 would carry it to 5231ft at 953 mph.

Obviously, I'll have to tweak the Open Rocket file as I build my kit with the components I have, but those numbers give me a good place to start. Right away, I know I'll use 1010 rail buttons instead of the mini buttons provided in the kit because it looks like I'll need the full 6ft rail for a stable launch on an E motor.

Sounds like a real fun one! Gorgious kit. Good luck!

Thanks, it should be a fun build. I was planning to start building the motor mount yesterday, but took advantage of the sunshine making a 30 degree day quite comfortable for Winter. Everything else needed for this build has been shipped, so I should be able to start on my next day off work.

My mailbox was stuffed full of packages this afternoon. I received a big envelope from Eggtimer and a box from SMT Designs, both a day earlier than the tracking predicted.

Maybe I will get a new soldering station for Christmas to work on these kits. I have some PTO next month so I might wait until then to start on the electronics. My other option is to work on them during downtime at work. Of course, if we get a call I have to stop right where I'm at.

In the meantime, there will be plenty of work on this rocket. I'm going to start assembling the electronics bays and the nosecone adapter to accept the tracker sled.

These are the parts for the nosecone sled for an Eggfinder Mini by SMT Designs. Steve supplies a very complete kit. The 3D printed parts have threaded metal fittings and he supplies all of the hardware needed for assembly, even some short lengths of wire for the switch and a JST connector for the battery.


The nosecone is the stock plastic BT-60 nosecone included with the Black Hole kit. The shoulder will be cut off and the adapter from SMT secured in place with epoxy.

Steve has general instructions for his electronic bay components on his site. Once I held the parts in my hand, it was easy to see how everything fits together.

The nosecone cap has 2 holes and a channel to thread the kevlar cord through to make the recovery loop.



You will also see a place for 3 screws that hold this cap to the body of the sled and a 4th screw that activates the switch built into the bulkhead.



The last pictures are the rest of the sled screwed together with the battery holder underneath the sled. I wanted to make sure I had enough room in my nosecone before I chop the shoulder off.

Here is a tease of the SMT Designs Hybrid Electronics Bay for the Mach 1 BT-60 tubes. This one fits in the 6.5" coupler, but I think Mach 1 is supplying 7" couplers now, which is also an option from SMT Designs.

The instructions for the bay on the Mach 1 site didn't format quite right when viewed on my tablet. I'll have to print them out so the captions appear with right photo. Also, I might just be tired from work this evening, but I had to look at the instructions and fit parts a few times before it "clicked" with me. Once I solder the connectors on the wires and get the switches installed on both of these bays, I will try and get pictures of each step.

Nate, I have the same set-up! Same rocket, SMT parts and all.
I’m starting my build of it all just after Christmas.
This is going to be a great fun time!

That's great that we are building the same kit and setup!

Black Hole BT 60 MD a couple of weeks ago also. Built and first coat of paint is on. Used the Aeropack retainer glued into the coupler. Made it motor eject. My 1080 case arrived today, but with the MD retainer I have to use the adapter system with the floating enclosure. My question is will the SMT NC sled work as a deployment setup also? Then I could use a full 1080 reload or a plugged motor and eject the nose to pull out the chute.

The SMT NC bay does not have any means for deployment as I see it. I would like to be able to use an Eggfinder TRS in it eventually.

Just looking at the parts, the first thing I would try is removing one of the screws from the end cap side by the switch and pass the ematch lead through the hole already drilled. Use a piece of a rubber glove and tape to hold your BP charge. You would also want to rig some sort of switch coming out the side of the nosecone or shoulder so you can arm it with the nosecone in place.

I am also wondering if some of the other components SMT offers could be used with the NC sled to allow for his 2 post deployment system and switche used in the other bays. I have some of the parts on hand, but haven't tried to mate the BT60 bay parts to the NC sled yet.

I sent SMT an email late last night asking about a sled with deployment to go in a BT 60 NC. Have not heard back, when I do I will let you know what he says.

Thanks! It will be nice to hear his ideas too.

As the NC Sled is currently designed, it won’t. But... if I know Steve, he may have a brainstorm and have a solution. But with that much motor, you’ll want the NC sled for a tracker for sure.

Today, I finished assembling the nosecone and payload electronics bays. The shoulder of the nosecone was chopped off and the SMT adapter was glued into place with Maxi Cure. The nosecone, adapter, and sled together weigh 95g. I haven't assembled my Eggfinder mini or purchased the battery yet.

What NC did you use?

That is the stock plastic nosecone from the kit. I think it is an Estes BT-60. I also ordered a Starlight BT-60 MD, but with the LOC nosecone thinking it might be more sturdy with larger motors. That kit hasn't arrived yet, so I can't compare them.

smt sent email stating out till new year. Will keep you informed of what his thoughts are on NC ejection charge gear.

This project is still alive, just slow going. Today, I finished the motor mount and drilled the holes for the rail buttons in the booster.

I had planned on using the little nut holders from SMT Designs for the rail buttons, but I didn't plan that far ahead when I secured the motor retainer with JB weld. I should have left it and the aft centering ring off until the nut holders and motor mount were secured in place. Oh well, they were for extra insurance anyway. Once painted, the bolts for the rail buttons should grab and thread into place anyway.

Next step, round or bevel the fins and make this thing look like a rocket.

I made a little more progress today. The motor mount was glued into the booster and I rounded all the fin edges by hand. I also ordered the router table attachment for my Dremel tool so I can build a jig to shape the fins and get more consistent results easier than I can by hand for future builds.

hey Nate, looks great. You can remove the epoxy very easy witha bit of heat, The glue will become soft, you can scrape it off and remove the centering rings. then just sand as normal and can reglue after install.

I also ordered the 38mm NC with metal tip from wildman, I used the sleeve that came with the Mach NC and it fits perfect.

Thanks! The rail buttons thread in and hold far better than I thought they would without any backing nuts in the thin fiberglass. I don't think I need to remove the retainer or aft centering ring.

I have this whole week off work, so I hope to make some quicker progress on this build. I should be able to get the 6 fins attached and fillets on. I would also like to start soldering the electronics for this project towards the end of the week. My wife isn't off the entire time I am, but she has a few extra days off too. I'll need her help to keep an eye on our curious 3 yr old son when I have small parts and a hot iron out.

From the loks of your MMT it is the 29mm version. I did mine with the stuffer tube and is the 38mm one. the nuts might have held well going thru both airframe and stuffer but I still put nuts on the inside.

NateB said:

Thanks! The rail buttons thread in and hold far better than I thought they would without any backing nuts in the thin fiberglass. I don't think I need to remove the retainer or aft centering ring.

I have this whole week off work, so I hope to make some quicker progress on this build. I should be able to get the 6 fins attached and fillets on. I would also like to start soldering the electronics for this project towards the end of the week. My wife isn't off the entire time I am, but she has a few extra days off too. I'll need her help to keep an eye on our curious 3 yr old son when I have small parts and a hot iron out.

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For fiberglass rockets that size I don’t use nuts on the inside. I just thread the rail button screw directly into the body tube.

Steve Shannon said:

For fiberglass rockets that size I don’t use nuts on the inside. I just thread the rail button screw directly into the body tube.

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I have done the same thing as Steve for years. You can even put a drop of CA on the screw threads and just screw into the FG tube

Are you doing this with the thin wall stuff also?

The lower set of fins are in place with the epoxy curing. Rather than inject internal filets, I buttered the fin root and doubled dipped to build a good bead of epoxy on the motor mount and fin root.

I'm going skiing tomorrow, so I probably won't work on the upper set of fins until Friday. We might get a snow storm Saturday followed by a single digit highs on Sunday. Those should be good days to stay indoors and assemble the electronics.

Got a little hangar rash before the build was complete. My dog ran into me when I was moving the rocket off the kitchen table to a safe place for the night. I dropped it on tile floor and just chipped one fin. Good news, the fin didn't break off or get misaligned. A few fibers of the G10 started to fray, so I wicked some thin CA into the edge and smoothed everything out with sandpaper.

The upper set of fins are now curing. All that is left of the build now is add the external fillets and drill holes for shear pins, vents, and the arming screw.