Four inch BSD Thor clone

So since it does not appear that BSD is ever going to get back into business I thought it time to take matters into my own hands. This is a kit I've wanted for years but BSD went out of business long before I started making L2 rockets. Something about the look of this one, the whistle of the fins on the ascent and just how the decals made the rocket look a lot larger than it really is are all things that just appealed to me. So with the help of some birthday money I made the journey to Red Arrow Hobbies and bought all the parts needed...well not really. Haven't decided on motor retention and all the hardware for the e-bay. Here are the high points of this coming build:

- Zipperless. Not my style usually but a lot of people made it zipperless so I am just going to follow suit.
- Alts. Not sure which alts I am going to put in here but it'll probably be the Hialt45k and Adept22 I have.
- Connection through the e-bay. This I will only refer to as the "Burns Fillament" for the time being. More on this later.
- First flight. As of now will be a Loki J396 SF. A Loki motor in a Thor rocket? Hmmmmm....

-Dave

View attachment thor_4.rkt

It's a little rough at this point...more tweaking to come.

FWIW, Binder Design sells all of the proper components, like airframes, motor tubing, nosecones that all match the OEM specs of this kit.

Binder Design said:

FWIW, Binder Design sells all of the proper components, like airframes, motor tubing, nosecones that all match the OEM specs of this kit.

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That's good to know for those following this thread and who want to do the same. Just for reference I have no intention of making this an exact clone but am using these materials for merely personal preference.

Binder Design said:

FWIW, Binder Design sells all of the proper components, like airframes, motor tubing, nosecones that all match the OEM specs of this kit.

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You have my attention.

o1d_dude said:

You have my attention.

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It's never been a secret that Binder Design and BSD Rocketry used the same suppliers and tubing specs. Except for recently I've gone to HD couplers that are thicker and longer, the stuff is all the same.

The 3 inch BSD kits used these great translucent nose cones that are perfect for night flights (R.W.W DIST.). Are these available from Binder? Is there a similar nose cone in a 4 inch size? They distribute the lighting from nightbows and other LED's perfectly.

Nice Dave. I always wanted a Thor too. Wondered about building one a few times - someday... Watching with interest.

terryg said:

The 3 inch BSD kits used these great translucent nose cones that are perfect for night flights (R.W.W DIST.). Are these available from Binder? Is there a similar nose cone in a 4 inch size? They distribute the lighting from nightbows and other LED's perfectly.

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We have the RWW cones in 3" and 4" but they are now white plastic.

The one thing I have not found is where exactly to place some of the decals. The fins are pretty obvious but the ones that go all the way around the body along with the "THOR" decal I am unsure of. I'm sure I can figure something out on my own but am curious as to what the original design locations were.

I'm also curious if anyone knows whether or not rounding over the leading edge of the forward fins and/or rounding over the trailing edge of the rear fins will diminish the whistling effect of the split fins. I doubt it would but it would be nice to hear from someone with actual experience.

Round the leading edge, leave the tail edge square as in between the two fins, speed of travel has an awful lot to do with it too. To fast and little to no whistle.

The fin thickness also plays a part. My Thor with 1/4 inch plywood fins whistles, while my friend's Thor with G10 fins does not.

This is all something that a lot of people already do BUT in case there is someone reading this that has never cut tubing before here's how I do it...

First I have to mark out where I want the cut with a simple pipe clamp. Tightened down just enough to be snug but not damage the tube:



If you have Dremel this is a must have bit. Cuts phenolic like a dream. Just need to have patience and a steady hand - go slow!



So it looks a little rough...



That's when I square it up on the table belt sander.



A little touch up with some 120 by hand and I'd say it looks pretty daggum good:




I have a few tube cuts to do on this project and all of them will be done this way.

terryg said:

The fin thickness also plays a part. My Thor with 1/4 inch plywood fins whistles, while my friend's Thor with G10 fins does not.

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I figured as much so in all the threads and rocksim files I found on it almost all of them listed 3/16 birch ply as the fin material so that's what I bought.

Not to start a glue war here but I will be using wood glue where ever possible. You're not talking me out of it.



On the back of the bag of t-nults I find this...California, you're weird.



So motor retention. Yes, FOUR t-nuts because why not?



So since I've had these little boogers pop-out I am electing to make little tabs to glue them in...Remember that bit I showed you earlier? That's how I cut out these little tabs and then grooved out a layer of ply so the tabs will sit flush on the rear centering ring.



And yes, I am aware that I am blocking the t-nut holes. Once the glue dries I will drill out pilot holes from the open end of the t-nuts and widen them out from there.



Those little clamps are cheap and VERY handy. If you haven't purchased a box get some. As you can see here it makes items like this much easier.

First dry-stack. Barely fits in my basement hallway. Sheez this thing is going to be tall. 😄

I tacked the fins in place with some CA and on to the next step.

So to do the internal fillets meet Mr. Spoon taped to Mr. Dowel...



Looks a little messy in there but it'll hold.



Topside looks a lot better.




I make the most boring build threads ever. Look at all those replies haha.

I make the most boring build threads ever. Look at all those replies haha.[/QUOTE]

Obligatory reply.

Oh and yikes that is tall.

Igotnothing said:

Oh and yikes that is tall.

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Eh...not really, it's roughly 80" tall which puts it at 6'8" or so if I am doing my math right.

Nice looking bird there, Dave! You got my attention! Don't forget to give us an all up weight on it! Seriously nice looking rocket (did I say that twice?)

I have difficulty moving mine around the house. I never seem to remember that it comes apart until I hit something!

Looks good so far. I wish I had done a better job on mine, but even with its flaws, it flys and whistles....

I ~need~ to build one of these.

Looks great and I look forward to seeing you fly this!

I have often thought about making one of these myself, but the space (or lack thereof) is the big issue.

etoyoc said:

Looks great and I look forward to seeing you fly this!

I have often thought about making one of these myself, but the space (or lack thereof) is the big issue.

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There's always the option of down-scaling.

A 38mm BT version would be way cool...

I wouldn't mind doing a 3" version. Looking around I see that the LOC Athena is darn close and I actually like 29mm. I may have to look closer.

I was thinking one of the Binder Design 4" kits (Tyrannosaur...hint hint) might be a great set of bones from which to make a THOR.

Modify the forward set of fins...loose the finlets...

Time to glue on the rear centering ring...put the screws in and tape over them to prevent glue from getting down the t-nuts..


Drilled out the holes for the baffle/zipperless assembly



Just checking the other one making sure that after drilling holes through both that when rotated the holes do not line up with each other.



And of course with all the tubing I needed to cut my Dremel battery decided it was tired. One of these days I'll spring for a corded Dremel. But my cheapo hobby saw from Ace Hardware came to the rescue.

This is the inside of my e-bay. Yes I cut a coupler to length and then cut it longitudinally...This piece is then glued to the inside of the coupler being used the coupler. This will make more sense later on.



Then, every piece of bulkhead that is exposed to BP charges is coated with a light layer of epoxy.



This is the strap that will go through the baffle/zipperless assembly. This strap is what I will connect the drogue part of the recovery train to. Again, this wil make more sense as the build progresses.

Ladies and gentlemen, I present the "Burns Fillament"



The thought here is to eliminate the standard practice of utilizing 2 threaded rods and 2 U bolts for connecting the recovery train to the electronics bay. That standard method seems like overkill and overly heavy to me. Here, I would run my quick-links in the loops created by the wire. After careful consideration there are a number of issues with this approach. First, the wire clamps have pointy bolts that stick out and stand a good chance of snagging important items like the cord and parachutes. Even with 1/16" wire rope you can only bend it in a loop so far so at least 6 or 7 inches of wire rope is sticking into the parachute bays which seems that it would make packing chutes a challenge. Lastly, securing the bulkheads so they are snug against the coupler is difficult.

So if anyone has any ideas to impliment this thought better I'd like to hear it otherwise I will be doing something a little more traditional.

-Dave

DAllen said:

Ladies and gentlemen, I present the "Burns Fillament"

View attachment 258350

The thought here is to eliminate the standard practice of utilizing 2 threaded rods and 2 U bolts for connecting the recovery train to the electronics bay. That standard method seems like overkill and overly heavy to me. Here, I would run my quick-links in the loops created by the wire. After careful consideration there are a number of issues with this approach. First, the wire clamps have pointy bolts that stick out and stand a good chance of snagging important items like the cord and parachutes. Even with 1/16" wire rope you can only bend it in a loop so far so at least 6 or 7 inches of wire rope is sticking into the parachute bays which seems that it would make packing chutes a challenge. Lastly, securing the bulkheads so they are snug against the coupler is difficult.

So if anyone has any ideas to impliment this thought better I'd like to hear it otherwise I will be doing something a little more traditional.

-Dave

Click to expand...

You can try and go with a single all thread through the middle with a coupling nut and short thread eye bolt to the coupling nut.

Single piece of 1/4" aluminum allthread through the middle, wing nuts on both ends. Drill two holes and make a Kevlar loop. Super lightweight, easy.