BSD 38 Special DD build thread

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hazegry

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Ok guys this is my first HPR build it is going to be my L1 and L2 rocket.
The L1 cert flight is going to be on a loki H-100-sf spitfire with a H-144-lw as a back up motor in case it doesn't qual for some reason. The L2 is going to be on a J-528-LW. Obviously I am not going to build this stock I am going to glass the tube and use 2 30" chutes for recovery and I will be adding an alt bay. The first probable I ran into is that the payload section is to small I could just order a larger one but I have decided to glue the payload sec to the body tube and then fiberglass, after that I will cut the tube farther down for the ebay. the first thing I am going to do is build the alt bay due to its small size I am going to let the ejection charges float if you have a better idea I would like to hear it. The alt bay will be connected to the payload bay with plastic rivets and it will pop the NC off for deployment of the chute using the charge to help the 2 cutes out of the tube.

well now that we have gotten my plans posted lets get to my first question. this kit has tube couplers to strengthen the body tube. The couplers are supposed to be put in after the MMT and fins have been attached. I cant do this before I glass the tube but I need to use a coupler to glue the payload bay to the body tube. So how should I go with this should I build the mmt dry fit it then install the couplers and remove the MMT and fiberglass with balloons or something installed in the end to add strength for when I use the shrink wrap tape with the fiberglass. or should I just use balloons or something in the ends fiberglass then install the couplers after I cut the tube for the alt bay? kinda at a loss as to how to go about it. I will post pics later I am on my laptop right now
 
I have a 54 special. The way the couplers fit is set up so that when you have the MMT in, the couplers start at the top CR and if you put the number in they tell you to, you end up with just the right amount left to connect the next tube. So keep that in mind when you change things, the directions will be off after that and you might have to adapt the rocket parts to make it work. If I'm reading your description right, it sounds okay. I didn't glass mine, I don't think it's nessicary for what I am up too.

Unfortunately, the motor had an issue on the first flight and the lower section is burned out from the inside. The motor threw flames from both ends. So I'm rebuilding it with a few changes. Good rocket though, nice quality parts.
 
Ok I got the alt bay built. I decided to not install the couplers since I am glassing this one. I am going to glue the alt bay in the upper section and use NC eject.My motors should be here tomorrow and I will start building the fin can do I peel the mmt tube before I epoxy the fins on or do I just sand where the fins are going to go?
 
Ok I got the alt bay built. I decided to not install the couplers since I am glassing this one. I am going to glue the alt bay in the upper section and use NC eject.My motors should be here tomorrow and I will start building the fin can do I peel the mmt tube before I epoxy the fins on or do I just sand where the fins are going to go?

you can just sand it down...i marked the outline of the root chord of my fin, then traced over it with an x-acto and peeled the top layer off, makes for a nice little seat for the fins, also lines them up nicely. but sanding should work fine as well.
 
pics of the build so far sorry my camera is crappy and I am not that good with it either.

IMGP0360.jpg


IMGP0351.jpg


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Hot stuff! I'm getting one for Christmas (non G10 though), and seeing this makes me even more exited! :D

Is it single or duel deploy?
 
normally the 38 is single deploy but I added an alt bay and I am making it a dd.
 
Looking great so far! I just ordered a 38 Special for my L1 attempt..Will be watching your build closely- so, don't mess up! :p
Am thinking too to make mine DD..not sure yet..Is there a way to make it so the ALT bay can be removed and flown single deployment using motor ejection?
 
Panther you can do it that way I chose to glue my alt bay in but even if you did glue yours in you could still do single deploy. Just dont load and charges to your alt or even put the alt in. or you can just remove the upper bay and fly on the lower tube. I might have to do that for mine since I am coming up short on my alt funds.
 
I epoxy my alt bays half way into the upper air frame. If you want to fly DD you have the option, if you want to fly single deploy then you have two options. AS Hazegry suggested fly on the lower section only for smaller motors, but if flying bigger motors then you can use those snap rivets.
Make three holes in your av bay for the rivets. That way when you're not using the rivets for single deploy (motor ejection) the three smaller holes are perfect for av bay venting if using barometric alts. This is for a 38mm rocket obviously. If going for larger airframe then remember to make a bigger hole besides the 3 small ones.

Brent
 
I got my heat shrink tape in today so sat I will be glassing my rocket its supposed to be between 52 and 59 degrees sat.
 
well I am sitting here waiting for the resin to cure. I had to bring it inside due to the lower than expected temps. I will let you guys know how it goes but so far its looking good.
 
Just got my 38 Special in Saturday! :) Was really kind of surprised when I checked the FedEx tracking it would be delivered on a Saturday!:surprised:

This will make the biggest rocket build to date for me, in both size and propulsion! ;) Needed to move the build out to the kitchen to have a bit more room..lol..Will actually start applying epoxy to it Sunday after my trip to Lowes..Here it has the tubes dry fitted and nose cone on..Tall one! :D

BTW, I took the lazy mans way out, I got the pre slotted option :)

38Special001.jpg
 
Cool! You got the pre-slot too, huh Jon? :lol:

I'm gonna start building mine too soon. Are you going to use the motor retention option?
 
Cool! You got the pre-slot too, huh Jon? :lol:
Yep, I be lazy! ;) Am thinking that I will go with rail buttons instead of a launch lug as well..Will have to see..If I do that I will need to order some ..lol..

I'm gonna start building mine too soon. Are you going to use the motor retention option?

You betcha! Don't want my 38MM casing to come back ballistic and risk thumpin someone in the noggen ,PLUS they are a bit pricey as well...lol..
 
you should have gotten some launch lugs with your kit. I am thinking about getting the whiplash in a few days. its ether get the whiplash or get my alt what to do what to do.
 
Rail buttons are included! They're in one of the little bags. ;)

I think I'm going to give mine both launch lugs and rail buttons, so it can use whatever is available at the launch (if pads are provided).
 
Bzzzzt...the sound of a light coming on! So that's what those round black plastic thingies are! :rotflol:

Now, for the next 'duh' question: How to attach? Drill a small hole in the bt, use the long thingy on the inside of the BT to snap into the round thingy on the outside?

rail button.jpg
 
Anyways, got a little bit done on my 38 Special..Man, I am slow...lol..Got the motor mount assembled and motor retention installed..Here are a couple of pictures:

Motor mount:
38Special002.jpg


Motor retention:
38Special003.jpg
 
Bzzzzt...the sound of a light coming on! So that's what those round black plastic thingies are! :rotflol:

Now, for the next 'duh' question: How to attach? Drill a small hole in the bt, use the long thingy on the inside of the BT to snap into the round thingy on the outside?

The parts you have there are not used together. One is the rail button, the other is a plastic rivet. The rail buttons are attached with screws that come in the same bag. There is a little article on the BSD website that describes how to use them. I think my 54 Special came with a supplemental instruction sheet with the same information. Basically, drill a 1/8" hole then put some epoxy on the bottom of the button and in the hole. Screw the button to the airframe. The screw will cut it's own threads in the cardboard and the epoxy will take care of the rest. Worked great on 2 birds for me so far.

I'm not sure what the plastic rivets are for in the 38 Special. For the 54, they are used to connect the electronics bay to the body tubes and couplers.

Nice looking build pics so far. I think you'll like the BSD kit, I found mine to be very nice.
 
Another enlightening moment-minus the sound effects this time! Now I know how to attach those round black thingies commonly referred to as 'rail buttons' :D And also just figured out how to sim dual deployment in RockSim on this bad boy! So, tonight has been a real learning one- I love it! :)

I think I have about 95% convinced myself to go ahead and make this one DD- boy nothing like jumping in uncharted waters head first! So this is how I was thinking it should be configured:

The payload/e-bay will have a bulkhead at the aft end where the shock cord from the main tube is attached with the drouge attached to it..The electronics will be mounted on that bulkhead and then the 2nd bulkhead mounted on top of that with attach point for the cord with the main chute which attaches to the nose cone which will be attached using shear pins..

I think I got it all...Did I miss anything, wrong sequence? The payload bay tube is 13.5" in length, nose cone shoulder depth is 3.5" and the aft bulkhead is like 1" into the aft of the tube leaving me about 8.5" to play with..Is that enough room for a small altimeter and such leaving room for the main chute and whatever is used to pop the nosecone to deploy the main?


While I am thinking of it: Do they make altimeters that initiate these events? Deploy drouge at apogee, then deploy main at set altitude- guess it would be a 2 event one?

If this is all like 'well, duh' , forgive me as this is my first HPR rocket and I want to get it right :D
Thanks!
 
what I did was epoxy the payload bay to the airframe then fg the entire thing. I then cut it about 2' above the center and epoxied in a LOC 3" alt bay for my alt. if you want to do that I would suggest buying the 54 special I think this would have been much easier if I had gone with the 54.
 
Another enlightening moment-minus the sound effects this time! Now I know how to attach those round black thingies commonly referred to as 'rail buttons' :D And also just figured out how to sim dual deployment in RockSim on this bad boy! So, tonight has been a real learning one- I love it! :)

I think I have about 95% convinced myself to go ahead and make this one DD- boy nothing like jumping in uncharted waters head first! So this is how I was thinking it should be configured:

The payload/e-bay will have a bulkhead at the aft end where the shock cord from the main tube is attached with the drouge attached to it..The electronics will be mounted on that bulkhead and then the 2nd bulkhead mounted on top of that with attach point for the cord with the main chute which attaches to the nose cone which will be attached using shear pins..

I think I got it all...Did I miss anything, wrong sequence? The payload bay tube is 13.5" in length, nose cone shoulder depth is 3.5" and the aft bulkhead is like 1" into the aft of the tube leaving me about 8.5" to play with..Is that enough room for a small altimeter and such leaving room for the main chute and whatever is used to pop the nosecone to deploy the main?


While I am thinking of it: Do they make altimeters that initiate these events? Deploy drouge at apogee, then deploy main at set altitude- guess it would be a 2 event one?

If this is all like 'well, duh' , forgive me as this is my first HPR rocket and I want to get it right :D
Thanks!


You've got the basic idea. My suggestion is that you go look at various other projects people have posted build threads on and get ideas. You will find a hundred different ways to do the same thing, but you can see what people did, and how it worked. Then you can make informed decisions on your project. Take a step back, and think it out, or draw it on paper/Rocksim. I'm not using shear pins at the moment. I am just using friction fit to make sure the nose cone won't come out if I invert it and shake. It's still loose enough that the deployment charge will pop it out though.

For electronics, most altimeters that support deployment will work for DD. I own a Perfectlite MAWD. I have yet to have a successful flight with it as my single attempt had a motor failure that has me rebuilding the rocket. That has nothing to do with the altimeter though. I have heard good things about the Missleworks RRC2-Mini and many others. The Support and Recovery forum here on TRF has many postings about altimeters.

First HPR? So no L1 yet? You're in for a fun ride. I did my L1 just a few months ago. I suggest saving DD flights for after the L1 cert, as it's a lot more things to do wrong, like forgetting to arm the electronics. :rolleyes: But you can build your rocket to support DD and fly with motor ejection for the first flight. Just put the main chute in the drogue compartment and make sure the nose cone is nice and tight.

For an electronics bay, you can be really simple with a body tube and some bulkheads. You can also be more complex with threaded rods and such. It depends on you. I'm building my own with a heavy duty coupler from BSD. That gives me 7" length to work in. I then bought 2 bulkheads from them that fit inside a coupler and another that fits the body tube. The coupler sized ones don't fit the heavy duty coupler, but the sander fixed that. I then epoxyed in one of the coupler sized bulkheads with a U-Bolt (overkill) and 2 1/4" threaded rods w/nuts (also overkill). The rods connect to a stacked set of bulkheads. One fits in the coupler, the other fits the body tube, so it makes a lid for the other end. It also has a U-Bolt and holes for the threaded rods. Slide the "lid" on the rods, tighten some wingnuts, and it's all sealed up. Now I need to cut some fiberglass I got to mount the altimeter to, and set up power and vent holes and it will be ready to fly. I can post pics of the construction tomorrow if you would like to see them, but I got the basic idea here: https://www.vatsaas.org/rtv/construction/avbay/avbay.aspx

To fly DD you will also need e-matches, black powder (or pyrodex, but that has it's own set of problems, so look into it before using pryodex), some kind of charge containers, and a power switch for your altimeter (or twisting wires works). Your HPR motor vendor should be able to get e-matches for you.
 
Jon, what speed of epoxy are you using?

I am using 5 minute epoxy right now...Too fast, I know..No one around here has 15 or 30 minute epoxy except in those tiny syringes:( I would probably need like 10 of those to finish this rocket!:eek: ..Just ordered some 30 minute epoxy online few minutes ago..The same quantity as 8 of those little syringe things for like $8 :)
 
Thanks for the in ttabbal! :) Will need to do some more research on altimeters..Am leaning towards either a MAWD or the HA45 unit..

Since either unit will fit inside a BT50 I was thinking of epoxying one to the side of the payload bay(with the vent hole) and mounting the unit on a piece of ply that would slide down 2 4" long all threads, and a cap secured using the all threads and locking washers and nuts..Charge canister would be mounted on the top of that..Of course now I need to figure out how to wire it so it sets off the charge to deploy the drouge ..lol

Idea: The charge does not necassarily HAVE to be BELOW the drouge does it? Just as long as it pressurizes the tube causing it to seperate, correct? So I COULD rig the charge to the bottome of the payload bay's bottom bulkhead, correct?It should work, as it is to go off at apogee where the rocket is to start pointing DOWN and what was down is now up..
 
Thanks for the in ttabbal! :) Will need to do some more research on altimeters..Am leaning towards either a MAWD or the HA45 unit..

Since either unit will fit inside a BT50 I was thinking of epoxying one to the side of the payload bay(with the vent hole) and mounting the unit on a piece of ply that would slide down 2 4" long all threads, and a cap secured using the all threads and locking washers and nuts..Charge canister would be mounted on the top of that..Of course now I need to figure out how to wire it so it sets off the charge to deploy the drouge ..lol

Idea: The charge does not necassarily HAVE to be BELOW the drouge does it? Just as long as it pressurizes the tube causing it to seperate, correct? So I COULD rig the charge to the bottome of the payload bay's bottom bulkhead, correct?It should work, as it is to go off at apogee where the rocket is to start pointing DOWN and what was down is now up..

I've seen a few DD flights, but I'm not an expert. All the ones I saw fly had the charge above the drogue chute at the top of the compartment. Separating the rocket is the important part, you just don't want it coming in ballistic. I see about 60% fly with no drogue, just separated to give it some drag.
 
I am sure we all go thru this at one time or another: You have a project you're working on and yet can not get motivated to do any more on it even tho every time you look at it you say 'I should be doing something with this'..That's what this last week has been like for me..But anyway...
Well, taking a couple of baby steps..Got some done on my 38 Special this morning..Got my supply of 30-minute epoxy in so here is the major accomplishment for the day: I epoxied the motor mount in and the 3 tube couplers from the fore end of the MMT..Found that I am an absolute KLUTZ, but I knew that already!:rotflol:No major mishaps, just uncoordinatedness..Here are some pictures:
BT standing by table(oh look I installed the leader strap too!)And you can see the highly technical method I use for mixing my epoxy! :p
38Special004.jpg

Looking into tube to show couplers-sorry for the fuzziness..
38Special005.jpg

And the aft end
38Special006.jpg
 
looks good whats the largest motor you are planing on sending it up with? I fiberglassed mine and made it dd due to the fact its going up on a loki J528
 
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