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Booster Rocket Separation - Ground Test

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DMcCauley

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Completed first successful ground test of our booster ground separation. Works beautifully and the mounting is rock solid.
Plan to launch probably in winter / spring 2009. Main motor will be M650W with (2) K550W boosters. The K550W's will be airstarted immediately upon upward motion of the rocket.

See the video here:

http://www.youtube.com/watch?v=stK7WMMFUrk

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sylvie369

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Beautiful. Love the slow motion.

I'd sure like to see that kind of video of the actual flight. Better yet, how about some kind of onboard video from above?
 

Len B

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Completed first successful ground test of our booster ground separation. Works beautifully and the mounting is rock solid.
Plan to launch probably in winter / spring 2009. Main motor will be M650W with (2) K550W boosters. The K550W's will be airstarted immediately upon upward motion of the rocket.

See the video here:

http://www.youtube.com/watch?v=stK7WMMFUrk

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Nice job! Is that your own invention or is it a version of the Booster Dropper? Sorry if I missed a thread around here somewhere. It sure worked well.
LenB
 

DMcCauley

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Nice job! Is that your own invention or is it a version of the Booster Dropper? Sorry if I missed a thread around here somewhere. It sure worked well.
LenB
Thanks.

Yes, this is my design. I did look at the booster dropper design initially, but decided it wasn't the best way for us to go on this rocket. The new design is rock solid and extremely simple. The upper explosive carrier utilizes a rod which is locked into place with a shear pin, and the bottom is a hinge which sits on a 1/2" diameter aluminum rod. When it rotates, the hinge just disengages and booster falls.
 

leegscott

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Looks great and sounds really simple! Do you have any sketches of the design?
 

DMcCauley

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Gee that design looks similar to this one.
Actually, if you go back reread the following post, you'll see my drawings for this design were released before you posted your PDF drawings as well as using a lower pivot hinge for connecting the boosters at the base, so "no", i didn't copy your drawings as you are implying.

http://www.rocketryforum.com/showthread.php?t=932

Tend we forget . . .

Plus, we both based our design on what Troj already did so its quite likely they would be similar.
 
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kandsrockets

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Actually, if you go back reread the following post, you'll see my drawings for this design were released before you posted your PDF drawings as well as using a lower pivot hinge for connecting the boosters at the base, so "no", i didn't copy your drawings as you are implying.

http://www.rocketryforum.com/showthread.php?t=932

Tend we forget . . .

Plus, we both based our design on what Troj already did so its quite likely they would be similar.
You never posted your bottom design just the upper design that was based on Kevin's design so do not say it is your design. Give credit to where your idea came from. And yes my upper system was designed from what Kevin did. The design in my drawing for the bottom assembly was my design.
 

DMcCauley

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You never posted your bottom design just the upper design that was based on Kevin's design so do not say it is your design. Give credit to where your idea came from. And yes my upper system was designed from what Kevin did. The design in my drawing for the bottom assembly was my design.
Whatever. Firstly, I think its pretty crass of you to accuse me of copying your design based solely on the viewing of a simple test video which shows absolutely no detail of the design in question. Secondly, what "exactly" is your design? The only thing you ever posted regarding your "design" was an extremely basic sketch that contained absolutely zero technical information. Thirdly, our design has gone through about five different iterations so far for the lower hinge pivot, so the engineering, machining, and testing that has gone into that design has been significant and quite costly. To make the accusation that i somehow stole this from you is not only insulting, its quite absurd.

And if you want to know where the "concept" of my bottom hinge came from it was from a statement made by Will Merchant in the previous referenced thread.

Hi Kevin:
Instead of using two of Dave's gizmos on each strap-on, what about using one forward and have the aft end of the booster retained with a latch that disengages when the booster rotates away from the top? Isn't that essentially what your design does? The other difference being the use of a frangible plastic bolt in Dave's, of course.
Best wishes,
Will
Plus, the lower pivot design i've been working has gone through about 5 different iterations and testing to where we got now. If you are going to accuse me of stealing your design and tell me all the engineering i've put into this particular lower hinge design is "your own", then thats insane. In fact, the lower pivot design has changed about 5 times already and is still evolving. We still need to correct some lateral motion in the pivot design and this will result in yet another machining iteration. And at that, the design still isn't finished. We had major failures on the last test and will be redesigning additional aspects of the design including the upper carrier.

So, i'm not sure what your problem is, but i would recommend acting a bit more mature and stop making blatantly false accusations against others. As they say in science, burden of proof is the sole responsibility of the individual making the claim. So unless you can provide some hard evidence that i "stole" your design, that i advise you keep your trap shut.

This is my last response to this issue.
 
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DMcCauley

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I'll post some more videos soon folks.
Plus, if anyone is interested in the full details of the design, i'll be happy to share them with you.
Just send me a PM.
 
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fox_racing_guy

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Thanks for the real drawing DMcCauley, I think I might try and make 1 myself.
 

DMcCauley

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Thanks for the real drawing DMcCauley, I think I might try and make 1 myself.
Here are some photos as well of the top assembly.

Also a note, that these carriers won't allow a 98mm motor to pass through them as that back end would pose an interference. We are using 75mm motors, although we can use smaller 98mm motors.

If you need any other info, i'll be happy to share it with you.

 
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DMcCauley

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Also, here is a schematic of our custom sequencer I designed. Fairly simple using just a PIC18F uProc with a bunch of timer routines. Launch detection via a G-Sensor or Breakwire. This will control both airstarts of the booster motors as well as separation.

Also uploaded is the conceptual flowchart, although this has already changed as well.

Note, the schematic is an early revision and doesn't have all the hardware RC (debounce) circuit values shown or LED current limiting resistor values shown. I also don't believe it shows the pull-down resistors on the igniter output gates. I'll have to upload a more recent version later.

View attachment sequencer_schematic01.pdf

View attachment sequencer_flowchart072809.pdf
 

powderburner

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Just so you both know, neither of you came up with this type of linkage first. This has been used for decades as the aft structural attachment/release for external fuel tanks on a certain aircraft. And before that it was used for the aft structural attachment/release for a very large centerline pod on a certain supersonic bomber. And before that I am sure the same concept was used in other places as well.

Good ideas get used a lot.

You two should "shake hands" and work together to make a better version for rocketry. Can you make it lighter? Cheaper? Simpler? If you laser-cut some of the pieces from lite ply, and maybe used spruce dowels or other good-quality materials, could it still be made to work for low-power? There is plenty of room for everyone to work on a piece of this technology.
 

DMcCauley

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Just so you both know, neither of you came up with this type of linkage first. This has been used for decades as the aft structural attachment/release for external fuel tanks on a certain aircraft. And before that it was used for the aft structural attachment/release for a very large centerline pod on a certain supersonic bomber. And before that I am sure the same concept was used in other places as well.

Good ideas get used a lot.

You two should "shake hands" and work together to make a better version for rocketry. Can you make it lighter? Cheaper? Simpler? If you laser-cut some of the pieces from lite ply, and maybe used spruce dowels or other good-quality materials, could it still be made to work for low-power? There is plenty of room for everyone to work on a piece of this technology.
My point exactly. Kind of like saying I copied Mr. X's fin design because I also used epoxy to attach my fins to the rocket. Plus, when i refer to "my design", i'm am talking about my particular implementation of the linkage into my rocket, not the *actual* linkage.
 

TheAviator

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I'm kinda curious. Those pieces are machined for a particular diameter rocket and are mounted.... where? My best guess would be an MMT centering ring, but that would make them relatively difficult to get to, wouldn't it?

Another question: I saw smoke coming from the inside of your main airframe after the test. This isn't going to cause a premature ejection of the main airframe laundry, is it?

Finally, how are deploying recovery devices in the boosters? Not that I think it is particularly difficult, just my curiosity.

Overall, a really cool *cough* implementation.
 

DMcCauley

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I'm kinda curious. Those pieces are machined for a particular diameter rocket and are mounted.... where? My best guess would be an MMT centering ring, but that would make them relatively difficult to get to, wouldn't it?

Another question: I saw smoke coming from the inside of your main airframe after the test. This isn't going to cause a premature ejection of the main airframe laundry, is it?

Finally, how are deploying recovery devices in the boosters? Not that I think it is particularly difficult, just my curiosity.

Overall, a really cool *cough* implementation.
Hey! Glad you asked! Anyways, the top centering ring of the motor tube has threaded inserts in which the carriers are mounted via 10-32 screws. Basically, you would prep the complete carrier with BP and insert the rod / oring / shear pin into the carrier. Then you would insert the carrier (with attached) rod through the hole as shown in the photo below and then using a long allen key, secure the carriers to the motor mount via the screws. Very simple. The boosters are than affixed to the rods via two screws which again are accessed from the top of the booster tube.

Yes, there was lots of smoke here. We used MUCH too MUCH BP for this test, which actually damaged the top motor centering ring. With less BP, there is very little smoke, plus the section will be attached with shear pins.

For recovery, we will be using mini/AWD altimeters with "poor man's" dual deployment on each booster. The boosters will eject at about 5000 feet, and because of their lack of fins (and thereof lack of stability), the boosters will tumble (as opposed to going ballistic). Then at 1000 feet, the main chutes will open up on the boosters. This also will work well in the event that if a booster doesn't separate from the main, the chute won't prematurely eject (i.e. chute deployment based on timer) and cause a major inflight break-up of the main.

Hope this makes sense.

Photos below show the dry fit of the upper assembly, and also a photo of my good teamate Randy installing the carrier assembly as described above.

carrier01.jpg


carrier02.jpg
 

DMcCauley

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Here are some more photos from my camera of Test No.2. Test No. 2 was supposed to only be 0.5grams FFFF, but i got lazy and didn't measure so it was closer to 0.75grams FFFF. (Looking at my results, even 0.25gram is MORE than enough!)

The electronics bay shown here is for the sequencer. There is presently a "blank" sequencer board which was just installed for fitment purposes and also (2) 9V battery holders.

booster01.jpg


booster02.jpg


booster03.jpg
 

DMcCauley

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And here are a few shots of the finished sequencer board. Hardware is finished, now just completing the firmware.

The third photo shows shows the acceleration switch.

seq01.jpg


seq02.jpg


seq03.jpg


seq04.jpg
 
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TheAviator

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There has GOT to be an easier way to do that! Just saying!

And that is a lot of fire for .75g of BP. How badly did you damage the mount?
 

DMcCauley

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There has GOT to be an easier way to do that! Just saying!

And that is a lot of fire for .75g of BP. How badly did you damage the mount?
I'm sure there is, but it wouldn't be as fun! :) I have more fun actually doing the designing of everything that actually flying the rocket.

The carriers basically lifted up from the threaded inserts they were installed into on the 3/4" upper bulkhead and split the wood somewhat. As a fix, we are going to use less BP of course, but also use aeropoxy structural epoxy to repair the 1-2 laminations which lifted (aircraft 13-ply birch), and then redrill the carriers with 1/4-20 clearance holes. Then use a real solid 1/4-20 threaded insert which will be screwed into the wood from the BOTTOMSIDE of the ring. The original inserts were some 10-32 inserts which i had which were really meant for plastics, not wood. The new inserts actually screw all the way through the wood and have a flange on them as well. I was going to use this type originally, but because of the flanges, i couldn't fit them close together with the original 10-32 holes.
 

NJnike

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Here are a couple shots of the damage from the last test.

IMG_0181.jpg


IMG_0176.jpg
 

TheAviator

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That is some serious damage! I guess this brings new importance to the saying "Measure twice!"
 

bassdoc

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This may be too simple of a questoin for the people following this thread, I am really interested. Where do you put the powder, and does it just kick those rods out or is there some other mechanism that I don't see?
 

n5wd

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Here is a video of our booster separation test no. 2...
As they say down here... that was definitely 'with authority'. Speaking of which, have the locals (PD/FD) dropped by for a neighbor-inspired visit, yet? :shock:
 

DMcCauley

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As they say down here... that was definitely 'with authority'. Speaking of which, have the locals (PD/FD) dropped by for a neighbor-inspired visit, yet? :shock:
Only when i put my fullscale Hellfire out on the lawn!

 
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