inexpensive, yet "exotic" idea?

I am looking for a mid price rocket, this may I plan on doing a large flight, and maybe 2 or 3 "mid price flights" (in the price range of $100-$150) and a K or two... I have a CF rocket and nike smoke for the K's, freedom won is the large project, butI want something interesting and new that I could work on for may... I have two CTI pro38 6 grain casings, might as well take care of those... I am really interested in a cluster rocket, but not your regular 3 fin and a nose cone cluster, I want something "exotic"... any ideas? I have a parachute good for a 14-16 pound rocket, recovery harness, some of the nose cones I have available are a 4" ognive, 7.5" ognive, several 2.6" cones and a 5.5" nike smoke cone... I would like to make use of as much stuff as I can. Any good ideas? I also have a ton of 1/4" wood laying around, so as you can tell I want to use a lot of my resources to keep this rockets price down, so that I can get several flights out of it next year... depending on what you guys come up with I might even decide to not fly freedom won in may (and save its second flight for october) so I can afford several flights with this bird. Freedom is a fun rocket but with the cost's and VERY slow precise prep, and stressful pad setup, it is worth skipping it for some nice easy flights, maybe I will leave out the J400's, and fly freedom on a K550... ok now bring on the ideas!!!

Also, I am getting a 54/1760 motor with regular and extended closue, K185W would be cool in the CF rocket, but I think it would be a really cool airstarted motor, so any ideas that incorporate an exotic design with two J400's lit on the ground, then a K185 or other 1760 load in the air... another cool flight would be a pair of J400's and a redline K695... I want something that can be used with dual deploy, and will go a little higher then freedom won would... so I think I have the basic idea down, just need some great ideas for what to make the actual rocket of... gosh, I just keep coming up with more things I have that would be perfect for this... I have some 54mm tubing... so I could use that as the motor tube for the 1760 load...

This is a 5.5" airframe.
Central 75mm M and outboard 38's that are airstarted.

Also have a version with outboard 54's that are lit via head-end.

Good fit & finish will keep you up late and off the keyboard ;-)

Awesome, I would never have thought of that design; cutting through the motor tubes and fit onto the rings. Keep sending more pics!
What is the estimated altitude and speed?
Mark

That is pretty awesome, could you post a picture of the business end? And yes, I do need something rocketry related to keep me off the keyboard ;-)... what about drop away boosters? I am working on a 2.6" CF rocket for supersonic flights on 1760 loads... if I could add drop away boosters to that, it would be incredible! And wouldnt effect the final weight (parachute already picked out...)... I would want the J400's to "fall" off right as their thrust curve finishs off, so they are low enough for me to find them again... they would probably be made of a 38mm tube, about two long with a conical nose cone... so I need ideas on how to mount them and have them fall off, (I have Ray's book, I will read that section again...) and how to rocksim the boosters. I am guessing there is no way to simulate them falling off in rocksim... thanks! attached is a basic rocksim file (exact weight isnt in this file, and the fin design is not final) of the 2.6" CF rocket.

...

The flight would probably be a K185 and the two J400's, all three would have to be lit on the ground, drag would have to seperate the boosters with the J's and motor ejection would eject small streamers.

jraice,

Where are you getting all this money from, my friend? It seems you're starting a new thread everyday with how you're going to fly J400's and K's and whatnot. If I've learned anything, it's that money gets spent way fast and even though a part time job may pay $100 a week, you will have obligations and friends that will divert your money to places other than your rockets.

Good luck!

Jason

Well I dont know how I do it but I do... the only real thing with a "K and J400's" was freedom won, now I am basically building something with parts I already own... that will fly on the same motors as freedom, but will be smaller (easier to prep) and a little more of a speed machine, originally the rocket for this thread was going to be something new, but I am already working on a CF rocket this winter (all I need is fin's, then I can start building, plan to start tomorrow) and I thought, well that is already going to be a K rocket, why not add the two drop away boosters to that... I dont spend a fortune on rocketry... probably about $1000-$1200 a year on parts, and kits and all that... then I fly a couple of smaller rockets at single day launches, and spend about $400-$500 twice a year at the 3 day events...

Here is an "exploded" picture of some parts for "are we there yet"... it is 2.6" diameter and a little over 5' tall, it is the rocket I am considering adding the two drop away 38mm's to... EDT: Cant seem to get the picture to work, I will try copy and pasting it...

Picture attaching help? I have a couple I want to attach, cant figure out how to get their size down enough.

Well, I have decided on the drop away booster idea, and figured out how to do it in rocksim, just need a way to have the main motor and 2 boosters light on the ground, and just have the boosters "fall off" as they run out of thrust. Apogee has a pretty long artical about how to simulate it and the only "bad" or risky part is that the nosecones on the boosters cant be simulated (the weight can, but drag and CP cant), but I it is a rather small rocket so a K185 and two J's should lift it easily (nomatter how much drag it has) and apogee said the nosecones make the rocket more stable, with a long burn motor that can be a problem, but after burnout when the boosters fall off the CP will go back to a more "comfortable" amount...

Originally posted by freda

Click to expand...

Nice! Do you have a build thread online, or more photo's? I'd love to see how that was all put together.

Here is a very big and complicated project with drop off boosters:

https://www.insaneprojects.com/

I hade seen that site before, but I am looking for something that wont require electronics... something like Ray's method but without having to have the nose ejection. I could think of one thing... just use a channel of somesort and rail buttons so the boosters can fall off, but not go up... but then if the central AT K lights first (VERY unlikely but possible) then it will go without the boosters (unstable without the central tube) and then when the J's light it could get messy... I am not worried about the K185W though, it doesnt have enough thrust to be more then the J400 and have them fall off, even under thrust, so if I go with a standard burn motor, or a motor like a K1100T, the boosters probably wont go along for the ride , I will probably do a test flight with two J400's and an aerotech 38mm load... in march...

Come one guys, get your thinking caps on ;-), booster seperation is the only serious thing I need to figure out before I can start building...

There are many people that "target" my excessive posting, and I wont avoid the fact... I am, as many people are, obsessed with rocketry and enjoy posting on TFR, but sometimes I get so into it I post something that I could find the answer to somewhere else, or in this case I ask a lot of questions... you are one of the people that seems to "catch me" EVERY time I do this... I guess people shouldnt buy Mark Canepa's, or Ray Dunikans books, because they should come up with it on there own...? Is that what you are trying to say? I am sure when you were a toddler you heard this... if you dont have something nice to say dont say it, sorry to bring up such a childish "rule" but how to make a booster seperate at the burnout without eletronics is not something every person is going to know how to do... so why not give me a constructive post? I am not asking for the answer to how this entire booster system should work, while that would be nice , all jokes aside though, I just need a starting point to make a reliable booster release system... jraice

Jordan,

I know it must be frustrating to get that sort of response. But please keep in mind that we get frustrated seeing 4-5 posts in a row, perhaps 20-30 posts a day, of you merely "talking out loud". We could just NOT read anything you post, but we too are rocket addicts and we read everything. And everyonce in a while you have a geniune question, or something insightful to add, and we would rather not miss it.

If I can offer you a small piece of advice, on behalf of this entire board (because the number of people becoming familiar with your name, and not in the way you'd like them too, is growing steadily), please only post when you actually have something to say to the rest of us. Ask your questions, give us your advice, and please post your build pics as often as you want. But avoid the senseless rambling and repeated posts asking yourself questions, answering your own questions, or just babbeling in general.

As for your current question:
I don't understand your fear of electronics. But you are constantly asking how to avoid them when trying to accomplish something. Bite the bullet and buy some electronics. They're highly reliable, and very simple. Especially for someone with as good a grasp on rocketry as you have.

AND THE ANSWER (if you didn't know it already)
The correct way to deploy those drop-off boosters is with electronics. Just do it.

I will take that advice constructivily... as to the electronics, I am not afraid of them, I love my MAWD and mini timer... the MAWD will be in this rocket actually... thing is I dont want to have to use two timers, one in each booster, and I dont really know exactly how to get wires from the timer down to the boosters... some ideas/pic's of how you would wire it would be great... I guess I wire could just come out of either side of the alt bay, and then go down along side the boosters... I will consider it. So with a timer, what sort of "release" device would you recommend? Only one I have seen is using nylon screws and BP (blow the screw apart for seperation)... but that is pretty complex and was on a much larger rocket.

You run the wires through a conduit from altimeter or timer to the aft end. You need to search, search, search the net for information on how-tos. You see the conduit running vertically with the motor tube/ through the rings, it tells you how.
People would tell me, when I was a newbie, search, search and you find what you are looking for, the hard way, unless you want to buy a complete rocket. ;-)
Mark

I am very knowogable with the conduit design, freedom had a conduit for the airstarted pair of J's and had two extra threaded rods, you try getting a conduit that fits in a ring with a thickness of 1/8"... no exageration, all wiring would have to be external. After talking with Fred Azinger I think I will airstart the central motor (K185W on first full impulse flight), one because it looks cool and secondly, because it would allow the use of high thrust motors like the K1100T, the booster are not designed to take a high G liftoff like that, so if they fall away as the motor lights it wont be a serious problem, without the boosters a K1100T will get this thing to mach 1.35, cant wait to sim it with added speed of the J400's! Maybe with the boosters I will actually be able to get above 10,000'! My goal for 2006! Could even get above 2 miles... So I will have the timer go off just as the booster motors thrust is low enough that it isnt doing much, the timer will simultaneously jettison the boosters and light the main motor. Any home brewed strap on booster ejecters on the cheap? I hope to get some build pic's of the main section in the next couple of days, and then after the holidays I should have the parts to begin doing the boosters. I cant seem to figure out how to make the picture small enough to be attached to this forum though...

Sorry, but I didn't take many more photos or document the build in any way. I'm glad I took the pictures I did - I rarely do.

Here are a couple....



A couple of notes about the design....

- The outboards are sized to fit 38-720's exactly. That is the 720 motor in the original picture. If you look closely, the top centering ring cuts into the top of the 38's to form an upper thrust plate. This makes sure the motors are tied in tight. The lower two CR's have half-circle cut outs in them for the 38's to pass. Note: CR's by Pat at www.centeringrings.com

- The airframe uses a single flight computer (AFC-877) for all functions that is housed in a conventional Ebay in a conventional dual-deploy arrangement - the orange striped mid-section. In addition, there is an "airstart amplifier" in the top of the motor section. That is why there are the two all-threads at the top. This forms a small E-Bay at the top of the anti-zipper style motor section where the "amplifier" lives. The "amplifer" is a small circuit that has it's own battery....you can actually think of it as a solid-state relay....that fires major power into the airstart igniters upon command from the flight computer. I do this so that the flight computer is not really supplying the firing current.

- The flight computer must connect to the "airstart amplifier." To do this, I use thin wire-wrap wire to span the drogue bay. These wires carry the firing signal, but can be thin because they are not carrying any current. They are thin so they are easily broken when the drogue deploys.

- The "airstart amplifier" connects to a set of terminal blocks on the aft surface though the conduit you can see in the photo. On my version with the 54mm outboards, there are additional conduits to the top of the 54mm's for (optionally) using head-end-ignition for EX outboard motors.

Here is a lunch photo: Going up on a J415 with twin I285R's airstarted.





Photos by Rick Clapp

Thanks for that excellent description! I'm really interested in the airstart amplifier, sounds like a handy piece of technology. Did you build it yourself?

Yes, I designed and built it myself.
This is the second generation - now on my 4th.

What keeps evolving is the charge pump to make the firing voltage....early units simply just used another 9V battery....new ones use smaller, lighter cells and pump the voltage.

Otherwise, it is a simple circuit that charges the caps shown then fires them using a pair (one per igniter) of SCR's when triggered.
Very much like a solid state relay.

It is shown here all packed around the on/off switch, ready to be mounted on the inside of the rocket.

Nice! What was that main motor? Didnt look like any J415 white lighting I have ever seen ;-)... really though, that is pretty cool...

That's because it wasn't a J415 - it was a Blue Thunder, possibly J800.

Was a J-460T, not a J-415W.
I knew that sounded wrong when I typed it.
Busted!

Originally posted by freda
Was a J-460T, not a J-415W.
I knew that sounded wrong when I typed it.
Busted!

Click to expand...

Bingo - there's your answer.
(don't worry, we all make mistakes)

I remember one guy at the local club who (twice in a row) put up motors he was convinced were "H180W's." Both times, the rocket LEAPED off the pad, followed by a BRIGHT red flame, followed by a slightly embarrased: "whoops, guess that was an H210R."
Surprising though, adds an interesting twist. I've also once called a G33 a G64 - surprised me too when it lifted off.

Great pic btw. What was the alt on that flight?

That flight was a long time ago. It was the maiden/only flight.

I found the launch picture in the May, 2004 folder.

I didn't look close at the flame when I posted the photo, it was a dead give away.

The flight crashed.
This was my dumbest rocketry moment - a huge build project that took months was nuked in seconds - the real reason for the 54mm version - I didn't mention it was a rebuild of the 38mm version shown.

I preped this rocket in an environment of extreme distraction and paid the penalty. Despite the HUGE "UP" arrow printed on my altimeter sled, I managed to install it upside-down in the EBay.

The flight went something like this.....

3...2...1...0...oooohhhh.....airstart...Airstart...AIRSTART!....PARACHUTE.PARACHUTE.PARACHUTE.....S**T.

The rocket stalled at a short apogee of about 2500ft after burnout of the J-460T.
Obviously I never got any airstarts or deployment.
It then tail-slid back to crash about 50 feet in front of me.
Everything behind the Ebay, except the motors, was destroyed.

I built a new version with the 54mm and HEI capabilty.
Contruction is complete, just waiting for paint sometime this winter.
Loaded with a red EX M2400 and twin K900 Sparky's it sims to ~25k and mach 1.6!
Could be a good test for phenolic and plywood!

Oh no!

Yea, I finally had my first "low distraction" prep area last month. It makes all the difference. Unfortunatly it's hard to do sometime. When we go to launches, I bring my wife and kids with me. Also we get a lot of non-flying friends who come with us to watch our projects and to just enjoy a weekend out of the house. And they bring their kids too, heh.

But I think we've worked out most of the bugs now. Great, tragic story, btw.