Mach 3?

In my level 3 thread, I mentioned a design I came up with on rocksim. It's a 98mm minimum diameter rocket built for the Aerotech N4800T. It sims at about 35,000 feet with a maximum velocity of Mach 3.2.

I was wondering, what would you have to do to make a rocket withstand mach 3? The tubes would be made from carbon/kevlar hybrid cloth, as well as the nosecone. It would be a conical nosecone. You would probably need an aluminum or steel tip to withstand the tremendous heat generated. My dad had an idea to increase the longitudinal(sp?) strength. He said epoxy in 4-6 wooden ribs inside the tubes.

What else would you have to do?

BTW. I'm not planning on doing this anytime soon, if at all, so there wont be any pics.

WE WANT PICS ANYWAYS No excuses. Do we have to send V & T over again? Man, they've been overworked this season...

For the cone, you'd be all right with just a carbon-kevlar or glass laminate covered in some sort of heat resistant paint. The paint will ablate off and you will be left with a nice lumpy nose cone I highly recommend using an aluminum tip, as you suggested. For more information, Bill Farr, a guy from our club, has flown rockets this high/fast. PM or e-mail me if you're interestd and I'll give you his e-mail.

All right, you want pics? Here's a self portrait. The weird lump on my arm is from hitting the pressure point on a knob on a school locker.

LOL! Of course, we meant photos of your forthcoming carbon-kevlar layups, because now that you have mentioned it, you must complete this project. Or else V & T will still have to come over

I have no experience with it but a min diameter rocket on even an O motor would only be in the Mach 2-3 range a few(+) seconds and supersonic just a handful of seconds more, would heat really be a serious issue?? Anyone have data on this??

Hmm, first of all Nick, for living on the East coast, you're crazy Second of all, I would say that an aluminum cone would be much better. Why screw around with all of that and have a cone failure when you can just use an entire aluminum cone. And yes, it would be allowed, because da rulz claim that any metal that is NESCESSARY is allowed, and if you ask me, mach 3.2 makes it nescessary!
I gotta see this thing. When somebody close by starts fooling around with Carbon Kevlar hybrid fabric, I get intrigued. And a project of this magnitude, of course I'd wanna contribute my know-how. My funds as well! lol, sounds like an interesting project, and if you build it light enough, and it sounds like it will be dang light, fly it at CTRA on a G

A minimum diameter project on an N or O motor, depending on the motor, will be supersonic for 4-8 seconds. A guy from our club did an M to M two-stager that was over mach for about 10 seconds. The carbon laminates over the fins were peeled back and charred, and all the paint was burned off the nose cone. I thought it was cool

You all make it sound like i've already started this. I have no intentions on doing this any time soon. Maybe when i'm in my 20's or 30's and I make enough money.

I would think that the fiberglass tubing from Giant Leap would do well in this case. An aluminum cone would be a very good choice. but I bet a solid wood (maple) one would do fine as well. I also wonder if aluminium tubing and fins might be a great idea. I don't know if metal tubing is verbotten on L3 attemps. It would not really be any more dangerous than flying peices of G10. Sounds like a cool project. I have a really good method of mounting the shock cord for min. diameter rockets if anybody cares.

Leica
(camera and space dog)

Hey Leica -- do tell! I just ripped a shock cord out of my 3" minimum diameter bird last weekend...

Maybe all-aluminum with a 'glass fin canister and nose cone? Hmmm... I'll have to get started on a design for an O motor...

Originally posted by Leica

. but I bet a solid wood (maple) one would do fine as well. I also wonder if aluminium tubing and fins might be a great idea. I don't know if metal tubing is verbotten on L3 attemps.
Leica
(camera and space dog)

Click to expand...

In the early 90's when Kosdon was doing 2.5" motors on the way to making the O 10000 he was using maple nose cones and they were OK with L's but would come apart with an M. The failures were interesting, all the wood would come back but the best description was they looked "frayed".
All Aluminum is OK for an L-3. Dr. Rocket used his Modular rocket for an attempt.
I may have posted this link before, https://www.ahpra.org/thunderb.htm this rocket went nearly M-4 and the paint stayed on the fins. The missing paint on the motor tube is from the heat of the smoke grain. Was over M-1 for a minute.

Mark

I came up with this when I was rebuilding my 54mm Acme fin can rocket.

1. Parts: 6" coupler that is a good fit for your main tube, 2 Bulk plates that fit inside the coupler, Forged closed end eye bolt with 2 nuts and 2 washers.

2. Tools: Epoxy (30min.), Coarse sandpaper, Knife, saw or dremel with cut-off wheel, masking tape, broom stick or other pusher rod, long dowel, plastic spoon, flash light, drill and bits, wrenches.


3. Cut coupler into two equal pieces, rough up the outside of one of the couplers with the sand paper. Wrap your broomstick with coarse sandpaper at the end make it so you can rough up the inside of the main tube. Rough up the inside of the tube about 6" in front of where your longest motor will end. Tape the plastic spoon (or a metal one you've stolen from the kitchen to the dowel. This is used for applying epoxy inside the tube. Apply a liberal bead of epoxy just aft of where you have roughed up the inside of the tube. The idea is to get the half of the coupler epoxyed inside of the tube to act as the stop for the shock cord mount. I bought a really long 54mm coupler to use for a pusher but you can make one using a broom stick and a little ingenuity. This is just like putting an engine block in an Estes kit just a bigger tube and farther up inside, it is also a bit like being a snake proctologist ;-). Try to give the coupler a twist as you put it in to spread the epoxy. I would also mark your pusher to be sure you are getting your coupler were you want it. Withdraw your pusher as soon as you get the coupler into place. Keep the tube level in case you have some epoxy that wants to run out. If you are having trouble with excess epoxy make a giant q-tip with a rag and your dowel, use this to swab the excess away (flash light will help here).

4. Take the other half coupler and rough up the inside of it with coarse sandpaper. Drill holes into the center of the two bulkplates to fit the eyebolt. Rough up all sides and edges of the washers and the bulkplates. Degrease the eyebolt threads and nuts with laquer
thinner. Rough up the surfaces of the nuts. Epoxy the bulkplates together and using liberal amounts of epoxy mount the eyebolt into the bulkplates so that you have the componets in this order: nut, washer, bulkplates, washer, nut. Use lots of epoxy to bond the whole assembly together. Afler the bulkplate assembly has dryed mount it into one end of the coupler with lots of epoxy. Leave it about 1/4 from the end so that you can put liberal fillets on both sides. When all has dryed drill four 3/8" holes in the bulk plates so that it will pass the ejection gasses. Be sure to make this assembly really strong as this is the mount. You may even want to turn this into a baffle using another bulkplate with holes in it.


5. Now you have 3" coupler bonded inside your body tube and a 3" coupler with an eyebolt mounted in it. Attatch your shock cord to the eye bolt (tubular nylon or kevlar) I sew mine using kevlar thread, but you can knot it, or combine the two. Now drop the shock cord into the aft end of the rocket and pull it through from the front. This should seat the shock cord mount behind the coupler you bonded into the tube. If the mount is loose in the the tube use some tape to shim it up a bit.

6. This mount leaves the tube clear in front of it, and you can remove it after a flight and inspect the shock cord for burn damage. It also lets you change out the cord. You may want to scale up the hardware and bulk plate attachment depending on the size of the rocket.


Somebody on RMR or RO named this the "Brown Bulkhead"

Leica,

(D.L. Brown)


I hope this comes out clear enough...

Oh boy, David, it looks as if we are going to have to build a test vehicle to demonstrate how to go Mach 3 and come back intact (well, for the most part anyways). I am thinking an O motor should be adequate.

On another note, I am working on a 4" minimum diameter rocket. I hope to have it ready for BALLS next year as revenge for my debacle this year. It is a long shot to geve it ready, but I'll give it my best effort. For all of you that remember the thread about my BBX that i was working on. I just realized that my reinforcements were overkill for any 3" motor, so the kevlar and glass reinforced tubes are going into this rocket. Don't ask for pics yet though, as there isn't much to take pics of. . .


Anyways, rocketman, now that you brought it up, the only way we are going to let you off the hook is for you to build the rocket and take many pics!!!

I know... let's drag race! See you at BALLS next year Nick :kill:

Originally posted by Rocketman248
The tubes would be made from carbon/kevlar hybrid cloth, as well as the nosecone.

Click to expand...

Use all carbon cloth. You'll be much better off.

We just recently completed a project (2 stage min dia K1100 to J135) with the types of tubing your talking about but special attention for your idea has to be giving to a number of areas. At the speeds and length of time at the speeds your talking about, aerodynamic airframe heating could become a big problem. From both internally (motor) and externally (skin friction)

We solved part of this by using a paper liner for our airframe. (Ok well Estes BT-70 tubing but a paper liner sounds better) On top of this we had a layer of 10.8oz all carbon bi-axially braided sleeve, then a layer of 5.8 oz carbon/kevlar bi-axially braided sleeve that we sourced from an industrial supplier. Best part was no seams, and the more you pull on the braid, the tighter it becomes around the tubing, so we achieved excellent results.
Carbon/kevlar is not an ideal fabric for most rocketry applications. Kevlar is not nearly as stiff as carbon, you would be much better of with 2 tows of carbon, rather than 1 of carbon and 1 of kevlar. We used the carbon/kevlar more for looks, impact and abrasion resistance and the ever-present "cool factor" I attached a picture of a sample of tubing we made as described above, minus the paper liner.


We were using a long burn motor (J135) so we were certainly concerned about heating from the motor, more so than external friction based heating. Hence the paper liner on the inside. Paper could be an excellent outer layer though, as its ablative in nature. (think motor liners) Maybe a wrap of paper or some other material imbedded in the outer epoxy would work. This is where some sample tubing, blowtorch and your foot would produce some really useful data.

We had known from practical experience that West Systems Epoxy and carbon cloth would hold up to much more stress and heating than we were attempting (M1939 min diameter made completely from 4 layers of 5.8 oz carbon) so we didn't do anything to help limit friction heating. The same project mentioned above used a commercial 4 in fiberglass nose cone, and had no ill effects from heat and/or stress so we also went with a commercial 54mm nose cone, reinforced with fiberglass to allow a walston to sit up there.

Another member in our local club is doing a N2000 to N2000 2 stage, and after a bit of calculations and stuff, decided to use a fiberglass nose cone with a added machined aluminum tip.

If you *have* to use the carbon/kevlar style cloths, use it for a outer layer so you can take advantage of kevlar's impact and abrasion resistance.

My next project is going to be similar in nature, but using an aluminum “frame” , no motor mount, just properly sized centering ring and struts in between, with a outer “aero-shell” of braided carbon airframe.

Nick Anderson

Originally posted by nichanderson
If you *have* to use the carbon/kevlar style cloths, use it for a outer layer so you can take advantage of kevlar's impact and abrasion resistance.

Click to expand...

And it's pretty Sorry for the incoherent comments tonight, guys... my brain is fried *g*

Funny thing, I was thinking about doing this very same project in a couple years too... the only difference was mine is 3" diameter and will be designed to eat a M3000. Then I saw this thread... It answered some questions I was asking myself about it.

Dougs idea may be better. N4800T=$2,000. M3000ST=$400. hmm...$2,000 or $400. Decisions, decisions. On the other hand. People fly M motors all the time. It's not often you see an N4800.

Nah... I'll just whip up an N5000 EX load We'll be flying in no time.

David, David, shame. we need an N8000 , then we can go Mach 5!

something like a 1.5" nozzle throat, and then go with 90% solids loading and 20% aluminized!

Originally posted by rocwizard
David, David, shame. we need an N8000 , then we can go Mach 5!

something like a 1.5" nozzle throat, and then go with 90% solids loading and 20% aluminized!

Click to expand...

Bah !

Give me a N200 and I'll beat you any day... ;-)


Nick
"Remember, lower equals faster ;-) "

Originally posted by rocwizard
David, David, shame. we need an N8000 , then we can go Mach 5!

something like a 1.5" nozzle throat, and then go with 90% solids loading and 20% aluminized!

Click to expand...

Use a steel motor casing and you could do it..

Nick

Now yer talkin'!

I just did some sims for a 3" rocket on an M3000. It went just over 20,000 feet at around mach 2.5! That looks like a very possible project. Next year, when i'm done with boot camp and all my training, i'll tackle that project. I'd probably have to come over to Black Rock or something like that.

I would use all carbon fiber cloth like Nick said. I would also use an aluminum nose tip or make the whole thing out of aluminum for that added "cool factor."

Im thinkin' main at apogee. That would work right? It would definitely have to be dual deploy. I would need a tracking system as well. I would use an RDAS system so I can see exactly what it did.

This should be very cool. Once again, don't expect any pics anytime soon. I'm going to Navy basic training in february. Then i've got a couple of months of training after that. Once i'm settled down and have some free time i'll get started. I've got some extra carbon fiber and some fiberglass left over from my L3, I might try making a tube to practice.

Nah, you may not even need dual deploy on a rocket like that. If you build them strong and light enough, you can put a small chute out at apogee, (or maybe even a streamer) and then just have it come down rather fast. Dual Deployment only opens more problems, like when the main comes out at apogee.. Even at Black Rock, that could probably drift off the lake bed.

Oh, and rocksim often times is not very accurate in the alittidues and speeds you are talking about.

Nick

main at apogee is no problem, just stick a rocket hunter in it and you'll be fine.

Excellent, see you at BALLS next year. I can make/beg/borrow/buy a couple of 3" diameter M2400s. Let's drag race

Dual Deploy is cool, but I have seen it fail in more than one way. I think with a really highperformance project it is more important to concentrate on the safety of those on the ground and just get a 'chute out and have the thing come down nice and slow. A Walston might be good too!

Leica
(Camera and Space Dog)

If you want to do it RIGHT then do it with GPS...

https://www.gpsflight.com/GPSF/Uses.htm

Sure beats the hell out of following beeps around in the middle of a desert..

We had a flight at our last launch that went 9 miles downrange and were able to succesfully recover it... Went behind a hill, and just drove to the last know postion of the rocket according to the GPS, reacquired signal, drove a little more and picked it up in the middle of miles and miles of dense sagebrush...

Nick