Gt-R - A 29mm MD Rocket - Build Thread - MIA

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RAHagen

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Okay it time for my next HPR build. This rocket dubbed Gt-R will be my first step into the world of composite rocketry as well as supersonic flight.

Here's the rundown:

Airframe: 29mm thin-wall motor tube with 1-2 wrap fiberglass veil (6 Oz.)

Fins: Custom cut from PML or homemade fiberglass plates.

Electronics: Telemetrum for tracking and DD.

Recovery: Cable Cutter and 12" Parachute deploying at apogee and fully opening at 500 ft.

Max Altitude: 7233 ft on an I205

Max Velocity: Mach 1.8 on an H275

SSGP1.jpg

SSGP2.jpg

I've been designing this rocket for the past couple of months now and I'm happy that i'll finally be able to begin building it. I hope that I can use this rocket to be a learning experience so I can become better versed in the area of composites and (hopefully) be a stepping stone to builds such as a 38mm MD and larger, composite rockets.

As always, I welcome any and all suggestions, remarks, corrections etc...

View attachment Supersonic G v1.rkt
 
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So this is why you were asking about my tower huh? I'm not sure it will go down to 29 mm though. Have to see when it is finished.

The fun part is going to be how you get the electronics and charges in this thing.
 
So this is why you were asking about my tower huh? I'm not sure it will go down to 29 mm though. Have to see when it is finished.

The fun part is going to be how you get the electronics and charges in this thing.

Haha actually I've also been designing a 38mm MD as well, but hey! If it'll work it then awesome!

Yeah it's gonna be a tight fit but I hope I'll be able to do it.
 
Oh... Thanks for pointing that out. So I guess the next motor that is actually available is the I200 which will take it to around 7600 feet.
 
Awesome project!

Keep us updated

Thanks! I'm gonna try to keep this project going at a smooth pace.

I just ordered all the things I'll need for the fiberglass veil except the peel-ply, and brushes. It won't ship till January 5th so I'll have wait to start the build till then.
 
Thanks! I'm gonna try to keep this project going at a smooth pace.

I just ordered all the things I'll need for the fiberglass veil except the peel-ply, and brushes. It won't ship till January 5th so I'll have wait to start the build till then.

Don't worry about starting the build thread. By the time your stuff ships on the 5th, this thread will already be 3 pages long if current trends continue. Now for the million dollar question, what are you doing for a nosecone? 29mm cones seem to be as rare as hens teeth.
 
Don't worry about starting the build thread. By the time your stuff ships on the 5th, this thread will already be 3 pages long if current trends continue. Now for the million dollar question, what are you doing for a nosecone? 29mm cones seem to be as rare as hens teeth.

Yeah I've been asking myself the same question. When I first designed the rocket I designed it around the 29mm cone from shockwave but apparently they are still out of business. The only other one I've seen is a conical nose cone on apogee components which I'm saving as a last resort since I'd much rather have a von karman.

I've heard of people making their own nose cones so I might try that, but from what I've seen, and considering my experience with composites, whatever my end product would be it probably wouldn't be worth the money I put into it.
 
Yeah I've been asking myself the same question. When I first designed the rocket I designed it around the 29mm cone from shockwave but apparently they are still out of business. The only other one I've seen is a conical nose cone on apogee components which I'm saving as a last resort since I'd much rather have a von karman.

I've heard of people making their own nose cones so I might try that, but from what I've seen, and considering my experience with composites, whatever my end product would be it probably wouldn't be worth the money I put into it.


It's also 29mm which would be hard to make a nosecone for.
 
If you are not opposed to balsa, Semrock has some sweet noses. The are Ogive, not VC but they look right. If nothing else you could use them to make a mold.
 
If you are not opposed to balsa, Semrock has some sweet noses. The are Ogive, not VC but they look right. If nothing else you could use them to make a mold.

Thanks, I'm not opposed to balsa at all, but I'm not sure how it will hold up at supersonic speeds. The rocket's calculated to go as fast as mach 1.8 and I'd be worried it would fail. I'll look into them though.
 
Thanks, I'm not opposed to balsa at all, but I'm not sure how it will hold up at supersonic speeds. The rocket's calculated to go as fast as mach 1.8 and I'd be worried it would fail. I'll look into them though.
You could always coat with epoxy...
 
So earlier today, SinfulDarkLord PM'd me and offered to try and make a custom nose cone for this build. No set date on when it will be finished but so far it sound like the nose cone problem has been sorted out. :)

Side to that I've been tweaking the design a bit to make it more feasible and so far I have noticed that with larger motors I might not have the space to fit a parachute inside the body tube as well as a telemetry system. I started thinking I might try to drop it with no chute at all mainly because If I do that then I will be able to use larger motors. either that, or drop the rocket on just a streamer and put it in the nosecone.

Cl(VII), This surely will be interesting to see how I get all the electronics in this! :p :)
 
Tweaked the design a bit.

Now instead of a streamer deployed at apogee and a parachute at 500 ft, the rocket will tumble recover to 500 ft. where either a streamer or small parachute will deploy from the nosecone. I also added a full-length coupler for the av-bay and changed the tube to a thick-walled tube which I will order from apogee tomorrow along with a couple other miscellaneous parts.

View attachment Supersonic G v1.1.rkt

Now looking at a max velocity of mach 1.7 and max altitude of 7600 ft.
 
Thanks, I'm not opposed to balsa at all, but I'm not sure how it will hold up at supersonic speeds. The rocket's calculated to go as fast as mach 1.8 and I'd be worried it would fail. I'll look into them though.

Blunt balsa noses work up to at least Mach 1.3, I can confirm. They don't like getting bashed against dry lakebeds by the parachute repeatedly picking them up and dropping them. Nor do they like ballistic descent.

I think it would be perfectly fine for M1.8.
 
Blunt balsa noses work up to at least Mach 1.3, I can confirm. They don't like getting bashed against dry lakebeds by the parachute repeatedly picking them up and dropping them. Nor do they like ballistic descent.

I think it would be perfectly fine for M1.8.

It might be, but I think I'm going to see how the nose cone SinfulDarkLord is making me turns out.

I'll keep that in mind just in case though. ;)
 
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Order from apogee came in today with the airframe, and coupler/ av-bay.

I still have some worries about my recovery method. Would this rocket be considered small and light enough to perform either a tumble recovery or streamer recovery? At the moment I have it set up to fall from apogee on a streamer and then have a parachute at 500ft however I'm not sure there will be room. Having it single deploy with a streamer at apogee would greatly decrease complexity and ensure that I don't run out of room, however I'm also worried that it might hurt the rocket...

Any thoughts or suggestions are welcomed. :)
 
A streamer all the way down will work fine. Because this rocket is fiberglassed cardboard it will be really light and it is also very small. I think that affixing a chute with cable cutter would be hard to fit but also take for a long ride..
 
If your going to use the cable cutter the purpose of that mechanism is to make the folded up chute act as a streamer. Up until it reaches the altitude that you set it for, that is when the chute deploys and you have less of a walk.
 
If your going to use the cable cutter the purpose of that mechanism is to make the folded up chute act as a streamer. Up until it reaches the altitude that you set it for, that is when the chute deploys and you have less of a walk.


Exactly. To be honest I don't even know if you could fit a cable cutter with a chute in a 29mm rocket.
 
Agreed. I forgot to mention that I was not going to use the cable cutter anymore. Thanks for the answers, I was pretty sure it'd be fine I just wanted to make sure.
 
You could probably get away with a 12" chute. You want it to land close so a 12" chute should let it fall faster and at the same time not fall too hard. It just might even be perfect for such a small rocket as a 29mm.
 
Got some work done on the av-bay today. Bulkheads cut, and mounting hardware assembled. I also got all the glassine peeled off the airframe tube.

Also got a smaller battery for my telemetrum from apogee, and an email notification from US composites saying my glass and laminating epoxy is shipped. The package should be getting here around the 8th.
 
Agreed. I forgot to mention that I was not going to use the cable cutter anymore. Thanks for the answers, I was pretty sure it'd be fine I just wanted to make sure.

I don't know if you have a cable cutter already, but if not catch me at the next launch and you can have a look at one of mine. I think you could get a 29mm burrito easily with a cable cutter setup if you choose. The cutter is parallel with the burrito, so at least that dimension is in your favor.

All that being said the two compartment system is tried an true, just requires a bit more length. Just, please don't drop it on a streamer only...my car (or me) may be under it when it comes down.
 
Just, please don't drop it on a streamer only...my car (or me) may be under it when it comes down.

Don't forget about the thin mill chutes from Top Flight. They pack up incredibly small, so you can gain some space here. You could also do a thin mill streamer, which will get you a much larger streamer for the same space. This may help alleviate Chris's worry about the rocket landing on his car. Now if he doesn't see a 6x60" bright orange streamer and step out of the way, that's on him (literally). :D

Based on the sims, we really need to get into Corsicana so you can stretch the legs on this thing.
 
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Don't forget about the thin mill chutes from Top Flight. They pack up incredibly small, so you can gain some space here. You could also do a thin mill streamer, which will get you a much larger streamer for the same space. This may help alleviate Chris's worry about the rocket landing on his car. Now if he doesn't see a 6x60" bright orange streamer and step out of the way, that's on him (literally). :D

Based on the sims, we really need to get into Corsicana so you can stretch the legs on this thing.

That would indeed be my fault. Hadn't thought about a thin mill streamer.
 
Don't forget about the thin mill chutes from Top Flight. They pack up incredibly small, so you can gain some space here. You could also do a thin mill streamer, which will get you a much larger streamer for the same space. This may help alleviate Chris's worry about the rocket landing on his car. Now if he doesn't see a 6x60" bright orange streamer and step out of the way, that's on him (literally). :D

Based on the sims, we really need to get into Corsicana so you can stretch the legs on this thing.


I'll have to look into those, they sound pretty nice. As for the design, I think I've come up with a design that would work similarly to the way the GLR Mariah rockets work except minus so of the parts. It would allow the rocket to work both as a single deploy and dual deploy. I'll have to iron out the details later but pretty much what it entails is two separation points: one at the nose cone and one in the middle of the airframe. If I wanted to do a single deploy the parachute would deploy from the nose cone and if I wanted to do dual deploy it would separate in the middle. I still have some things to figure out about it but that's what I will most likely Do.

I can't wait to get out to the Corsicana site, my family is moving closer into Dallas soon so we will be around an hour to both sites.

Chris, I thought I'd use your car as a target, you know so I got something to aim for. You wouldn't mind right? ;) :)
 
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