Looking to build a 29mm minimum diameter rocket - I have a few questions..

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rockets

rockets

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For a couple of years I have wanted to build & fly FAST rockets!! Last year I flew a 24mm diameter 20 inch tall rocket on a Ellis G37-10. It was cool, but I want to fly something a little bigger. I have a LOC 29mm motor mount tube. the tube is 8" long and I might buy this nose cone. https://www.rocketarium.com/Build/Nose-Cones/1.1
The problem is, the motor I want to fly, an AT H135, is 8 1/2" long, so could I have the motor sticking out the bottom at around 1/2 inch? According to Thrust Curve simulations, this rocket would go maybe around 10K. and around 1,000 MPH. So I will need a tracker, with little space and a low budget would you guys recommend this? https://www.apogeerockets.com/Electronics-Payloads/Rocket-Locators/MicroBeacon and for a altimeter I will either use the PerfectFlite APRA or Jolly Logic altimeter one. Since the nose cone is 6" long, would that be enough to put a recovery system, shock cord, altimeter, & tracker??

Well, if everything goes well, I'm hoping to build it this summer or maybe sooner.
My budget, $150

Thanks,
 
No reason you can't as long as it is stable. Older single use used masking tape as the thrust ring.
 
cavecentral said:
No reason you can't as long as it is stable. Older single use used masking tape as the thrust ring.
Click to expand...

OK, unfortunately I don't have a real rocket simulator.
If anybody here does, and if you will use it for me using this info below, I will appreciate it!
8 inch long cardboard tube
6 inch long conical urethane nose cone
plywood 1/8 inch thick 3 fins
weight: 5 OZ
It should look something like this:
RECORD_BREAKER.png
 
timbucktoo said:
here is the link:

https://openrocket.sourceforge.net/download.html
Click to expand...

Thanks for the link,
But around a year ago (or so) I downloaded it. But then a lot of weird things started to happen to our computer. I'm not blaming OpenRocket but, just in case I didn't want to download it again and have more problems. Did a security check and there was something wrong. Once I downloaded it, before the problems started, I tried out OR. It worked really well, I designed a couple of cool rockets. But then I had to delete it.
Thanks,
 
I've built a couple of 29mm minimum diameter rockets and that doesn't look stable to me. I'll run your design through OpenRocket this evening but I'm guessing that you are going to need a longer tube. Also, 1/8" plywood fins may not survive 1000 mph.
 
Nathan said:
I've built a couple of 29mm minimum diameter rockets and that doesn't look stable to me. I'll run your design through OpenRocket this evening but I'm guessing that you are going to need a longer tube. Also, 1/8" plywood fins may not survive 1000 mph.
Click to expand...

OK Thanks, I really appreciate it!!
Thanks.
 
Here is the video of my 24mm diameter rocket on a Ellis G37-10 from last year. Thanks to Bob Jablonski @ County Line Hobbies for the motor and the Starlight "Flash 24" I slighty modified the rocket.
Skip to 3:48 for the launch
[video=youtube;dbjV2kEfYyw]https://www.youtube.com/watch?v=dbjV2kEfYyw[/video]
Thanks,
 
I put your rocket design in OpenRocket (I made the assumption that your design has 3 fins). As I suspected, the rocket is unstable with a H135 motor. The first problem is that you have not allowed any room for the nose cone shoulder. If we assume that the nose cone will have a 1" shoulder, then the H135 motor will overhang the end of the 8" body tube by 1.5". This moves the CG aft which reduces stability. The other problem is that your fins are too small. With your design, the stability is about negative 0.5 cal with a H135 motor. For the rocket to be stable it should have a positive stability of at least +1 cal.

32737411204_0936f9eae3.jpg


Assuming that it is possible to fit all of the electronics and recovery gear in that little nose cone, the rocket can be made stable (even with the big H135 motor hanging out the bottom end) by making the fins bigger and changing the fin shape and adding some nose weight. If the fins are shaped like this, and 1 oz of nose weight is added, then the stability is about +1.1 cal. Flight simulation with this configuration is max altitude 6433 ft and max velocity mach 1.6 (1248 mph).

33451304031_0c85c5bc74.jpg


It is unlikely that any RSO would let you fly a rocket that looks like that. A better option would be to use a longer body tube. This would improve stability, make room for the recovery gear, and and would also allow the motor to actually fit in the tube.
 
That particular nosecone is solid urethane, so it would be pretty difficult to get anything in there. If you need to order a nosecone anyway, adding some 29mm tubing and a coupler wouldn't raise your cost all that much.
 
DGBrown said:
That particular nosecone is solid urethane, so it would be pretty difficult to get anything in there. If you need to order a nosecone anyway, adding some 29mm tubing and a coupler wouldn't raise your cost all that much.
Click to expand...

Just buy a new length of 29mm motor tube. adding a coupler (on the inside) would act as a motor block, and you'll still have the motor hanging out the end.
 
I would suggest getting a 3d printed custom Nose cone from someone on the forum. The one that you have there doesnt look like it will get much altitude or speed. A 6:1 VK shape would do well.

Plywood is an decent material for the fins but if you want them to hold up for a lot of flights, i would suggest using fiberglass or carbon fiber. You can also make FB and CF fins thinner, which will get you more altitude. Also, most H motors in a 29mm MD will probably break mach and as a result can go unstable which is why i suggest increasing the fin area a bit to get over 2 cal.

The body tube looks like it could use a little length for space to store the electronics and also get more stability. Maybe use a coupler to connect two body tubes together..?
 
TRFfan said:
I would suggest getting a 3d printed custom Nose cone from someone on the forum. The one that you have there doesnt look like it will get much altitude or speed. A 6:1 VK shape would do well.

Plywood is an decent material for the fins but if you want them to hold up for a lot of flights, i would suggest using fiberglass or carbon fiber. You can also make FB and CF fins thinner, which will get you more altitude. Also, most H motors in a 29mm MD will probably break mach and as a result can go unstable which is why i suggest increasing the fin area a bit to get over 2 cal.

The body tube looks like it could use a little length for space to store the electronics and also get more stability. Maybe use a coupler to connect two body tubes together..?
Click to expand...

Ahhhh, Remember this is a young man venturing into this realm. I recommend keeping it simple for the first time. An Apogee Aspire clone would be simple, cheap and break Mach for him on a G80-10. With an SU motor, lose it and no big deal. This fellow may be of limited means and his youth means there is plenty of time ahead to plan big. And Oh, how my plans
have changed by observing others and myself coming to the self-realization that some of what we do may look easy but getting it pulled off successfully can be quite hard.

Losing a hard earned project right off can be very disheartening and going fast on a minimal investment can soften the blow. Kurt
 
ksaves2 said:
Ahhhh, Remember this is a young man venturing into this realm. I recommend keeping it simple for the first time. An Apogee Aspire clone would be simple, cheap and break Mach for him on a G80-10. With an SU motor, lose it and no big deal. This fellow may be of limited means and his youth means there is plenty of time ahead to plan big. And Oh, how my plans
have changed by observing others and myself coming to the self-realization that some of what we do may look easy but getting it pulled off successfully can be quite hard.

Losing a hard earned project right off can be very disheartening and going fast on a minimal investment can soften the blow. Kurt
Click to expand...
I was under the impression that he was an L1 and wanted to build a rocket from scratch. Sorry, my bad.
 
Andrew, welcome!

From your signature, you are 13. Awesome! However, you will need to get someone L1 certified to be the official flyer for H and above. Sounds like you have a club that you fly with, so that shouldnt be a problem.

I think you might want to consider a kit for this endeavor. The rocketry warehouse GoDevil 29 is $50. Minimum diameter 29mm, fiberglass. Should be able to take any motor you can fit in it. Willing to bet some club members would mentor you through the build process. I've got the 38mm version, going to try for 20k' and M2 this summer.:wink:

That would leave you $100 of your budget for other things. You might see if someone is willing to lend you a tracker, which would also cut down on cost.

The advantage of a kit is that you know that all the parts should work well for your intended purpose.

If you are designing your own, I would second the suggestion of a longer body. Mr. Bob may very well have what you need in stock.

Whatever you decide, please share a build thread!
 
75Grandville said:
Andrew, welcome!

From your signature, you are 13. Awesome! However, you will need to get someone L1 certified to be the official flyer for H and above. Sounds like you have a club that you fly with, so that shouldnt be a problem.

I think you might want to consider a kit for this endeavor. The rocketry warehouse GoDevil 29 is $50. Minimum diameter 29mm, fiberglass. Should be able to take any motor you can fit in it. Willing to bet some club members would mentor you through the build process. I've got the 38mm version, going to try for 20k' and M2 this summer.:wink:

That would leave you $100 of your budget for other things. You might see if someone is willing to lend you a tracker, which would also cut down on cost.

The advantage of a kit is that you know that all the parts should work well for your intended purpose.

If you are designing your own, I would second the suggestion of a longer body. Mr. Bob may very well have what you need in stock.

Whatever you decide, please share a build thread!
Click to expand...

Is there a file for that rocket for RockSim??????
I just got RockSim Trial!!!!!!
 
75Grandville said:
View attachment 315298

Here's a first order approximation. Scaled from the 38mm version.

If you contact MadCow they may have something closer.

https://www.madcowrocketry.com/go-devil-29/

Easy Research Rocketry also has an inexpensive 29mm MD shock cord anchor: https://www.etsy.com/listing/480117942/29mm-shock-cord-anchor?ref=shop_home_active_2 Haven't used it yet, but just ordered one.
Click to expand...

Thanks for the info. I like that rocket, but I would like to fly a rocket that is more like 5 or 6 OZ.
I don't have an L1, but I have a older brother with a L2 who can assist me, and I'm hoping to try out the Tripoli Mentoring Program. I'm looking at doing a scratch-build.
14 inch long body tube
6 inch long nose cone
weight 5-6 OZ
(3) 1/8 or 1/4 inch plywood fins
kevlar shock cord
big, light streamer or a small parachute
OVERALL LENGTH 20 Inches
_____
So what do you think of my modifications to my design??
 
ksaves2 said:
Ahhhh, Remember this is a young man venturing into this realm. I recommend keeping it simple for the first time. An Apogee Aspire clone would be simple, cheap and break Mach for him on a G80-10. With an SU motor, lose it and no big deal. This fellow may be of limited means and his youth means there is plenty of time ahead to plan big. And Oh, how my plans
have changed by observing others and myself coming to the self-realization that some of what we do may look easy but getting it pulled off successfully can be quite hard.

Losing a hard earned project right off can be very disheartening and going fast on a minimal investment can soften the blow. Kurt
Click to expand...

I built a 24mm minimum diameter rocket last year. Video is (up a few posts) I lost the nose cone with a $40 altimeter. Tough loss, but I am ready to build another again!!! :grin: :clap:
Skip to 3:48 for the launch of that rocket.
_________
Thanks for the info, I'll look into the Apogee Aspire.
Thanks,
 
rockets said:
I built a 24mm minimum diameter rocket last year. Video is (up a few posts) I lost the nose cone with a $40 altimeter. Tough loss, but I am ready to build another again!!! :grin: :clap:
Skip to 3:48 for the launch of that rocket.
_________
Thanks for the info, I'll look into the Apogee Aspire.
Thanks,
Click to expand...
Do you want to build this from scratch or from a kit?
 
rockets said:
I built a 24mm minimum diameter rocket last year. Video is (up a few posts) I lost the nose cone with a $40 altimeter. Tough loss, but I am ready to build another again!!! :grin: :clap:
Skip to 3:48 for the launch of that rocket.
_________
Thanks for the info, I'll look into the Apogee Aspire.
Thanks,
Click to expand...

You're welcome! Certainly nothing wrong with planning ahead but enjoy the ride. After my L1 I jumped into a 4 inch diameter rocket I wanted to stuff an L motor in.
Unfortunately, it was out of cardboard LOC tubes I just "glassed" with a nylon stocking and bar top coating. Showed the tubes to folks "in the know" and they directed me to put "real" glass cloth and laminating epoxy over it. After that, I learned about fiberglassing fincans and read about a layered approach of going up
1/3, 2/3rds and full span layering of glass cloth on the fins to avoid fin flutter. Had to cut 12 pieces of fiberglass and talk about tedious! That was 10 years ago, the rocket is in paint, I need to wire up the two altimeters and the airframe will likely take an L1400 with no sweat. I spent the rest of the time flying smaller projects and acquiring skills along the way. This rocket will fly and since it has evolved over time, it stands a much better chance of a successful flight.

Aim high, plan much, be methodical and do not be discouraged if things don't turn out like you thought they would.

Also, did you get registered for the youth forum? You could also get advice there and compare it to what the oldsters tell you!:wink:
Kurt
 
Last edited:
rockets said:
Hmm, I'm not sure yet.
The hardest part is trying to find a cheap, hollow 29mm conical nose cone!!
Thanks,
Click to expand...

You could roll your own with paper. There are methods to increase strength, such as soaking in CA.
 
ksaves2 said:
Ahhhh, Remember this is a young man venturing into this realm. I recommend keeping it simple for the first time. An Apogee Aspire clone would be simple, cheap and break Mach for him on a G80-10. With an SU motor, lose it and no big deal. This fellow may be of limited means and his youth means there is plenty of time ahead to plan big. And Oh, how my plans
have changed by observing others and myself coming to the self-realization that some of what we do may look easy but getting it pulled off successfully can be quite hard.

Losing a hard earned project right off can be very disheartening and going fast on a minimal investment can soften the blow. Kurt
Click to expand...

I recently wrapped up a pair of scratch built aspires- I got the parts for 2 for the price of 1.
apogee has a pretty good video on making mylar streamers, which I purchased a mylar survival blanket for about $3 on amazon. got a few streamers so far and material for quite a few more.
total weight without motor-2.6 oz and 2.8 oz. ones a 3fin and ones a 4 fin.
 
dhbarr said:
Check out Easy Research Rocketry, they were offering up a conical made to fit ( IIRC ) BMS 29mm MMT. Hard to get more MAD than that.
Click to expand...

I was, and I can. Just not a standard offering anymore.
 

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