Mach 2 attempt

[Joey Draney]

Any thoughts on this? It’s a cardboard kit from apogee components that I’ve fully fiberglassed with 2 layers of 8.9 ounce fiberglass on the fin can and 2 layers of 1.5 ounce on the rest of the body tube. It’s 29 minimum diameter and weighs just about 75 grams with no motor. The attempt is with an aerotech i205. My goal is essentially to see how small of a rocket i can get to Mach 2. Does anyone think it will survive?

 

[Art Upton]

I don't know... I did fly an Estes PSII 2.5 rocket to 880 mph with no mods just Gorilla Glue on the fin tabs to the motor tube and sealer to the body tube slots on an I205 twice at Jean dry lake...

Your Fins will be the part you need to worry about as at Min Diameter you have no TTW tabs to beef up the torque strength...

Edit: I doubt it will ever get to Mach 2

 

[Handeman]

It should get close, but probably won't break mach 2. But who knows...
How are you measuring the speed? Baro type altimeters are notoriously wrong about speed.

 

[OzHybrid]

Gut feeling says you'll lose a fin. The wall thickness of your glassed cardboard tube is only 0.5mm This doesn't give you much to attach a fin to.
Norm

 

[Joey Draney]

It should get close, but probably won't break mach 2. But who knows...
How are you measuring the speed? Baro type altimeters are notoriously wrong about speed.

Haven’t flown it yet. This is just rocksim data with my site altitude and conditions put in.

 

[Joey Draney]

Gut feeling says you'll lose a fin. The wall thickness of your glassed cardboard tube is only 0.5mm This doesn't give you much to attach a fin to.
Norm

Definitely a possibility. Worth a try for sure though, It’d be one hell of a flight

 

[Joey Draney]

Haven’t flown it yet. This is just rocksim data with my site altitude and conditions put in.

I can’t measure the speed with anything because it would add to much weight to put any sort of electronics in it. This is sort of just a yolo flight.

 

[Handeman]

I can’t measure the speed with anything because it would add to much weight to put any sort of electronics in it. This is sort of just a yolo flight.

Just a guesstimate? Then I guess you'll hit your mark.

If you don't loose a fin, you might get a zipper. I'm not sure the delay on the motor will be long enough to deploy at a slow speed.

 

[Joey Draney]

Just a guesstimate? Then I guess you'll hit your mark.

If you don't loose a fin, you might get a zipper. I'm not sure the delay on the motor will be long enough to deploy at a slow speed.

It’s barely long enough it called for 14 second delay and it’s got max 14 second delay

 

[OzHybrid]

Mach 2 is faster than most bullets. If it heads toward you, you might not have time to get out of the way. You will probably lose a fin.
Ha Ha and oh **** are close cousins..... If you don't think it will survive, don't launch it. You'd just be endangering others. yolo.

 

[tfish]

My 13 year old son built a fat boy for an I435. IIRC it flew at over 900 mph the nose cone and body tube are stock with fiberglass wraps..
this was about 22 years ago..

see.. https://www.rocketryforum.com/threa...-nosecone-via-motor-eject.178916/post-2407850

https://www.rocketryforum.com/threads/mega-mosquito-as-a-38mm.61288/post-643354



why so thick of glass" That's going to be hard to keep if formed around a 29mm body..I'd go with some 1-2 oz and several layers..do some test layups and see how they "feel".

yes it can be done...you might get away with using 29mm phenolic motor tube unglassed.


Tony

 

[Joey Draney]

My 13 year old son built a fat boy for an I435. IIRC it flew at over 900 mph the nose cone and body tube are stock with fiberglass wraps..
this was about 22 years ago..

see.. https://www.rocketryforum.com/threa...-nosecone-via-motor-eject.178916/post-2407850

https://www.rocketryforum.com/threads/mega-mosquito-as-a-38mm.61288/post-643354



why so thick of glass" That's going to be hard to keep if formed around a 29mm body..I'd go with some 1-2 oz and several layers..do some test layups and see how they "feel".

yes it can be done...you might get away with using 29mm phenolic motor tube unglassed.


Tony

Thanks for the suggestions, I am also 13! I did several test layups on old body tubes I had and then did the real thing and it turned out great. It was 2 layers of 1.5 ounce on the body tube but I wasn’t confident in the fins so I did 2 layers of 8.9 ounce and it’s extremely strong. I just don’t know about Mach 2 strong. Also I’m not quite sure what to do about the launch lug/Rail buttons. Do minimum diameter rail buttons exist?

 

[tfish]

Do minimum diameter rail buttons exist?

yes..mini and micro buttons..
out of a tower works to (yesterday 3 of the high school kids I work with did a min dia with a J415 to a tad over 13K)
buttons hold up pretty well.



sometimes they are single use!

"Things" don't start getting rough until about mach 2.7. You do need good solid build techniques and glues..through 2.6. Then you'll need professional level.

a couple years back I did a build to show how basic good techniques and even boat epoxies can work well..

https://www.rocketryforum.com/threads/my-next-project.19534/
Tony

 

[OzHybrid]

Hi Joey,
This is an impressive goal for a 13-year-old. Is anyone assisting you? Unfortunately, legally you cannot be in possession of the motor you specified. Is there a Tripoli or NAR Level 1 certified adult assisting you?

 

[Joey Draney]

Hi Joey,
This is an impressive goal for a 13-year-old. Is anyone assisting you? Unfortunately, legally you cannot be in possession of the motor you specified. Is there a Tripoli or NAR Level 1 certified adult assisting you?

Yes my mentor is John Jameson, I’ve flown multiple rockets with him surpassing Mach 1 and decided I’d try and push the limits a little. I’ve also got a 3 inch punisher that’s flying on an i600.

 

[Joey Draney]

Yes my mentor is John Jameson, I’ve flown multiple rockets with him surpassing Mach 1 and decided I’d try and push the limits a little. I’ve also got a 3 inch punisher that’s flying on an i600.

I wish I could get my L2 but I’ll have to wait a while. My mentor and other l3 certified members of my club have said that would easily be able to but obviously it’s not possible yet.

 

[OzHybrid]

My 13 year old son built a fat boy for an I435. IIRC it flew at over 900 mph the nose cone and body tube are stock with fiberglass wraps..
this was about 22 years ago..

see.. https://www.rocketryforum.com/threa...-nosecone-via-motor-eject.178916/post-2407850

https://www.rocketryforum.com/threads/mega-mosquito-as-a-38mm.61288/post-643354



why so thick of glass" That's going to be hard to keep if formed around a 29mm body..I'd go with some 1-2 oz and several layers..do some test layups and see how they "feel".

yes it can be done...you might get away with using 29mm phenolic motor tube unglassed.


Tony

The old MachBuster was thickish phenolic, through the wall fins, fiberglass fins. I found the bits recently having opened the packet 20 years ago and scattered the parts to the 4 winds.

 

[OzHybrid]

I wish I could get my L2 but I’ll have to wait a while. My mentor and other l3 certified members of my club have said that would easily be able to but obviously it’s not possible yet.

Sounds like you've got good support, and that makes a massive difference to the success of this kind of project. Make sure your fins are stiff and well attached with a quality fillet.
All the best with the flight and give us pictures.
Norm

 

[Joey Draney]

Sounds like you've got good support, and that makes a massive difference to the success of this kind of project. Make sure your fins are stiff and well attached with a quality fillet.
All the best with the flight and give us pictures.
Norm

Thanks! Yea I’ve got about 3/8 inch radius rocketpoxy fillets and 2 layers of 8.9oz fiberglass on the fin can. I’ll send a video in a week at the launch. Hopefully it all holds up.

 

[OzHybrid]

Thanks! Yea I’ve got about 3/8 inch radius rocketpoxy fillets and 2 layers of 8.9oz fiberglass on the fin can. I’ll send a video in a week at the launch. Hopefully it all holds up.

Just don't blink when you launch it....

 

[Joey Draney]

Just don't blink when you launch it....

Funny you say that, That’s the name of the rocket. “Don’t blink”

 

[OzHybrid]

A silver mylar streamer will give you good high altitude visibility. It glints in the sun. Make sure there are no power lines as a silvered mylar streamer can cause a short across HV lines and once the air is ionised, lots of current flows. YouTube mylar balloon and power line.
Otherwise, a flouro pink or orange chute are best.
Finding it afterwards is going to be interesting. One of the techniques we've used is a laser on a tripod. Follow the rocket down and point the laser at it on the tripod. Lock it off and you can walk the laser line. Use a safe laser.
Norm

 

[Joey Draney]

A silver mylar streamer will give you good high altitude visibility. It glints in the sun. Make sure there are no power lines as a silvered mylar streamer can cause a short across HV lines and once the air is ionised, lots of current flows. YouTube mylar balloon and power line.
Otherwise, a flouro pink or orange chute are best.
Finding it afterwards is going to be interesting. One of the techniques we've used is a laser on a tripod. Follow the rocket down and point the laser at it on the tripod. Lock it off and you can walk the laser line. Use a safe laser.
Norm

Yea the recovery will definitely be difficult. 8500ft is the projected altitude, it’s not the end of the world if I don’t get it back, there’s always more rockets to fly! Thanks for tip

 

[Joey Draney]

I am using a very reflective streamer and I made it 3x the length so it will be easier to see.

 

[manixFan]

To follow up what Tony (tfish) said, below Mach 2.5 things are not too bad. In my personal experience, good fin alignment is key to keeping them attached and the rocket in one piece, assuming they are the correct shape and material. Also based on experience, with a 29mm or 38mm rocket that's going past Mach, a tower is really the way to go. The increase in frontal area as a percentage of original body tube area is obviously a lot greater when you put a 1010 rail button on a 29mm body tube vs. a 54mm rocket or larger. Buttons are a speed killer with small diameter rockets. It's possible fly-away rail guides will work, but again, based on personal experience, I've had trouble with them and small diameter rockets that break Mach very soon after launch.

But honestly, if you don't have an altimeter or tracker, I'm not sure what the point will be. You won't know what the actual speed was or likely even recover the rocket. It's easy to build a rocket that goes to Mach 2 if you don't get it back! I've used highly reflective mylar streamers in the past but above a few thousand feet they don't seem to be much use in tracking the rocket. At over 8,000' you'd need a streamer far larger than you can fit into a 29mm body tube in order for it to be visible. There are very small and lightweight (less than 5 grams) radio beacon trackers that you can use for tracking, but you'll need to find someone with the gear and experience.

Good luck and keep working on it. You've got plenty of time to figure it out and get it right.


Tony

PS: as an experiment, take the streamer you intend to use and attach it to a pole so it waves freely. Then have a helper wave it while you move away from it, and note when you lose sight of it. Based on my tests, it will be far short of the 8,000' altitude you expect to reach.

 

[OzHybrid]

I might ask you to review my next rocket.....

 

[Joey Draney]

To follow up what Tony (tfish) said, below Mach 2.5 things are not too bad. In my personal experience, good fin alignment is key to keeping them attached and the rocket in one piece, assuming they are the correct shape and material. Also based on experience, with a 29mm or 38mm rocket that's going past Mach, a tower is really the way to go. The increase in frontal area as a percentage of original body tube area is obviously a lot greater when you put a 1010 rail button on a 29mm body tube vs. a 54mm rocket or larger. Buttons are a speed killer with small diameter rockets. It's possible fly-away rail guides will work, but again, based on personal experience, I've had trouble with them and small diameter rockets that break Mach very soon after launch.

But honestly, if you don't have an altimeter or tracker, I'm not sure what the point will be. You won't know what the actual speed was or likely even recover the rocket. It's easy to build a rocket that goes Mach 2 if you don't get it back! I've used highly reflective mylar streamers in the past but above a few thousand feet they don't seem to be much use in tracking the rocket. At over 8,000' you'd need a streamer far larger than you can fit into a 29mm body tube in order for it to be visible. There are very small and lightweight (less than 5 grams) radio beacon trackers that you can use for tracking, but you'll need to find someone with the gear and experience.

Good luck and keep working on it. You've got plenty of time to figure it out and get it right.


Tony

Thanks for the comment! Yea I’m most likely going to launch it out of a tower. if I get this one back in one piece I’ll launch it again and if not i do have the materials to build another one and I can revise my Building techniques for a better launch. I’m terms of tracking I’d like to see what happens with this launch before I put tracking in it just in case I have a failure (fin shred, body tube shred) I won’t loose a tracker.

 

[Sandy H.]

Thanks for the comment! Yea I’m most likely going to launch it out of a tower. if I get this one back in one piece I’ll launch it again and if not i do have the materials to build another one and I can revise my Building techniques for a better launch. I’m terms of tracking I’d like to see what happens with this launch before I put tracking in it just in case I have a failure (fin shred, body tube shred) I won’t loose a tracker.

Maybe a personal alert/screamer at least? Things that make noise might help recover and would be cheap. Never tried the type of flight you're doing, so maybe I'm wrong - just a thought.

 

[Joey Draney]

Maybe a personal alert/screamer at least? Things that make noise might help recover and would be cheap. Never tried the type of flight you're doing, so maybe I'm wrong - just a thought.

A good suggestion! I’ve never tried one in any of my flights I guess I’ve just never thought about it. I might give it a try in the future.

 

[teepot]

Interesting name. I also have a Don't Blink. a 29mm MD I built for a G80-13. ThrustCurve says 6000'. It's going to have a tracker though.