Going for 100,000 Feet

Well. it's been a while since I posted on this project. Other things to do like take a trip to Nebraska to see the total eclipse ... Awesome. I also worked on a design for an 8x Upscale Alpha. But it's time to get back on this. There had been some discussion about skipping Re and going to Mi, but I decided to stick to my original plan. My hope is to take this to Argonia, KS in the summer of 2018.

I opted to go with the Complex K rocket, which is the "Re" design. It will be named "The Golden Sundrop." Ordered parts from Madcow over the weekend and took advantage of the 25% off Black Friday sales. This will also be thin-wall filament wound FG. Sustainer has a 38mm airframe with a 5:1 VK Nose Cone. I bought a 54mm 5:1 Ogive nose cone that I will cut for the transition. Fins will be tip to tip FG.

There are 3-4 motor combinations that all get me north of 40,000 feet in RAS Aero sims. I'd like for it to break Mach 2, but stay under Mach 2.4. Fiberglass can survive about Mach 2.5 but after that you start to stretch your luck. The least damaging flight is a K400 booster and a J150 sustainer. The flight of Do had a 3-second delay between separation and booster ignition. This will have a much longer delay. That gets me a lot more altitude.

This will also need added electronics. It will need a GPS Altimeter, and I think I will use a BRB 70 cm GPS transmitter. I can connect it to a computer or cell phone and use Google Earth to track it. Thought about the Kate system but it is extremely pricey, and with so many people using it, it is starting to get annoying. I will again use the Raven Altimeter to control deployment. It has a number of safety features in it that prevents ignition of the sustainer if it is not ascending or pointed the right direction.

This rocket will separate via a timer in the booster stage instead of with the Raven in the sustainer. I will also need a tracker in the booster since it will go a lot higher. I think I will use a 2-event timer to do separation, then main chute deployment. The Motor charge can do the booster apogee deployment.

The fins are also a little larger giving this a lot more stability. The sustainer fins are about 1.2x the airframe diameter and the booster fins are about 1.1x.

The biggest issue I have is deployment at apogee. Most would say that BP deployment at 40,000' is not advisable, but I have not seen any CO2 systems that go into an airframe smaller than 54mm. My sustainer will be 38mm. Thoughts I have are 1 - using BP but increasing the amount of powder to 4x what is needed so that the powder that actually burns will be sufficient. or 2 - With the Raven not needing to separate, I can add a second charge that would fire as a backup at 20,000' where BP is more effective. I would need a much longer shock cord and a streamer to slow it down.

Here is the most current design. Feedback is welcome.

This sounds like an awesome project, I hope you take it to Argonia to fly it! Subscribed

Do they have 100k at Argonia? Wow. Kurt

ksaves2 said:

Do they have 100k at Argonia? Wow. Kurt

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No. It is 50K. The second rocket in this project will "only" hit 43K.

If you contain the black powder fully it should create a mini explosion even at such altitude.

I believe people have had good success at very high altitude with containing the bp charge in surgical tubing which is tied off at each end and sealed. Thus the charge bringing up its own pressurized air supply. BANG and all the combustion gases you get.

ksaves2 said:

Do they have 100k at Argonia? Wow. Kurt

Click to expand...

No. It is 50K. The second rocket in this project will "only" hit 43K.

jderimig said:

I believe people have had good success at very high altitude with containing the bp charge in surgical tubing which is tied off at each end and sealed. Thus the charge bringing up its own pressurized air supply. BANG and all the combustion gases you get.

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That's a good idea.

For a UTC SEDS flight we compressed charges in 9/32" autozone vac tube, end fits FireWire perfectly, and seal it. Trim tube to length. You don't want lose powder at all. We were using 0.6-0.7grams in our small applications. We were looking at 20,000ft plus on L-1 multistage. Went with UROC over Argonia. But Argonia was on the radar as alternates. UROC was open to metal airframes and other construction tactics like through wall fin joints. HVAC tape is extremely sticky if you need to make containers lighter, but it took more practice to wrap right for reliability.

If you find a mountainous launch site you can take advantage of a higher launch elevation with less air density also. You can even design a nozzle for back pressures not near sea level and increase thrust but that's harder to do. Always little tricks.

Get a box of Firewires and experiment.

EeebeeE said:

The other option would be to glue the case into the airframe.

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Cotronics 4700 works wonderfully for this since it excels at higher 600F thermal loads. It is an expensive epoxy and it need oven cure.

EeebeeE said:

That's a good idea.

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Look up Jim Jarvis. He did this very thing.


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BDB said:

Look up Jim Jarvis. He did this very thing.


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Click to expand...

And Jim has an even better method he recommends for using BP in high altitude deployments not involving surgical tubing iirc.

Tony Alcocer did some research and settled on clear vinyl tubing. I used it on my flight to 37k and had no problems with ejection.

jderimig said:

I believe people have had good success at very high altitude with containing the bp charge in surgical tubing which is tied off at each end and sealed. Thus the charge bringing up its own pressurized air supply. BANG and all the combustion gases you get.

Click to expand...

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Andrew_ASC said:

Went with UROC over Argonia. But Argonia was on the radar as alternates. UROC was open to metal airframes and other construction tactics like through wall fin joints.

Click to expand...

Argonia is the closest to me in Western, NY.

ChrisAttebery said:

Tony Alcocer did some research and settled on clear vinyl tubing. I used it on my flight to 37k and had no problems with ejection.

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I think Tony and I would agree that we shouldn't be doing high altitude deployment with surgical tubing. In a near vacuum, and in a large container (i.e., worst case conditions), only about 10% of the powder burns. If there is more air, and if the charge is inside of a packed deployment section, then more of the powder will burn and surgical tube containment can work - but not because of the surgical tubing.

The method I use, which is yet again documented in the attachment, results in 100% combustion of the powder under any conditions. One advantage of the approach is that, since everything burns, you can do valid ground testing. The charge will work the same way at 100K feet as it does on the ground. One of the disadvantages, though, is that the charge is very energetic because all of the power burns in a short time frame. I call it "deployment by shotgun" (Tony would agree with that, too), and the structure that holds the charge container needs to be pretty strong.

Tony is working on a method that is conceptually similar, but that could be less energetic. This is done with the vinyl tubing. He might have posted some information on this, but I'm not sure about that.

Jim

View attachment Article on high altitude deployment charges_May 2013.pdf

I agree with what Jim says. Surgical tubing "has" worked, but occasionally it does not. There seems to be some 'magical' aspect that needs to be present for it to always work. Surgical tubing has been used to 104K.

Jim is right about his method being energetic!

I played around with his concept and got it to where I felt comfortable with it. There are a couple of post around on the "concept principles"
https://www.rocketryforum.com/showthread.php?136898-Hermetically-Sealed-Ejection-Cap

Here is a photo of what I ended up coming up with and use.


I've not done any really high altitude flights with it yet 37K so far. But in the vacuum tests it consumes 100% of the BP.

Tony

Tony, thanks for sharing--great picture. I have not used surgical tubing and curious about a few things. First, and perhaps Jim Jarvis refers to this above, but it seems this deployment charge would be fairly directional and need some sort of orientation keeping method. How do you have the charge placement 'mounted' within the airframe? Second, in your testing, did you try other types of surgical tubing other than vinyl? Silicone tubing comes to mind and may burst in the middle (omnidirectional) before the ends, but not sure if it would be as good in a vacuum. Lastly, is the BP used 4F? I would think it would have to be as fast burning to get a complete burn as you're getting.

BTW, really appreciate experienced guys like you and Jim Jarvis so willing to share your lessons learned, often the hard way, to make others more successful. It's things like this that make the rocketry community what it is to me.

The secret to the method is the open portion of the tube (in Tony's pic, the lower section of dog barf). When the initial combustion gases are passing through this section, the pressure increases a little, which causes more powder to burn, more pressure, more powder, boom. Another way to look at it is that the powder burns before it has time to leave the tube.

When I first started looking at this, I tried a "one-sided" charge where all of the gases came out one end of the tube. I was using a metal tube, and the net result of this was that the tube was turned into something else (specifically, a bullet). I believe Tony's design is also one-sided, but the lighter vinyl tube doesn't make a very good bullet, thus, a better approach from that perspective. I was a little surprise when Tony was testing this that the tube didn't split, and as long as it doesn't, it will work.

I also came up with a double-sided design, which I called a "T" charge, where combustion gases come out of the two opposing ends. It works fine, and I have used it on high altitude flights. However, the device is pretty long and takes up space. Therefore, I just use a well-supported, one-sided approach. I'm not sure if the orientation of Tony's charge matters (i.e., does it need to be aimed away from the wall of the air frame). If it matters, then the approach I use has the advantage of aiming the charge down the axis of the tube.

Jim

Hmm, lamp nipple pipes for ebay tying could easily be used for long dwell times.

Maybe cut in 2-10% of fast double base pistol powder and sub null b for 4f... *Sigh* add duplex loads to the to-test pile

Tony,

Great photo. In my mind I had thought of something similar, and this gives me confirmation that my idea were at least plausible.

I hadn't included the dog barf and instead thought of encapsulating an "electric firecracker" inside tubing like this. The dog barf would work better because it still allows air inside, and at the same time still contains the blast better.

Can this be scaled down? I only need about 0.3 grams of BP at sea level to separate the booster and payload.

The only thing I might want to do is to criss-cross electrical tape across the hot glue plug, then wrap more electrical tape around the tube to hold down the ends of the criss-crossed pieces to prevent the plug from being prematurely blown out.

JimJarvis50 said:

I believe Tony's design is also one-sided, but the lighter vinyl tube doesn't make a very good bullet, thus, a better approach from that perspective. I was a little surprise when Tony was testing this that the tube didn't split, and as long as it doesn't, it will work.

Click to expand...

Jim, do you have a photo of your "T" design?

It seems to me that a section of air or vacuum hose that is rated to 100 PSI is probably very effective because the devices at both ends to contain the explosion are most likely going to be weaker and give way first before the tube splits.

I think I know someone with access to a vacuum chamber. The thing for me to do is to make a few different configurations and test them.

Jim and Tony, have either of you tested with polyethylene tubing or the fiber reinforced vinyl tubing?

I’ve run a couple of ground tests with poly tubes and it works great. It’s stiffer and stronger than vinyl so less likely to rupture out the sides. I have not flown a charge with poly yet, but hope to do so soon.


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Look in the end of the PDF he posted above. Kurt

EeebeeE said:

Tony,



The only thing I might want to do is to criss-cross electrical tape across the hot glue plug, then wrap more electrical tape around the tube to hold down the ends of the criss-crossed pieces to prevent the plug from being prematurely blown out.

Click to expand...

I did most of my testing with the end of the tube wide open. It is the length of the open tube, and not the plug, that contains the charge and causes the powder to burn. It is important to realize this. I seal the end of the tube in my device to keep the original atmospheric air in the tube. This is because the ematch itself works better if there is some air present when the match fires. Otherwise, a plug to restrain the combustion gases is not needed or wanted at the end of the tube. You just need some wadding or dog barf to hold the powder at the correct location.

Jim

Jim and Tony have the Right Stuff. I'll add a few comments to summarize what I've been saying for probably 15 years now.

The dwell time for full combustion of the BP is most important feature of any of the schemes. The time contained within a moderate volume allows for the most heat transfer for combustion... therefore the most gas generated.

Too little containment spreads unburned BP before full combustion. This is worse at lower ambient pressure at high altitude.

Too much containment will create high pressure and high burnrate. This seems desirable, but has two side effects: it creates a bomb or bullet, and it could also burst, spreading unburned power before complete combustion.

The open length of tube provides a flute effect: the diameter of the pipe and speed of the gasses creates a back-pressure for containment. No plug needed, but some light filler and tape keep the powder from dumping out during the flight.

The plastic tubing containment is less reliable due to chances that the tube burns through too soon. And there are so many types of tubing that you can never be sure of the characteristics. I have found that soft latex surgical is very good. See: https://www.mcmaster.com/#5234k991/
It has a thick wall, stretches without bursting, and has good quality control compared to vinyl tubing.
I've used a similar setup to Tony's picture, but double zipties at the ends. Use at least 5x the length of tubing as BP. Also, do not clamp down the tubing in the middle. It sounded like a good idea at the time.

jsdemar said:

I have found that soft latex surgical is very good. See: https://www.mcmaster.com/#5234k991/
It has a thick wall, stretches without bursting, and has good quality control compared to vinyl tubing.
I've used a similar setup to Tony's picture, but double zipties at the ends. Use at least 5x the length of tubing as BP. Also, do not clamp down the tubing in the middle. It sounded like a good idea at the time.

Click to expand...

It is very likely that I would have tested that tubing, and tubing with even thicker walls. None of the tubes worked under my worst-case conditions. I assume that you are zipping the ends shut so that the tubing splits? If this is the case, then the primary difference of what you are describing is using a surgical latex tube that is 5x times the length of the BP versus 1x times the length of the BP. I wonder if that's Tony's magic?

Jim

You will need more than .3g if you use Tony's method. Blowing the plugs out of the tubing will burn up some of your energy. I wound up using .5g in a 3" ID x 3.5" bay with 2x 2-56 shear pins.

https://www.rocketryforum.com/showthread.php?137544-Wildman-Blackhawk-75&p=1726108#post1726108

EeebeeE said:

Tony,

Great photo. In my mind I had thought of something similar, and this gives me confirmation that my idea were at least plausible.

I hadn't included the dog barf and instead thought of encapsulating an "electric firecracker" inside tubing like this. The dog barf would work better because it still allows air inside, and at the same time still contains the blast better.

Can this be scaled down? I only need about 0.3 grams of BP at sea level to separate the booster and payload.

The only thing I might want to do is to criss-cross electrical tape across the hot glue plug, then wrap more electrical tape around the tube to hold down the ends of the criss-crossed pieces to prevent the plug from being prematurely blown out.

Click to expand...

EeebeeE said:

Can this be scaled down? I only need about 0.3 grams of BP at sea level to separate the booster and payload.

Click to expand...

Thinking outside the box, if you need only a small volume of powder to create the pressure would a "cluster" of bare ematches work? No containment or tubing required.

A series-parallel combination of 6 to 8 ematches might do the trick. Especially those energetic Chinese ones.

I am experimenting with 3D printed explosive bolt concepts and just one Chinese ematch blows those apart.

would a "cluster" of bare ematches work?

Interesting idea:
How about surgical tubing with a match at each end?
Or a brass tube with matches at each end held in with dog barf.
All BP particles would have to pass the plasma-ball.....

FredA said:

would a "cluster" of bare ematches work?

Interesting idea:
How about surgical tubing with a match at each end?
Or a brass tube with matches at each end held in with dog barf.
All BP particles would have to pass the plasma-ball.....

Click to expand...

The weakness of black powder is that it is Black Powder. The powder has a hazard of dispersing before we can burn it and get to release its energy. So we devise all these work arounds to prevent this.

How about Fred's tube, a pyrodex pellet, and a rod in the tube with a piston at the end of it. If you light the pellet it will all burn, guaranteed. Works in muzzle loaders.