Great BALLS of Fire 2.0

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Wilson, I'm kind of curious about the sizes of the charges you are using. In my 3" rockets, I don't believe I've ever used more than about 1.3 grams of BP in any of them. I assume you've ground tested your 3 and 6-gram charges (glove finger charges?) and that they give appropriate deployment for your rocket? If yes, I wonder if you're actually getting all of the powder burned? Or, perhaps you're just a member of the "blow it out or blow it up" club.

Jim

Hi Jim - yes, I ground tested starting with a 1.5 gram charge inside a glove fingertip which was not sufficient to cut my shear pins. I am using 3 x 4-40 nylon screws on the nosecone which is probably way too much anyways...
Working my way up from there I found that 3 grams was plenty to deploy the nosecone "with authority." The entire charge was certainly burning. I'm using a 25' harness so plenty of slack there, as well. As for the 6 gram backup, well that's obviously way too much for my rocket. But I'm plenty nervous about this flight and the last thing I need is it coming in ballistic - hence if the primary charge doesn't do it, then the backup better should.

And yes, I am certainly in the "blow it out, or blow it up" club.
 
Flew this on an Aerotech L1150R this past weekend for a test flight. Awesome boost, the red flame was about as long as the rocket!! :D

Recovery wasn't perfect - I think I need to rethink my drogue deployment. I didn't see the entire recovery so I can't be certain what happened, but long story short it would seem as though I blew up my main chute on accident. Jim, I think you were exactly right about my charges being too big. The drogue charges were located right below the main chute, which stripped on deployment. The Tender Descender worked perfectly, but I think my drogueless descent was way too fast.

More to come later...
 
Hi folks, sorry for the delay...

I hadn't came up with a name for this rocket yet, so just for giggles I put "To be named later" on the flight card. It flew on an L1150R to just over 15K, which was higher than I was expecting.

Thanks to Rob Appleton for the pad photo (and for help prepping on the hill).
IMG_2633.JPG

As per my previous post, the boost was perfect. I saw both the drogue charges deploy, but not much after that. I'll have some more photos and altimeter data to post later today, but here is what I THINK happened:

  • The drogue charge cut the shear pins as planned and separated the nosecone, however since they were located right below the bundled main chute, the charges severely burned/damaged the chute.
  • Rocket was descending too fast since I flew it drogueless.
  • When the Tender Descender went off at 800' the main chute was already too damaged to be of any use, which then stripped on deployment.
This past weekend I have been getting this rocket ready for it's flight at BALLS. It will fly on an Aerotech M1550R to about 25K. For this flight I will be making the following changes:

  • Add a drogue chute. (24"?)
  • Use more Nomex to protect the main chute. (45" octagon)
  • Use smaller drogue charges.
  • Place drogue charges further away from main chute.
Any further thoughts?
 
Also, here is a video of the launch. Skip ahead to 2:49.
https://picasaweb.google.com/104803...hkey=Gv1sRgCIr86a2aoqvZAw#6053984990542611458

While listening to the radio the other day, I figured out the perfect name for this vehicle:
"Great BALLS of Fire!"

Get it? ;)

This of course means my color scheme will be red and orange. Originally I wasn't sure if I wanted to paint it before BALLS, but I then remembered it only took me a weekend to paint Code Blue. Hence, I'll go shopping for paint this week. I'm using Limco Supreme Plus, a catalyzed urethane-based paint. (Exact same stuff I shot last time.)
 
Good luck, wish I could be there. Flight reports so far on these fin cans have been exceeding simulated altitudes by 5-10% despite the general opinion that they are "draggy" because of the screws.
 
Good luck, wish I could be there. Flight reports so far on these fin cans have been exceeding simulated altitudes by 5-10% despite the general opinion that they are "draggy" because of the screws.
Thanks Mike! Indeed, my L1150R flight went about 2,000' higher than simulated. We'll miss you at BALLS this year - any idea when Mr. Scary might fly again?
 
Ryan an David went to 63K at Mudroc. Those charges were 3 grams IIRC and we used 2 zip ties on each end. The tube we used was https://www.mcmaster.com/#5234k99/=tcun2z

And 57k the year before. The shear pin scheme was also designed to hold atmospheric pressure with a SF of 2 to mitigate any drag separation in case proper venting of the bay was not achieved. So the required push was not insubstantial. Surgical tubing is pretty great.
 
And 57k the year before. The shear pin scheme was also designed to hold atmospheric pressure with a SF of 2 to mitigate any drag separation in case proper venting of the bay was not achieved. So the required push was not insubstantial. Surgical tubing is pretty great.

But you can instead seal the parachute bay, and not require surgical tubing...
 
But you can instead seal the parachute bay, and not require surgical tubing...

If I had wanted to add weight and complexity I would have done that.

Don't get me wrong, I like the idea, but surgical tubing works.
 
Here's what I'm planning to try for charges on my ~40k flight at XPRS.
Are you flying the M685W?

As to surgical tubing - I just realized that my local Bi-Mart carries it, so that is what I'll be using for my drogue charges. I test fired a charge in open air and it seems to fire much more aggressively (i.e., "POP!") than a glove fingertip.
 
That's the plan. I mailed my 75/7680 case to Bruno's yesterday. My rocket parts break down to reasonable lengths, but the case was a little too long for my luggage. Hopefully it's waiting for me tomorrow when I get there.

Are you flying the M685W?

As to surgical tubing - I just realized that my local Bi-Mart carries it, so that is what I'll be using for my drogue charges. I test fired a charge in open air and it seems to fire much more aggressively (i.e., "POP!") than a glove fingertip.
 
That's the plan. I mailed my 75/7680 case to Bruno's yesterday. My rocket parts break down to reasonable lengths, but the case was a little too long for my luggage. Hopefully it's waiting for me tomorrow when I get there.

Great! Have fun out there - I hear the weather is perfect on the playa right now.
 
Are you flying the M685W?

As to surgical tubing - I just realized that my local Bi-Mart carries it, so that is what I'll be using for my drogue charges. I test fired a charge in open air and it seems to fire much more aggressively (i.e., "POP!") than a glove fingertip.

I did a bit more testing on high altitude charges. One question I was trying to answer is how well the tubing charges work at an intermediate altitude (say around 45K). Didn't get quite the answer I was expecting. A video is attached. This one won't go viral, but if you're considering tubing charges, you might take a look.

[video=youtube_share;2b3_JlbAbKQ]https://youtu.be/2b3_JlbAbKQ[/video]

Jim
 
Thanks Mike! Indeed, my L1150R flight went about 2,000' higher than simulated. We'll miss you at BALLS this year - any idea when Mr. Scary might fly again?

NXRS 2015. The altimeter I was using screwed me out of my only flight this year. Anybody that wants to know what altimeter not to buy just ask me in person sometime.
 
I did a bit more testing on high altitude charges. One question I was trying to answer is how well the tubing charges work at an intermediate altitude (say around 45K). Didn't get quite the answer I was expecting. A video is attached. This one won't go viral, but if you're considering tubing charges, you might take a look.

Thanks for the video! Look forward to meeting you next weekend.

NXRS 2015. The altimeter I was using screwed me out of my only flight this year. Anybody that wants to know what altimeter not to buy just ask me in person sometime.
Damn!
 
Wilson,

This project is going to pull a lot more G's than your Comp4 on a 1297.

Are you SURE about the push-button switches? Can they handle the G's they're going to see?
 
I did a bit more testing on high altitude charges. One question I was trying to answer is how well the tubing charges work at an intermediate altitude (say around 45K). Didn't get quite the answer I was expecting. A video is attached. This one won't go viral, but if you're considering tubing charges, you might take a look.

[video=youtube_share;2b3_JlbAbKQ]https://youtu.be/2b3_JlbAbKQ[/video]

Jim

Jim, thanks again for your testing in the deployment charge area. As we have discussed in the past, kind of by chance, I have been using high containment charges (high L to W ratio metal containment) for some time now. In my case though, I build them "single-ended" which seems like it would be more effective with containment in Z-plane also allowing gases to flow only one direction. What are your thoughts on that? Why did you pursue the T-structure which allows initial gas to expansion in two (opposite) directions?

BTW, all the best on your BALLS flight!!!


Sent from my iPad using Rocketry Forum
 
Jim, thanks again for your testing in the deployment charge area. As we have discussed in the past, kind of by chance, I have been using high containment charges (high L to W ratio metal containment) for some time now. In my case though, I build them "single-ended" which seems like it would be more effective with containment in Z-plane also allowing gases to flow only one direction. What are your thoughts on that? Why did you pursue the T-structure which allows initial gas to expansion in two (opposite) directions?

BTW, all the best on your BALLS flight!!!


Sent from my iPad using Rocketry Forum

Actually, I use the one-sided approach as well. I've posted a write-up on the original testing I did, which included an update on the one-sided approach. The T approach works too, and has the advantage of less kick. It doesn't have to be attached to anything (other than the harness for example). The one-sided approach, as I'm sure you know, has to be attached to something pretty solid.

Jim
 
Actually, I use the one-sided approach as well. I've posted a write-up on the original testing I did, which included an update on the one-sided approach. The T approach works too, and has the advantage of less kick. It doesn't have to be attached to anything (other than the harness for example). The one-sided approach, as I'm sure you know, has to be attached to something pretty solid.

Jim

Got it.
 
Likewise! The easiest way to find me is to wait until Tony walks by with a handful of black rocket pieces. Then, just follow him!

Jim
funny! But true!

Tony
Very funny indeed. :)

Wilson,

This project is going to pull a lot more G's than your Comp4 on a 1297.

Are you SURE about the push-button switches? Can they handle the G's they're going to see?
They should, plus the switches are mounted in a way that G's on boost would not (in theory) trigger them.

As for the Comp 4. That will be flying on a CTI M840 this weekend!
 
As many of you heard, this flight (and also the only flight I got to do at BALLS, thanks to the weather) was less than optimal. Some photos first...

IMG_2656.jpgIMG_2660.jpgIMG_2661.jpg
IMG_2663.jpgIMG_2664.jpgIMG_2662.jpg

IMG_2667.jpg

IMG_2698.jpg

I flew it on the Aerotech M1550R like I had planned. When I pushed the button, it took off at a fairly sharp angle. I originally thought it had just weathercocked, but upon further inspection I had dropped the aft rail button on takeoff. (It was still inside the rail after launch.) Need to rethink my attachment method there, as well...

A few seconds after burnout, we heard a "bad noise" from the ground. Hard to identify what it was, but since it took place long after the mach transition it wasn't promising to hear. Upon looking at the GPS, I see that I never re-acquired lock after launch - f***. After driving blindly around in circles for a little while, the Hillbillies (I think) called on the FRS radio with reports of a found rocket that met the exact description of mine. So we headed over to their pad to talk with them, at which point “something that looked like my rocket” was in sight. Unfortunately, it turned out to just be the airframe (with a short zipper in it), motor case, and some harness. Some more time driving around looking for the nosecone and parachutes turned up nothing.

Later that afternoon, I stopped by the LCO desk just to see if any other pieces of my rocket had turned up. And guess what was there? My nosecone! Er, what was left of it anyways. Looking at the remains, it was quite obvious that it broke free from the rest of the rocket and came in ballistic. The whole thing was busted up pretty badly, as you can see...

IMG_2701.jpg

The Stratologger was unscathed and the RRC2+ had components broken off. But after replacing the broken 9V batteries, both altimeters powered up fine, much to my surprise. As luck would have it, Jim Amos from Missileworks was present at BALLS - he's a really great guy and it was nice to shake his hand! Jim listened to my dilemma, added my altimeter to his pile of stuff he was bringing back to Colorado, and fixed it up for me. Not long after that event, he sent me a summary of the repairs and mailed the altimeter back to me, good as new. Thanks again Jim!!

My BRB900 and Tender Descender remain out at Black Rock somewhere.

As for the flight itself. Looking at the recorded data from both altimeters, the early deployment happened well after the mach transition, so it wasn't a mach issue. (As I had originally thought.)
Everything beeped correctly on the pad...
The nosecone had 3 x 4-40 nylon screws, so it didn't drag separate...

Hmm. I guess this one shall remain a mystery for the ages! What continues to baffle me is the fact that both altimeters recorded a peak altitude of only about 5K-6K, nowhere near what I was expecting. So here we have a bit of work gone in a few short seconds and an M1550 Redline down the drain. BUT, I'm not too disappointed as this seemed rather insignificant compared to my next crash...

So, onwards and upwards!

Great BALLS of Fire 2.0

I'm actually looking forward to this rebuild as it will allow me to make some design changes that I needed to do anyways. Here's the "punch list" so far:

  • Redesign deployment scheme.
  • Replace nosecone.
  • New harnesses, chutes, etc.
  • Re-attach rail buttons somehow. My previous method wasn't strong enough.
The other line item I had to add today was "repair fin can." Upon further examination (a fancy way of saying I hadn't looked at this rocket in months), I noticed that one of the aluminum fins had gotten bent out of position upon landing on the playa. Damn. Fortunately though, after getting in touch with Mike Fisher he said that is IS repairable. I could probably even do it myself, but Mike was willing to put it back on his metal forming equipment to get everything back into position. (Much better than whatever results I could try come up with using hand tools.)

UPS delivered my order from Proline Rocketry yesterday:

IMG_2846.jpg

Here we have a new nosecone and a set of av-bay bulkheads. I know some of you out there (Manny) were a bit concerned with my previous nosecone selection, so I went for a filament-wound 5:1 Von Karman with coupler this time. Seems much better suited for my application. Gary T. is a fabulous guy to do business with, easily one of the best dealers to order Performance Rocketry composite parts from these days. He's quick to return phone calls/emails, and ships fast. Thanks Gary!

As for deployment, I never was entirely pleased with the reliability of my previous method, and it never worked properly anyways. This time I'm going to use a trick I learned from my buddy Steve Heller (aka prophecy). Rather than glue the nosecone coupler in, use it as a standard av-bay with shear pins on both sides. Drogue chute inside the airframe, main chute inside the nosecone itself. (I may end up reversing these depending on space.) The whole design will be much cleaner and simpler than the Tender Descender/line cutter idea. And thanks Steve for the suggestion!

For altimeters, I'll probably swap out the Stratologger for a Raven2, just because. (Keeping the RRC2+ as a backup.)

More to come as progress is made!
 
Here we have my av-bay components. Thankfully the bulkheads came with the center hole pre-drilled, which made for much easier alignment and drilling of the outside holes. Drilling them by hand wasn't too bad except I broke a 1/4" drill bit in the process. :facepalm: It was dull as hell anyways...
IMG_2849.jpg

Av-bay bulkheads with forged eyebolts installed.
IMG_2855.jpg

Assembled components.
IMG_2857.jpg

Fitting everything together!
IMG_2851.jpg

Altimeter selections - a Raven2 and the newly-repaired RRC2+.
IMG_2852.jpg

Mounting them on my sled. Another advantage with these small altimeters is that I can use a smaller sled, fits better in the av-bay, etc.
IMG_2854.jpg

That is all for now!
 
Back from hiatus!

IMG_2877.jpg
Internal av-bay wiring mostly complete, including with Featherweight screw switches and a terminal block to aid with Raven connections. (Note: as of this moment I am only using channels 1 and 2.)

IMG_2879.jpg
9V batteries secured to the back of the sled.
 
With the exception of drilling a few more holes for vents and shear pins, my new and improved av-bay is complete!

IMG_2881.jpg
Wiring all finished, with crimp-on connectors installed. (My standard.)

IMG_2882.jpg
Assembled bay. The little "eyeballs" are access points to my screw switches.

IMG_2884.jpg
Drogue/bottom end of the bay. Here I will attach surgical tubing-style charges, since I expect to get 30K+ out of this rocket. In case you're wondering by now: P = Primary (Raven2), and B = Backup (RRC2+). You can never have too much labeling...

IMG_2885.jpg
Main/top end of the bay. This side houses standard PVC cap charge holders.

I tested and double-checked all my circuitry today and it worked perfectly, altimeters beeping the way they should be and all that good stuff. I'm tempted to go drogueless on this rocket like I usually do, but am concerned about stripping the main (like what happened on its maiden flight). Hence I'll probably add a 15" or 24" drogue, but I still need to calculate a main chute size.
 
Why didn't you do surgical tubing on both sides of the av bay? Or pvc caps on both sides?
 
Why didn't you do surgical tubing on both sides of the av bay? Or pvc caps on both sides?
When using black powder at high altitudes, it generally works best when sealed away from oxygen since the pressure at that altitude can be a problem. Surgical tubing helps this process. And personally, I find PVC caps easier to use so I like to implement them whenever I can.
 
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