Mach 2 with blue tube

codysmith said:

I can't remember...does OR automatically calculate stability at supersonic levels? I know that the CG shifts during supersonic flights but I don't know how much. I suppose that's not a very good margin in either case.

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Yes it does. Check Tools -> Component Analysis and drag the Mach number slider.

SinfulDarkLord said:

It used to be on the website of ARR, but it looks like they removed it. Basically it was a 38mm rocket on an EX motor. The rocket was very long. It lost a fin in flight and they claim that their tube did not shred. Reached a speed over Mach 3. The tube on the pictures looked like it was on the brink of falling apart.

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If you'd like to know the truth, just ask. ARR spun my flight report to their advantage. It did not survive. It came apart like a de-boned fish and the only part of the rocket I used it for was the fin can. I won't ever use it again. I did some research on fishpaper tubing after that. It is excellent for abrasion and electrical insulation but is not designed for structural loads. At the time, I was working with my tubing manufacturer to offer our own version of fishpaper tubing. After that flight I cancelled the order.

It has it's place, but the way it was being advertised at the time was very misleading, especially when my in flight failure was spun to promote the use of the material.

Binder Design said:

If you'd like to know the truth, just ask. ARR spun my flight report to their advantage. It did not survive. It came apart like a de-boned fish and the only part of the rocket I used it for was the fin can. I won't ever use it again. I did some research on fishpaper tubing after that. It is excellent for abrasion and electrical insulation but is not designed for structural loads. At the time, I was working with my tubing manufacturer to offer our own version of fishpaper tubing. After that flight I cancelled the order.

It has it's place, but the way it was being advertised at the time was very misleading, especially when my in flight failure was spun to promote the use of the material.

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After losing a fin I am pretty sure it did not survive one bit. I knew it was already a bust after that (no offense). I heeded no attention to the loss of the fin. My eyes were only focused on those nasty wrinkles that I am certain are creases on the tube, which is no doubt from the extreme heat and loads. I should have not used the word proven, more like tested and somewhat survived. I am very disappointed in ARR for misleading their product like that.

This was the picture posted on the site, hope you don't mind.


If anything, up to Mach 2 is fine, but Mach 3 is a big no.

Blue Tube is pretty darn tough but adhering to it is a challenge. Through the wall is fine, but surface mount is iffy. I don't know if dado slots would help or hurt.

CarVac said:

Blue Tube is pretty darn tough but adhering to it is a challenge. Through the wall is fine, but surface mount is iffy. I don't know if dado slots would help or hurt.

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how exactly do you make them? I know what they are but have no idea how I would do it.

I don't think dado slots are a good idea. The dado cut basically initiates the peeling mechanism that you are trying to guard against. Don't get me wrong, I feel Blue Tube has a place. It is durable and can take some hard landings, but it has to be used in the rocket design properly. I have projects planned that are TTW using Blue Tube, but they are not "extreme"--the later is why they make CF. We are blessed with a wide range of materials for use in our hobby, but they have to be used properly/wisely.

CarVac said:

Through the wall is fine, but surface mount is iffy. I don't know if dado slots would help or hurt.

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On my BT minimum diameters I cut slots all the way through and use fin tabs the thickness of the tube, then JB Weld the fins on, add large fillets, and tip-to-tip fiberglass. These fin cans have survived some pretty major crashes.

I'm currently building a 3" MD using Magnaframe from Giant Leap, which seems like it has somewhat better material properties.

SinfulDarkLord said:

This was the picture posted on the site, hope you don't mind.
View attachment 180549

If anything, up to Mach 2 is fine, but Mach 3 is a big no.

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No I don't mind. Note how the photos are cropped to not show the leading edge of the tubing. It delaminated there.

Thanks for you insight Mike. That is very good to know. I have used it in the past but have noticed a slight warp in the airframe. It was never exposed to water so I guess it was heat??


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In the future when I use Blue Tube I will either make it easily replaceable or else have the whole rocket easily replaceable.

grouch said:

Thanks for you insight Mike. That is very good to know. I have used it in the past but have noticed a slight warp in the airframe. It was never exposed to water so I guess it was heat??


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The warping is caused by humidity. Hence why they request a sanding sealer like polyurethane minwax.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

Binder Design said:

No I don't mind. Note how the photos are cropped to not show the leading edge of the tubing. It delaminated there.

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I was curious about that. I was like why not show the whole thing? What bothered me the most is the wrinkles at the aft end. It almost looks like it was about to be crush from severe loads. No doubt it was about to.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

CarVac said:

In the future when I use Blue Tube I will either make it easily replaceable or else have the whole rocket easily replaceable.

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You sir are making a wise choice.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

mikec said:

On my BT minimum diameters I cut slots all the way through and use fin tabs the thickness of the tube, then JB Weld the fins on, add large fillets, and tip-to-tip fiberglass. These fin cans have survived some pretty major crashes.

I'm currently building a 3" MD using Magnaframe from Giant Leap, which seems like it has somewhat better material properties.

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The magnaframes are a combo of both phenolic and vulcanized fiber. This gives you the best of both worlds.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

conman13 said:

ok thanks everyone. im going to go with it and see what happens

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So, this thread is a poll asking if Blue Tube will go to mach 2. 40% of the replies say no. And your sill going to give it a try? Your fellow rocketeers are only giving you a 60% chance of it working. Throw in the fact it might be your first min dia rocket, first time at going mach 2.......

Tony

CarVac said:

Blue Tube is pretty darn tough but adhering to it is a challenge. Through the wall is fine, but surface mount is iffy. I don't know if dado slots would help or hurt.

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Like most glues the bond is sometimes stronger than the material. Plain old epoxy held up just fine even after the BlueTube came apart. In 12' of fin attachment there wasn't a section where the bond failed

Blue tube I feel is a more than adequate material for sport flying. For high performance, simply no.

This rocket in the photos was a 4" BT airframe with plywood fins glassed tip to tip with 6 oz. glass. It housed a 75mm mount and was a zipperless design fin can with a single piece of upper airframe. The av bay slides up the tube and is secured with screws so as to limit the airframe breaks. The first photo snagged from Rockets Mag sample photo page from Balls 19 is one of the last good pictures of my rocket. You may recognize it from ARR's customer website where the motor is mistakenly listed as an L2200. It was a L2600 actually. Full L, stepped cores, ~2 sec burn. Absolute hammerhead! Loved static testing and flying it.



This is a photo my buddy Bob snapped of my table after I spent an hour picking up all the pieces from the playa. The large white section was the part that the av bay slid up into so it was double walled. The rest as you can see is not much larger than 2". All the fins stayed on through the burn. Best guess is they came off when it went unstable. Got them back mostly undamaged. Examining Rockets Mag photos Neil got a great one of it boosting up through it's own debris cloud! My thoughts on what happened was the airframe or coupler buckled and that was the beginning of the end. According to sims it was supposed to get somewhere around Mach 1.8 and I don't even think it got there so not even Mach 2 and it failed.

So, I used it for a minimum diameter 54mm rocket back in like 2010 and it went about mach 2 and quarter. No problems whatsoever.
https://www.youtube.com/watch?v=YJNV3Kj3xqA

This last weekend I took it to about mach 1.7 with a 38mm min dia with no tip-tip.
https://www.youtube.com/watch?v=Jc4eyQR9GfM
hard landing, and yet again no problems.

However Ive seen it fail below mach under high stress as well. My friend took this video, ignore his commentary. The actual problem (or so I was told) was that the BT coupler failed.
https://www.youtube.com/watch?v=b6p8eMwyTNA&index=74&list=UUZHQd8FdnPL3VB6hVSZ6MFw

These are the facts.
I reccomend bluetube for motor mounts, light couplers, avbays and nosecone shoulders, not airframes subjected to mach 2.5+ . But as shown atleast with my rockets and many more, it CAN handle it.

There are a lot of factors. https://www.rocketmaterials.org/datastore/tubes/Axial/ has some real tests on BT and other materials. On the basis of this and my flight experience, I've decided to use Magnaframe instead of BT on my 75mm MD, and we'll see how that goes, hopefully at BALLS.

Here's what my BT 54mm MD looked like after a K1440 flight. I can't say for sure that the root cause was a tube failure, but certainly the tube didn't fare all that well and I can prove that the fins didn't come off.

tfish said:

So, this thread is a poll asking if Blue Tube will go to mach 2. 40% of the replies say no. And your sill going to give it a try? Your fellow rocketeers are only giving you a 60% chance of it working. Throw in the fact it might be your first min dia rocket, first time at going mach 2.......

Tony

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Your right I think I may end up making a Carbon/Kevlar tube and using it instead. It seems like it is close to 50/50 but I want to end up on the winning side


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