New Strength of materials Testing

I don't have any poop pipe to donate!

But I have some motors you can fire in your temperature chamber from

+800 to -200 degrees :)

Jerry

Doc, you rock!

Do you have a PayPal account? Maybe you could setup a "donations" link on your website. If you were able to collect some money, you'd be able to buy whatever products you needed to do standardized testing rather than just going with whatever scraps people send ya or dipping into your own stash. I doubt i'm the only one without "spares" of many supplies, but would be glad to donate the cost of a tube in order to get some hard data.

It's already been proven that rocketeers donate $$ to good causes.

Dan Chandler Southern New England Association of Rocketry

I do have a "Premier" PayPal account with my email address but I never thought about asking for monetary donations. All the testing I have done to date has been using the generous donations of samples I have received.

I'll be doing some of the temperature testing on the Quantum tubing in a PML Bull Puppy kit I won at the 2003 NSL. I don't know if I have the heart to cut it up, so I wont be doing the brittleness tests on it.

Testing starts @ 7:00 AM tomorrow morning.

-- Drake "Doc" Damerau

NEPRA President NAR Section 614 NAR 79986 L3 Remove "My Shorts" to reply

Now Jerry, you know I can't burn motors in my lab. But, I bet I have a NIST traceable load cell with twice the capacity as ANY thrust motor that USR sells!

-- Drake "Doc" Damerau

NEPRA President NAR Section 614 NAR 79986 L3 Remove "My Shorts" to reply

I'm sure you do. So let me bend it :)

Please?

Jerry

I did my own testing on Quantum Tube yesterday. My beloved 4" Der Red Max suffered a lawndart due to the delay grain failing to remain ignited. She came in ballistic from about 1100 feet, pile driving in to the ground. It completely buried the full length of the nose cone, and a shovel was necessary for recovery! I expected that the airframe would have shattered, but this was not the case. The rocket was fine, no cracks in the fillets or airframe. The nosecone was trashed however. I suspect that if I had a longer airframe, (my DRM has 21" of tubing) it would have shattered, or at least cracked. I know some guys don't like QT, but I'm sold on the stuff.

If I had some extra QT, I'd send it to you. Some testing would be very interesting.

-- Joe Michel NAR 82797 L1

Note to Ray Dunakin:

I just replied to your note about HPR safety.

Then read this post. It perfectly illustrates a) how dangerous HPR can be, and b) how there is a trade-off between perceived 'qualty' vs. 'safety'.

Viewing this, it would appear in my mind that the airframe and nose cone SHOULD have shattered, simply as a matter of safety. Yes, did it save the rocketeer from having to rebuild his rocket? It sure did. But what would have been the result if it HADN'T impacted in dirt.

I have no problem with launching a non-frangible rocket in an area where safety is assured (to some degree). I have a bigger problem when the mindset of the community seems to be of the "Tim Taylor" school of rocket building, purely for the sake of it (let me rephrase that -- I have no problem with it per se, I have a big problem when it's at the cost of major safety factors).

David Erbas-White

I hereby officially declare you christened!

Jerry

PML product BTW.

It's not just the diameter that shrinks.

How many 36" pieces do you need? At 10.95 each, we should be able to gather enough donations to buy from PML and ship them directly to you. All we need is where to tell them to ship them.

I'll pitch in for a couple ($25.00).

Bob

p.s. I'll be out of town for the week, but figure it'll take that long for arrangements to be made with PML.

Thanks, Jerry! Yea sh*t happens. I think the flight right before me cursed me. PML AMMRAM 4, lawndart. That one shattered in to a bazillion pieces on phenolic tubing!

-- Joe Michel NAR 82797 L1

It's not the only thing that shrinks :)

Oh, rockets. Sorry.

I don't think anyone assumed that only the diameter shrinks. To illustrate this, I'm measuring a length of 13" tubing I have. I'm starting at 150 (as if it was in the hot sun) down to -40ish.

materialized. I

-- Drake "Doc" Damerau

NEPRA President NAR Section 614 NAR 79986 L3 Remove "My Shorts" to reply

I have a PML BullPuppy here I am going to use for the shrinkage tests.

I would also like to do some brittleness tests at various temperatures with a few pieces. Those pieces, along with the tube crush pieces will be destroyed. (I love destructive testing!)

The tube crush pieces should have a L/D ratio of 2 to 3 for the results to not include column buckling. That means I can get at least 7 tests from one

36" piece of 2.1 airframe.

The brittleness test pieces should be the same length as the OD of the tube. I should be able to get at least 15 test pieces from a 36" piece.

Any Quantum tubing pieces one wishes to send for testing can be sent to:

Drake Damerau C/O Chamberlain Scranton Army Ammunition Plant

156 Cedar Ave Scranton, PA 18505

-- Drake "Doc" Damerau

NEPRA President NAR Section 614 NAR 79986 L3 Remove "My Shorts" to reply

The point is moot! My rocket weighs 5 pounds. What difference would it make if it had shattered or not? It still impacts with the same energy. I took every safety precaution in carefully prepping my rocket, and assembling the motor. Through no fault of my own, the delay grain decided that it did not want to burn.

We fly from an 'N' power capable field, and every possible safety precaution is taken. Shit happens, and that's rocketry for you. You may be killed going to work tomorrow. Your wife might run away with your best friend. There is risk in just getting out of bed in the morning.

-- Joe Michel NAR 82797 L1

We can save on the shipping (8.50) if we all pitch in to the same shipment. Someone needs to work on setting this up with PML. Like I said, I will be on travel 'til Friday.

Also, anything else from their stock that would be worthwhile testing?

Bob

That's the old "pound of feathers vs. pound of lead" question. I'd far rather be hit by something frangible than by something that remains aerodynamically intact and will penetrate farther. You're right, impact energy is the same, but I'd rather that the energy be expended in ripping the rocket to shreds and scattering the pieces than in drilling me into the ground. Do you honestly not understand that concept?

BTW, nobody said it's any fault of your own.

I'm not sure what you mean by 'N' power capable field. If what you are referring to is some arbitrary agency (NAR/TRA etc.) number I'm not sure I'd go along with it. For example, I don't really care how big an engine you have, as long as folks are outside the danger zone if it CATOs, and that the field is big enough for both the projected (or possible) altitude, and winds. If by 'N' power capable field you mean that everything within range of the rockets landing zone (normal or ballistic) has been cleared, I'm with you. I'm even with you if everyone present is AWARE of the possible dangers, etc. But for heaven's sake, you have to sign your life away just to be present (for example) on a paintball field. Are you trying to tell me that similiar dangers don't exist for high power rocketry?

But frankly, if I was a scum-sucking bottom-feeding ambulance-chasing lawyer, and there was an accident where someone was injured by an incoming ballastic, you can guarantee that discussions like "look how deep a hole my rocket dug, isn't that great" would go towards winning my lawsuit...

No kidding. But, if you ignore common sense, that's called ignorance (or in the law, negligence). Again, if you truly have a clear field, are taking reasonable safety precautions, and if the people present are all giving INFORMED consent, I have zero problem with it.

Hope not, it means I tripped and died walking down the hall from my bedroom...

You know something I don't know???

Heck, there's even a risk from staying IN bed in the morning... Bedsores, meteors, etc...

David Erbas-White

Makes a huge difference on impact forces. Hence the frangibility clause.That was actually thought through a long time ago and makes great sense.

NO!

No. Not "every" one.

Your opinion currently has enough obvious defects the rest of the stuff you spew cannot be trusted. Work on that.

Jerry