PML's Quantum Tube.......

I just posted a message on another thread that had to do with PML's quantum tube, and I just got to wondering what everyone here thinks about it.

Now, I love the stuff. I have 3 PML kits that are built from it, and I have scratch built 5 or so other rockets with it. After talking to many other rocketeers, my opinion is that I may be all alone in my admiration of this stuff. Many people, and MOST "old-timers" hate it. Not just hate it, They despise it.

Here are the reasons I like it.

1) No Glassing.
The stuff is STRONG. Ask someone who has been around a while in rockets why they glass an airframe. Most of the time, you do not need the strength of the glass for the flight, but you want the glass to protect the rocket when it is NOT flying. I have had more cosmetic damage to rockets while transporting them, then I have ever had in-flight. I find QT holds up as good as glassed rockets in this regard.

2) No Spirals to fill.
Gotta love that! Perhaps the worst job in rocketry is avoided with QT!

3) Easy to finish, and easy to get nice results.
I paint my rockets for utility. I don't need an automotive paint job on a rocket, because I know what it is going to look after 3 or 4 flights anyway. I also have terrible painting practices... I don't wait long enough between coats, I Mask too soon, I remove masks too soon, Etc. I painted my PML BBX (5 colors and an semi-elaborate masking pattern) in 8 hours, Start to finish... Way too fast! But, It still looked GREAT! Gotta be the QT. (See a pic of this rocket by going to the PML web store, Scale kits, and scroll down to the Black Brant x.)

4) Holds up well during flight.
I have many instances of QT rockets that have ejected early or late, with no damage to the QT. Almost all of my non-QT motor ejection based rockets have some slight damage up near the nose cone where early or late ejections have tried to zipper. I have also seen many QT/G-10 rockets fall from very high, with either stripped or undeployed chutes that have resulted in no damage other than surface scratches.. One AMRAAM I saw fell from 2000 feet, bounced 3 feet in the air and sustained NO DAMAGE. I'm sure a phenolic rocket would have been toast.
In the interest of being fair, I have had two mishaps that have caused damage to QT rockets: 1) blowby of an AT I-161 that resulted in a seriously melted tube and 2) zipper caused by a WAY too early ejection of an AT I-285. Both were easy to repair by removing the damaged piece of QT, and installing another.

Ok, that's why I like it. Here are some reasons that are given as to why it should be avoided:

1) Too Heavy...
True, it is heavy. I say: Bigger motors....

2) Shrinks / expands with heat and cold
YES!. This is a problem, and it mostly manifests itself with the piston assembly. TIP: Do this if you plan on flying your PML QT rocket with a piston in cooler climates. Before building your rocket, place your QT in a chest freezer and begin sanding your piston. After sanding for several minuets, take the cold QT from the freezer and drop the piston in it. If it does NOT fall all the way to the bottom without assistance, put the tube back in the freezer and continue sanding until it does. Do not worry about making the piston to loose. You CAN NOT make the piston fit too loose.

3) Epoxy will not easily bond to Quantum Tube.
When scuffed (80 /100 grit paper) in the areas to be bonded, I find the bond to be more than adequate.

So, what do you guys think about it? I like it, darn it!

Todd Moore
TRA#8650 L2

Todd,

Nice report and good topic; I have been wanting to talk about this for a while now myself and now is a good time.

My vote was a BIG YES, as far as liking this stuff. The piston system used to bind in some of the Phenolic kits that PMl sold, but the Quantum tube, with it's smooth polymer "shotgun" style bore has eliminated that problem. Also as was mentioned, the stuff is flexible, which equates to sturdy, a DREAM to paint, easy to glue and a godsend to clean as you can wash it under the sink or with a hose! Try that with paper or phenolic! As far as weight goes, a 36" piece of 3.9" tube is only a couple ounces more than a phenolic tube...no big deal to me.

If you have to glass the stuff, only do the fin areas because, as was mentioned, it does shrink in cold, which turns out to be a catch 22. If it's cold you want to glass anyway. In temps below 40 degrees, Quantum does shrink noticably and becomes as brittle as phenolic in temps below 32 degrees. Glassing the fin/landing contact area turned my Quantum into steel, so now I fly without worry during our cold Mid-Ohio launches. However, since most of my launches are above those temps it works for me and works well.

Will I ever use Phenolic, only if it's glassed; paper, sure and you can glass it too; Quantum, ALL THE TIME!!! I love this stuff and have continued to design and build my armory of missles around it since I think Quantum is the next best thing since sliced bread!

Carl

Todd

Well you are not as alone as you think. I like working with the stuff. You nailed most of the reasons as well. No, I won't be building and MD Mach busters with it, however for routine work I really like QT.

A

QT is great stuff! I have a few PML kits that use it, and it's been great to me so far. I don't really push limits with my flights, so it's fabulous!

Add another big yea to the list. It may be heavy ; but sure is durable. I've see QT rockets fall 1000+ feet and come away with no damage. Gotta love that.

Now if it would just slip thru the rocket eating trees.

Al

Will have to check it out..Am thinking very seriously of doing my L1 cert with a Phobos...

Pantherjon said:

Will have to check it out..Am thinking very seriously of doing my L1 cert with a Phobos...

Click to expand...

The Small Endeavour is a great kit for L1. Flies great on G and H loads! I think every fleet needs the PML Amraam 2.1...awesome rocket!!!

I like the QT also. I have an IO and a Pit Bull. Both fly very nice. I got my level 1 cert on the IO with an H123. Landed less that 100 yards from launch pad. The Pit Bull flies great. I did have a mishap with it. The chute was balled up and it fell from about 3000 feet. Do you think it could miss the paved road?
Of course not. What a horrible sound a rocket makes when it bounces. Only damage was a fin almost knocked of and a scratch on the nose cone. I will probably build more PML rockets. Now I am hoping to get a nice level 2 rocket for Christmas. Happy Holidays to everyone......

JimmyL said:

...... What a horrible sound a rocket makes when it bounces.......

Click to expand...

Would that be the wierd sound like a sick wind chime?:flute:

Yea, that is a good way to describe it. Add a little scrunching sound and you are right on it... Sad part is I could have easilly caught it and avoided the damage...."Never allowed to catch a rocket" One of the questions on the level 2 test....I guess the better plan is to be more careful when packing the chute.....HO HO HO!! Merry Christmas to all...

Loopy said:

The Small Endeavour is a great kit for L1. Flies great on G and H loads! I think every fleet needs the PML Amraam 2.1...awesome rocket!!!

Click to expand...

Yeah thats a sharp lookin rocket...I think I would go with the Amraam 3 tho!

Todd I to have built a fair amount of PML kits with it. One of which was a 4" Endeavor. I flew it on several K motors over its time. Including some beefy ones that it flew to over 11 and 12K on. Never had an issue. Of course im not a big piston guy. Always have done the burrito wrap method with lots of success. All of its flights were also dual deploy and I also found the quantum cleaned easy from the bp scum. So I like It. BUT if I have my choices I would rather do convolute glass or filament wound glass. They are even stronger and lighter clean up easy are durable and have none of the issue that the quantum tube does. Would I still fly a Quantum tube rocket. Sure.

Pantherjon said:

Will have to check it out..Am thinking very seriously of doing my L1 cert with a Phobos...

Click to expand...

Actually I did mine on a Phobos. About 2100 feet on an H128. Worked fine and still flying 8 years later. The H165 works well too.

Al

Most of what I've heard is you never layup glass or cf over Quantum. So the recommendation is never take it to mach 1 or higher. Of course I'm a long ways from getting to ever push it that hard. But since I'm in the building process I'm trying to build in whatever I can to make the most of what I have. I'm going to cf the G10 fins at least.

Michael

mrmonteith said:

I'm going to cf the G10 fins at least.

Michael

Click to expand...

Why? If you're not approaching mach, there's no reason to re-inforce fiberglass fins. You'll just add weight and expense. The best thing to do if you want to make the kit stronger is to fiberglass the fins to the motor tube. The motor tube will take epoxy very will, and this step will make your fin attachments rock solid without adding a whole lot of weight.

You are correct in that you don't do layups over Quantum tubing. The tubing doesn't allow epoxy to penetrate, so the layups won't stick to it.

mrmonteith said:

Most of what I've heard is you never layup glass or cf over Quantum.

Click to expand...

Which is a point that floats around. It's interesting because in the two 2 stage kits that PML sells in QT, they include FG to reinforce the fins.

I believe what is meant in the QT/FG discussion is that doing a laminated tube based on QT is probably pointless. The adhesion is not ideal as the resin does not soak in.

I second Loopy's question on why do a CF layup on fins for a QT based rocket. You will not likely see the kind of performance where the CF comes into play.

That is unless you like my kind of performance where the parachute is optional and I need to build the darn things to bounce when they hit the ground.

A

I have nearly always glassed my lower fins on Quantum tube and for good reason. We fly in very cold weather here and a plowed field turns into concrete chunks in the cold. I actually failed my first attempt for a Level 1 cert, due to the weather and not the rocket. It was a perfect launch, flight, deployment and gentle decent, however, when the non glassed lower fins hit the ground, one flexed enough to crack away a 1/4 width chunk of Quantum tube from between the fins due to flexing. It looked like a great landing as I approached, but the broken side was facing down and was the side that hit.

I took it home, glassed the fins, showed up the next day with a model that had the lower fins and tube still in primer and this time got my cert. I only glass lower fins to prevent these such beatings that they take in the cold winter and it has always paid off. As far as Quantum and glass not sticking, I have had over 40 J flights on my PML AMRAAM 4 and the model still looks new. The rest of the fleet falls in line with this line of thought.

So yes, if prepared properly, fiberglass cloth sticks just fine to Quantum. I use 60 grit to cut some serious grooves in the tubing and have never had any problems. I guess it all comes down to what kind of weather you wish to fly in and in my case, it sure doesn't hurt.

OK, I'll be the one dissenting opinion. I don't care for it.

I have a PML Ariel with QT. On the first flight, the rocket (with stock chute) landed in grass, cracking the tube (about (0.5") at the top and bottom of one fin root. I fixed the cracks with epoxy. On the next flight, the exact same thing happened to a second fin. The fins and epoxy joint were fine. The QT failed. I put a hose clamp around the aft end of the tube, and that seemed to strengthen the fin area on subsequent landings.

I'm on the fence on this one; I don't completely hate it , but it's not my favorite.
I'll use it for a quick payload section/ Alt bay setup.
Not for a booster/ fin can setup though, I'd rather use phenolic instead.




JD

Proven 'Soccer Hooligan' resistant,

gotta love that stuff....

But, the REAL test would be European 'Soccer Hooligans'!

I'm not too sure the Cheyenne mtn complex
can handle a full blown invasion by European
Soccer Hooligans...

Let's get back on subject guys and not hijack the thread.

Carl

CTulanko said:

Let's get back on subject guys and not hijack the thread.Carl

Click to expand...

As a reformed English football hooligan (just thought I'd slide the thread nicely back to QT vs Phenolic )

I ticked " spawn of " in the poll as I have had a couple of bad experiences with QT. When it first came out I suffered from the non-stick aspect and had a 4" H powered 3FNC come down with a tangled chute. The after landing damage was confined to the fins but all had come loose from the QT, despite fillets. We all learnt from the early days and when I built a 4" upscale Mosquito I made sure all the surafaces were seriously abused before gluing (30 min epoxy of proven ability). It suffered a deployment charge failure from about 300ft on a G64 RMS into soft, ploughed earth. The after impact damage was extensive (the fins all survived :surprised: ) but the QT had shattered around the nose cone. The motor mount and fins were still attached to each other but had been split from the QT body tube (sorry no pics ).

My worry is the internal fixing of CRs etc. where it isn't as easy to get a good surface in the right spot and I am reluctant to trust QT with high power as a consequence. There are plenty of ways to overcome this but the whole point of QT is simplicity of construction yes-no?

My Callisto hit a paved parking lot and survived, makes a great finish and the fins are VERY strong.

Here's some evidence that a long section of it can handle some stress.
Everything between the fin can and the reducer is Quantum. I crammed it straight up on an Ellis H275, a bunch of acceleration. OK, only about 13 Gs, but there's a lot of length there for wobble to build up, and it didn't. It's also read ejection, so the nose hits the ground, and it boings right back up due (I assume) to the Quantum's springiness.

https://www.rocketreviews.com/reviews/mods/at_recycled_mirage.html

Quantum Springiness?

Isn't that something they were going to try and prove at the Supercollider before the project got canceled?

I've built at least 10 QT rockets and flown them on motors up through K's. I have never had a fin joint fail. In fact I have had a G-10 fin actually tear/break on a hard landing but the glue joint held, the break was about 1/4" away from the body tube. I still prefer glassed phenolic for high performance rockets, but for ease of construction on sport rockets you can't beat QT. After what some of my rockets have been through I can't see how anyone can blame the QT if a glue joint fails.

I've used it for a lot of sport rockets and love the stuff. Personally I'd probably have liked to have traded a little extra weight for a bit more strength and upped the wall thickness 25% or so to make it even more ding-resistant, especially on the 3" and 4" stuff... but in general it's lovely to work with, and very quick to finish.

I don't use phenolic any more if I can possibly help it.

QT for small sport rockets, glass/carbon or aluminium for everything else.


my 2p

Ben

Just a little extra thing to add...


As with most materials... most people's bad experiences have been due (in a lot of cases) to use of the wrong material, or using it in the wrong way, I know I have done that and then been put off other materials in the past.

So long as you use it for what it's designed for, that is, relatively low performance sport HPR rockets, then it is the best material... yes, it breaks in heavy impacts, but so will most common airframe materials, and the advantage is the damage is localised in QT and far less likely to have adversely affected the rest of the airframe, unlike composites which can have stress damage to airframe parts which superficially appear to have survived unscathed.

The glue adhesion issue can be a problem, but personally, having worked with plastics and adhesives for a while I wouldn't want to surface mount or tab-mount fins through any plastic, I've only ever used it with ttw fins that go to the motor mount, and have never had any probs.

imho

Ben