24mm reload case

[Lucky 94]

In future rockets I am going to leave room for improvement, but right now I am just getting into RMS and higher power rockets,( and the head aches that come with them ).

 

[loopy]

Lucky - I'm much the same way. I lose very few rockets because I try not to push boundaries too hard...lol

You'll love the 24mm loads in the RMS casing. And like I said before - once you've assembled a couple of them, you're used to it and can almost do it in your sleep. That being said - you still need to pay attention to all steps while assembling a load. Many catos are caused by user error, and the easiest way to prevent that is by having as few distractions as possible while assembling. If someone stops to talk while you're building your motor, stop assemby and talk. When done, resume building.

 

[rmpitzer]

Originally posted by Lucky 94
Any tips for this.

My only tip is to use the copperhead igniter. I've seen quite a few of these cases blow the rear closure, and in all cases, they used some other form of igniter. My theory is, the larger igniter plugged the nozzle, the motor over pressurized, and popped the rear closure.

I have dozens of flights on my 24mm case, and never popped a closure, and I've only used copperheads in them.

-Rich

 

[loopy]

Originally posted by Rich Pitzeruse
My only tip is to use the copperhead igniter. I've seen quite a few of these cases blow the rear closure, and in all cases, they used some other form of igniter. My theory is, the larger igniter plugged the nozzle, the motor over pressurized, and popped the rear closure.

I have dozens of flights on my 24mm case, and never popped a closure, and I've only used copperheads in them.

-Rich

Ditto.

 

[Lucky 94]

i have heard bad reviews for the copperheads, but i can't afford anything else at the moment.
Is there anything but friction fitting for a min diameter rocket?

 

[richalex2010]

If it were 29mm+ there's Slimlines and Aeropack retainers (not perfect but no tape for RMS). I haven't seen them in person, but it appears that Rowes Retainers makes 24mm retainers that might work.

Can't think of anything else off the top of my head

-Jake

 

[Lucky 94]

i will have to try them. How much and can you point me in their direction?

 

[doug_man_sams]

Originally posted by Lucky 94
i have heard bad reviews for the copperheads, but i can't afford anything else at the moment.

Take a cigarette lighter and fire up the non-pyro end. The foil will delaminate, and it's then much easier to get good connections to it. No tape or special clip is then required. I've had good - but not perfect - results this way. Once in a while, one won't light, but that's the case for just about any ignitor.

Is there anything but friction fitting for a min diameter rocket?

I've used external hooks. They can be faired in very nicely with the usual filling materials - epoxy, FNF, bondo, etc - but you're probably well past that now.

So, in addition to friction fitting the motor, you can add another wrap of tape around the end of the rocket straddling the seam between the bodytube and motor thrust ring. That should be more than adequate. IOW, if it comes off, you had so much ejection charge, you were gonna blow up the rocket anyway

Seriously, the beauty of using two simultaneous retention methods is that they tend to back each other up. For example, if the ejection pressure is enough to tear the outside tape, this pushing against the tape will dissipate most of the forces. There then won't be enough momentum left to overcome the friction fit. The motor might move an eighth or quarter of an inch, but the friction wrap will still hold it well.

So relax. It will work just fine.

Doug

 

[Lucky 94]

So just tape the motor to the rocket. Will try.

 

[rmpitzer]

Originally posted by doug_man_sams
Take a cigarette lighter and fire up the non-pyro end. The foil will delaminate, and it's then much easier to get good connections to it. No tape or special clip is then required. I've had good - but not perfect - results this way. Once in a while, one won't light, but that's the case for just about any ignitor.

I agree, this is exactly what I do. And like Doug says....yeah, sometimes a copperhead fails, but usually they work ok. Just make sure there are no copper threads on the sides of the igniter (which could cause a short to the other side) and usually they work ok. I'd rather replace a faulty igniter, than replace the case.

-Rich

 

[loopy]

Originally posted by Rich Pitzeruse
I agree, this is exactly what I do. And like Doug says....yeah, sometimes a copperhead fails, but usually they work ok. Just make sure there are no copper threads on the sides of the igniter (which could cause a short to the other side) and usually they work ok. I'd rather replace a faulty igniter, than replace the case.

-Rich

Exactly. I don't separate the pieces on mine, and I still have pretty good success with them. Just make sure the edges are clean, then put two wraps of masking tape on one side of each clip on your lead. Clip them with the tape on opposite sides of the igniter, and you're good to go.

 

[Rick Lindsey]

Originally posted by Lucky 94
i have heard bad reviews for the copperheads, but i can't afford anything else at the moment.
Is there anything but friction fitting for a min diameter rocket?

Testing with an ohmeter will weed out most of the bad copperheads. We had nearly 100% fires with copperheads once we started checking the resistance of each one. If it's less than bout 0.9 ohms then it's not going to work (I may have had some at 0.8 ohms that worked), and it shouldn't be more than about 1.5 ohms. Take a grain of salt, though, as I'm remebering those numbers from a decade ago -- it's easy to work it out for yourself though once you start monitorign the resistance of the copperheads and see which ones work and which ones don't .

-Rick

 

[Lucky 94]

Yep, this case cost me almost half of all the money I have been saving for 2 years.

 

[m85476585]

Originally posted by Lucky 94
i will have to try them. How much and can you point me in their direction?

Aluminum motor retainers (Aeropack, Slimline, PML HAMR) are the MOST expensive way to retain motors. For example, a 29mm Aeropack is $28 from Commonwealth. The ring can be used with many bases, but the base is glued to your rocket, which means you have to spend $16 per rocket after you buy a set for $28. I'm guessing you will decide to go with a cheaper option.

For minimum diameter you can try to make some kind of external hook or bolt that is streamlined enough not to create too much drag (streamline it with epoxy or a filler)

Also, friction-fitting is enough as long as you make it very tight, but a backup is good.

 

[Lucky 94]

I will have to use friction fit for now.

 

[Rick Lindsey]

Originally posted by Lucky 94
I will have to use friction fit for now.

Friction fitting worked fine for me for years.

-Rick

 

[Lucky 94]

Plus I am not going to be able to do anything more then 29mm for a few years.

 

[paulk]

Originally posted by Rick Lindsey
Testing with an ohmeter will weed out most of the bad copperheads. We had nearly 100% fires with copperheads once we started checking the resistance of each one. If it's less than bout 0.9 ohms then it's not going to work (I may have had some at 0.8 ohms that worked), and it shouldn't be more than about 1.5 ohms. Take a grain of salt, though, as I'm remebering those numbers from a decade ago -- it's easy to work it out for yourself though once you start monitorign the resistance of the copperheads and see which ones work and which ones don't .
-Rick

Thanks for the tip Rick. I seem to have about 50% success with copperheads, and the typical failure is simply that the copper foil is shorted somewhere. Funny thing is that the igniters that come with the reloads regularly fail to work for me, but the ones I bought in a separate pack almost always work. Maybe just a coincidence. What resistance do you see for a shorted igniter? FWIW, I always use a interlock clip.

 

[paulk]

Originally posted by Rick Lindsey
Friction fitting worked fine for me for years.
-Rick

Ditto. I use exclusively friction fitting with an outer wrap of tape on my 24 rms, and it hasn't failed me yet.

 

[Rick Lindsey]

Originally posted by paulk
Thanks for the tip Rick. I seem to have about 50% success with copperheads, and the typical failure is simply that the copper foil is shorted somewhere. Funny thing is that the igniters that come with the reloads regularly fail to work for me, but the ones I bought in a separate pack almost always work. Maybe just a coincidence. What resistance do you see for a shorted igniter? FWIW, I always use a interlock clip.

0.6 ohm is almost always shorted, 0.9 is almost always good, and between 1.0 and 1.5 ohms is typical if I recall correctly. It's been awhile since I ohmed a copperhead . Need to get a new pocket multimeter!

I'm not surprised on the copperhead-in-motor vs copperhead-in-pack. Back when i was flying regularly, the copperheads were just sort of loose in with the motor components, and could get banged up, while the ones in the pack didn't have anything to squash them. I think they may have started shipping them in little carboard tubes to avoid that now though? I'm noot sure how they come these days, as I've been flying mostly estes of late.

-Rick

 

[loopy]

Originally posted by Rick Lindsey
... I think they may have started shipping them in little carboard tubes to avoid that now though?...

Yes, they have.

 

[Lucky 94]

That is good.