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  #1  
Old 08-01-2009, 01:02 AM
traveler traveler is offline
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Question How long does a Model Rocket last?

The assumption here is that the Rocket is always launched and recovered successfully, launch after launch. Never a crash or mishap.

With that being said: How long does a Model Rocket last (to be flown again)?

I am thinking of the heat from the engine, especially the ejection charge. Does the inside of the tube eventually deteriorate from the heat? The components? Shockcord? And how about shock and stresses? Do parts crack or lose shape over time?

What would be the maximum number of launches before a Rocket would "break" on the next launch?




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  #2  
Old 08-01-2009, 01:33 AM
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BEC BEC is offline
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I'll be interested to see the more recently experienced answers to this. Projecting the condition of my most-flown model since I became a BAR (a simple Semroc Boid which is currently up to 15 I think) I'd have to say that 100 flights is quite feasible. Doing repairs/maintenance as needed and not crashing should lead to literally hundreds of flights I would think. The trick would be replacing a dying shock cord before it failed, for example, and making sure the fins are secure after any hard landing and fixing as needed.

I suppose it could get to the point of the old joke about George Washington's original hatchet (though the handle's been replaced five times and the head four times) or some such...but that's a bit extreme.
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  #3  
Old 08-01-2009, 02:01 AM
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Royatl Royatl is offline
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Quote:
Originally Posted by traveler
The assumption here is that the Rocket is always launched and recovered successfully, launch after launch. Never a crash or mishap.

With that being said: How long does a Model Rocket last (to be flown again)?

I am thinking of the heat from the engine, especially the ejection charge. Does the inside of the tube eventually deteriorate from the heat? The components? Shockcord? And how about shock and stresses? Do parts crack or lose shape over time?

What would be the maximum number of launches before a Rocket would "break" on the next launch?






Yes, heat damage does occur. Yes, paint and glues age, shrink and crack over time. Paper tubes can get damaged by humidity and mold. Balsa generally holds up pretty well, except where influenced by paint. or weathering. And flight stresses can take a toll.

How long they ultimately last depends on how much TLC you are willing to apply to any particular rocket. The best verifiable record AFAIK goes to Jim Flis's Estes Sprint (at least I remember it being a Sprint), that he kept going for 500 flights, the 499th flight being launched by Gleda Estes and the 500th flight launched by Vern Estes at NARAM 47 in Cinncinatti, after which he gave the rocket to Vern. Jim can best tell you what he had to do to keep it flying for that long.

Vern's original Big Bertha (built in ?? 1962 or 1964??) may have more flights than that and it is still flying, at least as lately as a year ago at NARAM 50.

I have an Estes SPEV that I've kept going for over 200 flights since it was built in the mid 70's (lost exact count a few years ago). It has had severe nose cone and transition dents that were filled, engine mount and a balsa transition replaced after hanging on a power line for a week, fins all re-attached at least once, and one fin eventually replaced. Repainted twice, around the original decals. That's not to mention five or six recovery system replacements.
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  #4  
Old 08-01-2009, 02:04 AM
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garmtn garmtn is offline
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Default How long will a rocket last?

I built a "screaming eagle" a few years ago, and launched maybe 6 times. Not one of my better paint jobs but, still have it. The end of BT that nosecone goes into is starting to get soft. To say it will last a 100 flights is ludicrous! With this one, I'll keep launching till it's dead or gets lost. Otherwise a good rule of thumb is 6-10 times then retire it or sacrificeto the "rocket tree god." Glenn NAR89197
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  #5  
Old 08-01-2009, 02:09 AM
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Mark II Mark II is offline
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Well, each one of mine lasts until I build a new one that I want to fly more. And most of the time I'm building new ones. Flying a rocket many dozens of times without losing it or damaging it beyond repair is no small feat, requiring:
  • excellent components in the kit and decent skills in assembling it
  • luck
  • access to wide open, flat, treeless flying fields
  • a big box of luck
  • having lots of eyes on hand to help you track it every time you launch it
  • luck in spades
  • using only fresh motors that have good, cato-free track records
  • an abundance of fortuitous chance
  • consistently good, low wind conditions and excellent visibility when you fly it
  • consistent good fortune
  • conservative (but not too conservative) motor choices
  • winning the luck lottery
  • always insuring that the recovery system is in good condition and packed correctly
  • a heapin' helpin' o' luck
  • proper storage of the rocket at home and suitable protection of it during transport to and from launches
  • beaucoups de chance
A whole host of things other than the factors you list can bring an end to the flying record of a rocket. Most of them are much more likely to come into play, and much sooner, than the types of things that you talk about. IOW, "stuff" happens. At least they do with my rockets, anyway.

MarkII
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  #6  
Old 08-01-2009, 03:29 AM
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Mark II Mark II is offline
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None of the rockets that I had in my early rocketry period in the mid to late 1960's have survived. The oldest rockets that I have are several Micromaxx and mini engine-powered cardstock saucers and pyramids designed by Art Applewhite that I built in early 2004, shortly after I became a BAR. I also have several Micromaxx-powered Bic Stic rockets that I built from plans that I downloaded from Art's site. I have flown some of the Micromaxx saucers and Qubits as much as a dozen times (I haven't kept an exact count), yet they show very little wear (just some soot around the ejection charge ports). After I built each one of them, I sealed the cardstock with 2-3 coats of clear coat to protect them from humidity, and I keep them on a rack on a desk away from any windows and out of the sun when I am not flying them.

My mini-engine powered cardstock saucers and Qubits are flown with Estes A10-PT plugged engines (when I can still find them) and so they never get exposed to ejection charges at all. All of these rockets fly low and slow, so they are always easily tracked and recovered, and they have no recovery systems that need to be replaced. I haven't flown my Bic Stic rockets as much, but they are made of materials that will not break down from exposure to the ejection charges of Micromaxx engines.

Unless I lose them or leave them out in the rain, none of these rockets are ever likely to wear out from being flown. The cardstock Micromaxx and 13mm saucers and Qubits and the Bic Stic rockets can probably survive as many as a thousand flights or more. I also have several larger Art Applewhite rockets (up to a 38mm Cinco) that fly on plugged black powder or composite propellant motors, and these can theoretically be flown indefinitely, too. Because of their size, though, the largest ones naturally land a smidgen harder than the micros, but the only time that any of them would be damaged would be if they landed in the lake.

I also have a number of Micromaxx rockets built from kits by FlisKits and ASP. Because they are so small and fly so high, I usually only launch them if I have exceptional visibility or when I can have help with tracking them, so I don't launch them as often. They are not quite as indestructible as the cardstock rockets, but they are close. Micromaxx motors put very little stress in most of the rockets that are built for them, so these kit rockets can potentially survive many hundreds of launches.

MarkII
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  #7  
Old 08-01-2009, 06:21 AM
jflis jflis is offline
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Quote:
Originally Posted by Royatl
How long they ultimately last depends on how much TLC you are willing to apply to any particular rocket. The best verifiable record AFAIK goes to Jim Flis's Estes Sprint (at least I remember it being a Sprint), that he kept going for 500 flights, the 499th flight being launched by Gleda Estes and the 500th flight launched by Vern Estes at NARAM 47 in Cinncinatti, after which he gave the rocket to Vern. Jim can best tell you what he had to do to keep it flying for that long.



That was a fun one, actually You can see the photo album of that model and its 500th flight here: http://fliskits.com/photo_album/2005/naram47/index3.htm

I built it in 1973 and got those 500 flights over 32 years. The fins, body, engine mount, nose, paint and decals were all stock (original). The streamer and shock cord got replaced a few times over the years and I think the launch lugs got replaced once.

The body tube suffered the most (of the original parts) and there were a few times I had to seal up the spiral with some CA. Other than that it really heal up quite well...
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  #8  
Old 08-01-2009, 09:39 AM
tfischer tfischer is offline
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I have about 6-7 rockets from my original kid-stint as a rocketeer (mostly early 80's, with a few around 1990 when I was in college and a few of us made/flew some one May term). All of them held up perfectly except for the shock cords, which are now repaired, and all are in flyable condition today, save for one I flew last launch and had a mishap (but it will fly again after repairs).

The only other issue I had was the parachute shroud "discs" didn't hold up on many of them. So I just cut little pieces of black electrical tape and all was well again...

Now as to how many flights you can get out of a single rocket, that's another question. But time-wise, they should last a LONG time...

-Tim
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  #9  
Old 08-01-2009, 07:46 PM
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JoeLaunchman JoeLaunchman is offline
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Another, more esoteric, question in this discussion is: When is the same rocket no longer the same rocket? If you replace the parachute, shock cord, shock cord mount, nose cone , and engine mount, and replaced a couple of broken fins, can you still count it toward the total number of flights for that rocket?

It's like the cliche about "Grandpa's Hammer." Well sure, he's replaced the handle 3 or 4 times and he's replaced the head 3 or 4 times, but it's still the same old hammer he's always had...or is it?
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  #10  
Old 08-01-2009, 08:10 PM
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Royatl Royatl is offline
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Quote:
Originally Posted by JoeLaunchman
It's like the cliche about "Grandpa's Hammer." Well sure, he's replaced the handle 3 or 4 times and he's replaced the head 3 or 4 times, but it's still the same old hammer he's always had...or is it?


Yea, but our bodies essentially get replaced every year, so are we not the same person as we were last year?
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