Advice About Disposable Wadding Alternatives in LPRs

[mh9162013]

How much did the baffles for all the rockets you built in that hypothetical year cost? I don't think you're going to average 100 launches/rocket, that seems pretty high.

A baffle that you buy (and not make) is anywhere from $4-$6 or so (for an LPR). Reusable wadding is the same price. But the wadding can be moved from rocket to rocket. So you'd only have to buy one piece of reusable wadding and move it from rocket to rocket (assuming they're the same diameter).

As for the baffles, yes, you'll have to buy one for each rocket. But baffles are supposed to last forever, right (assuming no CATOs or anything)? Or do baffles have shorter lifespans?

 

[smstachwick]

How much did the baffles for all the rockets you built in that hypothetical year cost? I don't think you're going to average 100 launches/rocket, that seems pretty high.

I concur. You’d be lucky to get more than two or three dozen flights unless you really baby it. 100 is a feat, and there will be a lot of repairs, clean-outs, component swaps, etc. Those all cost you something. If breaking even takes that many flights and eats up that much of your supplies, your savings margin isn’t that great and it was probably eclipsed by other costs elsewhere.

Just to illustrate, consider this: You can save considerable money over single-use motors by using reloadables, but even then that’s at least two and possibly as many as half a dozen flights on a set of hardware before you break even. I’d consider that about my limit for a switch based solely on economics, as I’ve had my fair share of rockets disappear or land in the water (either way it would be required or desirable to get new hardware) long before then. If the break-even point was at 100 flights, I don’t think people would fly reloadables all that much. They’d be a novelty or a developing technology, not the potential money savers that make them so attractive once you get out of the LPR range.

On the other hand, perhaps you’re considering alternates for some other reason (sweat equity and simplicity of preparation are valid), so what I say here may not be as important to you or even apply at all.

 

[mh9162013]

You’d be lucky to get more than two or three dozen flights unless you really baby it. 100 is a feat, and there will be a lot of repairs, clean-outs, component swaps, etc.

Rockets can be "retired" for any number of reasons: motor blows up, recovery system fails (wadded parachute, ejection charge failure, etc.), rocket gets lost, a tree eats it, etc. But how many flight can a typical LPR rocket have before it's "retired" because it simply "wore itself out?"

My goal with my next major rocket build is to build a rocket that can last as long as possible and fly as time and cost efficiently as possible. So I'm looking for products and solutions to help meet that goal. I assumed that a properly built baffle would last as long as the MMT in the rocket and a peice of reusable wadding would last at least 50+ launches. But maybe I'm wrong about these two options?

 

[smstachwick]

Rockets can be "retired" for any number of reasons: motor blows up, recovery system fails (wadded parachute, ejection charge failure, etc.), rocket gets lost, a tree eats it, etc. But how many flight can a typical LPR rocket have before it's "retired" because it simply "wore itself out?"

As in, how long will a rocket last under perfect storage, flight, and recovery conditions, every time, for the duration of its lifespan?

I’m going to offer my answer as “nobody really knows” because perfection does not exist in rocketry. At some point, somebody or something is going to mess up and the proverbial fan will suffer a turd strike.

 

[mh9162013]

As in, how long will a rocket last under perfect storage, flight, and recovery conditions, every time, for the duration of its lifespan?

I’m going to offer my answer as “nobody really knows” because perfection does not exist in rocketry. At some point, somebody or something is going to mess up and the proverbial fan will suffer a turd strike.

Ok, fair enough.

How about this: how long will a properly built baffle last assuming normal motor and rocket operation?

 

[Ez2cDave]

As for the baffles, yes, you'll have to buy one for each rocket. But baffles are supposed to last forever, right (assuming no CATOs or anything)? Or do baffles have shorter lifespans?

When building baffles, "paint" the inside with JB Weld, thinned with Acetone. It gives a great, long-lasting, high-temp resistant protective coating !

Dave F.

 

[lakeroadster]

As for the baffles, yes, you'll have to buy one for each rocket.

Or build your own... for pennies on the dollar.

... how long will a properly built baffle last assuming normal motor and rocket operation?

The life of the rocket. Build it as a coupler and it can be used on multiple rockets also.

 

[smstachwick]

Ok, fair enough.

How about this: how long will a properly built baffle last assuming normal motor and rocket operation?

I can’t speak for the average of the entire body of rocket builders, but mine seem to be hovering at what I’d estimate to be around 12 flights. Maybe lower than that, I don’t actually know.

Then again, I did get back into the hobby pretty recently, building Estes kits mostly stock but still wanting to try a little bit of everything, mainly experimenting with 2-stage conversions at the moment. I’m betting those with more consistent experience will have averages much higher than that.

So far I’ve lost:

A Firestreak SST due to damage to the plastic snap pins holding the body casing together. I had underpowered it on a 1/4A3-3T motor and blasted the casing apart on simultaneous impact/ejection some time previously.

A Mosquito that I never saw again after daring to shove a massive 1/2A3 motor in it in my local schoolyard.

A Gnome that bent under power.

Another Gnome that got eaten by a giant tree.

A Star Trooper that I had unknowingly loaded with a defective A10-3T, date code D21 0521. Estes replaced the pack it came in, free of charge.

A Luna Bug that I had converted into a booster for another Luna Bug, the booster being cooked by a failed separation.

A Phantom that got cooked after almost a dozen flights despite being meant to be a teaching aid instead of a flying model rocket.

Another Phantom that cracked along the tube after I accidentally glued the parachute to itself during a rushed night flight prep and decided to fly it with only nose-blow recovery.

A Generic E2X that survived a water landing and then crashed nose-first after a staging failure on a separate flight, bending the body tube. That rocket was retired, it was an act of mercy.

I have so far not lost:

The booster that the first Gnome was converted into.

The booster for the Star Trooper that CATOed

The replacement Luna Bug booster and its matching sustainer. Several flights for each stage.

The booster for the Generic E2X.

My Goblin, converted to two-stage. 9 flights by my count.

My Hi-Flier XL. Currently in sick bay with a bent body tube. Repair planned, booster under construction. Survived water landing and being stepped on with easily repaired damage. 9 flights.

My Star Orbiter. Generally good condition, minor cosmetic damage to the nose after it separated, thrust damage to the spiral seam as is typical for this kit. 12 flights, including 2 on E23T reloadables.

My remaining fleet from when I was a kid. Uncountable flights, many good memories, some of which included losing rockets in spectacular fashion.

UPDATED: Flight totals corrected

 

[mh9162013]

The life of the rocket. Build it as a coupler and it can be used on multiple rockets also.

That's what I assumed. But it seemed like certain people were implying that my assumption was wrong.

 

[mh9162013]

Build it as a coupler and it can be used on multiple rockets also.

How? Wouldn't gluing it in make it a permanent install? Or are you saying that when you retire a rocket, you can salvage the baffle and use it in another one?

 

[SharkWhisperer]

I can’t speak for the average of the entire body of rocket builders, but mine seem to be hovering at what I’d estimate to be around 12 flights. Maybe lower than that, I don’t actually know.

Then again, I did get back into the hobby pretty recently, building Estes kits mostly stock but still wanting to try a little bit of everything, mainly experimenting with 2-stage conversions at the moment. I’m betting those with more consistent experience will have averages much higher than that.

So far I’ve lost:

A Firestreak SST due to damage to the plastic snap pins holding the body casing together. I had underpowered it on a 1/4A3-3T motor and blasted the casing apart on simultaneous impact/ejection some time previously.

A Mosquito that I never saw again after daring to shove a massive 1/2A3 motor in it in my local schoolyard.

A Gnome that bent under power.

Another Gnome that got eaten by a giant tree.

A Star Trooper that I had unknowingly loaded with a defective A10-3T, date code D21 0521. Estes replaced the pack it came in, free of charge.

A Luna Bug that I had converted into a booster for another Luna Bug, the booster being cooked by a failed separation.

A Phantom that got cooked after almost a dozen flights despite being meant to be a teaching aid instead of a flying model rocket.

Another Phantom that cracked along the tube after I accidentally glued the parachute to itself during a rushed night flight prep and decided to fly it with only nose-blow recovery.

A Generic E2X that survived a water landing and then crashed nose-first after a staging failure on a separate flight, bending the body tube. That rocket was retired, it was an act of mercy.

I have so far not lost:

The booster that the first Gnome was converted into.

The booster for the Star Trooper that CATOed

The replacement Luna Bug booster and its matching sustainer. Several flights for each stage.

The booster for the Generic E2X.

My Goblin, converted to two-stage. 9 flights by my count.

My Hi-Flier XL. Currently in sick bay with a bent body tube. Repair planned, booster under construction. Survived water landing and being stepped on with easily repaired damage. 7 flights.

My Star Orbiter. Generally good condition, minor cosmetic damage to the nose after it separated, thrust damage to the spiral seam as is typical for this kit. 10 flights, including 2 on E23T reloadables.

My remaining fleet from when I was a kid. Uncountable flights, many good memories, some of which included losing rockets in spectacular fashion.

Hah! Nice reacap!

The topic of max flights/rocket before retirement or loss definitely deserves it's own thread. I'll go start one...

 

[Jerry F.]

I like to use baffles in most of my LPR/MPR rockets - so much easier to prep for flight!
I prefer the baffles from Rocketarium...BT20 through BT80 for $4-6 (that's Cdn $'s too!!)
But I also use dog barf in any rockets that I haven't installed the baffles in...

 

[lakeroadster]

How? Wouldn't gluing it in make it a permanent install? Or are you saying that when you retire a rocket, you can salvage the baffle and use it in another one?

Don't glue it... screw it! ......through the BT wall.

 

[Grant_Edwards]

How about this: how long will a properly built baffle last assuming normal motor and rocket operation?

I can’t speak for the average of the entire body of rocket builders, but mine seem to be hovering at what I’d estimate to be around 12 flights. Maybe lower than that, I don’t actually know.

12 flights is how long your baffles are lasting? Or how long your rockets are lasting?

 

[MidOH]

I build LPR's as often as I fly them. So it's hard to tell.

My baffle is just two couplers, three pieces of scrap balsa, and some epoxy. No real cost.

 

[mh9162013]

Don't glue it... screw it! ......through the BT wall.

Do you use screws even for BT-50 LPRs?

 

[MidOH]

Heck no. Just glue it in. There's no point in a reusable baffle.

 

[mh9162013]

Heck no. Just glue it in. There's no point in a reusable baffle.

Why not? Because they can last forever?

 

[MidOH]

I'm using that coupler to stiffen the tube. Often one of them is included in the kit to join the tubes. And it's just a cheap piece that I make in 30 minutes.

With the extra coupler, a Highflyer XL's tube is quite stiff. The long fins, then 2 couplers. Tough little rocket.

 

[rharshberger]

Why not? Because they can last forever?

They dont last forever, most rockets however dont survive long enough for them to wear out. Just like a nomex a baffle is damaged a small amount every time the ejection charge goes off, eventually nomex's wear out/burn through, eventually baffles wear out too.

 

[mh9162013]

They dont last forever, most rockets however dont survive long enough for them to wear out. Just like a nomex a baffle is damaged a small amount every time the ejection charge goes off, eventually nomex's wear out/burn through, eventually baffles wear out too.

If they don't last forever, how long do they typically last? I get the feeling no one really knows?

 

[Grog6]

Sorry for being unclear about the body shop comment; yes, blown airbags are a great source for varied weights of fireproof cloth. Most places hace to pay to get rid of them, there's some toxic stuff inside; residual calcium or sodium hydroxide, iirc.
Be sure to wash them out, and don't breathe or get the dust on you.

 

[lakeroadster]

Do you use screws even for BT-50 LPRs?

Sure.. Use small screws. Think outside the box.
<--- But then again, I'm Oddroc Scum

 

[ZoomieG]

If they don't last forever, how long do they typically last? I get the feeling no one really knows?

1 - They don't last forever
2 - No one really knows how long they last
3 - Rockets typically don't last long enough or get launched enough to really find out

As one data point, Chris M. took apart a Centurion a number of years ago, and posted the 'autopsy' on his blog. It looks pretty sooty and gunked up after 15 flights, but still perfectly functional.
http://modelrocketbuilding.blogspot.com/2013/01/centurion-autopsy.html

 

[mh9162013]

1 - They don't last forever
2 - No one really knows how long they last
3 - Rockets typically don't last long enough or get launched enough to really find out

As one data point, Chris M. took apart a Centurion a number of years ago, and posted the 'autopsy' on his blog. It looks pretty sooty and gunked up after 15 flights, but still perfectly functional.
http://modelrocketbuilding.blogspot.com/2013/01/centurion-autopsy.html

Legit question: do you think anyone really cares? I'm thinking about doing some tests that would involve 25+ engine launches in a generic 3FNC/4FNC BT-50 or BT-60 LPR rocket and see how the components hold up after a certain number of motor ignitions. I'd have to figure out how to build it, ie what glue to use, how much reiforcing to use, what materials to use, etc.

The biggest issue is cost for the engines. But if there's enough demand, I'm more than happy to do the experiment.

I'm going to make another thread...

 

[smstachwick]

12 flights is how long your baffles are lasting? Or how long your rockets are lasting?

That’s my estimated rocket flight count, excuse me. A properly built baffle will last the life of the rocket as I understand it, which can nevertheless be quite short if you’re like me and continually trying something new.

 

[DAllen]

Because dog barf is sooooooo expensive at $1.30 or so per YEAR.

 

[Daddyisabar]

I'm coo-coo for Decopuffs! Same thing as Quest wadding only in many colors. 300 sheets lasts long time for LPR. Bulk packs for use on parade floats.

 

[beeblebrox]

Another reason for baffles is that except for dog barf that seems to be bio-degradable, wadding=litter. I have heard of good luck with cabbage tho and wild life can eat it. another thing to think of is with either a baffle or even dog barf there is not a good seal between the ejection gas and the parachute, thus gasses go around the chute. Nose cone inertia not being enough to pull the chute out. A bit larger charge would help here. OR... a piston. trying that later. Got that idea from Doug Frost's rocketry golf rockets. Golf course owners did not want anything ejected out on the golf course regardless of bio-degradability. I got lucky and discovered that the Emma Kites spool for 100lb kevlar line fits perfectly into a 2.6" tube...

 

[DAllen]

Dog barf is biodegradable. It’s totally fine to use.