Recovery Wadding: Estes vs. Quest

[Mike]

I've been having some problems with Quest recovery wadding and it not being as effective as the Estes stuff.

I launched six times with Quest wadding, on four flights the streamer/parachute came back completley trashed yet I have a near 100% success rate with Estes wadding. I prefer working with Quest as I find it easier to pack but I don't like watching rockets falling with damaged recovery methods.

I've followed all the reccomendations of how many sheets to use etc. with both types but still have problems.

Has anyone else had any problems?

TIA

 

[KenParker]

Mike:

I pretty much quit using Estes and Quest recovery wadding when I learned about flameproof attic insulation - the blow-in kind. It sells over here for about $6 for a 40 pound bale at home improvement stores.

Another alternative is to use flameproof kevlar chute protectors. They are available in a number of sizes from several vendors.

We've covered this topic before here on the forum, so I imagine others will chime in here or point you to some previous threads.

- Ken

 

[shockwaveriderz]

mike: considering building and using a simple baffle: lightweight, easy to build.....

I also purchase pipe circular screens, and place between the engine block and the top of the engine to catch the hot ejectables allowing only the hot gases to go through the baffle to lower the temps..........


shockie.........B)

 

[gerbs4me]

I haven't had any trouble with Estes or Quest. I use cotton balls when I don't have wadding paper.

 

[rstaff3]

Several points, in no particular order.

Ken is right, there was a previous thread about this subject. I posted a baffle plan and Milo graciously cleaned up my ascii art which got messed up. You might try searching for that and other threads.

For most larger rockets I have moved to chute protectors. Giant Leap and Pratt Hobbies are two sources. I have only bought from Giant Leap. I also was lucky enough to score a couple of used card air bags. A guy at our club disposes of these for a living. They make great protectors and I've now used them down to BT-50.

When I use wadding, I like to use a small piece of Estes wadding with some 'dog barf' wadding (the technical name for the attic insualtion stuff) rolled in it, and then throw in a bit bore dog barf. I've done this up to BT-60.

 

[Mike]

Originally posted by shockwaveriderz
I also purchase pipe circular screens, and place between the engine block and the top of the engine to catch the hot ejectables allowing only the hot gases to go through the baffle to lower the temps..........

Is it acctually the hot particles that damage the chute or the heat of the gas. I've read through the thread on baffles and that was saying the hot particles did the damage. Do baffles cool the gases slightly too as they pass through them or just stop the ejectables?

 

[rstaff3]

IMHO, it is mainly particles but the gas can have some effect. Baffles work because they stop the particulates, and contain the gas. They don't cool the gas, but affect how it mixes with the ambient air. It is the overall pressurization of the tube that causes ejection, not the direct force provided by the ejection charge. That is, an ejection charge pointing rearward would expel a chute just as well.

 

[kgholloway]

Mike,

My experience parallels Dick's. When the ejection charge ignites you get a jet of flame from the forward end of the motor mount tube. The flame consists of hot gasses and particles. If they come in contact directly with the parachute they are certain to do damage.

When you use a baffle, other than a "Chore Boy" type, the particles are blocked and the hot gases are forced to take a longer route from the engine to the parachute compartment. This causes them to mix with the air already in the compartment which slows and cools them.

A "Chore Boy" type baffle uses a tube coupler glued over the motor mount tube and closed by a bulkhead with large holes drilled through it. A "Chore Boy" sponge is inserted in the tube coupler before the bulkhead is glued on. The "Chore Boy" is a pad of stainless steel metal turnings that is normally used for scrubbing out pots and pans. Think of a steel wool pad made with 2mm wide by .005mm thick steel ribbons. Because it is metal it actually cools the ejection gasses by absorbing their heat as well as blocking the passage of hot particles.

Ken Holloway

 

[rstaff3]

I have to agree with Ken, and partially retract what I said earlier. I guess mixing hot gasses with cooler air is in effect cooling them.

But, I never thought about the steel wool baffle helping with heat absorption, but I supose that makes sense. In a fine mesh, there would be a lot of surface area to absorb the heat.

 

[jflis]

The other effect that has to be taken into account is expansion.

Upon ejection, a stream of hot gas is propelled forward. This gas stream has little chance to expande given the speed with which it is being propelled.

The baffle slows this stream down giving the gasses more time to expand. Gasses cool as they expand.

 

[shockwaveriderz]

one of these days I'm finally going to get around to actually measuring temperatrures and such with and without various baffles just to see how hot this stuff is.....and how it cools as it expands into different bodt tube diameters and lengths.....woulod make a great R&D project......surround various tubes from engine block up to to nose cone with thermocouples poking into the body tube around it at say .5" intervals.....to measure the temp vs time......might be interesting...

oh yeah you might want to consider using Nomex paper or Kapton plastic to create your baffles....both are very heat and flame resistant...... or coat the inner body tube walls with epoxy....

shockie... B)


mike: the pipe smoker screens are .750" or 1.0" in diameter so you can use them for 18 or 24 mm engines...I replace them after 1 use as they collect a bunch of junk .........

 

[Mike]

Dick, Ken and Jim:
I was thinking along those lines that baffles make the gas take a longer route and I knew there was no cooling element (or whatever) in the baffle, just clearing that up a bit.

Shockie:
Sounds like a good idea and should give some interesting results.

Thanks