Has anyone tried the Qualman Rocketry baffles or laundry shelves?

Baffles: https://www.qualmanrocketry.com/Baffle BT plywood.html
Shelves: https://www.qualmanrocketry.com/Divider BT plywood.html

They seem nicely designed, simple, and inexpensive. Good use of a laser cutter. Anyone used them?

I'm particularly interested in the BT50 baffle for the Starship Avalon, because it'll solve a few problems for me and anyway I find stuffing dog barf into a BT50 to be... well, annoying at best. I've never used any baffle before.

Yes I am aware it is possible to build your own baffles and shelves. I'm specifically interested in anyone's experience with the Qualman units.

Thanks!

I bought a few of each for some projects in the works. The baffles are a little different but well made. I put a shelve in a bt60 that is being rebuilt. should work fine. The parts are well made from nice stock. Good laser work. I see no reason the parts will not work fine.Price is right! Tim Thomas

I've never used them, but now that I know they exist, I likely will. I find using baffles very convenient, esp. on low power kits.

Yes, they look inexpensive and worth the cost. One nice feature of these vs. baffle using tube couplers is that these should be easier to glue in place, vs. having to worry about the glue on a coupler "seizing" before you can get the tubes meeting properly.

I've thought of using baffles built as tube couplers for my Star Orbiter and STM-12 since they need a coupler to join the tubes. Has anyone had an issue with stability because of the the extra weight at the center of the rocket? I could also install one of these shelves to keep my recovery system more nose forward.

Do baffles also eliminate the need for any recovery protection or do you still add some just in case? This baffle system is all new to me, and I like the idea.

Todderbert said:

I've thought of using baffles built as tube couplers for my Star Orbiter and STM-12 since they need a coupler to join the tubes. Has anyone had an issue with stability because of the the extra weight at the center of the rocket? I could also install one of these shelves to keep my recovery system more nose forward.

Do baffles also eliminate the need for any recovery protection or do you still add some just in case? This baffle system is all new to me, and I like the idea.

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I still use a bit of recovery wadding and dog barf in all my rockets with baffles, in some like my Mean Machine the ball of wadding lasts multiple launches since the gas is slowed a bit by the baffle. Baffles work, but they can also break, the red caps from AT reloads have been known to break the bottom baffle plate of some baffles.

I'm interested in those baffle assemblies. Are they glued in or removable?

Pass on the shelves. A cardboard ring with a stringer has worked for me so far

looks interesting...

Sorry no pictures, but...

I bought the cardboard centering rings from estes (003179), then machine copied them to heavy card stock.
I cut the ring that fit the BT i was using, then tack glued to 1/8" ply.
Used a craftsman scroll saw (I've used a drill, file, and sandpaper too) to cut out the ring, then sand to fit.
Use a drill bit to open the ring up, leaving some "meat" in between the holes so it doesn't come apart on you.

How you install them depends on if they will carry weight during recovery.

The coolest and cleanest install I saw was 8 yrs ago...

Here's an OR file of it (as I remember it, you've probably seen this before, but for those who haven't)





View attachment Coupler with LaundryShelf.ork

I've also seen this system glued into an extra long coupler, then (at the time) the coupler installed inside the bt and was held in place using counter-sunk 4-40 screws.

hope it helps

fm

Nytrunner said:

I'm interested in those baffle assemblies. Are they glued in or removable?

Pass on the shelves. A cardboard ring with a stringer has worked for me so far

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They're glued in. I'm most interested in the baffles, was just curious about the shelves.

Those Qualman Baffles sure look good. I wonder how they compare, weight-wise, to other baffles that use card stock rather than light-ply, especially in the larger BT sizes? I'm trying to decide whether or not I want to go this route on the QCC Explorer I'm currently building. It would seem to be a good candidate for one though.

If you want to combine an order to save on shipping let me know (re-sending them between us should be quite cheap, although it's possible it doesn't make any sense to do this). Trying to figure out how to dilute shipping has been what's kept me from ordering these until now; don't want to pay $5 to ship $2 or $3 worth parts.

I think I'd probably go the home made route this time, if I do it at all. You're right though, paying more for shipping than what the part you want costs doesn't make sense.

TangoJuliet said:

Those Qualman Baffles sure look good. I wonder how they compare, weight-wise, to other baffles that use card stock rather than light-ply, especially in the larger BT sizes?.

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I just weighed some of the larger ones, and the approximate weights are:
BT-80: 20g
BT-70: 14g
BT-60: 11g

They aren't really heavy, because they are made from 3-ply lite-plywood instead of 5-ply aircraft plywood.

I'm not sure how they compare to cardstock baffles. I experimented with cardstock baffles a while ago, and wasn't satisfied with the results I was getting. They seemed to be much weaker, and seemed to fail enough that I didn't trust them. Of course, that was regarding the designs I tried. There might be other card stock baffle designs that are more robust.

Actually, I gave up on baffles after that, until Brian Swanson at BRS hobbies and I discussed alternatives, and came up with designs which don't require a tube coupler. He carries the baffles at his online store as well, www.brshobbies.com.

As for whether wadding is still required, it kind of depends upon your construction and launch techniques. I built a test fixture for experimenting with the baffles, and found that if I used really lightweight plastic as my parachute material - read that as dry cleaning bags - they could suffer from slight damage from the heat. Also, if the baffle is close to the engine, I think more heat gets through. I still use a small layer of wadding with the baffles, just because I have an old-school fear that plastic is still exposed to hot gasses. However, I am very sure that the baffles retard the motion of any hot debris - such as burning BP or plugs - so that the parachute and shock cords are much safer.

TangoJuliet said:

You're right though, paying more for shipping than what the part you want costs doesn't make sense.

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If you want, we could swap shipping cost and part cost. Five dollars or so for parts and 2 dollars or so for shipping might sound better.

I am totally kidding about that, because I thought it sounded funny.

I am still trying to figure out this shipping stuff and how to avoid the very problem you are mentioning with small orders.

DavidQ said:

I am still trying to figure out this shipping stuff and how to avoid the very problem you are mentioning with small orders.

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The only way around it really is to avoid small orders - which is a plus for you :wink:; I'll see what I can do.

For me, it's like using an ATM for a cash withdrawal that's outside of my banking system and charges usage fees/penalties. If I have to use one, I try to withdraw as much as is allowed, to offset the fee. Otherwise I try to get cash back on purchases using my debit card, with no penalty.

I have tried to use the baffles as anchor points in the past. Card stock will not work, and light ply makes me uneasy. Buy with this design, you can epox your cord down the main support, a much better idea. I have 3 new rockets ready to go after paint. I will report back on how they worked. So far I think these new baffles are great. I am going to buy more of them. Tim

Thanks David for chiming in here. Any plans to make one of these for Estes 2" BT?

neil_w said:

Thanks David for chiming in here. Any plans to make one of these for Estes 2" BT?

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I'm always looking to expand the offerings. I think the pro series would be a good addition.

That 2" BT would be the Cosmic Interceptor?

Cosmic interceptor and the Trajector, maybe others. Just pondering since both of those are in my near future.

[edit: of course others ]

And I've got a Trajector on the way also!