Will a galvanized steel stove pipe elbow work as LPR blast deflector?

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BMcD

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My personal launch equipment is primarily intended to impress little kids.

I have a Jawstand with a Maker Beam rail, and I am considering using a galvanized steel stove pipe elbow at the bottom as a blast deflector. The idea is that the smoke from the rocket will get pushed out of the outlet in a cool looking way. There is nothing more to it than that - this is purely for visual effect.

I'm happy to invest the $10 and 2 minutes it will take to find out if this will work, but if someone else has already learned the hard way this is a dumb idea I'd love for you to fess up before I have to.
 
Just make sure nothing is going to get caught downstream of the outlet and I don't see any reason why it wouldn't work. I've seen a big plastic bellows looking thing used as a blast deflector before.
 
Vaporized zinc is not a good thing to be around. For low power, the risk is very minimal. For a high power that gets stuck on the pad, it could be just one more thing to worry about.
 
If the motor cato's the elbow could focus and direct some of those hot rocket "bits and pieces" into 1 direction. Which, depending on which way the elbow points, could be very good... or very bad.

heada said:
Vaporized zinc is not a good thing to be around. For low power, the risk is very minimal. For a high power that gets stuck on the pad, it could be just one more thing to worry about.
Click to expand...

Good point. OP can just use bare steel.

Alpha E Engine CATO.jpg
 
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Bare steel sheet metal holds up for a lot of MPR launches (like several hundred). I've got to believe that it would last fine for MPR. If your rocket nozzles are in predictable places, you could also use a black steel plumbing elbow. A 1"-2" wouldn't be too heavy and would last forever.
 
I guess I'm late to this party...

Seems to work fine... I don't think there is all that much zinc in the coating. Interestingly, the interior (after multiple launches) shows zero signs of erosion, and a good coating of carbon. One thing to keep in mind is to wrap these "articulated" elbows with aluminium (METAL) duct tape... An F50 blast can blow them apart!

PXL_20230601_144236325_exported_65002.jpg

The best part of this approach is ZERO backblast damage...
 
The Handbook Of Model Rocketry, which was probably printed before I was born, shows a stove pipe elbow being used as a blast effector.
 
A little off the elbow thing, but we have a 1/4" diamond plate blast deflector, had a cato with a M on it. Put a dent the size of a soccer ball in it. So anything can be damaged if the cause is enough. So just be careful, shrapnel sucks:(
 
DeltaVee said:
I guess I'm late to this party...

Seems to work fine... I don't think there is all that much zinc in the coating. Interestingly, the interior (after multiple launches) shows zero signs of erosion, and a good coating of carbon. One thing to keep in mind is to wrap these "articulated" elbows with aluminium (METAL) duct tape... An F50 blast can blow them apart!

View attachment 603166

The best part of this approach is ZERO backblast damage...
Click to expand...
+1 :goodjob:
 
DeltaVee said:
I guess I'm late to this party...

Seems to work fine... I don't think there is all that much zinc in the coating. Interestingly, the interior (after multiple launches) shows zero signs of erosion, and a good coating of carbon. One thing to keep in mind is to wrap these "articulated" elbows with aluminium (METAL) duct tape... An F50 blast can blow them apart!

View attachment 603166

The best part of this approach is ZERO backblast damage...
Click to expand...

5 gallon bucket, filled 2/3 with water... :dontknow:

520034-5405c56db3190dbf3e2c858024e7dc86.jpg​
 
David Schwantz said:
Also, that ain't no pic of Colorado! There is not anything that flat in CO :)
Click to expand...
LOL... The Eastern Plains of Colorado are just about as flat as one can get. But it doesn't get much press.

I actually use a 5 gallon bucket on my Launch Horse... works great.

Columbine Launch 002A.jpg 000 Launch Horse.JPG​
 
BMcD said:
My personal launch equipment is primarily intended to impress little kids.
Click to expand...

Ha! Ha! Seriously, though, if we want to “pay it forward” and get kids interested in the hobby (and in STEM) then making it fun and impressing them is important. Over the decades, model making and other “maker” hobbies have been in decline. We have to show little kids that model rocketry is just as fun (or more fun) than the constant bombardment of digital distractions they receive.
 
heada said:
Vaporized zinc is not a good thing to be around. For low power, the risk is very minimal. For a high power that gets stuck on the pad, it could be just one more thing to worry about.
Click to expand...
The amount of zinc from a galvanized fixture is unlikely to be a serious problem. A single BlackJack F-motor undoubtedly contains at least as much zinc---possibly several times as much---as is on a galvanized elbow...and it's all burned/vaporized.
 

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