Protecting the "smoking end" of your rocket...

I have coated the inside of the body tube near the motor with CA. This seems to work on smaller motors (upto about a G or so) I have also lined the inside with fiberglass. This seems to work best with F/G to I or so motors. J motors and above just get too hot for almost all the things I've tried. I almost always have the motor extend past the body tube by a 1/2 inch and use JB weld on all connections for motors that big.

High-temp automotive paint might work, but I thought it took a special curing process to work correctly (have to bake it on) and so I've never attempted it.

-Aar> What do you guys and gals do to protect the aft end of your rockets (mostly

I'd start by checking your blast deflector, most of the aft end damage is from blowback at ignition. Even the best high temp paints aren't going to protect against incendiary particles in that temperature range.

Some time with a pair of tin snips and a cheap-o thin walled stainless steel mixing bowl would yield a design that would divert hot gasses and particles without the ricochet effect.

Mike Doyle

Bruce Sext> What do you guys and gals do to protect the aft end of your rockets (mostly

One thing I have done on a couple of rockets that has been fairly successful is to use a disposable heat-sheild made of heavy duty aluminum foil (the kind used in ovens). This works well on fairly large rockets with a flat aft end where the rear centering ring is slightly recessed inside the body tube. Cut out a ring of foil that will fit on the centering ring between the motor tube and the body tube. You can also have tabs that will protect the sides of the body tube and motor tube. Hold it in place with either masking tape or whatever you are using for motor retention (in larger rockets). This sheild will last for several flights. When it starts to deteriorate you just replace it with another one. I make templates of the sheilds and cut out spare ones to carry in my range box.

Jonathan

----- Jonathan Sivier Secretary, Central Illinois Aerospace jsivier AT uiuc.edu NAR #56437 Tripoli #1906 CIA Web Site:

I let get yucky. If it bothered me, i'd put an aluminum plate on it. I have one rocket that's flat black. It isn't affected by that.

Phil

use a standoff on your launch rod.

our club uses spent Estes engine casings. hardly any liftoff damage. bet it would be non-existent if we stacked two of them.

also, we use angled blast deflectors on the HPR stuff. absolutely no issues

High Temp RTV. You can buy it at the local hardware store. It has a copper base and is rusty colored. I actually have a motor retiention tail cone I made out of wood and foam. The motor sits back behind the exit plane of the tail cone by about 3/4 to 1 inch. The RTV works great on the ID of the cone. We use the same stuff on real rocket test stands to cover exposed bolts on tooling that sits behind the nozzle exit cone. And I'm talking about a 60 inch dia solid booster that makes the concrete surface pop like popcorn and the steel deck plate radiate at about 300F for 20 minutes or so after the static fire test. Just apply the RTV the day before your launch with a putty knife or similiar object. You could try painting it on with a stiff brush. I just use my finger.

I also just found a company that makes high temp coatings that you paint on good up to 2600F. They sell a roll of insulative tape consisting of aluminum and fiber glass layers you could try.

I always use a standoff - maybe I just need to set it higher from the blast deflector. I would prefer angled blast deflectors but unfortunately I don't have a choice with the launches I attend.

take a pie pan (metal one from the dollar store, not a foil one) and bend it into a taco shape, or maybe a bit less. one hole in the center and you have an angled blast deflector.

for the more adventurous.......

take the same pie pan and load a rocket with an Estes D12 that has been frozen/thawed and then left in a car on a few sunny weeks. deflection angle will vary, but can make for some interesting launch footage.