Question on nitrate dope and flammability

You *did* give the dope a chance to evaporate off all of the volatiles?

I sometimes tape a square of tin foil on the top of the wing that would see the exhaust heat. Aside from providing flame barrier, the crinkled foil actually sort of helps keep the top path boundary layer from separating (according to the theory) and improve lift (classified secret). Having mentioned that, now I'll have to shoot you... (JUST KIDDING!!!!!!) :-P

Yes, I did - and I knew someone would ask me that! The balsa (1/8" thick for my test pieces) went up like it had been dipped in gasoline, the flame spread that quick.

Since this is a scale model, I can't do that - on the outside. But that idea may work great for the inside, thanks for that tip!

That's why I always bungee launch through a cloud of gnats whenever possible, the bug bodies stuck to the leading edge acts like a turbulator and reduces my stall speed to nil! Sometimes if there's a little life left in 'em, they keep buzzing their wings and that helps to add even more lift. ;-)

Nitrate Dope = nitrocellulose lacquer = nitrocellulose in a solvent, often acetone

Nitrocellulose is better known as smokeless gunpowder. Yes, it burns.

Nitrocellulose lacquer was used to finish furniture. It is sometimes still used for some musical instruments.

NC lacquer is still used to make a waterproof seal, such as on ematches.

A little googling will provide answers to your questions.

And stickers. Make sure you add cool stickers. They improve lift.

Chuck W Sharc, NAR Section 613

Sharc, the section where two out of three certification flights always work just fine!

And if you made a say BOMARC BG and it did ignite ala Hindenburg. It would not only go down in flames but imagine the video rights and speaking fees! Just kidding of course we all make mistakes that destroy our rockets without adding boosted flambe' to the festivities.

Yep, I know.

I tried googling, but came up empty-handed. Hobby-wise, nitro is mostly used by the free-flight crowd, not much need for flameproofing there. It's also used by some jetex'er's, whom I thought would have a plethora of ideas on flameproofing nitro doped finishes, but nada.

It just doesn't seem like the whole issue of flameproofing nitro doped finishes has garnered a whole lotta discussion amongst the rocketry crowd.

flammable,

if it ever does

I've used nothing but Nitrate for dope and tissue finish on my gliders for at least 2 decades, with no increased flammability issues ever. If the exhaust hits the wing, it's gonna burn, nitrate dope or not. So keep the direct exhaust off the model. A little epoxy and or aluminum foil in key locations near the motor is all I've ever used to flameproof my models.

Thanks Bob, that's reassuring. Do you ever finish with paint over the doped finish, or just dope only?

Get serious! These are competition BGs and RGs.

Refer to