Engines in a hot car on a hot day

[DirkTheDaring]

Heading down to Sod Blasters tomorrow. It may hit 104 degrees (F). While I doubt this is a serious safety issues, I may as well ask - it's going to get pretty hot in the car when it's parked. How likely is this to ignite a BP or composite engines? I'm not overly worried about damaging the engines for the long term, they should get used up by the end of the event, but during those hot days, any risk?

 

[heada]

It wont hit the auto-ignition temp (200+ degrees F) but performance is directly related to propellant temp. I don't remember if you get a boost or a drop with higher temps but it's something to be aware of.

 

[boatgeek]

It wont hit the auto-ignition temp (200+ degrees F) but performance is directly related to propellant temp. I don't remember if you get a boost or a drop with higher temps but it's something to be aware of.

Composite engines burn faster/with more thrust when warmer. I don't know how BP reacts to temperature. It's probably a good idea to leave your windows open. I've never heard of a security/theft issue at a club launch.

 

[SolarYellow]

Smokeless powder in firearm ammunition burns considerably faster, generating obviously more pressure and recoil, if it is hotter from being kept in a closed car. Don't know for sure about black powder, but I'd assume it's in the same direction, since most chemical reactions progress at a higher rate with higher temperature. I'd worry about CATOs. Might take a mini cooler with something cool or cold in it, but not ice that could create moisture issues. Serious rifle shooters sometimes do that in hot weather.

 

[Zeus-cat]

I keep my motors in the trunk or on the floor of my car if it's hot. Windows down or at least partially open and motors out of direct sunlight.

 

[Sooner Boomer]

We've had launches over 104. I don't think it will be a safety issue, but keep the engines/reloads in the shade as much as possible. I don't think you will be able to measure any performance change, given the variability inherent in the product.

 

[lakeroadster]

Per the instructions that come with Estes black powder motors:

Keep engines away from fire or sparks so they won't ignite by accident. Don't freeze or put them in a place that gets warmer than 140 F. (60 C.) This or moisture can damage them.​

 

[Hobie1dog]

you'll be fine, keep them in some shade.

 

[Tom Flint]

They will not ignite from being in a hot car, but for black powder motors the propellant could thermally expand enough to stretch the casing and cause the propellant to delaminate from it. This could cause a cato when the motor is subsequently fired.

 

[roc_boy]

Yeah, I typically have mine in some kind of box, one of many boxes, and I don't leave anything in the car that I don't want to melt - I put everything in the shade of something.

 

[gldknght]

Actually the autoignition point for black powder is ~867 degrees F.

( http://www.sciencemadness.org/smwiki/index.php/Black_powder#:~:text=Gunpowder has a pH of,temperature of 464°C. )

It most likely won't get that hot in your parked car.

But to prevent temp cycling damage, just keep your motors in the trunk.

 

[SolarYellow]

Trunks get hot, too.

 

[gldknght]

Yep, but typically not nearly as hot as the interior of a car. Color of the trunk lid can make a difference. Mostly, though, the temp of objects in the trunk changes more slowly, due to not being exposed to direct sunlight.
You can wrap a cold pack in a thick towel to keep any moisture from getting to the motors, then place that towel on top of the container of motors inside a cooler. Don't pack the cooler with ice. You don't want to freeze your motors either.