another "wow" for christmas

[mobile_bob]

this one looks to be much more thought out, and probably just as dangerous as the sledgehammer stunt

http://www.funnyhub.com/videos/pages/cool-sawdust-explosion.html


sure wouldn't want to be cruising over with a light aircraft, helicopter or balloon about the time that thing went off!

bob g

[MacGyver]

Yeah, sawdust can be lots of fun.
Some years ago a friend and I built a mortar that launched (and ignited/exploded once airborne) a 5 lb sack of flour.
Picture a 30' diameter fireball that bursts 150' above ground. It makes an awesome deep concussion that you can feel through your whole body. 

We could launch one from the back of a pickup truck.   

Those were the days...

[mobile_bob]

after witnessing some of the crap we did as kids, and now the even more bizarre stuff i see on utube
it really is no wonder that no other country wants to invade the good old usa!


good lord, some of these good ole boys can figure out more ways of killing each other sitting around drinking beer,
just imagine what they could do if they had a serious perceived threat!!

wouldnt take much to make that saw dust cannon turret mounted, and semi automatic
i bet with an afternoon and a group of guys they could remount that thing on a platform swivel
and get a round off ever 10 seconds or so.

wouldn't want to be an opposing force coming up a wooded lane thinking i got this one on the hip!

that thing would ruin you whole day!!

bob g

[Stan]

My first solo flight after 5 hours of instruction went like this.  Instructor said OK, that's enough circuits for today, land and let me out.  He then told me to take it easy and make it a long circuit by myself.  Being ultra nervous I took off and took my time climbing.  Without remembering about the 7 sawmill, forced air, smokeless 60 foot high sawdust burner operating just South of the airport, I suddenly found myself almost inverted less than 1000 above the ground (left wing got caught in the updraft).  When I landed a few minutes later, still shaking, I found my instructor and his buddies still laughing, tears streaming from their eyes.  They congragulated me on the "best" recovery they had ever witnessed!  I'm still mad at them all.    (that was 1974)

No, you wouldn't want to be flying over the sawdust explosion!
Stan

[oliver90owner]

That seemed like a fast burn rather than an explosion.  The flour is a better idea, like powdered coal.

I remember the custard powder explosion that severely mis-shaped the top floor of the General Foods factory in Banbury in the 70's. A hopper/silo over-filled and the corn flour dust exploded in predictable fashion. 

We also had a retro-fitted fan that exploded several times on coal plant shut-down.  Air to fuel ratio passed through the danger zone and bang, one tulip shaped fan housing.  All they did was put a cage around it (to prevent anyone sitting directly on the fan?).  Like most things, they addressed the symptoms, not the disease.

Our old coal plants all had sand poured onto any flat surface until it ran off, so that if there was an explosion from the coal mill, there would not be a secondary explosion (of the whole building) as the coal dust showered down from any perch, high above.  Not sure if it was ever tested.....

Regards, RAB

[billswan]

On the American tv show called mythbusters , there was a clip where a simaler device was made and discharged and of course it worked something like the device linked to on  mobile_bobs first post. But in the shows most notable love for big explosions they than built another device that was many times larger, had a vee shaped ss cone hooked to 4 large oxygen type tanks manifolded together into a quick dump valve. The tanks only had compressed air in them not oxygen. than they filled the cone shaped hopper with some type of I believe coffee creamer power, must have been 200+ lbs of the stuff. took a fork lift to get the pallet full of powder up above the device to fill it with the powder the hopper had a vertical part and over all height was  about 8 foot I would guess. They used a road flare for ign. just like the others.  And yes the fire ball was huge Iam sure if viewed in person it would be a awesome sight!!!

[rcavictim]

That seemed like a fast burn rather than an explosion.  The flour is a better idea, like powdered coal.
Regards, RAB

An explosion is a burn where the speed of propogation of the flamefront is greater than the speed of sound.  What is seen in the sawdust video is called a conflagration.  Subsonic burn.  Impressive fireball!

[Geno]

Here's another.

http://www.youtube.com/watch?v=kHpBComsngQ

Thanks, Geno