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rocketdoctor99

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We have to launch near residential areas, I don't have a lot of space so limit our launches to A, B engines mostly. Even then we occasionally lose the smaller rockets if we don't account for wind properly. This drives me crazy because Im always worried about the rocket starting a fire after it lands. I know the rocket engines are hot after retrieved but are they hotter than 250 degrees to start a fire, if they land say in a pile of papers?

On future launches Im going to insist on just using streamers for all the smaller rockets.
 

TRFfan

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We have to launch near residential areas, I don't have a lot of space so limit our launches to A, B engines mostly. Even then we occasionally lose the smaller rockets if we don't account for wind properly. This drives me crazy because Im always worried about the rocket starting a fire after it lands. I know the rocket engines are hot after retrieved but are they hotter than 250 degrees to start a fire, if they land say in a pile of papers?

On future launches Im going to insist on just using streamers for all the smaller rockets.
I doubt it is that hot.
 

Incongruent

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There is a temperature limit for the outside of the casing after firing. I can't remember, but I think it's listed in the NAR 40years document.
 

dhbarr

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NFPA 1125
7.4 Motor Casing Requirements
7.4.1 A solid propellant rocket motor shall be designed and constructed so that the temperature of the external surface of the rocket motor casing and fittings, if any, shall not exceed 200°C (392°F) during or after operation.
 
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rocketdoctor99

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thanks I meant to say 451 degrees, interesting info about the casing but the nozzle should be allowed to get hotter during operation? But after a 10+ second decent I bet its a lot less than 400.
 

TangoJuliet

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I think I'd be a little more concerned with smoldering wadding falling out of the sky. But unless conditions are severely dry, as in State Fire Ban(s) like we had in Alabama last summer, I wouldn't be overly concerned.
 

Mugs914

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Agree with TJ... Wadding has a much greater chance of sparking something than residual temp in the motor casing.

For what it's worth, I routinely pull the motors out of my LPR birds as soon as I pick them up on cool days. They are just the right temp to make good hand warmers!
 

Cabernut

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I'd say the biggest fire danger is the eventual cato. Fireballs going everywhere close to the ground.

Actually I recently picked up an IR thermometer gun. I was planning on bringing it to a launch and measuring the casing temp right after retrieval. Both Estes and reload, see what numbers I get.
 

rstaff3

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I'd say the biggest fire danger is the eventual cato. Fireballs going everywhere close to the ground.

Actually I recently picked up an IR thermometer gun. I was planning on bringing it to a launch and measuring the casing temp right after retrieval. Both Estes and reload, see what numbers I get.
That will be useful. I agree with you in that a CATO is the biggest. That and a rocket that hits under power. Of those the landshark is the worst.
 

Steve Shannon

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That will be useful. I agree with you in that a CATO is the biggest. That and a rocket that hits under power. Of those the landshark is the worst.
The most frequent cause of fires for us over the past ten years have been sparks or hot burning pieces of igniters after launch. Yes, a Cato will start a fire but they don't happen frequently. Igniter sparks happen much more often statistically.
 

rstaff3

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The most frequent cause of fires for us over the past ten years have been sparks or hot burning pieces of igniters after launch. Yes, a Cato will start a fire but they don't happen frequently. Igniter sparks happen much more often statistically.
Interesting. I guess I have seen that but, possibly due to the field conditions around here, I haven't noticed that is a problem. Of course, big sparkies are an issue. I personally have never seen much of an issue with a pad fire. There is water nearby and people to run out. Although rare, a rocket landing in a more remote location always seemed to potentially be the worst case as it could be tough to lug water to the site.
 

Steve Shannon

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Interesting. I guess I have seen that but, possibly due to the field conditions around here, I haven't noticed that is a problem. Of course, big sparkies are an issue. I personally have never seen much of an issue with a pad fire. There is water nearby and people to run out. Although rare, a rocket landing in a more remote location always seemed to potentially be the worst case as it could be tough to lug water to the site.
We burned a tenth of an acre once. The fire started 30 feet downwind of the pad while we were all watching the rocket. We were still watching the rocket when one of our group yelled "fire!"
Dry grass burns with almost no smoke and hard to see flames and runs along the ground pretty fast. We don't allow sparky motors unless we have snow covering the ground.

The scariest rocket related fire we had was due to an ejection charge after a rocket came off too light of a rod, weathercocked badly, and ejected on the ground.

We carry lots of water, fire swatters, rakes, shovels, and a backpack pump and we designated one of our group who has lots of experience with wildland fires as our fire marshal.


Steve Shannon
 
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Micromeister

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We have to launch near residential areas, I don't have a lot of space so limit our launches to A, B engines mostly. Even then we occasionally lose the smaller rockets if we don't account for wind properly. This drives me crazy because Im always worried about the rocket starting a fire after it lands. I know the rocket engines are hot after retrieved but are they hotter than 250 degrees to start a fire, if they land say in a pile of papers?

On future launches Im going to insist on just using streamers for all the smaller rockets.
First paper, wood, cardboard ignition temperature is 451degree F. our motors after burnout reach 180-200degrees F, very warm to the touch but will not burn your fingers. This is way it is perfectly legal to eject spent motor casing from our Rockets during flight.
There NO chance of a spent BP motor causing a grass or paper fire.

I have heard of some numb skulls using regular toilet tissue for wadding causing same grass fires, but not from the motor casing rather burning tissue.
 
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