XM-3 Olfactronic Personnel Detector

rotorwash

Sergeant Major
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What do we spend the taxpayers money on? In this case it was a typewriter size box carried aboard a slick by some headquarters type butterbar giving him an inflated dose of self importance. Then the pilot arrived with a weird grin on his face and looked at me like, "You ain't gonna believe this." I didn't.

The box the looey was holding sniffed the amount of ammonia present in the air as the helicopter flew at treetop level. Seriously. Unwashed bodies give off amounts of ammonia. Large numbers of unwashed bodies give off large amounts of ammonia. If we flew through the air with our magic box we could detect this ammonia and then call in artillery on the locations. There was also an infantry model, the XM-2, that looked like a Hoover vacuum cleaner. It's probably still laying in a rice paddy somewhere.

After while these missions became routine and even gained a name, people sniffer flights. It involved said slick with said butterbar and said machine flying low level back and forth like mowing a lawn. Now because the slick was at low level, gunships must be present for protection, a low level slick is vulnerable. However, the only way the mission would work was for one gunship to be at about 1000 feet plotting the sniffer's course on a map and keeping him on course with the other gunship tailing the slick at about a mile. Gunship crews get nosebleeds at that altitude. As we chased each other through the sky searching for the elusive smell of ammonia, the butterbar would holler "HOTSPOT" every time the needle on the amount-of-ammonia-in-the-air guage hit a certain level. The gunship pilot with the map would make a mark on the map that would later be forwarded to the artillery. Give them something to do in their spare time, right you cannoncockers? We always felt a nagging need to apologize to the artillery for those maps.

Sniffer missions went from novel to the mundane until one day we were short of aircraft so we were loaned one from a sister company. Unfortunately, the aircraft came with a pilot who was not enamored with Duc Pho. In fact, he had heard all the horror stories about how difficult and dangerous an AO it was. News to us.

When he was told he would fly a sniffer mission, the hair on the back of his neck stood up to the point it shoved his helmet down his nose. He was terrified. But, being the trooper he was he loaded self important butterbar and mysterious box in back and took off. At the end of his first run he was five miles ahead of the gunship and gaining. Now the book says that a C model gunship can outrun a D model slick at the rate of about fifteen knots an hour. I bet the guys that wrote that book never saw this boy fly.

RW
 
How the hell did this bit of kit work - detecting ammonia from a speeding chopper - wouldn't it get contaminated by helo smells or get its purpose negated by the wind speed?
Did you have any proof that it really worked - looking at the tone of the piece, perhaps not! :?
 
Absolutely none. Nada. Zip.

I think the boffos viewed the rising ammonia smell from a large number of unwashed bodies as akin to a column of smoke rising from a fire. When you fly through the column of smoke you can smell it, so why not ammonia? I'm not sure how they tested it, but my guess is most of it happened at the 19th hole.

RW
 
I thought as much - it gave the guns some practise though!
 
People Sniffers

My buddy Sam Duncan was on a series of these flights out of Danang in 68. He was the REMF assigned to it. He said that it did work some of the time. I thought it detected CO2 not ammonia but I'm no expert. It cannot tell the difference between a herd of buffalo and a regiment of NVA. It only works in areas that are normally free of people when it works at all. He said it had to be recalibrated at higher altitude every day in order to be accurate..
 
I'm pretty sure it was ammonia, but if someone proves me wrong I won't fight 'em over it.

The only place we ever used it was in mountain and jungle areas that were supposedly uninhabited. We most commonly used it in the mountains that seperated us from the Cav's playground in the Bong Song plain.

RW
 
Rotorwash,
Ammonia or Co2 who cares at this point? I enjoyed your post and the memories. Thanks for posting. I think we killed water buffaloes, elephants, and monkeys with this device. You never know what's in a jungle.
 
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