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Ram air
On Jun 1, 11:48 am, wrote:
On Jun 1, 4:35 am, Tina wrote: The Mooney 201 has a ram air port, a half a foot under the prop spinner. The POH tells us it can be opened at altitude for a very modest increase in MP and we find maybe a half inch increase in pressure. The idea of the thing is, if the port is looking right at the air being thrust toward it by the prop (it can't be more than 6 inches or so behind it) as well as the air impact from the airplane's motion the air being 'rammed' into it should effectively lower the altitude the engine thinks it's at. Well, a half inch of Hg is about 500 feet or so. The question is, though, wouldn't you think there would be a way to capture a great deal more of the ram air effect and really boost the engine performance? Who wouldn't like to fly at 24 square at 12000 feet without a turbo charger? What makes me wonder about it is, even at 60 mph holding your hand out of the window of a car subjects it to a significant backward pressure, so the energy must be there. The energy is there but it's no bigger than what Mooney claims. Flat-plate drag at 100 knots is 29 pounds; dicide that by 144 square inches and get around 0.2 psi, or about 0.4" Hg. Not much. AT 200 knots it will be four times that, which still isn't a lot. In the 1970's Ford sold some cars with "Ram-Air Induction" systems. A scoop mounted on the carb that stuck out above the hood, to ram vast volumes of air into the carb and get way more horsepower. That's what they wanted you to believe. At 60 mph the pressure recovery would have been laughably tiny, but Ford's profits were impressive. That was the good old days! A jig saw and some sheet metal BLASTED your 427 cube inch engine to over 600 hp!!!, and at 400-500 mph, you'd be economizing on fuel to boot!. Ken |
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Ram air
On Jun 1, 8:06 pm, Gezellig wrote:
It happens that formulated : In the 1970's Ford sold some cars with "Ram-Air Induction" systems. A scoop mounted on the carb that stuck out above the hood, to ram vast volumes of air into the carb and get way more horsepower. That's what they wanted you to believe. At 60 mph the pressure recovery would have been laughably tiny, but Ford's profits were impressive. Had a Trans Am, scoop was reversed, facing the windshield, had a flap that opened when MP increased. They claimd that the reversed position was at the low pressure point at the base of the windshield hence enhancing the rammed air effect. I don't know, it was cool, the scoop assembly was attached to the engine so that on acceleration you could see the engine sitting down on its mounts as the scopp popped open and lowere ever so slightly. Locating the scoop at the low-pressure point wouldn't do much for ram-air effect, would it? I think the real idea would have been to make sure the driver heard that thing sucking loudly so it sounded like a real powerhouse I once converted a 14 foot outboard runabout to a 13 foot inboard Cracker Box with a Chev 283 straight-shaft setup. The exhausts were water-cooled and exited through the transom. Made so much noise that I made two mufflers and quieted it right down. The carb's flame arrestor stuck up far enough that I had a scoop on the deck, facing away from the cockpit (which was at the back). Everything else was covered. I dropped my Dad off on a gravel bar on a lake once, so he could fish off it while I ran to the far end of the lake to try the fishing there, three or four miles away. He told me he knew when I was coming back; he could hear that Rochester Quadrajet four-barrel open up and suck vast quantities of air; the boat got one mile per gallon at full throttle with that huge carb. But went real fast. I sold it years ago and I bet it don't go real fast no more, with fuel prices the way they are now. Dan |
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Ram air
On Jun 1, 7:59 pm, wrote:
On Jun 1, 8:06 pm, Gezellig wrote: It happens that formulated : In the 1970's Ford sold some cars with "Ram-Air Induction" systems. A scoop mounted on the carb that stuck out above the hood, to ram vast volumes of air into the carb and get way more horsepower. That's what they wanted you to believe. At 60 mph the pressure recovery would have been laughably tiny, but Ford's profits were impressive. Had a Trans Am, scoop was reversed, facing the windshield, had a flap that opened when MP increased. They claimd that the reversed position was at the low pressure point at the base of the windshield hence enhancing the rammed air effect. I don't know, it was cool, the scoop assembly was attached to the engine so that on acceleration you could see the engine sitting down on its mounts as the scopp popped open and lowere ever so slightly. Locating the scoop at the low-pressure point wouldn't do much for ram-air effect, would it? I think the real idea would have been to make sure the driver heard that thing sucking loudly so it sounded like a real powerhouse I once converted a 14 foot outboard runabout to a 13 foot inboard Cracker Box with a Chev 283 straight-shaft setup. The exhausts were water-cooled and exited through the transom. Made so much noise that I made two mufflers and quieted it right down. The carb's flame arrestor stuck up far enough that I had a scoop on the deck, facing away from the cockpit (which was at the back). Everything else was covered. I dropped my Dad off on a gravel bar on a lake once, so he could fish off it while I ran to the far end of the lake to try the fishing there, three or four miles away. He told me he knew when I was coming back; he could hear that Rochester Quadrajet four-barrel open up and suck vast quantities of air; the boat got one mile per gallon at full throttle with that huge carb. But went real fast. I sold it years ago and I bet it don't go real fast no more, with fuel prices the way they are now. Dan I confess to enjoying ancedotal stories. As a monster nut brat I got some tin cans together and built a pulse jet, complete with a flapping duct input, and used a hair dryer for my air input source, in my parents downstairs fireplace. So I pour in some gas into the thing, lite it up, turn on the hair dryer and holy poop, the duct starts fluttering and flames are fluttering out the ass end! It worked! It buzzed! I probably used a pint of gasoline per minute of operation, but that wasn't the point, it was actually seeing the damn thing in operation. Hands on is good stuff. Ken |
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Ram air
Ken S. Tucker explained on 6/2/2008 :
I confess to enjoying ancedotal stories. As a monster nut brat I got some tin cans together and built a pulse jet, complete with a flapping duct input, and used a hair dryer for my air input source, in my parents downstairs fireplace. So I pour in some gas into the thing, lite it up, turn on the hair dryer and holy poop, the duct starts fluttering and flames are fluttering out the ass end! It worked! It buzzed! I probably used a pint of gasoline per minute of operation, but that wasn't the point, it was actually seeing the damn thing in operation. Hands on is good stuff. Ken Proof there is a God, you survived yourself. |
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Ram air
"Ken S. Tucker" wrote in
: On Jun 1, 7:59 pm, wrote: On Jun 1, 8:06 pm, Gezellig wrote: It happens that formulated : In the 1970's Ford sold some cars with "Ram-Air Induction" systems. A scoop mounted on the carb that stuck out above the hood, to ram vast volumes of air into the carb and get way more horsepower. That's what they wanted you to believe. At 60 mph the pressure recovery would have been laughably tiny, but Ford's profits were impressive. Had a Trans Am, scoop was reversed, facing the windshield, had a flap that opened when MP increased. They claimd that the reversed position was at the low pressure point at the base of the windshield hence enhancing the rammed air effect. I don't know, it was cool, the scoop assembly was attached to the engine so that on acceleration you could see the engine sitting down on its mounts as the scopp popped open and lowere ever so slightly. Locating the scoop at the low-pressure point wouldn't do much for ram-air effect, would it? I think the real idea would have been to make sure the driver heard that thing sucking loudly so it sounded like a real powerhouse I once converted a 14 foot outboard runabout to a 13 foot inboard Cracker Box with a Chev 283 straight-shaft setup. The exhausts were water-cooled and exited through the transom. Made so much noise that I made two mufflers and quieted it right down. The carb's flame arrestor stuck up far enough that I had a scoop on the deck, facing away from the cockpit (which was at the back). Everything else was covered. I dropped my Dad off on a gravel bar on a lake once, so he could fish off it while I ran to the far end of the lake to try the fishing there, three or four miles away. He told me he knew when I was coming back; he could hear that Rochester Quadrajet four-barrel open up and suck vast quantities of air; the boat got one mile per gallon at full throttle with that huge carb. But went real fast. I sold it years ago and I bet it don't go real fast no more, with fuel prices the way they are now. Dan I confess to enjoying ancedotal stories. As a monster nut brat I got some tin cans together and built a pulse jet, complete with a flapping duct input, and used a hair dryer for my air input source, in my parents downstairs fireplace. So I pour in some gas into the thing, lite it up, turn on the hair dryer and holy poop, the duct starts fluttering and flames are fluttering out the ass end! It worked! It buzzed! I probably used a pint of gasoline per minute of operation, but that wasn't the point, it was actually seeing the damn thing in operation. Hands on is good stuff. Please do build another one just like that and put it on youtube, then.. I've only ever seen one person die right in front of my eyes before. Bertie |
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Ram air
wrote in message ... On Jun 1, 8:06 pm, Gezellig wrote: It happens that formulated : The biggest performance advantage to ram air was always recognized as COLD air, not increased pressure. That's why racers began using the base of the windshield for an intake, instead of forward a scoop. They could get plenty of cold air without increasing the frontal area of the vehicle. It's actually a HIGH pressure area, hence the reason so many vehicles have there fresh air intakes located there. |
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Ram air
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