Perplexing Propeller Question
Oct 18, 2013 17:52:47 #
Vapour trail for sure but what is that trailing from what I presume is a tie down cleat under the tail? Surely the pilot didn't leave a rope trailing behind as he flew...
Oct 18, 2013 17:55:22 #
jerryc41 wrote:
Was this strictly a camera thing, or was that visible to the naked eye?
If you want to see something weird, look at what happens when you take a picture of a spinning propeller with an iPhone.
http://www.google.com/search?q=propellers+photographed+with+an+iphone&espv=210&es_sm=122&tbm=isch&tbo=u&source=univ&sa=X&ei=HaxhUv3KCvLA4AOSioHQBA&ved=0CC4QsAQ&biw=1680&bih=892
If you want to see something weird, look at what happens when you take a picture of a spinning propeller with an iPhone.
http://www.google.com/search?q=propellers+photographed+with+an+iphone&espv=210&es_sm=122&tbm=isch&tbo=u&source=univ&sa=X&ei=HaxhUv3KCvLA4AOSioHQBA&ved=0CC4QsAQ&biw=1680&bih=892
he is getting spray on windshield.
Oct 18, 2013 17:56:00 #
Verd wrote:
Vapour trail for sure but what is that trailing from what I presume is a tie down cleat under the tail? Surely the pilot didn't leave a rope trailing behind as he flew...
With a long rope and a short trip, he can always find his way back. :D
EDIT: Vapor trail --
http://answers.yahoo.com/question/index?qid=20081124052533AAMKyRF
Oct 18, 2013 18:40:38 #
Jerry, MT Shooter gave a good explaination for this.
Yaro wrote:
Vapor trail makes sense. But I don't remember the vapor trail being visible to the eye. Is that possible?
Its visible, but because it dissipates in a fraction of a second it is seldom noticed by the naked eye and your eye cannot resolve the scene fast enough to see more than just a misty wash with no swirls. You shutter speed was quite fast and froze the prop as well as the vapor trails. I have seen this before with seaplanes in Alaska and Washington, but it takes almost 100% humidity and a very fast shutter to capture it, very hard to do intentionally.
Yaro wrote:
Vapor trail makes sense. But I don't remember the vapor trail being visible to the eye. Is that possible?
Its visible, but because it dissipates in a fraction of a second it is seldom noticed by the naked eye and your eye cannot resolve the scene fast enough to see more than just a misty wash with no swirls. You shutter speed was quite fast and froze the prop as well as the vapor trails. I have seen this before with seaplanes in Alaska and Washington, but it takes almost 100% humidity and a very fast shutter to capture it, very hard to do intentionally.
Oct 18, 2013 18:43:27 #
For some reason, all the planes left their ropes dangling. As a boater, I would never do that. Different rules must apply to planes.
Oct 18, 2013 18:50:52 #
that is a
1992 CESSNA 208
(10 seater)
with a
HONEYWELL TPE331-12JR
Horsepower: 1000 (Turbo-prop)
tips of those blades at full power is going at about Mach 2 or 3 thats about how fast the water is moving.
1992 CESSNA 208
(10 seater)
with a
HONEYWELL TPE331-12JR
Horsepower: 1000 (Turbo-prop)
tips of those blades at full power is going at about Mach 2 or 3 thats about how fast the water is moving.
Oct 18, 2013 18:56:11 #
Yaro wrote:
Hi Folks,
I was fishing in Alaska two months ago and took this picture of one of the fly-in planes taking off. I am puzzled why the propeller shows a trail of about 15 feet while the plane does not. Does anyone know what caused this? The shot was taken at 1/250 of a second. I like the way it looks but want to understand what caused this effect.
I was fishing in Alaska two months ago and took this picture of one of the fly-in planes taking off. I am puzzled why the propeller shows a trail of about 15 feet while the plane does not. Does anyone know what caused this? The shot was taken at 1/250 of a second. I like the way it looks but want to understand what caused this effect.
8-) 8-) 8-) "Con"densation trails from the prop tips and the elevator. Moisture in the air is compressed from gas to liquid and then back to gas. This photo is incredibly unique, and very uncommon. It could be a valuable teaching tool. Great shot!!! :thumbup: :thumbup: :thumbup:
Oct 18, 2013 20:13:54 #
davidrb wrote:
8-) 8-) 8-) "Con"densation trails from the prop tips and the elevator. Moisture in the air is compressed from gas to liquid and then back to gas. This photo is incredibly unique, and very uncommon. It could be a valuable teaching tool. Great shot!!! :thumbup: :thumbup: :thumbup:
Nope. The front of the prop is curved exactly like a wing. It is indeed an airfoil. As the prop spins, low pressure is created - that is what pulls the airframe forward. The rapid drop in pressure means the air expands - NOT compressed - and when air expands, temperature drops. If temperature and dew point are close, there is some rapid condensation which dissipates quickly.
It is expansion, not compression. Compression of gas does not turn it to a liquid - it changes it to a high pressure gas. The compression heats the gas.
Oct 18, 2013 20:29:47 #
Oct 18, 2013 22:43:23 #
106" prop at 1900 rpm is about 600 mph tip speed.
Well under Mach 1.
I don't know of any modern planes
whos' prop tips exceed Mach 1.
A few WWII era planes did, such as the Stearman and T-6 Texan.
Captain nailed it. :thumbup:
Well under Mach 1.
I don't know of any modern planes
whos' prop tips exceed Mach 1.
A few WWII era planes did, such as the Stearman and T-6 Texan.
Captain nailed it. :thumbup:
dirtpusher wrote:
that is a
1992 CESSNA 208
(10 seater)
with a
HONEYWELL TPE331-12JR
Horsepower: 1000 (Turbo-prop)
tips of those blades at full power is going at about Mach 2 or 3 thats about how fast the water is moving.
1992 CESSNA 208
(10 seater)
with a
HONEYWELL TPE331-12JR
Horsepower: 1000 (Turbo-prop)
tips of those blades at full power is going at about Mach 2 or 3 thats about how fast the water is moving.
Oct 18, 2013 23:06:34 #
Bpace wrote:
106" prop at 1900 rpm is about 600 mph tip speed.
Well under Mach 1.
I don't know of any modern planes
whos' prop tips exceed Mach 1.
A few WWII era planes did, such as the Stearman and T-6 Texan.
Captain nailed it. :thumbup:
Well under Mach 1.
I don't know of any modern planes
whos' prop tips exceed Mach 1.
A few WWII era planes did, such as the Stearman and T-6 Texan.
Captain nailed it. :thumbup:
try figurin it comes with a 3-bladed Hartzell brass edged. at
2700 RPM, Wipline 3450
whipline is... a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on the crank throws at high engine rpm, 38 to 42 in. off that line almost doubles.
Oct 18, 2013 23:32:31 #
The specs I found for that engine show 1591 shaft rpm.
A supersonic prop is extremely loud and inefficient.
Yaro, was that plane super loud as it passed by?
A supersonic prop is extremely loud and inefficient.
Yaro, was that plane super loud as it passed by?
dirtpusher wrote:
try figurin it comes with a 3-bladed Hartzell brass edged. at
2700 RPM, Wipline 3450
whipline is... a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on the crank throws at high engine rpm, 38 to 42 in. off that line almost doubles.
2700 RPM, Wipline 3450
whipline is... a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on the crank throws at high engine rpm, 38 to 42 in. off that line almost doubles.
Oct 18, 2013 23:37:02 #
Turboprops don't have a crankshaft.
I also fail to see what that would have to do with prop tip speed?
I also fail to see what that would have to do with prop tip speed?
dirtpusher wrote:
whipline is... a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on the crank throws at high engine rpm, 38 to 42 in. off that line almost doubles.
whipline is... a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on the crank throws at high engine rpm, 38 to 42 in. off that line almost doubles.
Oct 18, 2013 23:40:01 #
Bpace wrote:
The specs I found for that engine show 1591 shaft rpm.
A supersonic prop is extremely loud and inefficient.
Yaro, was that plane super loud as it passed by?
A supersonic prop is extremely loud and inefficient.
Yaro, was that plane super loud as it passed by?
loud and inefficient is correct. inefficient except on take off. xactly why get such sounds on take off.
are looking at tubo spec's? better look again.
Oct 18, 2013 23:45:16 #
Well, I wouldn't say super loud, but in a remote area of Alaska, any noise is loud so I'd have to say no.
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