Bailing out at high speeds

[Richie]

You can see why we can't do it.




http://www.youtube.com/watch?v=MgWWIDNzM78

[5./JG27.Farber]

Something not really moddeled in clod at the moment but was in IL2 1946. I hope to see the return of the delayed bail out or no bail out due to speed.

Is there a bug ticket for that?

[raaaid]

actually this is wrong:

according bernuoilli any fluid at high speed creates a vacuum that pulls you

the pitot tube to measure speed is based on that

[bongodriver]

actually this is wrong:

according bernuoilli any fluid at high speed creates a vacuum that pulls you

the pitot tube to measure speed is based on that


Actually you are wrong, fluids can create pressure as well as vacuum depending on the surface shape they are passing, dynamic pressure is what the pitot measures for airspeed, next time you are alowed out into the community and are in a car, put your head out the window and tell me if you feel a pressing force on your face or suction.

[ATAG_Snapper]

Actually you are wrong, fluids can create pressure as well as vacuum depending on the surface shape they are passing, dynamic pressure is what the pitot measures for airspeed, next time you are alowed out into the community and are in a car, put your head out the window and tell me if you feel a pressing force on your face or suction.

In a similar vein, the odd occasion I'M allowed out in the community I swear I've felt BOTH pressure and suction simultaneously. Riding the Hog on the Interstates/400-series highways (Canada) we occasionally see speeds of 80+ mph. Riding with no windshield and wearing half helmets, we obviously feel the wind pressure, but sometimes my buds and I have found it takes more effort to just draw in breath. It may be the wind pressure on our torsos, but the sensation is more like the wind is getting SUCKED out of our lungs. Could this be some sort of Venturi effect? Trust me, we all keep our mouths closed, especially in Junebug season, so there's no pressure equalization going on there.

When we ride with windshields attached, there's never been a problem.

[Sternjaeger II]

actually this is wrong:

according bernuoilli any fluid at high speed creates a vacuum that pulls you

the pitot tube to measure speed is based on that

what is wrong exactly? Apart for your presence here that is..

[raaaid]

thats not what bernouilli says

bernouillis eqaution clearly states v in its equation as an scalar not a vector

the irony is that your right and bernouillis wrong

but if we make true science... well petrol industry doesnt sponsor real science

what you call dinamic presure is not other thing but the reuslt of bernuillins equation with velocity of the fluid = 0(for example in the fornt of a submarine as well in the back) which creates a gradient since in the side pressures low for speed of the fluid being high

[SG1_Lud]

In a similar vein, the odd occasion I'M allowed out in the community I swear I've felt BOTH pressure and suction simultaneously.

After what I thought it was the starting of an interesting story, I was dissapointed lol

[ATAG_Snapper]

After what I thought it was the starting of an interesting story, I was dissapointed lol

Crikey, after reading your post I can't believe I phrased it the way I did. Too many distractions around me today is my only excuse! LOL

[raaaid]

actually with a wind pressure in your face it should be easier to breathe
:rolleyes:

[bongodriver]

actually with a wind pressure in your face it should be easier to breathe
:rolleyes:

Actually it is, the feeling of difficulty comes from the body's own reflex against the unnatural feeling of air being forced in, overcome that and you are getting ram air pressure straight into the lungs.

[ATAG_Snapper]

actually with a wind pressure in your face it should be easier to breathe
:rolleyes:

Yeah, you would think. But with no windshield there is also strong pressure on our chests, since our riding posture is upright, similar to that of a car

TBH, for the vast majority of riding which is usually well under 120 kmh on the highways and 80 kmh or so in the country, there is absolutely no difference whatsoever. Almost all my rides (154K km on the odometer of my current ride) are without windshield, wearing just the half helmet and prescription goggles (ie. no full face helmet or faceshield). Windblast is certainly there and is exhilarating, but no perceived difference in ease or difficulty in breathing. It's only been on rare occasion after doing a blast down the open highway when I've queried the guys during a gas stop, "Is it just me, or was it a bit hard to breathe those last few miles?". The answer has always been in the affirmative, so it wasn't just my imagination. There may possibly have been strong crosswinds, but can't say for sure.

[raaaid]

yeah i had two bikes i knew that i was "cooltrolling" take this other cool trol

a pitot tube has in one end v=0 and in other v= wind speed

from this theres a pressure gradient which creates a column of fluid

from the height of this fluid apllying bernuiili you know the speed

you know where the caught is and you should never tell in an exam

velocity=0 both if the tube is facing the wind or oposite to the wind

in other words presure in the mouth is identical if your going forward than if your going backwards

of course this is a lie but if this is difficult for you to digest you can call it a simplification with a more complex reality in whcih other factors play role :)

[ATAG_Snapper]

Actually it is, the feeling of difficulty comes from the body's own reflex against the unnatural feeling of air being forced in, overcome that and you are getting ram air pressure straight into the lungs.

Makes sense. If there's a reflex action occurring as you describe resisting the influx of air, perhaps the sensation to us was perceived as suction. It was never close to being any kind of danger -- far from it. Mildly uncomfortable over the duration of the ride is the best description.

[Kupsised]

Back to the video... :P

In the test seat (the one on rails), what is that sheet they're pulling over their faces to trigger the seat? Was that ever included in any production seats does anyone know?

It could be just for the test rig I suppose, to eliminate the need for hat and goggles, but it seems a bit of a weird way of doing things if that's what it is. Surely a hat would be more practical.

[bongodriver]

Back to the video... :P

In the test seat (the one on rails), what is that sheet they're pulling over their faces to trigger the seat? Was that ever included in any production seats does anyone know?

It could be just for the test rig I suppose, to eliminate the need for hat and goggles, but it seems a bit of a weird way of doing things if that's what it is. Surely a hat would be more practical.

Yes the sheet is present on any ejector seat with the overhead black and yellow handle, the idea behind it is to provide some protection to the face on egress, but overhed handles were shown to be difficult to reach in an aircraft which is seriously out of controll and inducing high 'g' loads to the pilot, I believe the overhead handles were present in aircraft like the F14 and F4 and as far as I know only Martin Baker seats had them.

[Kupsised]

Yes the sheet is present on any ejector seat with the overhead black and yellow handle, the idea behind it is to provide some protection to the face on egress, but overhed handles were shown to be difficult to reach in an aircraft which is seriously out of controll and inducing high 'g' loads to the pilot, I believe the overhead handles were present in aircraft like the F14 and F4 and as far as I know only Martin Baker seats had them.

So they were present on all the MB seats with the overhead handles? Even so, thanks for that. I guess you learn something new every day