Hard Landings?

Rowdy · Post by **Rowdy** » Thu Apr 20, 2006 10:43 am

Found this on Google Video

http://video.google.com/videoplay?docid ... ng&pl=true

Yikes

fogghorn · Post by **fogghorn** » Thu Apr 20, 2006 10:44 am

Thats clip's about as bogus as the one of the water skiing harvards.

Springbok 2 · Post by **Springbok 2** » Thu Apr 20, 2006 7:04 pm

fogghorn wrote:Thats clip's about as bogus as the one of the water skiing harvards.

Shit Fogghorn, you still on about the harvard thing being bogus. I saw that show with my own eyes. Trust me when I say there is nothing false about the airshow boys doing their thing.

xsbank · Post by **xsbank** » Thu Apr 20, 2006 7:13 pm

Just look up the formula for hydroplaning - it doesn't mention how deep the water is. My friends who have done it claim you have to push the stick quite hard otherwise the water rejects you, and keep the power on!

That video is an old one, and its not a Boeing. Somebody's first attempt at a side-stick?

Siddley Hawker · Post by **Siddley Hawker** » Thu Apr 20, 2006 7:19 pm

All the female pax were probably wearing fur collars after that one.

TG · Post by TG » Fri Apr 21, 2006 6:47 am

It's a commercial done for a beer..... "Computerised" landing....

fogghorn · Post by **fogghorn** » Fri Apr 21, 2006 10:14 am

xsbank wrote:Just look up the formula for hydroplaning - it doesn't mention how deep the water is. My friends who have done it claim you have to push the stick quite hard otherwise the water rejects you, and keep the power on!

That video is an old one, and its not a Boeing. Somebody's first attempt at a side-stick?

Exactly, and hydroplaning requires a runway or other surface inches below the water surface to work because it provide the obvious cushion effect. Try hydroplaning anything on wheels on open water, it does not work. If it did work, amphib aircraft that landed wheels down on water would simply have a normal landing rather than a violent upset. The drag coefficient for a solid object contacting water (like a pressurized chunk of rubber) increases exponentially with speed.

w squared · Post by **w squared** » Fri Apr 21, 2006 10:33 am

Hmmmm....

Hydroplaning doesn't work without something solid under the water?

Perhaps you'd like to explain water skiing then?

Or the boat pulling that water skiier getting up on step?

Maybe you could explain how a snowmobile can hydroplane across stretches of open water?

Go take a physics class, Foghorn. Yer talking outta yer arse. Again.

Dust Devil · Post by **Dust Devil** » Fri Apr 21, 2006 11:58 am

w squared wrote:Hmmmm....

Hydroplaning doesn't work without something solid under the water?

Perhaps you'd like to explain water skiing then?

Or the boat pulling that water skiier getting up on step?

Maybe you could explain how a snowmobile can hydroplane across stretches of open water?

Go take a physics class, Foghorn. Yer talking outta yer arse. Again.

Staments like this tend to make me think your a pretty smart dude. But then I realize your workin in the patch and I realize I was wrong

Apologies in advance

w squared · Post by **w squared** » Fri Apr 21, 2006 12:09 pm

Dude, I'm in the patch...I never claimed to actually DO any work. After all, I am a safety hand.

xsbank · Post by **xsbank** » Fri Apr 21, 2006 1:09 pm

Fogghorn, go directly to the bar and don't talk to anyone - you are not safe to be out on the streets.

Hedley · Post by **Hedley** » Fri Apr 21, 2006 1:19 pm

Here's some foghorn math, where we prove that 2 equals zero:

a = 1
b = 1

a = b
a^2 = b^2
a^2 - b^2 = 0
(a-b)(a+b) = 0
(a-b)(a+b)/(a-b) = 0/(a-b)
1(a+b) = 0
(a+b) = 0
1 + 1 = 0
2 = 0

Clodhopper · Post by **Clodhopper** » Fri Apr 21, 2006 4:21 pm

You have to see the full version of the video, where the announcer for the commercial comes on at the end. I can't remember if its for Heineken or some other beer, but its basically a joke that its the National Airline of some country "welcoming" a competing rugby team to its country to play its national team....

And its horribly fake. I can't even count how many times I've had friends send me this via email or PM, going "oh my god....this is scaaaaary".

Just look, I've never seen an A320 with Tundra tires before...and if you slam the nose down that hard, you bend the fuselage. Ask Skyservice.

ScudRunner · Post by **ScudRunner** » Fri Apr 21, 2006 7:40 pm

Fogghorn Old buddy, please Consult my Graphic for proper use of your Helmet Dont leave the house again without it!!!

CAPGEN · Post by **CAPGEN** » Fri Apr 21, 2006 8:21 pm

"The plaque for the alternates is in the ladies room..."

http://www.yourdailymedia.com/media/114 ... s_on_Water

fogghorn · Post by **fogghorn** » Fri Apr 21, 2006 8:53 pm

Wow, dissenting opinions just dont wash around here, do they! I said that video that started this thread was bogus. I also believe the water skiing harvards are, like the guy from Missouri says "SHOW ME". I will believe it when I see it up close and personal. Maybe one of you rocket scientists could expain why amphib aircraft that contact water with wheels down, flip - immediately.

Dog · Post by **Dog** » Fri Apr 21, 2006 9:37 pm

Sure: The rate of descent is too high and the main wheels of a amphib cause a rapid pitch down of the airplane (bad).
Where do you live? Come with me and we'll "wash the wheels".

fogghorn · Post by **fogghorn** » Fri Apr 21, 2006 9:54 pm

Well, whatever. I think a few people need to understand that hydroplaning occurs when a cover of water up to a couple of cm deep is supported by a firm surface, like a runway. Alot of amphib's have flipped, landing on glassy water with wheels down, the same circumstance as the Harvards which would be contacting the surface at a very low rate of descent. Maybe one of the rocket scientists could tell me at what rate of descent the contact would cause an upset, because their must be a critical number here vs. speed, tire pressure, contact area etc, etc, blah, blah, when landing on deep water. Maybe the water surface for the harvards is supported by a road or something and is 4 inches deep, now that would make sense.

Dog · Post by **Dog** » Fri Apr 21, 2006 10:04 pm

Nope, nothing under the water but more water. You go fast, step on the brakes and catch the pitch-down when you make contact. It's required training for anyone with over 500hrs in a Super Cub.

Clodhopper · Post by **Clodhopper** » Fri Apr 21, 2006 10:10 pm

CAPGEN wrote:"The plaque for the alternates is in the ladies room..."

http://www.yourdailymedia.com/media/114 ... s_on_Water

Fogghorn - watch the video in the above link...if you still think that is fake, then I can't help you any further.

fogghorn · Post by **fogghorn** » Fri Apr 21, 2006 10:11 pm

Yeah, I suppose standing on the brakes would create more water build up ahead of the tire and promote planing, or then again - would it compound the drag and flip that sucker over faster than you could say spit! Given the height that tail is in the air, the prop should be very close to hitting the water, why is there no spray around or immediately behind the prop?

Big Pratt · Post by **Big Pratt** » Fri Apr 21, 2006 10:29 pm

Foghorn,

Has it occured to you that maybe the mains on a Super Cub/Harvard (pick any tail dragger) are in front of the CG while the mains on an amphib are behind the CG?

Clodhopper · Post by **Clodhopper** » Fri Apr 21, 2006 10:34 pm

Big Pratt wrote:Has it occured to you that maybe the mains on a Super Cub/Harvard (pick any tail dragger) are in front of the CG while the mains on an amphib are behind the CG?

Regardless, the moment caused by the force of drag would result in a nose-down tendency. The wheels are below the C of G.

dog wrote:You go fast, step on the brakes and catch the pitch-down when you make contact.

xsbank · Post by **xsbank** » Fri Apr 21, 2006 10:40 pm

Hydroplaning speed = 10.35 x square root of the tire inflation pressure. Some use 9X.

That's all folks.

Ever seen a water skier ski on bare feet? If he slows down, amphibian!

BTD · Post by **BTD** » Sat Apr 22, 2006 6:13 am

Its just like barefoot waterskiing.

When Barefooting you keep your feet out infront of you to prevent from fliping over. You use your muscles and shift your weight to compansate. You could do this with power and the elevators in an aircraft.

If you move your feet aft you will be eating water before you can blink. Much like your amphib. I have never seen it done in a tricycle gear aircraft but I have heard of it.

Also remember generally when those amphibs come down on to the water with their gear hanging out, the pilots often don't know about it.