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A380, Why Such A Small Nose Wheel?  
User currently offlineA380900 From France, joined Dec 2003, 1117 posts, RR: 1
Posted (10 years 2 months 2 days 21 hours ago) and read 5345 times:

How come the A380 has only two wheels in the front?

16 replies: All unread, jump to last
 
User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3702 posts, RR: 34
Reply 1, posted (10 years 2 months 2 days 13 hours ago) and read 5023 times:
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How would you steer a bogie in a sharp turn?

Most of an a/c's weight is designed to be around the C of G & C of L


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17118 posts, RR: 66
Reply 2, posted (10 years 2 months 2 days 12 hours ago) and read 5003 times:

Most of the weight is on the body and wing gear. Making the nose gear more complex brings with it a host of problems. As VC-10 says, how would you steer a bogie or a double set of nose wheels in a sharp turn. There would be lots of scrubbing.

I think you will also find those wheels aren't really small  Big grin



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineG4doc2004 From United States of America, joined Feb 2004, 123 posts, RR: 0
Reply 3, posted (10 years 2 months 2 days 8 hours ago) and read 4928 times:

As the size of the gear/bogie assembly increases, so does the weight of the assembly and the area required to store it in flight. Not to mention a larger actuator to push it in the well. And, as Starlionblue stated so eloquently, those wheels are bigger than they look!


"Failure to prepare is preparing to fail"--Benjamin Franklin
User currently offlineBuyantUkhaa From Mongolia, joined May 2004, 2907 posts, RR: 3
Reply 4, posted (10 years 2 months 1 day 15 hours ago) and read 4751 times:

It would be possible to avoid the scrubbing by putting four wheels on one axle. That would be terribly unpractical however, it would be too wide to fit, or would have to rotate 90 degrees, and as already mentioned it would be too heavy. So I guess the current solution is the most sensible one (just don't land with the nose gear first).


I scratch my head, therefore I am.
User currently offlineSovietjet From Bulgaria, joined Mar 2003, 2640 posts, RR: 17
Reply 5, posted (10 years 2 months 1 day 5 hours ago) and read 4596 times:
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It's possible to steer it. Just design it like an An-124. Never heard of them having problems steering.

User currently offlineAirbus Lover From Malaysia, joined Apr 2000, 3248 posts, RR: 9
Reply 6, posted (10 years 2 months 1 day 5 hours ago) and read 4593 times:

Why? Because they don't need it?  Nuts They find that the turning radius is acceptable and in line with airport facility compatibility.

I am not familiar with AN124 ops but could the AN124 require more turning circle than other a/c of similar size? Not sure, just guessing.


User currently offlineStudentFlyer From Australia, joined Sep 2004, 688 posts, RR: 3
Reply 7, posted (10 years 2 months 23 hours ago) and read 4551 times:

The AN124 and AN225 requires twin bogie at the nose probably because of the nose door of the aircraft -> maybe to withstand cargo loads during loading... The Airbus, well at least for the pax variant, does not have cargo doors. The F version is just a derivative of the pax version, so it would be impractical to give it 2 bogies, whereas the ANs are designed specifically for cargo ops, so it would just be viable to be fitted. That's my shot anyway.

And for turning, they shouldn't really have any effect, because both bogies turn simultaneously anyway... (but correct me if I'm wrong)...

Regards,
AK


User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 8, posted (10 years 2 months 23 hours ago) and read 4545 times:

>> "That would be terribly unpractical however, it would be too wide to fit, or would have to rotate 90 degrees, and as already mentioned it would be too heavy." <<

So the 4-wheel single-axile nose gear of a C-5a Galaxy probably wouldn't work despite the plane having existed since before the 747? I think it was ironic Boeing lost the contract that Lockheed won.

To answer the question, I donno, though I do have an earlier gif that clearly shows initial concepts of the A3XX with a 4 wheel nose gear like the Galaxy. I suppose there would be less load farther from the Center of Gravity.



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineIL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0
Reply 9, posted (10 years 1 month 4 weeks 1 day 17 hours ago) and read 4421 times:

The Russian cargo planes were designed with 4 wheel nose axles to decrease per wheel loads and increase the ability of the planes to operate from dirt, sand, or underdeveloped runways (with 4 wheels the nose loads better match the loads of the 16 rear tires on the IL76). No western plane has yet to match this ability to the extent of the ex mil russian freighters.

Our IL76's can turn on themselves (zero turning radius) so no, it does not affect that either.


User currently offlineTbanger From Australia, joined Jul 2004, 266 posts, RR: 0
Reply 10, posted (10 years 1 month 4 weeks 1 day 16 hours ago) and read 4398 times:

SMALL????????

There is a dude bending over in this photo and the top of the tyre comes up past his waist line


View Large View Medium
Click here for bigger photo!

Photo © French Frogs AirSlides



Champion, that wheel is huuuuuuuuge!  Nuts


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17118 posts, RR: 66
Reply 11, posted (10 years 1 month 4 weeks 1 day 13 hours ago) and read 4375 times:

The Russian cargo planes were designed with 4 wheel nose axles to decrease per wheel loads and increase the ability of the planes to operate from dirt, sand, or underdeveloped runways (with 4 wheels the nose loads better match the loads of the 16 rear tires on the IL76). No western plane has yet to match this ability to the extent of the ex mil russian freighters.

Our IL76's can turn on themselves (zero turning radius) so no, it does not affect that either.



True that no western plane can do this, but the A380 will not operate from dirt strips. And so the advantages of adding an extra two nosewheels on the flying slug would be eaten up by the extra complexity, weight and width of the nose gear well and mechanism.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineIL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0
Reply 12, posted (10 years 1 month 4 weeks 14 hours ago) and read 4252 times:

yea i wasn't saying that the A380 needed it, I was agreeing that it doesn't, and that the reason for additional nosewheels was not due to the planes static load on the mechanism, rather the ability to perform specialized operations requiring them

nosewheels generally have little load from the plane, planes are normally balanced evenly, which is why on many planes engine removal requires the nose to be tied down, assuming the weight of the engines was forward the center of gravity


User currently offlineThrust From United States of America, joined Sep 2003, 2690 posts, RR: 10
Reply 13, posted (10 years 1 month 3 weeks 6 days 1 hour ago) and read 4092 times:

The A380 in that photo looks so stubby from the front....it's hard to believe that the A380 is bigger than the 747  Wow!


Fly one thing; Fly it well
User currently offlineIL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0
Reply 14, posted (10 years 1 month 3 weeks 5 days 20 hours ago) and read 4074 times:

I agree, they do look stubby, i think they should have had a 747 style upper deck cockpit. The lower deck cockpit position makes the front look all droopy

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17118 posts, RR: 66
Reply 15, posted (10 years 1 month 3 weeks 5 days 8 hours ago) and read 4025 times:

I agree, they do look stubby, i think they should have had a 747 style upper deck cockpit. The lower deck cockpit position makes the front look all droopy


The 747 has the cockpit all the way up on the upper deck because they had to provide clearance for cargo, with or without a nose door. The 747 was meant to be a cargo plane as soon as the SSTs came into service in the late 70s. This never happened, but the cockpit remained up there.

The A380 has the cockpit in a position which has a couple of advantages over the 747:
- Aerodynamically I am not an expert, but I get the feeling the 747 has a pretty blunt nose and the 380 cleaves the air better.
- The cockpit area can be completely isolated from the rest of the aircraft, with it's own staircase from the entrance. On the 747 you have to walk through the upper deck. Security.
- More efficient layout of the double staircase to the upper deck.
- Less height above the ground for the pilots, enabling easier transition from 330/340.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 16, posted (10 years 1 month 3 weeks 4 days 2 hours ago) and read 3934 times:

>> "Aerodynamically I am not an expert, but I get the feeling the 747 has a pretty blunt nose and the 380 cleaves the air better." <<

Niether am i, but i heard that it had something to do with the cocpit bulge as a whole created more drag than as if it were smooth. The A380's nose now looks kind of like 7E7/787, just scaled up.



The meaning of life is curiosity; we were put on this planet to explore opportunities.
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