Starlionblue From Hong Kong, joined Feb 2004, 15874 posts, RR: 66 Reply 2, posted (8 years 8 months 3 days 10 hours ago) and read 4063 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
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
G4doc2004 From United States of America, joined Feb 2004, 123 posts, RR: 0 Reply 3, posted (8 years 8 months 3 days 6 hours ago) and read 3988 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
BuyantUkhaa From Mongolia, joined May 2004, 2781 posts, RR: 3 Reply 4, posted (8 years 8 months 2 days 12 hours ago) and read 3811 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).
StudentFlyer From Australia, joined Sep 2004, 688 posts, RR: 4 Reply 7, posted (8 years 8 months 1 day 21 hours ago) and read 3611 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)...
Lehpron From United States of America, joined Jul 2001, 7028 posts, RR: 22 Reply 8, posted (8 years 8 months 1 day 20 hours ago) and read 3605 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.
IL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0 Reply 9, posted (8 years 8 months 15 hours ago) and read 3481 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.
Starlionblue From Hong Kong, joined Feb 2004, 15874 posts, RR: 66 Reply 11, posted (8 years 8 months 11 hours ago) and read 3435 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." - from Citadel by John Ringo
IL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0 Reply 12, posted (8 years 7 months 4 weeks 1 day 12 hours ago) and read 3312 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
Thrust From United States of America, joined Sep 2003, 2673 posts, RR: 11 Reply 13, posted (8 years 7 months 3 weeks 6 days 22 hours ago) and read 3152 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
IL76TD From United States of America, joined Jul 2004, 289 posts, RR: 0 Reply 14, posted (8 years 7 months 3 weeks 6 days 18 hours ago) and read 3134 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
Starlionblue From Hong Kong, joined Feb 2004, 15874 posts, RR: 66 Reply 15, posted (8 years 7 months 3 weeks 6 days 6 hours ago) and read 3085 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." - from Citadel by John Ringo
Lehpron From United States of America, joined Jul 2001, 7028 posts, RR: 22 Reply 16, posted (8 years 7 months 3 weeks 5 days ago) and read 2994 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.
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