how big does landing gear have to be?
 

Comparing an A-26 -

http://www.air-and-space.com/2007091...anding%20m.jpg

Or a Constellation -

http://www.militaryfactory.com/aircr...ellation_2.jpg

To, say, a 737 -

http://www.aerospaceweb.org/aircraft...37/b737_05.jpg

Why are the wheels of older aircraft so big for the size and weight of the aircraft?

Sixto
87 300D

http://palmettoscoop.com/wp-content/.../soulplane.jpg

And then you got dem rimz

I would imagine that it all depends on what you are going to be landing on.

Fresh, smooth tarmac.... little wheels, no problem, and less weight...

Old bumpy dirt strip... may want a little more rubber...

^^^^ Indeed a lot of the earlier stuff had to land on grass for example - but as planes got bigger and heavier they needed stronger runways to support the weight.

It's the the old concrete to rubber ratio again...

I suspect it has to do with needing the room for the props too.

Technology has changed since those days...so has the alloys and compounds used.

The big tires were for landing on unimproved or makeshift runways.

Because military aircraft are designed to be slammed down hard on short poorly made runways.

Commercial planes land on nice runways.

Navy planes have extremely strong gear for aircraft carrier landings.

I meant the wheels and tires more than strut beefiness and length. I was thinking of the load. Wouldn't a dirt or gravel runway have more give than a concrete runway? The A-26 looks to have flotation tires compared to the 737. I'd expect to see curb rash on the 737's wheels after a hard landing. A C-130 will land in places I'd hesitate to take a W461 and it doesn't have higher profile tires than the A-26 with respect to the landing load, granted only a small bit of the C-130 gear is exposed.

Sixto
87 300D

I think you are right, but for a different reason. The concrete is harder for sure. So on dirt runways, the tire is always trying to run up hill- out of the "give" you mentioned above.That puts more load on the strut than if on concrete.

Anyone agree that the supper constellation was one of the prettiest prop planes ever?

It has a certain charm - I'm still pretty nuts about virtually any prop boat plane though...

The bigger the wheel, the lower the rolling resistance (not the same as drag) but the greater the centripetal force that tries to pull the tyre off the rim. Modern aircraft have higher take-off and landing speeds than older, slower machines, necessitating wheels that can reach higher angular velocities - hence, smaller diameters. Not having to provide clearance for a prop helps as well.

To reduce contact pressure on the tyres, add more tyres:
http://cdn.stripersonline.com/9/91/9...ttach17967.jpg

Just one reason, maybe not the reason. It would also be cheaper to manufacture more smaller tyres than fewer larger ones.

BTW, hyia. New guy here.

Welcome aboard PC:).

That's for taking off / landing in mud / wet grass.

Not exactly prop driven and not exactly an airplane - Orlyonok - YouTube

Sixto
87 300D