Usaf C-5 Galaxy Visits Canberra

[Todd M]

Photos from yesterdays visit of a C-5 Galaxy, a USAF freighter from Travis Air Force Base. The aircraft unloaded cargo, taxied to the runway, and then made its way very slowly back to the Fairbairn side of the airport with an unknown issue (Mechanical, forgot dinner, something like that).

 

 

 

 

 

[red750]

No doubt delivering the secret service equipment and presidential vehicles for President Obama's visit. Great line on TV last night - All the way with B.O. doesn't have the same ring as All the way with LBJ.

 

Peter.

 

 

[dazza 38]

I had a look inside a C 5 at Amberley.There is a ladder inside, that you climb up inside the Fin.Its to access the Horizontal Stab.Also when in the cockpit, its a long way down to the ground.:)

 

 

[Ignition]

Geez, do they normally have that much negative dihedral on the wings?

 

 

[dazza 38]

Geez, do they normally have that much negative dihedral on the wings?

Thats a new (Negative dihedral)lI think you mean Anhedral.Hey hey. Yes that is normal.Other examples are the F104 Starfighter,C17 Globemaster

 

 

[willedoo]

Thats a new (Negative dihedral)lI think you mean Anhedral.Hey hey. Yes that is normal.Other examples are the F104 Starfighter,C17 Globemaster

Seems to be a term getting around a bit now days, Dazza, but I'm like you, always known it as anhedral.

Cheers, Willie.

 

 

[willedoo]

Geez, do they normally have that much negative dihedral on the wings?

As Dazza said, it's normal, especially for transports, which mostly have shoulder mounted wings & low centre of mass. They're all generally fitted with yaw dampers, but looking at the front view of the C-5, it appears to have a very low centre of gravity with that profile, so that would probably require a coulple or 3 degrees more anhedral than some other transports. The anhedral is to increase the roll resistance & decrease the roll restoration force, so as to avoid roll-coupling or a Dutch Roll. Quite common with high mounted, swept back wings. Like the An-124 & others, they're wider & fatter on the bottom to accommodate loads; this lowers the centre of mass more than a more standard fusilage profile & correspondently increases the need for more downward slope on the wings. If the C-5 had straight wings, it would roll & restore too easily, at the same time losing directional stability & result in a Dutch Roll ( roll-coupling & roll convergence are other terms for it), excessive yaw & roll combined. Hope this helps.

Cheers, Willie

 

 

[Old Koreelah]

My 1960's Flight book said the C5 has 28 main wheels and, to reduce drag, the tyres are deflated before retraction.

 

A Presidential visit needs months of planning and costs mobs.

 

 

[Todd M]

No doubt delivering the secret service equipment and presidential vehicles for President Obama's visit. Great line on TV last night - All the way with B.O. doesn't have the same ring as All the way with LBJ.Peter.

Was delivering the many vehicles for the motorcade. A C17 was in a few days before it to deliver a chopper.

 

 

[Guest ozzie]

The services station attendant seemed happy with the motorcade filling up there. wonder if they used AmEx?

 

 

[siznaudin]

My 1960's Flight book said ... to reduce drag, the tyres are deflated before retraction.

Sorry, but I don't follow: could you explain how deflation of the tyres reduces drag, please?

 

 

[Old Koreelah]

Sorry, but I don't follow: could you explain how deflation of the tyres reduces drag, please?

Sorry, Siz, I was trying to be brief: the idea is that so many wheels take up an enormous space when retracted, requiring a huge bulge in the lower fuselage. By deflating the tyres before retraction, they can be squeezed into a much smaller space. Quite a few aircraft can adjust tyre pressure in-flight, eg. to suit different airfields.

 

(On a totally different tack, many would-be stowaways don't realise how compact the retracted undercarriage system is and have been crushed or frozen to death in flight.)

 

Lyle

 

 

[siznaudin]

Take a look at this web page http://www.airforce-technology.com/projects/c5/ ... but here's the significant extract from it if you want to save a bit of time. Nothing to do with reduction of the gear housing cross-sectional area, I think you'll find... your interpretation would require the tyres (sorry - tires) to be deflated before being retracted after each takeoff.. a bit of a pain in the posterior I would suggest.

 

"... The Goodrich tyres can be deflated in flight to suit the landing conditions at the destination airfield."

 

 

[siznaudin]

Geez, do they normally have that much negative dihedral on the wings?

They can have as much or as little, I guess - or as little or as much (anhedral, that is...)