C-5 upgrades a bit more clear for Robins visionaries (Links to photos)

Macon.com ^ | Wed, Nov. 16, 2005 | Gene Rector

[RayChuang88]

If I remember correctly, the first versions of the CF6-80 engines were rated around 50,000 lb. of thrust and was used on the 767-200/300 and some later A300B/A310 models.

The F103-GE-100 used on the E-4 and VC-25A are rated at around 53,000 lb. thrust, and I believe that's more or less the same engine that will be used on the C-5M. Gawd, it will be so strange to hear a C-5 fly over sounding more like a 747, given that you won't hear the very distinct loud whine of the old TF39 engines.

[Paleo Conservative]

Why not retrofit the C-5 with the F117 engine (P & W 2040) that the C-17 uses to reduce your spare parts inventory?

Probably because the TF-39 used on the C-5 was the ancestor of the CF6-80C2. The engines are similar enough to not require major redesigns of other subsystems on the C-5. They are also similar to the engines used on Airforce One and the E-4B's.

[taildragger]

Paleo, thanks, Happy T-Day.

I can't hide my bias towards P & W being a former employee. Your knowledge of GE engines makes me think you have some experience with them.

My then girlfriend (my wife of over 10 yrs now!) did C-17 Flight Test, great bird.

[Paleo Conservative]

Interesting -at one point the C-5 took 50 man hours of maintenance for every hour in the air. I have been told that the C-17 takes about 10. Does this retrofit remove a lot of the heavy maintenance items?

Most of the mechanical systems are being upgraded with off the shelf commercial technology. The APU's are also being replaced. All the aircraft have to first go through the AMP to upgrade the cockpit and avionics before getting the RERP. The cockpit upgrades especially will help improve maintainability due to commonality of the computers with the 777 and other commercial aircraft. Instead of having lots of obsolete mechanical gages manufactured by companies that no longer exist requiring the skills of a Swiss watch maker to repair, it will have several identical LCD screens that can easily replaced if one fails. Even if one screen fails in flight, the instrument displays can be moved to another screen. The whole idea is to use commercially available parts to cut down on costs and take advantage of technical advances available to the airlines.

Lockheed is guarantying a 75% mission capability rate, but some think the reliability might get as high as 85%. Effectively even with the retirement of 14 C-5A's it would be like having and additional 20 C-5's available. The increase in thrust will allow an increase in the maximum takeoff weight and effectively increasing the amount of lift available without increasing the number of planes.

http://www.globalsecurity.org/military/systems/aircraft/c-5-serv.htm

[mad_as_he$$]

Nice, thanks for the answer. Good point about supporting obsolete mechanical stuff with no vendor making new parts.

Years ago I worked with a retired Air Force Sargent that was a crew chief on some of the first C-5's. He claimed that when there was a fly off between Lockheed and Boeing that Boeing loaded a 747 up to the spec'ed weight (I think 150,000 pounds) with sandbags. It took most of the runway at Edwards to get off the ground and then did one lap around Edwards and landed. The story goes that the frame a bent and Boeing scrapped it in place. Good story but smells of urban legend.

[Dilbert56]

Off topic but related: Does anyone know if we're re-engining the B-52s? Supposedly 4 turbofans replace the 8 turbojets with all the benefits of modernization. Last thing I heard was the numbers flipped when you factored in the elimination of in-flight refuelings at $165K each.

[Jackknife]

Three C-5s - two "B" models and one "A" - are undergoing RERP at Lockheed's Marietta plant near Atlanta. One aircraft is 80 percent complete. Another is about 40 percent done. Work on the third aircraft, a C-5A, began in September.

I live about a five minute drive from the tarmac in Marietta, right in the flightline. Having lived in this area since I was born (40 years), I have grown up watching these beautiful giants fly over. I saw one of these 3 C-5's just a couple of days ago on a test flight. A few times, they have come right over the house so low that I could see the wings flexing!

What a bird!!

[VOA]

bump

[Paleo Conservative]

There have been proposals to reengine the B-52's either with four engines using Rolls Royce RB211 engines used on the 757 or eight Rolls Royce BR 715 engines used on the 717. The problem with 4 engines is the assymetrical thrust if one engine is lost. The rudder and vertical tailplane weren't designed for the loss of two of its eight engines on one side.

[yawningotter]

Very distinctive sound. You know when a C-5 is in the area long before you actually see it. And when you do see it, it looks like it is going so slow(especially on takeoff) that you wonder how it is staying in the air.

[taildragger]

Paleo,

Heck when I was back at Pratt ten years ago they were rumors floated of a re-engine then. PW 2000 I believe. This idea has been kicked around more than a ball at soccer practice.

The one I want to know about in terms of status is the B-1 upgrade that was proposed a while back.

All new avionics suite like the C-5 and the F-119 engines off the F-22 which would bring it back to supersonic and potentially super-cruise. If my memory is correct some B-1 drivers here on the Freep chimed in and they were absolutely drooling...

[hattend]

Back from Thanksgiving vacation BTTT