Something that many people not having a mechanical engineering back ground never seem to think much about when they're talking about "bigger airplanes" that can carry "bigger" loads, in other words, more weight. I'm sure any aeronautical engineer who would obviously be working for any aircraft manufacturer that is likely to be designing any cargo carrying A/C as big as, or even bigger than a C-5 (or an AN
-124) is already going to understand what I'm talking about............
Carrying a lot of weight is just one thing; the "shape" of the load is a whole different thing. I'm not an engineer, and I certainly don't design airplanes of any size, but I do happen to have a whole lot of experience when it comes to carrying "heavy loads".
Take a close look at all the big trucks going up and down any interstate highway; a very large % of them are pulling box-type trailers; for the past 15 years or so, almost all modern box-type freight trailers are 53 feet long. The whole reason being, that's as long as you can legally make them, and go anywhere in the U.S. on Interstate highways, without having a special permit. Anyone watching box type freight trucks on the highway has no idea at all what's inside of them.
I can tell you this without even opening up the doors...........all box trailers are used for hauling..........hundreds, even thousands of various sized BOXES ! ( with everything you can imagine, and a few things you may not imagine, in all of those boxes ! ) What you WON'T find being transported in any B-T freight trailer........are "things" that concentrate large amounts of weight into a relatively small area; "things" such as heavy machinery, bull dozers, steel in ANY of it's many forms prior to being made into finished products, etc etc etc.
Take a very close look at a big freight trailer next time you see one in a rest area on the interstate; you'll notice that they have NO frame under them at all ! Yet, you can load 40,000 lbs of "freight" in them, and they can carry it down the road; (sometimes.......but NOT always) many of them DO
break in two occasionally; but that's almost always because of improper loading, by inexperienced, (or down-right stupid) help at some freight dock.
What I'm pointing out here is.....big cargo carrying airplanes, just like freight trucks, MUST be designed to accomodate the types of loads they are going to carry; if you have something that weighs, say, 40,000 lbs, (such as a 40,000 lb coil of steel), there is NO possible way to carry it in a frameless box type trailer, even though that trailer hauls 40K loads on every trip; here's an example I'm VERY familiar with; on a 40 or 42 foot freight trailer, you can haul 40,000 lbs of Duncan Hines Cake Mix; it will be in 2,800 small cartons, and will be stacked evenly, 8 ft high, over the entire length of the trailer; You CAN
NOT however, haul, say, four milling machines, each weighing 10K; for several reasons; even if you loaded two 10K machines at the extreme nose, and the other two right over the rear tandem wheels, there is NO possible way to secure them properly, The EXACT same things must be taken into account when you design ANY cargo carrying A/C; Anything designed to carry,say, 40,000 to 50,000 pounds in just a few feet, MUST of necessity have a tremendously strong deck (or floor, same thing); the problem being, to gain strength, you must ADD
weight; every pound you add to make the deck stronger, makes the airplane heavier, requiring more power, meaning bigger engines, which burn more fuel, and jet fuel being quite heavy, needs bigger and bigger wing area to haul all this fuel.
There are many very knowledgeable engineers contributing this forum; I'm guessing that most if not all of them will agree with me that ANY big air lifter, ( such as the C-5 Galaxy, the C-17, or the AN
-124 ) , are themselves marvels of engineering; yes, you can always use newer, lighter, stronger materials to achieve slight improvements in performance;
(a great example being the new 787 ); And that's just a "mid level people carrier" ! Can you just see Boeing or AB
setting out to "bet the farm" trying to build something to carry more load, get there quicker, burn less fuel, than what we have right now ? It may not be impossible from an engineering standpoint, but I think it would require about three times the effort that went into the A 380 ! Yes, the A 380 and the B 747 are both used for hauling "cargo"; but that's a word that describes MANY things; you will never see for instance, an airplane hauling an object which concentrates as much load, in as little space, as a 50,000 lb coli of sheet steel; yet 50K coils are carried daily by 5 axle tractor trailer trucks weighing on average, 40,000 lbs. ( I should add, many loads of steel being hauled ARE indeed "overweight", and can and do cause very hefty fines when caught. (but that's another story)
Back to the C-5 Galaxy; I've never had the pleasure of flying in one, but I have been inside of quite a few of them, and I have spent quite a bit of time examining and studying the cargo ramps that extend out to the tarmac to allow such tremendous loads as an M-1 Abrams MBT
to be driven into the cargo bay of the A/C; someone mentioned that an M-i Abrams weighs like 129,000 lbs; so two of them would present a load of about 260,000 lbs. I forget the exact figures for the cargo bay of the C-5, but I can tell you from memory, it's pretty d*** long; a lot longer than two M-1A1's parked, ened to end, I'm guessing; but just getting them inside of the airplane is just the beginning; you have two VERY heavy objects, both of which "concentrate" something like 65 tons of weight, into a pretty small area; Just for the sake of illustration, I'm going to guess that 2 M1A1 tanks, parked touching each other, would use up, say, 2/3, or maybe even 3/4 of the cargo bay length;
I'm also going to assume that the people who designed the C-5 Galaxy had a pretty fair idea of what kinds of military hardware it was going to be called on to transport. Anything designed to haul things as heavy as a single or even two M-1A1 tanks is obviously going to need a VERY rigid and strong supporting deck, not only to support the weight, but to offer something strong enough to tie to, to keep all that weight from moving during flight;
I remember quite well the very first C-5 Galaxy I saw on the ground and got to walk through; I even had a chance to speak with the flight crew and ask a few dumb questions; this was probably within a year of when the C-5 first went into service, so it's "been awhile" now. I even remember what I asked the pilot; "when are you leaving to return to Georgia"? (because I'm going to be here to watch !) He seemed to like my question, and gave me a very specific answer; "8:45 AM
, tomorrow morning" ; my other question was........this gigantic cargo area is completely empty; so may I correctly assume you will have a very light fuel load ? This question got a huge grin on his face ! (which, as far as I can recall, is probably the first and possibly only time I've said anything to a "bird Colonel" that made him grin); He said to me........"not only is your assumption correct, I can ALSO tell you, when we climb out, a lot of people watching are going to think "this thing" is a great big fighter plane ! I was AT
Lunken Airport an hour before the C-5 departed (at exactly 8:45 AM
), and I doubt if many C-5's have ever made a more "impressive" take-off and climb out ! ( Somehow, I don't think you would be likely to see such impressive performance if the C-5 was carrying even one M-1A1 MBT
Taking all of this into consideration, even though I have no idea what the Generals running the USAF
are going to think what they need next in the way of air lift capability, I really can't see a whole lot of escalating "need" or "demand" for much greater airlift capability than exists right now; and taking into consideration that the development costs for anything even equalling the C-5's capability are certainly sure to be at least double, if not quadruple what the C-5's were, I'm guessing that the USAF
may even be obliged at some point to rely on Fed-Ex or UPS for the bulk of their airlift needs. ( Just remember...........everything requiring "funding" STARTS in the House of Representatives, which as everyone knows, is currently controlled by a bunch of "tight-###" Republicans who are actually concerned with "fiscal discipline".)
Stupidity: Doing the same thing over and over again and expecting a different result; Albert Einstein