# A question concerning aerial refuelling.



## Nonskimmer (Mar 10, 2005)

I've often wondered, and have never really found a satisfactory answer, as to why the US Air Force uses the exact opposite refuelling probe arrangement on it's aircraft from the Navy and Marine Corps.

The Air Force has the probe on the tanker, with the receiving aircraft having the "female" connection. The Navy/Marine tankers release a drogue to the probe on the receiving aircraft.

Is there an actual reason for this difference, or does the Air Force just like being difficult? 
I'm just curious.


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## Nonskimmer (Mar 12, 2005)

Answer me!!


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## Maestro (Mar 12, 2005)

I think you asked a question about a mystery of life... no one got an answer !


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## evangilder (Mar 14, 2005)

I wondered about that myself years ago, especially after Operation El Dorado Canyon, of which I took part. It was a joint AF/Navy operation that required each to provide their own tankers. I will have to see if I can find out if anyone at the museum knows any "gas passers". It is indeed a mystery...


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## the lancaster kicks ass (Mar 14, 2005)

sounds very interesting.........


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## DerAdlerIstGelandet (Mar 18, 2005)

To be honest I really dont know, but I would say it is because in tradition the US military can not agree on anything whether it is uniforms, equipment or aireal refueling.

The best guess that I can come up with is this. The Airforce uses large tankers such as the KC-135 which can carry more fuel in it because the fuel is carried in the fuselage. For this reason it uses a rigid fueling boom. It is easier to attach a rigid fueling boom to an aircraft if the boom has the male part and the aircraft has the female part. The KC-135 can not land on a carrier adn the Navy and Marine Corps needs refuelers that can take off from there carrier. The aircraft are too small to carry the fuel in the fusalage so most of the time the fuel is carried in external tanks. You can not attach a rigid boom to an external tank. It is therefore that a flexible hose is extended with a female part and the aircraft with the male part "penetrates" the hose. Like my terminology there!  
In all actuallity though all Airforce tankers are equipped with a flexible hose that has the female attachement so that Navy and Marine aircraft can refuel from it also.


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## Nonskimmer (Mar 18, 2005)

So then, the original question still stands.


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## MikeMan (Mar 19, 2005)

It probably has to do with fuel flow rates.

The airforce needs to be able to re-fuel Bomber/Transport/VIP planes with large offloads that would take forever through a hose a drouge but the higher flow of a boom makes it easier.


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## DerAdlerIstGelandet (Mar 19, 2005)

I talked to some people that used to fly for the navy and they did say that it was not the only reason but one of the reasons was the fact that none of the naval carrier refuelers could operate a boom because the aircraft were too small. They did not know the actual main reason though, and they did confirm that they did refuel from Airforce tankers also.


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## the lancaster kicks ass (Mar 20, 2005)

so i think it's solved then........


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## Nonskimmer (Mar 20, 2005)

Hmmm, that could be.


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## DerAdlerIstGelandet (Mar 20, 2005)

Well Ill be damned!


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## FLYBOYJ (Apr 9, 2005)

The refueling boom is actually a "spec" part and only certain companies can legally produce it. There was also an attempt to put a Boeing Boom on an Airbus by BAE, but Boeing quickly protested when they learned of this plan. It is true that the drogue system takes up the least amount of space. BAE Flight Systems of Mojave CA produced a "Bolt On" Drogue system made to go on 707s - *Instant Tanker!* 

Go to http://www.sargentfletcher.com/ars.htm and you could read about the company that makes these units


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## Nonskimmer (Apr 9, 2005)

Interesting. Thanks.


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## DerAdlerIstGelandet (Apr 10, 2005)

Yeap good stuff.


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## FLYBOYJ (Apr 11, 2005)

The company currently operating this aircraft is called Omega - here's their web site.

This mod was a nightnare to do - almost a year behind schedule!

Check out thier website http://www.fuelbirds.com/


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## DerAdlerIstGelandet (Apr 14, 2005)

I can believe it was.


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## FLYBOYJ (Apr 14, 2005)

What was funny was many of the engineers who designed the system didn't have a clue how to modify the airpane so the system could be installed


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## DerAdlerIstGelandet (Apr 15, 2005)

That almost sounds like the mechanics who work on our aircraft.


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## FLYBOYJ (Apr 15, 2005)

What type of aircraft?


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## DerAdlerIstGelandet (Apr 16, 2005)

UH-60L Blackhawks. A lot of our mechanics seem to think they know a lot more then they do or they just outright have no clue and then we end up doing a lot of the work ourselves then.


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## FLYBOYJ (Apr 16, 2005)

I know what you mean, I worked with many folks out of the military and I would say there was about a 50-50 mix. Some really knew their stuff, others didn't have a clue, especially when you put them around small recips (Cessnas, Pipers). Others were just butchers. I hate to say it but the worse maintainers I've seen out of the US Military were Marines!

I worked on air ambulance A-Star helicopters. My employer at the time made dammed sure I knew what I was doing before they turned me loose!

PS - Nice Photo!


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## DerAdlerIstGelandet (Apr 17, 2005)

FLYBOYJ said:


> I worked on air ambulance A-Star helicopters. My employer at the time made dammed sure I knew what I was doing before they turned me loose!
> 
> PS - Nice Photo!



That is what I want to do if I dont go back to school when I get out of the Army. Work for a German air ambulance or mountain rescue and then eventually move to Alaska and work there doing the same thing.


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## FLYBOYJ (Apr 17, 2005)

As a maintainer its very rewarding but strenuous, there's a lot of pressure on you. You also have to deal with the personalities of the flight crews. Many of my pilots were former Army, a couple of them would bark at me like I was on KP - after a few "discussions" they knew not to leave their helmet bag unattended while I was around  

Overall, its a job I liked but I was glad to move on - you really have to be into the mission if you want to stick with it!


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## DerAdlerIstGelandet (Apr 18, 2005)

FLYBOYJ said:


> As a maintainer its very rewarding but strenuous, there's a lot of pressure on you. You also have to deal with the personalities of the flight crews. Many of my pilots were former Army, a couple of them would bark at me like I was on KP - after a few "discussions" they knew not to leave their helmet bag unattended while I was around
> 
> Overall, its a job I liked but I was glad to move on - you really have to be into the mission if you want to stick with it!



I have been crewing and maintaining for almost 6 years now. I have 1256 flight hours logged in the Blackhawk now and several thousand hours of maintenance time. I really enjoy the job and cant wait to do it on the civilian side.


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## FLYBOYJ (Apr 18, 2005)

Well that's great, I wish you the best - do you have your A&P?


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## DerAdlerIstGelandet (Apr 19, 2005)

Yeah I just finished that actually. The hard part was actually finding someplace in Germany to take the test. The German A&P is actually different then the American one and I wanted the German. There happens to be 3 here in Germany that can give you the practical test.


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## FLYBOYJ (Apr 19, 2005)

Good show! - without an A&P you're sunk. I tell this to everyone getting out of the military who wants to continue in aviation as a maintainer. I'm guessing in Germany, you're getting the JAA Aircraft Maintenance Engineer Certificate, another great notch as that makes you marketable internationally. An A&P is worth at least a 2 year degree!


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## DerAdlerIstGelandet (Apr 19, 2005)

FLYBOYJ said:


> Good show! - without an A&P you're sunk. I tell this to everyone getting out of the military who wants to continue in aviation as a maintainer. I'm guessing in Germany, you're getting the JAA Aircraft Maintenance Engineer Certificate, another great notch as that makes you marketable internationally. An A&P is worth at least a 2 year degree!



There is actually a program with the US Army where I can take my military aviation training and my A&P and use it towards an Aviation Degree.


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## FLYBOYJ (Apr 19, 2005)

Great show - when you're ready to leave the military I could set you up with my former employer!


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## DerAdlerIstGelandet (Apr 20, 2005)

Are they in Alaska? If so hook me up. Ive got 15 months left.


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## FLYBOYJ (Apr 20, 2005)

Yep- Keep checking in at the website for AIR METHODS and PHI Helicopters (a google search should direct you to the exact site). They normally show what openings are available. When you start getting real short I'll try to get you an audience with the Air Methods HR manager (we'll talk more about that via e mail). I know they were looking for folks in Alaska a few years ago, right know from what I understand the hot spot is the US South east.


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## DerAdlerIstGelandet (Apr 21, 2005)

Thanks alot will check it out. PHI helicopters espially. I love rotary wing the best.


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## Medvedya (Apr 21, 2005)

Gawd, and to think you were picking sand and grit out of your food barely three months ago!


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## DerAdlerIstGelandet (Apr 21, 2005)

I still love working on them.


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## Medvedya (Apr 21, 2005)

And now you get to do the job you love in somewhat safer and more comfortable conditions! And I'm guessing the pay won't be peanuts either! 

Good stuff!


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## FLYBOYJ (Apr 21, 2005)

Hopefully we'll get you in! I always like helping Vets get work once they're out!


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## DerAdlerIstGelandet (Apr 22, 2005)

I appreciate any help.


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## FLYBOYJ (Apr 22, 2005)

hey - you the man!


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## DerAdlerIstGelandet (Apr 24, 2005)

Why yes I am! Naw just kidding.


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## Nonskimmer (Apr 24, 2005)

You're _not_ a man?


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## DerAdlerIstGelandet (Apr 24, 2005)

Last time I checked I was!


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## the lancaster kicks ass (Apr 24, 2005)

yes but anything could have happened between then and now, i suggest regular check ups........


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## DerAdlerIstGelandet (Apr 25, 2005)

I check myself atleast 3 times a day. Well atlest I get a hands on exam from my wifey assistant one of those times!


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## HealzDevo (May 25, 2005)

As I said I think the Boom method is something to do with fuel flow rates. Fuel is meant to flow more quickly, making it suitable for larger aircraft. The drogue method however, means that up to three aircraft can be refueled at once, depending on their size, however, there are severe restrictions on aircraft size that can be refueled by this method. A B-1, B-25 or E-4 AWACS would just gobble up fuel just as fast if not faster than the drogue method could give it to the aircraft.


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## FLYBOYJ (May 25, 2005)

HealzDevo said:


> As I said I think the Boom method is something to do with fuel flow rates. Fuel is meant to flow more quickly, making it suitable for larger aircraft. The drogue method however, means that up to three aircraft can be refueled at once, depending on their size, however, there are severe restrictions on aircraft size that can be refueled by this method. A B-1, B-25 or E-4 AWACS would just gobble up fuel just as fast if not faster than the drogue method could give it to the aircraft.



You're right about the boom with its larger flow rate. If a drouge had to be used it's just means more refueling time. During the refueling operation you want to get in and get out ASAP.


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## DerAdlerIstGelandet (May 26, 2005)

Good points. I want to hook up with some USAAF Blackhawk guys and go up when they get refueled. I think it would be a pretty hairy time.


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## HealzDevo (Jun 1, 2005)

I hope this has solved the mystery for you. It isn't so much that the two systems are totally different in all ways but just that the fuel demands for one force are different from another, as are the aircraft available as tankers. I would not like to try to land a 707 tanker on a carrier, it would be as impossible as landing a B-25 Mitchell on a carrier was during WW2. There was a large aircraft with a lack of useable landing space, available.


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## plan_D (Jun 1, 2005)

Landing a B-25 Mitchell wasn't impossible, they did it!


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## DerAdlerIstGelandet (Jun 1, 2005)

The only reason they did not do it after the Doolittle raid was because they did not have the fuel to get back to the Carrier.


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## evangilder (Jun 1, 2005)

Not exactly. There were 2 reasons. 1 it was determined that landing on a carrier was very difficult and 2 it would have forced the Navy to loiter in unfriendly waters waiting for their return. That would also have forced them to use radios to tell them whether they were returning or not and give away their position.

The Navy was nervous enough about getting that close to the Japanese mainland. Hagning around waitinng would have been suicide.


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## DerAdlerIstGelandet (Jun 1, 2005)

I know it would have been difficult however I always thought the main reason was the carrier was not going to get close to the Japanese mainland and therefore there would not have been eneogh fuel especially in the stripped down Mitchels.


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## evangilder (Jun 1, 2005)

The plan called to take off between 400 and 600 miles from the Japanese coast. The closer the better. From Tokyo, China is another 1200 miles, Vladivostok, 600. If carrier landings could be more easily executed and the Navy was not nervous about loitering in bad-guy land, it may have been better that way.


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## DerAdlerIstGelandet (Jun 1, 2005)

I certainly agree. They may have all gotten home then.


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## evangilder (Jun 1, 2005)

True, but I can see why the Navy wouldn't want to hang out waiting. 2 flat tops are prime targets for the bad guys.


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## the lancaster kicks ass (Jun 2, 2005)

and there was barely enough room to take all of the B-25s off, trying to lad all of them on that flight deck would be rather akward, even with arrester hooks......


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## evangilder (Jun 2, 2005)

Good point Lanc. It would have been real tight for landing. Plus with the -25s on the deck, if the carrier was attacked, they would either have to take off again so the fighters could come up or the carrier would be a sitting duck.


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## plan_D (Jun 2, 2005)

You don't have to keep the B-25s when they land, just push them off the side. The USN did it enough during World War 2, Korea and Vietnam.


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## evangilder (Jun 2, 2005)

Always a possibility. They ended up losing them anyway. Though that was not in the plan.


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## the lancaster kicks ass (Jun 2, 2005)

the only advantage of doing that is getting the crews back, but they were going on to china anyway so it's no real advantage.........


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## DerAdlerIstGelandet (Jun 9, 2005)

Yes but if they had made it to China they would have gotten home. China was at war with the Japs too so they were allied with the allies.


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## wmaxt (Jun 22, 2005)

DerAdlerIstGelandet said:


> Yes but if they had made it to China they would have gotten home. China was at war with the Japs too so they were allied with the allies.



The Dolittle B-25s were always supposed to go to the Chinese/Flying Tiger Air Force. for use in China for use against the Japanese. There never was a thought of returning to the carriers.

The Droug/Boom issues are as follows:

1. The Speed difference of aircraft. Planes like the B-47 were atnear thier stall speeds while the KB-29/KC-97s were at absolute top speed, very hard on everything. Compounding this is the weight transfer complicates the situation. Air Force Transfers are frequently over 10,000lbs, Navy transfers are closer to 5,000lbs normaly.
2. Relative maneuverability is severly limited at/near stall speed while the boom was/is flyable, limiting the need to go after a droug.
3. Fuel flow. I think the boom flows 4/5 times the fuel per min.
4. Stability - the boom acts like a shock absorber and in some cases has been used to Tow aircraft that couldn't get fuel to conserve what they had for landing. This happened several times in the Vietnam war.

The Navy has other priorities namely weight and compact size. Naval aircraft are of more similar performance capabilities and some droug systems can be switched to different aircraft in a pinch.

wmaxt


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## DerAdlerIstGelandet (Jun 23, 2005)

wmaxt said:


> DerAdlerIstGelandet said:
> 
> 
> > Yes but if they had made it to China they would have gotten home. China was at war with the Japs too so they were allied with the allies.
> ...



I never said they were supposed to go to the Carriers. I said if they had made it to China they would have made it home, implying the crews would have made it home.


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## Joel Dobson (Feb 11, 2017)

The difference between the drogue method and the boom method may have been the amount of fuel transferred and the mission. The boom was actually very maneuverable: it could be moved by the KC 135 "Casey" up to 40 degrees down, 20 degrees up, and 10 degrees either side. It was 33 feet long and had another 12 feet that could telescope out and into the four inch fuel receptacle. Refueling of 120,000 pounds of fuel would usually take about 20 minutes for a B-52. It was called the flying boom because of the small wings on either side controlled by the boom operator.
And the reason they called the refueling operator "Casey" was because he lowered the boom.


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## soulezoo (Feb 28, 2017)

Hey, here's one I can help answer (for a change)

KC-10 crew chief here... with an awful lot of time having to fix damned booms and drogues.

First, keep in mind mission drives the gear.

Some of you have touched on a little of the why... but wait! There's more!

For the AF that has a lot of heavies to refuel (as well as puddle jumpers) it needs to move a lot of fuel fast and the boom does that. Also, must consider that the boom is far more stabile in flight. (while I don't recall the fuel flow rates exactly, I recall that a KC-10 can transfer as much fuel in 5 minutes as a gas station pump (for autos) can in 24 hours... or something like that, don't quote me exactly)

The Navy for the most part doesn't have to move a lot of fuel at a time as most of the acft are small and also there's the whole landing on a carrier thingie which helps to keep the acft size to a minimum.

The real reason is HELICOPTERS! It's awfully hard to fly a boom down between spinning rotor blades. Look at sea stallions or even Jolly Green Giants with the big probes that jut out in front to avoid the blades. The drogue just has to come in on the horizontal (rather than a diagonal for the boom). So, for standardization, Navy has probes on all it's acft.

Also, the 135's and KC-10's fly too fast for heli's... so even though they have drogues for navy, they don't do heli's.

Trivia: On KC-10's, if A-10's are in the mission profile, they must use KC-10's that are not modded with the drogue pods on the wings. This is because of drag and lift restrictions... the KC -10 cannot fly slow enough for the A-10 to keep up when the tanker has the drogue pods installed.

And remember: no one kicks ass without tanker gas! LOL

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## Robert Porter (Feb 28, 2017)

Found this for KC-10's: During boom refueling operations, fuel is transferred to the receiver at a maximum rate of 1,100 gallons (4,180 liters) per minute; the hose and drogue refueling maximum rate is 470 gallons (1,786 liters) per minute.

Found here: KC-10 Extender > U.S. Air Force > Fact Sheet Display

Might help a bit. Boom is almost 4 times faster than the drogue.


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## Old Wizard (Mar 10, 2017)




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## Koopernic (May 3, 2017)

Robert Porter said:


> Found this for KC-10's: During boom refueling operations, fuel is transferred to the receiver at a maximum rate of 1,100 gallons (4,180 liters) per minute; the hose and drogue refueling maximum rate is 470 gallons (1,786 liters) per minute.
> 
> Found here: KC-10 Extender > U.S. Air Force > Fact Sheet Display
> 
> Might help a bit. Boom is almost 4 times faster than the drogue.




From memory the HP Victor bomber modified as a tanker could transfer 1200lbs a minute for the wing tip pods and 8000 lbs for the central unit. Don't quote me on exact numbers but there were high flow probe and Droge units for heavy aircraft. Russian Bears refuel this way.


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## Zipper730 (May 20, 2017)

There were loads of methods of in-flight refueling proposed by people of all sorts in the 1920's and 1930's. The problem is they weren't always designs that would be reliable and practical for combat.

By 1934 there was a guy named Alan Cobham who was working on a looped-hose with grapnel line that he had in use by 1938 or 1939: It required multiple-man crew, but was actually used on at least one flying-bloat aircraft. The idea was to takeoff light, then refuel in mid-air with the hope of extending range 50%.

In 1942, the idea was tested by the USAAF and rejected. There were proposals that entailed sliding a drop-tank onto the wing of a P-38, that seemed to be rejected.

When the Air Force became independent: It was decided to develop an in-flight refueling system. The looped-hose & grapnel line was used first, but it's requirement for multi-man crews ruled out fighter-escorts. So eventually they went with what we now call the probe and drogue. When the US Navy started to develop nuclear-strike, this was implemented as well.

It worked fine for aircraft of fighter size up to even some jet-bombers, but for larger aircraft, it was a problem because of slow refueling times as mentioned. This gave way to the flying-boom, but it was only used by SAC at first (I'm not sure if MAC was using it at first). Starting in the late 1960's it was used by all USAF branches.


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## Graeme (May 20, 2017)

Zipper730 said:


> but was actually used on at least one flying-bloat aircraft.





There was one "bloat" (S.30 G-AFCU Cabot) that was refueled in flight from a Handley Page Harrow in '39.
900 gallons took 15 minutes to transfer.
Here's the mechanism inside the Harrow that controlled the refueling hose...

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## MiTasol (May 20, 2017)

Nonskimmer said:


> I've often wondered, and have never really found a satisfactory answer, as to why the US Air Force uses the exact opposite refuelling probe arrangement on it's aircraft from the Navy and Marine Corps.





DerAdlerIstGelandet said:


> To be honest I really dont know, but I would say it is because in tradition the US military can not agree on anything whether it is uniforms, equipment or aerial refueling.



That would be my guess too for the reversed connections.

Look at the Technical Orders (manuals) as another prime example. In WW2 the military started to have AN Technical Orders where the same manual was used by both services for aircraft and other material used by both services. That is why many of the wartime TO's have a number prefixed with AN for Army/Navy.

About the time the USAF became separate that fell apart -- even before the war was over the brass felt that fighting over document numbering systems was as important as fighting the enemy. They remind me of the seagulls in _Finding Nemo._

Seventy years later they still have the stupidity that all three services use the identical manual but each service has its own TO number and numbering system.

Military Intelligence at its finest OR a pack of spoiled three year olds, take your pick.

Either way maintaining three numbering systems costs the taxpayer three times what a single system would cost.

AND the brass behind this like to pretend they are responsible adults!


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## Zipper730 (May 20, 2017)

Graeme said:


>


Hahahahaha! Sorry about that!



> There was one "bloat" (S.30 G-AFCU Cabot) that was refueled in flight from a Handley Page Harrow in '39.
> 900 gallons took 15 minutes to transfer.


60 gallons a minute...



MiTasol said:


> Look at the Technical Orders (manuals) as another prime example. In WW2 the military started to have AN Technical Orders where the same manual was used by both services for aircraft and other material used by both services. That is why many of the wartime TO's have a number prefixed with AN for Army/Navy.
> 
> About the time the USAF became separate that fell apart -- even before the war was over the brass felt that fighting over document numbering systems was as important as fighting the enemy.


Why?


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## Shortround6 (May 21, 2017)

MiTasol said:


> Either way maintaining three numbering systems costs the taxpayer three times what a single system would cost.
> 
> AND the brass behind this like to pretend they are responsible adults!



They are _responsible _for maintaining their own positions/jobs for themselves and future generations of officers in their respective services.


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