Drop Tanks

[KJ_Lesnick]

When were drop-tanks first conceptualized (not actually used, just drawn up as an idea)
1: On Earth
2: In the United States

[scooter]

When were drop-tanks first conceptualized (not actually used, just drawn up as an idea)
1: On Earth

According to Wikipedia-

The drop tank was first[citation needed] used during the Spanish Civil War to allow fighter aircraft to carry additional fuel for long-range escort flights without requiring a dramatically larger, heavier, less maneuverable fuselage. During World War II, the German Luftwaffe began using external fuel tanks with the introduction of a 300 liter (80 US gallon) light alloy model for the Ju 87R, a long range version of the Stuka dive bomber, in early 1940. The Messerschmitt Bf 109 fighter also used this type of drop tank, starting with the Bf 109E-7 variant introduced in August 1940. Fitted also to the Focke-Wulf Fw 190, 300 liter became the standard volume of subsequent drop tanks in Luftwaffe service.

2: In the United States

Drop tanks were prohibited on fighter aircraft and on medium bombers by the so-called Bomber Mafia in the United States Army Air Corps prior to direct U.S. involvement in World War II. The bomber theorists assumed that bombers would be self-defending; they saw long-range fighters as "a myth",[1] as they could be easily forced to drop the tanks by minor harassment just at the beginning of the raid.[1] Long-range medium bombers were viewed as direct competition to their goal of vast air fleets of heavy bombers.[2] Starting in 1941, airmen such as Benjamin S. Kelsey and Oliver P. Echols worked quietly to get drop tank technology added to American fighters such as the Lockheed P-38 Lightning. It was only with drop tanks supplying at least 450 US gallons (1,700 l; 370 imp gal) of extra fuel per fighter that the P-38 could have carried out Operation Vengeance, the shootdown of Admiral Isoroku Yamamoto.[3] Even after such experience showed the necessity for drop tanks, inflexible thinkers such as General Ira C. Eaker had to be transferred out of commanding positions so that drop tanks and range extension plans could be widely implemented in 1944 for American escort fighters.[4] External drop tanks also turned the Republic P-47 Thunderbolt from a short-range interceptor into long-range escort and air superiority fighter, enabling it to accompany bombers all the way from British Isles to Germany, and back.

And the reference link: http://en.wikipedia.org/wiki/Drop_tank

[PR19_Kit]

In the UK Spitfire Vs onwards could carry droppable belly tanks, they called them 'Slipper tanks', and they came in 3-4 sizes from around 30 gallons to monster 170 gallon tanks.

Having said that they tended to be used on the long range PR versions rather than the fighters. Fuel use was critical with the 90 and 170 gallon tanks as they had to be emptied first or the CG would go out of limits. My Dad hated flying with the 170 gallon tanks just because of that problem.

[rickshaw]

Were the slipper tanks jettisonable?  I was under the impression the big ones weren't and were meant for ferry missions, rather than operational use.

[PR19_Kit]

Apparently so, the rear end was held on by two hooks and the front connection was operable from the cockpit. When they were released the front end fell down and the drag pivoted the tank around the year hooks till it dis-connected. Must have been a bit of a surprise for any poor soul near where they fell to earth as they were socking great chunks of metal!

They didn't need the 170 gal. tanks to get to Berlin and back with either the PRXI or the XIXs either, as both had the 'bowser' wing tanks' but did use them occasionally for very long range flights over more than one target.

[PR19_Kit]

I just found this page which has some interesting stuff about two US modified Spifires using both the smaller slipper tanks AND two P-51 tanks to fly non-stop across the Atlantic. Plus it mentions later use of similarly fitted Israeli Air Force Spitfires in combat!

http://spitfireforums.com/index.php?topic=41.0

[tahsin]

Lots of many post-WW1 types have external fuel tanks on the belly and the like, it wouldn't have too big a step to conceptualize to drop them in an emergency or combat. Although the F-11 Goshawk is not that distant from the Civil War in Spain .

[Logan Hartke]

I just found this page which has some interesting stuff about two US modified Spifires using both the smaller slipper tanks AND two P-51 tanks to fly non-stop across the Atlantic. Plus it mentions later use of similarly fitted Israeli Air Force Spitfires in combat!

http://spitfireforums.com/index.php?topic=41.0

Except those are German tanks!  Very cool!

Cheers,

Logan

[The Wooksta!]

The Isreali Spits had German drop tanks as they were supplied by the Czechs and used during the ferry flights (through Yugoslavia and they wore Yugoslav markings).  The CMR Spitfire LF.IXe in Czech/Isreali service comes with a set of Luftwaffe 109 drop tanks.

[PR19_Kit]

I just found this page which has some interesting stuff about two US modified Spifires using both the smaller slipper tanks AND two P-51 tanks to fly non-stop across the Atlantic. Plus it mentions later use of similarly fitted Israeli Air Force Spitfires in combat!

http://spitfireforums.com/index.php?topic=41.0

Except those are German tanks!  Very cool!

I was just quoting the text on the page.......

[KJ_Lesnick]

The F11C had them.  Were they from the get-go or within a few years of service?

[tahsin]

This I can't possibly say. Had hoped to find some conformal belly mounting on the likes of Siemens Schuckert types to no avail. Regarding Curtiss , it appears the F9C had similar facilities. When deployed on the USN airships as a parasite a couple of them once were tasked with overflying Roosevelt's yacth and they had their drops underneath. Possibly because of unfamiliarity the crew of the ship were alarmed enough to think they were under attack with "bombs" visible under the planes.

[pyro-manic]

The F9Cs actually had their landing gear removed and replaced with a fuel tank while on board the airships. I don't know that you could term it a "drop" tank though, as I don't think it was meant to be jettisoned.

[tahsin]

The intent seems to be finding a first-date for the concept and my first post also mentioned the fixed belly tanks. Having read the Wikipedia article on the F-11C I see 1932 mentioned with the central pylon suitable for bombs, the drop tank taking advantage of capacity. One might look into the first designs that had their landing gear "seperate" , not with the central aerofoil section so familiar with the WW1 planes.

[tahsin]

I knew it was somewhere, but wasn't sure about the designation. But here it is what I was talking about. The SSW D.VI has the fuel tank under fuselage and it can be dropped in case of a fire. Not as an extra for range extension, but it could glide down kind of safely after combat damage instead of burning to cinder in the air.