USA rushes in to prevent 1940 German invasion of the UK

[Carl Schwamberger]

Very few US fighters arrived in time for the BoB.

From the UK archives, US fighter types delivered to the RAF, 3rd September 1939 - 3rd September 1940:

19 Buffaloes
88 Mohawks

That compares to 1,782 Hurricanes and 862 Spitfires produced over the same period.

I think those were from a British order. The French had some 300 aircraft ordered from the US enroute. Either at sea or on US docks. Most of those were bombers. When the Franco German armistice was made public the British communicated to the US manufactors and government that they were interested in the French aircraft. They also made a effort to ensure those at sea went to British or nuetral ports rather than French. This was problematic as some were crated aboard the French aircraft carrier which was departing US waters in June. As I understand there were another 1200 US built aircraft scheduled for delivery to France before the end of 1940. Britian epressed a interest in accquirng control of those as well, plus and French orders for 1941 (3000+ ?). Since many of these were types the British had no interest or use for they sat in storage for some time & were not actually used by the Brits in England or in combat units. The 2644 fighters the Brits built themselves made the US aircraft redundant. Had the need arose a portion would have been available.

The exact numbers of fighters amoung the French order is unkbown to me. My impression is bombers were in a minority as the French were concentrating on types suitable for high speed low level attack missions.

The British will be in an enviable position regarding daylight aerial observation of aircraft than the French or Poles or any other nation who's airspace had been by then invaded by the Luftwaffe; a volunteer Royal Observer Corps that had been drilling and practising for a couple of years, an ARP organisation likewise trained in enemy aircraft recognition, and an activated Home Guard in the unoccupied areas of the country able to fill in gaps.

There is a overfocus on the 'Chain Home' radars here. Which suprises me considering the ammount of general knowledge amoung the folks who post here. Since age eight ( 1962) I'd understood the critical role the ground observers made to tracking and vectoring the RAF interceptors after then enemy had passed the early warning coverage of the CH system. The Brits DF radio stations were not fixed, and were not limited to coastal or exterior coverage. Neither were the traffic analysis stations. Those were also tied to the RAF info network and were used to locate the German attack groups, which had poor radio dicipline. Thought everyone had a grasp of these thing. I dunno maybe it is part of a infatuation with technology that leaves people thinking that if something is not advanced hardware it is vastly inferior. The bottom line is the RAF did not lose sight of the enemy bombers as they approached the coast. The visual system, and signals intel, were effcient in tracking them overland.

Aside from the network of reporting stations inland there were Naval patrols and picket boats in the Channel and North Sea whch reported as well.

A final question is the ability of the Brits to install a interior station in the Midlands. or to reorient one or more of the North Sea CH stations to cover southern Britian. I dont have any sources on my shelf for this, but suspect any German airbases in Kent could have been covered by a radar station.

[phylo_roadking]

There is a overfocus on the 'Chain Home' radars here. Which suprises me considering the ammount of general knowledge amoung the folks who post here. Since age eight ( 1962) I'd understood the critical role the ground observers made to tracking and vectoring the RAF interceptors after then enemy had passed the early warning coverage of the CH system. The Brits DF radio stations were not fixed, and were not limited to coastal or exterior coverage. Neither were the traffic analysis stations. Those were also tied to the RAF info network and were used to locate the German attack groups, which had poor radio dicipline. Thought everyone had a grasp of these thing. I dunno maybe it is part of a infatuation with technology that leaves people thinking that if something is not advanced hardware it is vastly inferior. The bottom line is the RAF did not lose sight of the enemy bombers as they approached the coast. The visual system, and signals intel, were effcient in tracking them overland.

The important thing about losing the coastal CH/CHL line is that Fighter Command loses advance warning of raids gathering over France that allows than to rest squadrons for refueling and rearming, and maximise aricraft in the air when needed, that comes with the deep ranging of radar over the French coast.

Carl, actually Fighter Command could and did lose sight of raids LOL there are a number of anecdotes of fighter aircraft turning up at their vectored interception points and nothing being there. And of course of undetected low-level raids appearing where they weren't expected. Information entering the analysis system from the ROC and ground stations in Kent and Sussex could be slow reaching Bently Priory, and the system then magnified this delay if a raid changed direction or height...which was something that happened a lot in the few days before the LW turned on London when they returned to attacks on Eleven Group's sector stations - and did a lot more damage than they had first time around. By this stage too Park was relying on Leigh-Mallory's squadrons to cover his northernmost Sector stations...and needed enough warning to request them. So any delay was dangerous.

The advantage of the ROC/ARP/HomeGuard/naval picket system is that its dynamic; the monitoring net can be extended, trained up, changed to cover the rest of the country if Kent and Sussex are lost, and those counties' coastal sections of CH/CHL lost with them. Yes, there were mobile stations by late October IIRC, but if the invasion starts then we're talking of a date around the middle of September for it happening, at the end of the summer weather window. Which might be too early to set up a crosscountry radar line using mobile units.

As for East Coast CH/CHL stations being reoriented - yes, the southernmost ones on the Norfolk coast and up towards the Wash can physically be reoriented, but it requires rebuilding and rejigging, but THEN that costs Fighter Command their coverage of the North Sea. While Chain Home stations are changeable, they're not instantly "switchable" - any change means moivng and rerigging the antennae - thus leaving the North of England open again to raids from Norway, this time without the warning that made the first attempts so costly. Also - I don't know what effect propagating a long distance over land has on Chain Home - using Norfolk and east coast stations to cover south-east England MAY mean some loss of definition over land and low-level coverage issues; remember, these are "line of sight" systems, not "over the horizon".

The one thing I have no problem with is Fighter Command being able to shift its own command-and control system north and fight the new air battle over land from there; a number of replacements for the Hole at Bently Priory were built around the country during 1940-41, including one rediscovered only in the last two years not far from where I'm sitting in Northern Ireland. And each Fighter Command Group had its Sector Control network for controlling fighters in the air once tasked by Bently Priory (or whoever). But as I said at the top of this post, what we have now is a major delay coming into the system, due to a degree degree of human and environmental error (poor visibility, weather etc.), leading to an increased need for confirmation of sightings and anticipated raids etc. - and no long-range warning of raids while they're lingering over France and formating.

I don't think that the recovering Fighter COmmand will be able to prevent any where near the same percentage of raids as they did during the initial (historical) BoB. A ground observation-based early warning net will not give them the same sort of "realtime" monitoring of the movement of enemy aircraft that radar did; they'll return to a "reactive" command and control, dependant on and vulnerable to reported sightings only. But they'll take a much greater toll of outgoing LW raiders, as these can at least be definitely tracked from the point at which they dropped their ordnance on "England's green and pleasant". Which in a battle of attrition is still vitally important...

[Carl Schwamberger]

The important thing about losing the coastal CH/CHL line is that Fighter Command loses advance warning of raids gathering over France that allows than to rest squadrons for refueling and rearming, and maximise aricraft in the air when needed, that comes with the deep ranging of radar over the French coast.

Not entirely. Aircrew chatter when forming up the raids was usefull both for radio direction location and other signal analysis. It appears Beppo Schmidt & the other German intel people underestimated Britiah capabilities in that direction as well.

Carl, actually Fighter Command could and did lose sight of raids LOL there are a number of anecdotes of fighter aircraft turning up at their vectored interception points and nothing being there. And of course of undetected low-level raids appearing where they weren't expected. Information entering the analysis system from the ROC and ground stations in Kent and Sussex could be slow reaching Bently Priory, and the system then magnified this delay if a raid changed direction or height...which was something that happened a lot in the few days before the LW turned on London when they returned to attacks on Eleven Group's sector stations - and did a lot more damage than they had first time around. By this stage too Park was relying on Leigh-Mallory's squadrons to cover his northernmost Sector stations...and needed enough warning to request them. So any delay was dangerous.

I know. I have Peter Townsends 'Duel of Eagles' on my shelf here & have read several of the other participants remarks. Nevertheless the system worked fairly well. Perhaps if a large portion of the CH system were destroyed, and a very large number of German aircraft were based on the forward airfield in England, and the British communications network failed to a critical point, then the RAF command and control advantage would be lost. But, as usual one has to ask how likely is all that with the existant German resources.

As for the rest of the radar questions I think I'd want to accquire a bit more educaton before deciding one way or the other.

[phylo_roadking]

Well, looking at the map - an actual invasion takes out Dunkirk (the english one), Dover, Rye, Pevensey, Poling, and Ventnor Chain Home stations, and Beachy Head, Truleigh, Foreness and Whitstable Chain Home Low gapfillers. That's a total of ten stations....

http://www.radarpages.co.uk/mob/ch/chainhome11map.htm

...and puts at least the CH stations in East Anglia and Norfolk i.e. north of the Thames estuary - at threat.

In other words - the Sealion plans takes out 32% of the September 1939 Chain Home sites, even if they survive the initial "Battle of Britain" campaign - the black dots; the white circles were extra CH sites added in the next 11 months to increase coverage around the coast in both directions, with the triangular Chain Home Low stations being built to fill gaps, like Pevensey to Poling along the southern coasts of Kent and Sussex, and Whitstable/Foreness plugging a gap along the south side of the Thames estuary (in other words, the Medway was left without radar cover!!!)

That is a BIG gap to lose...in fact, look at the map; apart from the "added" CHL station at Worth Maltravers, it's very nearly the entire south coast right across to the western edge of Devon

Be interesting to see a similar sort of map of Fighter Command Sector control rooms...to see how many of those would be lost or put at immediate risk by an invasion.

[Tim Smith]

A rough list of American aircraft still on order to France on 1 July 1940 (aircraft previously delivered not included):

270 Curtiss Hawk 75A (export P-36, later named Mohawk by the British)
130 Curtiss P-40 (later named Tomahawk I)
100 Curtiss P-40B (later named Tomahawk II)
675 Bell P-39D Export Model 14 (later named Airacobra I. No supercharger.)
200 Douglas DB-7 (later named Boston I)
100 Douglas DB-7A (later named Boston II)
100 Douglas DB-7B (later named Boston III)
100 Grumman F4F-3 (G36A export version, later named Martlet I)
75 Martin Model 167F (later named Maryland I)
417 Lockheed P-38 Model P-332 (later named Lightning I. No superchargers.)
(Historically of the 417 P-38s ordered by France, Britain only received 3 as the Lightning I. The USAAC took over the rest. 143 P-332 were built (used as trainers), then 36 P-38D with superchargers, then 210 fully combat-ready P-38E.)

2,167 aircraft in total.

[bf109 emil]

Jim - the problem is...the same multiplicity of requirements and demands issue affects them too. What Stukas can operate from inside the bridgehead will be essential for supporting the Army, and can't individually carry the bombload necessary for a "counter-force"campaign against British industry.

I agree using Stuka's for a long range bombing mission to destroy factories basically sent them to there death, but in a combat assist role they where invaluable...which hopefully they or would have been used had an airbase been established on British soil...there role in the BoB was doomed from the onset of speed and the fact radar could intecept them, something which the British other then observers had nothing set up for inland, once s force crossed the coast it was the responsibility of the Observer core to track flights...using slow Stuka's over a city which had ample AA or suitable number of fighters might have met the same fate as if the British used Tiffies to try and dive bomb a factory over a German city, at low altitude even with numerical air superiority...they'd have been slaughtered...but in a grow role assisting army or infantry they where invaluable...

[phylo_roadking]

I wonder what sort of a mess barrage balloons and cable bombs would have made of Stukas...

[bf109 emil]

I wonder what sort of a mess barrage balloons and cable bombs would have made of Stukas...

lol over cities imagine huge but in the field or against ground targets would have been kinda hard for an army to stay low key flying barrage balloons as an invite to there locale or disposition...any cable would have been nasty, as didn't even Lancs have cable cutting devices at the edge of their wing tip for this possibility?

[phylo_roadking]

I've never read of this, nor seen any pics with it fitted.

The problem is...that's what Britain in 1940 was covered in - cities and industrial targets. It's quite a small island, after all. It would be a toss-up between what's best...camoflaging factories or defending them properly - fighter cover, guns, barrage balloons. Once an invasion force is lodged in the south-east, I would doubt the British would opt for going too far and too expensively/time consumingly down the path of more camoflage. It might work against an occasional photo-recce flight, but in a post-landing air battle there's simply going to be too many enemy aircraft in the air over England to make camoflage really worthwhile. By the law of averages (if not Murphy's Law) somebody somewhere is going to be in a position sooner or later to view an objective from the wrong angle and see factory instead of trees or housing estates

[bf109 emil]

I'll have to have another look at a framed outline drawing/blue print i have showing the various parts, controls, etc. and i was sure it listed a cable cutter on the tip of the wing...will get back to you on this...

[bf109 emil]

I've never read of this, nor seen any pics with it fitted.

The problem is...that's what Britain in 1940 was covered in - cities and industrial targets. It's quite a small island, after all. It would be a toss-up between what's best...camoflaging factories or defending them properly - fighter cover, guns, barrage balloons. Once an invasion force is lodged in the south-east, I would doubt the British would opt for going too far and too expensively/time consumingly down the path of more camoflage. It might work against an occasional photo-recce flight, but in a post-landing air battle there's simply going to be too many enemy aircraft in the air over England to make camoflage really worthwhile. By the law of averages (if not Murphy's Law) somebody somewhere is going to be in a position sooner or later to view an objective from the wrong angle and see factory instead of trees or housing estates

some neat pics of the camouflaged Boeing plant in ww2

Under this detailed walkable camouflage roof of fake housing, Boeing B-17F Flying Fortresses were being produced in 1942-1945. The two women show the detailing done to make it look real.

I cannot find a pic of North American Aviation camouflaged plant in WW2 but it was well done as well

[phylo_roadking]

I presume that's on the roof of the plant the staked "path" is I presume the safe, weight-bearing portion of the roof! Note how everything is to scale - pint-sized houses and pint-sized trees and telephone poles...that would be used for scaling up the dimensions of the buildings

And that's exactly the problem; the mainland U.S. was only ever at the very worst going to come under high-level photo-recce, only ever in "lookdown" made; but with a tactical air battle going on day by day over the UK mainland, sooner or later someone would fly over a similar plant at an oblique angle like WE are priviledged to there, and the game's up...

[Carl Schwamberger]

I wonder what sort of a mess barrage balloons and cable bombs would have made of Stukas...

Somewhere on my shelf is a account by a German bomber pilot who tangled with a barrage ballon and cables. It was at night so he had no clue exactly how this occured. His initial impression was of the flight controls not working, then balloon fabric billowed up around the aircraft. The pilot then realized the Brit searchlights were entering the cockpit from above, apparently the aircraft had flipped over. Regaining partial control he spun thru AAA traces and bursts, skimmed across the harbor water, over some docks and eventually out to sea.

[phylo_roadking]

Somewhere on my shelf is a account by a German bomber pilot who tangled with a barrage ballon and cables...

...by the end of that sentence it was clear the story would have a happy ending!

In reference to the stukas, I was thinking more of that post-release high-G grey-out moment...

[bf109 emil]

A rough list of American aircraft still on order to France on 1 July 1940 (aircraft previously delivered not included):

270 Curtiss Hawk 75A (export P-36, later named Mohawk by the British)
130 Curtiss P-40 (later named Tomahawk I)
100 Curtiss P-40B (later named Tomahawk II)
675 Bell P-39D Export Model 14 (later named Airacobra I. No supercharger.)
200 Douglas DB-7 (later named Boston I)
100 Douglas DB-7A (later named Boston II)
100 Douglas DB-7B (later named Boston III)
100 Grumman F4F-3 (G36A export version, later named Martlet I)
75 Martin Model 167F (later named Maryland I)
417 Lockheed P-38 Model P-332 (later named Lightning I. No superchargers.)
(Historically of the 417 P-38s ordered by France, Britain only received 3 as the Lightning I. The USAAC took over the rest. 143 P-332 were built (used as trainers), then 36 P-38D with superchargers, then 210 fully combat-ready P-38E.)

2,167 aircraft in total.

here is a list of aircraft and engines ordered from a confidential file from the fdr library. It list type and number ordered, by what country, and what was actually delivered. this first document shows craft and supplies to Australia, Canada, and Great britainhttp://www.fdrlibrary.marist.edu/psf/box3/a40b01.html
-this second order was for aircraft ordered by France and what was delivered or filled and what was not sent because of an embargohttp://www.fdrlibrary.marist.edu/psf/box3/a40c01.html