Posted back in post #1616. This are dates and weights of the P-400 project gaining weight from Bell records according to Birch Matthews.
date.............................Empty...................useful load...................Gross...........................notes
Feb 1940....................4,524.......................1,325...........................5,849............................1 cannon, two machine guns
March 1940..............4,715.......................1,285............................6,000............................2machine guns added in each wing
May 1940.................5,149........................1,841............................7,000............................wing gun caliber increased
July 1940...................5,383.......................1,974.............................7,350...........................Armour and self-sealing tanks added
Jan 1941....................5,406.......................2,006.............................7,466...........................Minor empty and useful load increases
June 1941.................5,548........................2,087.............................7,635.........................Engine and fixed equipment weight increases
July 1941...................5,550.......................2,087..............................7,637..........................actual weight of Serial number AH 621
Now to splice in some other dates.
date.............................Empty...................useful load...................Gross...........................notes
Feb 1940....................4,524.......................1,325...........................5,849............................1 cannon, two machine guns
March 1940..............4,715.......................1,285............................6,000............................2machine guns added in each wing
April, 1940, French order 165 planes after several weeks (months?) of talks.
May 1940.................5,149........................1,841............................7,000............................wing gun caliber increased
July 1940 work is completed on the British take over of the French order and add 5 planes,
July 1940...................5,383.......................1,974.............................7,350...........................Armour and self-sealing tanks added
Sept 1940, The US orders the P-39D and changes the P-39C order form 80 planes to 20 Cs and 60 Ds.
Sept 1940, the first YP-39 is completed
Jan 1941....................5,406.......................2,006.............................7,466...........................Minor empty and useful load increases
Jan 1941, First P-39C is completed
Jan 1941, The British and Bell agree on changes to the P-400 specification.
March 1941The US passes the lend Lease act.
APRIL 1940, P-400 AH 571 flies, the modified one that just barely passes the speed test.
June 1941.................5,548........................2,087.............................7,635.........................Engine and fixed equipment weight increases
July 1941...................5,550.......................2,087..............................7,637..........................actual weight of Serial number AH 621
July 1941The British and Bell agree to the last modification of the P-400 specification. and order 505 additional planes.
July 1941, the 3 lend lease P-39Cs show up in England for familiarization before the the production P-400s show up.
July 1941, end of July the first production P-400s show up in England.
Now who knew what and when???????
British don't seem to have ordered the "heater" unless there is direct evidence they did so. the French order the four wing guns.
The British just went along, or didn't have them taken out.
By Sept 1940 the US is going along with the four wing guns and going along with the armor and self sealing tanks.
So when did the British make the changes so they could get out of the contract and get the planes free with lend lease????
Jan is too soon as lend lease doesn't exist yet. July is too late as why bother to order 500 planes with specifications you are trying to screw up???