World War II US Gunships: YB-40 Flying Fortress and XB-41 Liberator Bomber Escorts

I am a big fan of the WWII "Gunship" escorts and this book delivers everything it promises.But...I would have loved some more info on the B-29 escort prototype.

This is the best book I have encountered on the rare YB-40 and XB-41 bomber escorts. It describes the conceptual or theoretical planning behind the designs, the modifications of the standard B17E and B24D airplanes to create them, and their deployments in the ETO. The book also describes the service histories and fates of each of the YB-40s sent to England. It doesn't take much effort to do so, since only 13 were deployed. They performed only 48 sorties. There is much discussion on the armaments of the designs. For the time, the turrets and hydraulic power control systems were quite sophisticated. There is also much discussion on the reasons for the failures of the bomber escort concept: excessive weight, poor maneuverability, poor rate of climb, armament not significantly greater than a standard B-17F.The book "American Aircraft Development of the Second World War: Research, Experimentation, and Modification 1939 - 1945" by Norton (2019) discusses the YB-40 and XB-41 designs in pages 340 - 348. The only other book I have found that mentions them to any serious degree is "American Combat Planes" by Wagner (1960) in pages 125 - 128.

Todo

Used for reference. Bold concept let down by reality.

Ｂ－１７Ｆで英国から独逸占領下の仏国や独逸への白昼戦略爆撃を敢行してた米第８空軍の悩みの種が、当時、爆撃機をフルエスコートできる戦闘機が存在しなかったことであった。英仏海峡は英空軍のスピットが護衛したが、独逸占領下の仏から独本国の間は、強力なドイツ空軍のメッサーが果敢に迎撃して来た。これに対抗すべく開発されたＢ－１７ＦがＹＢ－４０で重武装のＢ－１７でした。機銃も然ることながら銃弾の搭載量が膨大だったため投弾後の爆撃機編隊に追従できないなどの問題も有り、大量生産されることなく、ＸＢ－４０所以の顎砲塔装備のＧ型の出現とＰ－３８やＰ－４７と言った長距離戦闘機の出現でニーズの消えた長距離援護戦闘機がＸＢ－４０ですが、その専門書と言っていいでしょう。