Here's some speed from Yanks for Allied bombers and a couple German Scouts just for comparison:
Breguet B-2 Speed 121mph; OC 20,340
Liberty DH-4 Speed 125 mph; OC 19,500 empty -- much less depending on bomb load -- 5,000 feet when fully loaded. IIRC the Brit Liberty DH-4 with the Eagle Engine delivered similar performance.
DH-9a Speed 123 mph; OC 18,000
Fokker D.7 (160 hp Mercedes) Speed 118 mph; OC 19,600
Fokker D.7(F) (185hp BMW) Speed 125mph; 21,000.
Sopwith Strutter (bomber version) 96 mph; OC 8000 feet.
Hadley Page Bomber 79mph; OC about 10,000 feet
As you can see most late war bombers are actually faster than every German Scout save the Fokker D.7(F). The Mercedes 160hp engine was pretty much standard in most German Scouts. This engine was not high compression and did not do well at high altitudes.
Unencumbered by bombs, the late war Allied day bombers can generally climb as well or better than German Scouts (D.7(f) excepted). The slower types were relegated to night bombing missions.
The most 'fragile' of the late war bombers is probably the American Liberty D-4. Pilots were afraid to open up the throttle because they feared full power would tear the plane apart. Still it's pretty clear they were quite capable of outpacing the Fokker D.7(F)'s of JG II.
There is a lot of mis-information out there and too many rules portray day bombers as very slow, rather easy targets. Such was not the case. Often the Germans were only just able to intercept a formation and make a single pass before being left behind.
The reasons for this is that when the bombers were 'in bound' they proceeded at very high altitudes and it took the German Scouts all kinds of time to climb and close with the Bomber formations. Seldom were the bombers engaged when approaching their target. The German Scouts were generally able to position themselves to intercept the out bound day bombers but did not always have enough time to close with them before the bombers left them behind. The SSW-3 and SSW-4 aircraft had a rather phenomenal rate of climb and these were to be employed as point defense aircraft. Unfortunately for the Germans they never played much of a part because of engine problems and the inability of the Germans to develop an adequate lubricant for the Halske engines.
mjc