The Prop pitch selection in the Blenheim IV was I believe straight out Fine or Coarse without any "wiggle room". In the case of the Spitfire MKI the Wiggle room and technique on how to get benefit of it is clearly stated in the Spit Manual. To all intensive purposes it provided similar pitch control to what we see in the 109E though ergonomically not as well set up. No such mention of this wiggle room is mentioned in the Hurricane I manuals though. Here is an excerpt describing its operation from the Spit I pilots notes:
In the case of the Blenheim MKIV (and MKI) there is no mention at all of any wiggle room in the propeller pitch department in the Pilots notes. Neither is their any mention of it in Graham Warners exquisite book that covers engine handling in great detail. Nor is there any mention of it in the RAE Flight test reports available in the National Archives which cover engine handling in reasonable detail. Two of these reports are in relation to achieve Max possible climb performance and max level speeds.
As to handling with particular reference to Take off as we see it in the Sim the Yaw on take off is grossly over modelled. Again the Pilots notes state ... "Turn into wind, straighten up and opent the throttles together,taking only two or three seconds in doing so. ..... There is a slight tendency to swing to the right which is easily overcome by the rudder." Whats more telling is that the recommended Rudder trim setting for take off is neutral. There is no way we should have an aeroplane that we struggle with maintaining directional control with asymmetric power and stabs of brake.
With respect to Engine RPM in SIM versus Real world there is a large mismatch. Again the RAE reports give good details here. I "think" the issue in the Sim is how propeller pitch has been set this results in out of wack RPM values for a Given Boost and TAS. There is a fair bit of discussion in the RAE reports on setting up the Prop pitch stops for coarse with the intent that Full Coarse at Full throttle height should provide max RPM i.e +5Lbs Boost Prop Full Coarse around 2700RPM:
Here is the test data on RPM Versus Altitude V TAS again Coarse pitch
The RAE reports also provide copious data on Engine cooling. Clearly the Sim is way to critical in this area, I think Phoenix is spot on. Cylinder head temperature and Gill position is way to sensitive/critical.
A great insight to the Blenheim IV and its handling and engine operation etc is the Flying Machines "Flight of the Blenheim" DVD.
http://www.flyingmachinestv.co.uk/page2/page2.html
Warning slight but related thread drift follows.
With respect to Propeller pitch issues this imo is a common oddity in the Sim that may go some way to explaining the shortfall in performance in the 2 pitch Spits even at only 6Lbs boost (avoiding the 100 Octane debate
. Looking at multiple RAE reports that provide RPM versus IAS/TAS V Altitude for the early Merlins then repeating the tests in the SIM will see the SIM RPM consistently 300-400RPM less than real world.