Blenheim operating limits and checklists

[phoenix1963]

The pitch does now seem to be variable in the one third portion closest to coarse setting.

Right or wrong, it proves quite useful, I can now climb at about 2150 rpm, +2lbs boost, +1000 ft/min. But I still have to have the gills open ~70%.

As Robo says, shaking sets in at almost 5000 ft, indicating the need for carb (intake) heat.

Best news (unless I missed it before the Beta) is that the sight now has sideslip adjustment!

56RAF_phoenix

[Blackdog_kt]

I think sideslip correction was only mentioned for the German Lofte sights? I could be wrong, but i didn't see it with the mechanical sight in the Blenheim.

In any case, the correction that does get applied automatically in the Blenheim is an angle of attack correction. In reality i guess it was manual, what happens in the sim is that it needs some time of straight and level flying while the bombardier automatically adjusts this. In short, it's just a matter of correcting for how up/down your nose is pointing when on level flight due to weight differences between sorties (a heavier aircraft will need more nose up trim than a lighter one to maintain level flight, assuming they are flying at the same speeds).


As for the propellers, i was under the assumption that the method of obtaining semi-adjustable RPM didn't involve setting the prop controls mid-way, but manually and constantly alternating between the two positions, ie a case of increased pilot workload and as such, useful only for specific phases of flight.

There's a video on youtube by A2A simulations (the guys who made the Spitfire add-on for FSX) aptly titled "propellers" which demonstrates the method. I tried it in CoD with a Spit Mk.I and it works, but you have to be wary of your boost: coarsening the pitch as much as the two-stage props do results in a substantial rise of manifold pressure, so set your throttle for an in-between boost value that won't exceed maximums when at coarse pitch.

[IvanK]

"As for the propellers, i was under the assumption that the method of obtaining semi-adjustable RPM didn't involve setting the prop controls mid-way, but manually and constantly alternating between the two positions, ie a case of increased pilot workload and as such, useful only for specific phases of flight."

I think that assumption is incorrect Blackdog Kt The Spit manual implies that its just a matter of using the Prop pitch control as a Vernier device that enables you some additional control of Prop pitch other than just the Coarse and Fine stops. The location of the Prop pitch control in the Spit I makes it a little easier to manage.

As to the Blenheim with the controls mounted behind and under your left elbow and 2 to fiddle with that would be imo virtually impossible. As indicated in my earlier post there are no references at all to the Blenheim IV (and I) props being capable of intermediate settings other than Fine and Coarse.

[phoenix1963]

Originally Posted by Blackdog_kt

I think sideslip correction was only mentioned for the German Lofte sights? I could be wrong, but i didn't see it with the mechanical sight in the Blenheim..

Blackdog - There's an adjustment knob/nut on the right hand side of the Blenheim sight that rotates it left or right to allow for wind/sideslip. I don't know much about sights, so maybe I simply missed it before!

56RAF_phoenix

[Blackdog_kt]

Good to know, i'll try it out next time i'm flying that temperamental coffin
I have all the bombsight functions mapped to my numeric keypad with shift and ctrl combinations, i'll have a look at it.

Also, thanks to IvanK for the renewed feedback