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Bristol Blenheim Mk IV


  • Open both Rotary Fuel Cocks on the rear right cockpit wall by rotating them fully Clockwise.
  • Slide the Fuel balance Cock behind the rotary cocks to the forward position.
  • Set throttles slightly open
  • Mixture NORMAL (AUTO RICH)
  • Close Cowl Flaps fully.
  • Start engines in turn Left then right (Order is important you work out why)
  • Advance throttles slightly (avoid rough running) to warm up.
  • Monitor Cylinder Heat Temp at 100C set cowl Flaps full open.
  • Min CHT 100C
  • Min Oil Temp 40C.


Take Off can be performed at +5Lbs Boost or +9 Lbs Boost with boost cut out Enabled.

It is recommended that boost Cut Out is used for takeoff. In Real life a +5Lbs Boost take off was performed with Cowl Flaps closed. A +9Lbs take off with Cowl Flaps 1/4 Open. For ALL take offs in the TF Blenheim Cowl Flaps should be set to 1/4 Open.

  • Set flaps 15 (Or up for Light weights)
  • Check Props set to Full Fine Pitch (Plungers IN or to rear)
  • If +9Lbs required set Boost cut Out Lever to Down (Active Position)
  • Smoothly advance Both throttles to fully forward.
  • When Safely airborne Landing gear Up. (beware trim change)
  • Flaps UP (beware trim Change)
  • Deselect Boost cut Out (lever UP)
  • Select +5lbs Boost
  • Select Coarse on Prop pitch (Plungers OUT or forward)
  • Check CHT … adjust cowl Flaps if required.


  • +5Lbs Coarse Pitch
  • Climb at 135MPH IAS to 6000ft then reduce by 1 Mph per 1000ft
  • CHT 190-210C


  • +3.5Lbs Boost
  • Monitor CHT adjust Cowl Flaps to maintain 190C

Combat Concessions (5 Min)

  • +5Lbs Boost Coarse
  • Max CHT 235C


Long Cruise descents from high altitude at Idle power with cowl Flaps closed can result in approaching Min CHT of 100C. If this happens advance Boost slightly as required to ensure CHT is kept above 100C


  • On Final set Props Full Fine (Plungers IN or to rear)
  • Consider cowl Flaps 1/4 Open (in case of Go Around)
  • Approach IAS 85MPH min

WARNING High Rates of Descent at <85MPH IAS can result in running out of elevator authority in the flare.


  • Cowl Flaps Full open
Min CHT 100C
Max CHT 235C
Min Oil Temp 40C
Max Oil Temp 85C
  • +9Lbs 5 min or temp Limits (OIL/CHT)
  • Max IAS 285MPH
  • Flaps 145MPH
  • Trim Changes
  • Landing gear Down Nose Up
  • Flaps down Nose Down


The Blenheim has 4 fuel tanks. 2 Tanks in each wing referred to as Inner and Outer tanks. Fuel quantity gauges are located above the pilots left shoulder. Two gauges are present to indicate the fuel remaining in both Port and Starboard tanks. Each wing has two tanks Inner and Outer. To read a specific tank Fuel Quantity first select the desired tank using the the rotary switches.


The Bomb aimers station has a number of player controls. Two Yellow Manual Bomb release buttons are located on the Chart table.

A total of 4 switches are located on the forward instrument panel. These Mode switches allow the bomb aimer to select Bomb delivery modes.

Course Setting Bombsight Operation.

The Blenheim MKIV is equipped with the Course setting Bomb sight. This is a simple vector sight that provides an aiming reference for bomb release. The Bomb aimer inputs Bomb release HEIGHT and GROUND SPEED and drift. It is important to understand that the Bomb aimer must input Bomb Release HEIGHT not Altitude. Bomb Release Height = Altitude – Target Elevation. In addition the Bomb Aimer must determine the GROUND SPEED and input this to the sight. So the Bomb aimer needs to first determine TAS then apply the wind to determine the ground speed. In Nil wind conditions TAS = GROUND SPEED.

The Sight consists of a vertical post which combines as the Height scale and back sight. The back sight consists of an aperture with the Tgt Height Ref index pin on the right and left sides. A scale on the vertical arm shows the current Height set by the bomb aimer.

The sight also has a horizontal arm with attached Track reference wires. The Horizontal arm also has the foresight which consists of the Ground Speed Ref index pin. The horizontal arm has two ground speed scales. The White scale on the left (not visible with zero drift) has a mph scale. The Red scale on the right is also a Ground Speed scale but in “Minutes to fly 60 miles”. This is easily visible in most situations.

In the graphic below The Release Height is set to 7000ft. The ground Speed is set to 12Min to cover 60 miles i.e. 5 miles per minute or 300mph Ground Speed. To obtain the correct aiming reference the Bomb Aimer moves his Eye line to line up both the Ground Speed ref pin and the Release Height ref pin….i.e. Like with a Rifle he aligns the backsight with the foresight. In the Sim in bombsight view the eyeline is automatically set for you. With these Ref pins aligned the bomb aimers eyeline is now on the correct release angle sight line.

With these settings the aircraft is then flown so the target passes through either the Left Aiming aperture or the right aiming aperture. (In the sim it needs to be the right aiming aperture)The Bombs are manually released as the target passes through and adjacent to the ref pins.

In Drift situations the Bomb aimer lays of the drift so that ground features are tracking directly parallel to to the horizontal arm and its drift wire reference lines. The aircraft is then flown to ensure the target tracks down the Drift wire guideline to the aiming aperture.

Red Minutes to fly 60 miles to Miles per Min and MPH.

  • 30 = 2miles per min = 120mph
  • 25 =2.4miles per min = 144mph
  • 22 = 2.7 miles per min = 164mph
  • 18 = 3.3 miles per min = 200mph
  • 14 = 4.2 miles per min = 257mph
  • 12 = 5miles per min = 300mph


In the Sim you can simply use the digital values of release height and ground speed to set the sight accurately rather than refer to the respective scales.


These are Automatic. the Doors are held close by Bungee operation. The weight of the falling bomb will open the doors which will then snap shut after bomb release.

Air Intake Heat Control

Required ON for all operations in cloud or if rough running occurs for no obvious reason.

Mixture Control

In CLOD there is little value in running mixture in any other setting than AUTO RICH “NORMAL”, Fully to the rear. In NORMAL you will get automatic Altitude compensation on the Rich schedule. If you have a real need to minimise fuel Burn then mixture can be set to AUTO LEAN “WEAK” which is fully forward. In WEAK (AUTO LEAN) you will also get altitude compensation but on the Weak schedule. IRL there were Boost limits in WEAK, these have not yet been tuned in TF V1.0

blenhiem_mkiv.txt · Last modified: 2013/03/23 19:48 by Ivank