Il2: Cod - Trng - Blenheim Checks

By K-9

For those who are attempting to take off in a Blenheim Bomber and are having difficulty, this may help.  It's posted at the 1C Clod Forum.

Take-off:

Mixture auto-rich (levers back) 

Prop Pitch fine 

Cowl flaps 1/3 open when on long range load (long range load = all fuel tanks loaded), closed when on normal load (normal load = inboard tanks only) 

Flaps at 15 degrees when on long range load (can't be done in the sim yet, it has two-position flaps but they should be more like the Hurricane's with up/down/neutral settings to enable the pilot to set them partially open) 

Boost cut out on for long range load, off for normal load. With the cut-out enabled you can get +9 psi boost BUT it needs 100 octane fuel. In the real one, the outboard tanks were 100 octane and the inboard ones 87 octane. I don't know if this is reflected in the sim, so i don't use the boost cut-out just in case it's modeled with 87 octane across the board for all fuel tanks. Normal max boost with the cut-out disabled is +5 psi. 

Let the tail rise and the aircraft to lift off. Then, gear up and keep it mostly level to accelerate. Once you hit 120mph switch to coarse pitch, then climb only mildly to let it accelerate to 150 mph which is the best climb speed. 

Disengage boost cut-out before throttling back if you had it engaged. 

Climb:

Keep within the engine limits by adjusting cowl flaps position. Oil temps up to 80 degrees, cylinder head temperatures (CHT) up to 200 degrees.

In the sim you can push the CHT up to 250 and the engines feel mushy below 180, so i keep it between 180 and 230. 

Best climb speed at full throttle is 150 mph up to 10000ft. For every 5000ft extra, reduce climb speed by 10 mph:

150mph IAS up to 10000ft 

140mph IAS up to 15000ft 

130mph IAS up to 20000ft 

Cruise:

It's possible to fly at very low throttle settings, resulting in less than 1600 RPM. 

Absolute 5-minute limit for level flight is 2750 RPM at +5 psi boost. It shouldn't be exceeded unless in an emergency. 

Engine power limits for cruise

for auto-rich/normal mixture (mixture levers fully back): 2400RPM at +3.5 psi boost 

for auto-lean/weak mixture (mixture lever fully forward): 2400RPM at +1.5 psi boost 

Lowest fuel consumption cruise: mixture auto-lean/weak and throttles back as far as it's possible to maintain level flight. 

Maximum range (most miles per gallon) cruise: Slightly higher speed than the one for lowest fuel consumption. 

Maximum range at 15000ft is obtained at 110mph IAS. In lower altitudes it's impractical to fly that slow (due to disturbed air), so 130 mph is used for extended range when flying low. 

Cowl flaps should be closed for economy cruise. I don't know if this is reflected in the sim, but running on rich and between +0 to +1 psi boost i can certainly close them more than halfway (i keep them about 1/3rd of the way open). 

Diving:

Maximum permitted speed: 285 mph IAS 

Engine RPM: up to 2750 if throttle is less than a third of the way open, at more than 1/3rd throttle up to 3100 RPM is permitted for a very short time (manual says momentarily). 

Prop pitch should be coarse (prop pitch controls fully back, everything above that in the sim corresponds to the fine pitch position). 

Landing:

Throttle back to bleed off speed, close cowl flaps if necessary to maintain CHT.

This is very important, because if you just idle it and keep it there on a steep, long descent for an immediate flare and touchdown afterwords, your engines will cool way down and not develop any power when you need it for the flare and touchdown and you'll pancake onto the runway.

It's also very important to remember to open the cowl flaps again once you apply throttle, in order not to damage the engines. Try to make it a habbit of adjusting them together: Throttle up- open cowl flaps some, throttle back- close cowl flaps a bit 

Once below 150 mph IAS, lower gear and set fine prop pitch. 

Enter the airfield circuit at 120 mph IAS. 

Drop full flaps when nearing the end of the circuit. The manual doesn't state more but full flaps sure is draggy in the sim, so i would say fly a normal rectangular pattern with gear down and drop flaps when turning from base leg to finals.

Turning with both gear and flaps extended presents a ton of drag and shaves off quite a bit of altitude, leaving you to execute a fairly flat approach instead of a normal glide. And to keep it flat (ie, level) at such high drag you need a lot of power while you're at a low airspeed-->overheat danger.

So, it's better to wait until you are aligned with the runway before lowering flaps. 

Missed Approach and Go-around:

Raise the gear immediately after leaving the ground to minimize drag. 

Don't raise the flaps until you reach a safe altitude of 500 feet. First, nose down a bit to accelerate to 100mph IAS, then raise the flaps. 

If one engine fails during the go-around, there is not sufficient power to complete the take-off at this high drag configuration. In such a case, closing throttles and landing at whatever cost is the only option. 

After landing:

Open cowl flaps while taxiing if the temperatures are high. 

If the aircraft is going to storage, change to coarse pitch before shutting down. If the props don't change over to coarse while taxiing, step on the brakes and throttle up a bit until the pitch changes (throttling up builds the necessary oil pressure for the prop governors). 

Close throttles for about a minute to allow the oil to settle in the sump. 

Stop engines by pulling the carburetor cut-outs. In the sim they are called slow running cut-outs and they are obscured, behind and to the left of the pilot's seat.

Just map a key to it, select engine one and hold, not press, hold it down the slow running cut-out key until it stops. Select engine two and repeat to turn it off as well. 

Turn off ignition by switching off the row of magneto switches on the lower part of the instrument panel. 

Switch off the fuel supply by setting the wheel-shaped fuel selectors on your right-hand side cockpit wall to off. 

Engine Limits:

Power settings:

Take-off on 100 octane fuel (long range load - up to 14500lbs - select outer fuel tanks), up to 800-1000ft or for two minutes using max RPM at max boost (boost cut-out on): +9 psi boost, 2750RPM 

Take-off on 87 octane fuel (normal load - up to 12500lbs - select inboard fuel tanks, outboard tanks empty), up to 1000ft or for three minutes: +5 psi boost, 2050-2650 RPM 

Climb: +5 psi boost, 2650 RPM 

Maximum cruise on rich mixture: +3.5 psi boost, 2400 RPM 

Economy cruise on lean mixture: +1.5 psi boost, 2400 RPM 

Maximum level flight power (5 minute limit): +5 psi boost, 2750 RPM 

Maximum Dive (20 seconds limit): +5psi boost, 3100 RPM 

Oil Pressure:

Normal: 80 psi 

Emergency minimum (5 minute limit): 65 psi 

Temperatures:

Oil Inlet Temperature:

Minimum for opening up throttle: 5 degrees 

Maximum for continuous cruising: 70 degrees 

Maximum for climbing: 80 degrees 

Emergency maximum (5 minute limit): 85 degrees 

Cylinder Head Temperature:

Maximum climb: 200 degrees 

Maximum cruise: 180 degrees 

Maximum level (5 minute limit): 240 degrees 

Continued by K-9: 

additional info:

Takeoff at full fine pitch. I don't know if the sim models the different fuel in the outboard tanks. The real life drill is to select outboard tanks, set the boost cut-out to on and give it +9 lbs boost while doing what is by now common knowledge to keep it from veering to the right (brake and left rudder to force left wheel braking, more throttle on the starboard engine and less on the port one), until you get sufficient speed that your rudder becomes effective.

In one of Freycinet's videos you can also see a different method. He only gives it about 60% throttle which lessens the drifting to the right, until the airspeed rises and the rudder is again effective.

Then you can advance both throttles to full, lay off the brakes and keep it going straight with the rudder.

Lift off at about 80-100mph but don't climb. Retract gear and disable the boost cut out (which lowers your maximum boost to +5 lbs) to keep your engines healthy.

Once you reach 120mph go to coarse pitch (pull the pitch levers all the way back, anything above that qualifies as fine pitch so if you just set it to 50% of the way you're still running full fine and high RPM).

Once you reach 150mph you can start climbing. Max climb is +5 lbs and about 2600-2700 RPM (going from memory here) but i don't know how the in-game CEM agrees with that. In any case, even the manual recommends climbing at lower settings for economy reasons so it should be perfectly possible.

Max continuous is +1.5 lbs for lean mixture and +3.5 (if i'm not mistaken) for rich mixture. Once again, mixture is either auto lean or auto rich, there are no in-betweens. In this case however the full-range motion of the levers is historically correct, you just set them according to the demarcation labels on the throttle quadrant. Lean is with the levers forward and rich is with the levers back.

To cut a long story short, as soon as you lift off raise your gear, level out, go to coarse pitch once you hit 120mph, disable the boost cut-out and throttle back to +3.5 lbs boost. When you hit 150 mph trim it for climb, start monitoring your engine temps (you might need to close the cowl flaps a bit, this will also give you some more speed and a better climb) and give yourself a pat on the back.

You might also want to switch to the inboard tanks once you're established in the climb, just to start learning good habits for when the different fuel is modeled (if it's not already). Another reason for this is that only the outboard tanks have the ability to jettison fuel (again, i haven't tested if this is modeled in the sim), so it makes sense to first burn the fuel you can't dump in an emergency during cruise to maximize on saving weight in such a case.

Once you reach your chosen cruising altitude and trim for level flight, throttle back to +1.5 lbs boost and set mixture to auto lean (levers full forward) to maximize your fuel economy.