Blenheim take off

[Blackdog_kt]

Originally Posted by meplay

Hi Seeker, the only thing i do is basically have my right engine throttle at 100% and left at around 50% and as my back wheel starts to come up i set the left engine to 100% also. The main thing that stops me from overheating though is when ive started to roll quit fast, i start to drop the prop pitch slowly till its about half way or lower and thats seem to be the only thing that stop my CHT from sky rocketing through the roof.

Actually setting prop pitch to 50% has no effect. It uses two-stage props like the Spit.MkI but the sliders don't "snap" into the top and bottom position like they should. If you set pitch full back it goes to the low RPM position, if you set it at anything higher than that it's the same as running it full fine.

Which means that running with the slider at 50% has no real effect, you can take-off just fine with it at 100% and save yourself some trouble


As for the temperatures now, i too had a bit of trouble. I could take-off just fine with an accelerated warm-up if i'm not carrying bombs, i would advance the throttles in a series of steps with the brakes on in order to "force" a temp increase. When they are running rough the aircraft shakes, when the shaking stops you know it's sufficiently warmed up for the current boost setting so you push it up a notch or two.

However, i would only get the CHT (cylinder head temp) to 150 or so and upon trying to take-off with a bombload bad things would happen. If its unloaded you get enough acceleration and rudder authority even with the engines running slightly rough, but if it's loaded the acceleration is slower, airflow is less and engine components start to fail.

My most recent trick is frequent use of the cowl flaps to actively control CHT. This is also really critical during descent and approach/landing. You can't just chop the throttle and start descending at high speed, the engines will go cold and by the time you deploy gear and flaps and need the extra power for the flare and touchdown you don't get any.

In fact, the entire profile of the approach (how low can you set boost and how fast you can go in combination with your cowl flaps and prop pitch setting) is determined by keeping the temps where they need to be.

If you just put the nose down at coarse pitch (which will cause you to accelerate even further) and chop the throttle you're about to suffer.

Instead, chop the throttles first and go to fine pitch (high RPM), this combination makes the props windmill almost face-on to the incoming airflow and acts like an airbrake. Then start closing cowl flaps (i had them at about 30%-40% and it was still resulting in too low CHT), but remember to open them again when you re-apply throttle to settle into the glide slope.

Yes, it's difficult and the ergonomics in the cockpit are not really the best, but it's highly realistic. Similar things happen with most radial engines, you can take a look on youtube at the A2A P-47 for FSX, or even better, search for some videos showing DeHavilland Beaver aircraft in Canada or Alaska starting up their wasp junior engine.

Radials need some pretty intensive temp management, this workload is the trade-off for their reliability, power and combat resilience.