Classic British Flight Sim

Observing the HS-748 on takeoff with and without water methanol has given me the conclusion that there is no change in performance other than keeping the engines and fuel cool for longer. However upon researching I came across documents with tables for all RR Dart engines. It states for the 748-2A's Dart Mk.534-2:

Take-off power without W/M injection; 1368kW.
Take-off power with W/M injection; 1521kW.

That's an 11% increase in power.
I was thinking, would it be possible to modify the water methanol gauges so that when they're switched on, the thrust scalar = 1.11?

I am also wanting to add the engine smoke from DM's 1-11 to the HS-748, but only when water methanol is on, as my experience of water methanol is it gives one hell of a smoky trail. Could the water methanol gauge be a switch for that too?

The power increase is kind of a red herring. Yes, the engine can produce more power, but that's because your limiting factor on the engine is temperature, not RPM. By injecting the water, while it does make the air more dense, its primary function is cooling the air which allows you to achieve higher RPM for the same temp, thus increasing power. In actual operation, water injection was simply used to maintain rated takeoff power to a higher ambient temperature, not actually provide more power.

Spot on Chris!

As to adding smoke, I've never seen a smokey Andover, even whilst conduction engine runs with Water Meth on.
Here's a poser for you Dart engine types:

How did they 'clean' the Darts? I don't mean with soap and water either.

Hmm so really on longer runways and lower weights I should just take off with less throttle e.i. Climb power?

All Dart powered aircraft use full power, trimmed to ambient, for takeoff. The primary reason being to enable the autofeather system to operate if necessary.

Cheers

Fraser

But on low payloads the bloody thing takes off too fast for me to think! Haha! It's like rotate, gear up, flaps up, power down straight away haha

Scorpius wrote:Spot on Chris!

As to adding smoke, I've never seen a smokey Andover, even whilst conduction engine runs with Water Meth on.
Here's a poser for you Dart engine types:

How did they 'clean' the Darts? I don't mean with soap and water either.

You mean with the crushed Walnut shells?

Yes I'm a Dart type...Fokker 27 to be exact.

Ttfn

Pete

Viscount Cornbank wrote:All Dart powered aircraft use full power, trimmed to ambient, for takeoff. The primary reason being to enable the autofeather system to operate if necessary.

Cheers

Fraser

Yes , but you could apply a downrate by trimming for a higher ambient temp than actually present,
provided you could make first segment climb out at single engine safety speed. Autofeather would still work, being based on the gearbox torque pressure iirc.

Ttfn

Pete

Correct answer Pete! I thought the Oily's were taking the p*ss when they first told me. Not much good for washing up though.

Nev