Spit Mk1 Boost?

[Robo.]

Originally Posted by SEE

If I fly straight and level - full throttle, with the boost cut out positioned for that extra bit of throttle movement - I don't see any increase in RPM, IAS, etc. That left me wondering what should I expect to read on my gauge at 18000ft for example and what performance gains I should expect to see or get.

At 18000ft, the gain with BCC-O enabled was rather marginal afik.

Enabling the boost on the ground (sea level) for example, would increase the Boost (manifold pressure) from +6.25PSI to +12PSI resulting in extra 270hp (cca) coming from your engine for the price of rising water temperature (obviously), engine wear etc (hence the restricted usage). The Boost would then consequently drop with rising altitude as per normal - exact figures depending on the given atmospheric conditions. The gain was most noticable down low, I can try to dig out approximate figures if needed.

Almost double boost didn't mean double power mind you, the 3000RPM limit was still to be considered.

What you expect to happen when ''you pull the plug''? At sea level - you can see the boost gauge reading above the +8PSI limit, you can feel and hear the engine working harder, you can see the water temp rising faster, RPM very much depending on the type of propeller used - but your Merlin III is giving you extra 270hp with all consequences.

Hope that helped.