Hello
What are our objectives for the PROP STC?
The following lays out what our intent is.
ENVIRONMENTAL IMPACT MITIGATION
Reduced fuel burn = ....
A reduction in fuel burn to achieve a task is a step towards NetZero2050 obligations. This is our bit towards:
- Environmental impact mitigation,
- lower CO2,
- lower NOx, and
- lower H2O emissions (yes, turbo prop aircraft are not notable as a cause of contrails, not like the days of World War 2 where B-17's.Mustangs, Messerschmitts and others traced a global conflict against the sky)
- reduced demand on HC fuels
COST SAVINGS
Cost reductions
Improved performance of propulsion provides a lower cost from:
- Fuel burn saving
- lower loads on your engine
- lower low frequency stress on the propeller, gearbox and engine power transfer/torque meter shaft
- reduced EGT/ITT, lower erosion to the turbine aero components,
- for free turbines (and turbofan engines) lower power section operating RPM giving lower blade elongation and wear.
- Lower loads to the gear box, torque input to an RGB is reduced for a given thrust from the propeller.
Reliability
- Meet performance requirements with more EGT/ITT margin.
- Lower loads, increased reliability
- Overhaul, get closer to TBO or make MORE with increased likelihood.
Performance!
What do we add for performance?
The propeller is part of the propulsion system and it is necessary to respect the design limits of the original certified design. This means that while we can get more thrust, we end up limiting that to the original thrust in most cases, for sea level operations up to the limiting critical temperature. So, for down low in Antarctica, no more thrust please.
Above about 2,000ft altitude however, more thrust is possible, but it comes with caveats:
- More thrust at low speed increases minimum control speeds, by approximately 1/2 of the thrust change percentage.... 20% more thrust, V speeds increase by 10%.
- Increased thrust comes by taking up some of the EGT/ITT margin that you are being blessed with, and that removes the benefit in maintenance costs and safety of having greater margins.
It is possible to climb faster, higher and cruise faster, all of which would occur with a reduction in the benefit that is being provided for safety and reliability.
Longer range is always going to be available, alternatively, a greater payload for a given range.