The reality is, comparing these two propeller sets (the factory Hartzell 4-prop and the MT Whisper Prop 5-prop) is apples to oranges.  

Noise (take-off):B1900C:Hartzell 4-blade: 84.0dBMT WP 5-blade: 81.5dB2.5 dB difference1900D:Hartzell 4-blade: 88.0dBMT WP 5-blade: 83.0dB5.0 dB difference  Keeping in mind that decibels are measured logarithmically, where 3dB represents a 50% reduction in sound pressure level, a drop of 5.0dB is a significant reduction in noise. You can find this data in EASA’s public record, ICAO Annex 16 section 10.4(a) for take-off noise. I’d be happy to provide you a copy if needed. 

Direct Operating Cost Savings: 
Because the core of the MT blade is the structural component made of composite (resin-infused beechwood), it never needs to be replaced for fatigue damage, giving it unlimited blade life. These blades will be the last blades you’ll need to purchase for this aircraft. In addition, overhauling will always bring blades back to full factory dimensions.Comparing that to your next Hartzell blade replacement:  

Service Schedules:
Hartzell 4-prop: 4000hrs/72 monthsMT WP 5-prop: 4500hrs/72 monthsIndustry best overhaul schedule  
 Shorter Blade Diameter:
 results in less runway FOD damage to the blades, engines and structure, as well as quieter cockpit noise and vibration.1900C & D: (278.1cm to 260cm)                
No RPM ground limitation: 
The Hartzell 4-blade prop system induces a critical and destructive vibration condition to the aircraft while on the ground, requiring a ground idle solenoid to keep ground idle above a certain threshold. The MT five-blade replacement does not have this problem, therefore allowing deactivation of the ground idle solenoid when MT props are installed. Much quieter taxiing in your future!  
Toughest blade available: 
Composite hardwood core and nickel-cobalt leading edge result in industry best damage and erosion protection.
 Field repairable blades: 
Most FOD damage can be simply repaired shipside with the blade on the aircraft using minimal tools and 5-min curing epoxy, if desired. This allows for unlimited replacement of blade OML (exterior factory shape). This is especially attractive on high-FOD runways. Hub replacements are not necessary as with metal props, simply swap blades and fly – only dynamic rebalancing needed. Also, in-field replacement of blades are possible without rebalancing, providing operators with industry best Return To Service  
Interchangeable blades: 
The MT 1900C and 1900D blades use the same blade part number and can be swapped out in the field with simple dynamic rebalancing. The Hartzell blades cannot be interchanged between aircraft type. 
Lower maintenance cost :
Unlimited service life, interchangeable blades, additional time between TBOs, significantly reduced repair downtime and less fatigue vibration on aircraft structure and instrumentation all point to substantially reduced cost of maintenance.  
Direct Pilot Feedback from North American Program Launch Customer: 

Chief pilot notes/quote after flying MT prop upgrade:             
 Cruise performance differences At altitudes in the FL220 to FL250 range at the same Torque setting, N1 is 4% to 5% lower At altitudes below FL200 at the same Torque setting, N1 is 6% to 8% lower Pilots report that takeoff acceleration is noticeably better Pilots report that initial climb when speed is set to Vy (best rate of climb speed) that the climb rate is much better. When speed is set to cruise climb rate of climb is a little lower that 4 blade Hartzell props During cruise at same speeds fuel burn is 20 lbs per hour lower

AMK will work a program that will fit your needs
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