I’m careful when it comes to upgrading my aircraft. Enhancements have to “earn” their way onto the ship by providing increased range, speed, payload, capability, or safety.
Our Beechcraft King Air C90, LJ-1868, was due for a phase inspection in February, including the 5-year items and a mandatory propeller overhaul. That was the perfect time to opt for the Raisbeck swept propellers. I had to spend $15K to overhaul, which softened the blow of the upgrade, $90K (ouch).
Why upgrade? Two factors swayed me. I expected the swept props to be quieter, they are six inches larger in diameter, and are a few pounds lighter. Larger props meant more thrust and I was pretty sure that would result in increased performance.
My $75K bet paid off. I’ve got about 20 hours on the new props. Here’s what I found:
The thrust is so strong that the brakes can’t hold if you try to do a full power T/O holding the brakes. Acceleration on T/O is significantly harder but you also have to rotate at a higher speed. I use 95 KIAS since VMc is increased to 91KIAS. All in all, the airplane uses little less runway (my guess is about 200-300 feet less).
Climb performance increased greatly! 2000F/M+ up to 16000 and the 1500F/M up to FL200 and 1000F/M to FL270 ISA+10 (all at 9800lbs or heavier and 150KIAS/.31 Mach). I never exceed 98% N1 so the ship could climb harder up at altitude.
Cruise down low is really fast! Up against the barber pole (or faster) from SL to 14000. Up high about a 3-5KT increase.
A bigger prop means more deceleration at idle and in beta. Stopping distances are significantly shorter. I haven’t determined actual distances but I can turn off early without hard braking. I did have to adjust power settings to fly approaches at 120KIAS, about a 100ftlb reduction. I also leave a tiny bit of power in until flare. Like I said, the plane slows down fast at idle.
The props are very quiet up at altitude. They are perhaps half as loud as standard props. Down low there isn’t much of a difference since they also push more air. They sound different.
For all of the folks that appreciate form over function, I will also admit they look cool.
*Disclaimer: This review and testimonial is strictly on behalf of the author. Raisbeck Engineering did not solicit or request the review.
For any additional details about Jamie’s review, shoot us a note at info@kingairnation.com. For more information on Raisbeck or the Swept Blade Propellers, contact Scott Keefe at 206-723-2000 or www.raisbeck.com.
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About the Author: Jamie Lecker
Owner at ATI Engineering Services, which specializes in FAA certified modifications of special mission aircraft for both fixed and rotary wing. Flying for business. 2500 hours total time. Private pilot.