Hartzell Trailblazer prop for the BH5 IO-540 290hp

[N204jh]

I'm struggling with my prop decision and would appreciate the experience of the forum. For my BH5, I got an Airworx IO-540-D4A5 with 9:1 cylinders, oil squirters, and I'm using a System 32 EFII. I'm hoping to get 290-295hp out of the combo. I'm running 8:50 tires for a 100 hrs or so until I get my real backcountry chops up to par, and then will switch back and forth with 29" tires depending on mission.

The question is what Hartzell Trailblazer 3 bladed prop to buy: 80", 82", or 85" blades. Virgil sells the 80" and 85" in a package bundle and Virgil recommends 85" for better cruise but only for larger tires than 8:50's. The 85" also are right at the very high end of tip speeds, so are screaming on the ground.

What did you choose and recommend? Also, is buying direct from Hartzell the best choice, if I don't buy the 85" package from Virgil? Or did you buy from somewhere else?

I have gone over the Hartzell standard application guide and it lists the 82" and 85" as options for the various 300+hp IO-540. The 80" is only listed for 2 blades and IO-360 / 390's.

Thanks much!

[rodsmith]

Seems like the 82" would be the sweet spot. Have you looked at Catto props, I know Virgil sells them, I have no idea how they compare to the Trailbrazer. I have an 82 5/8" 3 blade MT on my 300HP engine. At 2700 rpm the tips are in the transonic range (greater than 92% speed of sound). One neighbor complains about the noise, others think it sounds cool. Faster tip speeds get much louder and less efficient quickly as tips approach the speed of sound,

[gregc]

There is a C180 near me that runs a 300+ HP engine with a seaplane prop (not sure how long). The plane generates a tremendous amount of noise. His take-off climb appears to be significantly poorer than another local C180 with a stock O-470 and a reasonable length Trailblazer.

[N204jh]

Virgil is testing the new Catto 3-bladed prop and it's flying on a few Bearhawks, but Virgil said he wanted to get some more hours on the prop before he sells them or recommends the new version. He said hopefully before the end of the year. He also said he's hard to beat the Hartzell Trailblazer prop.

So, Rod, are you happy with the MT 82" 3 bladed prop, besides the takeoff noise?

[Astro John]

If noise is a concern, you could always think about using reduced power and RPM for takeoff when it’s appropriate.

[Nev]

Mine is 82" 3 blade trailblazer on 260hp IO540. Very happy with it. I'm on 29" bushwheels. Ground clearance is fine. Others report that it is quieter than other similar aircraft, but it does still have a decent sound signature on takeoff. I always reduce rpm as soon as I'm airborne.