Which Prop

[osxuser]

Why did he shed part of the blade though?

[N941WR]

The NTSB said it was fatigue. No nick was noticeable on the prop stub. Apparently those solid Curtis-Reed props where known for doing that.

Eddie said he was looking over the side of the plane, felt a vibration, pulled the throttle back, looked up and noticed the cylinders were no longer visible and he was going down at a FAST rate. That was all the warning he had. Oh, he also had news (video) footage taken as they were standing around talking to the authorities. In the back ground was the plane with the engine hanging there and all of a sudden it just fell off.

Man, was he ever lucky!

I can't wait to finish the -9 so I can take him for a ride, what a great mentor he was. I learned so much from him! He has since sold this Waco UPF-7 (after he got it back in the air), his Stearman, Travelair 4000, J-3, and T-6 (Yes, he owned all five at the same time.) and bought a BIG sail boat, rented his house and retired to the Bahamas with his very lovely wife Elaine. Since he never flew the J-3 he gave me a key to the hanger and let me fly it whenever I wanted, even insisted I didn't top it off. What a great guy!

[praterdj]

Caution.....In the RVator article it mentioned that the pilot would not feel most of the harmonic vibrations and that over time it caused fatigue in the prop blades.

I'm not sure it's safe to assume that just because you don't feel it that it isn't happening. I personally think that the limitations are there for a reason. Certainly there is a safety factor built in but I don't plan to go against it. JMHO.

[lesdoud]

All,

I would like to clarify some info here. I offer this info as an engineer (I'm not a salesman) and I'm building an RV myself...

Dan is correct, the new "BA" 7497 prop is approved on the 200 Hp IO-360-( )1( ) series engines with the restriction he listed. However, although it is not listed on our TCDS yet, it is approved on the damped crankshaft -A()B6 series engines also, without any placards (read NO PLACARDS on the damped crank engines). It is also approved on the IO-390-X engine with NO PLACARDS (all -390s must have dampers according to Lycoming).

It is currently available at 74" diameter and will be available at 72" soon.

I respectfully disagree with anyone that suggests that you can ignore engine-propeller vibration approval, or restrictions and placards regarding engine-propeller compatibility.

Les Doud
Propeller Integration Engineer
Hartzell Propeller Inc.

[dan]

Originally Posted by lesdoud

Dan is correct, the new "BA" 7497 prop is approved on the 200 Hp IO-360-( )1( ) series engines with the restriction he listed. However, although it is not listed on our TCDS yet, it is approved on the damped crankshaft -A()B6 series engines also, without any placards (read NO PLACARDS on the damped crank engines). It is also approved on the IO-390-X engine with NO PLACARDS (all -390s must have dampers according to Lycoming).

Thanks for the clarification, Les. That's great news.

[osxuser]

Originally Posted by lesdoud

All,

I would like to clarify some info here. I offer this info as an engineer (I'm not a salesman) and I'm building an RV myself...

Dan is correct, the new "BA" 7497 prop is approved on the 200 Hp IO-360-( )1( ) series engines with the restriction he listed. However, although it is not listed on our TCDS yet, it is approved on the damped crankshaft -A()B6 series engines also, without any placards (read NO PLACARDS on the damped crank engines). It is also approved on the IO-390-X engine with NO PLACARDS (all -390s must have dampers according to Lycoming).

It is currently available at 74" diameter and will be available at 72" soon.

I respectfully disagree with anyone that suggests that you can ignore engine-propeller vibration approval, or restrictions and placards regarding engine-propeller compatibility.

Les Doud
Propeller Integration Engineer
Hartzell Propeller Inc.

Can't blame you for that one (given who you work for especially). And I can't say that I thought my opinion would be recieved very positively in general (hence the multiple disclaimers...) But I have seen a ton of cut-down, weird application, not placarded, etc etc... props that fly for thousands of hours with no problems. Most homebuilts don't have the advantage of being so prolific that a prop company will actually do a vibe analysis for them specifically.

I do suggest that the TBO be followed closely (6 years for most Harztells), so if fatigue does become a factor, it can be detected.

[gh6gh6]

At OSH this year a Hartzell rep told me they are close to starting the engine testing on composite blades with the blended airfoil. He said they would be substantially lighter and they would start approving them for use with the most popular engines.

Price would be comparable to the Aero Composite Prop.

Anyone else hear anything about this?

Ian
RV7 QB
Wings

[lesdoud]

All,

Yes, Hartzell announced the new composite blades at Oshkosh this year.

The new composite blade was designed for a 3-blade assembly intended for 300 Hp applications, thus the new prop on the SR-22. However, the analysis I did showed it may work well in a 2-blade configuration on an IO-360 (from a performance standpoint). Unfortunately, we've not tested it yet on those engines. Because the aluminum -360 blades we have approved are relatively heavy (for a reason), the weight savings on those applications may be worth the effort. Right now, the weight savings it offers compared to a typical 3-blade on six-cylinder engines is approximately 12 lbs. The weight savings compared to a 2-blade -360 prop may be similar, approximately 10-12 lbs, with a potential total weight of approximately 47 lbs (not including spinner). As I said, we haven't tested it yet so I don't know how it will work from a vibration perspective.

We are always trying to improve our products for this market, trying to design-in more performance with this lowest weight possible but still comply with the Hartzell service history standards, thus the 7496 for the 180 Hp, and the slightly heavier 7497 for the 200 Hp engines. It isn't easy and costs a lot. The ASCII may be the next step, but its too early to tell. One of the things our marketing/sales guys factor-in is how many props they can sell to justify the costs of the approval process. I don't think anybody at work knows how many homebuilders would buy a new ACSII? I suppose that depends on price? What do you think the market price-point is for a new Hartzell composite prop? The new composite prop costs more than an aluminum prop to manufacture so it will be higher, no doubt, but it might be too high to justify a program just for this market. In that case we'll have to wait until OEM and STC applications cover us.

The bottom line is its too early to know if we can approve the ACSII on the 360 engine, especially since they come in so many flavors, 180 Hp, 200 Hp, damped crank, undamped crank, LSE, LASAR, FADEC, Superior, ECI, high CR pistons, etc,; there is at least three vibration surveys to accomplish. Only time and market demand will determine if and when we can offer the ACSII to you all.

Les Doud
Propeller Integration Engineer
Hartzell Propeller Inc.

[dan]

Les,

I just want to say thanks for monitoring these forums and posting the info you did. It's terrific having folks representing mfrs to keep us in line, make sure we're speaking the truth, and give us insight into "real" developments. Your input is highly valued...so thanks.

[JohnR]

Ditto waht Dan said above. Thanks for the input. It is very helpful.