RFDS Western Australia - modifying PC-12's with 5 blade props

[Office Update]

November 11, 2020,
from: AIN online

Royal Flying Doctor Service (RFDS) in Western Australia is upgrading its fleet of Pilatus PC-12 turboprop singles with Hartzell 105-inch-diameter, five-blade composite propellers. The new propellers will replace the existing Hartzell four-blade aluminum propellers on the utility aircraft that the RFDS uses for medical emergencies and patient transfers. Last year the RFDS fleet transported 9,012 patients over 8 million kilometers (4.97 million miles) across Western Australia, reaching some of its most remote corners.

RFDS already has three PC-12s in service with the five-blade propellers installed at the Pilatus factory and two more are undergoing installation at RFDS’s maintenance base in Jandakot. The operator further has three more on order, and RFDS Western Operations managing engineer Andy Lewis said plans call to upgrade its entire fleet of 16 PC-12s. West Coast Propeller, Hartzell’s recommended service facility in Western Australia, is supporting the conversion.

"The new Hartzell propellers are lighter, stronger, require less maintenance, and provide more torque, which enables the aircraft to fly better and ultimately save on fuel," Lewis said, adding they will also reduce vibration, increasing patient comfort.

"The five-blade composite swept-tip props chosen by the RFDS are specially designed to maximize performance for the Pilatus PC-12," added Hartzell Propeller president JJ Frigge. "The prop is a product of Hartzell's multimillion-dollar investment in structural composites, advanced aerodynamics, and modern manufacturing processes."

[Pettibone]

https://hartzellprop.com/hartzell-introduces-5-blade-carbon-fiber-propellers-for-pc-12-fleet/

[Section28- BE]

Shouldn't, do know that- 'Field Repair' approval.....?????, or pull the Blade on-site....???

Just a question.
rgds
S28- BE

[havick]

Shouldn't, do know that- 'Field Repair' approval.....?????, or pull the Blade on-site....???

Just a question.
rgds
S28- BE

Why field approval? Pretty sure it’s just an STC.

[Office Update]

Bolt the new prop on to engine.
Insert STC into AFM and review any Operational Limitations.
Good advice to suggest conducting 'dynamic prop balance'
Sell old props to other RFDS divisions or Ebay

Easy easy!

[Kiwiconehead]

How do the composite props hold up on dirt?

[Switchbait]

How do the composite props hold up on dirt?

You need to keep a few tubes of Araldite handy...

[Kiwiconehead]

You need to keep a few tubes of Araldite handy...

Same as the Dowty props on the Q400 then

[Section28- BE]

You need to keep a few tubes of Araldite handy...

Righteo then, gotya!!! Ta- assume, the 5x minute/300 second variety- link here: https://www.selleys.com.au/products/adhesives/heavy-duty-repairs/selleys-araldite-5-minute/

Given, The Mission and Contingent Risk/Liability Study and then Compliance etc. ....- then also, the 'Busted Ringer' on the stretcher/ or the 'busted' Appendix....

Mr Hartzell link here, ALL Good: https://hartzellprop.com/services/overhaul-and-repair-services/composite-repair-videos/

Thanks all- got 'it' now....!!!!
Sorry to interrupt.
rgds
S28- BE

[Desert Flower]

Several of the YPAD based PC-12's have the 5 blade props.

DF.

[Global Aviator]

No one has mentioned what I consider a very important reason.

How good do they look!

:E

[atakacs]

Is it the NGX propeller or something different ?

[0ttoL]

I'm guessing that better ground clearance is also a factor?

[Blueskymine]

Doesn’t matter how many blades your prop has when you only have one engine.

[Captain Nomad]

Both the 4 blade aluminium and the 5 blade composite props on the PC12 are 105" diameter so no real change to prop clearance...

The composite props have a steel leading edge strip so it would take a lot more effort to damage them than the aluminium ones... I doubt RFDS would be running them unless they had proven that they hold up well on the dirt strips.

[machtuk]

They better be good cause at $85K or so per prop that's a LOT of donation dollars!

[Switchbait]

Same as the Dowty props on the Q400 then

I assume so. It’s how we filled the dings in the EMB120 props too

[0ttoL]

Both the 4 blade aluminium and the 5 blade composite props on the PC12 are 105" diameter so no real change to prop clearance...

The composite props have a steel leading edge strip so it would take a lot more effort to damage them than the aluminium ones... I doubt RFDS would be running them unless they had proven that they hold up well on the dirt strips.

Great information. Thank You Captain!!

[bolthead]

I have it on good authority that you can pick the difference in performance. Not necessarily in a good way.

[rcoight]

I have it on good authority that you can pick the difference in performance. Not necessarily in a good way.

Really? I’ve got plenty of time behind both props and given the choice I’d take the five-blade every time.

Performance is much better during take-off / climb and it’s also noticeably smoother / less vibration.

[havick]

I have it on good authority that you can pick the difference in performance. Not necessarily in a good way.

Can you get a refund on your source/authority?

[Guptar]

MT now have a 7 blade prop that is EASA certified.

https://www.mt-propeller.com/en/entw/stcs/pilatus_3.htm

[merlin45]

I've got a small amount of time in the Pc with both props. In my experience the 5 blade has better T/O perf, quieter and marginally better climb perf. They were about the same cruise TAS for a given power setting. Not sure on the scheduled maintenance side of things but we did have some delamination issues with the 5 blade.

[compressor stall]

Really? I’ve got plenty of time behind both props and given the choice I’d take the five-blade every time.

Performance is much better during take-off / climb and it’s also noticeably smoother / less vibration.

Between this and the PC24 threads, you're sure racking up the kills. Keep it up :ok:

[rcoight]

Between this and the PC24 threads, you're sure racking up the kills. Keep it up :ok:

It’s all good. The only people I know who don’t like the 5-blade are engineers.

Maybe bolthead’s source is an engineer? :)

merlin45 is spot on with his/her assessment from the pilot’s perspective.

The first time I flew with the 5-blade was on takeoff from Switzerland to ferry a new one back to Oz.
After 4000 hours behind the 4-blade it felt like a totally different aircraft. There isn’t anything much in it in the cruise, but takeoff / initial climb is noticeably better. Much more thrust. Different sound too. Quite distinctive, but quieter and smoother.

Don’t know why anyone would prefer the old 4-blade, TBH.

[FGD135]

"The new Hartzell propellers are lighter, stronger, require less maintenance, and provide more torque ... "

"Provide more torque". LOL.

[FGD135]

Much more thrust.
Could that have been due to the colder Swiss temperatures, rather than the prop, rcoight? How do you know they provide "much more thrust"?

[Captain Nomad]

What's the snickering for FGD135? There are different cruise torque charts applicable to the 5 blader. I'll give you one guess as to which way the numbers go - might have something to do with the lighter weight...

[FGD135]

I'll give you one guess as to which way the numbers go ...
Higher torque? That could be because the new prop is turning more slowly than the original. What is the new prop RPM compared to the old?

Also, is it the same gearbox?

[rcoight]

Could that have been due to the colder Swiss temperatures, rather than the prop, rcoight? How do you know they provide "much more thrust"?

No. The temps in Switzerland when I was there were equivalent to or warmer than winter temps where I'm based.
Hard to believe, but it wasn't a non-stop flight Switzerland to Oz. During that trip I also departed from Egypt / Dubai / Myanmar / Delhi / KL all with temps around 40C or above. Noticeably better take-off / climb performance every time.

Since then I've flown around 1000 hours behind the 5-blade, as well as another 1000 behind the 4-blade. Sometimes on the same day.
No comparison. The 5-blade produces superior performance (except in cruise), and is quieter and smoother.

The comment "much more thrust" is a seat of the pants feeling backed up by actual performance numbers.
I would have thought that was obvious.

The 5-blade turns at the same 1700rpm in all phases of flight as the 4-blade, BTW.

[Capn Rex Havoc]

Perhaps the aerodynamics of the the blades produce more thrust than the conventional blades. Blade shape would affect thrust. Thats how you get more thrust out of the new prop.

[megan]

The enhanced performance seen with the new prop is not unusual, it's the exact same reason that other aircraft that have been given the same treatment, even your humble GA piston.

https://www.emerald.com/insight/content/doi/10.1108/aeat.2002.12774cad.015/full/html

[rcoight]

The enhanced performance seen with the new prop is not unusual, it's the exact same reason that other aircraft that have been given the same treatment, even your humble GA piston.

https://www.emerald.com/insight/content/doi/10.1108/aeat.2002.12774cad.015/full/html

Exactly. It's hardly a new thing.

Replacing one prop with another with more blades to enhance take-off and climb performance and reduce noise / vibration has been going on for decades.

[FGD135]

Thanks, rcoight.

The 5-blade produces superior performance (except in cruise) ...Please elaborate on how the cruise performance is not superior to the original prop.

Are you referring to cruise scenarios where the engine power is set at a torque limit, an ITT limit, or neither? If a TQ limit, are these limits increased or decreased, compared to the original prop? If using a recommended cruise power setting (neither a TQ nor ITT limit), then how does the TQ value compare to the original?

Did the AFM get new tables for takeoff performance? Climb performance? Cruise performance?

Apologies for the large number of questions.

Thanks again.

[megan]

Don't know the science behind it, but the new props certified for a whole range of aircraft always improve the take off and climb performance but not the cruise.

[Sunfish]

Thrust reduces with airspeed. That might have something to do with it.

[Global Aviator]

I’m disappointed that no one agrees with me that the ascetics of more props is certainly a good reason! :ok:

Ok, that only my opinion.

Think my first love of more props was when I first saw the Panther Chieftain!

[Capt Fathom]

I doubt aesthetics come into it when the accountants get involved!

[rcoight]

I’m disappointed that no one agrees with me that the ascetics of more props is certainly a good reason! :ok:

I certainly agree. 5-blade prop looks nicer.

FGD135 You’ve given me a fair bit of homework. I’ll answer soon, unless others want to pipe up with the answers first.

I don’t have an engineering bone in my body so can only answer from my own experience flying the relevant aircraft.
The five-blade may be worth a few knots in the cruise (not sure what the FM claims without checking), but if it is it’s barely noticeable.
The highest cruise TAS I’ve ever seen in a -12 was with the 5-blade, but I’m not convinced other variables weren’t more at play than the prop.

However, the takeoff and climb performance is unquestionably better with the 5-blade.

[Checkboard]

Think my first love of more props was when I first saw the Panther Chieftain!


https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/602x321/index_a2a86f7dd47496e5cb6437c60b8d560e9a1fb170.png

[megan]

One blade more is better Checkers, no torque to worry about.

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/800x400/1606100969_979075873d9080afbfd688915219526960edda18.jpeg

As Sunny mentions, thrust reduces with airspeed in accordance with the formula,

Thrust = BHP*325/Airspeed(kts)

Thinking out aloud, perhaps the increase in prop solidity with the extra blade allows the thrust to be produced at a lower blade CL and thus reduced induced drag, more of the TQ going to thrust rather than being lost to drag.

The prop manufacturer for the new PC-12 5 blader (MT) cite,

Ground roll distance reduced by approx. 15%
Take-off distance over 50 ft obstacle reduced by approx. 5%
Climb performance improved
Cruise performance improved by up to 5 kts
versus the PC-12 POH/AFM

[atakacs]

I asked previously without success...

Is that the propeller of the NGX or something different for earlier airframes ?

[rcoight]

I asked previously without success...

Is that the propeller of the NGX or something different for earlier airframes ?

I am referring to the 5-blade prop which has been available on factory new PC-12s since around 2017.
It may or may not be the same as the one on the NGX.

[megan]

Is that the propeller of the NGX or something different for earlier airframesThe NGX seems to be a marketing designation, the TCDS designation is PC-12/47E MSN 1720, MSN 2001 and subsequent, fitted with a Hartzell 5-Blade Composite Propeller.

The previous 47E MSN 1576 up to 1944 are fitted with the same Hartzell 5-Blade Composite Propeller (Hartzell HC-E5A-3A/ NC10245B).

Still earlier 47E were fitted with four blade aluminium Hartzell , MSN 545, 1001 to 1575

https://www.easa.europa.eu/sites/default/files/dfu/TCDS_EASA_A_089_PC-12-Series_i9%20%283%29.pdf

[flightleader]

7 blades make it looks like a star nosed mole:}