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Review: The Hartzell Composite Propellor on my RV-7A

Hartstoc

Well Known Member
Not long after I purchased my flying 7A in October of 2017, I took the plunge and ordered a Hartzell Composite propellor and aluminum spinner through Van’s. The decision to buy was downright scary, as several pleas for opinions and experiences here on VAF went unanswered, and searches of prior posts turned up very little info. Were pilots having bad experiences they were not revealing? Was I making an expensive mistake?

The blades have an incredibly large surface area and chord widths from 3.5” at the squared-off tip to over 8” at the widest point. Long after I’d paid, my old friend and propellor guru Jack Norris told me that classical propellor theory would suggest nasty tip vortices, and I wondered if my plain-vanilla 180HP, 8.5 compression Lycoming clone would be able to pull it, or if top speed would be severely limited. I’ll jump ahead and declare a resounding YES to the first and NO to the second. Evidently the lack of info on VAF was mainly due to very few of these being installed on RV’s because of the higher cost.

The only assurance I got was from potentially biased sources. Hartzell tech support told me it WAS a good match, that there were sound reasons for the 8”+ max chord, that I could expect fully 100 pounds more static thrust with my engine than the aluminum Hartzell BA could generate, and that there were absolutely no RPM restrictions or blade-life limitations. I also talked to Mike Stewart, lead pilot for “Team Aerodynamix”, which Hartzell had sponsored to install them on all of their RV’s. He said that they may have lost perhaps a knot of top speed compared with the aluminum Hartzell, but that the other advantages completely outweighed this. I was also encouraged to learn that this is the same blade(with 1” lopped off)offered as an optional threesome for the 300 HP Cirrus SR-22. That sled does not enjoy quite the same speeds as our RV’s, but it is in the same ballpark and has about the same power loading per blade area.

I promised myself I’d post a thread describing my own experiences with this beast for the benefit of others. I’ve not had a chance to do much in the way of controlled study of absolute performance, but I can relate my anecdotal experiences so far with about 50 hours including considerable aerobatics and cross country time. I’ll supplement this later as I acquire more real data.

2v2Ev48o4xBELK5.jpg


Additional photos of my installation can be found here, please be sure it is in “roll view” and do read the captions appended to each photo:
https://public.fotki.com/Hartstoc/hartzell-composite/?view=roll

The fixed pitch aluminum propellor I replaced on my bird was a Sensenich 72FM889-1-85, designed specifically for the 180 HP Lycoming variants. The last two digits refer to the pitch, 85” being the max available without re-pitching and the one Sensenich recommends for RV’s. It was actually a pretty good performer, producing brisk takeoff and climb and acceptably good cruise performance. I was actually tempted to have it re-pitched to 86” or so as I was unable to operate full throttle in cruise even at high altitude without over-reving the engine, and found myself cruising at an uncomfortable and noisy 2550 to 2650 RPM’s if I really wanted to cover some ground.

The entire Hartzell assembly including installed spinner weighs in at just under 44#, so I was “pleasantly shocked” to discover that the Sensenich assembly, including the 2” aluminum spacer, the stock Van’s spinner, and the long heavy bolts weighed in at fully 42.5 pounds! This was almost too good to be true, I’d be getting a huge performance boost with almost no weight penalty at the nose! My days flying numerous experimentals for the CAFE Foundation had taught me the deleterious importance of excess polar mass. In short, for any given airplane, polar mass(the “dumbell effect) is inversely proportional to maneuverability, ease of spin recovery, and fun. It is noteworthy that installing an aluminum Hartzell BA instead of the composite would have added 17# at this most forward station instead of what turned out to be a little over a pound!

Installation was pretty much a bolt-on affair, as Hartzell had generously created a hub just for RV’s that extended the blade-plane 1” forward, and an awesomely well built spinner with significant fore and aft positioning adjustability. Fortunately, my engine was set up for CS, so all I had to do is add a governor, an oil line, and a blue knob to make it work. I did have to remove a forward expansion plug from the crankshaft and install a smaller interference fit plug about 8” back to create the pressure chamber that drives prop pitch as described here in this Lycoming document:
https://public.fotki.com/Hartstoc/cs-prop-install-sb-1435/

I’ve never liked the propellor oil line installed on Lycomings, which contorts its way through hostile territory below the cylinders and is difficult to inspect. I was also disinclined to use a flexible oil line. I decided to fabricate and install my own heavy-wall stainless steel line routed much more favorably and fully visible during preflight. That story can be found in a somewhat contentious VAF thread that I posted. I respect the opinions expressed but absolutely stand behind my own design with great confidence. See:
http://www.vansairforce.com/community/showthread.php?t=160969&highlight=Governor+oil+line

Take-off and climb performance with the new prop installed is stunning, and I now understand why Sean Tucker calls the variants of it he has flown “the claw”. I set the RPM limit to 2720 RPM. About one second after reaching full throttle, the prop optimizes its “bite” and the acceleration is thrilling. My takeoff run is roughly half of what it was before- basically you apply power, pause briefly, and rotate. Sustained climbs solo with half-full tanks around 2,200 FPM are possible and I typically reach pattern altitude while still over a 3,000’ runway. I’m still exploring this and will report back later, but I seem to be getting max ROC at speeds well below Vx! I’ll leave it to the aerodynamicists to refute this possibility, but it feels like this thing has imparted a bit of helicopter mojo into my airplane! One advantage of the large, stiff, ultra-thin carbon fiber blades may by that they see far less flow separation along portions of their spans than do skinny and/or thick blades at some stations during high-power/low-airspeed operation. Also, cooling in climb is greatly improved. I think Hartzell has found a way to produce far more thrust with the inner third of the span than conventional propellors have ever managed, and some of that blasts right into the cooling inlets.

In cruise, and in concert with the new PCU5000 governor I installed, the prop is silky smooth, super stable, and very well behaved with no trace of hunting or oscillation. I generally feel that my engine and prop combo is happiest in the 2450-2500 range and well under square, but I tend to cruise at a bit more aggressive settings than many pilots seem to choose.

My very favorite thing about this prop, and I’m sure this is also true for the other composite CS props, is the impact of the very lightweight blades on nimbleness when doing aerobatics. Most of the weight is concentrated at the hub, so the reduction in gyroscopic inertial forces during abrupt maneuvers is profound. You don’t realize how much control force must be applied (at 90° to the desired change in direction!) to overcome the precession resulting from displacing a heavy aluminum propellor out of axis until you have flown lightweight blades. It really feels like a different airplane compared to the metal Sensenich.

One Big Giant Proviso! :

There is one thing that you must know and consider that is unique to this propellor: If you pull the throttle in flat pitch, it feels like a drogue chute has been deployed, and you are coming down fast with a best L/D of somewhere around 3:1! This is quite startling at first but I’ve come to regard it as an asset. On the flip side, with the blue knob pulled out, the thin-bladed prop goes to a very coarse pitch and, with the ultra-thin blades, the airplane feels more like a glider than most RV’s ever do. The big proviso is that it takes a LOT of oil pressure to hold the prop in coarse pitch, so to obtain it with a windmilling prop you MUST have a governor that can generate high pressure at reduced RPM, AND your installation must be relatively free of any oil leakage from the propellor pressure section into the crankcase. Mike Stewart admitted that his governor cannot do this, so if he has an engine failure with a windmilling prop, it goes to flat pitch and his landing site options will reside within a very small circle of real estate. If anyone can handle that it is probably Mike, but most of us would not be happy campers in that situation!

Thanks to the PCU5000 and an engine with a nice tight vascular system, mine can maintain coarse pitch when windmilling at approach speed just fine. I’m a glider pilot so I’ve come to enjoy controlling my approach angle by simply leaving power at a very low setting and trimming airspeed constant while using the blue knob like the spoiler control on a sailplane to dial in the glide-path. One plus of all the available drag is that you can easily put an approach entered at very high speed and altitude on the numbers at full stall with impunity. I’m not talking about a minor difference from other constant speed props here, this is profound.

To put it in a nutshell, if I opened my hangar one day to find that someone had put the FP Sensenich back on my airplane(and of course deposited about $15K back into my bank account!), I’d be ordering another Hartzell Composite without the slightest hesitation, but I appreciate that it is not the prop for everyone. I’d be happy to respond to any questions or comments.- Otis
 
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My RV-9A really wants a constant speed, but I've only got an O-320... And the price of the composite prop is spectacular!

Ed
 
My RV-9A really wants a constant speed, but I've only got an O-320... And the price of the composite prop is spectacular!

Ed

I?d be tempted by the whirlwind for that combo. 180HP works well with the Hartzell Composite, but I actually think the optimal match would be 200HP. The Hartzell is a work of art, but you are correct- they do not give it away. I was told but have not confirmed that the option of upgrading a 3-blade Cirrus from aluminum runs about $25K. If true, it does make the deal with Van?s look relatively pretty good!
 
I have had my whirlwind 200 rv prop on order since late july and still waiting on delivery. I like the whirlwind props, but their lead times are horrendous.
 
Hartzell Composite Prop

I have the 8301 Blades with the "B" hub on my RV-10 and love it !!!! By doing this I saved 16 ish POUNDS as compared to the BA aluminum blades, which allowed me to move the battery to the firewall. This eliminated the 2O cable run from the back and simplified the electrical set up (my opinion). No regrets at all.


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Agreed

Although I can't do back to back comparisons with a different prop, the Hartzell composite on our RV-7A is a great performer. We had a similar one on our DA40, which is why I was not hesitant (other than the cost) to order one for the RV.

Your information is appreciated as it helps affirm the decision.

Hartzell will get another large check from me for the three bladed version for our 10 under construction.

We operate off a fairly rough grass strip, so the additional static thrust really helps get us off the ground quickly.
 
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Good to hear your comparative report over broad range of performance conditions. I have 55 hrs now and nothing to compare it with. The thin-wide blade does seem to have quite good efficiency at higher power settings and lower RPM.

One thing - I encountered the full pitch stop for this prop limiting how low the RPM could be dialed @ 8000'DA, WOT and max power. I could not get below 2300 RPM, as it hits the pitch stop. If leaned it goes down further, but not below 2100. One flight was able to get down to 5.5GPH. It ran smooth at all RPM.

Engine off (ICO), full prop pitch, yielded about 1290 RPM and around 10.7:1 glide ratio @ 105 KTAS.

It seems to have the same speed at 2650 and 2700, maybe that tip effect is at play. Beats Vans book though, so I am pretty happy with it all around. One day I'll find smooth air with sea level density altitude and do a top speed run.

I will reserve final comment on the pitch limitation until after some cross country experience.

Nice that they now come from the factory with the leading edge polished. It really looks good.
 
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I have the 8301 Blades with the "B" hub on my RV-10 and love it !!!! By doing this I saved 16 ish POUNDS as compared to the BA aluminum blades, which allowed me to move the battery to the firewall. This eliminated the 2O cable run from the back and simplified the electrical set up (my opinion). No regrets at all.


23uzyq0.jpg

THAT prop is beautiful! My guess is that it would be too long for trigear, two place RV?s, right?- Otis
 
I think composite is the way to go. Lighter, stronger, and thinner. The new whirlwind 190 series is thinner like the HRT but made for smaller hp. 150 to 200. I have mine on order and am hoping for April 2019. Delivery. First flight sometime after that.
Jackz
 
I agree with Mr Horton...excellent write up! I have been sitting on the fence trying to decide on which direction to go with the prop...but I think that I have just been pushed off the fence!
 
I agree with your report Otis.
My prop is the same, on a YIO-390 (RV14A) : the result is monstrous !:D The plane reacts instantly to power changes. Take off are impressive.
Only issue, partially fixed with 3 turns of Low pitch stop: during acceleration the engine easily crosses 2850 RPM (Now "only" 2780). I have to manage blue knob before rotation.
The cruise is smooth and I like the aircraft maneuverability.
this propeller is great.
Only 12 hours with it.
 
That's a excellent report Otis.

I admit to a bit of propeller envy ;)

That makes two of us.

My hangar neighbor has one bolted to the IO-390 on the front of his RV-14A project. I asked if he?d be willing to swap with my Hartzell B/A for awhile since he won?t be flying for several months. I generously offered to provide real-world back to back comparison numbers to help him rationalize the extra expense of his prop. He wasn?t having it. Oh well...
 
I have the 8301 Blades with the "B" hub on my RV-10 and love it !!!! By doing this I saved 16 ish POUNDS as compared to the BA aluminum blades, which allowed me to move the battery to the firewall. This eliminated the 2O cable run from the back and simplified the electrical set up (my opinion). No regrets at all.


23uzyq0.jpg

Did you deal with Hartzell directly for this prop setup? I cannot find anyone else that has on like it and Vans only offers a 2 blade aluminum or 3 blade composite from Hartzell. I really like the idea of it. I want the lightest, smoothest prop I can get and I'm wondering if this fits the bill!
 
Photo added

I just went back and added a direct link to the photo below of my installation in the initial post of this thread. Trying to do that more now, as I’ve come to realize that many people can’t or don’t access the links to photo albumns. In this thread, nearly 3K views resulted in only about 300 visits to the full albumn!- Otis
2v2Ev48o4xBELK5.jpg
 
I only see that prop for the IO-360 not the IO-540 in an RV-10. Van?s only shows a 3 blade composite for the -10.
 
I am curious about the part # and the cost for the Hartzell 2 bladed composite prop that would work on a RV-10. Would love to know the details.
 
Did you deal with Hartzell directly for this prop setup? I cannot find anyone else that has on like it and Vans only offers a 2 blade aluminum or 3 blade composite from Hartzell. I really like the idea of it. I want the lightest, smoothest prop I can get and I'm wondering if this fits the bill!

Even though they didn't list it, I called Van's and was told I could order through them what I wanted from Hartzell. I had consulted with the engineers at Hartzell and was told that this prop could handle high compression pistons and E.I. (LSE) with no problems. There would also be no worries about RPM avoid ranges:). Make sure that you check the clearances from the trailing edges of the blades and the inlet of the lower cowl. I got the numbers from Hartzell and made sure that I put the Rod Bower inlet on accordingly. Things worked out great. I love this setup still on the RV-10.
 
Awesome Prop

I swapped my Catto 3 blade for the Hartzell composite and also swapped my 0-360 180hp for a BPE XIO-360 200hp angle valve engine in my RV8.
I must say I?m thrilled with the results. For me this is a perfect engine/prop combo! Before the change I cruised 170knts at 6-8000 feet at 2500 rpm and now at 2400rpm at 190knts rich of peak till I?m sure it?s broken in. Take off roll is stunning in my opinion.
I know this is not a very scientific report of my results but this combo works great for me!

Kevin
 
I swapped my Catto 3 blade for the Hartzell composite and also swapped my 0-360 180hp for a BPE XIO-360 200hp angle valve engine in my RV8.
I must say I’m thrilled with the results. For me this is a perfect engine/prop combo! Before the change I cruised 170knts at 6-8000 feet at 2500 rpm and now at 2400rpm at 190knts rich of peak till I’m sure it’s broken in. Take off roll is stunning in my opinion.
I know this is not a very scientific report of my results but this combo works great for me!

Kevin

I would agree that you have hit on an ideal powerplant for this propellor, it will soak up everything your engine can throw at it! If I ever need a major on my 180HP Lyclone, I’ll be very tempted. It would be a tough decision on my 7A, though, as the lightweight prop and lighter weight engine results in spectacular handling, and adding that much polar mass would significantly diminish the nimbleness factor, but what a climber it would become!- Otis
 
To put it in a nutshell, if I opened my hangar one day to find that someone had put the FP Sensenich back on my airplane(and of course deposited about $15K back into my bank account!), I?d be ordering another Hartzell Composite without the slightest hesitation, but I appreciate that it is not the prop for everyone. I?d be happy to respond to any questions or comments.- Otis

Hi Otis, what a great post! This is my first post on VAF, and even though I have been around RVs since the beginning (used to work with Dick at Hyster Co.), I have not and am not building an RV, but a Rans S-21. It will have an IOX-340, 180 hp Titan engine with 9.0:1 CR. Props up to 80" diameter will work on the taildragger I'm building. I've been looking at this prop as a possibility and wondering what your thoughts are about it's suitability for the S-21. Excellent T/O and climb ability are important but so is cruise speed for this quasi-STOL aircraft. There doesn't seem to be many options for this niche market. I guess I need to talk to some engineering/tech people at Hartzell and wondering if you can suggest anyone in particular?
 
classical prop design vs modern prop design

The OP mentioned that Jack Norris had commented about the Hartzell prop not being optimum based on classical propeller theory. In case anyone is interested, I can expand on that a little bit.

Classical theory with some nice refinements leads to propeller blades that are shaped more like the Whirl Wind 200RV prop. However, there is a noteable shortcoming to that classical theory as generally applied, in that it does not include transonic effects.

Including transonic effects in the propeller blade design tends to shift the blade shape toward wider chords that operate at lower lift coefficients to produce the same ideal circulation and lift distribution, and also allows thinner blade sections (at least as a percentage of blade chord if not outright thickness). Thinner thickness to chord ratio and lower lift coefficient both tend to delay transonic drag rise.

So the interesting design challenge here is to optimize the blades for the trade-off of adding more wetted area which is skin friction drag but reduces transonic drag effects.

The fact that the 2-blade Hartzell "Blended Airfoil" prop and the Whirl Wind 200RV prop both provide almost identical cruise speed suggests that, at least at 2400 rpm on a 72" prop (A helical tip Mach number of about 0.7), the design space is rather flat - that is, multiple design points can have very similar performance.
If you are going to race fast, you might find that the Hartzell starts to have an edge.

I might point out that the guys at Hartzell have been designing propellers for a long time, and they know their stuff. You can bet they have modern computational design methods that do a good job of accounting for both transonic and viscous effects.
 
Hi Otis, what a great post! This is my first post on VAF, and even though I have been around RVs since the beginning (used to work with Dick at Hyster Co.), I have not and am not building an RV, but a Rans S-21. It will have an IOX-340, 180 hp Titan engine with 9.0:1 CR. Props up to 80" diameter will work on the taildragger I'm building. I've been looking at this prop as a possibility and wondering what your thoughts are about it's suitability for the S-21. Excellent T/O and climb ability are important but so is cruise speed for this quasi-STOL aircraft. There doesn't seem to be many options for this niche market. I guess I need to talk to some engineering/tech people at Hartzell and wondering if you can suggest anyone in particular?

Hello Kip, thanks for the kind words and welcome to posting on VAF- I get the impression that you have a lot of company in the ?non-RV but paying attention to VAF? crowd. I cannot help but imagine that this prop would be an excellent candidate for your bird. You might pick up some valuable insight reading the post following yours, as you would be taking advantage of the low lift coefficient/high RPM condition during high performance climbouts. The relevance of my RV-only experience with it is purely anecdotal, but I certainly get the impression that the slower I go the harder it pulls during climbouts. In cruise, you will have a ton of margin for extracting everything your engine can produce at lower RPM?s. Sorry I cannot recommend anyonein particular at Hartzell, but the support staff there is quite knowledgable. Good luck- Otis
 
The OP mentioned that Jack Norris had commented about the Hartzell prop not being optimum based on classical propeller theory. In case anyone is interested, I can expand on that a little bit.

Classical theory with some nice refinements leads to propeller blades that are shaped more like the Whirl Wind 200RV prop. However, there is a noteable shortcoming to that classical theory as generally applied, in that it does not include transonic effects.

Including transonic effects in the propeller blade design tends to shift the blade shape toward wider chords that operate at lower lift coefficients to produce the same ideal circulation and lift distribution, and also allows thinner blade sections (at least as a percentage of blade chord if not outright thickness). Thinner thickness to chord ratio and lower lift coefficient both tend to delay transonic drag rise.

So the interesting design challenge here is to optimize the blades for the trade-off of adding more wetted area which is skin friction drag but reduces transonic drag effects.

The fact that the 2-blade Hartzell "Blended Airfoil" prop and the Whirl Wind 200RV prop both provide almost identical cruise speed suggests that, at least at 2400 rpm on a 72" prop (A helical tip Mach number of about 0.7), the design space is rather flat - that is, multiple design points can have very similar performance.
If you are going to race fast, you might find that the Hartzell starts to have an edge.

I might point out that the guys at Hartzell have been designing propellers for a long time, and they know their stuff. You can bet they have modern computational design methods that do a good job of accounting for both transonic and viscous effects.

Steve- Thank you for this valuable post. Anything that sheds light on the “black magic” of propellor design for we neophytes is much appreciated! I’ve intuitively felt that the high “thinness ratio” of this prop was key to its incredible performance. Given that the “twist” of a blade on a CS installation can only be optimized for a particular RPM/speed ratio, it stands to reason that low thinness ratio blades operating at higher lift coefficients might have some very draggy sections with possible flow separation in many scenarios near the limits of pitch travel. I also wonder about the effect, if any, of the oddly slippery surface finish of the carbon fibre blades. It feels “lubricated” when you run your hand over it, not “grabby” like a glossy painted blade. I’m not even trying to disguise my general ignorance here, so no laughing please! -Otis
 
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snip>>
Including transonic effects in the propeller blade design tends to shift the blade shape toward wider chords that operate at lower lift coefficients to produce the same ideal circulation and lift distribution, and also allows thinner blade sections (at least as a percentage of blade chord if not outright thickness). Thinner thickness to chord ratio and lower lift coefficient both tend to delay transonic drag rise.
and my understanding is that the advent of carbon fiber materials allowed the prop designers to finally get to that thin ratio in our size props.
 
and my understanding is that the advent of carbon fiber materials allowed the prop designers to finally get to that thin ratio in our size props.

Yes, that is likely true. Although, even the aluminum BA blades are fairly thin.
 
Otis,

Great review and pictures!

I have an RV-4 with older non-BA Hartzell CS prop that I want to swap for something composite.

Anyone out there with the composite Hartzell on an RV-4?

My plane has a Sam James cowling which makes things a bit more difficult due to the flat front which brings the cooling inlets parallel with the cowling behind the spinner. After many emails and phone calls to WW and engineers at Hartzell I ordered the Hartzell N7605W-2X blades with extended hub today. The WW would have required a large spacer which I would rather avoid.

Now I have to sit and wait 10 weeks but look forward to formation flying and aerobatics with the new Hartzell.
 
Rob Hickman, CEO of Advanced Flight Systems has an RV-4 with a Hartzell Composite prop and is very impressed with it.
 
Otis,

Great review and pictures!

I have an RV-4 with older non-BA Hartzell CS prop that I want to swap for something composite.

Anyone out there with the composite Hartzell on an RV-4?

My plane has a Sam James cowling which makes things a bit more difficult due to the flat front which brings the cooling inlets parallel with the cowling behind the spinner. After many emails and phone calls to WW and engineers at Hartzell I ordered the Hartzell N7605W-2X blades with extended hub today. The WW would have required a large spacer which I would rather avoid.

Now I have to sit and wait 10 weeks but look forward to formation flying and aerobatics with the new Hartzell.

The cowl compatibility issue is partly the inlet/spinner face, but really it is the relationship of blade sweep back relative to the mounting face. This requires a different spinner than Vans. The spinner needs to have it's rear edge about 5/8" (or more) farther aft than the Vans. If not, the spinner face on the cowl must be moved forward. That is quite a bit of work. :eek:

It is my understanding the Hartzell spinner aft edge is farther back relative to the blade pivot center. If someone had kindly provided the dimensions to clearly understand this fact, I would have purchased the Hartzell spinner. The trust-me basis for the recommendation was not accepted as there was no way to verify.

Users with the SJ cowl should get the dimensions from Hartzell to be sure. (verify)
 
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The cowl compatibility issue is partly the inlet/spinner face, but really it is the relationship of blade sweep back relative to the mounting face. This requires a different spinner than Vans. The spinner needs to have it's rear edge about 5/8" (or more) farther aft than the Vans. If not, the spinner face on the cowl must be moved forward. That is quite a bit of work. :eek:

It is my understanding the Hartzell spinner aft edge is farther back relative to the blade pivot center. If someone had kindly provided the dimensions to clearly understand this fact, I would have purchased the Hartzell spinner. The trust-me basis for the recommendation was not accepted as there was no way to verify.

Users with the SJ cowl should get the dimensions from Hartzell to be sure. (verify)

Good points and good advice! The Hartzell spinner is a work of art, and is stabilized by a precision bulkhead that slides snugly over the cylindrical prop-actuating hub, allowing for fore and aft adjustment by altering the number and position of washers at the base plate. Pricey but worth it- I would not attempt installation of this propeller without it. I only wish Hartzell would leave the final blade cutouts to the builder/installer instead of making giant cutouts with enough clearance to slide a finger through all around the blade root, which is almost perfectly cylindrical where it passes through the spinner. This huge gap is indefensible. -Otis
 
I'm currently building an RV 7A that will have the angle valve IO-360-A1B6. I am still looking into what propeller would work best for acro.

I'm leaning towards the MT propeller however I don't want to have too install an extended hub due to the G limitation imposed by that configuration. Does the Hartzell Composite propeller require an extended hub? I would also like to install a shorty Sam James cowl which is the other reason I would like to avoid an extended hub if possible. Lastly how has your prop held up overtime and as the original post was in 2017?

Thanks in advance for your time.
 
I installed the Hartzell composite on my Sam James equipped RV-4 and can say it is an amazing propeller as was the Hartzell customer support. The blades (N7605W-2X) can be ordered with several different length hubs so NO extensions or spacers. The ?standard? hub which works for a Vans cowling RV with metal Hartzell blades is the ?C? hub (HC-C2YR). As noted in other posts, the composite N7605W blades are wide, over 8? wide. On most RV?s the pitch range is around 12 to 34 degrees and with the Sam James cowling that just wont work with a ?C? hub (the blades will hit the cowling when at high pitch). The composite blades with the ?G? hub (on the Vans website) is 1? longer than the ?C? and is used on most RV?s that have the standard Vans cowling. For a Sam James cowling most (like mine) end up with either an ?I? hub (HC-I2YR-1NX) which is 2? longer than the ?C? hub or the ?M? which is 2.5? longer (I recall that is what an RV-7 with long Sam James used).

I highly recommend reviewing the Hartzell application guide searching for ?RV-7? to see others that have installed these propellers:
http://hartzellprop.com/services/product-support-library/manuals/application-guide/

And the owner?s manual which explains the hub numbering:
http://hartzellprop.com/wp-content/uploads/115N-0000-R19-AW.pdf

Then send a note to their customer service. I found them to be VERY helpful:
[email protected]


Mike
 
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