Flying Behind the Hartzell 2C1-R419A1X/75CS08-2X Composite for a Bit

[DeltaRomeo]

Hartzell reached out a few months back and asked if I would like to try their composite prop for a few weeks. Carbon Blended Airfoil / Engineering model designation: 2C1-R419A1X/75CS08-2X. Shortened a few places to '75CS08'. FMI pages 1-18 at: https://hartzellprop.com/EXP-AIRCRAFT/Man-193-Vol-03.pdf

It’s the same prop DanH flew awhile back - I got it after Dan. His writeup HERE.

Our family’s RV-6 ‘Flash’ was in a perfect storm of condition inspection (its 22nd), me doing more part time sims than usual, hot weather, OSH coverage and P-mags needing a scheduled love up during their purchase/transition/OSH. Long story short my last RV flight was May 31. Two and a half months. Disgraceful.


Condition inspection completed Aug 11 by the amazing Randy ‘Monkey’ Richmond. He worked some Monk Magic, and we’re going to do a little baffle work here in a few weeks when I get some supplies. I flew it for a bit on the 12th while rain hovered west of the field, bringing the temps down to a very welcome 80F. Even better aloft. Not a lot of gas onboard, so stayed close to the field. The next flight will be a gas run, and I can get some cruise numbers.




Like Dan wrote, ~20 lbs lighter than my existing alum blended Hartzell. That weight reduction so far forward of the datum….Dan did the math in his writeup. It’s very, very noticeable.

Startup mass:
When the EarthX put the spurs to it I was a little jolted at how instantly fast things were spinning. That’s new for me. More sensitive to the throttle control inputs, too. Seemed to have POWER more instantaneously. If you don’t know, my engine is an ECi kit build 180 hp clone that Danny King helped me build up about two decades ago. Regular ‘ol carb.

Takeoff:
Seemed to get up on the rolling step faster than I remember, and things seemed to be at the thrust set line item quicker. Normal pull and climb. Quieter. Smoother.

Turns:
Noticeable change. With the weight savings, more balanced in pitch - like I had back with Flash’s original 150hp/fixed pitch setup. Stick forces are roughly back to the same whether fore/aft or left/right. The dialed in ‘RV feel’ if you will. The downside with upgrading to 180/CS 20 yrs back was that things ‘got thick’ in pitch. My reference line for ‘feel’ is an RV-4 Jay Pratt owned for a few months many years ago. That was the most perfectly balanced RV I’ve ever flown. I wish he still had it ;^). I wish *I* had it.

Pics I took in flight to look at later for numbers, so I could concentrate on flying...




Shutdown:
Things just stop. Fast. New to me.

Looking forward to a few more hours, and getting some numbers before sending it back to Hartzell. I need to run down to San Antonio sometime in the future, so that will be a good 3 hours round trip of data round trip. Some baffling work is on the list for the near future as well, as #1 and #2 are a little apart.

Fun to play with new tech every now and then.




Quite an amazing propellor. Appreciate Hartzell letting me play with it.

I’ll leave this as a sticky here at the top of the Propellors sub-forum and as I get more info I’ll post it.

v/r,dr

PS: Pic of ‘just out of fresh annual’ new grease slung out of the TW. The hobby makes a mess. We smile.

 

[smokyray]

View attachment 94800

Hartzell reached out a few months back and asked if I would like to try their composite prop for a few weeks. Carbon Blended Airfoil / Engineering model designation: 2C1-R419A1X/75CS08-2X. Shortened a few places to '75CS08'. FMI pages 1-18 at: https://hartzellprop.com/EXP-AIRCRAFT/Man-193-Vol-03.pdf

It’s the same prop DanH flew awhile back - I got it after Dan. His writeup HERE.

Our family’s RV-6 ‘Flash’ was in a perfect storm of condition inspection (its 22nd), me doing more part time sims than usual, hot weather, OSH coverage and P-mags needing a scheduled love up during their purchase/transition/OSH. Long story short my last RV flight was May 31. Two and a half months. Disgraceful.
View attachment 94802

Condition inspection completed Aug 11 by the amazing Randy ‘Monkey’ Richmond. He worked some Monk Magic, and we’re going to do a little baffle work here in few weeks when I get some supplies. I flew it for a bit on the 12th while rain hovered west of the field, bringing the temps down to a very welcome 80F. Even better aloft. Not a lot of gas onboard, so stayed close to the field. The next flight will be a gas run, and I can get some cruise numbers.
View attachment 94801
View attachment 94803
View attachment 94804

Like Dan wrote, ~20 lbs lighter than my existing alum blended Hartzell. That weight reduction so far forward of the datum….Dan did the math in his writeup. It’s very, very noticeable.

Startup mass:
When the EarthX put the spurs to it I was a little jolted at how instantly fast things were spinning. That’s new for me. More sensitive to the throttle control inputs, too. Seemed to have POWER more instantaneously. If you don’t know, my engine is an ECi kit build 180 hp clone that Danny King helped me build up about two decades ago. Regular ‘ol carb.

Takeoff:
Seemed to get up on the rolling step faster than I remember, and things seemed to be at the thrust set line item quicker. Normal pull and climb. Seemed quieter.

Turns:
Noticeable change. With the weight savings, more balanced in pitch - like I had back with Flash’s original 150hp/fixed pitch setup. Stick forces are roughly back to the same whether fore/aft or left/right. The dialed in ‘RV feel’ if you will. The downside with upgrading to 180/CS 20 yrs back was that things ‘got thick’ in pitch. My reference line for ‘feel’ is an RV-4 Jay Pratt owned for a few months many years ago. That was the most perfectly balanced RV I’ve ever flown. I wish he still had it ;^). I wish *I* had it.

Pics I took in flight to look at later for numbers, so I could concentrate on flying...
View attachment 94806
View attachment 94807
View attachment 94808

Shutdown:
Things just stop. Fast. New to me.

Looking forward to a few more hours, and getting some numbers before sending it back to Hartzell. I need to run down to San Antonio down the road, so that will be a good 4 hours of data. Some baffling work is on the list for the near future as well, as #1 and #2 are a little apart.

Fun to play with new tech every now and then.

View attachment 94809
View attachment 94810

Quite amazing propellor. Appreciate Hartzell letting me play with it.

I’ll leave this as a sticky here at the top of the Propellors sub-forum and as I get more info I’ll post it.

v/r,dr

PS: Pic of ‘just out of annual’ new grease slung out of the TW. The hobby makes a mess. We smile.

View attachment 94811

Nicely done my friend. Your write up is very reminiscent of my own comparison way back in 99’ after removing and selling my (hideous) Sensy 70CM metal FP in lieu of a custom Catto 2 blade, the first ever on an RV4. I had also comparison flown several 180-C/S B hub Hartzell RVs at that that time and found them noseheavy and plenty of flywheel effect, something I greatly dislike. Over the next 26 years I’d have lots of opportunities to compare my own RV4 and 6X with others and enjoy the original prototype RV Catto on my 4 and the Gen 2 2 blade with nickel LEP on my X, both sporting them to this day although the current owner of my 4 has an MT 2 blade FP up front. Nicely done my friend! Always great to hear of your adventures!

Now…will Hartzell letcha keep it???

V/R
Smokey

 

[DeltaRomeo]

Now…will Hartzell letcha keep it???

I am guessing they will not. LOL

Sure is purdy, tho. The tech just gets more and more amazing.

 

[BillL]

I sure wish they would offer me that prop test. I'll have to spend $20k+ to find out how slow my plane is.

Great report Doug, thanks!!

 

[DeltaRomeo]

Another flight with the Hartzell 2C1-R419A1X/75CS08-2X Composite

(bullet points cuz I’m lazy)

• 14 days days since my last flight (the 2nd w/this prop)
• 78°F and a 90* cross wind
• Still stunned at how fast that prop turns when you hit the key
• Randy was over in his golf cart watching and I had about 8 gallons of fuel and no bags, so I put the boresight on 15° and climbed out at about 95 kts to pattern alt
• Still getting used to the different smoothness and slightly less noise
• Definitely less gyroscopic effect. Less mass. Turns seem more balanced.
• Pitch sensitivity has definitely increased due to the lighter weight
• Shut down at Bridgeport for gas. Again stunned at how fast it stops
• Set up for a lazy trip back and I think it’s a higher pitch noise than my previous prop but less loud overall
• You have to move the throttle more carefully due to a smaller gyroscopic effect. It’s a little harder to get the idle where you want it. Getting better
• Of course coming back to our field there was a 90° crosswind from the north east and that always gives turbulent air over the hangers next to the runway, so I looked like a total newbie in the flare. Having so much less weight now on the front, still kind of getting used to that. Overcorrected. I got it down, but I’m glad no one saw me. Edit: Kay saw me. Damn.
• Some baffling work during the annual has the cylinder head temperatures a little lower. And the oil is kind of getting where I want it. Still tweaking.
• I’m kind of hoping Hartzell forgets I’m borrowing this. Maybe I can paint my existing prop black and send that back to them. Do you think they will notice?
• I’m kind of liking this prop. It makes me look cooler than I am.

PS: Unrelated….having traffic in the cockpit is useful. There must’ve been 12 different archers between my home base and Bridgeport out doing training. It was a nice morning for flying.

Assorted pictures from the outing:


.

 

[Daddyman58]

Another flight with the Hartzell 2C1-R419A1X/75CS08-2X Composite

(bullet points cuz I’m lazy)

• 14 days days since my last flight (the 2nd w/this prop)
• 78°F and a 90* cross wind
• Still stunned at how fast that prop turns when you hit the key
• Randy was over in his golf cart watching and I had about 8 gallons of fuel and no bags, so I put the boresight on 15° and climbed out at about 95 kts to pattern alt
• Still getting used to the different smoothness and slightly less noise
• Definitely less gyroscopic effect. Less mass. Turns seem more balanced.
• Pitch sensitivity has definitely increased due to the lighter weight
• Shut down at Bridgeport for gas. Again stunned at how fast it stops
• Set up for a lazy trip back and I think it’s a higher pitch noise than my previous prop but less loud overall
• You have to move the throttle more carefully due to a smaller gyroscopic effect. It’s a little harder to get the idle where you want it. Getting better
• Of course coming back to our field there was a 90° crosswind from the north east and that always gives turbulent air over the hangers next to the runway, so I looked like a total newbie in the flare. Having so much less weight now on the front, still kind of getting used to that. Overcorrected. I got it down, but I’m glad no one saw me. Edit: Kay saw me. Damn.
• Some baffling work during the annual has the cylinder head temperatures a little lower. And the oil is kind of getting where I want it. Still tweaking.
• I’m kind of hoping Hartzell forgets I’m borrowing this. Maybe I can paint my existing prop black and send that back to them. Do you think they will notice?
• I’m kind of liking this prop. It makes me look cooler than I am.

PS: Unrelated….having traffic in the cockpit is useful. There must’ve been 12 different archers between my home base and Bridgeport out doing training. It was a nice morning for flying.

Assorted pictures from the outing:
View attachment 96018

.
View attachment 96028


View attachment 96029

View attachment 96030

DR,
Nice write up.
Daddyman58

 

[Stevea]

• I’m kind of liking this prop. It makes me look cooler than I am.

No way. Flying an RV already makes you look cooler than you are. Me too.

 

[Full Throttle]

Some baffling work is on the list for the near future as well, as #1 and #2 are a little apart.

Just increase the number two nozzle re-strickter by .0005 and you should be where you want it. #2 will come down and #1, 3, and 4 will go up a little.

 

[DeltaRomeo]

Update: Flight #3. Sept 16, 2025.

One more flight on the borrowed Hartzell Composite. First RV flight since Aug 26th (ugh). Amazingly smooth. More quiet than my regular prop. Lighter plane climbs more aggressively. More equally balanced between pitch and roll. Lazy turns right and left are a joy in the morning calm. Look at that after takeoff climbing turn ground track. Happy happy. Morning sunlight sure is a gift.
Counted (15) deer....two bucks....and (2) feral hogs.
I hope Hartzell forgets I’m borrowing this - thinking about painted my old prop black and putting it in the shipping box for the trip back. LOL.
v/r,dr

 

[DeltaRomeo]

Another hop with the Hartzell 2C1-R419A1X/75CS08-2X Composite

It’s been 17 days since my last RV flight, and the scheduling and weather gods created a space in the universe for me to go enjoy flight for a bit. With the part time simulator stomping on my head and the part time occasional contract flight that averages out to about a 14 hour day, I was needing uncluttered, unforced, non-autopilot time off of the surface. My patient, wonderful, 23 year-old RV delivered once again.

No plan. No autopilot. Minimal talk, enjoying gentle turns in the morning red shifted light. Trimmed up and smooth. Fingertip effort. Cows and the occasional feral pig. Fields getting cut.

I really wish I had more technical information to report on this propeller I’ve been borrowing from Hartzell for a little time now, but this was one of those flights where I just dialed everything back to about 8 1/2 gallons an hour and enjoyed the scenery at 1000 feet. Other than the smoothness and the shocking rate of rotation at engine start, I don’t think I thought about the propeller one time. It’s just there doing what it needs to do.

Started to head out toward some unoccupied farmland for acrobatics, but realized I was enjoying just puttering along, in no sweat mode, not having to do math in my head. So I just kept doing that. Setup for the overhead break with a semi respectable tail low left wheel first due to the crosswind landing. No one saw it.

My mental gyros got a much-appreciated reset. My world sort of rotates around technology stuff, and sometimes after a few weeks of bombardment I find I just need to go do something in caveman mode.

Takeoff, look around, smile, land. Eat. Nap. These planes are good for that.

I’m probably gonna need to start thinking about taking this propeller off and sending it back to Hartzell. They were really kind to let me borrow it for awhile. I’m gonna miss this thing, as it’s pretty much the nicest propeller I’ve flown behind.

Some pictures in no particular order below. I do like pictures of grease being slung around. This prop looks and performs really, really well.

It makes me look cooler than I am.

v/r,dr

Morning light and cricket pads...


Grease = fun.


Coolest plane eva


Proof...


PS: When I got home, the simulator called and asked if I could come in both Saturday and Sunday. See how that works, universe?

Hey, I got to fly my RV. I’m all good.

 

[bjdecker]

@DeltaRomeo

That tailwheel is just embarrassing ...

-- or -- the 1920's called and they want their tailwheel back
-- or -- Some poor schmuck on IH-35 is wondering where the grease drips on his windshield came from...

Come on folks, let's hook up Doug with a sample tailwheel from this decade!

 

[Mikeyb]

@DeltaRomeo

That tailwheel is just embarrassing ...

-- or -- the 1920's called and they want their tailwheel back
-- or -- Some poor schmuck on IH-35 is wondering where the grease drips on his windshield came from...

Come on folks, let's hook up Doug with a sample tailwheel from this decade!

Probably more embarrassing, correct me if I’m wrong but it looks like he is putting grease in the fitting on the stock tail wheel with the path to nowhere.

 

[DeltaRomeo]

Fresh condition inspection and I don’t fly enough. It slings a little grease after each inspection. It’ll find equilibrium here in a coupla more flights. I gotta system that leaves the tailwheel luxuriously moisturized.

 

[Jonnyb]

@DeltaRomeo

Has the prop gone back now Doug? Overall thoughts on it?

 

[Jjackh10]

@DeltaRomeo

That tailwheel is just embarrassing ...

-- or -- the 1920's called and they want their tailwheel back
-- or -- Some poor schmuck on IH-35 is wondering where the grease drips on his windshield came from...

Come on folks, let's hook up Doug with a sample tailwheel from this decade!

I was wondering how grease got all the way up my trucks windshield!

I'll chip in some loot. Maybe adding a titanium fork from aerogarage also would motivate him to keep it shiny?

 

[DeltaRomeo]

@DeltaRomeo

Has the prop gone back now Doug? Overall thoughts on it?

Still on the airplane for one or two more flights. I may actually try to get a little time in the air today if the calendar allows - of course it’s 30° outside as I’m dictating this at 6:27 AM local still in bed . There is a non-zero chance the simulator is going to reach out in an hour or two…

You know this would actually be a pretty good opportunity to get a cold air flight in with it. In need of a gas run up to Gainesville anyway.

Where did I put those thicker socks? What does the turbulence layer look like?

v/r,dr

 

[Jonnyb]

You know you want to Doug!

 

[DeltaRomeo]

12/30/2025 flight….

29*F at arrival.

Need gas. GLE has it for $4.30 18 minutes away.

More than a few had the same idea.

00000kts / CAVU


Plane off the ground before the throttle was all the way in.

Still the smoothest prop I’ve flown behind that wasn’t turbine-powered.

Route up. Planned for passage over various runways on the way, steering the A/P in heading mode to follow the line on my iPhone.


On the ramp KGLE. Texas blue sky!



ForeFlight debrief gave me a score of 99 on the way up. Rare for this always-a-student-pilot.


Prop on loan. I sure wish they would forget I have this thing, as it’s probably the nicest propellor I’ll ever fly behind. NOTICEABLY lighter than the metal. More balanced in pitch.


Headed back around the other side of DTO. Traffic opportunities.


Cruise. Dialed back. 8.6 gph flow. 9kt tailwind. 149kt GS. 138 IAS.


Westerly view. CAVU


Hazard Awareness overlay on as I get closer to home.



Hat pic post-putting it away:


I’m going to miss this prop. Thanks again to Hartzell for letting me play with it for a bit. Amazing tech.

Got my nerd on and the mental gyros are centered up again for awhile. Going for one last flight in 2025 was a good idea….one more thing to be thankful for.

v/r,dr

 

[Jonnyb]

Cheers Doug!
Looked like a great flying day!

Did the silver spinner come with the prop?

 

[Jjackh10]

Hat pic post-putting it away:
View attachment 105976

I’m going to miss this prop. Thanks again to Hartzell for letting me play with it for a bit. Amazing tech.

Got my nerd on and the mental gyros are centered up again for awhile. Going for one last flight in 2025 was a good idea….one more thing to be thankful for.

v/r,dr

How does a guy go about acquiring swag like a hat, shirt, coffee mug, etc?

 

[DeltaRomeo]

How does a guy go about acquiring swag like a hat, shirt, coffee mug, etc?

Here’s my charity cap link that I used to promote the website. Other Vans related merchandise available on the mothership.

VAF Charity Cap: Help your charity and promote this site.

Get the cap all the cool kids are wearing! I don’t get a penny. It’s around $15. $5 more if you want your N-number on the back (I put 'STAFF' on the back of mine because it makes me laugh. Put STAFF on yours too if it makes you smile). And down the road $10 to the charity of your choice...

vansairforce.net

 

[DeltaRomeo]

Did the silver spinner come with the prop?

Yes, it did. I just bolted everything on. Sending it back with the prop here in a bit.

 

[MWH265]

I'm sure Hartzell will let you keep it. Just takes a phone call and a check.

 

[Michael White]

I'm sure Hartzell will let you keep it. Just takes a phone call and a check.

The phone call is easy. The check is the hard part...

 

[Hitt7A]

Never seen a Hurst with a luggage rack, spend the money, buy the prop.

 

[Michael White]

Well, maybe not with a luggage rack...

 

[803RV]

View attachment 94800

Hartzell reached out a few months back and asked if I would like to try their composite prop for a few weeks. Carbon Blended Airfoil / Engineering model designation: 2C1-R419A1X/75CS08-2X. Shortened a few places to '75CS08'. FMI pages 1-18 at: https://hartzellprop.com/EXP-AIRCRAFT/Man-193-Vol-03.pdf

It’s the same prop DanH flew awhile back - I got it after Dan. His writeup HERE.

Our family’s RV-6 ‘Flash’ was in a perfect storm of condition inspection (its 22nd), me doing more part time sims than usual, hot weather, OSH coverage and P-mags needing a scheduled love up during their purchase/transition/OSH. Long story short my last RV flight was May 31. Two and a half months. Disgraceful.
View attachment 94802

Condition inspection completed Aug 11 by the amazing Randy ‘Monkey’ Richmond. He worked some Monk Magic, and we’re going to do a little baffle work here in a few weeks when I get some supplies. I flew it for a bit on the 12th while rain hovered west of the field, bringing the temps down to a very welcome 80F. Even better aloft. Not a lot of gas onboard, so stayed close to the field. The next flight will be a gas run, and I can get some cruise numbers.
View attachment 94801
View attachment 94803
View attachment 94804

Like Dan wrote, ~20 lbs lighter than my existing alum blended Hartzell. That weight reduction so far forward of the datum….Dan did the math in his writeup. It’s very, very noticeable.

Startup mass:
When the EarthX put the spurs to it I was a little jolted at how instantly fast things were spinning. That’s new for me. More sensitive to the throttle control inputs, too. Seemed to have POWER more instantaneously. If you don’t know, my engine is an ECi kit build 180 hp clone that Danny King helped me build up about two decades ago. Regular ‘ol carb.

Takeoff:
Seemed to get up on the rolling step faster than I remember, and things seemed to be at the thrust set line item quicker. Normal pull and climb. Quieter. Smoother.

Turns:
Noticeable change. With the weight savings, more balanced in pitch - like I had back with Flash’s original 150hp/fixed pitch setup. Stick forces are roughly back to the same whether fore/aft or left/right. The dialed in ‘RV feel’ if you will. The downside with upgrading to 180/CS 20 yrs back was that things ‘got thick’ in pitch. My reference line for ‘feel’ is an RV-4 Jay Pratt owned for a few months many years ago. That was the most perfectly balanced RV I’ve ever flown. I wish he still had it ;^). I wish *I* had it.

Pics I took in flight to look at later for numbers, so I could concentrate on flying...
View attachment 94806
View attachment 94807
View attachment 94808

Shutdown:
Things just stop. Fast. New to me.

Looking forward to a few more hours, and getting some numbers before sending it back to Hartzell. I need to run down to San Antonio sometime in the future, so that will be a good 3 hours round trip of data round trip. Some baffling work is on the list for the near future as well, as #1 and #2 are a little apart.

Fun to play with new tech every now and then.

View attachment 94809
View attachment 94810

Quite an amazing propellor. Appreciate Hartzell letting me play with it.

I’ll leave this as a sticky here at the top of the Propellors sub-forum and as I get more info I’ll post it.

v/r,dr

PS: Pic of ‘just out of fresh annual’ new grease slung out of the TW. The hobby makes a mess. We smile.

View attachment 94811

Dan, I'm getting ready to purchase engine and prop for 14A. I'll get the IO-390EXP and know I want a 74 inch composite prop. A fellow builder has the HC-G2YR on his 14A and loves it. Your write up and performance specs on the 75CS08 has me interested. The Hartzell prop manual says there are modifications required for the 75CS08 hub/spinner and I know my friend's HC-G2YR just bolted on. Did you have to do any hub/spinner modifications to swap props?

 

[DeltaRomeo]

No sir. They sent me the prop and the spinner and they just bolted right on.

 

[TParker]

The Hartzell prop manual says there are modifications required for the 75CS08 hub/spinner and I know my friend's HC-G2YR just bolted on. Did you have to do any hub/spinner modifications to swap props?

To clarify, the modifications the manual talk about are modifications to the Van's kit supplied spinner; one of the mods is to the mounting locations, which are slightly different spacing, and the other mod is for the spinner forward bulkhead attach holes which only applies to retrofits where a previously used kit spinner is being attached to the new prop.

If you want to use the Van's kit spinner you can, but will need to alter the spinner build slightly to pick up the alternate mounting locations, as detailed in the manual (there's also a template in the back of the manual), and make different blade cutouts/filler plates as the Van's spinner kit instructions are specific to the aluminum bladed prop.

If you use the aluminum spinner we offer for this prop, no adjustments are necessary.

 

[DanH]

This prop and polished spinner are bolt on and done.

I like my screwless Vans spinner, but I would retire it for this one...

 

[bjdecker]

This prop and polished spinner are bolt on and done.

I like my screwless Vans spinner, but I would retire it for this one...

View attachment 106638

Looks like the cowling "reveal" is a bit more with that spinner; or is that an optical illusion?

 

[DanH]

Looks like the cowling "reveal" is a bit more with that spinner; or is that an optical illusion?

I think the engine has moved a bit on the mounts. CI coming up soon!

 

[TParker]

This prop and polished spinner are bolt on and done.

I like my screwless Vans spinner, but I would retire it for this one...

Well, the polished spinner was designed so that it's a bolt in replacement on the aluminum BA prop as well; its mounting holes are slotted so it works with either prop. So you could do just that

 

[Mikeyb]

I love this thing