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Prop Swap!

Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
On with the the New:
E49D0BD4-F57D-4E9B-9A7C-A4BE0C32CD3F.jpg

Off with the Old:
87A769FE-90A8-442D-A783-C9CA89DDF34D.jpg

So our RV-3 (“Tsamsiyu”) has been flying since day one with a Whirlwind 151 three-blade prop (the one with the yellow tips). Fabulous propeller - light weight, constant speed, great aerodynamics - that gave us tremendous performance, both in cruise and climb. The airplane will climb 3,000 fpm at sea level, or run down the ocean beach flat out faster than the airframe was designed to go (if you let it). But….nothing lasts forever.

The 151 was one of Jim Rust’s early designs, and he has learned a lot in more than a decade, refining both aerodynamics and mechanics to the point where the 151 has been discontinued in favor of the newer 300 Series (the one with the white tips). And since the 151 was discontinued, he doesn’t have any parts for routine servicing or overhaul. So…..it was only matter of time before it became an expensive paperweight, and since I’ve been very happy with the 300 on our RV-8 for a year, Jim made us a good deal on a new prop for the RV-3.

I flew the airplane down to El Cajon (just east of San Diego) yesterday in cold temperatures (and great tailwinds), arriving about 10:30. By 12:30, the airplane was ready to fly with the new nose! Kudos to Jim and his team, as well as to painter/artist extraordinaire John Stahr who pre-painted the spinner to match the rest of the airplane before the prop was ready. I flew the airplane back to Big Bear for the night, and headed home this morning. Got lucky with tailwinds both ways…..

I didn’t take any solid flight test data, but based on knowing the airplane, I think it is a couple, maybe three knots faster at normal cruise settings in the low teens. We balanced it before leaving El Cajon, and the installation is wonderfully smooth. Climb with this airplane is always outstanding, so I’ll have to do some careful measurements on a calm day to se what kind of improvement we got, but based on previous testing with the -300, I expect to see an extra 10% or so.

The prop certainly looks bigger (it is 70” while the old one was 68”), with a bit broader chord, and Jim said that watching it as I taxied away, it looks powerfully big. And the carbon fiber look is stunning up close.

We’ll see how the 6 lbs extra on the nose feels for aerobatics once it warms up around here!

Paul
 
agent4573 said:
Did your op limits not require a return to phase 1?
Click to expand...

Short answer - no. One constant speed for another that was very similar. Weight and balance change, careful ground testing, and now we’ll go do some delta flight tests. If we’d made a change from fixed pitch to C/S, or some other significant change, then yes - Phase 1 would have been appropriate.

Paul
 
Last edited:
Anything you can share?

6 lbs? Jim usually has the best aerodynamics, so +3 kts is excellent. Has the application envelope expanded for the 6 lb or something else?

Beautiful prop, as per usual.
 
Ironflight said:
On with the the New:
View attachment 38428

Off with the Old:
View attachment 38429

So our RV-3 (“Tsamsiyu”) has been flying since day one with a Whirlwind 151 three-blade prop (the one with the yellow tips). Fabulous propeller - light weight, constant speed, great aerodynamics - that gave us tremendous performance, both in cruise and climb. The airplane will climb 3,000 fpm at sea level, or run down the ocean beach flat out faster than the airframe was designed to go (if you let it). But….nothing lasts forever.

The 151 was one of Jim Rust’s early designs, and he has learned a lot in more than a decade, refining both aerodynamics and mechanics to the point where the 151 has been discontinued in favor of the newer 300 Series (the one with the white tips). And since the 151 was discontinued, he doesn’t have any parts for routine servicing or overhaul. So…..it was only matter of time before it became an expensive paperweight, and since I’ve been very happy with the 300 on our RV-8 for a year, Jim made us a good deal on a new prop for the RV-3.

I flew the airplane down to El Cajon (just east of San Diego) yesterday in cold temperatures (and great tailwinds), arriving about 10:30. By 12:30, the airplane was ready to fly with the new nose! Kudos to Jim and his team, as well as to painter/artist extraordinaire John Stahr who pre-painted the spinner to match the rest of the airplane before the prop was ready. I flew the airplane back to Big Bear for the night, and headed home this morning. Got lucky with tailwinds both ways…..

I didn’t take any solid flight test data, but based on knowing the airplane, I think it is a couple, maybe three knots faster at normal cruise settings in the low teens. We balanced it before leaving El Cajon, and the installation is wonderfully smooth. Climb with this airplane is always outstanding, so I’ll have to do some careful measurements on a calm day to se what kind of improvement we got, but based on previous testing with the -300, I expect to see an extra 10% or so.

The prop certainly looks bigger (it is 70” while the old one was 68”), with a bit broader chord, and Jim said that watching it as I taxied away, it looks powerfully big. And the carbon fiber look is stunning up close.

We’ll see how the 6 lbs extra on the nose feels for aerobatics once it warms up around here!

Paul
Click to expand...

Looks spectacular. Something about 3-blade props - they are just beautiful.
 
BillL said:
6 lbs? Jim usually has the best aerodynamics, so +3 kts is excellent. Has the application envelope expanded for the 6 lb or something else?
Click to expand...

Hi Bill,

Not quite sure I understand the question, but if its “why did he accept a 6 lb weight hit when designing the prop?” It’s a newer hub design that incorporates lessons from his earlier designs. We did an article in Kitplanes last year where we showed the internals of the new hub if you want to see how it looks inside. The older (lighter) hub design on the 151 had a tendency to spit grease, and required occasionally re-shimming to stop that. The new hub design is larger, which probably accounts for most of the weight increase, although the larger blade chord certainly means the blades add a little weight.

I’ll report more on the performance when I have a chance to do some testing, as well as if the extra nose weight is noticeable. On the RV-8, when I went from a 58 lb Hartzell to the 36 lb WW-300, there was a real difference in handling. I suspect I’ll notice a difference on the much smaller RV-3, but I also am older and do less aggressive Acro than I used to, so it probably won’t impact me….

Paul
 
The 151 was one of Jim Rust’s early designs, and he has learned a lot in more than a decade, refining both aerodynamics and mechanics to the point where the 151 has been discontinued in favor of the newer 300 Series (the one with the white tips). And since the 151 was discontinued, he doesn’t have any parts for routine servicing or overhaul. So…..it was only matter of time before it became an expensive paperweight,

Hmmm.
I wonder how I'd feel if an airframe part, or an engine part became unavailable after one decade simply because a 'better' complete airframe or engine was available.
 
rv7charlie said:

Hmmm.
I wonder how I'd feel if an airframe part, or an engine part became unavailable after one decade simply because a 'better' complete airframe or engine was available.
Click to expand...


Probably the same as I feel about my Garmin 430 not being upgradable or repaired at a reasonable price and older GRT, Dynon equipment becoming paper weights forcing equipment upgrades. Everything today is throw away after a few years with tech support becoming harder. Even my 65” TV became an antique after five years.
 
With electronics I can understand not being able to repair due to non-existence of obsolete chips, but propellers are a mechanical device and should be able to be serviced easily into the future.

I have a 20-year-old Hartzell with 7666 blades which is technically obsolete, but I can still get a factory-sanctioned overhaul for around $3000. Having to spring for a new $15,000 propeller every 10 years makes me think twice about buying a Whirlwind.
 
rv7charlie said:
The 151 was one of Jim Rust’s early designs, and he has learned a lot in more than a decade, refining both aerodynamics and mechanics to the point where the 151 has been discontinued in favor of the newer 300 Series (the one with the white tips). And since the 151 was discontinued, he doesn’t have any parts for routine servicing or overhaul. So…..it was only matter of time before it became an expensive paperweight,

Hmmm.
I wonder how I'd feel if an airframe part, or an engine part became unavailable after one decade simply because a 'better' complete airframe or engine was available.
Click to expand...

I wondered the same thing. Maybe if anyone with an obsolete series 151 prop will get a “good deal” on the latest and greatest - it wouldn’t bother them as much.

Has Hartzell made certain props or hubs obsolete?
 
KatanaPilot said:
Has Hartzell made certain props or hubs obsolete?
Click to expand...

Uhh…you mean the old “A” hubs that require magnetic inspection every 100 hours? Yeah….you don’t want one of those if you can help it!

Seriously folks, you don’t seem to understand that some of the greatest invocations in experimental aviation have come from small companies that keep improving their products, sometimes to the point of making new ones that render support for their original ones untenable. If you’d like to advise Whirlwind in their business practices, you can write to them directly. Not the purpose of this thread.

Whirlwind makes outstanding props, and the most recent news is that you can get them directly from the source in El Cajon - the Ohio facility (that many folks have have trouble with) is no longer selling/servicing Whirlwind.

But you have a distinct choice, which is great - if you don’t like Whirlwind, don’t buy from them. When I tested the Hartzell composite three-blade that compares directly in performance with the WW-300, it was priced at something north of $23K, while the WW-300 (at that time) was about $13K…..

Paul
 
Ironflight said:
Uhh…you mean the old “A” hubs that require magnetic inspection every 100 hours? Yeah….you don’t want one of those if you can help it!

Seriously folks, you don’t seem to understand that some of the greatest invocations in experimental aviation have come from small companies that keep improving their products, sometimes to the point of making new ones that render support for their original ones untenable. If you’d like to advise Whirlwind in their business practices, you can write to them directly. Not the purpose of this thread.

Whirlwind makes outstanding props, and the most recent news is that you can get them directly from the source in El Cajon - the Ohio facility (that many folks have have trouble with) is no longer selling/servicing Whirlwind.

But you have a distinct choice, which is great - if you don’t like Whirlwind, don’t buy from them. When I tested the Hartzell composite three-blade that compares directly in performance with the WW-300, it was priced at something north of $23K, while the WW-300 (at that time) was about $13K…..

Paul
Click to expand...

+1 Paul:

But, I still call Ohio (as recently as this past week) with tech support matters.
[And I have reached out to Jim in CA on a VERY technical matter.]

Have they now shifted EVERYTHING to California???

Just checking.
 
Ironflight said:
Uhh…you mean the old “A” hubs that require magnetic inspection every 100 hours? Yeah….you don’t want one of those if you can help it!

Seriously folks, you don’t seem to understand that some of the greatest invocations in experimental aviation have come from small companies that keep improving their products, sometimes to the point of making new ones that render support for their original ones untenable. If you’d like to advise Whirlwind in their business practices, you can write to them directly. Not the purpose of this thread.

Whirlwind makes outstanding props, and the most recent news is that you can get them directly from the source in El Cajon - the Ohio facility (that many folks have have trouble with) is no longer selling/servicing Whirlwind.

But you have a distinct choice, which is great - if you don’t like Whirlwind, don’t buy from them. When I tested the Hartzell composite three-blade that compares directly in performance with the WW-300, it was priced at something north of $23K, while the WW-300 (at that time) was about $13K…..

Paul
Click to expand...

Paul,

I think most of us understand the innovations provided by the smaller companies. I have SDS on my RV-10 and pMags on my former RV-7. They are innovative products, but there is certainly a risk of installing components on your airplane that come from companies with one or two key personnel.

As to the cost differential between a WW and Hartzell prop - I suspect that a large portion of that is due to the engineering, manufacturing and testing criteria required for certification that Hartzell follows but WW does not.
 
jclark said:
+1 Paul:

But, I still call Ohio (as recently as this past week) with tech support matters.
[And I have reached out to Jim in CA on a VERY technical matter.]

Have they now shifted EVERYTHING to California???

Just checking.
Click to expand...

Hey James,

According to Jim, Whirlwind Ohio is no longer a distributor or service center as of last Monday. The opening splash on the Ohio web site says that (in butchered cut-and-paste text….) as well.
 
Ironflight said:
Hey James,

According to Jim, Whirlwind Ohio is no longer a distributor or service center as of last Monday. The opening splash on the Ohio web site says that (in butchered cut-and-paste text….) as well.
Click to expand...

THANKS!!

I was probably one of the LAST callers then. :)
 
Ironflight said:
Short answer - no. One constant speed for another that was very similar. Weight and balance change, careful ground testing, and now we’ll go do some delta flight tests. If we’d made a change from fixed pitch to C/S, or some other significant change, then yes - Phase 1 would have been appropriate.

Paul
Click to expand...

Thanks for the info. I thought changing the diameter would be considered a major change. It makes sense that going from one CS to another CS can be done easily.
 
So a little data….

Took the airplane over to Carson City today to fuel it up after the trip, but fist did a level flight sped run at 8500’ MSL. Prop and throttle full forward, leaned to peak power (50 ROP), and the TAS was….. 181 knots! That’s in an airplane with a redline of 183.

I’d have to dig through a ton of data to find what it did at 8K during Phase 1, but vague memory tells me we’ve gained about 3 knots with the new prop. And climb off our 4400’ altitude runway was about 2200 fpm today….
 
Comparing your two photos shows that the new blades transition to the blade airfoil from the hub a little closer to the hub, and it looks like there's a bit of sweep in the outer portion compared to the older prop.

Dave
 
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