While some would like to believe that the Hartzell is the fastest prop, there is mounting evidence from new flight test data that this may not be true. I'll take the flight test data offered up by Darwin and Jim that the Whirlwind and some MT models are equal to or better than the Hartzell.

Darwin's evidence is compelling. The only way to settle this scientifically is to switch props on the same airframe or better still a side by side with 2 RVs and then switch props. Times and products change.

We need another Prop fly off
 

Do you have the data you reference, I don't recall seeing it. Here are my sources:

Randy Lervold's excellent test. RV-8 flown with several props Hartzell (older C2YK/F7666), WW 150, WW 200C and WW 200RV. Some of this data dove-tailed off of Vans test (below). Van used some of Randy's data. From Randy's data for the old Hartzell HC-C2YK/F7666-2, it was as fast or faster +/- 1 mph and about 5 mph faster than the WW150 (three blades). This was consistent over cruise and top speed test. The new BA prop is about 3.5 mph faster than the old Hartzell so we can make the assumption that the new BA is faster. Van found the the New BA was faster than the WW 200 RV by +1 mph. I freely admit this is within the tolerance of error. http://www.romeolima.com/RV8/Prop.htm#Test%20results


Van's data: Hartzell BA + 2mph faster > WW 200 RV
(click)


Lazy8: High performance RV-8 flown with the older Hartzell F7666 bladed prop, MT and Aerocomposite. (note there was no doubt that the MT was slower and the Aerocomposite was not faster than the older Hartzell.)
http://www.lazy8.net/proptest.htm


RV-10 Side By Side MT v Hartzell BA (Note: The MT prop plane had a more powerful engine and was at a higher power setting and was just as fast as the stock engined RV-10 with BA prop. Van estimated the power advantage of the MT prop plane (all things being equal and equal I mean prop) than it should have been up 11 mph faster, accounting for the power the hot engined RV-10 was making.
(click)

All we can go on is what we have. Time and again the MT is much slower. Granted we could use more data on the Aerocomposite and WW150, WW200RV and Aerocomposite.

Ross we need more flight test data, two planes, seven props (two hartzell, two WW, two MT, Aerocomp and what ever else), side by side flying. Switch props and fly again. Prop test are not promoted by prop manufactures, especially if they are not as fast. There's nothing in it for them. The reason prop data is shrouded in mystery, hearsay and hard to come-by is the time consuming nature to test them, on planes under controlled conditions.

The most unbiased results we have as I posted above, Randy and Van; Their test are well documented and seem to be unbiased. Granted Van's test used "normalized" data (with Randy's data) based on a common prop, so there may be some error there. However the MT has consistently been shown to be much slower by other sources. Props tend to vary by 1% or fractions of percent, usually, but the MT is full 2 points to 4% slower in some cases, so a MT being faster than a BA, I am skeptical.

The 200RV was only 2 MPH slower than the BA Hartzell (Van's test), so I can see with a +/- error tolerance they may be comparable. Lets do a fly off. Side by side with two RV's, switch props and side by side again. Or even one RV with the switch made. That would settle it. When it comes to speed the 200RV, in my opinion as I have not tested it my self, is probably close or equivalent to the BA.

The more I learn about prop theory as I have studied it, the more I realize its the interaction of the prop with airframe/engine that's the critical factor separating men from the boys. In other words one prop might show a distinct advantage on one airframe from another airframe. One prop may be technically better, advanced composites for example but it's up to the prop designer to tweak that 1% out of it, by tuning it to that engine/airframe and mission. It's analogise to a fixed prop with the proper pitch.

For Example: If you fly with out wheel pants and your fixed pitch prop is pitched properly, than put wheel pants on, your pitch will be wrong. Airframe drag and prop design are intimately related. Same with power. You add more power you need a new prop, IF you want to be most efficient or optimal. Clearly this has to do pitch and not as much an issue with a constant speed prop, but it illustrates that one prop is not good for every airplane. Many props are generic.


There is no doubt Hartzell tuned the BA just for the RV power, airframe and mission by doing not only theoretical calcs but they test flew it on RV's during development. I am sure WW200RV designer (who wrote and article in the RVator about how he designed it) did consider the RV in his design, but not sure he did extensive flight test? I don't know.

There is no getting around the interaction of the prop and the POWER and DRAG of the airplane its mounted to in actual flight. That is why the BA is good, best in my opinion in performance' not only the thin metal blade has advantage, which is theoretically better for high speed, but it's matched to the airframe. Granted not all RV airframes are the same. :eek: So prop test should be done on average RV's with stock engines to super clean high powered RV's. Bottom line what is a few MPH? That is up to the individual and some care some don't.

Let it go!!!
 

Geez George,

Give it a rest. Not everything has to have some "study," chart and graph to make it valid. I explained a side by side fly off and yet you continue to cite Randy's good but solo airplane study. YOU have no experience with WW so why not stay out of the discussion. You've made your point many posts ago. We don't need to read the same stuff over and over.

I think your "engineering degree" is clouding your common sense judgement. Remember that thermometers have degrees and you know where they stick them sometimes. :eek:

George, you might want to search the the MT thread for the posts made there:

Not to get back on topic, but I'll offer my MTV15B (2 blade aluminum blended airfoil prop) to speed test to anyone who already has done speed testing on a Hartzell BA prop. The 3 or 4 airplanes here that are running the (MT) MTV15B prop seem to be running faster than the Hartzell BA's. One guy has the MTV15B on an 8 and swears it is faster than the Hartzell BA prop it replaced. Randy Lervold, are you interested in putting another data point on the chart?

************************************************** *******



Darwin has also posted some flight test data which does not support the idea that the Whirlwind is inferior either.

You choose to ignore information that does not support your preconceptions. I'm willing to consider the results of these tests. I have no idea which one will prove superior so I'll wait for the results rather than speculating.

Just my opinion but your reposting of the same old information over and over is somewhat repetitive. How many times have we seen this before?

Many of the previous tests have been less than scientific although some other posts seem to show speed losses with brands other than Hartzell. The results are far from clear cut in my view.

Maybe we can wait for Jim Ayers flight test data on the MT/ Hartzell question? I'd like to think from Darwin's post that the WW is at least equal to the mightly Hartzell BA.

Test may be upcoming
 

This may happen, in the same hanger where I am building my 6A is a 7 being completed with a Hartzell BA. We have been talking of testing, swapping props and testing again.

Hans

This would be very cool. I know this is a fair amount of trouble to go to, but in the name of science, bigger sacrifices have been made.
;) :)

I appreciate any data you can shed on the subject.

WW200RV Prop is nice
 

Well, I finally got my 200RV on and running. It is smooth, pretty and performs beautifully. I'm still in the testing stages but the leap up in performance from my fixed pitch is eye watering to say the least.
I have had excellent help form Greg Anderson at Whirlwind and also, the folks at American Propeller. Both companies have gone above and beyond to help me.
Since I was installing on a flying 8 I have to have the correct spinner/cowl spacing. I measured and took photo's and sent them in and my prop/spinner combo has 1/8" clearance and looks perfect. They had to modify the spinner backing plate to give me the extra space. Delivery was delayed by 1 day because Greg said the first spinner didn't balance right so they did it again and got it right.
I highly recommend Whirlwind and American Propeller for the customer service. I'm still testing and trying the 200RV, but so far I'm a happy camper.
I have only one question that I will direct to Greg tomorrow. Everything I've read says the 200RV has no RPM restrictions except MAX. The manual that came with the prop recommends not operating continously between 2050-2300. I knew that was true on the 151 but didn't think it was for the 200RV. I'll let you know what I find out.

I say run what you like and feel comfortable with, all propeller manufacturers have there down side or should i say something that people are not comfortable with. Hartzell has changed hubs on the compact design propeller more times than i like to think due to cracking issues, MT has had grease leak issues that have seem to subsided for now, Whirlwind has the blade inspection/change. I have designed blades for experimental flight and we have built many race props in many configurations, i have talked for hours to Gerd from MT about blade designs and how many blades are the most effecient and there are many theories that can be beat to death about speeds in aircraft with different props, like i said run what you feel comfortable with and the only way to test prop differences i believe is to run diff props on the same airframe under like conditions and see what they come out to be and that still is not going to be truly scientific.

James A Dean
American Propeller Service

Opinion: Outstanding
 

Opinion: Bill Koleno; outstanding individual. Knowledge of product type and WW props; second to none. I consider his thoughts and advice as gospel. I consider him a friend.

Opinion: Greg Anderson; outstanding individual. Knowledge of product type and WW props; second to none. I consider his thoughts and advice as gospel. I consider him a friend.

Opinion: Owner of Titan John Williams; outstanding individual. Knowledge of product type and WW props; second to none. I consider his thoughts and advice as gospel. I consider him a friend.

I have owned many other products of this type before, but frankly these guys inherited an issue that could have easily turned into a red herring. Instead, they developed a cost efective method to address it, were able to facilitate the correction quickly and provide a positive customer service experience for even the most difficult customer around.

I was personally treated as if I were the first and only customer of Ttian/WW. John, Bill, Greg and the staff at Titan LISTENED to me and my concerns, addressed and ELIMINATED them. I will not go into the details of how I was treated, but I consider them as friends and would quickly jump in the RV-8 and demo their product anywhere.

Bottom line: a WW prop will be on my RV-10 and next RV-8.

Thanks guys. Keep up the outstanding work!

BTW: Need more vino!

Robbie,

You become so eloquent when fueled by "vino"! But Robbie, how about a little testing before we consider that fix is a done deal? Customer service is one thing, and a very important one, but how about a few flight hours before we start recommending that prop to our fellow pilots. Time in service with no issues is very important for aircraft systems.