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Catto is at it again.

That is very interesting.

How much speed is being gained? Inquiring minds want to know. :D
 
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You've got to get out west more Pierre! We've all been seeign those fences for about a year now..... :)
 
Catto at it again

Pierre,
I'm a new poster, but to reply to you. I saw the propeller in Craig's booth at OSH, they had just removed from the aircraft winning the race. Craig's engineer told of the 6-8 knot improvement, wow!
I looking forward to replace it on my RV8

Light RV8
986 EOW
0-320
Polished

Regards,

Mark
 
Welcome to VAF!

Mark, welcome aboard the good ship VAF.

Those fences remind me of a LongEZE wing.

Also, seems that Paul Lipps was playing around with something like this..
 
Prop

Steve??? Hamer ran a two blade with just one fence on each blade in the '14 Oshkosh race.
I got to talk to him a bit about the prop. He said it was 7 or 8 m/h(statute) faster than the best of the many props he has tried.
Glasair 1TD.
 
I saw fences on a 3-blade in Oshkosh and asked Craig about it. There was one small fence per blade, and they were welded on. Talking to Craig about that was what made the decision for me to go with a 3-blade Catto when the time comes... which should be shortly after he gets that little modification ready for production. Perfect timing, I hope. :)
 
Those fences remind me of a LongEZE wing. Also, seems that Paul Lipps was playing around with something like this..

Paul and Klaus Savier did futz around with these years ago; I have one of Klaus' "Black Bart" carbon props with fences on my LongEZ.
 
I saw fences on a 3-blade in Oshkosh and asked Craig about it. There was one small fence per blade, and they were welded on. Talking to Craig about that was what made the decision for me to go with a 3-blade Catto when the time comes... which should be shortly after he gets that little modification ready for production. Perfect timing, I hope. :)
The Catto props are wood core with carbon and fiberglas/epoxy overlay. You don't weld anything to a Catto prop.
The fences appear to be bonded in place.
 
Catto

Excellent article about Catto a month or two ago in Kitplanes Magazine. Lots of information on the manufacturing process Catto uses.
 
Quite an interesting tuft study. I guess everything gives us a 6-8 kt increase. (SJCowl reference). Sure would be cool to see the after, and just how did that picture get taken? Strobe, mirrors, spinning go pro?

What kind of prop efficiency would that take (at constant RPM) to yield a WOT increase of 6 its? Is it 7% efficiency? Isn't the Hartzell already in the 87-88% efficiency range? Anybody have numbers that confirm this?

I gotta say, the energy and innovation in the experimental world is fantastic. Results really tell the tale.
 
Question to ask is what does it do to the envelope of the prop. It might be great at 2700 rpm than fall flat at 2300 rpm. If I remember Craig had a video of the prop with yarn tufts and the was having some advantages and disadvantages depending where on the prop spa wise, he may have worked it out.
In any case it's a nice concept.
 
Prop

Quite an interesting tuft study. I guess everything gives us a 6-8 kt increase. (SJCowl reference). Sure would be cool to see the after, and just how did that picture get taken? Strobe, mirrors, spinning go pro?

What kind of prop efficiency would that take (at constant RPM) to yield a WOT increase of 6 its? Is it 7% efficiency? Isn't the Hartzell already in the 87-88% efficiency range? Anybody have numbers that confirm this?

I gotta say, the energy and innovation in the experimental world is fantastic. Results really tell the tale.

Many years ago Burt Rutan organized some races at Jackpot NV. They had some t shirts that said "the bs stops-when the flag drops-at Jackpot.
The Hamer brothers are running speeds in the 260 statute range(in races) in their modified Glasair ITD's, both 0 360 powered, fixed pitch. I don't believe there is a Hartzell that can come close to that.
The video on the fence was from a go pro mounted on the shaft where the spinner would usually be.
 
Speed

Dave Anders probably has the fastest four cylinder RV. Tracy Saylor had a very fast RV6, unfortunately that was destroyed in the storm in San Diego a couple months ago. Both had harzell props. Tracy told me that modifying the blades on the hartzell was what allowed him to get above 225 statute.
If you study these airplanes I would estimate that half the performance gain was modifications forward of the firewall.
Dave Anders put the CAFE performance record almost out of reach of any other airplane currently available.
Klaus Savier and Gary Hertzler built props that probably come close or perhaps even equal the best Catto props. Klaus does not build props for others and Gary builds mostly for EZE's.
Catto builds for anyone who has the money.
 
Catto builds for anyone who has the money.

Not necessarily the case. He refused to build one for my project on the grounds that a fixed pitch prop was not the safest combo for it. He was right in doing so. Since then I have contracted GT Propellers in Italy to design and build an electric constant speed propeller.
 
I talked to Craig about it at OSH ...

When I asked him if the fences made much difference in performance .... Craig got this HUGE smile on his face and said something to the effect of, "oh my gosh yes!". He went on to say that the magnitude of the performance enhancement even surprised HIM. He was really "bubbly enthusiastic" about it. I have one on my wish list. :D:D
 
Prop

I should have said apples to apples-same cubic inches. The Hamer airplanes seem to be running as fast or slightly faster with 0 360 parallel valve as Anders was doing with angle valve and hartzell. As the power increases the constant speed becomes more favorable.
Of course the Glasair has much higher stall speed than RV.
Also I think Ander's engine was much more radically hot rodded than the Hamer Brothers engines.
 
The Catto props are wood core with carbon and fiberglas/epoxy overlay. You don't weld anything to a Catto prop.
The fences appear to be bonded in place.

Well aware of the materials used... It was attached to the metal leading edge. It looked welded to me, but I didn't ask about that specifically.
 
Prop

I don't think the Hamer airplane had a metal leading edge. The metal leading edge costs a bit of speed and I don't think the Hamer brothers would compromise on speed.
 
I should have said apples to apples-same cubic inches. The Hamer airplanes seem to be running as fast or slightly faster with 0 360 parallel valve as Anders was doing with angle valve and hartzell. As the power increases the constant speed becomes more favorable.
Of course the Glasair has much higher stall speed than RV.
Also I think Ander's engine was much more radically hot rodded than the Hamer Brothers engines.

Its worth noting that the actual output of modified, parallel-valve O-360s has been reported to exceed 220 hp in some cases, so the parallel valve/angle valve distinction may not be all that significant. Also the Glasair I has a wing area of 81 ft2, compare to around 110 ft2 for the RVs (more drag with the RV wing). It also seems likely that Bruce and Steve Hammer are turning significantly greater than the 2700 rpm restriction on Hartzells.
 
Its worth noting that the actual output of modified, parallel-valve O-360s has been reported to exceed 220 hp in some cases, so the parallel valve/angle valve distinction may not be all that significant. Also the Glasair I has a wing area of 81 ft2, compare to around 110 ft2 for the RVs (more drag with the RV wing). It also seems likely that Bruce and Steve Hammer are turning significantly greater than the 2700 rpm restriction on Hartzells.

Alan, I don't think Bruce or Steve swings a Hartzell. Pretty sure they are both FP Aircraft.
 
power

that power would someones fantasy. More realistic would be 195 hp for 0 360 parallel valve. Of course if you can live with 25 hour tbo 250 hp is possible.
 
Quite an interesting tuft study. I guess everything gives us a 6-8 kt increase. (SJCowl reference). Sure would be cool to see the after, and just how did that picture get taken? Strobe, mirrors, spinning go pro?

What kind of prop efficiency would that take (at constant RPM) to yield a WOT increase of 6 its? Is it 7% efficiency? Isn't the Hartzell already in the 87-88% efficiency range? Anybody have numbers that confirm this?

I gotta say, the energy and innovation in the experimental world is fantastic. Results really tell the tale.

The aluminum extension appears to be holding a GoPro. According to the web site......

"In 2013 Catto Propellers began to develop a method to record the dynamic air flow of a propeller in flight. With a custom mount made by Saber Manufacturing and a vacuum formed carbon fiber case to house the GoPro, we were able to maintain a live feed on the propeller aerodynamics. The GoPro Hero 3+ with 60 frames per second, 1080p, provided a real time visual throughout the flight profile that allowed Craig Catto to improve the propeller efficiency by actively notating where it is possible to reattach flow and modify the airfoils accordingly, ultimately improving the performance of the blade, in all aspects."


Catto_Prop_Fences.jpg


I wonder if the GoPro warranty would cover any damage? ;)

Pretty amazing stuff. Got to love experimental innovation. It never ceases to amaze.
 
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Excellent article about Catto a month or two ago in Kitplanes Magazine. Lots of information on the manufacturing process Catto uses.

Unfortunately, can't read it. "To continue reading this entire article you must be a paid subscriber."
 
Color me skeptical; 6-8 knot increase in cruise or top speed just from this?

Not dissing Catto or his engineers (I have a 3-blade resting on the dining room table :rolleyes:) but from long engineering experience in another field I'll wait for actual before-after field measurements before I get excited.
 
Unfortunately, can't read it. "To continue reading this entire article you must be a paid subscriber."

Pay Up and Read - you won't find a more satisfying read each month than Kitplanes. No affiliation, just a satisfied reader. It is everything I wanted from EAA but didn't get.
 
Alan, I don't think Bruce or Steve swings a Hartzell. Pretty sure they are both FP Aircraft.

You are correct. What I meant was that people flying with Hartzell props are more likely to observe a 2700 RPM limitation than those with wood/composite fixed pitch. I'm guessing that Bruce and Steve don't limit themselves to 2700 when they're racing.
 
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