I understand WW actually gets a prop out to a customer in a reasonable amount of time, is that correct? And, that time is not measured in (many) months, do I have that right? Wow, what a concept, all I can say is it's a good thing I really like the Kiev and don't really mind flying it while I wait, and wait, on the others. I knew this going in, but they are giving slow a whole new meaning. The flip side is, they must be worth it, we'll see, someday, hopefully this year.

Only takes about a Week plus shipping delivery time to get a Whirlwind. Did more testing Yesterday and thus far am very impressed and I don't expect I will change my mind.

I have my heart set on a two blade fixed pitch, the explanation that Catto gave in that recent Kitplanes article on why a properly designed fixed pitch prop, with the thrust/lift optimized along the entire blade as opposed to the inherent compromises of a grd adjustable, made perfect sense to me.and at least on the Prince those tips are just flat wicked The Prince and the Catto, but especially the Prince, also had a totally different, and very pleasing, tone to them. Other then that I'd go with the 75"WW, or the 75" Kiev (not available when I bought my 70") if I wanted to wait several months It's really good to know the WW are pushing a good product out the door, and in a prompt fashion, wow.

Tom,
When I ordered my WW, which was a couple of years ago, I think it took 6 weeks until it was at my door. More then was quoted but I am real happy with the prop. Having said that I am lusting after a set of 75" blades and the reply was: "The RW75 blades are $450 each, so a set of three would run $1350. We have about a 1 week lead-time." This quote was dated Sept.24th. I don't have any idea what the Catto or Prince prop for the Rotax sells/will sell for. I will probably stay with the WW since I already have the hub, backing plate, and spinner so all that is required is to replace the blades and pitch them to my needs. If the others are similar in price I may just as easily change my mind.

Way back when, I was going to buy the Kiev from Ted B. but after reading comments about long waits on replacement parts I hesitated the purchase before I had read an article in Kitplanes about the Whirlwind. Actually spoke to the author of the article and posed many questions to him that he answered giving me the nudge to get the WW. To me the Kiev and WW appear to be very similar profiles, if they are or not I really don't know as I am just going from my visual inspection of each.

We had the 75" WW blades shipped to AK via US Postal in a week. Uses the same hub. $450 per sounds about right.

I've also been watching this thread with interest in that i'll be using a 105 hp low compression Zipper in my Kitfox IV build in progress now.

I have an Ultralight IVO, electrically ground adjustable ( ), for it now, but am considering something else.


I'm really looking forward to hearing about the Prince and Catto options...

Av8r3400 wrote:I've also been watching this thread with interest in that i'll be using a 105 hp low compression Zipper in my Kitfox IV build in progress now.

I have an Ultralight IVO, electrically ground adjustable ( ), for it now, but am considering something else.


I'm really looking forward to hearing about the Prince and Catto options...

I'm curious why you would change from an inflight adjustable to a fixed pitch, or ground adjustable.

The ultralight IVO is incapable of handling any more than the stock 80 hp, so a change is required, anyway.

As to the fixed pitch versus ground adjustable, I would refer you to the recent article in Kitplanes magazine on Catto and his prop technology.

gbflyer wrote:We had the 75" WW blades shipped to AK via US Postal in a week. Uses the same hub. $450 per sounds about right.

Same hub....same hub as the Kiev? Or same hub as for the smaller blade WW? I seem to remember that WW fits Kiev hub, that right?

Same as shorter WW. I don't know about Kiev.

I know Warp & Whirlwind use same Hub.

gbflyer/Big John,
Either of you and any more performance numbers you would care to share? I am still in limbo on ordering another prop.
Simko's "any day now" on recieving the props he is testing, has probably got me as antsy as he is. All these are reason's I haven't ordered anything yet. Heck, my Zipper'd S7 with the current 3-blade Whirlwind is already great and all I probably need but a guy is also searching for more.

The 75" WW I would think to be over sized for the 105hp Zipper, The 70" should do fine, I lost a slight amount of cruise with the 75" but again I pitched it for climb. At about 1200 lbs and msl of around 3000' I see consistent climb rate at VY 75ish mph of 1100-1200' min. The old 70" warp was around 800-900' min at same weight. In flight comparison with flying buddies it performs significantly better than before. Power on stall testing went as follows.
Warp 70" angle of just over 30 degrees speed 36mph, DA 5000', still climbing at 200' min when it would bufit and stall.

WhirlWind 75" set at 17.25 degrees. Altitude 6000' DA, Climb angle over 35 degrees indicated 30-32 mph indicated climb rate 500'+min no total stall just bufiting, didn't have the nerve to increase angle on that test.

Just increased the pitch to 17.5 degrees to increase the cruise slightly with no noticeable loss on climb.

Thanks Big John. Could you please explain why you think the 75" would be too much for the 105hp? I am no aerospace engineer (but my son is one) and understand it may be a big long for my engine but with my current prop pitched for 5300+ static, I can very easily over rev it. Hal stated running up to 6,000 rpm. I was advised this is not a good thing to be doing on the 912 but I was straight and level when I firewalled it. Yep, easily hit 6k rpm. I would think with this ability I would be able to use the 75" prop. Do I really need it...no. Guess I should just use that $2,000 for gas.

WWhunter wrote:Thanks Big John. Could you please explain why you think the 75" would be too much for the 105hp? I am no aerospace engineer (but my son is one) and understand it may be a big long for my engine but with my current prop pitched for 5300+ static, I can very easily over rev it. Hal stated running up to 6,000 rpm. I was advised this is not a good thing to be doing on the 912 but I was straight and level when I firewalled it. Yep, easily hit 6k rpm. I would think with this ability I would be able to use the 75" prop. Do I really need it...no. Guess I should just use that $2,000 for gas.

Only basing the length on what WW recommends the 75" for 114hp+. I am sure the 106 could pull it but at less pitch which would slow your cruise, they also make 72" & 73" which may be better, I would call WW and ask them. I can still pull 5400 static and about 5900 max rpm level flight with the pitch set at 17.5, WW recommended 17 degrees for 114hp for 5800 level flight, Now this all changes some with aircraft.

To further confuse the issue....I have flown 9 hrs now with the second gen CATTO, and he fixed the problem of the first one: over revving at much less then previous top speed with only a modest increase in climb as compared to my 70" KIEV. This one is a real cruiser, 3 to 5 mph faster top end then the KIEV, and at my normal cruise speeds uses over 100 less RPM.

But, it's a dog in climb, sort of, not as good as the KIEV anyway, or the first gen. Obviously over propped now, my static is only 4980 rpm, and at my best climb speed of 60 it's still only 5200 or so. It is not what I want, too big a sacrifice in the climb, and as compared to the smooth running 3 blade KIEV, you can really feel (and hear) those big wide chord 2 blades slapping the air.

In the usual time frame of dealing with most prop makers, I emailed the KIEV US supplier a week ago, asking if the 75" blades fits the hub I have now for the 70", no answer yet. It's been over 2 months since I traded off the first gen Prince prop, and put my request in for a gen 2 prop, and after asking for a heads up last week am being informed another 2 weeks should do it. It was mid April when I initially ordered the first Prince, so 6 1/2 months by the time I get the second, maybe. I have heard OK, and even pretty good things about the WW, but better things about a properly set up Prince, and that is where my hopes now are. The first gen was the best over all performer of anything tried yet, and had the best sound also, as a bonus, even over pitched like it was. I expect the second one to kick butt, period. The bigger KIEV , using my old hub, would be a cheap (?) backup prop, and BTW the KIEV is the lightest and installs the easiest, no crush plates or hub bushings, just bolt it on.

To further confuse the issue some more.... a couple days ago, cruising back from a great little local fly-in, at about 8500', I found out that I was climbing 800 to 1000 fpm clear through 10,000', real sustained. About 70 degrees OAT, that Catto was pretty damn good up higher in the thinner air.

Over 150 hrs now on the BigBore, and all is well All of it on regular mo-gas, and most of that E10 no less. I've been waiting on the local rapidly dropping mo gas prices to somewhat bottom out, and then I'll buy my clear gas bulk tank load of around 400 gallons to get me through the winter.

75" WW is not too long for stock 912 at sea level. Can't say for sure anywhere else. 17.5 pitch, 5800 WOT (have not checked static, scares me), about 95 cruise at 5000 rpm with 29" Airstreaks and monster gear. Climb 1100 fpm at 65.

Wow! Thanks everyone! Lots of info that is greatly appreciated.

I am getting 100+mph (5400 rpm) with my 3-blade 70" WW. I am also on 29" AkBushwheels with the stock gear. Haven't nailed down the numbers preciesly yet due to a couple of reasons, It's been a typical windy fall so not much flying, also, I somehow lost my memory card for my GPS so I am only going by a two way flight averaged via the ASI. I have seen as high as 114 on my handheld GPS but forgot to look at the speed on the 180 degree part of that flight.
I am also in the process of breaking in the Zipper kit so things aren't consistent enough to get firm performance gain data.

Flew to Elko before the HS Fly-in for Hal to install my big bore kit.

I had 100 hp 912 and went with the 114 hp high compression kit. I have the 75" WW STOL prop.

Before install static rpm was 5000 and after 5400 with no pitch change. Takeoff and climb performance is noticeably better. Hard to run absolute tests due to atmospheric conditions, but I think I have gained 300-400 FPM in climb.

The only problem I had is my engine didn't run cooler(as others have reported) with the new cylinders. The plane could be flown but CHT and oil temps quickly went into the yellow on hard climb. My engine had always run on the warm side. I had previously installed a larger oil cooler to control oil temps. I was hopeful the big bore would help my cooling. We ended up installing a 914 radiator to get CHT under control. Temps are now good, but I have only flown in 75-80 degree air so I am a little concerned I may have issues next summer.

Also installed a HACman leaner. On my way back to Texas I cruised at 5500 rpm trueing out at 115mph and burning 4.2-4.6 gallons per hour depending on altitude.

All in all I am happy with the performance increase.

[quote="BTV"]Flew to Elko before the HS Fly-in for Hal to install my big bore kit.

I had 100 hp 912 and went with the 114 hp high compression kit. I have the 75" WW STOL prop.

Before install static rpm was 5000 and after 5400 with no pitch change. Takeoff and climb performance is noticeably better. Hard to run absolute tests due to atmospheric conditions, but I think I have gained 300-400 FPM in climb.

The only problem I had is my engine didn't run cooler(as others have reported) with the new cylinders. The plane could be flown but CHT and oil temps quickly went into the yellow on hard climb. My engine had always run on the warm side. I had previously installed a larger oil cooler to control oil temps. I was hopeful the big bore would help my cooling. We ended up installing a 914 radiator to get CHT under control. Temps are now good, but I have only flown in 75-80 degree air so I am a little concerned I may have issues next summer.

Also installed a HACman leaner. On my way back to Texas I cruised at 5500 rpm trueing out at 115mph and burning 4.2-4.6 gallons per hour depending on altitude.

Sorry I missed you at the fly-in, you and the other Zipperheads! You had the furthest to fly, no? Anyone from further??

This morning, in my coldest flying yet since the conversion (30 degrees) My head temps were right at 143, and the oil 173. I am getting a little concerned for my ski flying this winter, as in too cool, I already have a means to bring the oil temp up (cockpit adjustable shutter) but may need to tape off some cowl inlet to bring the CHT up, for more cabin heat if nothing else.

The second Catto prop is kind of growing on me, after I had somewhat given up on it. Though somewhat of a dog on initial acceleration (expected with that 4900+ static), once off the ground it really shifts into overdrive, and climbs out quite well. It took me a while to get a handle on this, the tepid roll at first then followed by really good performance once about 40 mph is reached, as in 1,000'+ ROC at 4500' elevation, and it just keeps doing it, sustained, going up that is. Coming home this afternoon:5020 RPM and 88 mph cruise ind. at 4.0 GPH at 7K, with higher speed easily maintained if needed but I had time to kill. As I said, I really like the way it cruises and effortlessly climbs at any speed, without adding throttle just nudge back the stick and the Zipper torque and that wide chord prop really team up, just a hard to describe experience from the KIEV, a different feel. With a passenger the other day, and with one notch of flaps and at 4000 rpm and 50 mph, we were doing some aerial pics over town, and the damn thing kept climbing I was going to take it off and put the Kiev back on for the next weeks, before the Prince gets here, But now I think I'll keep it on.