More: the initial takeoff thrust is very good, but not much better if any then the heavier 72" 3 blade Warp, (12 lbs ) but better then the KIEV. But it quickly outperforms the Warp and any others I've tried once off the ground and actually flying, especially high up, it's a monster up there.

Enough high up, down in what is more common elevations for me, anywhere from water ski height (had some dusty tires that really needed cleaning) to a few hundred, I found that pretty major alt gains could happen with just a slight pull on the stick, and not just a blip but sustained, no increased throttle needed. So much so it's almost like a constant speed prop, just set the throttle and forget it (so I've heard, never flew one). If nothing else it lowers the already tremendous cockpit work load I have, fooling around with the SAT radio, making cell calls, taking pictures, I can't be fooling with the throttle all the time. I noticed this before after the Zipper mod, now this guttier prop is working with the increased torque, the two are teaming up, and I mean up

According to another Rotax geek, a very experienced one, it is very quiet, like REAL quiet, and the different tone makes it sound, at least to my ears, more like a conventional aircraft engine. Probably the two blades accounts for that, a lot of Rotaxs use three blades and i think we get some kind of resonance or something with the exhaust pulses that give them a different then traditional "real airplane" sound. IF I put my SWISS muffler back on, this thing would be scary quiet, and I am considering it, I just need to weld on a new stub to put it back in service. The needed loose/un clamped flex exhaust tube connection at that point (to allow a little movement) after over 1000 hrs wore the stub down. Part of the reason it's quiet is the reduced rpm's I can fly at.

I have 265 hrs on the Zipper mod now, this prop seems to compliment it's performance gains with even more performance gains. All while losing weight and with no more complexity like a turbo.

Kind of looks like my 180 with the two blade MT prop. You say it is not as smooth, will it be bugging you after a longer flight?

Is there a metal leading edge? The rain would eat it up?

180Marty wrote:Kind of looks like my 180 with the two blade MT prop. You say it is not as smooth, will it be bugging you after a longer flight?

The Harley analogy holds true I think, though I only rode a Harley once, I had a lot of hours on a Honda Goldwing. Both are good, just in different ways, though the Goldwing was "smoother". I flew 4.5 hrs Sunday, no bugging involved, got used to the different feel real quick. It's very similar to the 78" 2 blade Catto in that regard, or for that matter the original kit supplied Sensenich 72" wood 2 blade prop. You're moving more air with fewer prop pulses, so the pulses (if that's even the correct terminology?) are more noticeable. It is really kinda enjoyable, just different, it makes me want to wear black leather next time I fly, and maybe take the muffler off to make more noise, to take the Harley analogy a little further. The performance overshadows all else, and I'm getting better performance at a lower RPM and a cooler sound.

gbflyer wrote:Is there a metal leading edge? The rain would eat it up?

Supposedly this has some type of extra LE protection, under the top surface, I sure can't see any metal. I'll probably never find out as flying in rain in my area, for me anyway, is super rare. Time will tell, I'll reserve judgement on that issue, good question.

I'm working with Hal to get him a site for the zipper kits. It might clear up any questions you might have with what is available and what the specs are for each version. I was confused when I first got jealous of Simko/Big John et al.

http://zipperbigbore.com/

I have my engine back from Hal with more horse power but for some reason I plane is now in a thousand pieces because it was a long winter and I decided to get creative.

Also, the site isn't finished yet. The testimonials section isn't fleshed out at all. They are just place holders and I hope nobody gets sued over it.

We just learned today the gearbox needs to be readjusted for these longer props we are all liking so off to MS they go. Good news is Morris gets them done quickly.

That lightweight Prince seems to be on a par with the Kiev as far as I can tell so far on startup and shutdown. As compared to the Warp, which felt like it was really working things. I'll report back if I have any issues with the gearbox, but I don't plan to mess with it as of now. I will be on a heightened alert however. I'm liking the Prince more and more, I find myself at 4800 rpm or less more often then not, at 75 to 80 MPH at 6K alt. 3.4 to 3.7 GPH. Pretty good I think for a fat tired Robert Geared S-7. Took off from Blackfoot a couple hours ago, and for the first time held it level while it wound up a bit and then gently pulled and wham I was almost 2 K FPM ROC and not just for a second or two, before it settled down to way over 1,000 FPM. I need to get down to sea level with this setup, and compare apples to apples (?) I think I just made an excuse to hit the coast. Or maybe the panhandle of Idaho anyway, pretty low up there (get on the Snake in Nez Pearce County, 710' ASL, I'll head over that way at some point.

I'm pretty interested in you prince prop thoughts.
I got the Superstol finished and home a couple of days ago on a Kiev prop. I'm running a stock 914 and taking off at 5,000 altitude. I actually like the Kiev pretty well, it sure is smooth but you have me hungering for more.
Any idea what pitch a guy would want on a prince with the 914?
Anything else I should be looking at... I'm pretty new to the rotax thing

Blu wrote:I'm pretty interested in you prince prop thoughts.
I got the Superstol finished and home a couple of days ago on a Kiev prop. I'm running a stock 914 and taking off at 5,000 altitude. I actually like the Kiev pretty well, it sure is smooth but you have me hungering for more.
Any idea what pitch a guy would want on a prince with the 914?
Anything else I should be looking at... I'm pretty new to the rotax thing

Yes indeed, the 3 blade KIEV is real smooth, and a good performer. But with this Prince, I have a whole new airplane. The other day I was a few valleys over and needing to climb from 5K to a bit over 8 to clear the ridge line, the amount of excess throttle left over, unused and unneeded, is really something. I just kept the ROC at about 3 to 400 FPM and following a canyon dirt road kinda corkscrewed my way up and over (no wind to worry about), really just loafing the engine, with the rpm about 5K. The ROC/power in reserve, there if needed is way different then before. The simplest way to put it is I use the throttle less then before, seems about anytime any speed I can nudge the stick back a bit from level flight and initiate a climb, and then maintain that climb for however long it is needed. Effortless is the impression. I've had it into some short places now, some familiar and some new, and it does better then the KIEV in that initial push to get rolling also, much better.

You'd probably be fine with the prop I have, talk to Lonnie. As noted, I am not over speeding it at WOT, I think he nailed it pretty good, and the light weight is a bonus. 15 hrs+ now on it.

Wow that sounds pretty tough to beat.

What static rpm are you getting and at what elevation?

I just sent in my request to prince so i guess im in. Just hoping i can nail the right pitch on the first try like you did.

Am i right in thinking that in your experiance this is the best prop for the rotax even over the Catto?

I'm a fan of Catto and Just aircraft is running them on all their planes and feel they out preform the kiev but you experiance has me thinking i can have my cake and eat it to.

I'm a little worried that the 78x50 he is building for me will be a little too much pitch…

(912 Zipper 105 hp.)

I'm turning less then 5200 static, more like 5080 /5100. But, I never have done a just sit there full power static run up, more a glance at the tach as I start rolling. Then things happen pretty quickly and I look out in front.

Today, another couple hours of fooling around down low with a little high, 4750 RPM and 75 ind. at 6K. Leaned out it 3.2 gph, not leaned it was 3.9 gph. A neighbor who is familiar with my old setup, gave me a sound check after I texted him I'd be flying over. He's got some gen av experience also, he says it sounds like a "bigger" airplane now. The overall noise level is higher,as I also have the Swiss muffler off, his wife said she could hear me coming, not so with the old setup. I feel phase two of the Swiss muffler is imminent. Comparing it to my old setup is a little unfair, as it was the quietest thing plane in the air. Bragging yes but I was told that many times! It will be interesting to see how the Swiss muffler interacts with the Prince.

So far, the Prince is a stronger performer then the 2 Catto's I tried, 1 being under pitched and the second being more of a decent climb and good cruise prop but slow acceleration. The Prince is several lbs. lighter also, a pretty important factor for me anyway.

Right offhand AV8R, I'd think you'd be pretty happy with what I have, we have the same engine anyways. Look at it this way you have lot's of time to think on it, one benefit of his /manufacturing/delivery times!

The plane won't fly until this fall at the soonest, anyway.

So I order up a Prince prop today
Lonnie sure is a nice guy
It's a 80"x44
Hope it's all I'm dreaming of

Av8r3400 wrote:I'm a little worried that the 78x50 he is building for me will be a little too much pitch…

(912 Zipper 105 hp.)

I spoke to Lonnie today and he agreed. It was changed to 48" pitch. He told me that it is as far as having the core glued up...

I just thought I would throw in an update on the zipper bigbore kits. Hal Stockman and BTV came down to Llano and cleaned up in the STOLE contest with their high compression zippers. Hal had the shortest Take off beating out a pair of tricked out Carbin Cubs. It really is amazing The performance He is getting out of these engines. His S7 is about the same weight as my short tail with 80 horse, but with his 116 horse he was getting off in half of my best effort of 198 ft!!!

Now you are making me wish I would have bought the high compression set instead of the low compression kit!!!

WW, don't sweat it, you'll be happy with the setup you have ordered. Hal also has Oratex on the wings, so a bit lighter, and small tires and stock gear. It doesn't surprise me at all he beat the CC's off the line, yet another example of raw horsepower losing out to lighter weight, as in last years Valdez results.

Good idea to blab those Llano results up on this thread! Hal did good.

I put my Swiss muffler back on. I took it off in a frenzy of weight saving I went on last fall. It cost me nothing to lose the weight, and only took about 5 minutes. Since then I for the first time have an all digital EIS with EGT, fuel flow etc., and am much better instrumented as to what difference it makes, if any.

I first rebuilt the tailpipe (as good a term as any,) it's the 1.5" dia. aluminum stub that sticks out and also projects into the muffler for a couple inches. The automotive flex muffler tube must not be clamped to the muffler, it's just a slip fit. It IS clamped to the other end. In time, like well over 1000 hrs, it wears the tailpipe down, during this same time period the flex is replaced several times, as needed. Less then 10 bucks, and about 5 minutes to replace the flex. to replace the tailpipe, I simply cut off the end of the muffler with a skinny wheel, losing about 3/8" in effective length, at this rate I'll need to build a new muffler around 2075. Then I ran it down to my aluminum welder, and 40 bucks later for labor and material I was good to go for another 1400 hrs. While I had the inside exposed, I was happy to see the muffler packing inside was in great shape, no need to mess with that.


After this pic was taken, I chamfered the tailpipe inlet, theoretically making the exhaust gas enter it more smoothly.
Then some new mounting brackets, using existing tabs under the floor boards, so not centered, I just offset it as required.
The finished product, and remember, I can't see it when I'm flying! And, it is almost identical to the first setup, which worked fine for 1400 hrs, never fell off or caused any trauma to the stock Rotax muffler system anyway.
Total added weight is 6 lbs 4 ozs. I flew for an hour today and I MAY have lost 40 rpm static (according to the EIS). Then again, today's WX was quite different from the last time i checked the static R's, a few more flights should nail down any loss of rpm, but as of right now, I'd call it 40 at most, maybe none.....

The reason I put it back on is the Prince Prop makes a bit more noise then the Kiev, but the tone of noise it makes is "way cooler", a deeper more real airplane sound, almost a radial engine sound, according to a neighbor who would know. I got curious as to how the BigBore/Prince/SwissMuffler combo would sound, plus I frankly have enough performance to give a small bit up, though that may not be the case. I certainly couldn't tell any difference today, still gobs of climb, even at altitude and much less then full throttle, no real change in the EGT's, and for sure quieter. I need to let another S-7 pilot fly it, and do a fly by for me, that may happen in the next couple days, but I am happy, again, knowing I have made the plane as quiet as possible, I can't count how many times I was told "that's the quietest plane I've ever heard", or, "We didn't hear you taxi up", or "fly over". Coming up on 300 hrs on the BigBore, just changed the oil (every 50 hrs) and all is well. One last thing about the Swiss muff: it keeps the bottom of the cowl cleaner!