Looks like a JATO bottle! I like it.

Got my prince prop on the super stol today
Only got in 10 minutes of flying, but so far wow!!

Blu: I REALLY like my Prince, 25 hrs now and the amount of reserve throttle I always seem to have, even while climbing (especially while climbing) blows my mind. You are going to love that thing, let's see some pictures!

Swiss muffler: I flew over a herd of horses yesterday, and their non reaction was gratifying, and what I saw all the time when I had the Swiss on before. A non scientific test for sure, but I was pretty low, (LOW) and they didn't even look up. I appreciate their participation in acoustical testing. Next will be enlisting a few drift boat fishermen on the Snake River, paying attention to reactions, if any, on the ground or water tells me a lot. For the few months I had the SM off the plane, I definitely noticed an increased awareness of my passing from those below.

OK, so I finally caught ahold of this thread and read through it all. I was pretty sold on the 914 turbo as I contemplated my potential S-7 build, but after reading through your experience courierguy, i'm thinking this might be a better way to go. It looks like you are dealing with about the same altitudes I am and it's working good for you. Thanks for posting this, if this deal comes together, I may very well shamelessly copy your set-up

Tom,
Other than the HACman fuel leaner, did you change anything in the carb after the Zipper mod? Mine has gone from 80HP to 95 (?) to 105HP with the same kit as you. Just got back home after my winter solstice and my engine is not runing correctly. Had to replace the voltage regulator/rectifier also. Removed the plugs and they are very black, ie. running rich. I think this engine is going to be the one that drives me NUTS (nuttier than I already am).

WWhunter wrote:Tom,
Other than the HACman fuel leaner, did you change anything in the carb after the Zipper mod? Mine has gone from 80HP to 95 (?) to 105HP with the same kit as you. Just got back home after my winter solstice and my engine is not runing correctly. Had to replace the voltage regulator/rectifier also. Removed the plugs and they are very black, ie. running rich. I think this engine is going to be the one that drives me NUTS (nuttier than I already am).

Nope, didn't change a thing. My plugs look great also, I checked.

I don't want to diss the 914's, and won't, but I do like the simplicity and the light weight of the setup I have, the cool operating temps are also a plus.

I have been wanting to make a long and high flight, to really see what the Zipper Big Bore/Prince Prop/HackMan Leaner/Swiss Muffler combo could do. I now think of all 4 mods as if I had planned to end up here all along, rather then just randomly keep changing things until I was happy or ran out of money, or both. Sure I fly a lot but it's all local, maybe an hour out somewhere, and an hour back. Plus with doing a lot of fooling around on the way, getting any kind of handle on my fuel burn was mostly guess work.

To be as accurate as possible, I filled my wing tanks via the method I use while "on the road", I use my underseat transfer pump, and pumped just until a little rocking had a few drops of fuel dribbling out the under wing vents. Then I filled the 6 gallon ferry tank, just an outboard motor aux tank strapped down in the aux cargo area where the pass. seat would go, right underneath the folding mountain bike. I also loaded my usual XC and camping out gear, probably close to gross.

The mission initially was to fly to the lowest spot in Idaho (no reason, I just wanted to) and while doing what passes for my flight planning, I noticed a direct route to Lewiston from my place would take me within a few miles of Borah Peak, Idaho's highest point. The mission quickly was modified, why not do the highest and lowest points, and do it non stop?

I had close to 100 miles to get up to Borah's height, so I did a nice slow cruise climb and once getting close to the Lemhi's (the biggest and most bad ass range in Idaho, eat your heart out Frank Church) I was only at 10K. I was on the shady side (early morn, so west side) and quickly realized I needed to be on the sunny side, what the hang glider pilots call the "back side". I have never flown the length of the Lemhi Range right down the middle, and it was like flying over the moon. Super steep, super rocky, and mostly still snow covered. Scenic as hell also. Unlike almost all of the jagged peaks, I did spot one smooth (appearing....) ridge that appeared to be landable, at 11,500', and decided to save it for when I get bored someday Just thinking of landing it makes me giddy.... Anyway, I continued the cruise climb and nicely timed it so by the time I got next to Borah I was here:





Later I realized, though I ended up at a bit over 13K, and Borah is "only" 12,665', I never did fly directly over it, just along side, it seemed disrespectful somehow, and frankly it intimidated me a bit, OK, a lot. I climbed it a few years back, and had somewhat an attack of vertigo at one point, kinda dizzy and spooked by the exposure, it passed but I never forgot it.

I then set course straight for Lewiston Id., but stayed above 12K. This route took me right over a lot of the familiar Frank strips, and though tempted to drop down and play a bit, I kept to the flight plan, but did keep myself entertained listening to the radio chatter. A while later, after a 12,000' descent, about 7 miles from the Lewiston control tower, I saw this:



I had hoped to land a gravel bar (and could have gotten this pictured altitude another few feet lower) but on a low (and what felt like in slow motion, what with that thick low level air) flyby I saw it was overgrown with 4' tall brush. I did land this ridge a thousand feet over the Snake about 30 miles away, after 5 hrs in the air I had a hydraulic problem, and quickly solved it once on the ground:


From there I had to climb back up to 6 or 7K, and then I first landed New Meadows, but took off again and landed at McCall. The Pancake joint across and the down the street a ways was jam packed and after getting a seat and then not being served for 10 minutes, not even coffee I got up and left. Walked right by a gas station also, something I rarely do when XC. I did get a great iced coffee drink and a bagel at a roadside stand (no waiting), and took them back for an inflight meal. Another bit of flying and another climb back up to 6 K and I landed at Emmett Idaho, where I signed in for the courtesy car and taking my 6 G. aux tank, two BushBags, and two 2 G. jerry jugs, came back in a few minutes with exactly 20 gallons of mo gas. Premium, as Emmett is pretty low, 2362', at my more usual 4500' and above I burn regular, and yes it was E-10, I burn that also.

I started my transfer pump, and at first I was thinking I may not get all the fuel in the plane, but I did just barely. Though the usual wing rocking had to get pretty vigorous to get any fuel out the vents, I was filled back up but if anything maybe half a gallon less fuel then when I started. Now to do the math, the hour meter showed I had been flying a total of 7.2 hrs, including taxiing but that was very short duration. Any Lycoming or Continental pilots stop reading NOW..... to continue will just piss you off. My fuel burn, and I will stand by it's accuracy +- 1/2 gallon, works out to be 2.778 GPH Mission accomplished, using the Leaner, turning that big Prince prop slowly, not being in a hurry ( the GPS showed 80's mostly, with some 90's, no wind to speak of) really paid off. Oh yeah, after that 7.2 hrs airborne, I still had an estimated (using the fuel burn of 2.7 GPH and the remaining fuel onboard of 15 gallons) 5 hrs of cruise with 40 minutes reserve. In fact it turns out I could have made it home (which I did, later that day,another 3 hrs) without the Emmett stop! I was amazed, I was hoping for 3.2 or so at best, I keep looking for errors but can't find any. Having a fuel flow indicator was critical, as it showed how almost no changes in airspeed gave large fuel savings. A little faster took more fuel then it was worth. Though coming back into my place, I saw a big cell right over "my" mountain range, the only WX all day and it's right over my strip looking to go critical any minute. I texted a neighbor when I was 8 miles out and he kept me informed, running into a gust front on the wrong side of the 9K+ ridge I'm below is not good, done it once. So pretty much firewalled it and got it down and in the hangar 15 minutes before the storm hit, which I watched from the deck with a cold beer

310 hrs now, and since the Swiss muffler is back on, the belly stays spotless. I love this setup, cheap to fly and gutty, quiet also.

Great report!!!! Been awhile, but I used to eat in the Pancake house quite a bit.

CG, it's probably poor form to ask, but here goes: Have you flown this setup with smaller tires on, 850s or 800s?

I'm just wondering. I have my Zipper kit on the shelf and am expecting a 78" Prince any day. I'm trying to estimate what type of cruise I will get from this configuration.

Not yet, but I'll be putting the smaller tires on with winter's approach so I can put the wheel skis on and if I get a chance I'll probably make a flight or two on small tires only/no skis.

Just passed 400 hrs since the BigBore mod, and all is as it should be

Just finishing up my 114hp zipper kit on my s6-s with a 912ULS!!!

Should start it tonight. Going to get it fully warmed up, then let it cool off and re-check torque values etc. (replaced oil lines, coolant lines, fuel lines etc. while I had it tore up so I need to look it over a few times before putting the cowl back on).

Added a degree of pitch because I was a little high static RPM after adjusting it the other day... running a 68" nickel edge tapered warp drive for now- planning to go larger but I need more ground clearance first. Hopefully flying tomorrow!!

I live at 6600ft elevation, so the extra power is going to be very welcomed!

I like the way you already have your avatar blurb updated! Let us know how it goes.......

If you want to burn more fuel, you can. If you want to burn the same or less you can do that also. By happenstance I got a fuel flow meter and
digital EFI about the same time I got the BigBore, though certainly not required they helped me see what was going on better, the HackMan Leaner was the final addition, no wait, the final addition was the Prince Prop. Or maybe it was the wing pods, it never ends

haha yea no kidding!! I'm thinking next will be some bigger rubber, and a longer prop with the added ground clearance! lol...

finished it up tonight and started it! got everything good and hot... I had already added about a degree of pitch during the install... WOT I saw 5800+ rpms!! so I added another degree!..... thats a good sign as far as power goes! going to check torque values, and hopefully fly tomorrow! so far so good though!

built an intake setup tonight too.. i think it will work good power wise, but carb icing makes me a little nervous.. it's rarely humid in these parts, and the radiator is blowing heat right onto the carbs.. but this could be a bad idea! not sure...

Got a couple hours in today on the big bore kit.

I believe I need more prop.. had to add almost 2 degrees to eat up new found RPM, but not seeing the performance increase that should go with that kind of power change. I think I have too much pitch in a sense.. just beating air around. Still playing with pitch trying to find the best spot I can on this 68" and get all I can (ground clearance will be an issue for me - so larger tires, and THEN a new, longer prop ... )

Noticed the biggest difference up high.. lets just say it will climb much higher than I should be going, with FPM to spare. On the small "speed" wing.

Starts great, runs smooth... fuel burn good. Air fuel ratio right at WOT is a little lean.. low 13's to 1 afrs... 1400-1450 on egt though so still ok. Everywhere else it didn't change much.. little leaner in cruise, still need hacman in cruise.. just wide open it got noticeably leaner. Might be an issue at lower elevation, so I may jet it just a little. We'll see.

Don't want to hijack your thread, just figured I'd post some initial results. Fuel burn looks great, used just a smidge of oil, should get better with some time to break in as yours did.

Think it will really come to life with the right propeller. Even going to a 70" warp would probably help a fair amount.

.... it never ends

It wasn't until I finally got the right Prince prop that my BB really got dialed in. Though it was still a major improvement with a re-tweaked Kiev, the Prince really made a huge difference. I'm not saying you need a Prince specifically, just that I'm not surprised you are experiencing some issues, especially as you went bigger bore then I did

I just flew to S. Dakota and back (13+ hrs @ 3.85 gph of regular mogas) and Mr. BigBore Hal was there also (and flew even further of course, coming from Elko, I think he won the "furthest flown" award if there was one). At one point we went out and were screwing around on a nearby lake doing some island landings, then on the shoreline. On short notice and without any forethought, while we were both back taxiing for takeoff, I asked Hal if he wanted to drag race. He of course was up for that, so PA-12 pilot Pete, who was already in the air, did the count down. I think Hal's plane was unloaded, I still had my 30 lb. bike on board, and I may have 10 or 15 lbs on him, plus heavier gear and tires, but I got off sooner and appeared to be holding the lead in climb, though we broke it off pretty much after we got to 200' as the intent was to see who got off first.

He has the hi-comp mod, so for sure more power then me, and while we both know our planes inside and out, I think this drag race really showed what the right prop, in my case the 78" Prince, can do. It was a win/win for me, if I would have lost I could have blamed my engine and the guy who came up with the mod, if I won, I won! Great fun, we had a blast.

Tom: how did the cargo pods fare on the trip? I saw a few pics on FB with them on your plane in SD.

courierguy wrote:It wasn't until I finally got the right Prince prop that my BB really got dialed in. Though it was still a major improvement with a re-tweaked Kiev, the Prince really made a huge difference. I'm not saying you need a Prince specifically, just that I'm not surprised you are experiencing some issues, especially as you went bigger bore then I did

I just flew to S. Dakota and back (13+ hrs @ 3.85 gph of regular mogas) and Mr. BigBore Hal was there also (and flew even further of course, coming from Elko, I think he won the "furthest flown" award if there was one). At one point we went out and were screwing around on a nearby lake doing some island landings, then on the shoreline. On short notice and without any forethought, while we were both back taxiing for takeoff, I asked Hal if he wanted to drag race. He of course was up for that, so PA-12 pilot Pete, who was already in the air, did the count down. I think Hal's plane was unloaded, I still had my 30 lb. bike on board, and I may have 10 or 15 lbs on him, plus heavier gear and tires, but I got off sooner and appeared to be holding the lead in climb, though we broke it off pretty much after we got to 200' as the intent was to see who got off first.

He has the hi-comp mod, so for sure more power then me, and while we both know our planes inside and out, I think this drag race really showed what the right prop, in my case the 78" Prince, can do. It was a win/win for me, if I would have lost I could have blamed my engine and the guy who came up with the mod, if I won, I won! Great fun, we had a blast.

Man that is awesome! Just goes to show you how much difference the right prop / right setup can make. You obviously have yours very well dialed in!

I'm doing a second oil cooler so I can be rid of oil temp issues once and for all, regardless of outside temp (in theory anyway lol) - it gets to 250 climbing and I back out... . And then I can focus on finding some ground clearance.. somewhere... and swinging a little more meat up front!

I forgot to mention earlier, but I appreciate your thread. I read this one and a few others while doing zipper homework, and seeing and learning from your propeller search makes what I'm seeing make a lot more sense.

Simko should be a salesman for all things S7...got me thinking about that Prince Prop...along with the 3 French-Canadian doxies. [emoji1]

courierguy wrote:[/URL]

Is that a 4" or a 5" cap spinner you have there?

4". And I don't recall were I got it, many have asked! It was in the parts drawer for years.