Pretty impressive. Should swap from grass to asphalt and really be impressed. I quess the weight was about the same.

15 hours now and I am liking the performance still, no issues, plus buying REGULAR mo gas!

I am heading back down to Elko in a few days, depending on Hal and my schedules, driving this time and delivering a 3 KW solar array to him. Separate from my engine deal, I paid retail for that. This time I'll be the one who knows what he's doing, and he can be the one who watches!That is going to be one long drive, after that direct flight, with tailwinds both ways.

I take it that is your Bearhawk, Blackrock, in the hangar I was in?? Wow, when I got bored watching Hal I checked it out, very nice, those control surfaces are huge, and I like the simple light panel you used. Quite the flying machine.

180marty,

I'm not entirely sure on the weights.. I do know that Hal was full when we left Elko so was maybe down 9 gallons or so but he also has larger tanks. both planes were flown solo. The turbo weighs 25 lbs and I'm sure, Mark, the turbo'd pilot weighs more than Hal, too.

CG, thanks for the kind words on the BH. I'll be back in Elko Friday so if you are here that late in the week, I'd like to learn more about your solar offerings.

Blackrock

You have to consider the DA. Hal would have really out performed at lower altitudes, would have loved to have the 1622 up there to compare although a different plane and weight, I know I am heavier than Hal

I have my new mixture control installed, but have yet to use it until my EIS/EGT gauge arrives. It should be here Friday or Saturday I think I have the proper measurement for the EGT probe location: 2 3/4" from the exhaust flange, but don't know if that's from the outside of the flange fitting, or up against the outside of the head (3/8" difference) or if it doesn't matter, close enough in other words. As of now I'll go with that measurement from the out of the flange. A bit over 15 hrs now on the conversion.

When I get it installed I plan to fly around and see what temps I currently am running, my current fuel burn, and then ( ) start playing around with the mixture control while keeping a close eye on the EGT's and the new fuel flow indicator, this will be something entertaining to do on a high alt. (8K +) long flight, where I understand the HACman mixture control does best. About all I know so far is 1560 degrees is considered max EGT on the Rotax? I can't wait to see what I'm running now, and then to play around with it a bit leaner, but not too lean.....any advice or parameters, Big John, you want to throw out there would be appreciated. On top of these changes, I have a new Prince 78" prop arriving in less then 2 weeks, and I am trying to makes these major changes incremental, to get a better handle on what works and what doesn't. The ZIPPER works for sure.

Thread drift: I've also been shedding some panel weight, it recently came to my attention that I do not need a whiskey compass for VFR day experimental flying (true, look it up). I have been hauling around different Airpath panel mount compasses for 30 years, and I took mine out today. Right a 1/2 lb! Gone!! I have not looked at it, once, in decades, I have a GPS, and paper maps, and if that doesn't work I have 29" tires and a very low stall speed, plus a on board monocular to read road signs. A more direct re-routing of my battery positive cable and also the ground from my new EarthX lost another 1/2 lb. last night. When the GRT MINI gets here, all the steam gauges come out. Next is the 3 lb. (not counting the install tray and misc. hardware) VAL 760 com radio. I've had several, with always excellent audio, but it is getting replaced with a MGL V6 at 1/2 lb. The panel intercom is also history, as the MGL has one built in, another few oz's saved. More power and less weight will work every time

CG,

If you haven't already seen them, here's a link to Mike Busch's webinars. #4, 24, and 27 might be helpful for you.

https://www.savvymx.com/index.php/webinar

Since I'll soon be flying a 912S on floats, I'll be watching this thread closely.

Except for mixture control, too close to sea level for that stuff.

-Franck

Thanks CamTom12, I'll check it out. I assume the principle (how and when to lean) is the same, for Rotax, Lycoming, or any other internal combustion engine.

FF: Exactly, the stock carbs do fine until much higher, and even then they do plenty good enough, not like there is a problem leaving it stock. BUT, if I can knock off even a half gph on the long high flights, it'll be worth it. I'm trying to keep my expectations down. I have an 8 hour duration, so say cruising before refueling for 6 or 7 hours (with stops to drain the sump) that will leave me an extra 3 1/2 gallons or so in the tanks About another hour duration.

Now that I am through with the running it hard break in hours (first 10) today I ran it more normal for me, below 5 K rpm with some 4200 to 4400, and again, the added torque is noticeable when pulling back, and the rpms don't drop!

Just opened up the 1622 to check out things inside at 40hrs, found nothing at all a small amt of lead bromine on piston which was a thin powder coating, I use Declin in the fuel for the lead and it seems to be working. Preparing for a long trip from S. Ca up through Oregon, Wa, Id, Mt and really wanted to get a good look at the inside with this new engine prior to that kind of a trip I will have one of the Grandsons with me part of the time and wanted more peace of mind. Glad to report no issues and nothing to report, That is a good thing. Looking forward to some back country time be heading out June 25 for a couple weeks.

To add what Tom has said on the Hackman, I have over 300hrs flying with one and average between 20-25% savings in fuel consumption when in cruise even at altitudes of as low as 3500' but it loves it most above 6500.

Just passed 20 hours now since the Big Bore conversion. I now have the Hackman leaner installed also. On a flight to Afton this morning at 9K with an old ultralight flying buddy from out of town I was playing around with it. Though my EIS fuel flow indicator is still in the calibration phase, it was obvious that leaning is a great way to reduce the fuel burn Also a way to increase the EGT temps, I have some richer/larger jets on the way, as now I can have the best of both worlds: a rich mixture when desired for cooling while still being able to lean her out once way up and cruising. I am without CHT probes for my new EIS right now, and had pulled the steam gauge CHT, plus all the other round engine gauges the day before as part of my current weight saving mania) though they should arrive tomorrow, so I didn't mess with the mixture and the EGT temps too much, mostly just a test run, and breakfast of course. The next few hours should see the jetting optimized for the new larger displacement Big Bore Rotax/Hackman leaner/GRT EIS combo , in the meantime I'm flying about every day. Right about the time the dust settles on all these changes, my 78" Prince Prop will arrive, to stir things up some more.

Now that I have (for the first time) a digital representation of my EGT temps, I found that my Swiss Muffler seems to accidentally be acting as a tuned exhaust of sorts. Removing it anyway resulted in a immediate reduction of EGT's by 35 to 40 degrees. Having had it for 1300 hours, I have decided I have "been there, done that, scratched that itch, etc." and at 7 lbs including the mounting hardware, it is now regulated to the "good idea, fun while it lasted, but let's move on" wall. A little nosier, sure, but still damn quiet, I'm good at finding solutions to non existent problems. Plus, being on a weight reduction kick, losing 7 lbs for NO money is irresistible!

As expected, driving to Elko after flying there a few days before really sucked, especially hauling a wide and somewhat fragile load, this 10' wide by 20 long solar array. A good picture of Mr. Big Bore, Hal, right after we first took his 3 KW solar grid tie system for a test run

20 hours already. Do you live in that thing?

Not in it but very near.... 40' out the front door to the hangar! More then 20 hrs. , I deducted the 1.7 hr. recent deadstick flight, figuring that had nothing to do with the Big Bore conversion, other then taking 3 lbs off the weight that is?

That reminds me, after talking with Lonnie Prince about my new 78" 2 blade prop, the last thing I asked him was did he think it would be less drag deadstick then my current 70" dia. 3 blade KIEV, he seemed to think it would be less overall, cool.

Not in it but very near to it... about 40' out the front door to the hangar! More then 20 hrs. , I deducted the 1.7 hr. recent deadstick flight, figuring that had nothing to do with the Big Bore conversion, other then taking 3 lbs off the weight that is?

That reminds me, after talking with Lonnie Prince about my new 78" 2 blade prop, the last thing I asked him was did he think it would be less drag deadstick then my current 70" dia. 3 blade KIEV, he seemed to think it would be less overall, cool.

Still no Prop tests due to the Sensenich prop provided uses smaller Hub mints, So this is delayed until I get back from the NW Trip. We did have the Exhaust modified to open up and breath better and added a second exit exhaust pipe, Truly made a difference allowing better acceleration and added an additional 80 Rpm on climb out, Required the needle clips to be moved down to the 4th notch lifting the needle, This helped on EGT temps once pulling back to cruise. New Exhaust really Sounds good, Much deeper sound.

I was playing around with the Hackman mixture control today, finally got up nice and high, and for a couple hours. 11K + and I was truing out at 102 mph and later confirmed the still calibrating new fuel flow indicator that I burned 3.9 GPH in 4.5 hrs. Getting up that high was effortless. I was easily able to knock off .6 of a gallon fuel flow while the temps stayed good. Still not real sure how to use it....... by that I mean it is very tempting to go leaner and leaner and keep watching the fuel flow dropping (like .7 and .8 gallon less, while ignoring the rising EGT temps). Today I was at 1425 degrees, about 75 or so less then max. Max for those conditions that is, the stated max for the Rotax is 1560.

I changed the stock main jets to 158 (from 155) and my CHT's are the coolest they have ever been, 160 was the highest I saw all day, oil about 180, just right. Egt's 12 to 1300 in cruise, 950 at idle. Starts as easy as ever. When topping off at Picabo, where you can pull right up to the pumps, I saved enough by buying regular instead of premium (all I need now at this altitude) to pay for the coffee and doughnut I got to go! Yeah, I'm that frugal...... With the other weight saving changes I've been making, I can really feel the difference IMMEDIATELY on take off. The throttle response is right now, less piston weight is why, I'm told. A couple of times on some off airport takeoffs, I found myself slightly behind the airplane, surprised that I was no longer rolling but well airborne and strongly climbing, it's that more power and less weight thing, put the two together and damn!

Anyone familiar with Smiley Creek knows that when southbound, you have a hell of a climb and right away. With the cool weather today plus the Big Bore changes (and the weight losses the plane has undergone) I simply waltzed right over Galena, really kicked it's butt, didn't use full throttle even, and again with little effort or sense of working the engine hard, as the low temps confirmed.

I'm enjoying reading about this. Obviously the power gains are awesome, but the CHT temps are what is most interesting to me. I am already biting my nails every time the ambient temp so over 70 deg. I have gotten the engine a little to warm once already and she puked coolant all over (but quickly got it under control). Temps are becoming nerve racking as we get hotter every day here (plus high humidity).

I am already envisioning chopping up the cowling and scooping up more air somehow. 120 C is not uncommon to see if not careful. That's too hot.

I have been following this thread with great interest. My S-7 has had excessive oil useage since I bought it. Granted the plane sat for 11+ years unflown which might have something to do with it. It is an 80HP with the Extra-Performance 95HP pistons installed. I will have to take off the cylinders to check the rings anyway so have decided since I am tearing it apart I may as well try for a little 'extra' HP since as we all know, one can never have too much power. I will eventually be putting the Full Lotus amphib floats that are sitting in my hangar, on this plane also. Floatplanes love HP!!

I spoke with Jay Stewart last night and he is sending me the dyno print outs and ordering info. Hopefully I will order a set this week and then the fact will hit me that I have to tear the engine apart and install the new cylinder/pistons. Wish I would have had them now since it has been raining for several days and I could have been working in the hangar.

I am not 100% convinced I have a legitmate use for the Hackman leaning kit but may eventually get that also. Most of my flying is within a couple hundred miles of my home strip in northern MN so higher altitudes are not commonplace. My usual flight altitudes are under 3500' MSL.

I appreciate all the posts from Tom and Big John on helping me spend more money.

I am also very interested in conversions to get more power. Does anyone know how the Joel Milless turbo conversion project is going?

BTV wrote:I am also very interested in conversions to get more power. Does anyone know how the Joel Milless turbo conversion project is going?

First I've heard about it.

Living at 5400' with high terrain all around, a turbo makes sense for me, and I had given it some thought in the past. But, I didn't like the added weight and complexity. Losing weight with no added complexity, yeah, that's the ticket! I forgot to mention, yesterday at 11K +, it was still climbing with gusto, around 500 fpm. All in all I'd have to say the added horsepower claims are conservative or at the very least accurate.

Swingle did the video. It is in the Ohio Bush Planes video section. I'd put a link but don't know how.