This is the story of the new top-end on N71HR, and the associated break-in and first akro flights. I look back on that experience and see an enormous learning experience - I learned quite a bit about myself, my friends, and most importantly about engine operations in the airplane.
PART I - Trouble
On 16-May-1998, I flew over to Korey's for what I thought was going to be a routine maintenance check, with maybe some spark plug work, and a couple of other miscellaneous engine checks. I was expecting to land at Westover around lunchtime like I always do, get a bite to eat with Korey, turn some wrenches, and make it home for dinner. Boy, was I in for a big surprise.
The first indication that something was wrong actually came weeks earlier. Sporadically, the airplane would fail run-ups and in general run a little strange (hope these terms aren't too technical). It acted like badly fouled plugs, as the problem would always "go away" when it was run-up and leaned out. The engine was acting like it was too rich, which caused us to pay much more attention to leaning (which ended up causing more problems, another story altogether). I thought perhaps one or more of the plugs were cracked, or badly out of gap, or something relatively simple along those lines. Wrong!
About halfway through my Freestyle at the Gold Cup Regional Contest in Victorville, CA, while motoring across the box, the engine spooled down about 300 RPM, sat there for a second, then spooled back up. All through the contest, which was the early part of May 1998, I felt the airplane was not developing full power, but I dismissed it as a symptom of the high density altitude of George Air Force Base (field elevation is 2878 feet!) where the contest was being held. The RPM drop did not repeat itself the rest of the weekend, but the nagging thought was planted in the back of my mind that all was not right with the engine. I continued the contest, and even ended up winning Advanced. During the entire 3 hour flight home, I couldn't stop thinking about what the problem could be (I get bored fairly quick on cross-countries). The following Saturday (16-May), Curt went for a morning flight, and when he got back, he reported that there was no way that engine was putting out full power. Time to head to Korey's.
We pulled the plugs, and they didn't look all that bad. Next came a compression check, and all cylinders were acceptable except number 3, which was pretty low. Uh-oh. Here we go. More checking, poking, and prodding, and Korey determines we are getting blow-by on the valves (he figured this out by sticking his ear up to the exhaust pipe). He thought maybe a piece of carbon or something was lodged in between the valve and the valve seat, and that he could jog it loose manually. If not, he would have to remove and disassemble the cylinder to clean out the valve seats. Crap. Now I need a ride home, because I sure can't fly the Pitts like that. 4 weeks before Paso, no problem.
Turns out Korey got one of those funny feelings, and decided to check the rest of the cylinders. He discovered blow-by on ALL the cylinders. Whoops. Off come the cylinders. We decided to send them out to Lycon (the aerobatic engine specialists in Visalia, CA. They do most of the Reno race engines, plus the big names like Sean Tucker and Jim Leroy) for inspection and repair. A couple of days later, they call Korey and inform him that basically the cylinders are TOAST. Stepping on the cylinder walls, cracks between the valve ports, and a few other goodies that I can't (or don't care to) remember. Now it's decision time. The cylinders need replacing, in fact, the entire top end needs replacing. We have a couple of options on what to do, so we start thinking about it. We had talked all along about pumping the engine at the next major. Now, here was an opportunity to do a little pumping, and simply move some of the events forward in time. Well, while we're at it (isn't that always how it starts off?), we may as well add a fuel injection system, since we planned to do that anyway, and plus the bigger cylinders and higher compression may be too much for that trusty little Bendix pressure carb. OK, decision made. 10.5/1 compression pistons, ported and polished cylinders, and a flowed Bendix fuel injection system - the works. Problem: Paso is now THREE weeks away. This is going to be tight. Korey basically clears his schedule (I'm still buying him beers for it...) to pull this off. We place the order with Lycon. They are pretty notorious for being late with this kind of stuff, and we decide that they are the main stumbling block to meeting the time frame. Everybody I talk to says "Oh, you probably won't make Paso..." and blah, blah, blah. To hell with the "nay-sayers". We can do it. We made a plan to do all the work and fly off the test flights and 15 hour break-in in 2 weeks (with no intention of compromising on ANYTHING in the least - we all agreed that we would do this right). The original plan was to have everything done by Saturday, 6-June, take the plane home, and begin flying off the time. That would give us roughly 4 days to get everything done before I had to leave for Paso on Wednesday 10-June. It IS gonna be close!
PART II - Put on your rollerskates
Korey stays after Lycon to meet their promised timeline. I call Korey everyday (sometimes twice a day) the entire three weeks. It's getting to where he knows it's me calling just by how the phone rings! On schedule, Korey flies down to Visalia on Thursday 28-May to pick up the cylinders. Lycon came through! Now the pressure is on Korey (don't worry, he wouldn't even dream of compromising any aspect of quality or safety). I am nervous, and Korey is working 15 and 16 hour days. Man, I'm gonna owe this guy my first born...Saturday 6-June is looming ever near. Korey stays on schedule right up to the day we were going to bring it home. He was planning to do the initial test flights on Saturday morning, we show up Saturday afternoon, fly some, and head home. But, there was too much work, so it's not finished. Curt and I go out on Sunday 7-June to work all day, the three of us, on getting it done. Finally after lunch we are ready to crank up for the first time. She fires on the fourth blade. I am so elated I let out a whoop that Korey heard over the engine noise (he of course continues to play it cool, but I know he was also happy). High five to Curt. The engine sounds very different - meaner, with more of a "snarl" to it. It definitely has a deeper, more throaty sound. I am liking it. But, after a few minutes running, there is a slight problem. The mixture is too lean. Whoo, boy. This is going to be a rollercoaster ride - highs and lows, highs and lows. Paso is now 3 days away, and I feel it slipping away. At this point, the contest is more of a distant thought, and the focus becomes getting the engine dialed in. If we make it, great, if not, well...Bullsh*t. We're going to make it.
We don't take the plane home on Sunday, because it wasn't ready to fly until late in the afternoon, and the weather was NOT cooperating - 200 ft overcast ceilings are not very conducive to new engine test flights. Crap. Curt decides to take Monday off to go back to Korey's and hopefully bring our beloved airplane home after some break-in time. I decided to take Tuesday off (I already had Wednesday scheduled off for contest setup), but I can't wait so I go out to the airport Monday evening after work to try and burn off an hour or so before sunset. There is LOTS of work to be done during these test flights - figuring out where the fuel mixture is, recording EGTs and CHTs on a kneeboard for hours on end, etc. My first impression after I takeoff is what a ridiculous deck angle is required to maintain 110 mph on climbout. I feel like I am on a 45 degree upline, just like in practice for competition. I can tell I'm going to like this.
I'm up at the crack of dawn on Tuesday 9-June. I have the whole day planned out, where I'm going to go, work in a stop-over at Korey's about mid-day for some check-ups, everything looks great. Out to the run-up area, do a run-up, and something is very wrong. It's running like crap when I turn off the left mag. NO!! This can't be. I do another run-up, lean out, it seems to get a little better. OK, I'll go. Out onto the runway, roll in the power, sputter, sputter. RPMs go up, come down, up, down...I'm not accelerating very fast. In fact, I'm barely accelerating at all. I am up on the mains rolling, and decide to abort the takeoff. Back on the stick, oops, get a little airborne there for a second, OK, back on the runway and rollout. I turn off, taxi back to the runup area, and the same thing happens - it runs really bad on the left mag. I shut down, whip out the cell phone, and call Korey right there from the ramp (this T6 starts doing his runup right next to me - the NERVE of that guy. Can't he see I'm on the phone?). Korey puts me though some checks, and we see that we have a very cold cylinder. I taxi back to the hanger, disassemble the injector nozzle on the cold cylinder, and sure enough, something is blocking the opening. Clear that out, re-assemble the nozzle, and get ready to go. I have no time to waste! I fire up, check the temps, and everything seems OK now. Whew! That was a relief. Only while I'm taxing out, I hear this light pop. "Wonder what that was" I ask myself. Hmm, everything seems OK. Wait! The tachometer is dead. Crap. Shut down, cell phone out, call Korey. He has me check all around the tach cable housing, nothing is dangling there, so we determine it's just a broken cable. OK - I now need to go directly to Korey's, but with no tach. I just listen very closely to the engine and keep the cruise speed to 140, which should equate to about 2500 rpm. Weird. I still look at the tach out of habit, but of course its not moving.
I land at Westover. After taking things apart, we confirm that the tach cable is broken. Just an incidental thing, could have happened anytime. NO! It picks now. Fine, let's fix it. We replace the tip on the replacement cable we bought, because it didn't have the right tip. OK - back in business. I have now lost almost a half day. I takeoff to go to Visalia to pickup some injector nozzles, as we have determined that cylinders 1 and 2 are not getting enough gas. I change the nozzles right there on the ramp at Visalia and head home. I'm supposed to leave for Paso tomorrow, and we're nowhere near close to the end of the break-in time. I make a strategic decision to skip setup at Paso in favor of flying off more time, and hopefully finishing. Gonna be close. I decide to pack up for Paso, fly around all day Wednesday, at end up at Paso end of day Wednesday.
Up early again Wednesday morning. It's going to be a LONG day. Load up, push out of the hanger, fire up and go. Everything seems fine. Get to the end of the hanger row, and the tach dies again. This is getting slightly old. I shut down and call Korey. He decides we need to replace the entire cable, so he finds a shop that can do it and I fly there. Clarksburg, CA, just south of Sacramento. The 2200 foot grass strip is a little challenging to land on (never landed on grass before), but I pull it off. They disassemble the cable, and discover the tip is rotating on the inner cable, and so they just replace the tip. Great, only lost an hour there. I thank them and blast off.
I take of and head north. I need to get at least an hour on before stopping in to Westover for more checks. The weather stinks, with a 5000 ft overcast and spotty rain. I fly through some rain here and there, but it's no big deal. Finally get to Korey's, we do some checking, eat lunch, and I'm off again. Now I just have to stay in the air for several hours, and record all this data. In case you have never sat in a Pitts S1 for hours at a time, it's not very comfortable. I am driven, though, because I have a mission, and nothing is going to get in my way (well, almost nothing - I do need to stop for gas).
Wednesday saw 5.3 hours total flight time, which basically took a full 12 hour day. I was extremely tired, sore, deaf, and generally no fun to be around, but I landed at Paso Robles at 8:15 PM. Naturally, everyone was gone. I checked into my hotel and started calling people. Korey first - I read off all the numbers I had gathered, and he thinks everything sounds good. The definitive factor would be the oil level in the morning. If the oil level continues to go down, that means the piston rings haven't seated and akro may not be very good for it yet. We had amassed 13.5 hours in those three days, and the contest was upon us. Korey was flying the contest, so he expected to arrive Paso the next day (Thursday), and we could do some final checks and maybe do some akro. It was then it hit me - my first akro flight in three weeks could potentially be in the box at Paso, the day before the contest! Whoo, boy - this is bound to be ugly.
Korey arrives the next day on schedule. Turns out the oil is a little low, so we call Lycon to talk it over with them. They say "go for it", so we change the oil and I'm off. That first pull to vertical was such a wonderful feeling, I completely forgot about how bad my butt hurt, forgot about the tribulations of the previous 10 days, and I just enjoyed flying the airplane. Wow, power is NICE. We have a whole new personality here! I go back to the airport, and since the box is clear and the weather is lifting, I am cleared for a sequence in the box. Feels a little rusty, which I was expecting. Oh, well. At least we made it! I can feel the differences in the airplane - it snaps different, rolls a little different, and the pivot at the top of hammerheads is a little different. Will definitely take some getting used to, but I love it. Yehaa!
This story has an even happier ending. I took second place in Advanced, out of 11 pilots. Needless to say, I was on cloud nine. Actually, with all that power, I had climbed up to cloud fourteen or fifteen!
Thanks Korey.
Last update: Wed 24 Jun 1998 17:30 PDT
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