After hearing about prop. control problems and excess heat in engine after a 10 minute flight with baffling not quite correct and succession of hot ground operations I spent 1/2 of a day trying to reproduce the problem, talking to continental and a prop shop about failure modes. Conclutions, or possible scenarioes. 1) It is possible to overheat my IO-520 on the ground if you run it long enough. This is a design limitation same as some Mooneys have, if I had the cowling of a Bonanza (2x the airspace) it wouldn't happen. 2) If the baffling isn't set correctly on cowl closing (it was still being trained) it is possible to get the engine quite hot in one 10 minute flight and this can heat soak my engine for 10's of minutes after shutdown. 3) The oil temperature of a heat soaked engine can show up suddenly on a following start, oil temperature readings can lag quite a bit. 4) Continental and 3 mechanics agree there is not enough energy being generated in a IO-520 engine to push it to redline on the ground at 1700 (or lower) rpm, at least not in a few seconds. This combined with the normal shutdown of the engine (as opposed to a grinding halt) means the heat had to be mostly present prior to start. 5) It is possible for prop control to partially fail, if the oil is frothy with air, or thin due to high heat. This is verified by one prop shop and one mechanic. The fact that this only happens when the oil is REALLY hot is suggestive. Solution don't let the oil get REALLY hot. The general consensus is if this was a part trying to fail, you would either get a failure or not. It wouldn't be an intermittent thing.
I talked to 3 different mechanics in addition to Continental and a prop shop. All 5 sources agreed the engine and prop were in reasonable shape especially when repeated attempts to fry the engine and yank the prop control out of the socket were futile. Nevertheless I made 2 mechanics go over the prop control from front to back again just in case. No problems were found.
After agonizing over the whatifs, and seeing that flights with the baffling in position could only heat soak the engine enough to cause 160 degree oil on later ground runs after 15-20 minutes of moderate power while yanking out the prop control. And after hearing mechanic after mechanic say they would go to Oshkosh with me in my plane without qualms I decided to go with the following stipulations.1) ANY oil temp on the ground over 212 (A number a Bonanza guy gave me)F would be grounds for grounding REGARDLESS OF TEMP OR DENS. ALT. 2) Failure of the prop control more than a few times would be cause for further investigation. 3) Cruise CHT over 410 (Continental quoted me temps of 390-410 as good) would be cause for concern. 4) Climb temps. over 430-435 would be cause for concern. 5) Oil temps in flight over 215 would be cause for concern especially if not linked to highpower hot operations. 6) I would now have a mechanic with me on my trip to diagnose any problems that might occour. 7) Prop control failures would be full pitch, and since this is landing configuration wouldn't be a safety issue. 8) Engine failures would be bad, but said mechanic would be queried on engine health for EVERY takeoff while rolling and in climb. I made this quite clear that any abnormality would be cause for abort.
Mechanics would continued to look for problems through Tuesday. I stayed home trying to recover from an upset stomach due to chasing problems and trying to reconcile apparently contradictory data, but I am now satisfied that the problems will not occour if I ensure the baffling is arranged properly to avoid getting the engine too hot in flight, and causing later problems on subsequent starts when the engine is still fried from not enough cooling. And even if this isn't the scenario I can spot the problem on the ground (since that is the only place this has shown itself)
4:00am Having previously done W&B and fueling we loaded the Navion up, did a very thorough preflight and runnup, continuing to abuse the prop control trying to force a failure and running the engine on the ground no luck Oil temp was 160, prop control did not fail.
6:00am (PDT) Takeoff, full power available on short runway from PAE, (long runway still closed) Nothing out of the ordinary. We called flight service and opened our flight plan. CHT in climb were 400 or lower the cowling is working. Oil Temps remain at or below 200 in climb.
Leveled off at 11500' closed cowl flaps 67% power 198-201 on the oil temp, 390 on the CHTs. Engine ran fine, did lots of power/fuel flow checks, and speed checks we were truing at 150kts and on target for a 4 hour flight to Billings. I went on Oxygen my stomach was still sore and I felt much better on O2.
Enroute I started to file my first pilot report, but the Com/Nav #1 circuit breaker popped out after about 3 minutes of broadcasting Joe (the mechanic) switched me over to com #2 and I continued to talk. We reset com 1 and noted this problem for future reference, Com 1 continued to work for flight following and other normal uses. We followed V-2 mainly for the terrain clearance and since it puts us over highways/freeways and a number of airports going through the cascades and the rockies.
9:50am-10:00am (PDT) Cleared for the straight in at Billings, just as I was trying to slow the Navion down from a steep descent, Billings tower wanted me to keep my speed up on final, due to someone shooting an approach, I said I could until I popped the gear, then I'd have to be and stay at 87kts. He told me to drop my gear at the last minute, and then started to ask me all kinds of questions about my nice plane :-). My response was "Do you know how hard it is to slow these things down?!, and thanks" and prepared for a go around. After clearing 500'agl below me for towers etc. I dove below GS (don't tell) down to about 500'agl, pulled up not too quickly into a steep climb with power way back, looked for 100mph, dropped the gear, arched over in a 0 (or low gee) arc, and ended up on GS at 89mph with a small amount of flaps for the big runway. "Wheeee" I think this was the best landing of the trip.
We refueled and went in search of lunch and the Flight Service Station that USED to be in the main terminal building (It was closed) While I ate I did my flight planning for the next leg, to Alexandria, Minn. Home of the Bellanca plant.
On return to Lynch we talked to a pilot in a RV-6? from Spokane, and a guy visiting from Calgary in a 172. The Navion is drawing lots of people ooohing and aaaahing over it. I called the weather and filed my flight plan for Alexandria there were supposed to be widely scattered thunderstorms, but to the south of our route, and we had an out to the north if we needed it.
noon (PDT) It was 95 degrees at Billings when we started the engine, had to do a hot start, but just hitting the boost while the engine was catching for about 2 seconds did the trick. The oil temp quickly rose to 165 degrees a few minutes after startup, the engine was STILL lukewarm from last leg. Did a full runup, yanking the prop control again, no problems. We were waiting on the ground for about 15 minutes. In that time the oil temp went up to 189. As soon as I went full throttle for takeoff the oil temp and CHTs dropped a testimony to the cooling power of all that fuel and air. During climb I saw oil temps of 205 and CHTs of 410, but I lowered these by climbing at 115 instead of 110 indicated MPH. Climb rate was very good (at least for a Navion). It looks like those flap seals do help.
Back up at 11500' I went back on O2, we were well fed awake and happy I think I drank a little too much coffee but bladder range was still ok. The sky was clear for the most part, and we never had to deviate. Since we were clear of the rockies and everywhere looked like a nice big flap emergency airstrip, we started going direct to airports. Joe and I were pretty much in synch now. I was tuning and identifying radials on VOR #1 #2, tuning my ADF to stations for extra info and lightning listening, and Joe was triangulating and verifying visually our position. The GPS was helpful, but I really wanted to make sure we knew where we were relative to local features in case of emergency. It was good to have a pilot you could turn over the controls while you drank water, calculated HP/FC/ETAs talked to FSS etc. etc. We were on flight following but someone had a xmitter that kept blanking out ATC every second or so. Pretty annoying, eventually we were far enough away from the disturbance that it didn't bother us anymore.
3:50-4:10pm (PDT) Started our descent down to Alexandria. I was screaming (for a navion) midway in the yellow arc, and the engine was a comfy warm 350 CHT. 187 Oil leveled off on the extende 45, lost enough speed, dropped the gear/flaps and landed without incident at Alexandria. I was REALLY burned out after 8.5 hours of flight, although having another pilot really helped. We refuled and deplaned for the night. We wanted to visit the Bellanca plant but they were closed by the time we got there.
BOY we brought a lot of stuff, ice cooler, tentS, sleeping bags clothes, munchies, tools galore, more munchies, my 40lb flight bag from hell, backup GPS, backup handheld/vor, backup headsets, this was like a major road trip in a cadillac with the back seat brimming with necessities and luxuries. I made Joe do the driving of the courtesy car, since I had no more brain left. I got lots of sleep that night after dinner at Bonanza's
5:30am(LCL) Woke up and headed for the airport 5:45-7:00(LCL) Did weather and intensive preflight. Looks like we are burning a quart of oil every 4.5 hours, not too bad for a IO-520 running at 67% power on a hot day, but Joe noticed more oil being burned on the left side (probably from Cyl #3 (the hottest by a little bit). We noted that this oil was within the limits set by continental. I noticed a tiny bit of Hydralic fluid had dripped from the overfill tube and panicked until I remember George had told me he filled the hydraulic tank a little full and to expect this. The fluid level was still above full, so no problem there.
For you math types, on page 1-3 of the IO-520 Series FAA APPROVED Continental Aircraft Engine Operator's Manual there is an equation Oil consumption (lb/BHP/hr,maximum at rated power and RPM) =.006*%Power/100 at 67% this works out to .00402 lb/BHP/hr BHP at 67% is 191 so oil burn should be a maximum of .00402lb/BHP/hr*191BHP=.767619lb/hr 4qt/gal*(.77lb/hr)/(7.5lb/gal)=.41qt/hr or a quart every 2.5 hours. Since we are a good margin over this no worries.
Took off, after a normal runup no problems, we are on our way to Oshkosh climbed to 11500, don't need O2 this time. It is really hazy out, visibility is quoted at 12mi, but we don't believe it. We head to Eau Claire visibility sucks but still VFR. Can't get through to FSS too much traffic, I started talking to a Navion (91424) coming up from South Dakota on 122.75 about 100 miles away from us, got some atis info for someone else who was still too far away to recieve the atis for their destination. Traded pilot reports with pilots (since FSS was not any help at all) We also tried to get flight following at Minneapolis, no luck, no suprise the area was BUSY BUSY BUSY. We kept our eyes peeled.
We did the last 38 NM of the trip at 1800MSL with the gear down, the
lights on, ... ALL the lights on, at 85kts. We headed to a small airport
and were proceeding VFR towards some lakes via mag. compass/DG (I had
previously reset the DG because after 2 hours it had apparently precessed
30 deg.) for about 9 miles we convinced each other the terrain outside
was what was on the map, but then it became obvious something was wrong.
we headed back to the last known good point (that small airport) and I
noticed the heading back to the airport was no where near the apparent
30 degree crab our compass was telling us we had (we weren't crabbing
at all if you looked at the ground) It then struck me again that the
DG had apparently precessed 30 deg. I started suspecting the compass it
did have a big airbubble in it, that I had not noticed earlier or at least
it used to be tiny. On a hunch I bent the glareshield (and the compass) back
up to more or less straight and level (remember we were flying with the
gear down at a higher AOA at 85kts.) Sure enough the compass swung into
the approximate correct position (as verified by the two GPS's we now
had running to verify track) Mystery solved we made sure to take compass
readings with the glareshield twisted to level. And supplimented track
with GPS info, we were not in a good position for VOR/ADF info, this low
and at this position. We were back to being happy we had all the
visual cues we needed, headed to Rippon, and saw a bunch of FAST warbirds
whizzing over our heads at 2300' MSL Oshkosh was closed to general
aviation traffic, but since we were in a 1951 plane we were at least
guaranteed Classic parking :-) We were getting close in to the airport
still no one was talking to us, we did hear another 'silver navoin' being
vectored behind a B-26 more on this guy later. Eventually I picked up a
highwing that the tower was talking to and called tower "Navion 5375K
(position) you aren't talking to us yet" tower came back with "Navion following
the highwing rock your wings
After I turned off the runway, instead of being led to Classic parking the ground controller (on a moped) was leading me to the west, I had no idea what was going on, until they passed us off to a jeep in the warbird area, Joe suddenly bursts out "They think we are a warbird" :-) :-) We parked next to another silver navion in L-17 colors in the warbird area I was busy shutting down everything, closing my flight plan and powering down. Joe was busy getting congradulated by a ground controller for making it in. Turns out we had a ride in the warbird jeep to the warbird camping area and had our multitude of stuff hauled in the same jeep. We had complimentary mug, hat, and two free week long passes, just for being a warbird. Life is good.
We finally made it after just under 11 hours of flight time.
We talked to the Navion owner of the silver Navion (L-17) next to us he said he was on an IFR flight plan to OSH and we passed him over EAU like he was standing still. He got in first, because on the IFR flight plan he didn't have to go out to Rippon, and he didn't have to get lost for a couple minutes while he figured out his compass was whacked at high AOA. As it was he was only a couple minutes ahead of us. But he did ok for a E-225 powered Navion.
Joe and I wandered around until noon, I was looking at Navions mostly, Joe was looking at Swifts (naturally) We met up at the tower at noon, where we met Bud, a Navioneer from Anoka Co. Minn, Bud and I have been in contact over the last few years, since he is putting together a Navion, he just got it legal Tues before Oshkosh, but didn't have time to get current enough to fly it into Oshkosh, so he flew his Cherokee in the previous day.
Thurs night Bud and some friends took us out to another Bonanza-like-all-you-can-eat place. Afterward we slept like the dead.
We woke up early every day (5:30-6am lcl), showered/fed and started looking at planes.
The BD-10 did aerobatics, pretty impressive. The Concord showed up late Saturday, and was giving rides (for a lot of money) Sunday they had to postpone a trip due to "mechanical problems"
My tent had dark green chord for tiedowns, and everyone kept tripping over it I'd wake up with a pole in my face. I eventually grabbed my good old duct tape, and made little silver flags to keep the ties visible, it helped a little.
Saturday night/Sunday morning I started stopping by the FSS on the field and getting weather for a potential Monday morning t.o. It looked a little iffy, but not too bad. Sunday night we had some nice thunderstorms, my tent was getting blown around so much I couldn't sleep so I just watched the storm until it got over.
I woke up around 3am, with 1/2 the tent in water, I scrunched up in the other 1/2 still wet and managed another 2 hours of sleep.
I woke up monday morning pounded down the coffee, scarfed down breakfast got a briefing and we were off the ground by 8am. The weather was quoted as 5mi vis. 15B and better to the south. We were cleared to rwy 27 at the rwy 4 intersection. I was told to position and hold, then told to turn immediately to the right, then the tower changed their minds and cleared me for an IMMEDIATE TAKEOFF, BOY it was hard getting out. We stayed at 500' as requested for departures and immediately tossed our plan to climb since the weather was too low. We cruised for 45 min. to the south where the weather was getting slowly better. Eventually we found a 'hole' and spiraled up. We only saw one other highwing on our low level portion under the cloud deck, but saw him in plenty of time to avoid. I don't know if he ever saw us, we climbed to 10500' and cruised direct to Alexandria. I did my usual descent to a extended 45 entry. There was a small grumman with a student pilot who thought he might get in our way in the pattern and volunteered to do a 360 and let us in. I assured him, I'd be slower than he was by the time I turned downwind. After landing we refueled, and went over to the Bellanca plant for a self-guided tour. This place was neat. There were these old time craftsmen, doing their own wood/metal/fabric/painting work. Bellanca is building a few new aircraft a year, refurbishing a few planes and doing some goverment contracts. Joe talked to several of the older guys who had been there forever. It seemed like a nice laidback place that was surviving in spite of the scale of their operation, or maybe because of it.
Joe and I decided (based on our performance) that we were far too burned out to fly any more today, so we took the courtesy car into town and got a nice hotel room. I had several naps and watched the weather channel in between.
We woke up at 6am and after a briefing and a thorough preflight we were on our way to Billings again. Had to dodge some gliders, and some virga. There were gliders EVERYWHERE Joe and I were constantly finding traffic and maneuvering. No one at FSS pointed this out to us. At one point I had descended to 6500' over I-90 and because of the pressure altitude was able to develop in excess of 75% power at a density altitude of 9000'+ we had a groundspeed of 173kts, but unfortunately I don't know what the winds were. from the nearly direct straight in we got, I suspect they were headwinds of some sort. But I was not able to keep the speed up becuase the OAT was 85, the CHTs were gradually approaching 410 and the oil temp was approaching 208, when I stepped in and backed the power way back. (down to 65 percent or so, then down even further as we were starting our descent.) After landing I got a little confused taxiing to Lynch aviation, but the ground controller was more than helpful. we refueled and got lunch. Heard about a RV-4? from Washington that went down after takeoff killing the pilot. We got the weather and filed for Coeur D'Alene.
While taxiing out for takeoff, a 747 asked the tower what kind of plane was taxiing off it's nose (us) tower asked us, and we gave everyone a brief Navion history lesson. I think the tower guy was the same guy we talked to on the way out.
After dodging thunderstorms and some moderate turbulence we were on the ground at COE getting fuel and pounding down the coffee. I got weather and noted we might have to deviate to get over the cascades and around the fires. Joe and I saw this large apparent CB looming up to FL 180? I thought it went to the ground, Joe initially thought it didn't as we approached we saw it was being generated by the fireline. We ended up going south direct to Seatac at 12500' when we got within 28 miles, ATC, who we were getting flight following from, asked when we were coming down as we were getting into their flow. I told him I'd descend through the Class B airspace if he would clear me. He did, and I set up a 500fpm descent. He came back asking me to expedite. I powered back as far as I dared and pointed the nose down. We were coming down pretty fast. I eventually entered the pattern at PAE, I was set up on a right base for 34L I didn't hear it right I was expecting 34R from the east, but tower corrected me. Then I was told to turn downwind for 34R they would call my base, well I coulnd't do a single turn to downwind, so I was confused. Eventually I was told to turn right do a 180 and follow the traffic (ahhh that's better) that made sense so I did it. And we floated down the runway. Oh well this wing working longer thing will take some getting used to I'm used to the wing just stopping, but these flap seals are screwing me up, my wing now works like a normal planes wing :-)
Joe and I were VERY tired on landing, but we both needed that vacation. All in all a good shakedown cruise. I had compression checks done, Cyl 3 was 77, there were 2 cyl. at 79, the rest were 78's Oil consumption held steady at 1qt/4.5hrs, the engine never did anything bad I'm starting to get happy with my Navion, FINALLY.Tim Corrie N5375K