2021-11-05 TestFlight 29 – The Final

The final flight. As I have nothing else to test at this time, I decided to just make it a fun flight, to celebrate all the hard work that it took to come this far.

I departed runway 32 to the east, and then turned north. A beautiful day, blue skies and almost no turbulence, a nice way to end 10+ years before I could get to the beginning of the real mission of the aircraft. Many days, weeks, years of designing, building, and testing, we are now starting to enjoy the fruits of all that labor.

And not just my labor, but that of those that surrounded me and the hull. From neighbors that helped my turn the plane upside down, to Roy and his truck and trailer that I used to move the plane multiple times, to JD Upholstery, who as a team helped with, and installed the interior. Jimmy, who unfortunately passed last year will never be forgotten as we will enjoy his work for years to come.

Then there is Tim Hass with Approach Fast Stack, who helped put the Avionics package together, and who has helped me through a few technical issues through the years. Always quick with an answer.

While flying this amazing machine, I started to think of all the other VELO pilots, the ones on the VOBA, those who I met at OSH, Rough River or somewhere else, the Factory at Sebastian, especially Scott Swing, John Abraham, Ingrid, Chad, and especially Art, who had to deal with my nonsense and find the best person to talk to.

A good friend, Stephen Port, EAA member and my former Vice President, was instrumental in my painting endeavor. He helped me overcome my resistance to painting. I am not a painter, at all, and yet he gave me the hints I needed to prime the aircraft. I hope to lean on him when we finally put the final coats on.

The past years I had some big help from especially two friends, Aad Zeeuw and Howard Kohnstamm, who assisted me in the years of COVID to finish this project. Without them, I might still be in the hangar, trying to convince myself that someday it will be finished. They set a date, December 31, 2020. Although we didn’t make it, it surely helped with keeping the pressure on and pushing forward.

But the biggest thanks go out to , you guessed it, my family. Dana has been rolling her eyes through the years, about design questions I had for her, the plane in the garage being in the way, me late for dinner as I was attaching something and it had to happen now.. My kids, having pretty much grown up with a plane in the garage, having to explain to their friends about their dad building an airplane.. and some flying trips we have done in the meantime in other aircraft. Thank you !

All these people joined me in this last test flight, just finishing the last point 8 of and hour, to get past the 40 hrs required testing time. It is an accomplishment, they say, but they forget often it was because of them that I got it achieved. It’s always a Team Effort !

I owe all of you a flight.. until then, Thanks !

Patrick

2021-11-05 TestFlight 28

To finish the turbo testing, I wanted to fly another box pattern, so I could check speeds, endurance and fuel flow. I also wanted to check on altitude once more, to see when exactly the Turbo started to loose pressure, i.e. critical altitude.

I departed Smyrna runway 32, and headed eastbound. a strong southern wind pushed us more northeast bound. I climbed straight to 5500Ft MSL, and remained there until the turn to the westerly headings. I leaned the engine and as always the #6 cylinder head temp ran hottest, just over the 435F eco limit. With a OAT of 16C, something to keep in mind.

My further climb took me to 10,500Ft MSL. I did note in the later stage of that climb, that the turbo didn’t keep pressure once again. This will need to be adjusted. Reading the data later showed that at 8200 ft MSL, the pressure started to drop off slowly at first, but steady later on, until 27″MP at 10,500ft. Still much higher than the 22″MP without the turbo selected ON, but not good enough according to the engine manual. Of course, I did have to make some adjustments to the engine, which will play a role in its efficiency and the deviation from the manual.

I stayed at 10500 Ft MSL, and flew west then south. The wind clearly out of the southwest pushed our track as seen above. I had ordered SiriusXM for the plane, and halfway in the flight it started populating the channels, and I was able to listen to the music as I was flying. A nice feature for the family.

As I started my descend to Smyrna, TN, I listened to Nashville approach and noticed one of my friends flying towards Lebanon TN airport. As she cleared the BNA airspace, she switched as did I and I started tracking behind her towards the field as I descended. I passed her by at 170ktas on her right, and then moved on to the Smyrna Airport.

After that encounter, I returned to base, and landed on runway 32 and taxied to Hollingshead one more time for a final test fuel load. I have 0.8hrs to complete.

2021-11-04 TestFlight 27

After taking an hour break at Hollingshead Aviation where I get my fuel from, I decided to take another flight. I had topped off the tanks and it was time to stop at a few airports within my box. One of the tests would be the length of the runway, while I would also check for brake fade and operation during multiple landings in one flight.

I took off from runway 32, A8 intersection. I turned east and then northeast as I climbed to 5500 ft MSL. My first landing would be at Jackson County TN, a 3500ft long strip which would give me a good idea how it would be to land in 5NC5, The Duchy Estate NC, where we have bought land to build a house and a hangar soon. Jackson County is nestled in the hills and not easy to approach. One way is too follow the river around the bend and you will suddenly come upon it. I decided to come over the hills on a steep approach, straight in. This will simulate my landing in 5NC5 a bit more, as it has a small hill in front of the approach end.

My approach at 100 kias was standard, and I touched down within the first 500 feet, and rolled to a stop with at least 800 ft of runway left. I was pleased. A good data point. I backtaxied and noted that my right brake was dragging a bit. I departed the runway 01, at 70kias I pulled the nose off. It didn’t climb as quickly as I had hoped, as it didn’t accelerate and climb. Next time I will keep longer on the ground before rotating. Nevertheless I got above the trees easy and followed the river as I climbed over the ridges of the surrounding hills.

From there, I flew further east, to Rockwood airport, where I had been before a few times. I once again climbed to 5500 ft MSL, and then descended rather quickly to the airport. With no-one around, I made a quick touch and go, and climbed north before turning west towards Crossville airport. I got some training with the navigation on board as well.

I stayed at 4000 ft MSL, as the clouds had drifted lower over the ridge and visibility was reduced in a light rainshower, I was almost lined up with the runway 26 when I arrived, and made another touch and go, and climbing almost straight out, navigating to Smyrna airport at 4500 Ft MSL. I landed and taxied to the hangar.

Once I arrived there, the brakes were hot enough to tighten the grip so it was hard to move the plane 10-15 minutes after I came to a stop. Overnight cooling resolved the problem.

2021-11-04 TestFlight 26

Once I had the Turbo working, and I was happy with its performance, it was time to finish the hours on the Flight Testing.

I made the decision that high altitude testing and endurance testing would be combined and a baseline for fuel flow and usage could be established. So the plan was to make an extended flight at altitude. It would give me great data on the turbo operation and the fuel use associated with it.

So after a long taxi, I took off from runway 32, and head eastwards. During the inital climb I turned on the Turbo and didn’t turn it off until after landing. I climbed to 3500 Ft MSL and leaned the engine.

After turning northeast, I decided to go more north and climb once again, to 6500ft MSL. The Turbo MP remained oscillating around 29.0 “MP, a little high but workable. The pressure sometimes got close to 31”, which should be the cutoff, but I am not sure if the dump valve actuated and thus the MP went lower, as the system is designed to do, or the controller responded and lowered the MP. Either way, the Turbo pressure remained within limits.

What was also clear, and it showed later in the data, that at the higher altitudes, the MP is more stable. Not clear if that has to do with RPM setting, leaning, or any other factor.

After a flight west I flew to the northwest side of my testbox, and then descended towards Smyrna airport, and landed back on runway 32. I flew another 2.0 hours and am now getting close to the 40hr minimum fight time. I hope to finish testing this week.

2021-11-03 Test Flight 25

Today started with correcting the Turbo settings as I had made an error in reading the maintenance manual. Instead of 28.5’MP, during the test below 1500ft MSL, it needs to be 29.5″MP! a full inch more. So I removed the Cowling once more, and hooked up the hoses for the test setting, and rolled the plane outside for a testrun.After three starts and runup to 26″ as prescribed, I finally had the setting to 29.6″MP, very close to the books required number.

I closed up the cowling after putting everything back where it belonged, and added engine oil. I forgot to check the Turbo oil, but it was close to 2/3s last time I checked I was now ready for my testflight, with turbo power!

I taxied out to runway 32, did a short runup with 70 gallons of fuel, me and 100lb in the front seat, and once cleared for take off and departure to the east, I lined up, and as per the manual, left the turbo off below 1000ft MSL field elevation. Max power gave me 28.8″ MP with 2670RPM. All temps were in the green and the take off roll was nominal.

Climbout was a normal 900ft/min. Reaching 1000Ft MSL, I turned on the Turbo switch and after about 5 seconds I noted that Turbo started to add some MP.I climbed to 4000 ft MSL initially. The Manifold Pressure remained at around 29.0″. The turbo is finally working!

I then decided to climb to higher altitudes to see if the turbo remained holding pressure. I held 29.0″MP until 8000ft MSL, after which it started to loose pressure. At 9500 Ft MSL, I still had 27.4″MP while in turbulent conditions and I decided to descend.

I remained airborne for a 2.0hr flight, and burned 35 gallons of fuel. just about 16,5 Gallons/hr.

Unfortunately I didn’t get my video and I forgot to add my data card for this flight, so no capture of any information was done.

Note: The data card got corrupted. so therefor only the first part of the flight is visible on both pictures.

This test flight concluded that the turbo finally worked, although it is not quite as powerful at higher altitudes as the critical altitude is 8000Ft MSL at this time. I am happy to see an airspeed increase associated with the turbo being on of about 13 knots at 6500ft MSL.

2021-10-29. Maintenance.

Two days after my failed turbo test, I came back to the hangar and once again removed the cowling. I first thought to remove the top only, but then decided to take both off.

I double checked the throttle arm hitting and pushing in the transfer valve. It still operated as it had before the TestFlight. I now needed to adjust the throttle arm while the cowling was removed.

Now, to my next item.. whether to remove the controller or see if I could adjust the controller setting. For the adjustment, there is a procedure in the maintenance manual, whereby a few hose connections are loosened and swapped if the field elevation is below 1500ft Msl. So, book in hand, I disconnected, rerouted and swapped the hoses before reconnecting for the test setup.

At this point, Aad arrived and we pushed the plane outside, into the light rain. Chocks in place, I started the engine for the test. It required to throttle to 26.0” manifold pressure with the turbo switch OFF, locking the throttle and then turn the turbo switch on, and observe the manifold pressure. Ideally, it should start indicating 28.5”. At 30.5” the test should be aborted and the set screw turned counterclockwise to adjust down to 28.5”.

I pushed the throttle up to 26.0”, overshot a little, finetuned and tightened the friction lock on the quadrant. Then I switched the Turbo switch to ON and waited… and waited… and…. Clearly my turbo never kicked in. Bad controller, or bad setting? I shut down and opened the cover on the controller where the set screw was. I turned it clockwise 3 whole turns, knowing it would 99% be way too high.

I started again, now a warm motor (I got to practice my hotstarts a few times this way – I am proficient again) and once again performed the required test. Once I hit the turbo switch to ON, it took about 2-3 seconds and the turbo definitely kicked in, I heard the turbo spool up, and I saw the pressure steadily rise to 30.6”, before I could throttle back to remain within limits. At this time, I also had very hot CHT’s and decided to take a break to cool the engine before another runup.

After about 45 minutes hangar flying, we returned to the plane, reset the setscrew back one full turn, and tested once again. This time the manifold pressure was pushed up by the turbo to 29.0”. After shutdown, another minor 20 degree turn CCW was made, and once more tested. The result was that we now receive 28.6”MP in the test procedure where the book requires 28.5”. Close enough, and Aad and I pulled the plane inside.

Together we exchanged the hoses back to the original connections, and then worked on the throttle arm, to adjust the idle lower. This did offset the max power setting a bit, but I had noticed before that this didn’t seem to make a difference at all, for 33 hrs of flying in that configuration I got to the required 28.5”MP with no problems, with engine temps within limits. After a final check, we closed the cowling.

Unfortunately, the weather was inclement enough that I was not able make another TestFlight. But I am confident that next flight we will see good results. We have shown now that the turbo works, we thus know the waste gate operates, and that means the controller now works. All that together with a reseated transfer valve should make this work. Of it isn’t, I am confident enough to say that the transfer valve will be the problem at that time…. But let’s not get ahead of ourselves.

Next week will be exciting..

OOPS… not too fast… Reading is an art..

NOTE :

As I finish this write up, I got back into the maintenance manual to take pictures of the text I referred to.. while trying to mark the important partitions, I noticed I didn’t read my instructions well. What I actually did, was mix up the above 1500 ft MSL procedure with the below 1500 ft MSL procedure.. .. .. I actually need to reset the manifold pressure to 29.5” !! And not 28.5”… ugh.. so next week before flying we will revisit that and adjust one more time..

Maybe the excitement weakened my reading skills. Who knows..

2021-10-27. TestFlight 24.

This test would be to test the turbo system, and other engine settings, mainly throttle. I also wanted to check to see if my magnometer issue returned from the last flight, where I experienced a mismatch.

The startup was quite normal, but right away I noticed the very high Idle setting of 1050rpm. I will need to adjust that once I return. I taxied out, performed a runup and ATC cleared me to taxi to runway 32, ideal for a “adjusted engine” take off. Another short runup was performed and no magnometer mismatch this time.

I decided to stay in the pattern for at least one circuit before I would venture away from the airport. I was cleared for take off following a slow archer. I added T/O power, and I got 28.4” manifold pressure, pretty nominal. Halfway in the roll, at 40 knots, I turned the turbo switch to ON. Manifold pressure responded and I received 29.6” pressure. Other engine parameters were as expected.

Airborne at 80 kts, nose wheel at 75kias. Accelerated to 100 kias, and climbed with 900 ft/min to 2000ft, for a faster circuit to see how the engine performed. I requested a low approach, approved and started my descend back down. All the while manifold remained at 28.9”, a little higher but it made me smile.

After the low approach and initial climbing I requested a turn to the east, and was approved via a Right turnout. I continued the climb and stayed just below the class C until passing the boundary and continued the climb, while maneuvering a little more north for inbound traffic to the field.

At 2500 ft I started to notice that the manifold pressure was diminishing slightly. By the time I got to 4000ft MSL, I was down to 26.7” MP. Clearly I was still losing pressure. No Eureka moment..yet.

I flew a little longer and tried turning the turbo switch ON and OFF, and measuring differences in MP. There seemed to be no pressure increase at all..

I landed after 0.7hrs airborne and shut down at the hangar. I would be down to my last option, that I know to check.

2021-10-26. Maintenance

After arriving home after my work trip, I returned to the hangar and removed the cowling, and checked the transfer valve. It was not operated by the throttle movement at all. Maybe finally the eureka moment we all waited for.

I first decided to adjust the throttle arm movement as I had noticed that my idle was high, about 850RPM. The book calls for 675rpm. I also noticed that the max power stop would not be reached. So after some back and forth, I got to get to max throttle stop setting.

From there I started to adjust the transfer valve so it would be pushed in according to the manual, approx. the last 0.75” of throttle travel. The Ubracket was tightened and the bracket itself needed some bending, that obviously had been done before by the former owner. Eventually, the valve lined up with the throttle eyelet perfectly and was operated and tested many times.

With high hopes I returned the next day to the hangar to close the cowling, after doublechecking my work. The moment of truth, another TestFlight.

2021-10-23. Flight Test 22 and 23.

Today I tested higher altitude Turbo operation.

After a lengthy traditie, I departed runway 19 to the east. #5 CHT was highest before T/O roll at 389F. Climbing at 900 ft/min, at 118 Kias.

I departed southeast and climbed to 5500 ft msl, and made some measurements. During the climb, I noticed less MP oscillation amplitude, but still present. Once at cruise, I sped up but noticed that the MP still had dropped a little more than 1,5”, but the speed increased somewhat better than normal, now indicating 149ktas. I stabilized the flight and with the help of the autopilot I noticed very small MP oscillations while level straight and level. The RAM Air inlet does seem to build some higher pressure, and some more laminair flow to the turbo compressor side, making for better performance even if a little better efficiency.

After a climb to 6500ft msl, I noticed that the MP dropped to 26.0” and remained steady within 0.2”. Very stable air made for a very smooth flight, which may result in a steady MP as well, but I believe that the turbo improvement has effect.

I descended and landed at Murfreesboro TN MBT, using 3/4 of the 4K ft long runway, and visited a friend who was holding a Young Eagles flight day. After an hour plus, I restarted the plane without any problems and taxied to runway 18. Runup was completed without items, and I departed south. At wheels up, the engine seemed to momentarily overspeed, but rpm remained at 2680, and no changes in any other engine indications. I wonder if the turbo kicked in for a short boost, but can’t be certain.

I did climb with 1300 ft/min, at 108kias, which seemed more than usual. I leveled at 2500 ft and turned northwest towards Smyrna, holding 28.0” MP and 2500rpm giving me about 145ktas.

I did get a new problem I had not seen before. The G3X noted a HDG comparison fault. The copilots hdg was 30 degrees off from the rest, and remained like that. Later I also noticed that the attitude was not correct. Next flight I will have to check if this continues.

after a short hold I entered the class D and setup for LH downwind 19. I landed and could have taken runway 32 for taxi.. my landing technique is improving, and I will start to slow another 5 knots to see if I can reduce landing roll even more while still have good controllability during short final.

In conclusion, after three flights with the new setup, is that performance is enhanced but not quite where it should be. The next step might be to replace the turbo controller and check the electrical turbo system once more, to double check its working as it should.

But then I dove back into the Piper Aztec engine maintenance manual. One item that I had not paid much attention to, because I clearly didn’t understand the workings of it, was the sense valve that is operated by the throttle in max setting. I copied the following passage :

Reading this, seems to indicate that the valve needs to operate in order to get the 28.5” MP. If it doesn’t, I seem to understand that the controller doesn’t sense enough and uses ambient air pressure, which drops the manifold pressure even if the turbo is operating. This seems to match what I am seeing, some higher than ambient Manifold Pressure, but not the 28.5” it should hold until critical altitude.

Later, it also describes how it creates a lower critical altitude and power and fuel efficiency. This all seems to match what I am experiencing. Also the manual warns against replacing controllers before adjusting this switch.

2021-10-22. Flight Test 21.

This was the first flight after turbo manifold modifications, which I hope will give more flow to the turbo, and laminair so I see less oscillations in MP.

The improvements included a new turbo manifold snorkel, to provide better flow from the engine air scoop to the turbo compressor inlet. I also taped up all the gaps on the wing, and canard cover.

Startup was nominal, and I was told to taxi to runway 32. A short runup , with nominal engine numbers, and I took off to the east.during the take off I decided to leave the turbo off as per the engine manual.

At 1000ft msl, I turned east, turned the turbo switch on and pulled the prop to 2550 rpm. The turbo seemed to hold pressure and hold the MP at 28.5”, or very close to. During climb to 3000ft msl, a slight reduction in MP was noted, but the oscillations had greatly reduced. The controller seemed to hold the 28.5” without issue.

Once level I sped up and started to reduce the prop rpm. Again, the oscillations observed earlier seemed to have greatly reduced, and the pressure seemed to be up somewhat, but it had reduced somewhat.

After the overcast rose, I climbed to 4000ft msl, just below the layer. Once again, noticed that the MP had reduced but the oscillations were much less than before. After a box flight I decided to go to Lebanon airport for a landing. Getting closer, I changed my mind and turned back to Smyrna. During my RTB, I got a cautionary Pitot heat warning, a new one not seem yet. The outside air was 8C, and I did hit a whisp of a cloud. I will read about the caution some more to understand the trigger. Did turn it on, a d several seconds later, the caution was cleared off the screen.

I landed on runway 32, using about 2400 ft landing roll.