@Antonio, thank you very much for a very insightful post. I found your explanation of relative pressure enlightening.
My aircraft is in maintenance (100 hours) right now and I can only agree that the way the exhaust is put together is a major contributor or accelerator.
We have found 2 leaks, one at an EGT probe and another at a flange assembly. The EGT probe leak would have fried the (new) ignition harness if we had not shielded the spark plug side . The heat shield was burnt!
The other leak would have caused damage too if the ceramic coated stainless steel shielding had not been added.
I fully agree with your word of caution about the “butterfly effect”.
Nevertheless I believe that we Extra 400 owners are playing russian roulette with the 321 stainless steel exhaust. The POH figures for leaning limits are mind boggling high and even with the reduced values that are propagated among our community (max TIT 1650 F) the exhaust literally melts.
We must also keep in mind that this is a liquid cooled engine. The airflow around cylinders is inexistent in comparison with an air cooled engine. as a result, the factory have had to put some stainless steel (not aluminum) shielding to protect the induction risers.
But I am taking your advice. I will not mess with the exhaust heat shield.
Rather, I’ll ask my shop to implement Extra’s solution: blow cooling air on the critical areas. Extra did this but not on all aircraft and did not document formally.
Beautiful plane. Beautiful light. And nice landing too :-)
Thank you so much :-)
You were hand flying; it looks like.
Nice avionics, too.
Thanks Peter. I was indeed “kind of handflying”
The STEC55X does not properly manage approaches – it intercepts badly. I tried it once in Geneva and got whipped by ATC.
Got used to flying by HDG and manually intercepting. It is quite fun actually.
I also like to fly it occasionally completely by hand, especially if the weather is rough because of the dreaded autopilot disconnect syndrome. “Here – your plane – too rough for me”. It is really not difficult, a matter of keeping calm and focused.
Avionics are doing the job indeed. I love the panel-installed iPad. My bet is paying off: tablet based software is getting better by the year and much to my surprise the integrated 4G modem is picking up some bandwidth up to … FL100. In a carbon fiber DUAL skin… go figure.
If my copilot is on board, we typically load a last Windy map and all METARs in Garmin Pilot during the climb.
I was also looking at Blitzer.de in case of thunderstorms.
Any other useful tablet based tools you can recommend?
I have the ADL150. It “just works”
Windy.com has transformed wx planning pre-flight.
Thanks Snoopy & Peter! I just downloaded rainviewer.
It is a great complement to Meteoblue which looks great but is notoriously inaccurate on occasion!
having actual precipitation data can be just the complement I need.
Absolutely love windy and it is getting better and better!
It’s boasting day!
Celebrating 500 hours since the major rebuild project of Extra 400 “Galatea”.
Yesterday (Nov 11th 2011) we had a challenging flight from LFEY, an Atlantic island off the french coast to ultimate destination LSGG Geneva with a fuel stop in between.
The flight was totally uneventful, except a massive tailwind – 240 knots ground speed but a big smile on my face!
Today as I was trying to learn from Dick Rochfort’s videos on youtube, I came across one of a cruise climb in a PA46 Mirage.
Parameters were real close to what we experienced yesterday, and Dick commented extensively on the settings, which made a comparison possible.
This was a great opportunity for comparing the operational benefits of a well tuned and healthy liquid cooled TSIOL 550 versus an equivalently powered air cooled engine.
Unlike most Extra 400 operators, I am actually a big fan of the engine, and I think it has fallen victim to poor manufacturing and terrible incompetence in the field, despite its fundamentally far superior design. Here the proof in a few numbers:
I am guessing that Dick was alone on board the PA46 (vs 2 persons and 50 Kg of luggage in the Extra 400) but he had almost full fuel tanks whereas we only had 266 liters on take-off. So let’s call this “roughly equal loading”.
OAT was ISA + 8 in both cases.
Both engines are 550 cubic inch turbocharged. The Lycoming of the PA46 has a twin turbo setup versus one “big” turbo for the Extra’s Continental
Dick explained that when doing a cruise climb he aimed to keep CHT near cruise values.
In order to do so, he limited power to 70% with a fuel flow of 32.5 GPH. His hottest CHT was 380 F.
The Mirage passed 12’000 ft at 131 KIAS and 450 fpm.
In comparison, the Extra was operating at 85% power according to the EDM 930 (don’t ask me why it says “85” – climb power should be 88% per POH).
Fuel flow was 126 liters or 33 GPH. Again very similar, but we were extracting about 300 HP versus 245 from the same fuel flow. >20% higher efficiency
We also passed FL 120 at 130+ KIAS but we were climbing at 1’000 ft per minute until reaching our cruise altitude of FL 190. This difference which can only be partly explained by the additional 55 HP.
And now the scoop: our hottest CHT’s was 255 F. Confirm: TWO fifty five.
I find it remarkable that the TSIOL 550 allowed a climb at more than double the rate of the air cooled engine with identical airspeed, fuel flow AND with massively lower CHTs. At 255 F, the aluminum cylinders are essentially taking a nap…
My experience is that the TSIOL 550 is a very good performer until ISA +10 (1000 fpm to cruise) then a decent one until ISA +15 (1000 fpm to FL 120-150) and a challenging ride above ISA+15, requiring very careful trade-offs.
This comparison was enlightening. I did not expect behavior in the climb to be so much better than the air cooled equivalent.
I honestly believed that liquid cooling was “only” superior in descent.
What a pity that they gave up making them before they figured out how to do it properly…