Flyingfish wrote:
I ‘d love to come visit you and get some education on high power LOP if I may
Sure! It would be awesome to ride beautiful Galatea with you! Never flown (or been near for that matter) an Extra 400! It’s kind of a spaceship when compared to our trusty old 210.
However, now you have your new or overhauled cylinders+pistons is the wrong time to fly low power or LOP. You really need to fly ROP 75% the first hour except for landing. Then you can alternate 75%-65% for at least 5 more hours, and minimum 65% until break-in. Avoid long, low-power descents.
You need those high ICP’s for good break-in. It usually takes about 5 hours or up to 15 to break-in and you will need to change the oil after 15-20 hrs, once you are sure all is broken in. Only then you can start tinkering with LOP. In your case a big part of the initial break-in has been run by the shop, so you are a few hours ahead in the process and your risk of getting it wrong is lower.
As to CHT’s, there are two schools in the air-cooled big-bore Continental gang:
-Those who say the lower the better as long as you are above 200-250F
-Those who say you need minimum 300F and ideally 370-380F.
I am personally, together with Continental Motors, in the latter gang. As to Continental, I leave it to you as to how much to trust them since they are the ones who make a business selling us cylinders that last 600hrs on Turbocharged big-bore 520’s and 550’s. What I have found is that the amount of lead deposits in the exhaust (and spark plugs) is much higher with lower CHT’s. The typical issue with that is that sealing of the exhaust valve seat and wear on the valve guides gets worse with increased deposits. Maintaining sufficiently high CHT’s ensure those deposits are minimized. THis of course has to be combined with fuel richness: too rich ROP also increases deposits unless you keep your CHT around 380, too lean will mean fewer deposit creation but also too low a CHT. The most typical failure mode on air-cooled cylinders on this type of engines is exhaust valve leaking, so maintaining a reasonable CHT should help with that. Too high, and you will increase guide wear and risk cracks in your head. Too low and deposits will increase.
I do not know how the above translates to your liquid-cooled engine. Does it have a thermostat to keep CHT stable? Where do you measure CHT? Cooland or a sensor inserted in the head like air-cooled cyls? What was valve-to-seat seal like on the removed cyls? ie were compression checks good and where were cylinders leaking through? Piston rings or exhaust valve? That will give you an idea. If you were leaking via rings, then probably you were too soft on the engine: typically you want to do most cruise at 65-75% but definitely no lower than 65% on TC’d big-bore Contis. If leaking via valve seats then all you can do is keep the right temps and the right mixture until eventually some valve work will be needed.
I am sure your cylinder balance will be different on the new engine, but you’ll have to wait for break-in before you really find out. You may have to tinker with GAMI injector setting and GAMI will help you with that…but that will have to wait till after break-in.
I do not know how the above translates to your liquid-cooled engine. Does it have a thermostat to keep CHT stable?
> yes to an extent: coolant temperature is closely related to CHT, and there’s a thermostat in coolant that covens cooling at 180 F.
Where do you measure CHT? Coolant or a sensor inserted in the head like air-cooled cyls?
> Sensor rings on spark plugs. Plus a dedicated probe for coolant.
What was valve-to-seat seal like on the removed cyls? ie were compression checks good and where were cylinders leaking through?
Compressions were still solidly in the 70s, with a random pattern from one test to the next to illustrate the rotating rings theory…
Piston rings or exhaust valve?
I found some oil inside the cylinders but also had some deposits on valve stems.
That will give you an idea. If you were leaking via rings, then probably you were too soft on the engine: typically you want to do most cruise at 65-75% but definitely no lower than 65% on TC’d big-bore Contis.
> My typical cruise was some 60% ( 29 inches, 2250 RPM, 72 liters, TIT 1650)
Flyingfish wrote:
Compressions were still solidly in the 70s
With compressions that good, what you are doing is working. 60% cruise is a bit low for my liking in terms of keeping your rings seated, but being ROP, it is clearly good enough.
Also, good to make sure you use correct .060" orifice in the diff pressure tester for cyls >5" bore (not the 0.040" orifice).
Recently two of these rare airplanes have appeared on planecheck.
A 1999 model and a 2001 model. Asking 480k and 296k respectively.
There is also a 500 listed in the high 800k’s. But that one has only about 450 hrs TTSN.
I think I know both 400s. There’s also one for sale in the US by the way – N70HG.
N400YY (the 2001 model offered in France) has the same upgraded prop as mine and some other improvements which made the previous owners happy in terms of sustained climb performance. Being N-reg, this would be my first choice, even more so considering the huge price gap with the Romanian plane.
The Extra 500 presently for sale for 900 K Euro is the beautiful former Swiss bird which I think was previously owned by Paolo who posted some gorgeous pics here.
One has to be aware of the fact that this roomy, very sleek, comfortable turboprop has no FIKI certification and that FL200 is its “practical” ceiling by design.
FL200 is frequently ok in Europe if you’re willing to dodge TCU tops, but no FIKI certification is a real bummer – I have heard a first hand report of engine flameout in icing in an Extra 500, so this FIKI issue may not be dismissed as merely “missing paperwork”, it is a major shortcoming.
In short, I would not trade my 400 for a 500… of course its piston engine is less reliable and noisier, but its balanced performance and FIKI certification make it a more capable ride for year round travel despite its shorter legs. The liquid cooled turbo Continental runs very smooth so that no vibrations at all make it to the cabin.
Honestly, the 400 is a lovely and very capable plane, BUT it is still today in beta stage.
Don’t touch it unless you’re happy to manage maintenance, find parts and pay a lot for them.
Most of us owners have become greedy parts collectors ;-) I just got a shipment of used stuff from a friend in the US.
A good 400 will reward you with a 20 minute climb to FL200, 50% faster descent and 200 knots+ cruise speeds at 75% power, in a roomy pressurized, air conditioned cockpit and cabin that would be perfectly fit for a jet, once suitably upgraded.
A truly unique package at the overall cost of ownership of a recent SR22 turbo (including capital).
Just don’t buy the Extra 400 for business use, it is only appropriate for private travel where the worst you can miss due to AOG is a wedding party on some lovely Greek island …
Flyingfish wrote:
the worst you can miss due to AOG is a wedding party on some lovely Greek island …
Like Mamma Mia? Would be a pity to miss though.
I’ve awakened as my P210N has suddenly become worth a lot more. I am making an offer to trade it plus cash for N70HG. I’m not sure why this EA400 only has 252 hours since new but I guess I will find a story there. Fingers crossed this deal comes off. I like the idea of the EA400 very much. It used to be registered as D-EXYP
Do you want to fly an Extra400 or only repair and sit in it?
I definitely want to fly the EA400 and not just repair it. To me it represents where the P210N could have gone and is an interesting alternative to the Malibu/TBM route that was taken by the bigger makers.
Lets look at the EA400 compared to a later 350HP Malibu Mirage
_________EA400___MirageMTOW___4400#____4340#
Useful___1060#_____1260#
T/O Dist__2920ft ____2977ft (to 50 feet)
75%_____223KTAS__212KTAS
From the specs we can see the EA does pretty much what a Malibu will do excepting a Malibu has a 43 foot wing whereas the EA400 is only 37 feet. So the EA400 is a little faster but cannot carry as much as the Malibu. However (amazingly) stall speeds are exactly the same and EA400 has slightly better short field numbers than the Mirage.
So with more work and weight reduction its easy to see where the EA400 was going. And with a TSIOL engine, takeoff fuel flows are significantly less than the TSIO engine. This is because so much extra fuel is needed to keep air cooled engines from detonating than TSIOL. This helps a claw back the lower payload. Less fuel is needed for the same mission. A lot less. My climb rate in the P210N is around 350FPM to 20,000 at ~30GPH. The EA climbs twice as fast at around 35GPH. I burn 30 gallons to 20K whereas the EA400 only needs around 18 gallons to the same altitude. That’s 12 gallons (72#) less for the EA400.
So yes, I want to fly.
Do not touch this aircraft! A local pilot had a 400. It was rather cheap so he assumed if he had to fix something it would not be too bad. It was a horror stoy. gear internals broken on landing, engine caused serious issues etc. Many parts like cylinders, engine mount, gear are super hard to come by and he was in Germany where all the original companies are. Invoices have been eye watering even for aviation standards and the thing never flew properly. The idea might have been good but that plane was never engineered to the end and never matured. Keep the 210 and be happy or upgrade all the way to a PA46.
