top cruise speed

[David Callon]

I have read several things about cruise speeds. So here goes.... what is the max mp and max rpm that I can continuously operate my pa30 at that will not be hard on my engines including turbos

[Zach Grant L1011jock]

David,
Max continuous power for a turbo PA-30 is 28" MP and 2600 RPM. Run the thing all day long this way, but beware of the CHT's. If you have a GEM or JPI engine monitor, you can adjust the FF to keep the temps undercontrol, and it will take a significant load of fuel, especially up high where there is less air to cool the engines. Running normally aspirated, you can run WOT, 2700 RPM. These engines are designed to do this. Do not baby the engies, run them hard. Takeoff full throttle, climb full throttle, reduce RPM as desired or necessary for turbo operation, lean to keep the engines smooth and cool. The true key to longevity in the IO-320 engines is regular uses. Do not let the plane sit. Go fly it weekly and manage power correctly and you will make it well beyond TBO if you started with a good engine.
-Zach

[Dan Johnson]

Zach,
Is the same true for the IO-540? WOT and 2700 rpm all day long? I have about 3 hours on my new engine now and have been running 2400 to 2450 squared. I have been staying @ 3000 msl. No leaning. Love the speeds. Been averaging about 170 knots. Want to go faster and make sure I break it in right.
Regards,
Dan

[MULEFLY]

Dan.. a seasoned old IA told me back when I had my IO540... "...you can run that baby at red line forever and it won't hurt a thing..." I will defer to the Naptown wizard as he has much more experience than I do...

That reminds me, we now have 3 celebrities from Indianapolis... David Letterman, Jane Curtin, and Zach... (ZACH is the best in my book!) Letterman used to be a weatherman on one of the Indy channels, Jane was "a dialing for dollars dolly" on a mid afternoon movie program. And sadly, Zach used to fly L1011s.

All the best!
Jim

[Zach Grant L1011jock]

Dan,
Yes you can run the IO540 WOT and red line all day long if you want to burn the gas! Pulling the rpms back does save some fuel, and quiets the noise a bit. As for break in, run the MP up and change the prop rpm occasionally, never less than 75% power with the MP being the important part as the cyl pressures are what force the rings out and create the heat that seats them and ensures long life and low oil consumption for your new engine.
-Zach

[Dan Johnson]

Thankyou Zach and Jim for your quick replys.
Dan

[9089P]

Hi Dan,

A frequent winner of the 99's air races held each year is a woman with a 260B. My wife asked for her secrets and her comment was to "push everything to the firewall and leave it there." She claims she tbo's her engines and I will say it is a sharp looking aircraft.

Good luck, Don

[N3322G]

Don, You are likely talking about Fran Bera as the 260B owner - short woman based at Gillespie. Firewall is not a problem with Lycomings. She's a very sharp very smart pilot and still holds some records in a Bonanza.

Have raced the Twin's engines since it came out of the factory. Have gone to TBO twice on the first set and once on the second set. Firewall on power and props - once at race altitude - lean to best power as seen on airspeed gauge - before all the fancy stuff. no problem.

[9089P]

Hi Pat,

Yes it was Fran, I have talked to her several times. Very interesting.

Don

[Dan Johnson]

Hi Don and Pat,
Thankyou for the information.
Dan

[David Callon]

well it sounds like everyone agrees on my pa30 run at 28" MP and 2600 RPM. Any other opinions

[Zach Grant L1011jock]

David,
Yes we agree, and I have no other recommondation EXCEPT...if you run it that hard...you will need to feed it. At those power settings the CHT's on #3/#4 will get out of hand very quickly iff you do not run at least 11 GPH per engine, and at higher altitudes it will be 12+ and cowl flaps open to keep CHT's below about 425 degrees. Cheap on the gas, and you will pay in parts, like Cyls and valves and rings and pistons...
-Zach

[15384]

Flying with Al Powers to Oshkosh from Seattle and back last year and seeing him operate over square, 2150-2200 RPM and 24" and then hearing these other stories about running them hard to make TBO I'm starting to believe you can run them anywhere and make TBO. Cause Al has operated at these power settings for the last 30-40 years and made it to TBO twice. He is on his 3 set of engines now. The one thing he does do is fly regularly and changes oil religiously this seems to be the real key to making it to TBO.

He swears that his plane flys a few knots quicker, smoother and quieter at these settings then any other. And after 40+ years and +4000 hrs of owning and flying his 64 PA30 I wouldn't have any reason to doubt him.

John

[Zach Grant L1011jock]

John,
I don't think anyone here is saying you MUST run balls to the wall to get TBO, they are just saying you can. You are exactly correct that regular use is key, regular preventitive maint. is essential, and operating within the design parameters of the engine is required. Getting an engine to TBO may actually have more to do with what one starts with than anything else. I have seen some pretty ugly OHs over the years that dhad no chance of making it to TBO next run because they were barely legal when they left the shop this time. Likewise I have seen some very well built engines survive years of abuse! Friction really is not a big factor in these engines as the tolerances are huge by comparison with todays automotive standard. Also the 2700 rpm red line (or 2550 for you 250 drivers) is about what your car is turning at highway speeds. It really is not that high. As with all air cooled engines, cooling is king however, and uneven heating or cooling, or operating too far outside design temps for extended periods of time will cause damage. Metelurgically speaking, cyl loose half of their strength at approximately 435 degrees CHT. Excessive heat does kill! If you are running hard, keep it cool!
-Zach

[T210DRVR]

Zach, does 162 KTAS at 10,000 ft, 2400 rpm and 23" MP on a turbo PA-30 sound about right?