Full power or not

[Taltruda]

Larry,

Here, read this

https://www.lycoming.com/content/tips-extending-tbo

I know it says that this article is directed at the TIO 540 J, but it also says that it applies to other Lycoming engines as well.

Go to the “Takeoff” section

“ TAKEOFF

Part throttle takeoffs should be avoided. The fuel injector metering jet is a two-hole unit, which is interconnected with the throttle. The secondary jet is fully opened only in full-throttle conditions. The richer fuel flow supplements engine cooling and deter engine damaging detonation.”

As for your temperature, I was referring to your EGTs, not your CHT. Watch your EGT at full throttle, then pull the throttle back an inch or 2 on the manifold pressure, and you’ll see the EGT climb. Back full and they cool. Your CHT is more of a function of airflow and mixture won’t move it as much as EGT do with mixture changes.

[rongawer]

Originally Posted by Taltruda

After 1000 to 1500 or so, then you may throttle back. But be aware that most engine failures happen during power changes.

My question is really directed at those who do throttle back - why? Why throttle back at all? And why, of all phases of flight, would you throttle back in the climb? What are you saving? Certainly not the engine, unlikely fuel (block-block) and absolutely not time.

Two things to make life easier. One: full throttle on take off and then don't touch it until ready to descend. Two: properly lean mixture through the climb and once at cruise and properly leaned (you are leaning LOP, right?), don't touch the mixture until shutdown. Your engines will run longer and cleaner, your flying will be easier, and you'll have consistent, if not improved, block-block economy.

[swjohnsey]

Originally Posted by rongawer

My question is really directed at those who do throttle back - why? Why throttle back at all? And why, of all phases of flight, would you throttle back in the climb? What are you saving? Certainly not the engine, unlikely fuel (block-block) and absolutely not time.

Two things to make life easier. One: full throttle on take off and then don't touch it until ready to descend. Two: properly lean mixture through the climb and once at cruise and properly leaned (you are leaning LOP, right?), don't touch the mixture until shutdown. Your engines will run longer and cleaner, your flying will be easier, and you'll have consistent, if not improved, block-block economy.

Do you really think any engine will last as long at full throttle and red line as at 50% power? I like your philosophy though and always make full power launches in the Corvette. My RV-4 has a hot rod IO-360 from Li-Con, dyno says 217 - 242 hp at around 2,800 rpm. I usually take off at around 25/25 which still give me 1,800 fpm when I turn cross wind.

[9GT]

Originally Posted by swjohnsey

Do you really think any engine will last as long at full throttle and red line as at 50% power? I like your philosophy though and always make full power launches in the Corvette. My RV-4 has a hot rod IO-360 from Li-Con, dyno says 217 - 242 hp at around 2,800 rpm. I usually take off at around 25/25 which still give me 1,800 fpm when I turn cross wind.

This threaded has a slight drift going on. The OP is questioning SOP for power settings during TO of his RV-10.

[rongawer]

Originally Posted by swjohnsey

Do you really think any engine will last as long at full throttle and red line as at 50% power? I like your philosophy though and always make full power launches in the Corvette. My RV-4 has a hot rod IO-360 from Li-Con, dyno says 217 - 242 hp at around 2,800 rpm. I usually take off at around 25/25 which still give me 1,800 fpm when I turn cross wind.

I can attest that I flew my Baron for nearly 2800 hours on the same engines in the manner I described with great success - those were IO-550 Continentals, but Lycoming clearly states their engine can run at 2700 rpm continuously, and do so to an expected TBO of 2000 hours. So yes, it will last - and last well. The biggest degradation of aircraft engines is not from being run hard, but sitting idle, which is to say that if you want your engine run a long time - run it a lot.

By the way, your response is mixing full throttle, rpm and percent power. You can actually have full throttle, redline and 50% power - [along with many other combinations - and that is getting off topic, though I'm more than happy to discuss separately]. One thing to consider for folks that want to pull the throttle back: the lowest air friction and highest volumetric efficiency of the throttle is wide open. If you're running at or above 7500' MSL (the approximate critical altitude of a normally aspirated engine) with the throttle at any position less than full open, you're choking the engine and not running at its most efficient point.

The OP's question was answered and I stand by the comment that taking off at full throttle, full RPM and properly set mixture is the right way to take off. And then in cruise, leave the throttle full, set your RPM as desired, set mixture - and then leave it alone and enjoy the ride.

[leok]

A tap of the brakes to get the nose wheel set straight, then bring it smoothly up to full power while adding a boot full of rudder. I have never needed brakes.

I typically bring it back to 23 inches and 2450 RPM at 1000-2000 AGL depending on what my plans for the flight are.

[rongawer]

Originally Posted by leok

A tap of the brakes to get the nose wheel set straight, then bring it smoothly up to full power while adding a boot full of rudder. I have never needed brakes.

I typically bring it back to 23 inches and 2450 RPM at 1000-2000 AGL depending on what my plans for the flight are.

Ok, I'll bite....why are you "bringing it back to 23 inches"?

[erich weaver]

Originally Posted by rongawer

Ok, I'll bite....why are you "bringing it back to 23 inches"?

I’m not leok, but guessing that because if he didn’t the density altitude would be low, manifold pressure would be quite high and the detonation margin would be slim or nonexistent.

Erich

[TShort]

I take off with full power.

As others have said, if you corncob it right from the get go, you need to be on your toes as the rudder becomes effective. I add power gradually.

I climb at full power to at least pattern altitude. Why not? Part of the fun of the RV is climbing at 2000'+/minute.

[rongawer]

Originally Posted by erich weaver

I?m not leok, but guessing that because if he didn?t the density altitude would be low, manifold pressure would be quite high and the detonation margin would be slim or nonexistent.

Erich

Erich, that is an interesting guess, and I can understand that you, Leok, and possibly many others - believe that is true based on traditional training to "Power down and don't go over square, and set for 25/2500 to climb". I experienced that same training myself several decades ago. However, the IO-540 is designed to run at sea level, where cylinder pressures are the highest, at full throttle at redline continuously - there are no five minute time limits or other mysterious limitations that get taught, such as you can't operate "over-square". The only MP vs RPM limitation I'm aware of is 27" MP pressure at or below 2300 rpm on certain 540 variants, but not the D4A5. Assuming you have a properly operating fuel system and cooling flow setup, you will not be limited by detonation margin at full throttle and RPM. You are not "babying" the engine by restricting its power in climb.

The idea of pulling back the throttle after takeoff is an OWT based the history of radial engines that keeps getting taught, but should not be.