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Full power or not

rvdave

Well Known Member
The rv10 has plenty of power on takeoff, does anyone not use full power at takeoff? or what is your protocol after immediate departure?
 
does anyone not use full power at takeoff?

I only used part throttle at the initiation of the takeoff roll-----once I was sure the engine would take the throttle and I had rudder authority-----balls to the wall.

This is how Mike Seager teaches you to fly the 10.

In addition, I was flying out of a relative short field, which was in the bottom of a "bowl"---low hills all around.
 
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not a -10 but the principle is the same: usually flying solo and the TO at my field is done at 24/24... less noise, lower Ts, less fuel, and a couple of KTS lost.
Keeping the full power for the short and rough grass field, or when heavy.
Once outside the zone, retired cruise settings such as my typical 19/20.

My engines loves me... maybe :)
 
Full power always ? don?t understand why you wouldn?t but that?s just me. I do smoothly and deliberately add power to the stop. IOW I don?t slam it forward.
 
Agree with Larry

When applying Full Power from standing I found myself using the brakes too much to try to keep on centerline. Besides it looks Squirrel-y I now ease in the power steadily until rudder authority and then max power.
 
When applying Full Power from standing I found myself using the brakes too much to try to keep on centerline. Besides it looks Squirrel-y I now ease in the power steadily until rudder authority and then max power.

While I haven't tried it yet, I am told that a modified short field approach works as well. Advance to 2000+ while on the brakes, then release brakes. It makes sense, as the rudder would have a lot more authority then. I just haven't encountered a runway that wouldn't accommodate a slow acceleration.

Larry
 
I smoothly advance the throttle all the way to max. Maybe a carry over from my 182 days, when the carb had an ?auto-enrich? feature so CHTs were actually lower at full throttle than at a bit less. The -10?s rudder authority is very good - I never have to tap the brakes on takeoff except perhaps initially in strong x-winds. I keep my heels on the floor, don?t use brakes unless full rudder isn?t enough. Usually reduce power going thru 1000? AGL.
 
Lower temps

You should always use full power for takeoff. If you are using partial power thinking that your are babying the engine and making it last longer, you may be doing the exact opposite my not using full power. Carburetors have an enrichment at WOT, and if you use partial power, you aren't getting that cooling fuel. Also full power helps keep ring seal and prevents glazing. The engine is rated for full power..you aren't going to hurt a healthy engine by doing it.
 
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Smooth and steady full power on my takeoffs and I kept it there until I reached pattern altitude,,,,which does not take very long in the RV-10! (providing there is no noise abatement procedure like there is over at Canton-Plymouth Mettetal Airport, 1D2)
 
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Since human factor makes us all creatures of habits, you may end up conditioning yourself to take off at partial power, even when you really need full power. Explain that one to the FAA. Everything I have been told and that I have read, our engines are designed to run at full power all day. So why waist horse power on your take off.
 
I don't believe I am babying my engine and I don't believe that an inch of MAP below WOT on takeoff is harming my engine. While I sometimes use WOT, I don't believe that I am harming the engine or creating risk with a 5000' runway and 90% power. I have been doing this as a new RV10 pilot to help my directional control. Just haven't established a habit of pushing in the rest of the throttle mid way down the runway. I suspect that will change as teh summer approaches and my available power drops off. In the winter temps, 90% power was plenty. Still way more acceleration than my 6 (320 & FP)


Larry


That last inch is where the enrichment fuel is.. take a look at your egt at wide open, then throttle back an inch and watch the temps climb. You should use full power on piston engines for takeoff. Yes, go nice and slow applying it. . Like a 5 second count, or wait it'll you get good rudder feel before you go full, but you should go full power imho.
 
I never liked cobbing the throttle on the takeoff roll. I've always smoothly advanced the throttle to start the takeoff roll. That being said, yes. I was taught full power to climb on take off. Its easier on the engine.
 
What are you saving?

I'm still building my 10, so I can't speak to how I fly it...yet. But I don't see the benefit of taking off with anything less than full throttle. I've been flying large continentals and lycomings for many years and my method is to apply full throttle and don't pull the throttle back until I'm ready to descend.

If you are flying a normally aspirated aircraft, your power is reduced automatically as you climb, so pulling the throttle back just compounds this reduction.

Even more so, if you are flying a Lycoming IO-540-D4A5 engine, which most -10's have, then it is rated to fly at 2700 rpm continuously at full throttle - and the best way to ensure good cylinder life is to run your engine hard. An excerpt from the operating manual to ensure good ring seating is "Climb to cruise altitude at full power and operate at 75% cruise power"... let 'er rip tater chip.
 
When you are flying a 150 you need full power. When I take off at 25 x 25 and climb out at 1800 fpm I figure that is enough.
 
John Deakin's articles are great. A short quote from him answer's the OP's question, and pretty much sum's it all up: "With all aircraft engines, use full available rated takeoff horsepower for all takeoffs. I cannot think of a single exception. You are usually not being kind to your engine when you use less, and you may very well be mistreating it when you do so."
 
John Deakin's articles are great. A short quote from him answer's the OP's question, and pretty much sum's it all up: "With all aircraft engines, use full available rated takeoff horsepower for all takeoffs. I cannot think of a single exception. You are usually not being kind to your engine when you use less, and you may very well be mistreating it when you do so."

Exactly! None of us want an engine failure at takeoff, especially below 1000 feet agl, right? That's probably why some people think they are helping the engine by doing a reduced power takeoff, but in fact, they are stressing the engine more by not using full power. .they aren't getting the cooling fuel from the enrichment circuit, and they aren't climbing through that first 1000 feet as quickly as they could. After 1000 to 1500 or so, then you may throttle back. But be aware that most engine failures happen during power changes. .
 
Cooling fuel, carbs and FI ?

My carb 0320 never tops over 310F on full power take off. Yeh I know I have too much cooling air, need to work on that. Do mechanical FI systems have WOT enrichment function ? If not, how does this discussion hold up that Full power is the only way to go. Ring seat pressure may be a valid point, but where does that fit the other 99% of of run time ? Not arguing, just lookin to get smarter :)
 
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.
 
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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.
 
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.
 
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.
 
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.
 
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Full Power

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.
 
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"?
 
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
 
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.
 
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.
 
Yep

WOT...let it run!

Not really the same but I had a C-421 with Continental GTSIO-520's.

Ran it hard all the time after speaking with one of the original engine designers...

Those "troublesome" engine ran 800 hours BEYOND TBO with NO issues...
 
Why 23 inches?

There are several reasons.

One, is KPTK airspace ends at 3500' and we are under KDTW class B at 6000' so I generally don't climb out very high. (2500' to 3000' as I leave the area.

Two, I prefer to pull back the power once I hit 1000' AGL to reduce fuel flow. When local I am usually more interested in duration aloft rather than speed. Depending on what I plan on doing, go somewhere or just cruise around I set 70% or less power, pull the RPM back to 2450 or less and lean out to around 1400 EGT and >400 degrees CHT (so far never an issue). 70% is around 23 inches. I typically will adjust the RPM a little for best speed at whatever manifold I settle on. 2450 seems to be a happy average.

Three, pulling back the power and RPM reduces the noise somewhat which is a neighborly thing to do.

Four, I love the acceleration and climb of full power on take off, but just don't get the same rush once at altitude. That is unless for some reason I want the higher cruise speed/climb rate and don't care about the incremental cost.
 
WOT...let it run!

Not really the same but I had a C-421 with Continental GTSIO-520's.

Ran it hard all the time after speaking with one of the original engine designers...

Those "troublesome" engine ran 800 hours BEYOND TBO with NO issues...

Completely agree. Run them hard, often, and they'll continue to do that.

Leok, throttling back for slow flight, or local cruise/sight seeing/joy of flying flight is understandable, but that would be the only time I'd agree.

If you're taking off to go somewhere, running at WOT to altitude, with proper mixture management, will generally be an incremental reduction in cost. Not only is the throttle volumetric flow more efficient, the higher MP pressure will result in a higher cylinder pressure leading to a more efficient combustion. It also reduces the time to climb and getting to cruise power/speed faster. It's a higher fuel burn in the climb, but with less time in the climb, you'll be at cruising altitude with a lower cost per mile sooner, reducing block-block costs - and time. You can pull back the RPM if you want, but leave the throttle full open.

Not directly a take-off power setting, but another consideration is your Carson Speed, which is the most efficient speed for the airframe based on 32% increase over best L/D speed, generally best glide which for the -10, ~ 85KIAS, making the Carson Speed about 112KIAS, which is why 110-120KIAS climb speed is fairly efficient.

Noise is a non-linear squared function, so if you're concerned about noise at lower altitudes, then getting up high and away from the ground faster makes more sense to reduce your noise the fastest, in addition to changing headings away from population as soon as practicable. Once at cruise: WOT, RPM to suit desired power/speed, and the adjust mixture appropriately. If that's still too fast for your taste, pull back the RPM and readjust mixture, but leave WOT.

If you want to reduce RPM, ok, but just realize the higher the RPM, the higher the horsepower, and most folks fly airplanes to go places, generally fast (a function of "total performance") - and more horsepower will produce more speed. Whatever you do there, just leave your throttle full open and you may find not only better performance, but overall efficiency too.
 
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