Reduced power Take Offs?

[Sig600]

Originally Posted by rvmills

Still having fun here Many are pretty much saying the same thing in reply?we're just giving the OPs question the respect to say why we think so, and apparently fueling a little debate and popcorn enjoyment. Heck, its finally snowing in Reno, and now I gotta wait till the roads are clear so I can drive to the hangar to work on a few new gauges that will tell me just how I can tweak the motor for even more full power on takeoff!

LMAO on the reduced power landings and taxi! Well-played gents!

Ernst, just remember, it's not a flyby?its a low approach!

And reduced power taxi?foreign concept, at least where I work!

Cheers,
Bob

Phhhsh! I have a mound of snow 4' high on either side of my drive way from all the shoveling, get to it!

[rvmills]

Originally Posted by Sig600

Phhhsh! I have a mound of snow 4' high on either side of my drive way from all the shoveling, get to it!

Shoveling done…for momma here and the widow next door (earning my keep…and the long leash! )

4'…now that is when you need to do a full power taxi!

By the way, I know I need to promote you here on VAF…not an L-T…but a LCDR! Have you installed the head-hinges yet?

Originally Posted by 170 driver

I don't usually use full power until I am off the ground and climbing, makes for an easier aborted takeoff and uses a lot less rudder force on my leg and on the rudder. Climb out is at max power. Maybe my reasoning is wrong, but this is what works for me on my taildragger.

Warbirds with monster motors use less than full power for takeoff too…keeps from reversing the direction of takeoff during the roll! I'd love the have that problem! Or a 170…very nice!

Cheers,
Bob

[Red Five]

Originally Posted by Mel

I know it probably uses more fuel, but it makes up by making the brake pads last longer.

[Nihon_Ni]

I fly with the local CAF squadron, and we had a similar discussion about reduced power takeoffs with a R-1340 engine. Here's what we found in the T-6G Flight Handbook. (I highlighted the relevant paragraphs.)

[BillL]

Originally Posted by Red Five

Well, that is one way to clean out the hangar!


Military power - all the engines referred to here supercharged/turbocharged/turbocompounded or some combination. Also they are designed for high altitude, which means the turbo machinery and matches provide much more boost at ground levels than at altitude. It is easy to over boost even with 130 octane. We (mostly) are using normally aspirated engines, so much of the discussion does not apply.

Even for our NA engines, it takes about 10 min (to 15min) to thermally saturate at steady state. 5 min on TO would still allow the temperatures of pistons/top ring grooves and barrel at top ring positions to be in range and not at peaks. I think time to 1000'agl is easily within 1.0 min and should have little effect on the deleterious results of sustained steady state operation at high power/temperatures. Like - top ring groove coking, oil plating on wrist pin, marginal oil film at top ring turnaround, lowered piston fatigue strength due to elevated temps, and higher oil to bearing temperatures, detonation, and more.
Just my opinion, though.

Sorry for the diversion - continue while I get more popcorn.

[rjbob]

Originally Posted by Red Five

What y'all don't realize is that this Maule isn't taking off...the photo shows it backing into the hangar (with reduced power).

[plehrke]

Originally Posted by rjbob

What y'all don't realize is that this Maule isn't taking off...the photo shows it backing into the hangar (with reduced power).

I could not tell from the palm trees that there was a 5 knot head wind.

[6 Gun]

Been in that hangar at Maule believe me my Champ would have been airborne coming out the door the hangar must have been 400' deep most Rv's loaded light would also.
Bob

[skylor]

Originally Posted by 170 driver

I don't usually use full power until I am off the ground and climbing, makes for an easier aborted takeoff and uses a lot less rudder force on my leg and on the rudder. Climb out is at max power. Maybe my reasoning is wrong, but this is what works for me on my taildragger.

The quote from the T-6 manual that stands out to me is this:

In addition to the engine wear factor, a takeoff at reduced power is comparable to starting with approximately one third of the runway behind the airplane. Therefore full power should always be used on all take-offs.

This makes me think of:

Things which do you no good in aviation: Altitude above you. Runway behind you. Fuel in the truck. A navigator. Half a second ago.
Approach plates in the car. The airspeed you don't have.

Skylor
RV-8

[Raymo]

Originally Posted by claycookiemonster

1. "...reduced power take offs burn more fuel..." Really? 'Splain that to me.

2. "...reduced power is harder on the engine than full power..." So, if reduced power take offs are hard, is idle murder? As I've said before, I'm willing and able to learn, but this doesn't pass the reasonableness check yet.

My opinion on the two above:

1. Getting to altitude more quickly with full power - then reducing throttle and leaning the mixture might actually burn less fuel versus reducing throttle throughout the take-off and climb, which would take longer (lots of variables here).

2. There is a valve (forget its name) that is opened only at full throttle on carburated engines that sends more fuel to the cylinders, thus increasing the cooling. This, of course, also varies with density altitude.

If engine wear is the concern, starting and all operation below 180 degrees temperature are the enemy. Once the engine is up to temp, engine wear is at its lowest.

As mentioned by others, any comparison to turbine engines is impossible. Their limits are expressed by turbine inlet temperature (TIT) and max torque.