Many airliners with underslung engines, when loaded with an aft C of G will tip on their tails when more than a varying % of thrust is applied with brakes applied.
Dan wrote:
My own steed lifts its tail (full rear stick) starting with 2‘300 rpm, so the WOT checks are done whilst on the take-off run… T&Ps good = immediate reduction from whatever MP/2’700 to a standard 23/23, or 24/24
@Dan the RPM reduction is for noise abatement or is there any other reason? I would reduce the MP after lift off but keep RPM till on pattern altitude.
@RV14, mainly for noise. And efficiency as I usually start to lean right at that time too.
We have 11 RVs based on my field, and I guess 12 different take-off techniques 
Most of the guys/gal (yes, we have one, RV-14A builder/pilot 
) fly on their own, gun the power, climb at Vx, and before they know it, are at pattern altitude. In the middle of the upwind leg…
My steed is pretty light (489kg) and I usually take-off with reduced power/rpm, as mentioned 24/24 being the norm. No need to stress the engine out, and easily airborne in less than 200m. We have a 690m long runway, and no major obstacles directly adjacent. I then love to keep her low whilst building speed, and resume my climb when on 100-110 KIAS.
We had a few talks with my friends regarding an eventual engine failure… different techniques with their pros and cons. And preferences. I’d prefer a failure to happen at Vy (85 in my case) or more, with a positive energy gradient, than having one happen hanging on the prop at a steep angle on Vx.
No doubt one of the better subject for hangar flying
Shanwick wrote:
Many airliners with underslung engines, when loaded with an aft C of G will tip on their tails when more than a varying % of thrust is applied with brakes applied.
The SE210 Caravelle was notorious to do that when applying reverse thrust with aft CG. You needed approximately 1 t ballast in the forward hold to fly it empty, particularly the 10B model with the APU. The 10R was better in that regard.
It also had a stick in the back which had to be mounted immediately after engine shut down by the aft Flight Attendant. My wife has considerable experience mounting that thing. Once we lost the stick during a towing to another parking position with me occupying the FD. After I had shut the airplane down and walked back to release the aft air stair and disembark, once I reached the aft galley I could feel the airplane start to settle on it’s tail. I immediately ran back forward again, and it came down onto it’s nosewheel. I then (this was before mobile phones and also 30 kgs before with regards of my own weight) had to restart the APU to get the radio going to call the Tower and the handling agent to get back out, look for the bequille and put it back, before I could get out of the plane.
Silvaire wrote:
You also BTW don’t want the brakes to be too powerful, the ideal is just enough to hold it for run up without great pedal pressure.
Our brakes are certainly powerful enough (double pot Clevelands) but with the heel brakes you don’t have any mechanical advantage over the system (essentially you’re standing on the master cylinder when applying them) so you would have to be extremely “ham footed” to put the plane on its nose (it would require a significant leg effort). Also the Auster is one tailwheel type that’s less likely to lift the tail if you’ve got the stick all the way back. But even so, when we had to do some full power tests back in 2020 after replacing some time expired fuel system parts (and also rebuildiung the brake master cylinders and replacing the pipe work) this was not done static, rather we ran down the runway at full power.
High speed taxi runs must be treated with a bit of caution in a tailwheel aircraft, as the steering characteristics change quite a bit when you take the power away and especially on a hard surfaced runway, if you don’t prepare you can end up with a short sharp trip to groundloop city! You can also be running significantly faster than takeoff speed in very short order in a light tailwheel aircraft with a decent amount of power as it’s easy to keep the angle of attack down while rolling on the mains without a nosewheel getting in the way, so it’s important to recognise the potential hazards of this (e.g. prematurely bringing the stick back). You kind of treat it like a wheel landing when you take the power out.
