Power Checks

[Kicking Skids]

I am looking for the methods you use to do power checks on turbine and piston engine helicopters. Any tips, rules of thumb or advice might be useful to anyone doing confined area or high altitude operations.

[Vance]

I am looking for the methods you use to do power checks on turbine and piston engine helicopters. Any tips, rules of thumb or advice might be useful to anyone doing confined area or high altitude operations.

I have found value in the Pilot Operating Handbook.

Most of them I have seen have very specific performance parameters.

In my opinion, with a piston engine measuring the leak down and inspecting the bore with a bore scope is useful during the annual. At oil change intervals cutting open the filter element and inspecting for metal as well as oil analysis are good ways to stay on top of your piston engine’s condition.

A careful pre-flight inspection keeps track of the many other flight critical components.

I have very little turbine experience so I will leave that to someone else.

Thank you, Vance

[RotorTom]

Hover, then check instruments. It's that simple.

[RotorTom]

Oh, also what Vance said ... cause it gives pretty accurate predictions.

[Kicking Skids]

Thanks for the advice guys.
I agree that the POH normally provides this information but some manufacturers do not provide the performance figures.

Noting the power used in the hover is also very useful but if you subsequently plan to land at a different density altitude, then these values are not relevant - if you see what I mean.

[brett s]

It's definitely still relevant, you just need to also know power available at that different density altitude.

[bryancobb]

The REAL valuable information you need before takeoff is is 1) What is "Hover Power" today, and right now, this moment. 2) How much power ABOVE HOVER POWER can you make right now at this moment.

On my Brantly, I hovered into the wind, and noted hover power. Then I momentarily rolled on full throtle and made a mental note of how much EXTRA TWIST I had of the throttle, and noted Max manifold pressure available.

If I had very little EXTRA TWIST, then I'd limit my flying to IGE maneuvers and conservative TO/LDG profiles.

On turbines, over time, the compressor blades get a film of particle buildup on them that has the same effect as compression loss in a piston engine. Some form of H.I.T. check will give the pilot a way of evaluating how bad this problem is. I have never OWNED a turbine so I don't know but I'd guess the mfg has a procedure for this. We always had to do this on military helicopters on the first flight of the day and log the results in the maintenance records.

[StanFoster]

My helicopter does not have a torque gauge on , poor mans turbine, but I did add a microswitch that tells me if I am asking the turbine to deliver full power. I could come up with a light that I could set to come on at less than full power, but in all reality, I am at 750 foot altitude, and i have considerable excess horsepower. I flew the other day at 98 degrees, full fuel and it had all kinds of reserve power. I still have a blank light in my dash that I could activate with another microswitch showing me when my turbine is at say 90 %. I could set it on a worst case scenario such as the other day at gross and 98 degrees. Stan

[hillberg]

A power "HIT" check is not a one time deal- It is the exhaust temps,Ng rpm,Torque adjusted for DA. and the check is compairing the health of the engine as it was ran to a base line in a test cell. What you are looking for is a deviation to the base line-As the time goes on the performance will degrade from normal use. With the T-62 all you can do is get it light on the skids and note the collective position and see the Temp and adjust for DA. Repete before each flt and make a note. It would be nice to have a torque guage, Could you mount a digital (Torque wrench parts) on a support arm?

[ferranrosello]

The best thing I can say is check the fly manual. Any way there are some rules of thumb, but you need to know your machine pretty well.

I use to fly over the intended landing area in a horizontal path at 100'and at the minimum safety speed (it depends on the aircraft, but it is the lowest airspeed at which you have effective translattional lift). Then you need to know how much more power is needed to hover your helicopter (I use normally about 20%).

If you have this power avaiable over the required power for the 100' low flight, then you have enough power to hover the helicopter in ground effect.

Be aware that if you want to perform a landing in a confined spot, having power in ground effect is not enough...

Ferran