Increasing engine power in a helicopter

[SASless]

Having been awkeneded from a sound sleep by a Labrador Retriever who either has a smaller bladder than mine or knows when I am sleeping the sleep of the dead....I feel compelled to give my offering while I await the Princess to come back so we can all return to our slumbers.

The answer should be simple but it as in most things helicopter a bit. harder to lay out.

Assuming it is a straight forward increase in engine horsepower uptick such as when the Huey went from its first engine to later models....usually the aircraft was limited to the same certified weights, and torque limits of the original aircraft or as in the case of the Chinook in the A Model that saw stronger engines. installed.....the only improvement was in the retention of performance at the same structural limits.

In the case of later improvements of the basic aircraft that came along with upgraded engines such as the latest models of the Huey being flown by the USMC the new aircraft is a completely different airframe as compared to the older versions.

As it is 0230 in the middle of my night....this input was provided you due to Miss Reagan's wet nose summoning me to temporary duty without pay as the Door Man of the Goose Bay Tea House.

Now back to bed it is for me and that damn dog and whichever Cat it was that was snoring away at the foot of the bed.....probably the three legged J.R. Mewing.


Now that I am awake....with coffee number one in hand.....I might clarify what I posted earlier.

In the case of the CH-47A....we went from Lycoming T-55 L5 engines to L7's, and finally L7-C engines with no other changes to the aircraft.

With 7C engines the old girls would do everything we asked of them.

The 7C had been designed for the CH-47B and early model CH-47C's and later we went to L-11 engines for the C Model.

The B model had some minor changes...square tail being the most important as it greatly improved yaw stability and different rotor blades than the A model.

The C Model with L11 engines was a real horse....full of fuel at a hover....shutting down one engine could be done without any real difference in the handling of the aircraft....other than a split in Torque needles and the engine gages showing the shutdown and at most just one or two Rotor RPM decrease.....no other signs of just being on one engine.