Question about Throttle Response

[vololiberista]

Thanks LG! Playing with numbers last night I came up with 82.6 inHg for standard ISA. I extrapolated information I have for the Conways on 707's and uprated the numbers!! Perhaps that's a little high.
vololiberista

[nickwilcock]

Flight Idling and Slam Acceleration checks were flown on Flight Tests as follows:

At FL50 and 170 KIAS with airframe and engine anti-icing off, each engine was set to idle and slam accelerated in turn.

Flight idle should be 58-64% HP RPM. Once stable, the throttle was move from idle to max in less than 1 sec. The time from idle to 95% HP RPM had to be 4.5-6 sec.

Normally one would never be so tough on the engines as to slam them in such a way. But I never had one which failed to meet the required limits!

[vololiberista]

Flight Idling and Slam Acceleration checks were flown on Flight Tests as follows:

At FL50 and 170 KIAS with airframe and engine anti-icing off, each engine was set to idle and slam accelerated in turn.

Flight idle should be 58-64% HP RPM. Once stable, the throttle was move from idle to max in less than 1 sec. The time from idle to 95% HP RPM had to be 4.5-6 sec.

Normally one would never be so tough on the engines as to slam them in such a way. But I never had one which failed to meet the required limits!

Thanks for that. I've checked my numbers and I'm getting from 5.2 to 5.4 seconds

[Laurieg]

Nicks figures pretty much match ours on the ground. Looking at the graph most occasions the calculated accel times are generally in those times. We add 1.5secs when on detuners due to the back pressure they cause which slow the times down. Also, our slams are calculated from a stable idle of 57 - 58 NH to max, (recorded during take-off checks), minus 1.5%

[zaffie 03]

Just to set a scene, all the K4 were equipped with engines with various differing hours on them, which added to the complications when it came to 'engine runs'.

Many events on the running bay ensued, a couple do stick firmly in my mind:

On one occasion whist #2 was at full power a fuel flow pipe decided that it would give way in a spectacular manner. I was stood with the rest of the ground crew 'eye balling' events from a safe distance (MLG area) when all hell let loose. What appeared visually was a cloud of fuel from under #2 as the doors were wide open, which almost immediatley was injested by the rolling back #2, but also into #1 which was on idle. Trumpeton who were sat in their fire truck all of a sudden got very motive.
Investigation after the event revealed a very shoddy welded repair of a pipe supplied as part of the refurb kit.

Slam accells always attracted my attention if only to witness the shear amount of movement of the nacells when going from idle to full power. . . .

As always our ground engineers conducted the engine runs under all conditions as they had done since Noah was loading the ark, well Concorde, F1-11's and all of the K2&3's plus the corporated HS125 and BAC 1-11.
Settings were always carfully carried out to ensure Slam's met the higher end of the timescale, plus there was no agressive advancment of the throttles. . . . .
That was fine, however our flight test crew decided to visit proceedings one day and insisted on reconducting the test. Times needed to be reduced incrementley by adjusment of the FCU to meet the lower end of the timescale from idle to full power.
One final attempt was made on acheiving the target, this time with a less than sympathetic advancement of the throttle lever. As the engine accelarated it chose to respond in disgust to such brutle treatment by conducting a series of repeated surges . . . . ground crew, flight deck personnel and even a few of the wire pullers located in the cabin several hundered feet away thought World war three had started.

Zaffie 03