Classic British Flight Sim

Morning,

I have been flying the Trident and 1-11 extensively over the past few years, and have always used the method of 100% on the Thrust Index gauges, EGT out of the Red (600c) as my power setting for takeoff.

Now, I was reading somewhere (it escapes me exactly where) that there were actually two power settings used for takeoff - Max Power and a slightly derated setting - possibly called 511 Power? I assume this was simply to reduce TGT and maintenance costs, and that it was calculated from tables in the performance manuals.

Being the OC type, I like to fly as realistically as I can (within the obvious confines of the sim), and would like to try and find out a bit more about this procedure. Unfortunately, the Royal Archives are a bit inconvenient to visit to consult the real world Trident documentation so I was wondering if there was a rule of thumb I could use to obtain a derate - assuming that it was simply a reduction applied to the Maximum Power Thrust Index for the given ambient conditions? Or was it a reduction in the allowable TGT for takeoff? Conversely, where Water Injection was used in limiting conditions can the Thrust Index be wound forward by an equivalent amount to still produce 100% Thrust and remain within the TGT limit?

One more thing - I have always used 11900rpm as the climb power setting for both Trident and 1-11; is this correct or would 11800rpm be more suitable? I know it's not a huge difference but if you are going to do it - then do it right I say!

Cheers for any help you guys can offer.

Tom

There are Top Temp I think its called that turned on give the max continuous power without over heating the engines as you would on full thrust if you don't thorottle back out of the red ASAP.

On the One Eleven they at the rear top of the central pedistal...accessable on VC only AFAIR.

Don't know about the Trident as I've not flown it much.

It's been such a long time since I was involved with the 0ne Eleven that I don't recall any derated take-off procedure, however if there was one I would imagine that it would give a lower Thrust Setting Index (TSI) from performance charts and you would aim for 100% of that lower TSI setting. For example on a normal take off if you had 150 in the TSI window, 100% on the gauge gives you 100% of 150 so if you reduced this to say 140 it would give you 100% of 140 giving you your derated take off. I don't know any rules of thumb for this, it would have come from the performance manual.

De-min water was normally used to restore power at hot and/or high airfields, e.g, Spain in summer. Normal take-off was 350kg of water so the elephant trap was if it gave you a 250kg increase in RTOW you had a net loss of 100kg of fue/payload available. Therefore normally used at near max RTOW and where it gave a RTOW increase greater than the amount of water used. The water is included in the take-off weight. I can't remember if the use of water affected the TSI setting, but it's function was to cool the air going into the combustion chambers so I would imagine the increased thrust came from the same limiting TGT giving more thrust than if no water used.

As to tanking the water to use on the return leg, on legs over a certain leg, it was a no-no as it froze in the tanks. I think this was about 1.5 hours. We used to position 50kg barrels of water to the usual airports where it would be used, for example, in places like Malaga and Palma we would regularly have a stock of about 30-40 barrels down there. There was an electric pump on the aircraft, if servicable, but mainly loaded by the first officer with a wobble pump on the turnround.

N

511 power?? Works for me!!

For the 1-11, I click on the Thrust Index gauge and it sets itself, hopefully for the correct setting. Then brakes on and increase thrust until the temperature warning lights come on then back off until they go out, then brakes off. I normally put water injection on if OAT is more than 25deg C.
Having said that, when taking off from hot and high airfields the engines need a bit of care and attention. I've had the high temp lights come on just after takeoff and need to throttle back with a climb rate of 100-200fpm!

CH

My recollection of Spey limitations now goes back too long to be accurate,( and stemmed from discussions with RR people rather than first hand experience ) but I have a vague recollection that for the 1-11 Rolls Royce had a 5 minute limitation rather than an instant one ( except on startup which was the critical case ) and you could firewall the levers for up to 5 minutes without harm . Whether the Trident was the same I don't know, but perhaps Peter may comment

I can concur with the hot and high situation.
I flew out of Windhoek in Namibia and had to skim the ground almost to build up some speed before I could climb as even with water injection on I wasn't getting much from the engines.

Paul