BAC 1-11 temperature limiter and engine performance...

Macs · Post by **Macs** » 12 Oct 2006, 01:20

Hi,
I guess this one goes to David M. First, again. congratulations on another great update! Second, I lost both engines on a takeoff from a relatively short runway (6500 ft) but near sea level a few minutes ago. The weather was hot ~32 deg C, and of course the EGT's went into the red when 100% power was achieved.
I did use the water injection system, but the temperature just did not keep in check and I did not use the temperature limiter as it would have been impossible to reach V1 in time. Being a new update, I was not aware of the consequences

, but anyway, I did loose both (No. 2 being the first to go).
So I guess my question is: Are there charts we can use to know under what conditons of temperature and runway length we can takeoff safely? Even at full 100% and flaps at 8 degrees, I barely made it (9500 kg of fuel) to Vr before the end of the runway (the plane lost the engines a few seconds after rotation).

Thanks in advance for your help,
regards,

Macs

Chris Trott · Post by **Chris Trott** » 12 Oct 2006, 02:47

Well, rule number 1 is - use the temp limiters. If you don't think you'll make it - dump passengers. If you still don't think you'll make it - dump fuel and make a tech stop. If you can't dump enough people or fuel to - a) make a profit *or* b) make it to an airport with sufficient runway length, then wait until it's colder.

I don't know of any runway safety charts on my system, but 6500 is pretty short for the kind of fuel load you were looking at.

Macs · Post by **Macs** » 12 Oct 2006, 04:13

Chris Trott wrote:Well, rule number 1 is - use the temp limiters. If you don't think you'll make it - dump passengers. If you still don't think you'll make it - dump fuel and make a tech stop. If you can't dump enough people or fuel to - a) make a profit *or* b) make it to an airport with sufficient runway length, then wait until it's colder.

I don't know of any runway safety charts on my system, but 6500 is pretty short for the kind of fuel load you were looking at.

What is "sufficient" runway length?
I guess I forgot to add I was using flaps 5...

regards,
Macs

DispatchDragon · Post by **DispatchDragon** » 12 Oct 2006, 04:42

And there lies the rub Macs - short runway more flap - as Chris says use the limiters and fly V2 +10 on reduced power and allow the aircraft accelerate at a "reasonable rate of climb" (in some cases terrain allowing
less than 1000 fpm) You didnt mention which model 1-11 - I have been running the 400 series out of fairly short runways - 6500 foot isnt that short for the 1-11 although 32C is bloody hot - DanAir operated 400s from Luton when it was only 6700 foot and they performed much better than the 500s - and they operated at MTOW until about 29/30C then
started becoming restrictive. My suggestion is use balanced power, 15 flap and fly the Vspeeds given and unless you have rising terrain - climb slowly.

Cheers

Leif

Post by **MALTBY D** » 12 Oct 2006, 12:38

I'd forgot about the built in catastrophic engine failures!
That was an experiment & was meant to be reviewed before release.
Ah well, it serves you right for abusing RR engines.

I think it allows you about 90 secs of continuous engine over heat. Real ones could probably take more than that, but you get away with far too much else in FS.

The water injection effectively lowers the temperature a few degrees. It's not a massive boost, but will allow an extra few hundred pounds of thrust for the same EGT.

Good advice has been given above, which I can't really add to at all.
Sadly I don't have any charts for required takeoff run, but you can't go long distance from short runways.

Another thing I forgot was to make V1 adjustable on the little card. It always takes a default of Vr-5, which would be way too late on your takeoff run.

DM

bigred1970 · Post by **bigred1970** » 12 Oct 2006, 13:04

this is similar to my experence. My home apt, (lousiville standiford int, KSDF) longest runway is 10000 feet and when it was >30c the 500 just barely made it into the air by the end of it without going into the red (much >.> ). but now with temps of 15-20c it makes it into the air easly. it is not a fast climbing plane though even at the lower temps, I usually manage 1000fpm at 250kt untill 10000 and then arount 500 fps at 300knots from there till crusing alt,

Post by **MALTBY D** » 12 Oct 2006, 13:40

The weight makes a lot of difference to takoff & climb performance.

I've been flying the 1-11s with the CBFS va & it's been quite a surprise how light they usually are for takeoff.
I'm usually doing 500-800nm trips & performance is very good. It's quite a slow cruiser though.
On my typical routes, it never needs any fuel in the centre tank & it's quite rare for the wings to be more than half full. It goes all the better for it. :dance:

DM

Chris Trott · Post by **Chris Trott** » 12 Oct 2006, 15:10

Yeah, but you didn't try Manchester-Corfu-Manchester. That's stretching the legs of the 400. Plenty of runway, but had to weight-limit the passengers, so while in FlyNET we made full revenue, we really didn't fly everyone.

Post by **MALTBY D** » 12 Oct 2006, 16:27

Certainly not, that's way too far for me.

Actually, I may have to give that one a try. It may be a bit easier now it's colder up here.

DM

Post by **MALTBY D** » 12 Oct 2006, 19:02

Yes, I was right - way too far for me.
Just did the longest CBFS 1-11 route I could find, EGCC - LGRP, 1670nm.
A full 1-11 500, fuelled to the top & only 500 kg left on landing.
I'll not be doing that again.

Well not after I've flown it all the way back home. :crying:

DM