Engine Failures

[DuntoiRab 0]

This is strange. Three times today, 2x in the DM BAC1-11 and 1x in the DM HS Trident 3, I experienced total engine failure.

 

Upon checking the failure tab on each occassion the red checks were in the failed boxes e1 2 and 3 for the Tri jet, 1 and 2 for the Speys.

 

Now, never, ever in my 15 plus years of simming have I set failures. I am not interested in those scenarios.

 

What or how could failures be set whitout my knowledge? I haven't a clue and would appreciate any ideas.

 

FYI, no new a/c have been installed, just a coupleof freeware sceneries I need for our current classic BA a/c tour of Europe.

 

TIA

[ckyliu 1,749]

Ensure you have reset the failures properly. Does DM's stuff simulate engine failures due to overstress (i.e. prolonged exceeding of EGT limits).

[vololiberista 205]

As far as I can tell the BAC 1-11 uses A vars for engine fires so they would be governed by the sim settings.

[DuntoiRab 0]

I know what it was now. Both models have an engine top temp switch. It prevents full throttle movement to protect against over cooking the engines.

 

Because of the slow sluggish climb performance I had switched ETT of and firewalled the throttles.

 

Now I know the models have hot engine shuit downmodeledin them.

Kind of cool, you learnstuff all the time.

[ckyliu 1,749]

The Trident was known for rubbish climb performance, they early 1Cs were nicknamed "gripper" and it was said they only took off because of the curvature of the Earth! The 2E and 3B were better, just make sure you're not too heavily loaded and don't forget you can always use the 3B's 4th engine to launch you off the deck (you're on your own after that because it shuts down by 500 ft)

 

The BAC 1-11 you shouldn't have climb issues with generally, although if the ambient temperature is high you can use the water injection for a "wet takeoff". Though I'm not sure if BA's  510EDs had this facility.

[vololiberista 205]

The top temperature controls only diverted hot air into the airframe anti-ice system. The 1-11 engines were prone to overheating and had water injection. I'll have to have a look at DMs coding but I'm not sure if he actually coded the top temperature controls to also reduce the throttle. He has a P7 gauge for the pressure at the back of the turbines but it's a fake.

   The hot air is a by product of high ambient temperatures which cause the engines to overspool. That is not controlled by the top temperature control switches. That is good old fashioned manual throttle control.

   DM also used default MS airfile tables for all his models hence the surge during start-up. P7 is extremely difficult to calculate as far as the sim goes. First you have to code the maximum values allowed at any airfield elevation at any altitude. Then you have to code for how the gauges actually behave for any given temperature and pressure. If the engines did not reach the maximum value allowed then the take-off was aborted. A fairly rare event as far as the RR Conways on the VC10's were concerned.

    I did a lot of work on DMs VC10 panel regarding the engines. The airfiles were completely re-written with new throttle relationships and thrust curves etc. It took a very long time to calculate the correct polynomial curves for P7 and to calculate when full throttle was not to be used. The 10 had either full throttle or factored power. Factored power was a rough calculation as to how far to advance the throttle on take-off. And this was placarded in front of the pilots. 100% 96% and 93% TLA or "Throttle Lever Angle" There were no markings on the pilots throttles or the FE's. It was a guestimate attained by experience.

  The RR Conways do have a fuel limiter that cuts in at about 105%n2 but that has proven rather difficult to model as in the sim fuel is directly related to the throttle position. The consequence is that when taking-off from Kuwait for example the crew needs to more than heed the engine limitations shedule to prevent the engines overspooling and breaking up. Or causing an emergency shut-down to prevent further damage. Not something you want to happen just after take-off!

   The VC10 panel update now has full callouts including "Power checked" when the thrust meets the correct P7. N2 varies according to throttle position and ambient temperature and pressure.

   Although the VC10 itself was designed for hot and high airfields the engines don't like hot air at the front. This is unfortunately a problem with all jet engines.