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FS2004 Is this how it happens in real life?

BaiterOne

BaiterOne

Messages
261
Country
ireland
Hi,

I fly a slightly modified C172 in FS2004, usually very short trips around Ireland at 2000 - 2500', VFR and no flight plan.

Recently, to have a trial of IFR in the flight planner within FS2004 (for a couple of years when I flew a 737 I used FS Commander), I set about organizing a flight from EIWT Weston to EICK Cork. I accepted the height of 4000' which the planner gave me.

I don't normally fly this high because, by the time I would reach it, it would be time to descend.

Anyway up I went and achieved the height 3 or 4 minutes into the flight.

Leaned the mixture at 3000' as directed in loads of manuals.

REX had deduced that the weather had lots of cloud at 4000', thunderstorms way off in the distance and a temperature of -4.1° C (I didn't see any of this outside the house, but I presume REX was right).

Within a short length of time the RPM was reducing, my speed was diminishing rather quickly and my pitch was getting higher. Pushing the throttle up to the limit wouldn't increase the RPM.

I asked ATC for a lower altitude but my request was denied (the brats!).

I watched the scenario unfold until I stalled (25 minutes later), recovered from the stall and then gave up!

I tried the same flight with the same weather in the standard C172 - with exactly the same effect, speed dropped, RPM dropped and pushing the throttle up to the limit wouldn't increase the RPM.

I tried it again with user-defined weather, clear skies and much much warmer - speed stayed on the button, RPM hardly moved - no problems at all.

Could the C172 not fly this cold weather in real life? Was this effect really due to the cold?

What could I have done to make it better?

Thanks

Walter
 
Thanks for the responses.

In my little C172 I have Pitot Heat, which I presume works ( 0 (>K:PITOT_HEAT_TOGGLE) ), and an imaginary Panel Heater, which I know doesn't work :-)

I didn't seem to have any other options.

Walter
 
Walter,
It can happen just like you said.
On 25 Jan 1979, a cold clear windy day, I took a Robin DR400 from Rochester EGTO to do an hours continuation training.
At the time I had about 3600 hours flight time, had just completed my CPL and IRT on PA34. I had about 200 hours prop time and the rest was jets.
Of that prop time less than 10 was with carburetor type piston engines.
I took off and flew South, past Headcorn down to Tenterden where I lived, just sight seeing, head out of the cockpit.
Then I noticed the RPM were dropping as was the speed, so I turned back towards Headcorn.
Very soon I realised I was not going to make it so I picked a reasonable sized field and headed in that direction.
I suddenly thought "carb icing!" and opened the hot air intake control. This must have melted a load of ice because the engine choked and died.
That control was shut very fast. The engine picked up a little and I made an approach to the field. Just before I got there I noticed there was a wire fence right where I had planned to touch down. The last little bit of power came in and was enough to get me over the fence. Nice touchdown on the grass, no need to shut down the engine, it did that itself.

The next few hours were filled with enough comic relief to keep me in jokes for months. The local bobby arrived, thought for a while and asked me for my license. The local volunteer fire brigade turned up and left gleefully to take the rest of the day off (they all worked in a hardware shop) to clean their engine. The owner of the house where I went to call in my situation to the flying club came with me to see the airplane and said "my isn't it small"
The Scottish engineer from the club turned up with the chief pilot, muttering under his breath about "bloody pilots".
Of course there was nothing wrong now, the ice had melted, they took down the offending fence and flew it out.

Yes it can happen and all airplanes bite.
Roy
 
In the C172's aircraft.cfg you have this line..

critical_altitude= 0 //Altitude to which the turbocharger will provide max design manifold

As we are discussing this same effect in our current project, I have learned that what this line means is that you lose around 1" MP per 1,000 feet. And it is actually what should happen. If you set crit alt to 4,000 you would probably see that your engine is delivering constant power. Go ahead and test.
 
The C172 has a ceiling of 13000 ft. At that altitude the engine HP is just over 100 compared to 180 at sea level.
Walter was talking about 4000ft where the HP would be 140, nowhere low enough to explain what happened to him.
It does not have a turbocharger, so there is no critical height.
If you wanted to set a critical height you would also have to change the normal "turbocharged=0" to 1.

I did not realize that the sim does engine icing, but then I do not usually use this type of airplane
Roy
 
Walter,
I thought Weston rang a bell. I lived in Clondalkin as a lad and flew from there a couple of times around 1958-1959 on leave from the RAF.
As I recall there was a nice grass runway and a Land Rover. The Land Rover was used to herd cattle off said runway when someone wanted to land or take off.
The westerly approach had some huge trees just North of the centerline which made for interesting times.
They also had a hangar with about 10 stowed dismantled Tiger Moths. They must have fetched a few bob.
Roy
 
Roy, Weston is now an airport with a stream (admittedly a small stream) of business jets making use of its 3000' asphalt runway and facilities. Loads of learning going on there too - busy spot for touch-and-go's. It is also used as a hub for aircraft participating in airshows around the region.

I go there plane-spotting every so often.

I am glad that you survived your encounter with ice in the Robin DR400.

Personally, I believe that my own reaction to my encounter with ice was safer than pitting myself against fences and hard ground - CTRL+C is a great response to dangerous situations! :-) Probably not too available in real life!

Weston is very bare and basic in FS2004 and FSX, but there is freeware FS2004 scenery which doesn't do too bad a job of depicting the reality.

I fly the freeware RealAirSimuations C172 in FS2004, with a modified cockpit. It is a tweaked version of the MS C172. I can look at the .cfg file but not the .air using AirEd, it appears to be protected in some fashion. I think it may have been after-fitted with a turbocharger.

I may go back to the basic MS C172 as everything is visible there and I can know what I am dealing with, insofar as I ever know what is going on behind the scenes in FS2004.

Anyway, thanks to you and the others for your interest and responses.

Walter
 
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