unrealistic flight behavior

[JamieKugelmann]

Hello

I have been playing around with the L-049 a bit, and I found a weird bug.
When in cruise, I turned the mixture to idle-cutoff on all four engines. The RPM remained high since the props were windmilling, but the flight controls suddenly didn't work! The plane was completely uncontrollable with the mixture in the cutoff position. As soon as I placed the mixture to auto lean, the flight controls began working again.

[mallcott]

Booster pumps for the hydraulic assist on the controls need engine power, not simply rotating props.

[JamieKugelmann]

Booster pumps for the hydraulic assist on the controls need engine power, not simply rotating props.

I'm not sure how that works, since everything in the engine is turning as one.

[AviationAtWar]

If the crankshaft is turning then the hydraulic pump is turning.

[JamieKugelmann]

If the crankshaft is turning then the hydraulic pump is turning.

Precisely.

[CAPFlyer]

What did the hydraulic pressure gauges say?

[cflord]

If the prop is rotating, the engine is rotating, and if the engine is rotating the hydraulic is rotating and should be putting out hydraulic pressure based on how fast the engine and prop are rotating. They are all directly interconnected with each other. Like CAP asked; what was your hydraulic pressure gauge reading? If the engine/prop is rotating at a higher RPM the hydraulic pressure may be near normal. If the engine/prop is rotating at a lower RPM, then the hydraulic pressure may be lower than normal or non-existent depending on just how low the RPM is. The hydraulic pump is connected to the accessory drive on the back of the engine. The RPM of a windmilling engine (not running) is directly dependent on airspeed. Remember, a windmilling engine (not running) is nothing but pure aerodynamic drag and should be "Feathered", unless a greater emergency exists.

Keep the shiny side up and the dirty side down!

Ret SMSgt Cliff Lord - C-130 Flight Engineer & Mechanic

[Tobus75]

I'd be intersted in your hydraulic pressure gauge readings too.
And what would be the result on controls and that gauge when also feathering the props.

[alan CXA651]

Hi.
Remember , if you loose hyd pressure , the control boosters MUST BE DISENGAUGED , to go to manual controls , they will be heavy and only move about half the distance on the peddles/column/wheel , but you can then at least control the aircraft to some degree.
regards alan.

[WB_FlashOver]

The plane was completely uncontrollable with the mixture in the cutoff position. As soon as I placed the mixture to auto lean, the flight controls began working again.

The engines will not start with windmill effect in auto-lean. They will however start with windmill effect in auto-rich. So, I think his point is that why do they work in auto-lean (engines not running) and not work in cut-off (engines not running). I'm curious about hydraulic pressures too but it may be that there is something in the code that says "if levers are in cut-off then hydraulic no worky".

Roger

[JamieKugelmann]

Sorry, I have just tested it again.
Hydraulic pressure in the green as suspected.
Windmill engine start to auto rich allows movement of flight controls once engines fire. Once they are not firing, but windmilling at max rpm, the flight controls are not able to be moved.

[WB_FlashOver]

Well that changes things a bit. While attempting to learn and understand the fuel transfer system I ended up with engine 2 windmilling on me. I was only getting 500 RPM under windmill effect. I did not look at hydraulic pressure, however I would really doubt that 500 RPM is enough to produce the required pressure/volume for flight controls.

[LostSoul]

To me it seems that the Hydraulic System is not thoroughly implemented. Look at the Hydraulic Pumps Warnings Lights when the engins are on low RPM. They are all illuminated. Nevertheless both Hydraulic Gauges read normal pressure.

[SISU]

To me it seems that the Hydraulic System is not thoroughly implemented. Look at the Hydraulic Pumps Warnings Lights when the engins are on low RPM. They are all illuminated. Nevertheless both Hydraulic Gauges read normal pressure.

Seems to be true, I've made an on-ground test yesterday:
1) Started all engines, idling at 1000RPM, hydraulic pump warning lights on -> hydraulic pressure gauge reading at around 1700 lb/sq in. -> flaps & flight controls moving normally
2) Shut-off all 4 hydraulic valve switches, hydraulic pump warning lights on -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally (shouldn't they stop moving with boosters on and no hyd press?) but flaps won't move
3) Turned on 1 hydraulic valve switch -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally and flaps moving veeeery slowly
4) Turned on 1 more hydraulic valve Switch (now 2 out of 4) -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally and flaps moving slowly (about half speed as when all hyd pumps are turned on).

Am I misinterpreting something, or is it possible that there are few bugs within the hydraulic system? And by the way, great work on the connie, I love it!

[Hobart Escin]

To me it seems that the Hydraulic System is not thoroughly implemented. Look at the Hydraulic Pumps Warnings Lights when the engins are on low RPM. They are all illuminated. Nevertheless both Hydraulic Gauges read normal pressure.

Seems to be true, I've made an on-ground test yesterday:
1) Started all engines, idling at 1000RPM, hydraulic pump warning lights on -> hydraulic pressure gauge reading at around 1700 lb/sq in. -> flaps & flight controls moving normally
2) Shut-off all 4 hydraulic valve switches, hydraulic pump warning lights on -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally (shouldn't they stop moving with boosters on and no hyd press?) but flaps won't move
3) Turned on 1 hydraulic valve switch -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally and flaps moving veeeery slowly
4) Turned on 1 more hydraulic valve Switch (now 2 out of 4) -> hydraulic pressure gauge still reading at around 1700 lb/sq in. -> flight controls moving normally and flaps moving slowly (about half speed as when all hyd pumps are turned on).

Am I misinterpreting something, or is it possible that there are few bugs within the hydraulic system? And by the way, great work on the connie, I love it!

If in fact A2A have indeed modeled a simplified hydraulics model on the Constellation as it appears they have, all I can say that is I'm both surprised and disappointed. A2A are a very talented group of individuals with high personal standards and 'cutting corners' like this is beneath them in my opinion.