Learjet 35 v1.2 a few observations

[RobdeVries 28]

Hi there,

 

First of all let me be clear that I love the Lear period. After some familarization flights I think I noticed the following  item/issues:

 

• auxiliary hydraulic pressure pump not operating with engines off. So no hydraulic pressure when initializing AC. 
• The decrease rate of hydraulics is way too fast. Because when pressure is not used (by e.g. parking/brakes or other flight controls the rate of pressure decrease should be very slow). The build up of pressure is way too fast after swtitching the hydraulic pump with engines running and too high value.
• Spoileron reset not working (not even as dummy switch)
• Encode ALT XFER not working (not even dummy switch)
• The aircraft slowly creeps forward while idling (when parking brake not engaged).
• Emergency brake not operating at all.
• Although Anti skid is activated the tyres are locking while braking (outside view)
• NAV/GPS switch has no clicksound
• Alerter NIGHT/DAY switch has no textures.

Nice to notice that the spoileron system is working perfectly!

 

Thanks very much,

Rob de Vries

 

NB this message is also send by email to the developer.

[RobdeVries 28]

Okay got a quick email back from Flysimware:

 

Dear Customer,........1. I only know the 1 switch for the hydraulics and this only works if the engines are running. The speed can't be changed from this type of air file. The PSI level is 1,750 which is what my build sheet had from our tech guy......2. The spoileron reset and ALT XFER are static as we did not create dummy switches for functions that do not work. We mention this in our user manual......3. We are going to work on getting a lower rpm since it's also hard to reduce speed during descents and this is why it moves forward when sitting on the runway. We can't reduce power as it needs the amount we have to fly at 45K.....4. parking brake works perfect, not sure why your having an issue and nobody else has mentioned this......5.Using rudder pedals the brakes only lock with the anti off and do not when on. Are you using rudder pedals for a button? .......6. Yes your right i will add a sound to the nav/gps......7.Yes your right the alerter sw is missing textures. Not sure how this got removed but will fix it.......Thanks!

 

[RobdeVries 28]

Judging from the reply on the items about hydraulics and the emergency brake it seems that there's some confusion. Either on the developers part or on my part... :smile:

 

In the FlightSafety Learjet 30 series pilot trainings manual we can read on page 13-2/13-3:

 

 

Unless there is residual hydraulic system pressure, the auxiliary hydraulic pump must be operated to provide pressure for setting the parking brakes prior to engine start. Placing the HYD PUMP switch in the on (HYD PUMP) position starts the auxiliary pump, assuming both engines are shut down and sys tem pressure is below 1,125 psi As pressure increases, a pressure switch actuates at 1,250 psi to extinguish the amber LOW HYD light on the annunciator panel. (see Annunciator Panel section.) At approximately 1,250 psi, the pressure switch stops the auxiliary pump. The HYD PUMP switch should then be positioned to OFF, where it normally remains unless flap operation is required prior to engine start. The LOW HYD light will illuminate if pressure drops below 1,125 psi. If the HYD PUMP switch is left on, the pressure switch will cycle the pump between 1,125 psi and 1,250 psi.

 

So my guess is that when initiating the LJ35A in the sim and I notice that after switching on BAT 1 the Hydraulic Pressure gauge reads "0"  value I should flip the HYD PUMP switch to  electrically start the auxiliary hydraulic pump  to get at least 1,250 psi pressure to (de)activate the parking brake in order to start the engines. That's not possible right now.

 

Secondly the LOW HYD light should go out at any value equal or greater than 1,250 psi.

After I started the engines the mechanical driven hydraulics pumps take over to provide hydraulic pressure. But when I switch the HYD PUMP switch to the OFF position:

1. the LOW HYD lights comes immediately on, which is incorrect it should some on below 1,125 psi

2. after a few seconds the pressure drops to zero which is incorrect. Pressure should drop very slowly when no hydraulically driven systems are used. 

 

From the manual page 13-4:
 

After starting the first engine, the HYDRAULIC PRESSURE indicator should be checked to verify engine-driven pump operation. Pressure should stabilize at 1,550 ±25 psi, indicating that the engine-driven pump is operating properly.

 

After starting the first engine in the sim the HYDRAULIC PRESSURE indicator gauge shows 2,500 psi

(max psi) which is incorrect.

Also the behaviour of the parking brake after flipping the HYD PUMP switch to the OFF position is incorrect. Although it is correct that hydraulic pressure is declining slowly, the parking brake will loose it's grip after some time and the AC should be able to roll after a while (unless properly chocked). This is not modelled correctly.

 

So my request is that since Flysimware is known for their system fidelity, please model the auxiliary pump function of the HYD PUMP switch while engines (and for that matter mechanically driven pumps are off) are not started.

 

 

Furthermore with regard to the Emergency Brake which is not functioning in the sim LJ35A and which is not a kind of parking brake as suggested in the reply of Flysimware.

 

From the above mentioned manual from page 14-12;

A  pneumatic emergency brake system is used to stop the aircraft if hydraulic pressure is lost. Neither antiskid protection nor differential braking is available during emergency braking.

My request is to correctly model it's function. I guess it could be modelled as kind of parking brake which uses air (so the emergency air bottle gauge should be affected as well)

 

From the manual (14-15):

EMERGENCY BRAKES
Pneumatic emergency brakes are provided for use in the event of normal brake system failure. Antiskid protection, differential braking, and parking brakes are  not available while using the emergency brakes. To apply brakes with the emergency system, the EMER BRAKE handle must be pulled out of its recess (see Figure 14-11) and pressed downward. This meters pressure from the emergency air bottle through four shuttle valves to the brake assemblies in proportion to handle movement. Releasing the handle stops flow from the bottle and allows applied
air pressure to vent overboard, which releases the brakes.

[CW46 101]

" I only know the 1 switch for the hydraulics and this only works if the engines are running".

 

The engines have mechanical hydraulic pumps to provide normal system hydraulic pressure.The switch has nothing to do with output from the engine pumps and should be off if the engines are running.The hydraulic pump switch operates an electric auxiliary pump to provide pressure when the engines are not running. For example to set the parking brake, position flaps on the ground during preflight. In the event of a loss of normal system pressure in flight it can be used to position flaps or provide brake pressure provided there has not been a complete loss of hydraulic fluid. It does not have sufficient output for landing gear, spoiler / spoilerons or TR deployment. It is a small capacity pump which is limited to those actions.The normal in flight hydraulic pressure would be about 1550 psi, the system has a relief setting around 1700 psi to prevent system damage such as over pressure in the hydraulic accumulator.I think the 1750 is just how the gauge was presented, it would not be that high if the relief valve was working as intended.

 

I can not recall the specific ground idle N1 (fan) but I am thinking it was in the low 30% range, if the parking brake was not set the aircraft can roll forward at light weights or on a sloping ramp condition.

[Flysimware 647]

Our first option was to make the HYD switch static. I had trouble making the switch run the hydraulic system. I finally got the coding correct to switch the hydraulic on/off but it only works if the engines are running. And if i use no switch then you only get hydraulic pressure if the engines are running. So the air file for jets are forcing the main hydraulic system to work from the engine state. But there is no auxiliary system i see in the codes.

 

Due to FSX not having an auxiliary system i should have left the switch static. So i am open to ideas since changing the cfg will not create hydraulic pressure when engines are off.

 

For the speed of the hydraulic system it fast when the switch is used and slow when the engines are turned off or on. This is why your seeing a fast response.

 

For the emergency gear it uses emergency air to blow the gear down. And we designed the gear to drop down fast in 1 shot rather than the default pump 22 times.

[RobdeVries 28]

Ok I understand. No coding outside SDK like hydraulics in the A2A offerings.

I'm not speaking of emergency gear but emergency brake. Which id also pneumatically driven and not modelled as far I can see. 

[Flysimware 647]

My solution to this topic is to change the hydraulic cfg to have 1 electric pump. I would then make the HYD switch a dummy switch since once there is battery voltage the "circuit hydraulic on" is always active. So the switch would have no effect on what is supplying the hydraulic source. With this new settings the only way the engines will control the hydraulic flaps and brakes is if they are running or the voltage will allow the electric hydraulic pump to work.

 

According to my manual you can only use this auxiliary pump for 3 minutes and 20 minute intervals so it does not over heat.

 

So again this will not be perfect but you will have control of the flaps and brakes by 2 sources.

 

When testing the original setup i have i noticed when the engines are off the flaps will still move very slowly and work. This is odd as i have never seen this. Not sure why!

 

I also am updating the hydraulic cfg as the mistake was the config using 1,750 PSI. I need to use 875 PSI since there are 2 engines and then the gauge will show the correct output.

[RobdeVries 28]

Great :smile:. Remember the output of the electrically driven aux HYD pump is 1,250 psi...., output of the engine driven HYD pump is: 1,550 psi.

Lights HYD LOW go out equal or greater than 1,250 psi and vice versa.

 

 

Any news on the non functioning center console red lever emergency brake?

[CW46 101]

A few other points for reference the developer might be interested in looking at for realism regarding systems operation based on the recently uploaded you tube video of the engine startup procedure.

 

1. The starter engagement light is correct when selecting start position, it should be an amber light for the starter and the associated ignition red light should illuminate when the thrust lever is moved from cutoff to idle.Both lights go out around 50% N2. This is controlled by fuel computer action. For simplicity maybe it could be changed to have both lights illuminate when the starter is selected then extinguish when selecting the generator to be "close enough" realism.

 

2. The jet pump switch lights should under normal conditions never have a steady on illumination.The only time that light is on is when the switch is moved to either the on or off position and it is a momentary flash as the valve is positioning between open and close. A possible solution might be to have it illuminate for about a second then go out. Those switches are generally left on all the time and only turned off for specific abnormal conditions.

 

The standby pumps provide the necessary fuel pressure for engine start and that occurs automatically when the starter switch is selected.Later model Lear 35's had a light next the standby pump switches to indicate when those pumps were actually on. 

 

These are minor discrepancies as the model appears to be well done and the manual has pointed out some systems are not accurately functional. I will most likely purchase the product as it appears the developer is making an effort to improve the realism of the systems where it is possible to do so. 

[Flysimware 647]

Great :smile:. Remember the output of the electrically driven aux HYD pump is 1,250 psi...., output of the engine driven HYD pump is: 1,550 psi.

Lights HYD LOW go out equal or greater than 1,250 psi and vice versa.

 

 

Any news on the non functioning center console red lever emergency brake?

I agree but both engines would produce a max of 1,750 PSI

A few other points for reference the developer might be interested in looking at for realism regarding systems operation based on the recently uploaded you tube video of the engine startup procedure.

 

1. The starter engagement light is correct when selecting start position, it should be an amber light for the starter and the associated ignition red light should illuminate when the thrust lever is moved from cutoff to idle.Both lights go out around 50% N2. This is controlled by fuel computer action. For simplicity maybe it could be changed to have both lights illuminate when the starter is selected then extinguish when selecting the generator to be "close enough" realism.

 

2. The jet pump switch lights should under normal conditions never have a steady on illumination.The only time that light is on is when the switch is moved to either the on or off position and it is a momentary flash as the valve is positioning between open and close. A possible solution might be to have it illuminate for about a second then go out. Those switches are generally left on all the time and only turned off for specific abnormal conditions.

 

The standby pumps provide the necessary fuel pressure for engine start and that occurs automatically when the starter switch is selected.Later model Lear 35's had a light next the standby pump switches to indicate when those pumps were actually on. 

 

These are minor discrepancies as the model appears to be well done and the manual has pointed out some systems are not accurately functional. I will most likely purchase the product as it appears the developer is making an effort to improve the realism of the systems where it is possible to do so. 

1. When the fuel computer is on the amber light the only color mentioned in our tech manual will go out when the engine rpm is above 40%. When the fuel computer is off the amber light will remain on until you move the starter switch up. This is how we designed our system.

 

2.I will check the manual and add a timer is you are correct. Thanks!

[Flysimware 647]

Glad to announce i finally after 2 days of many hours solved the issue to produce an auxiliary hydraulic pump. 

 

Here is how the system works.

 

No voltage HYD sw off and engines off the flaps will move very slow from the reserve pressure for emergency's.

With voltage HYD sw off and engines off same result.

With voltage HYD sw on and engines off you get 875 PSI and the flaps will work as normal.

With voltage HYD sw on or off and engine running you will get 1,750 PSI produced from both engines.

 

Will be uploading v1.4 tonight. 

[Flysimware 647]

2. The jet pump switch lights should under normal conditions never have a steady on illumination.The only time that light is on is when the switch is moved to either the on or off position and it is a momentary flash as the valve is positioning between open and close. A possible solution might be to have it illuminate for about a second then go out. Those switches are generally left on all the time and only turned off for specific abnormal conditions.

 

I find that your not exactly correct on how this light works but i found i did make a mistake as the light is on when the switch is not selected. So the light does not need a timer since it's says selected and this means it's not controlled by the valve which would have a delay. So no timer needed it will reverse the light. 

[CW46 101]

The statement in the manual "when not as selected" means that if the switch is moved from from open to close or close to open and the valve does not actually go to the selected position it will it cause the light to illuminate steady.In other words even though the switch was moved the valve did not. We use to call them "agreement lights" did the valve move as it is supposed to? The cross flow and transfer valves operate in similar fashion. It's a flight simulator not a systems trainer and not a big deal, if one was not aware of it nobody would no the difference in flight sim world.

 

Page 5-8 of the pilot training manual under motive flow fuel and jet pumps description, "The amber indicator lights next to the switches illuminate when the motive flow valves are in transit or are not in the position selected on the switch." 

[RobdeVries 28]

Great stuff guys! My compliments to the developer for listening and improving!

 

Now lets make the emergency brake lever functional and were all set :smile:

[Flysimware 647]

The statement in the manual "when not as selected" means that if the switch is moved from from open to close or close to open and the valve does not actually go to the selected position it will it cause the light to illuminate steady.In other words even though the switch was moved the valve did not. We use to call them "agreement lights" did the valve move as it is supposed to? The cross flow and transfer valves operate in similar fashion. It's a flight simulator not a systems trainer and not a big deal, if one was not aware of it nobody would no the difference in flight sim world.

 

Page 5-8 of the pilot training manual under motive flow fuel and jet pumps description, "The amber indicator lights next to the switches illuminate when the motive flow valves are in transit or are not in the position selected on the switch." 

Thanks for the advice on the wording. So your saying the light would only appear if a failure. Which means this light would never show in the sim since the switch position and valve would never get to this scenario.

Great stuff guys! My compliments to the developer for listening and improving!

 

Now lets make the emergency brake lever functional and were all set :smile:

I thought you were talking about the parking brake in the previous post. I will look into this as when i first wrote the code they worked. I have not tested this in a while.