Super Constellation Sim - How to do a propeller reverse?

[SuperConnie]

I am now in the "hot" phase of my Connie Sim project... all kind of wiring and programming. I have now the necessary interfaces from Simkits and so far there are no problems except one:

I would like to have working propeller reversers and I don't know how this could be done.

I have to explain that I'm using original hardware from a real airplane and therefore I am a bit restricted with the possibilities. The original prop reverser works with electric switches that tell the propeller to go into reverse if you pull the reverse levers. If you pull them further, the throttles will be opened up to approx. 30%, causing the engines to power up and blow lots of air backwards to slow down the plane.

In fact it is possible to taxi the plane backwards (in reality!) but "you have to be very careful with the brakes or you will fall on your tail" (Flight engineer)

Now... is there a possibility to tell the MSFS to reverse the props by a switch (or 4 switches for 4 engines) and to create "negative thrust" with the throttle levers??? If that does not work, the prop reversers will do excactly the opposite of what they are intended for because they open the throttles.

Christian

PS: If interested in my work progress, please visit http://conniesim.blogspot.com

[Pete Dowson]

I

I would like to have working propeller reversers and I don't know how this could be done.

I have to explain that I'm using original hardware from a real airplane and therefore I am a bit restricted with the possibilities. The original prop reverser works with electric switches that tell the propeller to go into reverse if you pull the reverse levers. If you pull them further, the throttles will be opened up to approx. 30%, causing the engines to power up and blow lots of air backwards to slow down the plane.

The electric switches probably simply operate an interlock.

I'm not sure whether you are talking about thrust levers/throttles or propeller pitch reversal, which I thought was the normal way to engage reverse on such aircraft. assuming you mean prop pitch not throttle then:

A reverse propeller pitch can be achieved on suitably equipped FS models by calibrating, in FSUIPC, on the 4 Propeller Pich page. This offers a central "feathered" or "idle" zone, which should be calibrated to coincide with some sort of lock or detente on your levers. The region below (nearer to you) would be the revere pitch range.

I'm assuming you have two or more prop pitch levers, either one for each engine, or at least one for engines 1 and 2 and another for engines 3 and 4. For two levers you'd assign one in FS to engine 1 and the other to engine 2 then select the map 12->34 option in FSUIPC. For 4 levers you simply assign them individually, no problem.

If you only have one lever you'd need to select "map to 4" option on the first or second calibration page in FSUIPC, then move to the 4 prop page.

If you do really mean thrust reversers, on the throttle levers, then the process is similar but obviously performed then on the throttle assignments and FSUIPC's 4 throttle calibration page.

Regards

Pete

[SuperConnie]

A picture says more than 1000 words:

There are 4 reverser levers linked to the throttles. If you pull them up, the switch is activated that tells the prop to go into reverse pitch and in the same time the throttle is opened to increase engine RPM. This is independent from the settings of the prop pitch lever.

Let's see if I understood you right... You say that I can use the propeller pitch adjustment to create a negative pitch in the MSFS... I have the possibility to connect a potentiometer to the pitch input of the Simkits Central Control Unit (CCU). If I would use a fixed resistor and the switch to turn it on or off (or to switch between two values) then I could use FSUIPC to assign a corresponding normal or reverse pitch.

If that works, my problem is solved :-)

What about the "Joysticks settings 11"... separate reversers... is this not what I need?

[Pete Dowson]

There are 4 reverser levers linked to the throttles. If you pull them up, the switch is activated that tells the prop to go into reverse pitch and in the same time the throttle is opened to increase engine RPM. This is independent from the settings of the prop pitch lever.

That sounds exactly like normal jet reversers. There are facilities in FSUIPC for assignment of up to 4 reverser levers as axes (not switches), and the reversers then act as throttles, pulling back further increases the reverse thrust.

It seems odd that with a prop you get reverse thrust with the prop pitch staying the same -- or are the engines actually rotating the props the other way, i.e. against the normal pitch?

Let's see if I understood you right... You say that I can use the propeller pitch adjustment to create a negative pitch in the MSFS.

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Well, assuming the FS model has that enabled, yes. Have you not tried experiementing just using the mouse or keyboard controls on the default graphic quadrant? I think you need to experiment first to see what it is you really need to do. Once you are sure I can advise you further.

What about the "Joysticks settings 11"... separate reversers... is this not what I need?

If you are talking about true thrust reversal, using throttles, yes. I though prop reversal was by reversing pitch. But I must admit to knowing very little about all this. I fly a 737 or a Piper Arrow III.

Regards

Pete

[SuperConnie]

Well... I will have to ask a pilot to be sure but as far as I understood it, the propeller pitch can be changed by a small lever next to the throttles. But normally you don't need that because the pitch is adjusted automatically. Prop feathering is done by pushing a big red switch or if the engine RPM drops below a certain value.

Prop reverse is activated by the switch that is connected to the reverser lever. It does in fact set the props to a negative pitch which causes them to work backwards. But for this you don't have to change the pitch lever setting. If the reverser is deactivated then the propeller goes to the normal pitch that is set by either the automatic or the pitch lever.

The Super Constellation has many cool features for an airplane of those days. Even stuff like auto throttle was available but I'm not building this into my sim.

[Pete Dowson]

Well... I will have to ask a pilot to be sure but as far as I understood it, the propeller pitch can be changed by a small lever next to the throttles. But normally you don't need that because the pitch is adjusted automatically. Prop feathering is done by pushing a big red switch or if the engine RPM drops below a certain value.

Well in FS that might possibly be done by the clever programming in the model you have, but otherwise, in the inbuilt FS controls, it's certainly within the continuous range of a prop pitch control which can go down through zero (feathered) into negative values (for reverse).

Prop reverse is activated by the switch that is connected to the reverser lever. It does in fact set the props to a negative pitch which causes them to work backwards. But for this you don't have to change the pitch lever setting. If the reverser is deactivated then the propeller goes to the normal pitch that is set by either the automatic or the pitch lever.

If that is how it is implemented in your FS model, so be it. In that case you don't need any fancy reverse pitch calibration in FSUIPC or anything else, you simply need to assign a button.

Why don't you try the model you have and see how it actually works in the Sim? Then you can look at how to emulate that on external controls.

Regards

Pete

[SuperConnie]

Hi Peter

I was writing about how the stuff works in the REAL airplane. If I remember right the FS model does not have this functionality... I have to ask the programmers how they solved that problem.

Christian

[Pete Dowson]

I was writing about how the stuff works in the REAL airplane.

Ah, sorry, FSUIPC won't work in a real airplane! It needs FS. ;-)

If I remember right the FS model does not have this functionality... I have to ask the programmers how they solved that problem.

Yes. Using FSUIPC to interface to an aircraft in FS cannot remodel that aircraft.

Regards

Pete