Sorry for misunderstanding. I found this:
It is from a post ex 2015 on this forum (search for ships reverse)
Hi,
The last three weeks I have been concentrating on creating a reverse thrust for ships with a piston engine. There are many very nice freeware pilotable ships available for FSX, but they nearly all lack a reverse thrust. I had several conversations with Michel Paquet who has published on these forums his quest to create his own ship from scratch. I am very grateful to him that he shared very openly his experiences with me. This + all other things I've been reading through, lead me to the conclusion that Flight dynamics editing is often done on a trial and error base.
So i wanted to find out if, for the reverse thrust, there was'nt a universal method that could be applied.
Therefore first a small theoretical framework, but as simple as possible (my excuses to people who know much more about this and who'll say that I am oversimplifying):
A piston engine in FSX delivers forces that make a shaft turn in 1 direction only (clockwise). That movement can not be reversed (i.e. anti clockwise). So reverse thrust does not come from the engine.
On the shaft sits the propellor.
There are 2 kinds of propellors.
A fixed gear propellor that can not create a reverse thrust,
and a constant speed propellor that can.
Why? Because it can feather. This is what happens when you feather a propellor:
So it can create a reverse thrust, because it can change the angle of attack of the blades in the air or in the water.
Back to FSX:
It is actually rather simple to create a reverse thrust for a ship.
You go to the aircraft CFG file, look for the propeller section and see that you set the following parameters:
propeller_type= 0
beta_max= 65
beta_min= 15
min_gov_rpm= 500
prop_feathering_available= 1
prop_auto_feathering_available= 1
min_rpm_for_feather= 500
beta_feather= -65
prop_reverse_available= 1
minimum_on_ground_beta= 1
minimum_reverse_beta= -14
The rpm values may somewhat vary and the beta values (feather angles) are not absolute either. But I am pretty sure that the reverse beta must be a negative value.
And maybe a propeller with 4 blades works better for a boat, but I don't know for sure.
How do you make this work when piloting?
Pushing first F1 and then F2 will not work.
There is a command Cntr+F2, that is often misunderstood. In most literature it says that it reduces the RPM. But in Microsoft literature I found that it actually decreases the propellor beta (angle of attack of the blades), which means that it is the feathering command.
So if you are piloting a ship and want to reverse:
Push F1 first, keep Cntr+F2 down for some seconds, give throttle again and you'll be in reverse.
To return to normal thrust: again push F1, then Cntr+F4 for some seconds and give throttle again.
Voilà, problem #1 of the pilotable shipping solved.
Up to the next one: improving the autopilot tracking...
Cheers
Marcel