Re: Rules of thumb...

On Monday 20 Jun 2005 21:51, Andy Ross wrote:
> Lee Elliott wrote:
> > Does the code include the prop-pitch governor?  I was sort
> > under the impression that it did but that didn't seem to
> > gibe with controlling the prop rpm using the pitch control. 
> > Am I in fact doing what the governor does?
>
> I may be misunderstanding the question, but yes.  The
> propeller code for constant speed props simulates a governor
> which automatically seeks to a the selected RPM.  This is used
> by the solver also, so you can just specify the position of
> the pitch lever and expect to see the same results at runtime.
>
> There is also a manual-pitch attribute you can set, but this
> feature is really touchy and hard to get right.  You need to
> get the pitch dead-on at solution time (the job the governor
> does for you normally) in order for the resulting propeller to
> match the engine properties at runtime.
>
> Andy

(Hmm... this didn't seem to make it to the list the first time I 
sent it - I had to copy it out of my 'sent' folder.  Apologies 
if everyone has already recieved it)

I had another chance to play with it this evening.

I removed the control-settings entries I had for the 
propeller-pitch, along with the propeller-pitch control-input 
axis for the propeller-pitch within the propeller section.  Then 
I added a control-output on the ADVANCE control and pointed it 
to /engines/engine[0]/propeller-pitch.

When I tried running fg I could then see the prop-pitch being set 
by the governer code.

The pitch seems to be dropping to 0 far too quickly though and I 
still can't get a config that doesn't loop if I add a 
control-input for the condition:(

The cruise RPM is being sought ok but I can't seem do anything to 
to get the higher rpm for take-off.

LeeE

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