Tuesday, October 27, 2009

F7F update

Right after I released version one of the F7F I found that it wouldn't climb above about 9200 feet. Ron Jensen recommended an auto-mixture controller, and this did the trick! Adding the auto-mixture system required changing the binding for the 'Shift-Q' key, which now shuts the engines down by turning the magnetos off/on.

Version 1.1 is posted now.


  1. Hehehe, I nearly asked if it was above 9000 feet seeig your post last night, but then demured, thinking : "Nah, Dave cannot possibly have forgotten about mixture control, no way !!!"
    Looks like I could have mentioned it (m/M being the standard fgfs shortcuts for mixture)

    Granted, you fly turbofan airliners for a living, not piston props :)

    So the system sets mixture for efficient combustion while maintaining a safe temperature ?


  2. Last time I flew a piston powered airplane was in 1978, and I don't remember a thing about it :) Fortunately I have a few antique aeronautics books I've collected over the years that have some information on recips and props.

    I just posted a new version of the AD-4 project which has the automixture system. It just uses "delta" (pressure ratio) as the mixture setting, without regard to CHT. Good enough for now. There's really not enough room on the panel for all the gauges a recip airplane needs, so I'll have to simplify some things.

    I've discovered that propeller-pitch of zero gives low prop rpm, and propeller pitch of one gives high prop rpm.

    BTW, I figured that since I know the prop gear ratio I can adjust the prop spin animation to use engine rpm, multiplied by a factor based on gear ratio. That solves the problem of not having prop rpm going over the MP protocol.