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rhodges

Archer III Question or two:

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I sure don't want to be looking a gift horse in the mouth and highly recommend this JustFlight bird. Thanks loads for the Christmas present JustFlight.I would have put this in the JustFlight Forum, but they do have instructions to not put technical questions there. I do have a couple of questions realitive to realizm which are certainly no biggies as follow:1. With increasing altitude, RPM with a fixed pitch prop does not decrease. My assumption is that this is simply the way the bird was modeled and nothing can be done about this.2. Secondly, my Archer is approximately 20 knots short of spec cruse speed. I never flew an Archer III, but have quite a few hours in the predessor 180 Cherokee which if I am not mistaken is pretty much the same bird of a feather. It has been a long time, but best I remember the cruise envelope for somewhere between 7,000 and 7,500 MSL would be somewhere between 2,250 and 2,400 RPM, and 75% power resulted in a speed of approximately 120 to 125 Knots. My JF Archer flies in the low 100's. Surprisingly in the "aircraft.cfg" compared to other FS Aircraft where the "Piston Engine Power_Scaler" could be edited, this seems to have little affect on the Archer. However, I did discover that by increasing the "Propeller Thrust_Scaler" to 3.50, and reducing the "Piston Engine Max_rpm_mechanical_efficiency_scaler" to 0.60 that cruise speed pretty well fell into real world envelope defined above. This also required that the "GeneralEngineData fuel_flow_scalar" needed to be edited to 2.50 in order to retain a reasonably accurate fuel burn.While RPM and cruise speed may be more desirable by doing this, there are two decisive downsides. As expected, takeoff roll now is a bit too swift due to the increased power. I guess some could option the half speed bit but that is also a bit dingy. The second downside is that "brakes toe_brakes_scale" will have to be increased as well. Even then at virtually any high setting I selected, you still will not be able to totally lock the brakes for runup. The aircraft will want to slightly creep.If anyone chooses to try these settings (or any others), be sure that you backup your original default "aircraft.cfg" before doing anything. Then you can return to go if something starts to smell bad.If anyone knows of a method to get reduced power as altitude increases, and/or a better method to achieve more realistic cruise altitude, the info sure would be appreciated.Again, this is in no way meant to flame or complain about this dandy contribution by JustFlight. Just trying to see if there might be a way to improve these two items whch are by no means biggies.Respectfully:RTH

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