Radial Engine Start up

[PeteHam]

I've had the Flight Replicas Douglas C-54/DC-4 for some time now, but the thing that is unrealistic (for me) is the engine start.

When starting the engines the props go from zero to 1000 rpm in a split second.

Is there any way to extend the time for the engine start sequence?

Thanks for any help.

Pete.

[Mike71]

In the aircraft.cfg under the section [piston_engine] is a line entry
normalized_starter_torque= 0.1 //Starter torque factor

This can be edited (decreased in your case) as desired as long as the engine will eventually start.


Try editing the line as follows:
normalized_starter_torque=0.075 //0.1 Starter torque factor


or however you desire to get results.


Using the // feature allows you to quickly edit and reload/test the plane while making small changes. FS9, FSX, P3D etc ignore everything after the // characters

[stansdds]

Without custom coding, truly realistic piston engine starts are not possible with FSX or any of the previous MicroSoft flight sims. MS coded the sim for turbine engine start, so the engine needs to be turning 500 rpm before ignition can occur.

[Mike71]

Try 0.009; engine crank will be slower, spike at about 750 RPM and settle at about 725 RPM at idle (P3d4 model version)

If you watch "American Graffiti" someday, the last scene shows one of the characters boarding what appears to be a DC-6 (different engines, I know).

In those days, they boarded through the rear door and engines often started before everyone was aboard. You can see engines 1 and 2 start - they fire up rapidly after only a turn or two. Of course the engines were likely warm at a stopover flight for pax pickup.

[tgycgijoes]

Just for curiosity I opened up my FSX default DC-3 to see what their aircraft cfg values were: their piston power scaler was 0.3 and in was the engine turbocharged the sillies answered TRUE or an "=1". Written for tyrbo-powered aircrafts. Also why you have to adjust the taxi speeds of the aircraft that tend to run down the taxiway at 40 knots.

See what happens above reducing the value. Also check what the Team C-47 V3 values are for those. I believe that theirs is probably very accurately modeled at least IMHO.

[PeteHam]

Thank you for your comments.

I've tried various numbers, so far I've got it down to 0.001 and it is only fractionally slower.

I'll keep tweaking to see if it changes for the better.

Pete.

[Mike71]

Just for curiosity I opened up my FSX default DC-3 to see what their aircraft cfg values were: their piston power scaler was 0.3 and in was the engine turbocharged the sillies answered TRUE or an "=1". Written for turbo-powered aircrafts. ----

Turbocharged =1 just means it has a blower (mechanical supercharger or turbocharger). Most C-47/DC-3s had a single stage mechanical blower, non selectable. You can always tell if a plane has one because if it can pull more MAP than outside barometer reading (about 29.92 at sea level takeoff on a standard day) it has a boosted engine of some type.

[stansdds]

Mike71 is correct, the turbocharger line in the cfg is how MS tried to handle supercharging with piston engines. It simulates a single stage, single speed supercharger well enough, but does not handle the more complex multi-stage and multi-speed superchargers found on many aircraft made after the late 1930's. Again, correct supercharger functions are possible, but only through custom gauge coding.

[tgycgijoes]

I always learn something new every time I visit a new thread here. Thanks for all the input about REAL specs for the aircraft.

[Mike71]

Mike71 is correct, the turbocharger line in the cfg is how MS tried to handle supercharging with piston engines. It simulates a single stage, single speed supercharger well enough, but does not handle the more complex multi-stage and multi-speed superchargers found on many aircraft made after the late 1930's. Again, correct supercharger functions are possible, but only through custom gauge coding.

A agree with stansdds. It can also represent a turbocharger, as applied in many newer civil props like a turbo'd AZTEC, Cessna 421 etc, or a military P-38, B-17 or B-24. However it in general gives only a basic simulation in order to provide higher MAPs at takeoff and at altitude.

The Navy did not use turbo's on carrier based planes because at the time they were fussy, somewhat unreliable and the limited maintenance assets on a carrier just made them "too much of a PIA". The Navy had looked at several designs that proposed their use but in the end, mechanical single and 2-stage blowers were the final choice.