Hello FE/FE2 flyers,
Here's one more over-compressed engine that I've overhauled, for one of my favorite planes - the Pfalz Dr.1. This one is now powered by the over-compressed variant of the Siemens-Halske engine (the III.a variant).
Historical stats. for the over-compressed engine:
6.0:1 compression ratio (high for the WWI period)
160hp @ 900 engine rpm
200hp @ 950 engine rpm
240hp @ 1000 engine rpm (over-compressed; for short periods, below about 1500-2000 m alt.)
(could output 160hp @ full throttle as high as 3700 m alt.)
Other interesting details about the engine:
Propeller and 11 cylinders spin in one direction, the crankcase in the other (see TheAerodrome.com for more info.)
Historical stats. for the uncompressed III (not III.a) variant:
160hp @ 900 engine rpm
200-210hp @ 950-970 engine rpm
Stats. for the Sh.IIIa-powered Pfalz Dr.1 in FE2 after the FM overhaul are:
- very short run-up for takeoff @ full throttle (less than 30-40 meters)
- take offs are fine @ about 100 kph
- powerful engine allows level flight, even gentle/longer-run take offs, @ about 50% throttle
- stalls below low 70s/high 60s kph in a climb, similar stall in straight line (mid-60s kph)
- tends to slip out of very tight turns and very tight loops on occasion, at speeds as high as 130s/140s kph (in gentler turns slips happen below about 100-110 kph); symptoms not as noticeable as on Pfalz. D.III/IIIa, and easier to correct
- top speed at full-throttle (over-compression near sea level): 202 kph
- cruise speed @ 80% throttle (near sea level): 174-5 kph
- climb @ 80% throttle in 120s kph to about 1000 m alt.: 7-8 m/s (amazing climb rate even with non-overcompressed throttle, better than the Fokk. Dr.1 and D.VII/VIIf, thanks to its three wings, powerful engine, and better aerodynamic qualities/slipperiness than on the Fokk. Dr.1; also has thinner airfoils than the Fokk. Dr.1 but not as thin as on allied types such as the SPADs, Se5a, etc.)
1000 m alt: 196-7 kph @ 100% throttle
1500 m alt: 190-1 kph @ 100% throttle (this is the sometimes-cited top speed for the Pfalz Dr.1)
3000 m alt: 178-9 kph @ 100% throttle
4000 m alt: 170 kph @ 100% throttle
5000 m alt: 160-1 kph @ 100% throttle
6000 m alt: 153 kph @ 100 % throttle
(theoretical ceiling for Sh.IIIa variant is about 6300 m)
6500 m alt: 81-2 kph @ 100% throttle (easily falls into 70s kph and stalls/spins here; notice also the drop off in top speed since the theoretical ceiling has been passed by about a couple of hundred meters)
- climb rate @ 100% throttle from about 1500 m alt. to 5000 m alt. is fairly consistent @ about 120 kph, averaging 8-9 m/s (very impressive for a WWI type); drops to about 5-6 m/s @ 120 kph and full throttle beyond about 5000 m alt; going into the 130s kph to climb beyond 5000 m alt improves the rate slightly to about 7-8 m/s (again @ full, over-compressed throttle)
- the Pfalz Dr.1 is on average about 10 kph slower at the higher altitudes than the 200 hp Alb. D.Va and the Fokk. D.VIIf, but the climb rate is better by about 3-4 m/s (a noticeable difference)
- approximate engine rpm equivalents and throttle settings seem to be as follows:
100% (over-compressed) throttle: about 240 hp (this gives you as much power as the later SPAD 13, the Ansaldo, also the high-compression Fokkers and Albatroses; and don't forget the improved climbing power you have)
80% (normal) throttle: about 200-210 hp
50% (half) throttle: about 150-160 hp
25% (quarter) throttle: about 80-100 hp
- to land, cut the throttle to idle since otherwise you already have ample power; or switch off the engine
- avoid rough exits from dives exceeding about 250 kph; type dives easily to nearly 400 kph on full power; model now has MaxG limits implemented and is more realistic; also with improved damage ratings included, and a new sound for the Siemens-Halske engine
- if you want a Pfalz Dr.1 with the uncompressed variant of the engine, Sh.III (160 hp, max 210 hp), include the following changes in your data ini:
under MissionData:
change service dates to April-July 1918 (educated guess for the end date)
also change the ceiling to between 5800-6000 meters
under the Engine section, paste over the following entries, for the relevant sections (which will give a top speed of about 200 kph near sea level, another often cited number for its top speed):
AltitudeTableNumData=23
AltitudeTableDeltaX=504.8
AltitudeTableStartX=0.0
AltitudeTableData=1.000,0.996,0.988,0.982,0.964,0.945,0.927,0.909,0.891,0.873,0.855,0.836,0.818,0.800,0.782,0.764,0.745,0.727,0.709,0.691,0.673,0.655,0.000
Happy flying,
Von S
[Files included in ver. 9.0 and later of my FM updates pack.]