Heyo
Just a question thats been bugging me for a while now...why does the PropPitchMotor (which was an electrical system) on the 109 (also 110) go defective when my engine is dying of overheat/overrev/loss of oil? As long as the battery and the electrical system is in working shape i should always be able to change the proppitch?
Thats actually a very good point.
It's an electrical system that drives a gearbox.Originally Posted by Parrot
Heyo
Just a question thats been bugging me for a while now...why does the PropPitchMotor (which was an electrical system) on the 109 (also 110) go defective when my engine is dying of overheat/overrev/loss of oil? As long as the battery and the electrical system is in working shape i should always be able to change the proppitch?
The governor failure normal a result of (I suspect) oil leaking causing the gearbox to fail.
If it's brown, shoot it down!
Trooper117 liked this post
Does that Gearbox use the same Oil thats in the Engine itself?
I have no idea. Maybe gearbox is not the right word, but there will be a series of gears involved that the electrical motor is driving, whether or not they are wet or dry I don't know. It seems in Clod though that when the oil gasket goes, the 'governor' (whatever that is, gear?) follows shortly after thus leaving you with no prop control.
I have some books on the Luftwaffe engines at home, maybe something in them.
If it's brown, shoot it down!
I can understand that the Hydraulic driven system of the CSPs is failing at the same time as the Engine ,because the Pump was driven from the Engine.
I know im annoying asking this questions...
Edit : Brainfart removed
Last edited by Parrot; Jan-03-2018 at 04:12.
Not annoying in the least, interesting questions, that exceed my understanding of how these systems are linked, or how clod interprets that through the damage model.I know im annoying asking this questions...
If it's brown, shoot it down!
Well I'm at work for my sins with 90% of people still on holiday here, so nothing better to do.
Seems the Hamilton Standard (US aircraft) mechanism relied on hydraulic pressure from the engine oil
http://www.heartlandscience.org/aeroav/prop
http://www.airpages.ru/eng/mn/b20_20.shtml(1) GENERAL. (See figure 113.)-Each engine is equipped with a Hamilton Standard, hydromatic, full-feathering propeller. The nominal diameter of each propeller is 11 feet 4 inches. Each propeller consists of a 23E50 hub and three 6353A-21 blades. A propeller anti-icer system is provided.
(2) FEATHERING SYSTEM. -Fluid for operating the propeller feathering system in each nacelle is provided by the engine oil container in each inner wing panel. A sump at the bottom of the oil container provides a one-gallon oil supply which is available to the propeller feathering system only. From this sump the oil is directed to an electrically operated pump which forces the oil under pressure to a cable controlled propeller governor mounted on the front section of the engine. The pressure of the oil between the pump and the governor may range up to 500 pounds per square inch for feathering and to 600 pounds per square inch for unfeathering the propeller. A switch is provided for each propeller. After pushing the respective switch for the propeller to be feathered, the switch will automatically release when the propeller blades reach their full feathered position. To unfeather the propeller, push in the switch and hold until the engine windmills at 600 to 800 rpm. Then release the switch.
German system appears to be more mechanical
Untitled-1.jpg
If C is the drive from the electric motor, what is 'O'
Untitled-5.jpg
Last edited by Vlerkies; Jan-03-2018 at 05:06.
If it's brown, shoot it down!
http://www.fzt.haw-hamburg.de/pers/S...hPropellor.pdf PAGE 43 and 44
http://aviationarchaeology.gr/wp-con...M-Electric.pdf PAGE 5 "All gear components run in grease" no oil involved it seems
Thanks for that, quite different from the 603/605 engines with the VDM system inside the engine casing.
Any idea what 'O' is?
If it's brown, shoot it down!
If you look at the second document on Page 4 and zoom in theres also Letters for parts... same letters as its seems....O is located next to "Spinner Fixing to Air Screw"...there it looks like some sort of end stops or similar on a sliding part.
EDIT: same picture as you posted farther up....
Last edited by Parrot; Jan-03-2018 at 10:24.
Well the E1 and E3 are totally reliant on pilot input to control the prop pitch to operate within the most efficient parameters for the engine rpm. By implication then they have no governor mechanism at all.
I have long turned off info windows, but from memory if/when the oil gasket ruptures I just climb hard asap pointing the right way and then start to coarsen the prop at the top before the governor failed preventing me from doing so, to try and maximize how far the brick would glide.
Maybe just a generic 109 damage model, but at least now we can really feather the fan up front, progress.
If it's brown, shoot it down!
I'd hazard a guess it's the result of some old, shared damage code between V-12 airplanes in CloD. And if it happens in upcoming 5.0 Tomahawks, I'll be sure of that(Curtiss Electric governor would always operate, with or without oil in the engine).
Well the E1 and E3 are totally reliant on pilot input to control the prop pitch to operate within the most efficient parameters for the engine rpm. By implication then they have no governor mechanism at all.
Maybe just a generic 109 damage model, but at least now we can really feather the fan up front, progress.
Hmm...maybe the automatic proppitch would fail in e-4 and above....but manual should always be an option regardless of engine damage....(like i said as long as battery and electrical systems working)
Very interesting video, do the figures quoted on rpm and ata settings apply for the E1 and E3... or was that for later versions?
I say this because I'm still trying to get to grips with the early versions of the 109.
The prop pitch adjustment was purely electrical in the 109 and needed no pressurized oil. The prop pitch is directly coupled to the ata measured after the throttle valve. If you are in automatic mode and sustain engine damage which affects the supercharger, the automatic prop pitch will try to regulate to the correct pitch at the current ata. If its in manual mode, nothing will happen. You still maintain full control over the prop during an engine fail in manual mode, as long as the electric system is intact.
Hi rel4y
For the 601 engine that seems to make sense, as the VDM mechanism appears to rside in the hub it seems as pointed out by Parrot.
Just as a matter of interest, perhaps you know more, on the 605 it seems they moved this inside the engine casing, and it shows pressurised oil cooling there if I understand this diagram correctly?
DB 605o.jpg
If it's brown, shoot it down!
The DB605 has the planetary gear system integrated into the general oil lubrication of the motor as you correctly suggested. The oil in this case isnt used as a hydraulic transmitter of force, it is just there for lubrication and cooling. If the oil pressure drops due to a fault within the oil system, lubrication will slowly decrease for the whole motor. Now that will not influence the planetary gear system of the prop pitch adjustment by much at all. The torque transmitted by the small electrical motor via the planetary gear system just isnt high enough to cause massive wear or heat. Before the prop pitch mechanism wont work due to underlubrication, you will have a motor failure for sure. But even the motor failure would take around 10 mins as the residual oil film in the running engine will provide some basic lubrication before the engine will seize up for good. Even when the engine seized to function the prop pitch adjustment should work on battery.
Vlerkies liked this post
So in conclusion should we open a new Bug/Feature for that on the Bugtracker?
Vlerkies liked this post
Would not hurt, and maybe can be looked at closer by those in the know before TF5.0
If it's brown, shoot it down!
https://www.tfbt.nuvturais.de/issues/1040
Last edited by Parrot; Jan-08-2018 at 08:30.
Propeller governor is the intelligent controller. Propeller drive is what moves the propeller physically.
In most hydraulic constant speed propeller it is not possible to have control over propeller pitch if governor fails. The pitch will usually fail flat in single engine or feathered in multi-engine by design or possibly freeze in place if damaged directly. But for DB600/VDM electric propeller drive in many cases there is no governor except the pilot's brain and switch. In cases of automatic VDM there is some smart box which is pressing the electric switch instead. If smart box fails it is possible to revert to manual operation usually.
There comes the question of what are failure modes under damage which do and do not preclude manual (or auto) operation of propeller pitch in VDM system. If electric motor or mechanical linkage is damaged then adjustment may be impossible. Engine oil temperature overheat (100-200C) or loss (plumbing rupture to cooler) generally should not have an adverse effect on the system. Electric motors usually tolerate contact with oil of reasonable temperatures up to and including submergence.
Simple overheat of oil failure in CLoD assuredly leads to loss of governor in a short time frame in all airplanes probably attempting to model failures of the constant speed or otherwise hydraulically-actuated type (2-stage). Probably the most likely failure mode would be not only loss of pilot control but an uncommanded change of pitch to physical limits. By design usually failures of the propeller pitch adjustment system in hydraulically-actuated types is to minimum pitch for single engine and maximum pitch for multi-engine by a strong preload spring. A "freeze in place" pitch failure is perhaps the least likely.
For a simple failure of oil supply the VDM-automatic should be generally unaffected and if the automatic control system is damaged manual control is possible. Physical electrical control should be impossible in cases of drive failure and electrical supply failure. Possibly the VDM-electric propeller airplanes should not contain the "governor" component at all and instead have "propeller drive" and "propeller automatic control" components instead. Thus the electric pitch system can be decoupled from the overall hydraulic-oil health of the engine.
Vlerkies liked this post
I suspect a bug. As every time I take off with the auto prop pitch engaged on the E4 from spawn and engine start, the prop pitch governor fails soon after takeoff, and the prop unwinds to increasingly course pitch, till the load on the engine stalls the engine. Before then you have to turn off the auto pitch, and manually adjust to fine pitch to fix it. And even then, after you have selected say 2400 rpm, and re-engaged the auto pitch, I have also had the auto-pitch then fail again, and let the engine over rev, till the engine fails and your engine lubricant is on the outside of the plane!Heyo
Just a question thats been bugging me for a while now...why does the PropPitchMotor (which was an electrical system) on the 109 (also 110) go defective when my engine is dying of overheat/overrev/loss of oil? As long as the battery and the electrical system is in working shape i should always be able to change the proppitch?
You should check the position of the lever/switch. In multiplayer the Bf-110's prop switches are stuck upward at start. I think in Bf-109's case they are stuck down. So you have to disable auto (for models which have it) and wiggle the levers to have them return to neutral, then reengage auto. It is best to set the "clock" some angle other than limits (if 12:00 is maximum, set ~11:45) and then watch when you toggle automatic control back on that clock moves accordingly.
ATAG_kiwiflieger liked this post
For your attention:
VDM_VariablePitchMechanism.pdf
Prop pitch control is cut in 109 when electrical systems are damaged. Experienced it a couple of evenings ago which reminded me of this thread. If, as it seems, the 109 governor is electrically driven, could the governor failure critical be removed from the oil rad damage pathway?
Found something interesting!
This is for the DB 601 NAs the controlling energy
is separate from the engine, the airscrew can be feathered
with the engine stopped. The blades are interchangeable,
and a blade can be removed for inspection and replaced in
about 20 minutes. The total weight of th e airscrew is
304 lb., including the motor bracket and wiring.
here http://kurfurst.org/Engine/DB60x/fil...01N_Engine.pdf
page 369 (PDF page 5 bottom right)
I always thought that the pitch controller failed because the violent shaking of the drive shaft made the unit to seize up.
Posting Permissions
Reply With Quote
Bookmarks