Bf109E-7 - throttle surges

[Yardstick]

There appears to be something odd going on with the E-7 Trop (haven't tested the other E-7s yet) but I am getting really weird throttle surges even even when the throttle input remains unchanged. 

 

I couldn't work out why I kept blowing engines in the E-7 as I am very careful about keeping manifold pressure to 1.2 ATA in combat save for short bursts of extra power (1.35 ATA - I rarely if ever use 1.42).  My Cougar throttle has AB indents with the highest set at between 87-90% of throttle travel, which corresponds to 1.2 ATA  in the later E series - so I am confident that I can keep the ATA out of the red.  However, the engine keeps surging to 1.35 ATA, even if the throttle does not move.  My first thought was a throttle sensor spike but I have a contactless sensor and cannot replicate the spiking in the TM joystick analyser - the throttle track is perfectly smooth.  

 

I don't have any issues with other 109s or any other aircraft for that matter, so it seems to be a E-7 thing.  I'll do further testing and keep an eye on the in-cockpit throttle to see if it moves when the engine surges.

 

Anybody else seen anything similar with the E-7?  

[OBT-Mikmak]

Everthing works well in my E7 (Saitek X65F)

[Yardstick]

Update:  It seems to specific to one particular mission.  I converted the Eagles over Tobruk mission no. 4 to a single mission.  Every time I fly it (E-7 Trop is the default aircraft) I get these weird throttle surges.  I can't replicate them in any other mission and I even when I swapped the E-7 for an F-4 Trop and I get had the same erratic throttle behaviour. 

 

It's just about the oddest thing I've seen in 30 years of flight simming - I can't for the life of me work out why this particular mission would generate this sort of stranger controller behaviour ?  It worked fine as a campaign mission.

 

On a side note, there appears to be something very wrong with the F series prop governors - certainly compared to the E series.  If you try an land using auto prop pitch, at idle the prop struggles to get above 9 0' clock.  If you set it to 12 O' clock manually, you red line at 210km with the throttle below 0.6 ATA.  It's even worse on take off in manual mode with a huge overspeed (in excess of 3,000 rpm at 1.3 ATA) well before take off speeds are reached if you use the correct 12 O' Clock setting. 

[Buzzsaw]

36 minutes ago, Yardstick said:

Update:  It seems to specific to one particular mission.  I converted the Eagles over Tobruk mission no. 4 to a single mission.  Every time I fly it (E-7 Trop is the default aircraft) I get these weird throttle surges.  I can't replicate them in any other mission and I even when I swapped the E-7 for an F-4 Trop and I get had the same erratic throttle behaviour. 

 

It's just about the oddest thing I've seen in 30 years of flight simming - I can't for the life of me work out why this particular mission would generate this sort of stranger controller behaviour ?  It worked fine as a campaign mission.

 

On a side note, there appears to be something very wrong with the F series prop governors - certainly compared to the E series.  If you try an land using auto prop pitch, at idle the prop struggles to get above 9 0' clock.  If you set it to 12 O' clock manually, you red line at 210km with the throttle below 0.6 ATA.  It's even worse on take off in manual mode with a huge overspeed (in excess of 3,000 rpm at 1.3 ATA) well before take off speeds are reached if you use the correct 12 O' Clock setting. 

You should not be using Manual prop pitch for landing or takeoff... no need.  In fact, manual should only be used if your auto is damaged in combat.

 

When landing, after deploying flaps and gear, you should be using high rpm and throttle... the aircraft will stall if you don't.

 

When taking off, don't use flaps... just gradually increase throttle to maximum and let the aircraft basically fly itself off... just a small tug after 180 kmh.

[Indianer]

1 hour ago, Buzzsaw said:

You should not be using Manual prop pitch for landing or takeoff... no need. 

The flashcards say something else..

[Yardstick]

Hi Buzzsaw

 

Thanks for the reply but your info on the 109 goes against everything I understand to be correct and also directly contradicts your own manuals (flashcards) which specify the use of manual prop pitch for both take off and landing.

 

 

If you follow these instructions (which upwards to 5,000 hours flying 109s in various sims tells me is correct), then the engine blows as a result of a huge overspeed seconds after take off (see following screenshot).  

 

 

For comparison, these are the instrument readings for the F-2 in IL2:GB following the procedure set out in the CLOD Blitz manual (next pic). Actually I used 1.4 ATA in GB and only 1.3 in Blitz.  I even left the prop at 12:30 which is the finest setting for the F to K in GB (not sure why they are different from the E in this regard or which sim is correct). Had it been set to 12, then the rpm would not have gone above 2,500.

 

 

In GB when landing I will rarely need to use manual as the governor will reliably adjust to 12 O' clock.  If I fly the same curved approach in Blitz, the governor seems initially to adjust the prop pitch to a coarser setting (which in itself seems odd) but even at approach speed (200kph) will not go below 9 O' clock.  For comparison the last pic shows the instruments in the 109F-2 in GB as I start to roll out of my turn on finals with the prop on auto. 

 

 

For comparison the governor as well as manual settings behave as I would expect them to in the E series and consistent with the E-7 in GB.  The problem seems to be with the F series.

Edited August 18, 2020 by Yardstick

[Charon]

I saw this in Eagles over Tobruk as well, but it wasn't #4, I don't think. Maybe #6? I don't think it can possibly be anything about the mission itself, but I'm also not sure how I was mishandling the engine.

[Sokol1]

17 hours ago, Yardstick said:

Update:  It seems to specific to one particular mission.  I converted the Eagles over Tobruk mission no. 4 to a single mission.  Every time I fly it (E-7 Trop is the default aircraft) I get these weird throttle surges.  I can't replicate them in any other mission and I even when I swapped the E-7 for an F-4 Trop and I get had the same erratic throttle behaviour. 

 

In one of the standard Quick Mission of Channel map something similar happens with Spitfire, having been observed by different players, at the time we concluded that this happens when a certain condition is met, it seems to be the proximity of the enemy plane. There's a topic about ATAG.

 

Probable a bit of code loose...

Edited August 18, 2020 by Sokol1

[Buzzsaw]

22 hours ago, Yardstick said:

Hi Buzzsaw

 

Thanks for the reply but your info on the 109 goes against everything I understand to be correct and also directly contradicts your own manuals (flashcards) which specify the use of manual prop pitch for both take off and landing.

 

 

If you follow these instructions (which upwards to 5,000 hours flying 109s in various sims tells me is correct), then the engine blows as a result of a huge overspeed seconds after take off (see following screenshot).  

 

 

For comparison, these are the instrument readings for the F-2 in IL2:GB following the procedure set out in the CLOD Blitz manual (next pic). Actually I used 1.4 ATA in GB and only 1.3 in Blitz.  I even left the prop at 12:30 which is the finest setting for the F to K in GB (not sure why they are different from the E in this regard or which sim is correct). Had it been set to 12, then the rpm would not have gone above 2,500.

 

 

In GB when landing I will rarely need to use manual as the governor will reliably adjust to 12 O' clock.  If I fly the same curved approach in Blitz, the governor seems initially to adjust the prop pitch to a coarser setting (which in itself seems odd) but even at approach speed (200kph) will not go below 9 O' clock.  For comparison the last pic shows the instruments in the 109F-2 in GB as I start to roll out of my turn on finals with the prop on auto. 

 

 

For comparison the governor as well as manual settings behave as I would expect them to in the E series and consistent with the E-7 in GB.  The problem seems to be with the F series.

This will be changed in the flashcards... not necessary to be in manual.

[Wolfstriked]

I found a video from IIRC karaya where he says that due to a bug in COD you have to set pitch to manual,raise to 12:00 to avoid and I wonder if thats where the flashcards went wrong....it does make sense to place it in manual to ensure max revs though so.....

Edited August 18, 2020 by Wolfstriked

[Yardstick]

48 minutes ago, Buzzsaw said:

This will be changed in the flashcards... not necessary to be in manual.

 

My point is that the manual is correct.  There procedure is consistent with that set out in IL-2:GB and DCS (extract for the K-4 below).  I don't speak German, so can't provide primary sources but I trust the other two sims (both their documentation and how the prop governors are modelled)..

 

 

The problem is how the prop governor for the F series appears to be modelled in CLOD.  As I have said the late E series (E-4 and E-7) behave as they should.  However, the Fs are very wrong.  When manually set to fine pitch (12 O' clock), with an ATA of 1.3, the U/min should be c. 2,500.  In CLOD it's closer to 3,500 resulting in a blown engine.  On auto, the above settings result in the governor setting the prop to c. 9 O'clock (much too coarse). 

 

Either the min-max values and ranges for the prop pitch indicator need to be adjusted or the prop pitch is calibrated incorrectly which must have a significant effect on acceleration and torque not just on take-off but more generally.

 

[Buzzsaw]

On 8/18/2020 at 5:14 PM, Yardstick said:

 

My point is that the manual is correct.  There procedure is consistent with that set out in IL-2:GB and DCS (extract for the K-4 below).  I don't speak German, so can't provide primary sources but I trust the other two sims (both their documentation and how the prop governors are modelled)..

 

 

The problem is how the prop governor for the F series appears to be modelled in CLOD.  As I have said the late E series (E-4 and E-7) behave as they should.  However, the Fs are very wrong.  When manually set to fine pitch (12 O' clock), with an ATA of 1.3, the U/min should be c. 2,500.  In CLOD it's closer to 3,500 resulting in a blown engine.  On auto, the above settings result in the governor setting the prop to c. 9 O'clock (much too coarse). 

 

Either the min-max values and ranges for the prop pitch indicator need to be adjusted or the prop pitch is calibrated incorrectly which must have a significant effect on acceleration and torque not just on take-off but more generally.

 

We will look at this.

[LLv34_Flanker]

S! 

 

The automatic still has the bug where you blow your engine. I always switch to manual and set prop to 11:30 and then back to automatic. This is stated in pilot's notes too as a procedure. 

 

I have no idea what values are used for the reduction gear, but DB601 on 109 had 1:1,55 and 110 had 1:1,88. DB605 had on 109 ratio of 1:1,685. This means on 605 that at maximum engine 2800rpm the propellor rpm was 1660.

 

Also how the governing system was adjusted on 605 as follows(info handily in front of me). Up to 5.7km the ratio was 1.0ata/2000rpm, 1.15ata/2300rpm and 1.30ata/2600rpm. Above 5.7km manual setting was to be used for desired ata/rpm setting, but automatic worked too. 

 

 

Edited August 22, 2020 by LLv34_Flanker

[Yardstick]

Going back to the throttle surges. 

 

I just a flew one of the original Blitz channel map quick missions ('dogfight even' E-4s vs Hurris) and was getting the throttle surges.  As Sokol1 suggested, these seem to happen if I was close to an enemy aircraft.  As I was flying an E-4, which seems to be more resilient at full throttle 1.35 ATA, I did not blow the engine.  However, at one point following a Hurricane it got ridiculous as the in-game throttle would surge and I would back off with my physical controller, then the in-game throttle would surge again and I backed off more.  This continued for about 30 seconds, until I was flying at 50% throttle with the in-game throttle at 100% on 1.35 ATA. 

[LLv34_Flanker]

S! 

I have had this strange throttle issue too. Flew online in a 110C-4/b and had to feather(which does not work despite mapped to a button and setting to manual first) one damaged engine. The other was totally fine(No damage) but kept losing power/rpm. I added more throttle, but it simply refused to increase both manifold pressure and rpm. 

Edited August 28, 2020 by LLv34_Flanker