Bf 110 cockpit, Wahlschalter and bomb load.

[robtek]

Very interesting information, Kodoss.

Thanks for that.

[Kodoss]

Added Gear and flaps button auto pop out.

What a bugged aircraft...

[Kodoss]

I added now all the bugs regarding the Bf 110 from bugtracker in the first post.

regarding the fuel selector (bugtracker#41) I will check my manual again, because I remember to have seen other lever positions. Could be from a C-1 in mine, but I will check first.

[Kodoss]

As I thought, there's something off with the fuel selector.

from the BAL-manual Feb 1940
BAL Teil 7.jpg
This should be for C-1 and C-2 series. (tank pumps)

From the "Betriebsanleitung und Rüstanleitung" June 1939. (single pump)
Bf 110 C-1 C-2 .jpg

From "BAL Teil 12" but only for D-Series I think.
Bf 110 D-0.jpg

And from the Kurz-Betriebsanleitung (KBA from Feb 40) an additional attachment from October 1942.
C-series october 42.jpg

The interresting is that in the KBA already 2 pumpsystems are mentioned.
An old one with a central pump and a new one with seperate pumps for the tanks.
The "Ersatzteilliste Teil 7" from Jan 1940 doesn't even list a single pump, only the valve switch and the tank pumps.

The only conclusion that I can see for this is, that the B-series and first and early C-1 C-2 had a single-pump. In production of early C-series the pumps-system was changed to seperate tank pumps with the valve switch.

And if you compare the valve switch system from the C-Series (C-1 C-2) with the D-Series, they also work differently. The E-series uses the same valve switch system as the D-series.

Mankau/Petrick mention in their book a change in the fuel pump system and problems with the quantity of them for the production of the D-series as a sidenote, but didn't go into detail. Maybe because of the "Dackelbauch" with 3 additional pumps, but that's only a speculation of me.

Did anyone has more info regarding this matter?

Edit: after looking more closely to the diagrams I realised that the 2. Pic shows the single pump system.
But there is still a difference between the switch position of C-series tank pumps and D-series in the drawings.

[IvanK]

Some info on the Fuel system from the Vultee engineering appraisal of a BF110C-5

[IvanK]

This is my understanding of how I think the BF110 fuel system in game should work:

BF110 FUEL SYSTEM
The BF110 has a total of 4 fuel tanks, 2 in each wing. The 2 forward tanks are FEED tanks and provide fuel to each respective engine. The Two rear tanks are TRANSFER or reserve tanks they cannot feed the engines directly (see comment on the fuel cock levers later*). The TRANSFER tanks are used to top up the FEED tanks as required.



The Fuel cocks are on the left hand side as part of the throttle quadrant. Each lever has 3 settings. In normal use they are in the " P1 u P2" position. This then causes each FEED tank to feed its respective engine. These levers also serve as Priming pumps before start by way of wobble action. More research needed specifically to understand the diff between P1 and P2 and P1 u P2 positions. These are related I believe to the position of the Fuel transfer levers on the right sill panel. (*This may also allow a direct Engine feed from a TRANSFER tank... yet to find a good reference on this. It would make sense from a combat damage control point of view)



Fuel distribution is controlled by the pilot using 2 levers mounted on the rear right Sill panel. These levers are rotated to point to the desired tank. The Front lever selects the required FEED tank. The Default or normal position is straight ahead. In this case each engine feed tank feeds its respective engine. (note this position is not presently selectable in the Sim)
The levers can be considered in a natural sense as "directional" type control. The front levers are where you want things to go and the rear levers where you want the transfer fuel to come from.

The Rear lever selects the desired TRANSFER tank and turns on its transfer pump. The centre position is the default or Normal position. In this case this results in each rear TRANSFER tank feeding its respective engine FEED tank automatically as fuel is used from the forward FEED tanks.
By using these levers the Pilot can transfer fuel from any RESERVE tank to any FEED tank.



The FEED tanks have a quantity of 375 litres each. The TRANSFER tanks have a quantity of 260 litres each.Each tank has a Lo level light set at 100 litres. Each tank quantity can be viewed by rotating the selector switch to the desired tank.




FUEL USAGE
For engine start the pilot will put each Fuel cock lever forward to the "P1 U P2" position. On the right sill panel he puts the Forward and rear transfer switches to the centre position. This allows each engine to be fed from its respective FEED tank and each TRANSFER tank to feed their respective feed tanks... keeping them topped up

In flight the pilot will simply use fuel from the 2 FEED tanks simultaneously. As soon as the Fuel level in each FEED tank drops the respective rear TRANSFER tanks will keep topping up the forward FEED tanks. I presume this is done by a Float valve arrangement in each FEED tank set at slightly below Full. The rear TRANSFER tanks will be the first to empty.When they get down to 100ltrs its respective 100 Low level light on the main panel will illuminate

Once the TRANSFER tanks are empty Engine feed is now from the remaining fuel in each FEED tank. When A FEED tank gets below 100litres its respective Low level or 100 Litre light will illuminate.

It is possible to "Cross transfer" fuel from any FEED tank directly to the other FEED tank by using the transfer switches. This might be required to minimise fuel loss following a leak etc. For example if the pilot wants to cross feed from the right FEED tank to the left FEED tank. He would have the Front lever pointing at the Front left FEED tank and the rear lever pointing at the front right FEED tank .. in a \/ arrangement.

For Fuel balancing he can also control directly which TRANSFER tank feeds a specific FEED tank. For example if the pilot wants to use the right TRANSFER tank ONLY to feed the right FEED tank he would select the forward lever to the right position.He would then rotate the rear lever to point at the "donor" right TRANSFER tank So the lever arrangement would be <
In this situation the Left FEED tank continues to feed the left engine directly. I "think" that in this condition the left TRANSFER tank is now isolated.

So by using the levers the pilot can directly control where the TRANSFER tanks transfer fuel to or isolate pretty much any tank.

When external drop tanks are carried there operation is automatic. External tanks are pressurised and feed directly into their respective FEED tank. Once a Drop tank is empty the respective FEED tank level will initially start to drop (until the normal transfer starts from the TRANSFER tanks). At this stage the pilot can jettison the now empty drop tank. There is no fuel quantity indication for the Drop tanks. Pilots would have a rough idea of end of drop tank time from the fuel consumption data. Drop tanks would always be used first.


References:
RAF PIlots notes "How to fly the BF110"
The BF110C,D,E An illustrated study by John Vascoe
The BF110C Vultee aircraft Corporation BF110C5 Exploitation document

[Kodoss]

@IvanK: mostly I agree with you, but there's one point which still is questionable.

The Fuel distribution system with its levers. Both manuals states that you can pump fuel from both reseve tanks into of of the main tanks! There's is nowhere mentioned that you can pump it directly in both main tanks. That is also shown in the diagrams that I posted before.

Here is the text from the BAL (single pump system)
BAL fuel.jpg

It states clearly

"d. Fuel distribution in the flight
Lever of the surgeside of the valveswitch can on all four, Lever on the pressureside only on both foreward tanks be switched. That means contant of all tanks can be pumped into the right or left foreward tank.
intertank transfer
1. Lever of the surgeside of the Valveswitch to the right or left rearward tank.
...
2. Lever of the pressureside of the valveswitch to the right or left foreward tank (main tanks).
3. Switch ( besides valveswitch) in position "Ein" (ON).
4. enlightens restfuel warninglamp of the drained tank, then switch to "Aus" (OFF)."

But that only counts for the early single fuel pumpsystems.

The interresting part is the text in the KBA with states both systems.
KBA Pumpventil.jpg
Last sentence on the left side:

"By mounted new fuel system(...) only the fuel of both rear tanks will be pumped simultaneously into either the left front or right front tank."
First sentence on the right side.
"Shall the content of the rear tanks be pumped in one of the front, then lever of the valveswitch to the regarding front tank and switch the pumpswitchlever (Pumpschalthebel) to position "Ein" (ON).
Drops the fuel pressure below 1,1 atü, then through moving of the switch (besides the valveswitch) to position "Ein" (ON) activate the height pumps."

That shows that the drawn positions on the diagrams are correct.
You can't select both front tanks at the same time. That counts at least for all C-1 and C-2 planes.
The D-series has another valveswitch, which is also in the E-series.
But since the C- and D-series run parallel it might be possible that later Cs also were fitted with the new valveswitch, but that's speculation.
For sure is, that in the repair yards the C-series planes were sooner or later also fitted with the same valveswitch as the D- and E-series. See the attachment of the KBA.

Edit: I can't write fast enough before the forum kicks me out...

[Kodoss]

I changed the status of the fuel distribution on the 1. post to obsolete.

http://www.il2bugtracker.com/issues/41 Fuel distribution
Might be obsolete since it's correct build in. See posts #14 and following.

I will change it back to a bug when evidence is found that D-series fuel distribution was also used in C-4 and C-7 models of this time (till end of 1940).
But for that I need the manual for the C-4/C-7, which I don't have.

[pupo162]

a litle bit of a theread hijack but you guys seem to know your 110's

http://img832.imageshack.us/img832/1216/bf110fuels.jpg

as seen in this image from IvanK

waht are those 2 big black knobs? the ones next the throttle, who look really big and important, yet they are of no use in our sim?

[Kodoss]

Those aren't knops/buttons.
Those are screws with nuts on each. This is an adjustable dead stop for the throttle. This cheap solution can be found anywhere in mechanical devices.
By old cars as an excample.