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gavagai
Mar-29-2014, 14:12
So I am way out of practice with Clod (was I ever in practice?). 109 engine management is very tricky for me compared to the Hurricane and Spit. What gives me trouble is managing the propeller pitch. With the Hurri and Spit it's easy because you set your desired RPM and you're good. With the 109E-3 it's a constant hassle to manage the pitch in a dogfight. How do some of you set up your controls for the 109E-3? Do any of you set your throttle axis to the pitch and manage the manifold pressure with something else? I tried the 1 minute emergency power setting earlier today and the engine blew up in 10 seconds, ugh.:ind:

ZG15_robtek
Mar-29-2014, 14:23
Best is to have a button for increasing rpm and a button for decreasing rpm.
Ideally positioned at your throttle in reach of the thumb as you are constantly using them.
For blowing up your engine watch not only your rpms but also the ata, constantly.
I believe the cooling system of the 109 is still porked, as i never get below 85 degree water temp even with 350 km/h, 0,7 ata at 6000 m with 1500 rpm and coolerflaps full open.
In this constellation the 109 should be able to fly with cooling flaps fully closed!!!
One is never in danger of overcooling ones engine, which was a real danger in RL.

9./JG52_J-HAT
Mar-29-2014, 15:22
Yup, two buttons for pitch up and down is easiest for me. I just got used to, dive, push it, climb, pull it on my throttle index finger. After a while you will inow how much holding it pressed is necessary in diferent situations. Engine sound helps too.
I also use the "glance at cockpit" control to look at the gauges without moving my head, just my eyes.

Regarding the cooling model, we've had a post about this a while ago. CloD only models closed, pressurized systems (like the British planes use). The 109 had an unpressurized system, which made the temperature limits decrease with altitude. There is also no undercooling modelled. So you can dive at 700 km/h with full rads open and no throttle and nothing will happen.

Gladio
Mar-29-2014, 15:34
Hi Gava, long time. I use the the Saitek Throttle Quadrant but having the TrackIR sometime I prefer to use the stick's hat switch

III./ZG76_Saipan
Mar-29-2014, 15:39
I use a button on my x52 the pitch, in combat you have to listen to the eng. to adjust accordingly...takes time but worth it.

gavagai
Mar-29-2014, 18:38
For blowing up your engine watch not only your rpms but also the ata, constantly.


That is good advice, but I've never seen the ata go above 1.3 without war emergency power.

Thanks for the comments. I will keep practicing. I fully admit this is user error here.

VO101_Kurfurst
Apr-01-2014, 03:43
Regarding the cooling model, we've had a post about this a while ago. CloD only models closed, pressurized systems (like the British planes use). The 109 had an unpressurized system, which made the temperature limits decrease with altitude.

NOPE.

I am not sure where this nonsense originates from but it gets circulated accross the board. So lets make it clear: the DB 601A has a closed, pressurized cooling system, operating at 0,75 atü (ü= überdruck, or "overpressure", meaning that the coolant pressure is 0,75 atm above ambient pressure.

The British may or may not have been using higher pressures in their coolant, but increasing pressure only serves better cooling contact and, increases slightly the boiling point of the coolant agent. Increasing pressure yields dwindling gains, so there is not much point about it above a certain point. The Brits, at least with early Merlins iirc used a high proportion (or was it pure?) glykol as coolant, which has much higher boiling temperatures, but also much less ability to carry away heat, than water.

http://www.kentchemistry.com/links/GasLaws/Boilin19.jpg

See the scanned page next to "further increasing revs" section. http://kurfurst.org/Engine/DB60x/DB601_datasheets_A1.html

http://kurfurst.org/Engine/DB60x/datasheets/601a1_MttAG.jpg

"9. Coolant system: Closed (max. 0.75 atü) coolant cross-circulation with coolant tank in the main or aux. electric circuit"

Trials with the 109E-1 prototype also showed that the aircraft could maintain constant 90 degrees Celsius coolant temperature with the radiator flaps 1/4 open (ie. streamlined position) and constant 62/82 degrees Celsius oil temperature with the oil flap closed.

http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html

9./JG52_J-HAT
Apr-01-2014, 05:32
Hi Kurfurst,

thanks for the info.

But why does the plane manual states differenty then?

http://109lair.hobbyvista.com/techref/manuals/bf109e.pdf

8727

If it's a pressurized system, the temperature shouldn't drop like that with altitude. If the pressure is the same, boiling point stays constant. Max allowed temperature shouldn't drop like that.

But you are the 109 expert, not me (no sarcasm intended) so I trust your judgement. But do you know why it is like that in the manual?

gavagai
Apr-01-2014, 06:22
Wow, look at the iupac names. Who on earth calls it ethanoic acid?

but thanks for the info!:thumbsup:

ZG15_robtek
Apr-01-2014, 06:34
If the limit for the 109 coolant pressure is 0,75 atü is regarding ambient pressure,
then the overall pressure would be lower at great heights, and so the boiling point lower.

9./JG52_J-HAT
Apr-01-2014, 11:10
That's what I thought. 0,75 atü would be just the setting for the pressure relief valve. At 10km, with an external pressure of about 0,26 bar, the valve would open at ~1 bar. If the system is pressurized at 1 bar, you would be really flying at the limit there.

9./JG52 Ziegler
Apr-01-2014, 11:25
Wow, look at the iupac names. Who on earth calls it ethanoic acid?

but thanks for the info!:thumbsup:

:) You'll get the hang of it pretty quickly. I never use the auto pitch (on the E4's) since they cannot quite keep up and you can still over rev it and pooch the engine with autopitch on. You'll get better performance with manual control too.

My rule of thumb is as long as my airspeed is 350kph or higher and revs are 2300 or less, you will almost never blow the engine regardless of ata. That's with the rad cinched up fairly tight too (40% oil and a full turn closed from 100% open coolant). Airspeed and revs are the biggies. Drop below 350 and you'll need to watch carefully at high ata. I keep the cursor on or close to the coolant temp gauge so that I can move my head slightly and get a quick reading. :thumbsup:

hnbdgr
Apr-11-2014, 09:18
Hi Kurfurst,

thanks for the info.

But why does the plane manual states differenty then?

http://109lair.hobbyvista.com/techref/manuals/bf109e.pdf

8727

If it's a pressurized system, the temperature shouldn't drop like that with altitude. If the pressure is the same, boiling point stays constant. Max allowed temperature shouldn't drop like that.

But you are the 109 expert, not me (no sarcasm intended) so I trust your judgement. But do you know why it is like that in the manual?

I'm genuinely interested in this topic, this raises a lot of questions:

Here's the first one about an unpressurized system in RL - if the boiling point is reached sooner with higher altitude - does the pilot have to fly more carefully and is this even possible? How would you keep under 82C @ 8KM
In a real life scenario would it mean the 109 would not be able to climb at recommended settings? What I'm trying to get at is - would the engine temperature fall anyway at that height (cooler air?physics:D?) or not. The other thing to consider is whether the 109 engines operated within 85-100C range in RL or was the range largel? e.g. like 75-100. Because as stated above in game we can't go below 85.


My second question touching on a previous post is about ATA. Is ATA a product of the throttle(fuel intake) and WEP(same thing) or does prop pitch play any role here whatsoever. If I was flying at 1.3 ATA and let my prop pitch drop to maintain 1,800 RPM would it affect the ATA? Also would ATA change with different height? The reason why I'm asking is that I never noticed the the engine blow due to ATA. It stays at 1.3 at full power and goes to 1.4 at WEP and that's it - I don't look at it often, because i know it's the RPM(and prop pitch) that is important to good CEM for me.

EDIT: I'll just add that even at full throttle @ 2300 RPM, I can sustain a 250kmh climb pretty much ad infinitum including the 3-4km range where it's usually heating up super fast

I hope it makes sense... if not do tell me:D
many thanks!

hnbdgr
Apr-15-2014, 04:58
anyone?

varrattu
Apr-15-2014, 10:14
Hi hnbdgr,

this article covers the primary systems found on most aircraft:

Aircraft Systems (http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2006.pdf)

:salute: ~V~

hnbdgr
Apr-15-2014, 10:24
Hi hnbdgr,

this article covers the primary systems found on most aircraft:

Aircraft Systems (http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2006.pdf)

:salute: ~V~

thank you I'll have a look!