Propeller pitch: Auto versus manual

Ok, started to be inspired by tips and evidence about propeller pitch.

First jester wrote how to take off here:

http://forums.eagle.ru/showpost.php?p=2513323&postcount=261

Set prop pitch to 12:00, ATA 1.2 and basically let her fly off by herself.

(It works. )

Then AussieFX replied to complaints about a twitchy plane here:

http://forums.eagle.ru/showpost.php?p=2513168&postcount=162

"Auto pitch control?"

Myself trying to follow Ala13_ManOWar's advice about looping here:

http://forums.eagle.ru/showpost.php?p=2512867&postcount=16

He talks about speed, but especially of keeping the ball centered.

First attempt I made was with Propeller Auto Pitch, which I have been using the whole time:

Gave a twitchy effect, I could do it, but needed to focus on holding the plane very straight.

Also difficult to get the speed properly up.

Second attempt I did after being inspired by trying jester's fixed propeller pitch take off.

Lo and behold: Stable plane, easier to get speed up, easier to pull G's, easier to keep the plane straight, easier to keep the speed during the whole loop.

Then tried some flying with fixed propeller pitch on a little trip also.

Tried to remember the settings Kurfürst has posted several times:

http://forums.eagle.ru/showpost.php?p=2504599&postcount=96

What was the result then?:

Better speed, much easier to perform stable and coordinated turns, better fuel economy, and bonus effect: Much better trim!

Suddenly the factory trim (ED trim ) felt exactly point on!

Even at 480-500 km/h I can now fly almost without touching the stick, just a light aileron correction is needed.

Horizontal stab trim is absolutely sufficient, propeller pitch can be used to adjust this trim also.

Last piece of the puzzle:

Erich Brunotte talked about this stable and docile plane he considered the 109 to be, which some people here did not agree to.

Well, he mentioned one little detail: He preferred flying with manual propeller pitch.

When asked why, he just said, he liked feeling more control.

But could the truth of the matter be, that the plane flew better and more predictable with manual prop pitch?

To me it feels completely different, just by this little detail.

Could this in reality be some of the culprit of so much disagreement of the behaviour of the same module?

That some of us fly with Auto Prop Pitch, and some prefer to do it manually?

To all, but maybe especially those who complain about twitchy plane, and lack of trim:

Try to make some rounds with manual propeller pitch. Explore the plane.

And see if you feel same difference as me?

I shall try takeoff 1.2 ata and see how it works. I can takeoff easy under auto but landing will be the real challenge (keep scraping right wing every time)..

What was the result then?:

Better speed, much easier to perform stable and coordinated turns, better fuel economy, and bonus effect: Much better trim!

 

Suddenly the factory trim (ED trim ) felt exactly point on!

 

Even at 480-500 km/h I can now fly almost without touching the stick, just a light aileron correction is needed.

Horizontal stab trim is absolutely sufficient, propeller pitch can be used to adjust this trim also.

Do you realize you just could experience yourself how a hardcore module resembling closely the real deal behaviour needs training and know how to fly it properly? That's why I like DCS :thumbup:.

S!

Indeed,

as it is right now, the Bf109 K4 is a charm to fly, with manual or auto prop pitch.

Just came from a session edited from then default quickstart takeoff mission where I simple set the fuel to 65%, climbed to 2000m and started a series if aerobatics. Loops, rolls, barrel-rolls, stall turns, lazy eights, hammerheads, etc... It feels Amazing!

I actually didn't touch the manual trim tabs so far because the default settings feel just perfect!

I've been flying the BF-109 variants in sim's for a long time. I even flew with the good chaps at ACG and their epic battle of britain recreations. I've always flown with manual pitch control. Always. The trick most people forget is the wheel lock. When lining up on the runway, move forward about a meter or so and turn wheel lock on. This locks that back, grocery store cart, wheel that keeps the plane stable during takeoff and landing.

Takeoff: WHEEL LOCK ON! 1.2-1.4 ATA, Pitch 12:00 (unless weather, then 11:30 to push more)

Climb: 1.2 ATA, 2500 RPM, Pitch 11:00 (reduce by 0:30 for every 100kph over 200)

Climb Angle: 10 degrees up( when following above climb rules, maintains speed )

Maneuvering: RPM 2200, 1.1 ATA, Pitch 10:00

Downward Maneuver: RPM 900, 1.0 ATA, Pitch Increase

Upward: RPM 2400, 1.2 ATA, Pitch Decrease

Max for Maneuvering: RPM < 2600, ATA < 1.3 (if you let these get above those numbers, bad things happen to engine, important to keep eye on dials during maneuvers)

Landing: Pitch 12:30, RPM 900, ATA 0.8, flaps as needed to maintain 200kph and 500m on final.

Touchdown: Reduce RPM's completely, level out with a little flare to reduce your vertical speed. Land with first pair wheels, wait, wait, wait, and pull the stick back to drop the tail. Navigate with slight toe brake corrections. As soon as you are below 30kph, TURN WHEEL LOCK OFF!

Here is what Dave Southwood has to say on the manual pitch, and how it is used during displays:

http://109lair.hobbyvista.com/articles/airframes/black6/bk6_flight.htm

The pilot sets the manifold pressure with the throttle, and engine rpm is controlled either automatically (when it is governed to the running line) or manually. Manual control is by a rocker switch on the throttle and this varies the propeller blade pitch. Once set, the propeller runs with fixed pitch, RPM increasing with increasing airspeed and vice versa. Cockpit of blade pitch is on a clock. For example, 12:00 is set for take-off and 11:45 for landing. Initially, we always flew the aircraft with manual RPM control, until we were happy with the automatic control functioning. In a display, 1.15 ata is set and RPM controlled manually to 2400-2500 to prevent overboosting. This requires a setting of around 11:05 at high speeds such as for loop entries, and an increase to around 11:20 over the top of a loop. This results in a lot of head-in-cockpit time and propeller adjustment during a display, greatly increasing the workload.

Thanks for the nice and informative answers guys. :)

First of all, I will say, I have no complaints on the module whatsoever.

Like you say ManOWar, it's impressive that we can get so much out of it. :)

It might very well be that I need more training in order to handle the automatic prop pitch control.

However, I've flown with automatic until now and learned to master take off, some manoeuvring and, almost, landing.

I've not tried very much hard manoeuvring, but have been training mostly general handling and ground attacks.

Definitely need more training in dog fight.

Loops I only tried after the discussions in this thread. :)

For me it was just interesting to experience the difference in handling: Everything just seemed a bit easier when using manual propeller pitch.

About the trim:

For the automatic pitch it seems that there's a quite narrow speed/throttle area where it is completely right. And most of the time one needs to work a bit with rudder and ailerons to keep the plane straight.

When flying manual pitch, I suddenly felt that I could widen this area quite a bit. And the correction reduced itself to a little bit of aileron, which can probably be removed when I find the exact trim spot.

So, more to experiment with now. :)

First jester wrote how to take off here:

http://forums.eagle.ru/showpost.php?p=2513323&postcount=261

 

Set prop pitch to 12:00, ATA 1.2 and basically let her fly off by herself.

(It works. )

 

Second attempt I did after being inspired by trying jester's fixed propeller pitch take off.

 

Lo and behold: Stable plane, easier to get speed up, easier to pull G's, easier to keep the plane straight, easier to keep the speed during the whole loop.

 

Then tried some flying with fixed propeller pitch on a little trip also.

 

Tried to remember the settings Kurfürst has posted several times:

http://forums.eagle.ru/showpost.php?p=2504599&postcount=96

 

What was the result then?:

Better speed, much easier to perform stable and coordinated turns, better fuel economy, and bonus effect: Much better trim!

 

Suddenly the factory trim (ED trim ) felt exactly point on!

 

Even at 480-500 km/h I can now fly almost without touching the stick, just a light aileron correction is needed.

Horizontal stab trim is absolutely sufficient, propeller pitch can be used to adjust this trim also.

 

Last piece of the puzzle:

Erich Brunotte talked about this stable and docile plane he considered the 109 to be, which some people here did not agree to.

Well, he mentioned one little detail: He preferred flying with manual propeller pitch.

 

When asked why, he just said, he liked feeling more control.

 

But could the truth of the matter be, that the plane flew better and more predictable with manual prop pitch?

 

To me it feels completely different, just by this little detail.

WEOW glad I could help someone. I fly my Kurfürst with manual prop pitch for the very same reason Brunotte and several other high profile Luftwaffe pilots expressed: more control. When I fly manually, I'm able to think ahead and prepare for maneuvers and also get the most out of them.

That said, the Auto pitch control in the Kurfürst is very good. It's hundreds of times better than what we have going on in the E-4 in Cliffs of Dover. It reacts faster, changes faster and is smarter than the earlier models. But it doesn't give me the control I want over the engine.

I also fly with my radiator manually controlled. Does that blow your guys' minds? Lol

However, I've flown with automatic until now and learned to master take off, some manoeuvring and, almost, landing.

Definitely use manual pitch control for landing. When I start approach, I pull the throttle all the way back and as I slow down I increase the pitch slowly to 12:30, full fine. The trick here is to work in tandem with your engine. I do not exceed 2500 RPM for very long. So as you are preparing for your landing, chop throttle all the way to slow down to 350km/h while increasing your pitch to full fine (12:30) taking care not to overrev the engine. Lock your tailwheel if you aren't comfortable with a loose tailwheel I start to add in nose up trim as well to help me hold the sink rate without tiring my hand. As I'm coming in towards the airfield, I sometimes up the manifold pressure to .7 ATA to slow the rate I'm decreasing my speed. If I need some emergency power, I'll push it to .9 ATA which at full fine prop pitch will push the engine immediately to ~2500 RPM. At around 250km/h I drop my flaps, adjust my nose up trim accordingly and try to ride in just under 200km/h, keeping the close end of the runway level with the horizontal line on my gunsight (or front dash, if the revi is folded down). When I can't hold the the runway in my sight anymore, I pull the throttle to idle and flare gently, bringing my wings to about parallel with the ground, and then slightly angled up and away towards the nose of the aircraft. The idea here is to slow down, while dropping the last few feet of altitude in a controlled fashion.

If you've done everything correctly and Mother Nature's wind is on your side, you'll gently land on all three wheels, minimal to no bounce and start rolling out on the runway. Unlike many 109 pilots, I don't let the aircraft roll to a stop, I use my brakes. I gently and quickly stab them in alternate patterns: left, right, left, right, left, right etc.

GOOD LUCK BOYS. Welcome to the world of manually controlled 109. You're about to unlock the true power of the Messerschmitt's BF-109.

Hi Sporg.

My real world experience is with helicopters so only really taking a guess here. Really all a helicopter does is change blade pitch, but every change brings with it an upset that requires correction.

With the 109 I think it's exactly the same behaviour, so when you set the prop to manual you effectively have a constant speed prop and therefore shouldn't get those upsets. (Mustang should be the same as it's fully manual)

Now you need to be careful you don't over-torque your engine while in manual mode.

Now you need to be careful you don't over-torque your engine while in manual mode.

This is the biggest danger when flying manually. And with the Kurfürst's badass engine, it's very easy to bump the throttle and look down to see your RPM shooting past 3000.

WEOW glad I could help someone. I fly my Kurfürst with manual prop pitch for the very same reason Brunotte and several other high profile Luftwaffe pilots expressed: more control. When I fly manually, I'm able to think ahead and prepare for maneuvers and also get the most out of them.

Hehe, and thanks for that.

That was also my thought: Erich Brunotte used it because he got some better control out of it.

When I first read it, I just thought it was this sort of pedantic/skill approach "I can do it as good as the mechanics!".

But after having tested it a bit, I think it might actually be to get better and more relaxed flying out of it..

That said, the Auto pitch control in the Kurfürst is very good. It's hundreds of times better than what we have going on in the E-4 in Cliffs of Dover. It reacts faster, changes faster and is smarter than the earlier models. But it doesn't give me the control I want over the engine.

 

I also fly with my radiator manually controlled. Does that blow your guys' minds? Lol

I'm not complaining about auto pitch control.

I used it until now and will probably continue to explore its use.

Now I just got another tool in the box to try out. ;)

Actually I read in the manual posted elsewhere, that a mix of manual and auto seem to have been used:

For economy cruise manual control was recommended, in order to set the correct manifold pressure and RPM.

(how's that for the trim discussion in the other thread, guys? ;) )

Then for diving and other flying, the automatic control was recommended.

Definitely use manual pitch control for landing. When I start approach, I pull the throttle all the way back and as I slow down I increase the pitch slowly to 12:30, full fine. The trick here is to work in tandem with your engine. I do not exceed 2500 RPM for very long. So as you are preparing for your landing, chop throttle all the way to slow down to 350km/h while increasing your pitch to full fine (12:30) taking care not to overrev the engine. Lock your tailwheel if you aren't comfortable with a loose tailwheel I start to add in nose up trim as well to help me hold the sink rate without tiring my hand. As I'm coming in towards the airfield, I sometimes up the manifold pressure to .7 ATA to slow the rate I'm decreasing my speed. If I need some emergency power, I'll push it to .9 ATA which at full fine prop pitch will push the engine immediately to ~2500 RPM. At around 250km/h I drop my flaps, adjust my nose up trim accordingly and try to ride in just under 200km/h, keeping the close end of the runway level with the horizontal line on my gunsight (or front dash, if the revi is folded down). When I can't hold the the runway in my sight anymore, I pull the throttle to idle and flare gently, bringing my wings to about parallel with the ground, and then slightly angled up and away towards the nose of the aircraft. The idea here is to slow down, while dropping the last few feet of altitude in a controlled fashion.

 

If you've done everything correctly and Mother Nature's wind is on your side, you'll gently land on all three wheels, minimal to no bounce and start rolling out on the runway. Unlike many 109 pilots, I don't let the aircraft roll to a stop, I use my brakes. I gently and quickly stab them in alternate patterns: left, right, left, right, left, right etc.

 

GOOD LUCK BOYS. Welcome to the world of manually controlled 109. You're about to unlock the true power of the Messerschmitt's BF-109.

Thanks for tips. (and to others as well). :)

Actually, I performed ok landings with auto pitch also.

The reason I wrote "almost" on landings is that I need more practise on the two crucial parts:

The flare at the exact right moment, and the proper drop onto the runway, not too early stalled, and not too fast.

And then the roll-out, where I tend to not be fast enough on the rudder/brakes, so often scrape a wing on the ground before stopping. ;)

Hi Sporg.

 

My real world experience is with helicopters so only really taking a guess here. Really all a helicopter does is change blade pitch, but every change brings with it an upset that requires correction.

With the 109 I think it's exactly the same behaviour, so when you set the prop to manual you effectively have a constant speed prop and therefore shouldn't get those upsets. (Mustang should be the same as it's fully manual)

Now you need to be careful you don't over-torque your engine while in manual mode.

I was thinking exactly the same.

For the 109, both the RPM and the boost pressure changes with speed, so if you are doing advanced manoeuvring, the propeller pitch will constantly change, causing small "upsets" as you call them. :)

Actually I tried the manual pitch after finally getting comfortable with using the Mustang's manual RPM regulation, and the feel is somewhat the same in the 109 as I see it until now.

Both to you and to the others in this thread: Thank you for your constructive replies.

This was the kind of informed discussion I hoped to have on the issue. :)

The reason I wrote "almost" on landings is that I need more practise on the two crucial parts:

The flare at the exact right moment, and the proper drop onto the runway, not too early stalled, and not too fast.

And then the roll-out, where I tend to not be fast enough on the rudder/brakes, so often scrape a wing on the ground before stopping. ;)

You'll get it. Good luck out there Messerschmitt.

At normal landing power settings it doesn't make that difference if you're on manual or auto prop pitch.

Manual can at most offer additional drag from the prop if you set the blades at full fine ( 12:30 ), but that auto mechanism with the strange german name also does a great job when you pull the throttle back.

In the 109 I try to pass the rw threshold at no more than 200 km/h, preferably a bit less ( I don't stare at the ASI, just check the needle is a bit bellow the 200 mark... ), and then very gently keep pulling on the stick and trying to maintain the wings level and the aircraft aligned with the rw centerline ( cross controls can be required ).

There is a case where manual control is essential: high altitude cruise. Using auto and having the throttle lever retarded to maintain cruise rpm you will have the throttle valve not fully open, thus, reduced possible altitude.

Thx for the hint Yo-Yo, and, btw, THANKS FOR THE SUPERB Bf109 K4 we now have!

I honestly think the way control stiffness is being modeled now is second to none. Add to it the tuning on the blackouts due to G, and it's a SUPERB module, together with the 190 and the 51 :)

When will we get that Spitfire ?

At normal landing power settings it doesn't make that difference if you're on manual or auto prop pitch.

 

Manual can at most offer additional drag from the prop if you set the blades at full fine ( 12:30 )

Exactly. More drag makes it easier to slow the plane and easier to maintain speed without pushing the throttle forward and back and forward and back.

The 109 handles like a high performance sports car when you use manual prop pitch control, it's a superb aircraft to fly. :thumbup:

As I mainly fly Hurricanes and Spitfires in flight sims, its been great to give the 109 a good try, until the MK IX arrives.

Just one question for the Experten out there, what would be the recommended ATA, RPM and prop pitch settings for getting the best acceleration whilst in trimmed level flight?

This thread has had some really useful information, thanks to everyone for all the advice.

Cheers, Scream.

Here is what Dave Southwood has to say on the manual pitch, and how it is used during displays:

Amazing. I'm not too proud to admit that this is beyond me. There's already so much to do when flying aerobatics, I just don't see how these guys can do it while cooking dinner, too (so to speak).

I'm glad the 109 doesn't only have manual pitch control!

I made some tests using automatic and manual propeller pitch.

With automatic pitch I could reach around 10,5 km altitude indicated.

With manual pitch (using Yo-Yo's tip) I managed to get a bit higher:

;)

When I checked TacView, it said ~12800 m ASL. :)

This was the absolute maximum I could push her up to, without stalling out.

(PS: It might be possible to go slightly higher with auto, not sure if I pushed enough at the time.)

Great thread Sporg, thanks for the detailed explanations and testing.

You're welcome. :)

Thanks for the appreciation. :)

By the way, I tried to replicate another test I saw posted here, on the way down:

TacView said around 920 km/h TAS max. ;)

I'm not sure I performed flawlessly, but I was able to fly back to base with no apparent problems.

Propeller was set to auto pitch before the dive, and I tried to maintain medium throttle on the way down.

(Minimum throttle where the engine would pull.)

The best reason for manual pitch control is to avoid have your prop damaged in the super-coarse range that the automatic control prefers. Since you lose control over prop pitch on the first hit, better to have it in a finer position so you're not a sitting duck!

The best reason for manual pitch control is to avoid have your prop damaged in the super-coarse range that the automatic control prefers. Since you lose control over prop pitch on the first hit, better to have it in a finer position so you're not a sitting duck!

Hehe, it's one of the benefits as well, yes. :)

And if you set it according to the advice we have seen here, it looks like one can get away with having almost full maneuverability, even with only one setting of propeller pitch.

(But agree completely: Will be nice when ED get time to look at the damage model, for P-51 as well. :) )

Sorry to resurrect this question again, I'm still curious if there is an optimum setting for prop pitch that gives the greatest acceleration in trimmed level flight in the 109?

Obviously going full throttle and keeping the revs within limits are two parts of the equation, but if you don't want to lose altitude and need to gain as much speed as possible what would be the best setting for the pitch control?

Cheers, Scream.

WEP, I believe, it's the way to go if it's an escape maneuver, hence:

- Set MW50

- 1,8 ATA

- Prop Pitch set so that you read near 1800 RPM in your tachometer

Once you have reached top speed, I would reduce to 1,35 ATA and 2400 RPM ( the prop pitch lever should be set looking at the tachometer, and not at the blade pitch gauge with it's clockwork display... IMHO )...

This is how I manage to escape attacking ponies at the online dogfights :-)