109 FM

Not quantifiable and thus not applicable. Try harder.

It's ok if you disagree, but in that case it's you I'd expect to try harder.

No disagreement per se from my part. You're just not presenting any quantifiable evidence. So please, try harder.

Well, some speeds are quoted above, so there is something quantifiable to chew on. However...

The above is absolutely nothing like the 109 we have in DCS.

... you can't say it with a straight face, when a simple flight with half fuel load reveals the DCS 109 closely follows what you quoted for the most part.

Benign stall onset in clean config with good controls authority before? Check. Actually, it's difficult to say when it begins, and it's either accompanied by no wing drop, or a very small one. There is also no noticeable nose drop, so one could say the DCS plane might be incorrectly "easier" than the real thing, thus reporting actual speeds is difficult. Still, based on variometer, somewhere about 150-ish stall speed? Check. Instant recovery by neutralizing the stick? Check. Pulling about 3.3-3.5 G when stalling around 300 kph (as reported by G-counter in F2 cam view)? Check, though this one was difficult to nail with again, very mild and smooth stall onset (buffeting noise followed by wingtip contrails) and speed dropping quickly. No noticeable handlling change when slats deploy? Check. G drops well below 3 as speed drops closer to 200, no idea how correct is that.

The only clearly different thing from the quote is behaviour with gear and flaps down, I'll agree with that. Stall onset is clearly noticeable around 130-ish with sudden drop of both nose (small) and wing (quite big - about 40 degrees). At least immediate stick-neutral-recovery works fine again.

Are you actually turning when doing these tests because I find the aircraft extremely jittery during turns and the stall quite violent with with quite the aggressive wing drop, nothing mild about it.

I find the P-51 being a lot more "mild" nd controllable when it comes to stalling characteristics, which is just wrong.

There are neglibility things that could be better, like the cockpit and the skin markings in detail, but these are only graphics.Nothing special.

To know how near the FM its on bf109, you have to ask a person who flew a bf109 and tested the bf109 DCS Simulator.

Like in this video for the fw190.

Not a Spitfire or a military jet or another plane...only the plane we are talking about. I flew a ask21 gilder and an arcus paraglider a long time ago before i became a sim couch potato.:lol:

How could i say this FM is correct... never. I can say, for me it "feels" right or wrong. But it´s just subjective, It had nothing to do with the reality.:smilewink:

I think FM discussions are bullshit and ED knows what they have to do and they do a good job.:thumbup:

I agree, the testimonies of pilots who have really flown on 109 also always include subjective rather than objective considerations that tend to distort the actual flight characteristics of an airplane.

:thumbup:

The glaring omission here on the part of any of the posters or most of the quoted anecdotes is the lack of clarification of whether the stall characteristics described are attributed to an accelerated stall or a 1g stall.

The difference is fundamental.

However the Southwood description pertains to the power off stall, test pilots routinely fly these as part of the familiarisation scheme, wings level and power off, to get a flavour of the aircrafts behavioural quirks prior to landing.

Hummingbird if you are talking about the behaviour under heavy manoeuvering, which I suspect, then all bets are off.

1. You are at full or close to full power. Ergo the gyroscopic, torque and P-factor effects will be significant and blow any gentle power-off stall characteristics out of the water.

2, Are you flying coordinated? The 109 marks benefitted from good rudder and aileron synchronicity from the pilot, particularly as directional stability - specifically at high alpha where the tailfin will be blanketed from good airflow by the wings and the aspect of the fuselage presented to the airflow - was marginal in most 109 variants.

3. How are your control curves? If you have a short throw joystick, or anything that gives an angular throw below the prototype then your small inputs will be magnified and make the tiny corrections necessary in DCS warbirds to maintain control much more difficult. This combined with the above could be making life difficult for you.

The glaring omission here on the part of any of the posters or most of the quoted anecdotes is the lack of clarification of whether the stall characteristics described are attributed to an accelerated stall or a 1g stall.

 

The difference is fundamental.

 

However the Southwood description pertains to the power off stall, test pilots routinely fly these as part of the familiarisation scheme, wings level and power off, to get a flavour of the aircrafts behavioural quirks prior to landing.

 

Hummingbird if you are talking about the behaviour under heavy manoeuvering, which I suspect, then all bets are off.

 

1. You are at full or close to full power. Ergo the gyroscopic, torque and P-factor effects will be significant and blow any gentle power-off stall characteristics out of the water.

 

2, Are you flying coordinated? The 109 marks benefitted from good rudder and aileron synchronicity from the pilot, particularly as directional stability - specifically at high alpha where the tailfin will be blanketed from good airflow by the wings and the aspect of the fuselage presented to the airflow - was marginal in most 109 variants.

 

3. How are your control curves? If you have a short throw joystick, or anything that gives an angular throw below the prototype then your small inputs will be magnified and make the tiny corrections necessary in DCS warbirds to maintain control much more difficult. This combined with the above could be making life difficult for you.

I am talking accelerated stalls as described by both Holm & Southwood (Southwood at the end), in addition to anecdotes from wartime pilots. Here the wing drop is desribed as very mild and easily dealt with. Furthermore thanks to the slats the aircraft is said to be more easily controlled on the edge of the envelope than most other WW2 fighters.

Mark Hanna also noted that the aircraft delights in being pulled into hard maneuvering turns at low speeds, and the he could pull quite hard until the whole airframe was buffeting, and that you'd have to crass to drop a wing intentionally.

http://www.eaf51.org/newweb/Documenti/Storia/Flying_%20109_ENG.pdf

All of this seems to be the complete opposite of what we have ingame where the aircraft is quite jittery and hard to control on the edge.

As a result, based on all the history that I've read, I am simply not getting the feeling that I'm flying a 109 in DCS, not even close. Feels like a completely different aircraft.

The fact that in DCS the P-51 comes very close to the 109 in turns at low speeds also to me screams that something is off, which again is also based on pilot comparisons (Holm, Hanna etc.)

In short: ED has made a lot of awesome stuff and good FMs IMO, but to me their prop job FMs are not included on that list. Maybe it's because they lack proper data, or maybe they've simply made a mistake somewhere, I dunno. But I don't fly DCS prop jobs as a result.

The trouble is Hummingbird you are using anecdotal information from warbird operators. Whilst I can't argue with their opinions on the handling they experienced, they experienced it at power levels significantly below that of typical wartime 109 pilot and ergo the typical DCS flyer in a virtual combat situation.

I've spoken to a Spitfire IX display pilot; the most they used is +6lb boost with more typical +4lb. The range of a Spitfire MP is -6 to +12 without going to WEP. Ergo there is a range of 18lb/sq.in to operate. Therefore they are flying - even at max - at 66% the capacity of the engine, with the reduced RPM settings - and therefore torque effects - that accompany them.

There is a reluctance to cane the power plants on these vintage machines as they are incredibly expensive and engine life and reliability is directly linked to how hard the engines are worked. Do you think that a Daimler-Benz 605 engined aeroplane - of the vintage aero-engines these are amongst the rarest - would be treated with any less circumspection?

Take into account that the warbird operator also flies without, ammo, armour and significantly reduced radio weight, along with sundry other survival kit items, flare chutes and the like. Ergo you have an aircraft that is significantly lighter.

Now take this reduced wing loading & reduced airframe inertia and combine that with an engine operating regime that results in reduced torque forces and reduced gyroscopic effects - is it any wonder that the aeroplane would behave differently?

The trouble is Hummingbird you are using anecdotal information from warbird operators. Whilst I can't argue with their opinions on the handling they experienced, they experienced it at power levels significantly below that of typical wartime 109 pilot and ergo the typical DCS flyer in a virtual combat situation.

 

I've spoken to a Spitfire IX display pilot; the most they used is +6lb boost with more typical +4lb. The range of a Spitfire MP is -6 to +12 without going to WEP. Ergo there is a range of 18lb/sq.in to operate. Therefore they are flying - even at max - at 66% the capacity of the engine, with the reduced RPM settings - and therefore torque effects - that accompany them.

 

There is a reluctance to cane the power plants on these vintage machines as they are incredibly expensive and engine life and reliability is directly linked to how hard the engines are worked. Do you think that a Daimler-Benz 605 engined aeroplane - of the vintage aero-engines these are amongst the rarest - would be treated with any less circumspection?

 

Take into account that the warbird operator also flies without, ammo, armour and significantly reduced radio weight, along with sundry other survival kit items, flare chutes and the like. Ergo you have an aircraft that is significantly lighter.

 

Now take this reduced wing loading & reduced airframe inertia and combine that with an engine operating regime that results in reduced torque forces and reduced gyroscopic effects - is it any wonder that the aeroplane would behave differently?

Differently in some aspects however in terms of accelerated stalls I really wouldn't expect much of a difference in behavior regardless of the engine power setting, which should only really increase the gyroscopic effect and add some extra lift with increases in power, not affect how violently the wing drops or how close to edge the aircraft can be flown, which again is as much based on period pilot accounts as modern day ones, which even agree with each other and thus rules out that the extra power should be a factor.

Also whilst the warbirds flying around today are all somewhat lighter, the 109 is probably least so considering it doesn't carry as many guns, ammunition etc as for example a P-51 or Spitfire, thus the latter two would benefit a lot more from this in any modern day comparison.

Consider also that the K-4 is one of the heaviest 109s, and pilots apparently preferred the handling/manoeuvrability of the G series (which were worse than the F in this regard as well). Try flying with full fuel and with even 70% and there is a noticeable difference in how the aircraft handles. Particularly at low speed or nose high attitude the aircraft is quite a handful.

As far as controllability on the limit I would agree that the Mustang is much tamer in DCS. At least at ~40% fuel with which I mostly fly it online. The Force Feedback gives a bit more warning which with some practice makes the P-51 very pleasant/comfortable to take right to the edge.

Here is also a good site if you want to find quotes from wartime pilots who flew or flew against 109s.

I don't fly the '109 that much, so I went to see how abrupt the accelerated stall is.

You need a FFB stick.

With a FFB stick the signals from the aircraft are obvious, and the buffeting provides such a clear indicator of an approaching stall, that you would have to (in your words) be 'crass' with the stick to stall the aircraft.

As a result, based on all the history that I've read, I am simply not getting the feeling that I'm flying a 109 in DCS, not even close. Feels like a completely different aircraft.

 

Funnily enough, based to the feelings, i have always felt that DCS 109 is closest to real thing of any of the flight sims out there.

Other sims are getting closer with latest FM updates but DCS 109 is still in top in my opinion.

I always like to read conclusions from the valued experts... Their opinions are very important for us.

 

To be serious, your last suggestion about the whole park of DCS props makes me sad and pessimistic... Dozens and dozens of joystick hours spent by Nick Grey in DCS props and dozens of hours of our discussions and consultation were in vain... Hours spent with Erich Brunotte and Klaus Plasa should have been spent more fruitfully with the right experts... Now I really understood it. And I am going to put in a waist bin thousands of archive documents pages regarding wind tunnel and flight tests, because the result does not satisfy you as a prop planes expert, so these papers are all deeply wrong.

So, I respect your decision to use any other sim you consider realistic. Finally, ending sprinkling the ashes on my head, I'd like to add a small New Year gift.

Not sure where I called myself an expert? Quite confident I never did.

No the issue is that the FM just doesn't jive with what the actual experts report. I've once before had a go at trying to give constructive criticism on another prop job as well, the Fw190, along with a fellow who actually worked on one (Crumpp), but to no avail.

Combined this is what has led me to abandon the prop jobs in DCS as I quite simply don't trust in their accuracy.

This interests me a lot, are you claiming that your current control set up is fairly accurate to what Mr Hanna would have in the aircraft he was flying? You do know and understand that even the length of the controllers we use now can make a difference, correct?

 

I can get the effect you mention, generally I have to pull back like my 5 year old is playing,

The mere fact you are getting the effect is the problem because the 109 should not depart that violently.

But if you could provide your elevator axis curves I could try them out to see if that helps?

jcomm did a good description of what seems to be causing the ingame aircraft to feel so jittery & unstable on the edge, feeling nothing like the real aircraft described by its pilots as being extremely easy to ride on the edge.

I simply find it not in harmony according to what I read from pilot reports.

 

Don't know how to put it better than saying that, in the DCS 109, slat deplyment instead of being smooth and almost unnoticeable, causes a weird separation between roll and yaw - as if there was now roll-yaw coupling, no cross-moments of inertia, a huge lack of directional stability...

 

It simply doesn't feel right, not to mention what has always been mentioned since release, being it filled or not in the MW tank....

Perhaps a mistake was made simulating the operation of the slats, I dunno, but the end result is that it just doesn't feel believable.

I dont use any special curves, but I also understand that I can pull back harder than what would be realistic, and this would effect how the aircraft feels. It's about spending time with the module, and learning not only what the realistic limitations of the 109 are, but also what effect our unrealistic stick movements are on the aircraft. Post a video, with controls displayed, we can see if you are making exaggerated moves, I would guess this is most of your issue.

Well I am using quite the S curve to prevent too aggressive column movements ingame, and the stall is happening way before I ever get close to full stick deflection.

Another odd thing about the DCS 109 is the fact that the aircraft seems to want to tighten up the turn a lot by itself, as if it features negative stability in pitch much like an F-16, which also seems quite odd.

1....the stall is happening way before I ever get close to full stick deflection.

 

2.Another odd thing about the DCS 109 is the fact that the aircraft seems to want to tighten up the turn a lot by itself, as if it features negative stability in pitch much like an F-16, which also seems quite odd.

1. That's interesting as the Army Air Forces Test from 1944 mentioned that the 109G main drawback is the large turning radius due to the lack of elevator power:

There does not seem to be sufficient backward elevator travel, even with the stick full back the control does not feel adequate.

2.The RW P-51 has the same problem if the fuselage tank is full.

So, there is no sim you can trust, as Crump, as far as I remember, was not understood and finally was permanently banned at any forum he tried to place his scientific discoveries...

This is the only place he's banned that I know of, but that's beside the point and not the reason behind my decision which is based on the feeling of the vintage prop job FMs in DCS and the fact that I don't feel we were very well listened to when trying to provide constructive feedback on them using video evidence and original documentation. Instead I felt we were attempted ridiculed & patronized in the same manner as you seem to be doing to me now pronouncing me an "expert" and singing songs etc.