P-47 is poorly represented

[BCI-Nazgul]

4 hours ago, unreasonable said:

 

This myth is immortal. It is, after all, just another version of the St. George and the Dragon myth, in turn a version of the generic "hero slays monster and gets female reward" myth, repackaged for the History Channel generation. 

 

Of course most believers identify the P-47 as George and the Dragon as the Tiger,  but given some of the comments here over the years, it would not surprise me if a few "critical thinkers" identify the Tiger as St. George. 

Kill a Tiger?  Maybe with extremely lucky shot somewhere to the top engine grate like 1 in 1000 or something.  However, many German other armored vehicles can be penetrated from a top down attack by the .50 AP round and external parts can be damaged as well (main gun barrels, tracks, periscopes, reserve fuel, external weapons, etc...)  So, it depends on your definition of "killed".   If "killed" means immediately explodes, catches fire, many of the crew killed or wounded, then the answer is no.  If killed means rendered combat ineffective either temporarily or permanently then the .50 can do that to some German armored vehicles although the Tiger is extremely unlikely to be damaged this way.   Many tanks were abandoned by the Germans not because they were not total losses, but because they weren't combat worthy and since they were usually retreating there was no way to recover them for repairs.   A broken track is as good as dead if you can't go back and fix it later.

5 hours ago, DSR_A-24 said:

I think simply by nature of the P-47's larger size we would expect it to take more punishment. Not in the sense that it is BUILT more rugged than Bf-109, but its large size grants it room to play with by enemy gun fire having less effect over a larger area. The photo of the 109 you shared has a wing area of 172.8 sq ft vs the P-47's 300 sq ft. A B-17 has a wing area 1,420 sq ft. I think it safe to assume a 1x20mm shell on a B-17 is no near is deadly as it is on a Bf-109.

Exactly.  And a larger airframe and more weight also means that the internal structure (spars, landing gear, and such) has to be built stronger/thicker to support that weight under stress.  This also improves the overall toughness of the plane.   That's the same reason you don't hunt large game with a .22 rifle and why the Germans used 30mm guns because big bombers take more damage to shoot down than fighters, so you need bigger weapons.

Edited October 16, 2021 by BCI-Nazgul

[Yak_Panther]

On 10/14/2021 at 5:53 AM, JV69badatflyski said:

Cool, another history legend coming back....
Could you provide numbers? , the one thing i remember is the "stick in concrete" when reaching the compressibility at M0.79(+/-) and the impossibility to move the plane in any direction.
In a 190 you needed 27kg stick force to retreive from a 80° dive at M0.79  . If you can provide something like that, that would be great to continue the discussion.
thank you.

The test states that the pilot of Fw-190 was not able to pull the aircraft out of dive at mach .79. The aircraft was uncontrollable until it descended 2000 meters and slowed down.  

That test is another example of the compressibility issue, which was a problem on many of the aircraft of the era. 

 

The 190 experiences the same loss of control due to compressibility as the P-47 does at nearly the same mach.

 

In both cases deflection of the stick will cause the elevator to move. However the pitching moments generated by the elevator are not enough to stop the dive, due to the increase in longitudinal stability encountered in the transonic region.  

 

Since the aircraft cannot be pulled out of a dive over the critical mach; The dive continues, the mach effects cause a rapid increase in drag.

 

The aircraft reaches terminal velocity shortly after and the dive continues.

 

As altitude decreases, the air density increases, and thus the drag force increases on the aircraft. Which causes the aircraft to slow below the critical mach. Thus reducing the compressibility effects and allowing the aircraft to be pulled out of the dive. 

This phenomenon is occurring during the 190 dive test, The 190 is only pulled from the dive after it slows below the critical mach number.

 

Which is similar to what happens in a P-47

The behavior is common to most aircraft of the era. If you look at the dive recovery section of many aircraft manuals they offer similar advice.

1. Leave the power on. The propeller adds a pitch up moment.

2.  Do not increase the trim, this will just break the wings off once the aircraft slows.

3. Maintain constant back pressure

4. The aircraft will recover suddenly at a lower altitude

Tempest:

P-47 N, which does not have a dive recovery flap:

 

The cause of the compressibility effects are summarized in various NACA documents of the era.

https://ntrs.nasa.gov/citations/19930091992

 

The NACA’s answer to the compressibility issue was the dive recovery flap. It’s not the same as an air brake, as the dive recovery flap doesn’t create enough drag to slow the aircraft considerably. On the P-47 it was noted that the flaps only reduced the velocity by 2%.

https://ntrs.nasa.gov/citations/20150019985

The primary effect of the dive recovery flap is to change the pitching moment coefficient of the aircraft.

 

 NACA RM A7F09

https://ntrs.nasa.gov/citations/19930085641

 

The aerodynamic interaction of the dive recovery flap on the aircraft. Depends on the airframe. On the P-38, the dive recovery flap has a larger effect on changing the angle of attack of the tail then on the P-47. 

 

The changing in pitching moment due to the dive recovery flap on the P-47, is primarily a result of the dive recovery flap changing the attack necessary to maintain a constant lift coefficient. 

Meaning the dive recovery flaps alter the relationship between angle of attack and lift coefficient.

 

The effect of the deploying the dive recovery flap was an almost instantaneous pitching moment.

The trim system used by the 190 and the 109 do have some advantages when it comes to compressibility. The system used by these aircraft changes the elevator's angle of attack. Similar to the interaction of dive recovery flap on the P-38. The change in elevator angle of attack may make it possible to recover from a compressibility event with a combination of trim and a constant stick force. However using max trim and pulling full aft on the flight stick can cause excessive G load leading to black outs and destruction of the wings. It seems like Messeerschmitt wanted to make it possible to pull the K-4 out of a compressibility dive without using the trim system. Flight testing of the time and the various changes to the K-4’s elevator and it’s gearing seem to indicate this too. 

 

 

[ZachariasX]

7 hours ago, Yak_Panther said:

As altitude decreases, the air density increases, and thus the drag force increases on the aircraft. Which causes the aircraft to slow below the critical mach.

Speed of sound increases some ~15% during such a dive.

[Bremspropeller]

9 hours ago, Yak_Panther said:

Since the aircraft cannot be pulled out of a dive over the critical mach; The dive continues, the mach effects cause a rapid increase in drag.

 

That's a great post you've been puitting together!

 

One thing, however, needs to be cleared up. Mach number is reliant on air temperature.

It's true that the compressibility effects include a rise in cd beyond Mcrit. As the airplane descends, it also goes down into warmer air, which in turn raises the local speed of sound, which in turn raises Mcrit and Mdd (drag-diversion Mach number), so the airplane kind of chases this Mach number all the way down, until it loses out to q (TAS and air density) and it can't reach Mcrit and Mdd at lower altitudes anymore.

 

It's probably safe to say that this Mach effect slows down the aircraft's acceleration in the earlier stages of the dive at high altitudes, until the airplane starts to be affected by raising q (due to the higher air density) and the Mach effects take a rear seat.

 

 

 

[ZachariasX]

6 hours ago, Bremspropeller said:

It's probably safe to say that this Mach effect slows down the aircraft's acceleration in the earlier stages of the dive at high altitudes, until the airplane starts to be affected by raising q (due to the higher air density) and the Mach effects take a rear seat.

Not really. Highest Mach is reached about half way into the procedure. He goes straight down at full power. There are people in this forum that would grasp for air at the idea of a late 109 not going at least 650 kmh (or much more even) in level flight on the deck, hence it is safe to assume that the decent will be fast all the way to the very end.

 

 

If you assume standard atmosphere, both 109 in the test above go to Mach ~0.76 and stabilize there before the lab rat in the cockpit does everything in his might for not getting atomized. What the test shows is mainly how great of an idea a flying tail is when you go really fast. One 109 is trimmed for a critical Mach of about 0.72 (the one on the left) with a forward trim exceeding the stated +1 deg 10ˋˋ of the K4, while the other one with more pitch up trim wants to dig in at around Mach 0.76.

 

If the poor sod in the cockpit has trimmed the aircraft such that he has to push into the dive with all his might, he stands a chance of pulling out if he pulls like an ox.

 

It is below 2000 m however that he is likely to fall below Mach 0.71, where compressiblility effects will fade and he will suddendly receive a a heavily nose up trimmed aircraft, if we assume him still going at 850 km/h TAS.

 

It is however telling that nobody dared to make the complete experiment, namely pushing the crate in a full power dive until it wants to nose over, and then just let the stick go and start with the prayers. At 850 km/h at 3000 m in a then fully sucidal 109, it takes him 4 seconds to go to 2000 m where the plane should decide to pull out of the dive as speed dropped below Mach 0.71, despite maintaining TAS. As the planes are trimmed for some ~350 km/h IAS for hands off flight (rather slow I find, but calculator says so), I‘d speculate the pitch up moment to be considerable. At 1000 m, he‘d be at Mach 0.7 if he still did 850 km/h TAS.

 

But in a nutshell, we can say that any prop aircraft under no circumstances passes much beyond critical Mach. Hence in such a power dive you, as lab rat, are always taking chances riding around critical Mach and local weather and ground level significantly affect your odds. The point of no return is at least some 12 seconds above impact.

 

Everything above applies to the P-47 except that, lacking a movable stab, you cannot adjust the point of critical Mach where the plane wants to pitch down, as elevator control fades once compressibility sets in. In the Jug, you‘re more a passenger of your current CoG.

Edited October 17, 2021 by ZachariasX

[GodTickles]

Yak has got to be the smartest guy flying the game with way to much time on his hands. I can understand what he says but I would never have the time or patients to be able to come up with all the info, much less post it. 

 

Dive speeds aside. I would like to see Yak's opinion on the durability, and flight performance of the plane in game. 

 

And one thing I did wonder, if the dev's actually did model the prop correctly. It is one thing to say it looks like the paddle prop. But a whole different thing to get the performance to match the paddle prop. I mean, they did use a completely wrong set of numbers for the ammo. Which after a lot of work on his own time, Yak was able to get them to see and admit to. 

 

People do make mistakes. It is human. It is how they react to and deal with the mistakes that I usually have issue with. In my profession, there is nobody that is harder on me for a simple mistake than myself. But I will own it, admit to it, and make damn sure I don't do it again. Good thing I am not a surgeon though. 

[Bremspropeller]

1 hour ago, ZachariasX said:

Not really. Highest Mach is reached about half way into the procedure. He goes straight down at full power.

 

I'm talking qualitative, not necessarily quantitative.

He starts at an IAS that is around 230-240km/h, which is rather slow.

If he'd start at cruise or even combat-speeds, Mach limits would be reached sooner and at higher altitudes.

 

To be pendantic: Critical Mach is where the airflow is starting to become supersonic, which can't really be trimmed by itself.

What you'd trim is the Mach number at which the dig-in starts, which I'm sure is what you mean. I think that's part of what Eric Brown hinted at when talking about "tactical Mach numbers" by which he rated the P-51 superior to both the P-47 and the P-38. He isn't really clear on it, though.

 

One thing of interest would be the loads on the jackscrew and how heavy they'd become for the pilot/ electric motor to trim.

Another point of interest would be why the Germans in both the 109 and 190, as well as the Italians with the MC 202 went for the trimmable stabilizer, while everybody else went for the adjustable tabs.

And another topic would be the role of the prop and it's drag-characteristics at high Mach. Different props will have different effects and props optimized for climb-performance might have a negative impact. So will the range of governing and the resulting AoA at RPM and the resulting blade-velocity.

 

Edited October 17, 2021 by Bremspropeller

[ZachariasX]

35 minutes ago, Bremspropeller said:

To be pendantic: Critical Mach is where the airflow is starting to become supersonic, which can't really be trimmed by itself.

Absolutely agree on that, but in the end it all comes down to (literally) to a very practical issue, namely the shift of the aerodynamic lift vector and the concominant acute loss of lift of the airfoils, wings and tail. (Unless the plane starts shedding things before that.) I think this is mostly what Eric Brown and the likes were referring to.

 

The flying tail can offset that somewhat and it made the F-86 a more usable propostition than the Mig-15 for all things really fast. And it clearly offers the 109 a possibility here that the Jug or Mustang do not have. Whether or not this was a design rationale originally in the 109 et.al., I don‘t know. But I think it is a bad idea in general diving  Bf109D or E to Mach 0.76, hence I suppose there was another rationale to use the flying tail as trim.

[Bremspropeller]

Good point.

 

2 minutes ago, ZachariasX said:

Whether or not this was a design rationale originally in the 109 et.al., I don‘t know.

 

Certainly not - the idea of compressibility as an operational constraint wasn't really there. It must have had different reasons. But which ones? ?

The tabs were probably just continued due to technological inertia with the other designers.

[357th_KW]

4 hours ago, ZachariasX said:

Not really. Highest Mach is reached about half way into the procedure. He goes straight down at full power. There are people in this forum that would grasp for air at the idea of a late 109 not going at least 650 kmh (or much more even) in level flight on the deck, hence it is safe to assume that the decent will be fast all the way to the very end.

 

 

If you assume standard atmosphere, both 109 in the test above go to Mach ~0.76 and stabilize there before the lab rat in the cockpit does everything in his might for not getting atomized. What the test shows is mainly how great of an idea a flying tail is when you go really fast. One 109 is trimmed for a critical Mach of about 0.72 (the one on the left) with a forward trim exceeding the stated +1 deg 10ˋˋ of the K4, while the other one with more pitch up trim wants to dig in at around Mach 0.76.

 

If the poor sod in the cockpit has trimmed the aircraft such that he has to push into the dive with all his might, he stands a chance of pulling out if he pulls like an ox.

 

It is below 2000 m however that he is likely to fall below Mach 0.71, where compressiblility effects will fade and he will suddendly receive a a heavily nose up trimmed aircraft, if we assume him still going at 850 km/h TAS.

 

It is however telling that nobody dared to make the complete experiment, namely pushing the crate in a full power dive until it wants to nose over, and then just let the stick go and start with the prayers. At 850 km/h at 3000 m in a then fully sucidal 109, it takes him 4 seconds to go to 2000 m where the plane should decide to pull out of the dive as speed dropped below Mach 0.71, despite maintaining TAS. As the planes are trimmed for some ~350 km/h IAS for hands off flight (rather slow I find, but calculator says so), I‘d speculate the pitch up moment to be considerable. At 1000 m, he‘d be at Mach 0.7 if he still did 850 km/h TAS.

 

But in a nutshell, we can say that any prop aircraft under no circumstances passes much beyond critical Mach. Hence in such a power dive you, as lab rat, are always taking chances riding around critical Mach and local weather and ground level significantly affect your odds. The point of no return is at least some 12 seconds above impact.

 

Everything above applies to the P-47 except that, lacking a movable stab, you cannot adjust the point of critical Mach where the plane wants to pitch down, as elevator control fades once compressibility sets in. In the Jug, you‘re more a passenger of your current CoG.

What is especially interesting in this, is that in game the 109K can wildly exceed those numbers - a while back I was able to record mach .86 @ 21,000ft, mach .87 @ 15,000ft, and mach .85 @ 10,000ft and then recover, with no real negative handling other then needing to roll in some elevator trim.  I’d bet that a number of other aircraft can exceed their limits as well.  That probably plays a huge role in players perceptions that the P-47 isn’t very good in a dive relative to its opponents.

[-332FG-SGTSAUSAGE138]

Yes a part of this is definitely the broken 109 fm. There  are few penalties if any for pushing the plane past its envelope or close to it especially with the late war planes which have very overperforming fm's. They can go super fast in dives and pull lots of pitch and they can spin and recover stupid fast. I constantly get tagged doing defensive turns against 109s that are screaming in and then instantly spin when hit and the plane cant fly. I mean its common to see 109 players spin at around 1000 ft and recover which is just silly especially in the heavier 109's. No torque at all, actually firewalling the throttle is what allows you to pull all the stupid 109 maneuvers in this game.

 

[gimpy117]

On 10/22/2021 at 10:30 PM, -332FG-SGTSAUSAGE138 said:

Yes a part of this is definitely the broken 109 fm. There  are few penalties if any for pushing the plane past its envelope or close to it especially with the late war planes which have very overperforming fm's. They can go super fast in dives and pull lots of pitch and they can spin and recover stupid fast. I constantly get tagged doing defensive turns against 109s that are screaming in and then instantly spin when hit and the plane cant fly. I mean its common to see 109 players spin at around 1000 ft and recover which is just silly especially in the heavier 109's. No torque at all, actually firewalling the throttle is what allows you to pull all the stupid 109 maneuvers in this game.

 

I remember a video with one at stall speed with full flaps pulling like 40 degree pitch ups no problem, that also coupled with planes like the Me-110 that seem to have little to no vices either at the edges of envelope. When you can beat hurricane in a low speed rolling scissors in an E series 110 you start to wonder if something is up. Meanwhile, the P-47 flies like an absolute dog. Isn't the E-series roughly similar to the P-47 or P-40 in power to weight (with a slight edge to the 110)? I say this because I have no doubts that the 110 would mop the floor with either of them. Hell, I've seen AI in a 110E do some crazy stuff after losing an entire flap from 2-3 hits from a P-38 20mm.  

Edited October 27, 2021 by gimpy117

[6./ZG26_Klaus_Mann]

7 hours ago, gimpy117 said:

Isn't the E-series roughly similar to the P-47 or P-40 in power to weight (with a slight edge to the 110)? I say this because I have no doubts that the 110 would mop the floor with either of them. Hell, I've seen AI in a 110E do some crazy stuff after losing an entire flap from 2-3 hits from a P-38 20mm.  

The Bf-110E without Armor is, for all intents and purposes, a Bf-110C. 

 

So it has about 2200hp at 6000kg, The Magic of having two Engines in the Wings energizing the inner Section and Slats outside of that. It's gonna fly like a dream on the edge of the envelope.

[gimpy117]

On 10/27/2021 at 7:04 AM, 6./ZG26_Klaus_Mann said:

The Bf-110E without Armor is, for all intents and purposes, a Bf-110C. 

 

So it has about 2200hp at 6000kg, The Magic of having two Engines in the Wings energizing the inner Section and Slats outside of that. It's gonna fly like a dream on the edge of the envelope.

so then if this is true, do all twin engine aircraft in this game have forgiving envelope edges? I genuinely curious 

[6./ZG26_Klaus_Mann]

15 hours ago, gimpy117 said:

so then if this is true, do all twin engine aircraft in this game have forgiving envelope edges? I genuinely curious 

P-38 definetly, Pe-2 can also do Cobra. They are all very stable and shouldn't be messed with. 
The A-20 is a bit less forgiving and the C-47 will definetly be a Handfull, as it was designed without Wing Twist and could be quite beastly in a stall and will spin. 

 

This behaviour is notorious and usual for a plane you would think should have been built better. 

Spoiler

 

 

[Knarley-Bob]

Try taking the P-47 up into the 'Con' trail section. Think it's a pig on the deck? You ain't seen nothin.....Thing barely flies.

[Dennis_Nedry]

I ran some high speed tests of the D28, D22, and K4 at 7000m.  This was with 150oct and the DC engine for the K4.

Rhineland Autumn map

 

D22(580 liters fuel) - 510kph IAS

D28(580 liters fuel) - 492kph IAS

K4(200 liters fuels) - 491kph IAS

 

It would be nice to be able to use the WEP until the tank ran out.  That would be more realistic as well.  It shouldn’t eat into combat power either.  Overheating should be the main concern in the 47.  Especially in  slow climb.  

Edited January 18, 2022 by Dennis_Nedry
Map

[CountZero]

51 minutes ago, Dennis_Nedry said:

I ran some high speed tests of the D28, D22, and K4 at 7000m.  This was with 150oct and the DC engine for the K4.

Rhineland Autumn map

 

D22(580 liters fuel) - 510kph IAS

D28(580 liters fuel) - 492kph IAS

K4(200 liters fuels) - 491kph IAS

 

It would be nice to be able to use the WEP until the tank ran out.  That would be more realistic as well.  It shouldn’t eat into combat power either.  Overheating should be the main concern in the 47.  Especially in  slow climb.  

On D22 tank for 7min but timer of 5min lol yes sure pilots could not use 7min in one go, they for sure stop at 5min and waited 10min!!!! to use up that other 2min they have left LOL

 

Also making WEP use eat up combat timer time on american airplanes is biggest fantasy of this arcade system compared how reality works.

Edited January 18, 2022 by CountZero

[ZachariasX]

1 hour ago, Dennis_Nedry said:

D22(580 liters fuel) - 510kph IAS

~714 km/h TAS

 

1 hour ago, Dennis_Nedry said:

D28(580 liters fuel) - 492kph IAS

~691 km/h TAS

 

1 hour ago, Dennis_Nedry said:

K4(200 liters fuels) - 491kph IAS

~689 km/h TAS

 

Not bad at all.

[Dennis_Nedry]

38 minutes ago, ZachariasX said:

~714 km/h TAS

 

~691 km/h TAS

 

~689 km/h TAS

 

Not bad at all.

I was thinking TAS was even a little bit higher than this as well but I’m not 100% tbh.

Edited January 18, 2022 by Dennis_Nedry

[ZachariasX]

2 minutes ago, Dennis_Nedry said:

I was thinking TAS was even a little bit higher than this as well but I’m not 100% tbh.

Maybe so, I just used standard athmosphere with no offset, 15°C, and 7000 m. Either way, these are fast birds.

[Dennis_Nedry]

1 hour ago, CountZero said:

On D22 tank for 7min but timer of 5min lol yes sure pilots could not use 7min in one go, they for sure stop at 5min and waited 10min!!!! to use up that other 2min they have left LOL

 

Also making WEP use eat up combat timer time on american airplanes is biggest fantasy of this arcade system compared how reality works.

I don’t have a problem with timers I just think they are too strict.

[CountZero]

3 hours ago, Dennis_Nedry said:

I don’t have a problem with timers I just think they are too strict.

well i dont know by what logic they fuiger out that if you use 5min of wep time, you are left with 10min of combat timer. If manual say wep is 5 min and combat is 15min, that means using wep is 3x more damaging to engine so how are you then left with 10min of combat, you should be left with 0 min of combat after using 5min of emergacy by their logic, or there is some manual that say that if you use wep you can just use 10min of combat after it. Also where thas it say that if you use 5min of wep you can use full 5min again after flying off wep for 10min.

 

The timers are not just to strickt they are pure fantasy.