Hurricane Research

[JG7_X-Man]

With the Hurri comes soon, I decided to do some research just to get a feel what we should expect to see from the Hurricane and I found some interesting information on the G-Force conversation:

 

http://www.wwiiaircraftperformance.org/hurricane/hurricane-109.pdf

 

I don't know if this is the Mk. I or Mk. II but it seems what we would expect. This on the other hand caught my eye:

 

 

[messsucher]

This is great find.

[SCG_Tzigy]

very nice find, indeed

[HR_Zunzun]

Nor that the stick forces has any influence....

 

[JG7_X-Man]

1 hour ago, HR_Zunzun said:

Nor that the stick forces has any influence....

 

 

I would think the forces acting on both aircraft control surfaces will be the same...

Edited September 28, 2020 by JG7_X-Man

[HR_Zunzun]

If the hurri can pull inside the 109 then is pulling more gs.

Can´t not dismiss the diferent Gs tolerance between different pilots (obviously that could be going the other way).

I am not denying that there is influence of the sitting position but that has been found to be not great (someone posted some study about the f16 that has a radical position compared to 109/190). On the other hand, elevator authority influence a lot the amount of Gs every plane can pull.

 

[CUJO_1970]

It’s not only the seat position, it’s also the raised leg position - these thing taken together were noted as advantages in g-tolerance by the RAF with the 109 and the US Navy in testing the FW-190 against the Corsair and Hellcat.

 

This feature is up to this point ignored in the sim.

[LukeFF]

4 hours ago, CUJO_1970 said:

This feature is up to this point ignored in the sim.

 

Because, up to this point, it's been described in general terms only. It's all good and well to say it was "a noted advantage" but an entirely another thing to say how much of an advantage it was.

[ZachariasX]

Just because a text is old doesn't mean it is any more scientifically valid than anything posted today. As long as they don't have speed, altitude and g readouts in pulling out of the dive, this means nothing except that the Hurricane has a lighter elevator than the 109 that is known to stiffen up in dives more than the others.

 

The average pilot back then had little background in physics and aerodynamics. I would say this applys to the particular pilot writing this report as well. But he will surely correlate his observations to things obvious to him, which is the seating position.

 

One should definitely take such reports with a grain of salt.

Edited October 3, 2020 by ZachariasX

[CUJO_1970]

Yes I’m sure it will continue to be ‘taken with a grain of salt’, no need to worry there.
 

I’m also pretty sure two separate Allied testing agencies independently reporting that it had a positive effect on physiology is a pretty good indicator that it did, in fact, have a positive effect on physiology. 

[Reggie_Mental]

This phenomena was well known by the Germans.

The Henschel Hs132 was a prone position dive bomber. It never got beyond the prototype stage, and this well known photo has been heavily retouched and may be completely fake. It was also considered as bomber interceptor, as it's small frontal area and likely speed would have been an advantage.

 

 

 

 

[LukeFF]

1 hour ago, CUJO_1970 said:

Yes I’m sure it will continue to be ‘taken with a grain of salt’, no need to worry there.
 

I’m also pretty sure two separate Allied testing agencies independently reporting that it had a positive effect on physiology is a pretty good indicator that it did, in fact, have a positive effect on physiology. 

 

Great! Then there must be a document out there that shows how much of an advantage it was. 

 

I mean, if someone can find an obscure radio clip where Lou Gehrig describes Ruth calling his shot, then surely there is a document out there quantifying how much of an advantage German seat design was over the Allies. And yes, I'm being entirely serious with this. 

[Barnacles]

Whilst we're on the subject of cockpit ergonomics.

 

From a report Messerschmitt Me. 109 Handling and Manoeuvrability Tests BY M. B. MORGAN, 

 

"An interesting point is that the maximum sideways force a pilot can exert on the stick is about 60 lb. on the Spitfire, but only about 40 lb. on the Me.109 ; the reason for this difference is that the cockpit of the Me.109 is so cramped that a pilot cannot bring his arm round into the position most favourable for applying a large side force to the stick."

 

If there going to model the advantageous aspects (ie increased g tolerances for slopey seats) they should model the disadvantageous aspects of various cockpits as well.

 

 

[JG7_X-Man]

2 hours ago, 71st_AH_Barnacles said:

Whilst we're on the subject of cockpit ergonomics.

 

From a report Messerschmitt Me. 109 Handling and Manoeuvrability Tests BY M. B. MORGAN, 

 

"An interesting point is that the maximum sideways force a pilot can exert on the stick is about 60 lb. on the Spitfire, but only about 40 lb. on the Me.109 ; the reason for this difference is that the cockpit of the Me.109 is so cramped that a pilot cannot bring his arm round into the position most favourable for applying a large side force to the stick."

 

If there going to model the advantageous aspects (ie increased g tolerances for slopey seats) they should model the disadvantageous aspects of various cockpits as well.

 

For a 5' 4" (1.63 m) guy like Josef "Pips" Priller, that statement would be null and void and I would argue that such a statements may have been an issue in the Luftwaffe, but not the norm. 

 

To put it in plain english, while RAF and USAAF pilots may have found the Bf 09 cramped, Luftwaffe pilots were OK with it and thus didn't ask for a larger cockpit. This is not saying that some Luftwaffe pilots found their quarters cramped by any means.

 

However, I will assure you that if there were a reduced roll rate attributable to stick deflection limits from a "cramped cockpit", that would have been solved in the 109D model that saw combat in Spain. 

Edited October 5, 2020 by JG7_X-Man

[messsucher]

7 hours ago, 71st_AH_Barnacles said:

Whilst we're on the subject of cockpit ergonomics.

 

From a report Messerschmitt Me. 109 Handling and Manoeuvrability Tests BY M. B. MORGAN, 

 

"An interesting point is that the maximum sideways force a pilot can exert on the stick is about 60 lb. on the Spitfire, but only about 40 lb. on the Me.109 ; the reason for this difference is that the cockpit of the Me.109 is so cramped that a pilot cannot bring his arm round into the position most favourable for applying a large side force to the stick."

 

If there going to model the advantageous aspects (ie increased g tolerances for slopey seats) they should model the disadvantageous aspects of various cockpits as well.

 

 

 

There was some Luftwaffe guy saying the opposite of Allied planes in the lines something like this "how they can dogfight when so much busywork in cockpit and everything is not in quick reach".

 

So I would say it was more about a matter of acquired taste than something really limiting.

[AndyJWest]

The amount of sideways force you can exert on a stick is something that can be measured. In fact, I'm fairly sure that aircraft development testing at the time sometimes involved measuring such forces. Which makes statements about it more than just about 'acquired taste'.

Edited October 5, 2020 by AndyJWest

[ZachariasX]

Funny thing is, the difference in effective seat angle is only a couple of degrees. Even the foot position is not that different. Depending on how you put in your chute and using the higher pedal positions on the Spitfire, there is also only small difference in seating position.

 

It amazes me what people make out of what is a borderline intolerable cockpit arrangement, just because they want it like that. If the Mustang had such a cockpit, you‘d require a veterinary to extract the pilot after a 7 hour mission.

[AndyJWest]

I doubt very much that any assessments made at the end of the Spanish civil war would have been able to take into account all the factors which would subsequently affect Bf 109 handling: the redesigned wing, increased power, increased weight...

 

As for the Bf 109 being a 'functional and proper killing machine', so was the Fokker Eindekker. So what?

 

 

[JG5_Schuck]

LukeFF,

Take a look at this. (https://apps.dtic.mil/dtic/tr/fulltext/u2/282780.pdf)

It would appear that a 45 degree seat angle gave you a 1/4 G advantage,

No mention of elevated leg position, (?) but if raising the legs to a similar angle gives a similar advantage, i would surmise a 1/2 G advantage would be gained.

I have no idea as to the angle of German seats or the leg elevation though...

Still an interesting read..

Hope this helps in some way.

[messsucher]

1 minute ago, AndyJWest said:

I doubt very much that any assessments made at the end of the Spanish civil war would have been able to take into account all the factors which would subsequently affect Bf 109 handling: the redesigned wing, increased power, increased weight...

 

As for the Bf 109 being a 'functional and proper killing machine', so was the Fokker Eindekker. So what?

 

 

 

Listen. Bf 109 was German engineering, which at the time being was world class engineering. They would had scrapped the whole concept during the first prototypes if they found the cockpit being too cramped so that the pilot can't fly the plane up to its performance. The plane was so successful it ended up being the fighter dropping down enemy planes more than any other fighter. To say 109 was bad is just delusional.

[AndyJWest]

1 minute ago, messsucher said:

 

Listen. Bf 109 was German engineering, which at the time being was world class engineering. They would had scrapped the whole concept during the first prototypes if they found the cockpit being too cramped so that the pilot can't fly the plane up to its performance. The plane was so successful it ended up being the fighter dropping down enemy planes more than any other fighter. To say 109 was bad is just delusional.

 

I suggest in future you spend more time reading what people have actually written before posting made-up-bollocks about 'delusional' things they never said, if you want anyone to take any notice of you. I won't, because you are now going on my ignore list. 

[messsucher]

1 minute ago, AndyJWest said:

 

I suggest in future you spend more time reading what people have actually written before posting made-up-bollocks about 'delusional' things they never said, if you want anyone to take any notice of you. I won't, because you are now going on my ignore list. 

 

My apologies of that if you took it personal. I however stand by on concrete evidence. Bf 109 was a superior fighter.

[HR_Zunzun]

7 minutes ago, messsucher said:

 

Listen. Bf 109 was German engineering, which at the time being was world class engineering. They would had scrapped the whole concept during the first prototypes if they found the cockpit being too cramped so that the pilot can't fly the plane up to its performance. The plane was so successful it ended up being the fighter dropping down enemy planes more than any other fighter. To say 109 was bad is just delusional.

And still the cockpit was cramped and the arm leverage was limited (as this report suggested).

That the 109 had limitations like any other fighter doesn´t imply that his performance as a whole was bad. If you have limitations in lateral control you may overcome them changing your tactics. It seemed that this was what the 109 pilots did.

Now, trying to imply that a plane had some measureable performance characteristics better than those objetive measures indicated only because his operational record was very good it is what I would risk to consider delusionally biased.

Edited October 5, 2020 by HR_Zunzun

[Barnacles]

6 hours ago, JG7_X-Man said:

 

 

However, I will assure you that if there were a reduced roll rate attributable to stick deflection limits from a "cramped cockpit", that would have been solved in the 109D model that saw combat in Spain. 

This was an E model they tested.

 

And it wasn't subjective either. They actually measured it.

 

Of course there's a lot of whataboutery that can render this 'null and void' like average pilot's height, techniques to mitigate etc. But this whataboutery can equally be applied to the German planes' slopey seat.

[messsucher]

5 minutes ago, HR_Zunzun said:

And still the cockpit was cramped and the arm leverage was limited (as this report suggested).

That the 109 had limitations like any other fighter doesn´t imply that his performance as a whole was bad. If you have limitations in lateral control you may overcome them changing your tactics. It seemed that this was what the 109 pilots did.

Now, trying to imply that a plane had some measureable performance characteristics better than those objetive measures indicated only because his operational record was very good it is what I would risk to consider delusionally biased.

 

I have read that actual bf 109 pilots were very fond of the plane, they tend to praise it a lot. Never read someone bitching about cramped cockpit. So what I have is opinions of real bf 109 pilots and statistics. What you have? One report of some nobody allied test pilot? You can try cancel history, but you are not doing a favor for WW2 flight simulator world by doing that.

 

 

[Barnacles]

My point isn't that the recliner seat in the 109 wouldn't give an advantage (however slight), all things being equal, in terms of g tolerance. I'm actually certain it would.

 

But rather if you're going to incorporate effect of minutia in the FM, you shouldn't just cherry pick the marginal gains that only give a positive improvement to your pet plane.

4 minutes ago, messsucher said:

 

I have read that actual bf 109 pilots were very fond of the plane, they tend to praise it a lot. Never read someone bitching about cramped cockpit. So what I have is opinions of real bf 109 pilots and statistics. What you have? One report of some nobody allied test pilot? You can try cancel history, but you are not doing a favor for WW2 flight simulator world by doing that.

 

 

10/10 top trolling. But you're rumbled now. Whose smurf account is this?

Edited October 5, 2020 by 71st_AH_Barnacles

[messsucher]

7 minutes ago, 71st_AH_Barnacles said:

My point isn't that the recliner seat in the 109 wouldn't give an advantage (however slight), all things being equal, in terms of g tolerance. I'm actually certain it would.

 

But rather if you're going to incorporate effect of minutia in the FM, you shouldn't just cherry pick the marginal gains that only give a positive improvement to your pet plane.

10/10 top trolling. But you're rumbled now. Whose smurf account is this?

 

Ah, superior evidence left you without without words other than insults. It is fine. You have all the rights to live in your alternative reality, and ignore the facts that Bf 109 was actually a proper killing machine, that it was for Luftwaffe what T-34 was for Red Army.

[LukeFF]

34 minutes ago, messsucher said:

I have read that actual bf 109 pilots were very fond of the plane, they tend to praise it a lot. Never read someone bitching about cramped cockpit. So what I have is opinions of real bf 109 pilots and statistics. What you have? One report of some nobody allied test pilot? You can try cancel history, but you are not doing a favor for WW2 flight simulator world by doing that.

 

You really should do some more reading, then, instead of throwing around general quotes about how "the 109 was great, and because it was so awesome, the cockpit was not cramped."

 

Here, let me help:

 

Quote

The cockpit was cramped and the visibility wasn't good. This was evident when landing in bad conditions, especially with the G-2's cabin. This was evident when landing while it was snowing and the landing field was covered with pure white snow.
- Aulis Rosenlöf, Finnish fighter pilot.

 

Quote

"Other factors affecting the '109 as a combat plane include the small cramped cockpit. This is quite a tiring working environment, although the view out (in flight) is better than you might expect; the profusion of canopy struts is not particularly a problem.  In addition to the above the small cockpit makes you feel more a part of the aeroplane."
- Mark Hanna of the Old Flying Machine Company flying the OFMC Messerschmitt Bf 109 G (Spanish version)

 

Quote

"The cockpit arrangements were good, though close-fitting to a large man."
-Mikko Lallukka, Finnish fighter pilot.

 

Quote

Was it a tight fit?
"You got used to it. Both shoulders were against wall, which didn't help when you had to look all around in a battle. But we weren't wearing too much either."

- Mauno Fräntilä, Finnish fighter ace. 5 1/2 victories.

 

Quote

"The straps weren't so tight you couldn't move. Sometimes a lot. "
- Mauno Fräntilä, Finnish fighter ace. 5 1/2 victories.

 

All from:

http://www.virtualpilots.fi/feature/articles/109myths/

 

Quote

The cockpit was small and narrow, and was enclosed by a cumbersome hood that was difficult to open from the inside and incorporated rather primitive sliding side panels...space was so confined that movement of the head was difficult even for a pilot of my limited stature.

-Eric Brown, speaking about the G-6

 

Edited October 5, 2020 by LukeFF

[AndyJWest]

I suspect that Willi Messerschmitt may well deserve to be added to the number of people who thought that the Bf 109 cockpit was too cramped. He seems to have taken the opportunity to incorporate a larger one into his Me 309 design concepts.

 

For its time, the Bf 109 was a brilliant example of minimalist engineering. Like all real-world designs though, it had to make compromises. Some of which, by the end of its over-extended lifetime, had proven problematic. Amongst the Allies, Hawker's for example (remember them - wasn't this thread about one of theirs?) had the opportunity to learn lessons, and build new aircraft designs based around what they had learned. The German aircraft designers didn't. Or not in the numbers that really mattered, once they had settled on the Bf-109 replacement that never entirely was, the Fw 190. The extent to which the Fw 190s roomier cockpit was a deliberate choice rather than the consequence of designing around a bulkier engine is probably open to question, but I doubt very much that Kurt Tank would have seen lack of elbow room (literally) as an asset to be emulated. 

[JG7_X-Man]

11 hours ago, 71st_AH_Barnacles said:

This was an E model they tested.

 

And it wasn't subjective either. They actually measured it.

 

I am not sure anyone is disputing the known fact that the Me 109s cockpit was cramped.

However, I am disputing it was cramped to the point of a "Luftwaffe" pilot (that trained and fought in the aircraft) could not fully deflect the joystick in any direction which would impede the designed performance of the aircraft.

 

@71st_AH_BarnaclesSince the D model (which was used in Spain) had the same cockpit as the E model, which was tested, any stick deflection issues found in the "D" model would have been corrected in the "E" model. However, this was not the case. Thus, be it [Me 109] cramped to M. B. MORGAN's acceptable standards, is was adequate for those that spent several more hours training and fighting in it. Since I had to spell it out to you - this is what you call "Deductive logic".

[Mitthrawnuruodo]

This argument about the cramped cockpit is pointless. Control lockup due to stick forces at high speeds is modeled in the game. If evidence shows that the 109 aileron control is overperforming, it could be reported as a flaw.

 

Besides, arguments of the type “X shouldn’t be modeled correctly because unrelated mechanic Y isn’t modeled correctly” are very weak.

 

However, I don't know how to translate the data from tilting seat tests into something that can be applied to the relatively subtle variations in fighter seat and leg positions.

[Barnacles]

45 minutes ago, JG7_X-Man said:

 

However, I am disputing it was cramped to the point of a "Luftwaffe" pilot (that trained and fought in the aircraft) could not fully deflect the joystick in any direction

 

@71st_AH_Barnacles

That's not what the report says. You're making some sort of conclusion here which is erroneous. I'm not sure how, but less force =/= less movement, because the resistive (ie Newtonian equal and opposite reaction) is proportional airspeed.

 

If the airspeed is low enough you can move all the way to max deflection, just that if you get a stronger pilot,/bigger cockpit/ pilot with better technique that speed will be higher.

3 minutes ago, Mitthrawnuruodo said:

This argument about the cramped cockpit is pointless. Control lockup due to stick forces at high speeds is modeled in the game. If evidence shows that the 109 aileron control is overperforming, it could be reported as a flaw.

 

Besides, arguments of the type “X shouldn’t be modeled correctly because unrelated mechanic Y isn’t modeled correctly” are very weak.

 

However, I don't know how to translate the data from tilting seat tests into something that can be applied to the relatively subtle variations in fighter seat and leg positions.

No it's not because the game models stick forces, and they are constant across each plane. The virtual pilot exerts the same maximum no matter what plane he's in. If you go into the FM and reduce that value it'll have a corresponding effect on roll rate, across all aircraft.

7 minutes ago, Mitthrawnuruodo said:

 

 

Besides, arguments of the type “X shouldn’t be modeled correctly because unrelated mechanic Y isn’t modeled correctly” are very weak.

 

 

It's not really unrelated. Op says: because of the geometry of plane X's cockpit Vs Y's cockpit, there should be a difference between the physiology in the two planes pilots.

 

My point, is pretty much exactly the same. (Although I brought it up, I don't think such minutiae would be worth modelling, I'm just demonstrating that if you go down this route, it's only valuable if you take the good points AND the bad points of the respective designs, otherwise you're cherry picking.

[Mitthrawnuruodo]

21 hours ago, 71st_AH_Barnacles said:

No it's not because the game models stick forces, and they are constant across each plane. The virtual pilot exerts the same maximum no matter what plane he's in. If you go into the FM and reduce that value it'll have a corresponding effect on roll rate, across all aircraft.

 

I'll admit that I have no idea how the control deflections are calculated under the hood. Are the dynamics of surfaces and linkages modeled from first principles, or is it based on parameter fitting to performance data (or estimates)?

 

21 hours ago, 71st_AH_Barnacles said:

My point, is pretty much exactly the same. (Although I brought it up, I don't think such minutiae would be worth modelling, I'm just demonstrating that if you go down this route, it's only valuable if you take the good points AND the bad points of the respective designs, otherwise you're cherry picking.

 

I think that it’s better to model one aspect accurately even if another is ignored, as the overall accuracy of the simulation is increased. We could argue against improvements forever by invoking something else that isn't modeled. Some degree of cherry-picking is intrinsic to this game.

 

That said, I'm not convinced the seating position effects are significant enough to be worth the development effort, especially when all the variations in 50+ aircraft are examined. However, it's still interesting to explore.

Edited October 6, 2020 by Mitthrawnuruodo

[Barnacles]

7 minutes ago, Mitthrawnuruodo said:

 

I'll admit that I have no idea how the control deflections are calculated under the hood. Are the dynamics of surfaces and linkages modeled from first principles, or is it based on parameter fitting to performance data (or estimates)?

 

 

I think that it’s better to model one aspect accurately even if another is ignored, as the overall accuracy of the simulation is increased. We could argue against improvements forever by invoking something else that isn't modeled. Some degree of cherry-picking is intrinsic to this game.

 

That said, I'm not convinced the seating position effects are significant enough to be worth the development effort, especially when all the variations in 50+ aircraft are examined. However, it's still interesting to explore.

I think it's a case of in game they certainly have stated that their data for roll rate is for a given stick force: this was in response to queries about the lagg 3 roll rate. I could be wrong though as this was years ago.

 

As far as I am concerned, if there really was a massive advantage with the seat position, I'd want it to be modelled, but looking at the drawings, there really is not that much significant difference between the different planes.

 

It's like the bouncing 50 Cals of the ground to destroy tanks thing, it was actual ww2 veterans saying that it was so, but there's no science that I'm aware of to back it up. 

 

Also with the stick forces and the g loc, there are so many other factors that the advantages conferred by a couple of degrees are statistically insignificant.

 

Looking at drawings with a protractor overlayed

 

 Bf-109F-G: 13 degrees

Fw-190D  : 18 degrees

P-51D       : 18 degrees

Spitfire      : 13 degrees

Hurricane  : 18 degrees
  
Is the angle of the seat back to the gun boresight

[JG5_Schuck]

1 hour ago, 71st_AH_Barnacles said:

 

Looking at drawings with a protractor overlayed

 

 Bf-109F-G: 13 degrees

Fw-190D  : 18 degrees

P-51D       : 18 degrees

Spitfire      : 13 degrees

Hurricane  : 18 degrees
  
Is the angle of the seat back to the gun boresight

 

The seat back position itself was not the all important feature, but also the leg position.

Lifting the legs higher, and closer to the horizontal makes it easier for the heart to pump the blood against the G forces and to stop it from pooling at the extremities.

Just check out a modern F1 driver seating position it allows them to handle up to 6.5 lateral G.

I would be interested to know how much say a 1/4G increase would actually help in game. (something the devs/testers could try out, maybe?)

Surely any advantage is an advantage no matter how small!

[ZachariasX]

11 minutes ago, JG5_Schuck said:

The seat back position itself was not the all important feature, but also the leg position.

You don‘t have your feet much lower in a Mustang. Or if you use the higher footrest in the Spit.

 

There is just no way to get reproducible differences in g tolerance from such subtle differences in seating positions. And there is zero data on such supporting any quantifyable differences besides the wishful thinking here.

[JG7_X-Man]

18 minutes ago, JG5_Schuck said:

The seat back position itself was not the all important feature, but also the leg position.

Lifting the legs higher, and closer to the horizontal makes it easier for the heart to pump the blood against the G forces and to stop it from pooling at the extremities.

Just check out a modern F1 driver seating position it allows them to handle up to 6.5 lateral G.

I would be interested to know how much say a 1/4G increase would actually help in game. (something the devs/testers could try out, maybe?)

Surely any advantage is an advantage no matter how small!

Exactly!

These are all rough drawings to slow what @JG5_Schuck is explaining.

 

If we are going to simulate G-Loc and provide an advantage to "ALL" US aircraft that flew in '44 with the assumption that everyone wore a G-suit, there should also be an advantage for the pilot's sitting position as the German aeronautical engineers also developed this for the same reason, to prolong the onset of G-Loc. If we are selling authenticity, this should be factored into the pilot's physio.

 

[messsucher]

G force things are a biggie. G suits are a fact, but how much they helped during WW2 is another question.

[Barnacles]

17 minutes ago, JG7_X-Man said:

Exactly!

These are all rough drawings to slow what @JG5_Schuck is explaining.

 

If we are going to simulate G-Loc and provide an advantage to "ALL" US aircraft that flew in '44 with the assumption that everyone wore a G-suit, there should also be an advantage for the pilot's sitting position as the German aeronautical engineers also developed this for the same reason, to prolong the onset of G-Loc. If we are selling authenticity, this should be factored into the pilot's physio.

 

Ok. A good starter for 10 will be to determine whether there's a quantifiable difference in the seating positions of the aircraft in question. As far as backrest angle is concerned the spit and 109 are 13 degrees and the d9, p51 and hurricane are 18 degrees.

 

And for the leg position, if the higher footrests are used, the hurricane seems pretty similar to the 109.

Now we might be able to measure this exactly. Maybe we could ask 1c as to what shoe size their virtual pilot is, inside leg measurements, whether they dress to the right or left etc?

[JG7_X-Man]

Moving on.

Edited October 7, 2020 by JG7_X-Man