P-47 Roll Rate

[Ginsu80]

I am wondering if anyone is still working on the Jug? I have been reading up on WW2 P-47 tactics, notably Zemke’s Wolfpack, and they note that the Jug had excellent dive performance and a good roll rate as strengths. This doesn’t seem to match in DCS as the roll rate seems sluggish compared to all other fighters and dive performance is so so. I don’t see many changes in the patch notes, are any changes coming to the P-47?

Edited August 16, 2021 by Ginsu80

[grafspee]

1 hour ago, Ginsu80 said:

I am wondering if anyone is still working on the Jug? I have been reading up on WW2 P-47 tactics, notably Zemke’s Wolfpack, and they note that the Jug had excellent dive performance and a good roll rate as strengths. This doesn’t seem to match in DCS as the roll rate seems sluggish compared to all other fighters and dive performance is so so. I don’t see many changes in the patch notes, are any changes coming to the P-47?

 

Compare to what ?? Jug has excellent dive and good roll performance.

Pls provide some data numbers from test flights, as far as i saw it. 

Edited August 16, 2021 by grafspee

[Nealius]

I'm also curious what constitutes a "good" roll rate for WW2 fighters. When I think "good roll rate" I immediately think of the Spitfire or K4.

[grafspee]

Recent there was a topic about P-51 high alt performance, someone read somewhere that P-51 was excellent high alt fighter. So he climbed to 20-30k and he was complaining that this game sucks, his P-51 could not pull anything more the 3g at 30k but P-51 was excellent high alt fighter he said, so game is wrong  

Words like excellent, good, decent, etc means nothing, you cant input this data to the simulation.

Edited August 16, 2021 by grafspee

[Nealius]

I never said the game was wrong. I posed a question because it seemed off. Questioning something != claiming it's wrong. That's the basis of critical thinking and discourse for crying out loud. 

 

But we're obviously forbidden from questioning anything without hard data, and if we do we're automatically attacked with a straw man fallacy claiming we said something we didn't. These forums tend to offer more frustrations than solutions with the endless straw men and appeal to authority fallacies. And yet they're the only place to get information.  

 

With lack of transparency via easily accessible data that's parsed and explained for the majority of laymen players to understand without an aeronautical degree, there will be questioning based on comparisons and whatever we can find, like "excellent roll rate," because that's all we have. 

 

A problem that could be easily solved by including such flight performance data in the manuals.......like roll rate. The only time I can find performance data it's all about G or turn rate.

 

/endrant

Edited August 16, 2021 by Nealius

[grafspee]

I brought it up as similar case.

I think you can question everything. But saying "good" mean nothing until there is something you can compare to it.

I think ED posted roll rate comparison sometime ago, compare to available ww2 dcs planes it is the lowest, it was long time ago so i could miss remember that. But for it size i would say that p47 has excellent roll rate.

P-47 at the same time can have rather low average roll rate comparing to small fighters and excellent roll rate compare to similar weight planes, this is my point.

Fw-190 was one of the fastest rolling plane and if you compare p-47 to it, p-47 does not look good at all.

 

Edited August 16, 2021 by grafspee

[Nealius]

31 minutes ago, grafspee said:

But saying "good" mean nothing until there is something you can compare to it.

 

I think all the easily-sourced pilot and test pilot memoirs didn't get that memo 

[grafspee]

2 hours ago, Nealius said:

 

I think all the easily-sourced pilot and test pilot memoirs didn't get that memo 

Exactly, pilot can say that, but you cant convert it to numbers. Pilots during war encounter numerous types of enemy planes, i have never heard any pilot saying that he out climbed K-4 they only say me-109 or fw190.

Another factor is pilot it self, P-47 may be not as good in roll as Anton, but when very strong pilot rested sits in P-47 and exhausted weak pilot in Anton may change this disadvantage completely. So any this kind of pilot opinion about enemy performance may be true for specific situation, but it not represents true plane preformance.

Take for example motor sport, despite the fact that all competitors uses as identical performing cars as possible, we have winners and looser, and based on that you cant judge car performance you judged pilot performance.

Edited August 16, 2021 by grafspee

[Istari6]

Remember that most pilot memoirs discussing the P-47 Thunderbolt covered aerial combat at high altitudes (6000m+).  What we need is how did the P-47 perform at high altitudes and high speeds, compared to Bf 109s and Fw 190s?  The Spitfire is NOT a good rolling airplane once you get to higher speeds.  

[Voyager]

Finding test data on the P-47 is not easy. Fairchild destroyed everything they had on hand because they didn't have funding to declassify any of it, so, as far as I know, the only test report that exists was for a very weird scenario where they were using only 60lbs of stick force.

 

All we are left with then, short of someone contracting one of the few flight worthy planes to do a flight test cycle, are the pilot qualitative accounts and modern simulations. 

 

That said, the roll rate is going to be impacted by loadouts. 

 

What I've found is that most of the WWII air combat missions seem to have been flown with the 250 rounds per gun loading, rather than the 425 rounds per gun load. That's going to add around 450lbs of additional weight pretty far out in the wings. That's going to hurt your potential roll rate quite a bit. 

 

Also, re-reading Johnson's descriptions, he appears to be doing snap rolls, rather than plain rolls. I haven't been flying WWII era in a while so haven't experimented with it much yet. The plane does, readily, enter accelerated stalls, so I can see how a skilled pilot could use that to snap the plane at will. Definitely worth testing.

[grafspee]

7 hours ago, gortex said:

I have never, ever seen flight test data for the roll rate of a P-47.  It is not a commonly listed parameter.

It is not simply, roll rate changes with speed and alt

[Nealius]

Lots of performance data changes with speed and altitude, but is still documented. Turn rate/radius, for example. I guess roll rate was just never considered to be important enough to document? And if it isn't documented, then how does ED model it accurately?

Edited August 26, 2021 by Nealius

[Voyager]

17 hours ago, gortex said:

I have never, ever seen flight test data for the roll rate of a P-47.  It is not a commonly listed parameter.

 

Greg's Airplanes and Autos has one in his video on the P-47 maneuverability: 

 

Go to 1:03:50

 

Addendum: there was also a design change to the ailerons and linkage at some point in the P-47's development and production. I believe the effect was to trade low speed roll rate for better leverage at high speed. 

 

Oleg Maddox had posted a copy of the report on the old Il-2 forums in the 2000's but, like an idiot, I didn't keep a copy of the report, or write down what it was called. It did get incorporated into the old Il-2 game, so I'd assume copies of the report have made it into most current P-47 simulations as well. But, it may mean you will get different results from early P-47 models to later ones. 

Edited August 26, 2021 by Voyager
More data

[fapador]

ED considered moments of inertia on the roll axis FM of the p47. Thats why it feels a little sluggishcompared to  the other warbirds which they dont take account for this, So thats the reason the rest  feel a little oversensitive and overperform. Yaw and elevator on the Jug is like the rest

Edited August 26, 2021 by fapador

[grafspee]

8 hours ago, gortex said:

No duh?

No ? Because at 50mph P-47 has same roll rate as at 400mph

At very high speed P-47 experience aileron reversal which make roll rate unusable at all so yes roll rate changes with speed and alt.

Edited August 27, 2021 by grafspee

[Voyager]

15 hours ago, gortex said:

@Voyager

 

At timestamp 1:00:29 I see a data table comparing the P-48, P-47, P-51B, and P-80.  It lists 60deg/s at 400mph for the P-47.  Is that the data you're referencing?  Cool video.

At the 1:03:50 he has a chart with the roll rates of a large number of aircraft including the P-47 as a function of speed, but it's an early C model plane. 

 

The 60 degree per second at 50 lbs stick force (80 for the P-38) was the 400mph one, but it's a late war D model with unknown loadout. 

 

One of the convolutions of the P-47 is its got more travel than you can get access to at 50lbs, so a stronger pilot could, potentially get more toll out of it, but I've also heard there is a wing flex issue that may limit that as well. 

 

All in all, not a trivial thing to analyze. 

[Zunzun]

I think that part of the problem with roll rates is that there is scant sources. The most quoted test is the NACA one with roll rates measure at some specific force (50 or 60lbs?) and, as far as I remember, being steady roll (maximum or peak roll for the plane).

Most anecdotal evidence (memories from pilots) and at least in one test they praised the responsivines of the ailerons. Like this one  http://www.wwiiaircraftperformance.org/p-47/p-47c-tactical-trials.html

Also, there is a test done in the 80s that, among many other parameters, tested roll rates between different warbirds (thunderbolt, mustang, hellcat and corsair). It is obviously a test to take with a pinch of salt at best as the plane conditions weren´t the same as the war era types. But there some information that I consider could be useful to for this discussion. They compared roll rates as time to roll 180º and 360º. Even if the final times weren´t the same as the ww2 types, at least there is a comparable difference in the time rolling (same planes in two different conditions).

Rolling 360º, the p-47D is behind the other three types. But when they measure the time to 180º:

You can see that the Thunderbolt then got ahead (it completed the 180º roll quicker than ther rest). I interpret it like the p-47 can achieve its maximum rate of roll quicker than the other types despite the other have a bigger maximum rate of roll.

This, is in line with the test report above and also with some pilot memories like Robert Johnson´s one.

Could be that the p-47 was crispier into rolling and able to change direction quicker although for a sustained roll it was just average.

I know this is not compelling evidence but, at least in my opinion, has consistency and could explain the contradictory information in the matter.

 

 

 

Edited September 26, 2021 by Zunzun

[Bozon]

Why do all these planes roll quicker to the right in the 80s test? It should be the other way around - the props are turning clock-wise from the pilot’s perspective, so the engine torque is helping to roll the plane to the “left”.

edit:

There must be a printing error - the order of left/right data is reversed between the 180 and 360 deg roll tables.

Edited November 11, 2021 by Bozon

[grafspee]

1 hour ago, Bozon said:

Why do all these planes roll quicker to the right in the 80s test? It should be the other way around - the props are turning clock-wise from the pilot’s perspective, so the engine torque is helping to roll the plane to the “left”.

edit:

There must be a printing error - the order of left/right data is reversed between the 180 and 360 deg roll tables.

 

It could be the pilot who  applied  greater force on stick while doing right rolls  rolls

Edited November 11, 2021 by grafspee

[VIKBELL]

I believe that the ED group owner group has a P-47D in the stable museum that are flyable.