Tempest V performance - Winter 1944

[Talisman]

Very informative read regarding the Tempest here: 
https://www.amazon.co.uk/Tempest-Over-Europe-Roland-Beaumont/dp/1853104523
  
Note that the author states that 150 grade Octane fuel and 416 mph ASI at sea level gave Tempest pilots the edge and confident advantage in the hard-fighting winter of 1944. 
This is more proof that we should have historically accurate 150 Octane fuel and the resulting Tempest V performance to help counter the Me 262 which is historically included for the Axis in the upcoming BoPB.  
Lets hope that Allied technical advances are included in BoBP as they are for the Axis. 
Also of interest, is the demonstrating of the Tempest V to VIP audiences, including visiting Russian generals on 30th August 1944.  Can any beta testers replicate this? 

Practical dive limit of 545 mph and fully manoeuvrable looks good too!
 

Happy landings,

 

Talisman

 

Edited September 23, 2019 by 56RAF_Talisman

[ICDP]

That is not a first hand report and any that I find for +11lb Tempest do not get 416 as SL and on average were about 20mph slower than that claim.  I do agree 150 grade fuel should be an option.

 

Taken from WWII Aircraft performance (Mike Williams).

http://www.wwiiaircraftperformance.org/tempest/tempest-V.html

 

 

(Text from same site)

All the Tempests charted above were equipped with Sabre IIA engines. Adjusted to reflect +9 lbs., JN.731's top speed is 378 mph at sea level and 432 mph at 18,000 feet. JN.798 was equipped with Mark V cannon, its top speed being 378 mph at sea level and 436 mph at 18,400 feet. Trials of JN.798 using 150 grade fuel and +12 lbs boost 3,700 rpm resulted in 394 mph at sea level. JN.763 was tested by RAE, Farnborough using 150 grade fuel, resulting in 393 mph at sea level at +10.5 lbs 3,700 rpm. The RAE estimated 398 mph at sea level for JN.763 at +11 lbs. RAE further concluded that had JN.763's poor paintwork on the wing leading edges been cleaned up, sea level speed would increase to 404 mph.

[JG7_X-Man]

34 minutes ago, 56RAF_Talisman said:

...Lets hope that Allied technical advances are included in BoBP as they are for the Axis. 

 

...I agree, but only where they have been validated! Can't be making stuff up or going with "I think", or 'I feel" - we need hard facts backed by verifiable data. 

[Talisman]

6 minutes ago, ICDP said:

That is not a first hand report and any that I find for +11lb Tempest do not get 416 as SL and on average were about 20mph slower than that claim.  I do agree 150 grade fuel should be an option.

 

Taken from WWII Aircraft performance (Mike Williams).

http://www.wwiiaircraftperformance.org/tempest/tempest-V.html

 

 

(Text from same site)

All the Tempests charted above were equipped with Sabre IIA engines. Adjusted to reflect +9 lbs., JN.731's top speed is 378 mph at sea level and 432 mph at 18,000 feet. JN.798 was equipped with Mark V cannon, its top speed being 378 mph at sea level and 436 mph at 18,400 feet. Trials of JN.798 using 150 grade fuel and +12 lbs boost 3,700 rpm resulted in 394 mph at sea level. JN.763 was tested by RAE, Farnborough using 150 grade fuel, resulting in 393 mph at sea level at +10.5 lbs 3,700 rpm. The RAE estimated 398 mph at sea level for JN.763 at +11 lbs. RAE further concluded that had JN.763's poor paintwork on the wing leading edges been cleaned up, sea level speed would increase to 404 mph.

If I read correctly, these trials are dated May 1944.  The author is talking of the hard-fighting winter of 1944 and also mentions displaying 'RB' JN751 on 30th August.  I suggest that May 1944 test figure performances would have been much improved on by the necessity of fighting a war and the continuing improvements being made to engines and fuel, etc.

 

Happy landings,

 

Talisman

5 minutes ago, JG7_X-Man said:

 

...I agree, but only where they have been validated! Can't be making stuff up or going with "I think", or 'I feel" - we need hard facts backed by verifiable data. 

Enjoy your coffee, LOL.

 

Happy landings,

 

Talisman

[Diggun]

Memoirs are a secondary source at best. And pretty, err, divorced from reality at worst. E.g. Clostermann's 'The Big Show'. Very useful for a social historian, less so for a technical one.

[Talisman]

1 minute ago, [_FLAPS_]Diggun said:

Memoirs are a secondary source at best. And pretty, err, divorced from reality at worst. E.g. Clostermann's 'The Big Show'. Very useful for a social historian, less so for a technical one.

However, his credentials for giving us details on the Tempest V are impeccable.  He is not just any pilot.  The link below gives an idea of his credentials.  I would not expect this book to provide definitive details regarding Axis aircraft and would expect such details to be open to correction, but I would expect to be on very solid ground regarding details in this book regarding the Tempest V.  It is the Tempest V that the author is an expert and an authority on.

https://en.wikipedia.org/wiki/Roland_Beamont

 

Happy landings,

 

Talisman

[ICDP]

Don't make the mistake of going by thinks and feels and some vague assumption that 6-7 months later the Tempests were somehow 20mph faster.  You should always rely on first hand real test data, sowe can review it and present it to the devs.

Edited September 23, 2019 by ICDP

[Diggun]

That's fine, but he must have had an exceptional memory since that book was 1st published in 1994. And are we supposed to disregard the (multiply sourced) empirical data in favour of this 50 years after the fact memoir?

 

Beaumont DID definitely claim to have gone supersonic in a sabre. Which he didn't.

Edited September 23, 2019 by [_FLAPS_]Diggun

[ICDP]

5 minutes ago, [_FLAPS_]Diggun said:

That's fine, but he must have had an exceptional memory since that book was 1st published in 1994. And are we supposed to disregard the (multiply sourced) empirical data in favour of this 50 years after the fact memoir?

 

Exactly, pilot memoirs are good to read but they should never be used as a primary source of data on aircraft performance.  Was this 416 MPH number obtained on a cold day with a tail wind for example.  Should we use 416mph for the Tempest only and ignore the fact that the same conditions would also give a ~20mph boost to LW fighters.

Edited September 23, 2019 by ICDP

[sevenless]

1 hour ago, 56RAF_Talisman said:

Very informative read regarding the Tempest here: 
https://www.amazon.co.uk/Tempest-Over-Europe-Roland-Beaumont/dp/1853104523
 

 

Thanks. Looks like a good read. Order placed.

[JG7_X-Man]

My grandfather-in-law migrated to the US from Austria after WWII (...in which he fought in and was captured in the Battle of Rome/Ansio (...we (grandchildren) debate that topic every thanksgiving). Anyway, to this day be believes saw jetpacks in use - Yes actual jetpack!

Edited September 23, 2019 by JG7_X-Man

[Talon_]

Tempests were running +11lbs Sabre IIBs on 130 grade on the continent and going faster than the same boost on 150 grade Sabre IIAs in May 44.

 

The Sabre IIB is the accurate engine for Bodenplatte.

[CountZero]

109g14   570kmh autumn, 606kmh winter (+36kmh)
109 k4   607kmh autumn, 642kmh winter (+35kmh)
1.98k4   622kmh autumn, 659kmh winter (+37kmh)
190a8    581kmh autumn, 612kmh winter (+31kmh)
190D9    607kmh autumn, 616kmh winter (+9kmh)
P-47D    580kmh autumn, 599kmh winter (+19kmh)
Spit9m66 541kmh autumn, 568kmh winter (+27kmh)
La5FN    582kmh autumn, 613kmh winter (+31kmh)

 

so for Tempest then its not hard to belive it could do 416mph (669kmh) i winter if it did 394mph (634kmh) in spring, its +35kmh diff only, diff is simmilar to what airplanes in game get on SL when compared to autumn conditions and winter conditions. 

 

But as we are probably getting 9lbs only, speeds around 380mph are to be expected at best, +20mph on winter in best case scenarious

Edited September 23, 2019 by 77.CountZero

[Talisman]

30 minutes ago, ICDP said:

Don't make the mistake of going by thinks and feels and some vague assumption that 6-7 months later the Tempests were somehow 20mph faster.  You should always rely on first hand real test data, sowe can review it and present it to the devs.

Folks, what are you setting up here?  I have not mentioned 'thinks' and 'feels' but you have!  Further, you introduce the word 'mistake' in relation to the words I have not used. 

Nor have I said that I assume anything.  I have simply presented a body of work that can be taken on it's own merit by a man very qualified to produce that body of work.  I have put this information on the forum to inform and provide topic for discussion and I have made a suggestion regarding continuous improvement of engines and fuel, etc.  Please do not read into my posts things that I have not said and do not intend to say.

Objective criticism is fine, but leading the casual reader to perhaps believe that I have used words and made assumptions that I have not is rather impolite to say the least and leads me to question if your motives are friendly or not.

 

Happy landings,

 

Talisman

Edited September 23, 2019 by 56RAF_Talisman

[JG7_X-Man]

13 minutes ago, 56RAF_Talisman said:

...I have not mentioned 'thinks' and 'feels' but you have! 

 

I was referring to the excerpt from the book:

...In flight the tempest was exhilarating

He lost most after that, from that point on, this was a "My plane is better than your plane" argument.

 

 

Edited September 23, 2019 by JG7_X-Man

[Talisman]

3 minutes ago, JG7_X-Man said:

 

I was referring to the excerpt from the book:

...In flight the tempest was exhilarating

And you think that perhaps he is mistaken about that?

 

Happy landings,

 

Talisman

[HagarTheHorrible]

I suspect that if the Tempest seems to be included without all the possible bells and whistles it might be because it is strong enough to compete, without dominating, as is.  No one wants a "fun" flight sim if one side has an asset that, because of the possible vagaries of the game, rules the roost by too large a margin.  Lets just wait and see how it performs before we get all hot and bothered about figures.  If the Tempest underperforms compared to the competition, on release, then by all means crow for all you're worth.

[=RvE=Windmills]

24 minutes ago, HagarTheHorrible said:

No one wants a "fun" flight sim if one side has an asset that, because of the possible vagaries of the game, rules the roost by too large a margin.

 

That one is already ingame

[Talon_]

26 minutes ago, HagarTheHorrible said:

No one wants a "fun" flight sim if one side has an asset that, because of the possible vagaries of the game,

 

You mean the Me262?

[JG7_X-Man]

We only what aircraft based on data driven performance - and some opinion some 90 yr old going off memory.

 

I was as at the Air and Space museum in DC years ago talking to a pilot (owned a  F4U Corsair I believe), he was talking about how he found it hard to believe that a Spitfire I could out turn an me 109E because of the slats. It was pretty funny - he kept repeating "...but it had slats!" and "we still use that pioneering aeronautical engineering today!" Just saying - he is no aeronautical engineer so we we can't go by that.

 

 

Edited September 23, 2019 by JG7_X-Man

[RedKestrel]

11 minutes ago, =RvE=Windmills said:

 

That one is already ingame

 

9 minutes ago, Talon_ said:

 

You mean the Me262?

And the K4 1.98 ATA and the D9...

Let's be real, even if the Tempest releases with the lower boost settings/engine limits we're going to get the usual suspects demanding they be nerfed somehow after they get surprised when they bleed off all their speed from turning in a D9 or a 262 and get killed.
 

[ICDP]

1 hour ago, HagarTheHorrible said:

I suspect that if the Tempest seems to be included without all the possible bells and whistles it might be because it is strong enough to compete, without dominating, as is.  No one wants a "fun" flight sim if one side has an asset that, because of the possible vagaries of the game, rules the roost by too large a margin.  Lets just wait and see how it performs before we get all hot and bothered about figures.  If the Tempest underperforms compared to the competition, on release, then by all means crow for all you're worth.

 

I don't want balance, I want accuracy for all aircraft within a reasonable margin of error for a £50 flight simulation.  Is that too much to ask?

 

Joking aside I have always felt that pilot account should not be given any credibility over actual test results.  The RAE tests showed a Tempest + 9 lb hitting ~375mph at SL and the + 11 lb boost hitting ~395 mph.  With all due respect but for me they trump a pilots accounts every single time.  Flight tests are much more controlled and as a consequence the results are more accurate.

 

I don't doubt that during winter an + 11 lb boost Tempest would reach ~ 416 mph give the lower temperatures and lower air pressure.  The thing is even LW fighers obey the laws of thermodynamics and would be 15-20 mph faster in the same conditions.

Edited September 23, 2019 by ICDP

[CountZero]

1 minute ago, ICDP said:

 

I don't want balance, I want accuracy for all aircraft within a reasonable margin of error for a £50 flight simulation.  Is that too much to ask?

 

Joking aside I have always felt that pilot account should not be given any credibility over actual test results.  The RAE tests showed a Tempest + 9 lb hitting ~375mph at SL and the + 11 lb boost hitting ~395 mph.  With all due respect but for me they trump a pilots accounts every single time.  Flight tests are much more controlled and as a consequence the results are more accurate.

And tests data were not done in winter, but in more conditions we have on autumn maps in game. 

So when you see that radials in game get 12-20mph boost in SL speed on winter maps compared to autumn conditions, its not out of question that what pilot say in book is what happend, and 416mph is posible when test data shows ~395mph, in conditions similar to autum maps in game, but discusion is pointles as we aint geting 11lbs or 150octane.

[JtD]

You guys are mixing TAS (true air speed from test results) and IAS (indicated air speed from book). At speeds 360-400mph, the manual gives a 22mph correction. 416 would likely be even more, but still, 416-22 = 394. Perfectly plausible.

 

Edited September 23, 2019 by JtD

[CountZero]

Just now, JtD said:

You guys are mixing TAS (true air speed from test results) and IAS (indicated air speed from book). At speeds 360-400mph, the manual gives a 22mph correction. 416 would likely be even more, but still, 416-22 = 394. Perfectly plausible.

 

picture on first post shows 416mph IAS at sea level, so thats basicly same as TAS at that alt. And others pointing out at 395mph as max also talk about sea level TAS. Differance comes from weather conditions, as one talks about test in may 44 , while other about winter conditions.

Edited September 23, 2019 by 77.CountZero

[ICDP]

The test results I linked to on WWII Aircraft performance are corrected.

 

4. Results of tests.

 

4.1 General. The performance results have been corrected to standard ICAN atmospheric conditions and the level speeds to 95% of the take off weight i.e. 10,900 lb. In correcting the level speeds, the compressibility correction has been calculated by the methods given in the Addendum to Report No. A&AEE/Res/147. A strut correction to the IAS, based on ARC.6420 has also been applied.

2 minutes ago, 77.CountZero said:

picture on first post shows 416mph IAS at sea level, so thats basicly same as TAS at that alt. And others pointing out at 395mph as max also talk about sea level TAS. Differance comes from weather conditions, as one talks about test in may 44 , while other about winter conditions.

 

Yeah, as I posted above I believe the 416mph number is due to the colder winter weather.  Pretty much every aircraft in BoX gets a boost in colder weather so I suspect a Tempest would be the same.

[BubiHUN]

2 hours ago, Talon_ said:

Tempests were running +11lbs Sabre IIBs on 130 grade on the continent and going faster than the same boost on 150 grade Sabre IIAs in May 44.

 

The Sabre IIB is the accurate engine for Bodenplatte.

There was even far less numbers for that engine, and at the end of '45. 
 

[Talon_]

16 minutes ago, -[HRAF]BubiHUN said:

There was even far less numbers for that engine, and at the end of '45. 

 

By the end of 1945 the Sabre II was in service flying with the Bristol Centaurus engine, and the Sabre IIBs of 1944 had been upgraded in the Tempest V fleet to +13lbs with new props. In fact, Sabre IIAs were no longer manufactured after September 1944.

[mazex]

4 hours ago, 56RAF_Talisman said:

Also of interest, is the demonstrating of the Tempest V to VIP audiences, including visiting Russian generals on 30th August 1944.  Can any beta testers replicate this? 

Practical dive limit of 545 mph and fully manoeuvrable looks good too!
 

 

Hmm. Take off, climbing 45 degree turn to 1000 feet and then back over the field reaching 500 mph and a zoom to 8000 feet? That really feels like "a fond old memory" of the author? Would accept it if he was talking km/h.

 

I just barely managed to beat that in DCS with an F18 at full afterburner and no loadout. I reached 450 kts following those instructions ( = 517 mph). 

[ICDP]

37 minutes ago, mazex said:

 

Hmm. Take off, climbing 45 degree turn to 1000 feet and then back over the field reaching 500 mph and a zoom to 8000 feet? That really feels like "a fond old memory" of the author? Would accept it if he was talking km/h.

 

I just barely managed to beat that in DCS with an F18 at full afterburner and no loadout. I reached 450 kts following those instructions ( = 517 mph). 

 

See those two paragraphs of the book should be a raising questions to any rational person.  This is not disrespectful to the author but just simple rational thinking.  A realistic question to OP.  If you try that in the sim Tempest and inevitably fail, will you be on here claiming the Tempest is broken, or questioning if the author maybe exaggerated for dramatic effect?

 

Edited September 23, 2019 by ICDP

[JtD]

8 hours ago, 77.CountZero said:

picture on first post shows 416mph IAS at sea level, so thats basicly same as TAS at that alt.

 

No, it's not. Read up on IAS and the purpose of position error tables.

[CountZero]

Differnace in game in top speed on deck is exactly as expected around 30kmh, 623kmh (387mph) on autumn map at 50m, and 653kmh (407mph) on winter map at 50m when using +11lbs.

So all looks ok, when comparing performanc chart 375mph and pilot report 416mph, differance is same around 20mph in game and reports in this topic, so that 416mph from book is do winter conditions.

Edited September 30, 2019 by 77.CountZero