Bf-109K

[Nikademus]

Yes, the poster is also listing what appears to be TAS at higher altitude.

This tells us absolutely nothing about the relative velocity. To do that we must convert to EAS.

The effect of altitude is to increase velocity by the SMOE. An aircraft traveling a velocity of 200KEAS at sea level is traveling 200KTAS.

An aircraft traveling 200KEAS at 35,000 ft is traveling 326KTAS.

Both aircraft however are traveling at exactly the same velocity of 200KEAS and neither aircraft has any speed advantage. One just benefits from the effects of altitude.

A quick SWAG of altitude effects using the data provided in this thread shows the Bf-109K4 to be traveling at an equivalent airspeed of 299mph while the P-47N is traveling at 272mph.

440mph / 1.4678<SMOE FL24> = 299 mph EAS
467mph / 1.71295<SMOE FL325 = 272mph EAS

The Bf-109K4 is the faster of the two aircraft according to this data.

yikes. LoL. After reading posts like this along with others, it didn't suprise me that gentlemen like the one who authored the post i was using as an example chooses to hang out on a gaming website vs. a dedicated aviation forum on which to "educate" us with the facts

Unfortunately, I must include myself in the "aviation for dummies" catagory at least when it comes to breaking down the science of flight itself. Can you walk me through the above a little more in terms of definition of terms/abreviations and how the formulas are used?

All aircraft traveling at the same angle of bank and velocity will make exactly the same turn. There is no difference in maneuverability between a P-47 traveling at 200mph KEAS and a Bf-109K4 at 200mph KEAS. At a 60 degree bank both aircraft will exactly the same turn.

Sustained maneuvering envelope will be determined by the excess power characteristics and the shape of polars.

How would you factor in roll rate at x altitude and y speed and rate of turn?

The P47N generates a considerable amount of power at FL325. It also requires a considerable amount of power at FL325. A very quick SWAG of the Nzmax sustainable shows that at combat weight, the P47N is very close to the Bf-109K4 at 1.8ata at Take Off weight. The Bf-109K4 at 1.98ata has a substantial advantage.

In my SWAG I do convert using standard formulation from listed IAS with the types PEC.

SWAG?

 

[Crumpp]

How would you factor in roll rate at x altitude and y speed and rate of turn?

What is the importance of roll rate or how do I calculate it?

Calculating it is far beyond the scope of this thread. I can give you some very rough ballpark techniques is all.

t factor, p, and several other characteristics are generally derived from test data.

Lateral dynamics are extremely complicated.

Roll rate represents a designs agility or ability to change the orientation of the vector of lift.

SWAG - Scientific Wild Azz Guess

All the best,

Crumpp

 

[Crumpp]

Can you walk me through the above a little more in terms of definition of terms/abreviations and how the formulas are used?

SMOE - Standard means of evaluation - Term used to descibe 1/SQRT sigma. Sigma is the density ratio which equals pressure/pressure at sea level on a standard day. Pressure units are in slugs/ft^3

To convert velocity in EAS to TAS we have to account for density effects of the atmosphere.

Here is a primer on airspeed:

Airspeed - Wikipedia, the free encyclopedia

All the best,

Crumpp

 

[marshall]

A quick SWAG of altitude effects using the data provided in this thread shows the Bf-109K4 to be traveling at an equivalent airspeed of 299mph while the P-47N is traveling at 272mph.

440mph / 1.4678<SMOE FL24> = 299 mph EAS
467mph / 1.71295<SMOE FL325 = 272mph EAS

The Bf-109K4 is the faster of the two aircraft according to this data.

I'm not sure that this is fair to say with that info that 109 is faster, because in the above calculations P-47 is 6500ft (2km) higher, so when it would be lower on the same alt as 109 it of course would have smaller max TAS but that still could be more than 440mph for example 441mph. I'm not saying that P-47 is faster, I just think it's not enough info to say that 109 is faster.

 

[Crumpp]

Marshall,

Equivilent Airspeed removes the effects of altitude you understand that right? That is why engineer's use EAS to compare performance and not TAS.

so when it would be lower on the same alt as 109

Altitude effects are removed so the aircraft ARE essentially at the same altitude or at least in a comparible condition of flight.

Understand?

All the best,

Crumpp

 

[Crumpp]

Range at most economical cruise. Not a good idea in a airspace dominated by the USAAF if one wants to live to old age.

P-47D-25-RE: range ~1500 miles. Range with maximum external fuel was 1800 miles

I am confused as to the point you where trying to make. Is Kurfurst somehow being deceitful for listing the range of the aircraft or are you simply pointing out that the range occurred at L/Dmax like every other airplane?

Was the P47 somehow more advantaged when flying at Best Range cruise velocity?

All the best,

Crumpp

 

[marshall]

Marshall,

Equivilent Airspeed removes the effects of altitude you understand that right? That is why engineer's use EAS to compare performance and not TAS.



Altitude effects are removed so the aircraft ARE essentially at the same altitude or at least in a comparible condition of flight.

Understand?

All the best,

Crumpp

Yes now I understand, my bad but from where do you take the numbers that you divied TAS with them?

 

[Crumpp]

ME109 K -- Max airspeed: 440 mph at 7500m (about 24,000 feet).
ME109H -- Max airspeed 452 mph at 19,685 feet.
ME109G8++ -- Max airspeed 426 mph at 24,280 feet
ME109G1-G6 -- Max airspeed 386 mph at 22,640 feet

P-47N -- Max airspeed 467 mph at 32,500 feet.
P-47C -- Max airspeed 433 mph at 30,000 feet.

What part of these stats do you not comprehend? As high-altitude fighter go, the P-47, even the P-47C, could beat the stuffing out of ANY variant of the ME-109 at altitudes above about 28,000 feet.

No claims are made as to the validity of the data. I was just pointing out that unless you know what your doing, these comparison threads are really silly.

When you do know what you're doing, they become even sillier. All aircraft performance is a percentage range over a mean average. The performance any aircraft exhibits as "normal" can have a very wide swath.

IMHO, the middle of the envelope is the most interesting. The Prmin point, L/Dmax, and Cl^3/2/Cd are where we really find some unique differences in some of our WWII designs. That and the stability and control issues as it was a very new science at the time.

All the best,

Crumpp

 

[AL Schlageter]

I am confused as to the point you where trying to make. Is Kurfurst somehow being deceitful for listing the range of the aircraft or are you simply pointing out that the range occurred at L/Dmax like every other airplane?

I don't think it is that hard to understand what was said.

A 1000 miles might be good for a delivery flight to the EF where there was no chance of being bounced but once there the typical combat radius was ~140 miles.

I wouldn't say he was being deceitful but more like being dishonest as he failed to say if the range was clean, with drop tank, or with drop tanks.

 

[Kurfürst]

You are just flamebaiting by posting false data in one of your many handles after the others have been banned, that much is clear.

 

[Crumpp]

A 1000 miles might be good for a delivery flight to the EF where there was no chance of being bounced

You understand that the same goes for the P47 or any other aircraft right?

The difference between Min Specific fuel consumption and Take Off power being 60 gallons per hour and 275 gallons per hour respectively for the P47.

All aircraft had to watch their fuel. The USAAF more so than the Luftwaffe when over Germany.

So these cruising Bf-109's are going be bounced by cruising P47's.

All the best,

Crumpp

 

[Juha]

IMHO P-47 versions that were used same time in Europe than 109K were late Ds and Ms. The latter was used by the last remaining 8th AF P-47 group, 56FG in 1945.
Performance of the P-47M-1-RE included a maximum speed of 400 mph at 10,000 feet, 453 mph at at 25,000 feet, and 470 mph at 30,000 feet. Initial climb rate was 3500 feet per minute at 5000 feet and 2650 feet per minute at 20,000 feet.
In fact it seems that actual test gave the rate of climb for P-47M as at S/L 3960 ft/min, 3740 ft/min at 10000ft and 3300 ft/min at 20000ft.

Juha

 

[Crumpp]

Performance of the P-47M-1-RE included

AFAIK the first P-47M's arrived in Europe on 04 Mar 1945 but were grounded due to engine difficulties digesting their special fuel until April 1945, just days before the war ended.

You could say the P-47M is a contemprary of the Ta-152H series and FW-190D13 series more so than the Bf-109K series. IIRC, the Bf-109K4 was operational much earlier in the war than the P47M.

All the best,

Crumpp

 

[AL Schlageter]

Where did you get that mis information?

The first P-47M was delivered from the factory in December 1944 with the 56FG getting their first on Jan 3 1945.. On Jan 14 1945 Paul Gonger made a claim of a 109.

There was problems with the high tension leads cracking (P-47Cs had a similar problem). There was some other problems like defective carb diaphrams, cylinder corrosion and over cooling but fuel was certainly not one of the problems.

On Feb 3 1945 a mission was flown to Berlin.

Yes they were grounded but all the FSs of the 56FG were flying P-47Ms by mid March 1945.

 

[Crumpp]

Where did you get that mis information?

No misinformation is posted. As I understand the documentation, they arrived at the group for operational testing then but were not posted to operational status until 04 Mar 45. Only half the squadron aborted with mechanical difficulties on their first mission in January. The other half flew the mission for the operational trials. Assesments were still needed of types usefulness in combat.

If you want to say that the type was operational from Jan 45 you are free to do so. IMHO, it would be like claiming the FW-190D9 was operational in October 1944. That would not be true however as the type was undergoing operational trials, the last phase of the testing regime to asses its worth as a combat aircraft before acceptance by the gaining service.

The type maintained this dismal relability rate throughout the trials until Pratt and Whitney got involved. Unfortunately Pratt and Whitney's solution turn out not to be the answer and it appears the type was prematurely posted to operational status.

The 50% abort rate the operational trials averaged was never fixed so that when on the very first mission in operational status, it led to the type being grounded until April 1945 so that relability could be increased to an acceptable level for a USAAF Operational Squadron.

Once again, the P47M was not a contemporary of the Bf-109K but belongs alongside the Ta-152H series, FW-190D13 series, and other late war aircraft that were not developed designs by wars end.

That is my opinion. You are entitled to paint the aircraft as fully developed and a viable operational aircraft if you like.

All the best,

Crumpp

 

[Juha]

Hello Crumpp
based on secondary sources only I tended to side Al here. It seems that 47M was grounded twice, a couple days in late Feb and from 16th to 24th March 45. Time to 31th March was troublesome but by leafing through McLaren's Beware the Thunderbolt! abort rate wasn't anywhere near 50% during first half of March. And 56th flew ops almost daily. Usually understreght, maybe 50% included also those not even booked for mission?

Juha

 

[davparlr]

The 109K wasn`t a 'stripped down, point defense' version. It was, basically, a normal fighter like the 109G with an aerodynamically refined airframe and a later, improved high altitude engine. Actually it`s the heaviest version, but the difference is not particularly great compared to other 109G models. Like all 109s, it`s benefitted from the base concept of combining a small, light airframe with a powerful engine.

Bf-109G-6 empty weight – approx 6000 lbs (multiple sources)
Bf-109K-6 empty weight – 5161 lbs (similar to the G-10)

Somewhere between the G-6 and K, 800 lbs was lost.

Range of the Bf 109F/G/K was 1000 miles, not 350.

Wikipedia states that the Bf 109G-6 has a range, with drop tank, of 1000 km (621 miles), 528 mile without. My other sources do not support your statement either, for the F (440 miles) or G (450 miles).

It had three guns, one 30mm MK 108 and two 13mm MG 131s (the G-10/U4, G-14/U4, G-6/U4 carried the same), whereas the basic G-6, G-14, G-10 and their AS models carried the 20mm MG 151/20 cannon instead of the 30mm.

I was wrong assuming that the K had the same armament as the G-10.

I fail to see any climb advantage for the P-47N. The figures show only up to 28k feet, or 8500 meter, where it does, and 14 000 lbs weight, something like 2200 fpm, or about 11.2 m/sec. Corresponding figure for the 109K is 11.4m/sec, the same for all practical purposes. Below that altitude the climb advantage of the 109K is pronounced. OTOH, the P-47N has speed advantage in the extreme altitude regions thanks to it`s sizeable turbocharger. Up to the most common altitudes however, the 109K holds some slight speed advantage, and considerable climb rate advantage.

Actually, I got the wrong P-47 for Europe. The M was the one that the Bf 109K could have met. And while the Bf-109K would have been superior below 25k ft, the advantage would have shifted at 25k and above. For example, at 25k ft, the Bf 109K max airspeed is 444 mph, climb rate 2700 ft/min, the M's is 453 mph and 2700-3000 ft/min, at 28k ft, the K can do 441 mph and climb at 2220 ft/min, the M can co 463 mph and climb at 2700 ft/min. It gets worse at 30k ft. where the K does 438 mph and climbs at 1900 ft/min, while the M can make over 460 mph and climb at 2200 ft/min.

Basically, the two aircraft display typical qualities of a lightweight, high powered interceptor and a heavier, long range fighter with high fuel capacity. The former sports high performance and agility, high caliber weapons, the latter`s greatest virtue is it`s operational radius.

I am not an armament guy but I suspect there are those that would argue that two 50 cals and a 30 mm does not exhibit better firepower than eight 50 cals. Especially for a fighter.

AFAIK the first P-47M's arrived in Europe on 04 Mar 1945 but were grounded due to engine difficulties digesting their special fuel until April 1945, just days before the war ended.

You could say the P-47M is a contemprary of the Ta-152H series and FW-190D13 series more so than the Bf-109K series. IIRC, the Bf-109K4 was operational much earlier in the war than the P47M.

No misinformation is posted. As I understand the documentation, they arrived at the group for operational testing then but were not posted to operational status until 04 Mar 45. Only half the squadron aborted with mechanical difficulties on their first mission in January. The other half flew the mission for the operational trials. Assesments were still needed of types usefulness in combat.

If you want to say that the type was operational from Jan 45 you are free to do so. IMHO, it would be like claiming the FW-190D9 was operational in October 1944. That would not be true however as the type was undergoing operational trials, the last phase of the testing regime to asses its worth as a combat aircraft before acceptance by the gaining service.

The type maintained this dismal relability rate throughout the trials until Pratt and Whitney got involved. Unfortunately Pratt and Whitney's solution turn out not to be the answer and it appears the type was prematurely posted to operational status.

The 50% abort rate the operational trials averaged was never fixed so that when on the very first mission in operational status, it led to the type being grounded until April 1945 so that relability could be increased to an acceptable level for a USAAF Operational Squadron.

Once again, the P47M was not a contemporary of the Bf-109K but belongs alongside the Ta-152H series, FW-190D13 series, and other late war aircraft that were not developed designs by wars end.

That is my opinion. You are entitled to paint the aircraft as fully developed and a viable operational aircraft if you like.

I disagree with these comments. The first delivery of the Bf 109k was in October, 1944. The first delivery of the P-47N was September, 1944, one month earlier. I could not get a delivery start date for the P-47, but considering that in December, 1944, 130 P-47M were delivered and only 24 "N"s, it is reasonable to assume that delivery of the first P-47Ms was in the September, or before, time frame. This does not justify the statement that the P-47M or N was not a contemporary of the Bf-109K. Maintenance problems appear to be minor from a mechanical standpoints (there were some deaths) since the initial problems occurred in March and the P-47Ms were operational in April. I am sure that the reason that the P-47M was not introduce until early '45, was because the Allies were not as hard pressed to introduce new technology as were the Germans. I am sure that the Bf 109K did not go through as rigorous testing as Allied aircraft nor did the pilots go through as intensive checkout as the Allied pilots. It probably took the US four to six months to get a new aircraft, once delivered into the fighting squadron, how long do you think it took the Germans to fly the first operational mission after the Bf 109K was delivered? Probably days. I am also sure that had the Allies been threatened in early to mid '44 by the Luftwaffe retaking control of the skies over Germany, you would have seen the P-47M and N, and probably P-51H fully operational in the fall of '44. As it were, they had the highly capable P-51B/Ds and P-47D-25s that, in the quantities available, easily handled the Luftwaffe and any of the advance aircraft, including jets, they could throw up. There was just not a lot of pressure on the Allies to field advanced technology aircraft, except in Pacific, where Kamikazes were a real threat to the fleet.

 

[Nikademus]

I disagree with these comments. The first delivery of the Bf 109k was in October, 1944. The first delivery of the P-47N was September, 1944, one month earlier. I could not get a delivery start date for the P-47, but considering that in December, 1944, 130 P-47M were delivered and only 24 "N"s, it is reasonable to assume that delivery of the first P-47Ms was in the September, or before, time frame. This does not justify the statement that the P-47M or N was not a contemporary of the Bf-109K.

Well, for what it's worth, this website author would appear to agree with Crump's assertation regarding the hotrod versions of the P-47

The performance of the YP-47M was excellent, with a top speed of 761 KPH (473 MPH), and the variant was rushed into production to counter the threat of the new German V-1 cruise missiles and German jet fighters. 130 P-47Ms were built, with the first arriving in Europe in early 1945. However, the type suffered persistent teething problems in the field and did not see much action until the war was all but over.

The Republic P-47 Thunderbolt

If the above has a fair degree of accuracy, I'd say it's probably more fair to rate the worked up P-47M/N series against the TA-152H which was Germany's next generation answer to the high alt fighter. The 109K varient I still consider somewhat of an interim fix using an aging airframe passing into obsolecense. They did a decent job considering but ultimately it was falling behind the curve of the newer airframes like the 47.

 

[Nikademus]

What is the importance of roll rate or how do I calculate it?

Actually I was referring to the straight up comparisons that usually occur in these "comparison type" threads. In this case (P-47 vs Me-109) at high altitude it was asserted that the Thunderbolt could "outroll" and "out-turn" the Me-109.

As mentioned, I've read that the Thunderbolt was suprisingly agile and nimble for such a huge fighter in the thin air @ 30+K. But i'm wonder how much more agile it really is. I understand you to say that two planes turning in the same way are identical. The assertation is that one plane can turn/roll more sharply than the other at x speed.

SWAG - Scientific Wild Azz Guess

All the best,

Crumpp

LoL. Thought that was what you meant.

 

[Nikademus]

The effect of altitude is to increase velocity by the SMOE. An aircraft traveling a velocity of 200KEAS at sea level is traveling 200KTAS.

An aircraft traveling 200KEAS at 35,000 ft is traveling 326KTAS.

Both aircraft however are traveling at exactly the same velocity of 200KEAS and neither aircraft has any speed advantage. One just benefits from the effects of altitude.

A quick SWAG of altitude effects using the data provided in this thread shows the Bf-109K4 to be traveling at an equivalent airspeed of 299mph while the P-47N is traveling at 272mph.

440mph / 1.4678<SMOE FL24> = 299 mph EAS
467mph / 1.71295<SMOE FL325 = 272mph EAS

The Bf-109K4 is the faster of the two aircraft according to this data.

Wow....my head is spinning. How did you get the numbers?

SMOE - Standard means of evaluation - Term used to descibe 1/SQRT sigma. Sigma is the density ratio which equals pressure/pressure at sea level on a standard day. Pressure units are in slugs/ft^3

To convert velocity in EAS to TAS we have to account for density effects of the atmosphere.

Here is a primer on airspeed:

Airspeed - Wikipedia, the free encyclopedia

All the best,

Crumpp

Thx for the link. Started looking at it, but admitedly all the math is confusing the hell out of me. I'm still not sure I understand why EAS is more accurate than TAS unless its because the TAS indicator is misleading the pilot because thats what his instrument states but his actual airspeed is calculated via the EAS formula.......

Almost makes me long for the days of Zero vs Wildcat. aieee.