Bf-109K

[Crumpp]

The first delivery of the P-47N was September, 1944

My comments are about the P47M.

It seems that 47M was grounded twice, a couple days in late Feb and from 16th to 24th March 45.

During the operational trials in Feb it was grounded, yes.

Don't confuse operational trials with operational service, however.

In operational service it was again grounded in March. The mission was flown on 04 March 45 as I understand it. The CO of the 56th FS grounded the type and reverted back to their D models which were still on the flight line.

AFAIK, It was grounded because the aircraft was unreliable and was maintaining an average of a 50% abort rate in the squadron.

This would have generated paperwork officially grounding the type and requesting the technical resources to address the problem and get the type ungrounded. I have no doubts those dates originate from such paperwork.

You are free to have your own opinion on this too.

As a pilot, IMHO, this is a really silly argument. The aircraft was not ready for service and had some serious difficulties due to its fuel. While it might seem really peachy to have such an aircraft when you just hit the reset button, a real pilot is risking death a large percentage of the time. He is gambling that he can make it safely to the ground in a machine that has a very good chance of not working properly. There was good reason to ground it and the operational trials were due to end in March. AFAIK, they did end in March after the grounding in February and Pratt and Whitney's assurances the type would be reliable.

It did not work out that way and the type was again grounded in March.

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

Several designs experienced this over their lifecycle. Look at the La series in service with the VVS. It does not mean they are "stripped down". Many times just changing a designs dimpling can have a large benefit in weight savings.

Be careful when reading specific engine charts if you do not understand what you are doing. Just warming up, the R-2800 requires 45 gallons of fuel and the P47 has 33 gallons of unusable fuel on board. Some range estimates do not include a reserve while others list a radius.

Make sure too that the engine is capable of operating at its maximum range settings at the altitude under discussion.

Range data is also listed for a specific altitude in many cases. The range will change based on altitude!

I don't care to argue with game sim fans about when or where their favorite aircraft came into service or how much better it was than all the other game shapes. It's not my cup of tea.


All the best,

Crumpp

 

[Crumpp]

How did you get the numbers?

Using standard airspeed formulation and converting the numbers from True airspeed back to Equivalent airspeed.

Equivalent airspeed is what is used to compare aircraft performance from one type to another. True Airspeed is not used for comparison purposes.

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.

Yes agility is very important. The differences in any aircraft sustained turning envelope is a very tiny percentage of the total maneuvering envelope.

An aircraft like the P47 which did have a good roll rate AFAIK, would be a formidable opponent. He can establish a turn faster than a less agile opponent and can use that agility to change the orientation of his vector of lift.

What does that mean? Well any time the vector of lift is pointed below the horizon, a component of weight adds directly to thrust.

AT a combat weight of 12,257lbs a P47D-22 adds 2128lbs of thrust if it drops the vector of lift just 10 degrees below the horizon. In power producers, the faster we go, the less thrust our aircraft produces.

So at 145KEAS our P47D-22 produces 4953lbs of thrust. If we roll our vector 10 degrees below the horizon, we now add 2128/4953 x 100 = 42.9% increase in our Thrust available. This directly translates to Nzmax sustainable and our aircraft can now turn much better. It is a shallow diving turn but our pilot can still pull lead and use the agility of the aircraft to roll the wings level and zoom to gun solution. In ACM, this is called a Yo-Yo.

At 280KEAS our P47 produces 2565lbs of thrust and we can increase our thrust by 2128/2565 x 100 = 82.9% with the same roll.

All the best,

Crumpp

 

[Nikademus]

Using standard airspeed formulation and converting the numbers from True airspeed back to Equivalent airspeed.

ok. In this case:
440mph / 1.4678<SMOE FL24> = 299 mph EAS
467mph / 1.71295<SMOE FL325 = 272mph EAS

How did you calculate the 1.4678 and 1.71295. Thats where i was going "huh?"

Equivalent airspeed is what is used to compare aircraft performance from one type to another. True Airspeed is not used for comparison purposes.

k. Dumb question. Why do we always see TAS listed for max speed on most sources? Are you saying it has no relevence what-so-ever?

Yes agility is very important. The differences in any aircraft sustained turning envelope is a very tiny percentage of the total maneuvering envelope.

Agreed. I noticed that in reading numerous accounts. Even in the case of the Zero at times. That and the influence of other outside variables.

An aircraft like the P47 which did have a good roll rate AFAIK, would be a formidable opponent. He can establish a turn faster than a less agile opponent and can use that agility to change the orientation of his vector of lift.

Agreed. I read a similar attribute to the P-40. Unless at very high speeds it couldn't turn with say, an A6M or Ki-43, but it's very good roll rate might give it a window of opportunity during the initial manuever. The trick was knowing when that window expired leaving the P40 driver in a losing turning battle with a dangerous drop in speed/energy.

All that you wrote not withstanding, I'm still finding myself looking for a more definitive answer. (apologies) Was the P-47 more manueverable at high alt than the 109 in terms of roll/turning rate? equal? inferior? Thats the question i keep asking and that the texts....online and book source don't clearly answer. They say it was "formidable", "agile", "nimble" but its hard to put it into context in the face of simplistic comparisons like the one i posted.

Sorry for being a math challenged pain the arse.

 

[marshall]

ok. In this case:
440mph / 1.4678<SMOE FL24> = 299 mph EAS
467mph / 1.71295<SMOE FL325 = 272mph EAS

How did you calculate the 1.4678 and 1.71295. Thats where i was going "huh?"

I also would like to know that.

 

[Crumpp]

Nikademus,

I don't know that I am up to teaching an aerodynamics course in this thread.
My suggestion is that you all attend a college class at your local community college. You will certainly enjoy it and learn quite a bit.

We use equivalent airspeed to compare performance because the forces of flight are equal at the same EAS. Dynamic pressure is constant at the same EAS.

True airspeed is very useful for flight planning purposes. A variety of information can be derived from it such as our ground speed. It is of little value if your goal is to compare one aircraft with another though, especially using data taken from differing altitudes.

Remember too that there was no standard atmosphere in WWII. The groundwork had been laid but nothing that bound any firm or country to a standard. There were atmospheric variations which can make a difference.

Here is the methodology I used to convert the listed airspeed. The atmospheric model I used was the NACA 1922 atmosphere which was a commonly used one in the US.

All the best,

Crumpp

 

[Crumpp]

How did you calculate the 1.4678 and 1.71295. Thats where i was going "huh?"

That comes off a standard atmospheric table.

 

[Crumpp]

All that you wrote not withstanding, I'm still finding myself looking for a more definitive answer. (apologies) Was the P-47 more manueverable at high alt than the 109 in terms of roll/turning rate? equal? inferior? Thats the question i keep asking and that the texts....online and book source don't clearly answer. They say it was "formidable", "agile", "nimble" but its hard to put it into context in the face of simplistic comparisons like the one i posted.

Good luck in your quest. My answer would be "It depends." The largest influence on performance being the man at the controls.

All the best,

Crumpp

 

[davparlr]

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 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.

I disagree. The N, and most likely the M, certainly was produced before the Bf-109k and was no more complex than the mod of the Bf-109k only the k had a more mature engine design. Of course we don't know if the k had any engine problems. Again, had the need existed, both aircraft could have met the k within a month or two in spite of some engine corrections.

 

[Crumpp]

Republic rushed vice-president Hart Miller to England to aid in the problem-solving but this soon grew to nightmare proportions when it became obvious that every P-47M operated by the 56th was stricken with some form of problem. Since this was a major problem, the USAAF and P&W assigned their best maintenance crews. Ignition leads were suspect and they were replaced with a different type but the problem would not go away and it seemed that the -57 powerplant was an engine fated not to run.

Using the WEP setting meant that P-47M pilots would be able to pass the fastest Mustangs at altitude but it would be at a distinct price since the engine at that setting would be consuming an astonishing 330 gallons per hour! The late D Model Thunderbolts could carry 370 gallons of fuel internally so it did not take a genius to figure out the range.

Airflow to the cylinders was modified so that the heads could heat to the most efficient temperatures. It was discovered that the sensitive engine/turbosuper-- charger controls were not being correctly operated, so additional training for pilots was required along with some modifications. Considerable minor modifications and fine-tuning meant that the engine gradually gained a degree of reliability but, eventually plagued by just too many problems, the engines of every operational M were changed in an attempt to gain combat readiness.

As the war in Europe fought to a close, the P-47M was finally operationally deployed during April 1945

High altitude thunderbolt Air Classics - Find Articles

All the Best,

Crumpp

 

[AL Schlageter]

AFAIK the first P-47M's arrived in Europe on 04 Mar 1945

Nice of you to ignore the fact the P-47Ms arrived in GB in early Jan 1945.

You have yet to post any info on this supposed fuel problem. 44-1 fuel passed testing in July 1944.

That is one heck of an operational trial flying a 5.5hr mission deep into enemy territory (Berlin) on Feb 3 1945.

Don't confuse operational trials with operational service, however.

So you would say the Me262 did not have operational status with Erprobungskommando 262 and Kdo Nowotny. That would make the Gloster Meteor the first operational jet powered plane.

Same could be said for some of the Me109s like the 1.98ata one.

 

[Nikademus]

Good luck in your quest. My answer would be "It depends." The largest influence on performance being the man at the controls.

All the best,

Crumpp

I didn't realize it was the holy grail. Perhaps if i bring onto thee....a Shrubbery.


Kidding aside, yes, i realize that the man at the controls as well as other outside variables ultimately impact the combat which is what makes stat-tic comparisons all the more meaningless when the testosterone starts to fly. At times though, some people manage to come up with figures like in the attached pic. I was wondering if similar information existed for the 109 and P-47.

 

[Nikademus]

I disagree. The N, and most likely the M, certainly was produced before the Bf-109k and was no more complex than the mod of the Bf-109k only the k had a more mature engine design. Of course we don't know if the k had any engine problems. Again, had the need existed, both aircraft could have met the k within a month or two in spite of some engine corrections.

I'm not too big into the "had the need existed, it would have been done" line of reasoning. I've heard the same thing used in regards to Me-262 discussions. (i.e. the P-80 would have been deployed much sooner had the need existed) Yet in recent 8th AF literature, such a postulation is not put forward.

 

[Nikademus]

That comes off a standard atmospheric table.

Can one find a table on the Internet?

 

[Nikademus]

Nikademus,

I don't know that I am up to teaching an aerodynamics course in this thread.
My suggestion is that you all attend a college class at your local community college. You will certainly enjoy it and learn quite a bit.
Crumpp

Ok. Thx for the info and the chart. It'll give me something to fiddle with between Quarters. 8)

 

[davparlr]

Several designs experienced this over their lifecycle. Look at the La series in service with the VVS. It does not mean they are "stripped down". Many times just changing a designs dimpling can have a large benefit in weight savings.

Be careful when reading specific engine charts if you do not understand what you are doing. Just warming up, the R-2800 requires 45 gallons of fuel and the P47 has 33 gallons of unusable fuel on board. Some range estimates do not include a reserve while others list a radius.

Make sure too that the engine is capable of operating at its maximum range settings at the altitude under discussion.

Range data is also listed for a specific altitude in many cases. The range will change based on altitude!

Of course. All these data points have many variables that we cannot control. We only have the data available to asertain aircraft performance. We typically try to find the most reliable available but it is often difficult to find if it exist. That doesn't stop us from debating and learning.

I don't care to argue with game sim fans about when or where their favorite aircraft came into service or how much better it was than all the other game shapes. It's not my cup of tea.


All the best,

Crumpp

I beg your pardon! There are many people on this site that are extremely knowledgable about various subjects and, while I might disagree with them, I admire them highly and respect their opinion and most of the young gamers tend to have interesting questions and make reasonable comments (or they don't stay here long). As for me, I have a bachelor in Math, a master in Aeronautical Systems, and have worked for over 30 years in the aerospace industry including time as a military pilot and a design engineer and manager for advanced military fighter and bomber aircraft. I am sorry that discussing war planes with us is not your cup of tea.

 

[davparlr]

Equivalent airspeed is what is used to compare aircraft performance from one type to another. True Airspeed is not used for comparison purposes.

Crumpp

I don't understand this comment. Almost all the data I have seen on aircraft is in TAS including record setting activity. In reality, at a given altitude, TAS is an accurate reflection of aircraft performance for comparison. Since combat is usually at roughly the same altitude, TAS performance between two aircaft is a accurate comparison. For example, if aircaft A can fly at 400 mph TAS at 20,000 ft and aircraft B can only fly 350 mph TAS at 20,000 ft, then if they are in combat at 20,000 ft, aircaft A has a clear airspeed advantage. And I am not sure I understand the value of the point you were trying to make on comparing the equivalent airspeeds at different altitudes-

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

Obviously, a plane going 467 mph may be slower than the other plane at the lower altitude and just maybe the one going 440 mph may go faster than the other plane at higher altitude, however, this does not necessarily reflect impact of EAS so much as it reflects the optimization of the superchargers. Could you explain the importance of EAS to aircraft performance comparison in more detail?

Also, just because the aircraft that is going at 299 mph EAS, it does not mean that it is going faster than the aircraft going 272mph EAS. If the plane going 467 mph TAS (272 mph EAS) leaves New York along with the plane going 440 mph TAS (299 mph EAS), and there is no wind factor between the various altitudes, the first plane (with the lower EAS) will arrive in Washington ahead of the other (with the higher EAS).

 

[Crumpp]

I beg your pardon!

If the shoe fits then wear it. If it does not, then it probably does not apply to you!

I certainly enjoy these aircraft. That is why I fly and work so hard at restoring these aircraft to flight.

I am all for discussing aircraft, their history, and learning something or passing some knowledge on.

I also not into your attitude towards me either. If you were more secure in your position, I don't think I would be explaining my comment to you. It would be self evident. If you have worked so hard in the industry, WHY AM I EXPLAINING EAS TO YOU???? I have never had to explain that to someone who is versed in aeronautical science, it is a given and industry standard.

For that matter why did I have to explain the basis for TBO determination in the other thread?

I don't understand this comment.

Could you explain the importance of EAS to aircraft performance comparison in more detail?

The dynamic pressure remains constant over EAS. Dynamic pressure changes over TAS.

Co-efficient of lift and drag are nothing more than the ratio of dynamic pressure to lift or drag pressures.

Holding our dynamic pressure steady gives a basis to compare aircraft performance. This is why engineers use EAS for performance comparison purposes.

When we convert from EAS to TAS, the aircraft has nothing to do with it. The conversion is based on the physical properties of the atmosphere.

EAS just eliminates the density differences in the atmosphere as a factor.

Since our original poster placed data from different altitudes, I simply eliminated the altitude as a factor for comparison.

Can one find a table on the Internet?

You should be able to find STD ATM charts on the internet. Most of them are the 1976 standard.

I have done an analysis of the Bf-109 series, Spitfire series, P 51 series as well as the P-47D-22, Nzmax sustained for one of the other members of this forum. That thread is in this forum. In fact I am supposed to do an analysis of the Me-262 for him too. Unfortunately, it just takes time and this a really busy part of the year. Just have not had the chance to work on it.

I would be happy to give it my best shot in teaching you some techniques for determining aircraft performance. PM me so we do not clutter up this thread.

All the best,

Crumpp

 

[Crumpp]

Nice of you to ignore the fact the P-47Ms arrived in GB in early Jan 1945.

Yes I it would have been more accurate to say they arrived in Jan 44 but were unable to pass operational trials until April 45.

It is not more accurate to characterize the aircraft as being on normal operational status from the date of their arrival on. That is just a misrepresentation IMHO.

Again, that is my opinion and you are free to form your own.

Once again this is a very silly discussion IMHO. I don't think any pilot would be thrilled to have to fly an aircraft with such a high failure rate. They certainly would not have classified it as a viable operational type.

That is one heck of an operational trial flying a 5.5hr mission deep into enemy territory (Berlin) on Feb 3 1945.

Well when that is the kind of operations your Air Force is doing, it only makes sense right?

All operational trials are conducted under actual operational conditions. That is why they are termed "Operational Trials".

Erprobungskommando 262

I don't think you have much knowledge of the language at all because your question is nonsensical.

Test Command 262......

Yes, the 262 was under operational testing status in Erprobungskommando 262.

Now the Luftwaffe did some unusual things. They formed test commands for specific types and on occasion these commands continued on with other aspects of testing while previous results entered operations.

The Luftwaffe formed these test units for specific test regiments. You would have to look to Erprobungskommando 262's specific mission for details on the scope of their responsibility.

Erprobungskommando 190 for example was jointly manned by Focke Wulf factory pilots and Rechlin pilots. Its final mission was to convert II/JG26 to type and then it was disbanded. II/JG26 conducted the operational trials of the FW190A.

All the best,

Crumpp

 

[Kurfürst]

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.

Leer-/ Abluggewichts (empty/takeoff weights) of G-6 through K-4, as per primary German datasheets from the war :

G-6 : 2268 kg / 3100 kg
G-10 : 2318 kg /3297 kg
K-4 : 2346 kg / 3362 kg

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).

Your figures are simply unreliable, again, my figures are based on primary German sources, and are reliable.

Maximum range of the 109F/G/K series was appx 1600 km (slight differences between variants), with a 300 liter droptank; 1000 km without; and economic cruise of ca 410-430 km/h; at maximum speed cruise, which means a rather high travel speed from 580 to as high as 645 km/h (K) yielded ca. 1000 km with a droptank. Now 400mph is a rather high speed, especially for cruising, some fighters in 1944 could hardly even hit it.

The 109K also had the possibility to use it`s rear fuselage tank as a rear aux fuel tank of 115 l capacity, ie. ca 25% greater internal fuel, but that ruled out MW 50 use.

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.

In other words, the differences are not particularly considerable; not even at altitudes where air combat is rather rare to happen, and here we are comparing low-production run stripped, hotrod P-47 sporting only six .50 guns IIRC. It`s a nice and faster aircraft than the rest at altitude, but it`s performance profile is somewhat hard to take advantage of, isn`t it? OTOH, I am not at all convinced of it`s manouveribility at high altitude. The P-47 is a very high wingloading aircraft, and figures I have for early models display the worst turn times of all WW2 fighters I`ve seen.

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.

Depends on what your target is - for heavy bombers, the 30mm armament is more appropriate. Interceptors are meant against bombers first and foremost.

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.

It seems to me the facts point to that the 109K was ready for operational service by October 1944, whereas the P-47M`s operational service was delayed by mechanical troubles, serious enough to call for grounding the fleet.

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.

Depends. The 109K had lenghty development, spanning over a year. When the 109K was introduced, it took a couple of weeks for the units to get them into combat after they`ve received it, but it appears to have coincided with a general rest&refit as the units were pulled from active duties in the period, so it doesn`t tell the full story. Otherwise, they just jumped in the seat and flew it like any other 109 - after all, it was just another 109, even if the latest, best, shiny and all that.

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.

I am sure that the Germans would have been able to push 'fully operational' the 109K by early 1944, which they have been developing from early 1943, if they would have been in deep **** by that time. BUT wait a minute, they were...

That`s too much of an assumption, as it ignores the simple fact that technical difficulties need time to be overcome, and this time won`t be any shorter if the troops are in a world of **** on the front.

The P-47M (wasn`t it stripped down to catch German jets and buzzbombs, ie. DS situation as above?), and for that matter, the P-80 prototypes were rushed into service, but rushing just doesn`t magically solves technical problems, on the contrary, it aggrevates them.

 

[HoHun]

Hi Davparlr,

>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.

If you look at the actual firepower in terms of total energy at the muzzle, you'll realize that the MK108 really was in a class of its own.

Here is the firepower per barrel comparison for the three weapon types we're looking at:

MK 108: 5.03 MW
MG 131: 0.21 MW
12.7 mm Browning M2: 0.28 MW

Total battery:

Me 109K-4: 5.45 MW
Eight-gun P-47D: 2.27 MW
Six-gun P-51D: 1.70 MW

(See also WORLD WAR 2 FIGHTER GUN EFFECTIVENESS )

The Me 109K-4 has the additional advantages of having centreline armament that leads to a high concentration of fire regardless of range, and of featuring weapons with a low dispersion, contributing to the concentration.

The US types on the other hand have the advantage of a higher muzzle velocity, which is helpful for hitting manoeuvering targets. The wing-mounted guns on the other hand introduced convergence/divergence effects that reduced concentration of fire considerably. (Not all US-types, of course - the P-38 did have nose-guns, and was often praised for its great gunnery characteristics.)

Here you can find summaries of two comparative Luftwaffe reports on armament:

http://www.ww2aircraft.net/forum/aviation/info-me262-big-gun-nose-2905.html#post297044

Note that the second report concludes that the low velocity MK 108 armament is superior over the high-veloctiy MK 103 + MG 151/15 armament at ranges up to 600 m even against hypothetical Mosquito-sized jet bombers.

Regards,

Henning (HoHun)