Crummp- a new thread for old issues

[F4UDOA]

Crummp,

I wanted to respond to some of your comments I found surprising in the FW190 VRS F8F thread.

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You can improve it marginally with superior power loading but high wingloading is hard to overcome unless you are flying a stunt plane.
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You responded to my comment with.

Does a stunt plane use different physics? It is not nearly as hard as you think to overcome. In fact wing loading is not very good for determining turning ability except in the most general of terms.

Increasing thrust reduces radius by allowing a larger angle of bank. Even though the Spitfire gained 1000lbs, a relatively small power increase was more than able to compensate. The FW-190 gained as much power and much less weight than the entire series of Spitfires used during the war.

I completely disagree with your analogy based on my brief research of stunt aircraft and their characteristics. I used the Suhkoi SU-26 as my test aircraft because Suhkoi makes the best Aerobatic aircraft in the world and the numbers are readily available.




Category Unlimited single-seater
Length 6.83 m
Wingspan 7.80 m
Wing aera 10.83 m2
Empty mass 720 kg
Engine Vedeneyev M14P, nine-cylinders radial
360
Hp
Propeller 3 blade constant-speed
Span : 2.54
m
Max speed 450 Km/h
Stall speed 110 Km/h
Roll rate 400 °/s
Max acceleration +12 / -8 g


Actually I think my Stunt/Aerobatic plane analogy works well if you look at the critical indicators

1. Power loading empty weight
1587lbs / 360HP = 4.4

Wing Loading
1587LBS / 116Sqft = 13.6

The power loading is worse than a F6F while the wing loading is astronomically low. So what is import factor in high AOA manuevers? Wing loading or power loading?

For comparison

FW190A-5
Power loading
Basic Weight = 6716LBS
Power Loading
6716LBS / 1755HP = 3.82
Wing Loading
6716LBS / 197Sqft = 34.09

The FW190 Has better power loading but I wouldn't want to try to outturn the Suhkoi.

Also you posted this as part of your proof of theory. I have a couple of good books on Aerodynamics and I have worked hard to learn some basic calculations to help me fill in the blanks but I do not know what I am to take out of this.



Lastly you made this reponse to the problems caused by sabotage and poor workmanship due to the use of slave labor.

Got to call a BS flag on this one F4UDOA.

While sabotage and poor quality control did effect German production it had little effect on the frontline Geschwaders until the system breakdowns in the last months of the war.

Just like the allies, the aircraft were inspected and had to perform during a check out flight before being accepted by the Luftwaffe for service.

Only in terms of supply would this be an issue, not performance.

Now there is one outstanding exception. Oil formulation appears to have been sabotaged in 1943. The Luftwaffe lost almost 500 801 motors in one year because one man changed the formula causing the oil to breakdown at high tempatures. This cause broken rods. The cause was found, the formula fixed, and the poor guy is listed as "no longer working" in oil production.

Some other instances of "sabotage" did occur. For example an entire Staffle is listed in one Beanstandungen as being "sabotaged" when they cracked cylinders in two motors in a month. The Kommandogerät jets were drilled allowing the motor to run at 1.8ata using Erhöhte Notleistung. In a military service were destruction of state property could carry the death penalty, I would list the mechanics tinkering as "sabotage" too if I was the pilot benefiting. Focke Wulf and BMW conducted a study and determined the practice was dangerous. Geschwaders were ordered to cease the modification.

The chances of a sabotaged motor or aircraft reaching the Geschwaders was pretty remote.

This quote from a Luftwaffe pilot would seem to indicate that the problems did reach the field. The quote is in regard to the 109G-14 showing up with various problems from poor workmanship to wires being cut. The Pilot Hans Knickrehm is from JG/3. However it is copyright material so I cannot cut and paste.

Here is the page

http://64.233.167.104/search?q=cache:Ad_IuiD6WPQJ:[url]www.spitfireperformance.com/spit14v109.html+fw+190+sabotage&hl=en[/url]

You also mention that the perpatraitors were subject to the death penalty if caught. You realize that the workers in these factories were already sentenced to death?

[justin_g]

The reduction of turn radius with increased power is relatively small, the major improvement is in the turn RATE. This is obvious when you look at an E-M diagram, such as the ones found in this thread: http://www.hitechcreations.com/forums/showthread.php?s=&threadid=132948

Looking at those EM charts - even if you could have enough power to pull 6G in a sustained turn, the turn radius would only decrease by about 10-15%, while the turn RATE would be almost doubled!

[F4UDOA]

Absolutely,

Turn rate increases but the radius does not get affected very much(relatively). Especially when the difference in power loading is marginal. If you know the HP, Wing area, top speed at sealevel and 1G stall speed there is very little to the imagination at that point.

I have a good spread sheet that shows this very clearly at various G loads.

[F4UDOA]

I need to rephrase a little bit.

The airflow over the wing will reduce stall speed very much by the application of even a little power. However in relation to another aircraft with significantly superior wingloading this will by itself not be enough to overcome the deficit in turn radius IMHO.

[Crumpp]

The airflow over the wing will reduce stall speed very much by the application of even a little power. However in relation to another aircraft with significantly superior wingloading this will by itself not be enough to overcome the deficit in turn radius IMHO.

That is a pretty good generalization and would be correct.  The Spifire Mk XIV for example was able to overcome a 5lb per sq ft wingloading increase over the Spitfire Mk IX by having more thrust.

This is why the Dora outturns the FW-190A8.  It has the same wingloading by more efficient propeller and more power.  The FW-190A8 turned as well if not better than the FW-190A3.  The FW-190A8 has significantly more power and a more efficient propeller than the FW-190A3.

The wingloading at Fluggewicht for a full wing armament fighter variants only increases 3-4 lbs from the FW-190A3 to the FW-190A8.

FW-190A3 - 3978kg

FW-190A8 - 4272kg

Turn rate increases but the radius does not get affected very much. Especially when the difference in power loading is marginal. If you know the HP, Wing area, top speed at sealevel and 1G stall speed there is very little to the imagination at that point.

justin_g very nicely explained how better powerloading increases an aircraft turning ability.

F4UDOA says:

This quote from a Luftwaffe pilot would seem to indicate that the problems did reach the field.

Crumpp says:

While sabotage and poor quality control did effect German production it had little effect on the frontline Geschwaders until the system breakdowns in the last months of the war.

Big Difference in what I said and what you are taking it to mean.

All the best,

Crumpp

[F4UDOA]

Crummp,

I believe the A3 was the best overall dogfighter of the bunch.

I do not believe the Spit XIV could turn as well as the Spit IX the same way I don't believe the A8 could turn as well as the A3. They both trade turn radius for rate. I don't think they got them very slow when they were testing.

The only tactic that could be employed would be using their speed advantage combined with climb rate to b&z.

The A6M2/5 was probably the best turning of the major A/C types of the war but it had very modest power loading. By contrast a LA-7 could never out turn it but could definitely fly very fast circles around it.

The P-47D-5 specified in the trial against the FW190A-5 actually had worse wing loading but most likely had better power loading at high alts and yet at low speed the 190 still out turned it.

FYI, The AAF evaluation of the FW190D-9 says that they preffered the Anton because it handled so much better.

[Crumpp]

I do not believe the Spit XIV could turn as well as the Spit IX They both trade turn radius for rate.

Decrease turn radius and you increase turn rate, F4UDOA.  You can believe it or not but it remains a fact.

Power on stall will also improve when thrust is added.  You have increased thrust to overcome drag.

The RAE tested the Spitfire Mik XIV and the conclusions are available to all.  Once more these results are very much backed up by science.

The all-round performance of the Spitfire XIV is better than the Spitfire IX at all heights. In level flight it is 25-35 m.p.h. faster and has a correspondingly greater rate of climb. Its manoeuvrability is as good as a Spitfire IX. It is easy to fly but should be handled with care when taxying and taking off.

The turning circles of both aircraft are identical.

http://www.spitfireperformance.com/spit14afdu.html

the same way I don't believe the A8 could turn as well as the A3.

Why wouldn't it?  

Adding thrust increases lift.

 

 


The Focke Wulf gained less weight and just as much power as the Spitfire.  It gained less weight and more power than many allied designs.  It also gained several propeller upgrades increasing the efficiency.  In fact the design used 5 different metal props and two different wooden ones during it's design lifetime.

Do you have facts or just beliefs on this?

I don't think they got them very slow when they were testing.

The power off stall speed of the Spitfire Mk IX was probably lower than the Spitfire Mk XIV.  However combat pilots are not using power off stall.  They are flying with power on.

With increased thrust, the Spitfire Mk XIV was able to overcome a 1000lb weight increase and a 5lb sq ft wingloading increase.  It simply was able to pull a larger angle of bank at the same speed than the Spitfire Mk IX.  This reduced the turn radius, increased the turn rate, and allowed it to match the much lower wingloading of the Spitfire Mk IX.

 

However in relation to another aircraft with significantly superior wingloading this will by itself not be enough to overcome the deficit in turn radius IMHO.

Your statement remains true if the wingloading difference is significant.  A few lbs increase can be overcome with thrust.

All the best,

Crumpp

[Crumpp]

The AAF evaluation of the FW190D-9 says that they preffered the Anton because it handled so much better.

FYI,

I would trust the Luftwaffe FW-190 Geschwader pilots who had significant experience in both over an unknown condition Dora.

Additionally, depending on the Dora, this could very well be the case.  The first production Dora's did not represent a major thrust increase.  Once the Oldenburg system and Junkers team modified the Jumo 213's things were different.

All the best,

Crumpp

[Kurfürst]

Originally posted by F4UDOA

This quote from a Luftwaffe pilot would seem to indicate that the problems did reach the field. The quote is in regard to the 109G-14 showing up with various problems from poor workmanship to wires being cut. The Pilot Hans Knickrehm is from JG/3. However it is copyright material so I cannot cut and paste.

Here is the page

http://64.233.167.104/search?q=cache:Ad_IuiD6WPQJ:[url]www.spitfireperformance.com/spit14v109.html+fw+190+sabotage&hl=en[/url]

You also mention that the perpatraitors were subject to the death penalty if caught. You realize that the workers in these factories were already sentenced to death?

F4U, I guess we all know the reason why this site has these selective pickings with strong bias and the habit of forgetting the big picture. Sure, Knickrehm got a poorly made plane, he was unlucky. But what does that prove? One can generally find qoutes for a claim and qoutes showin the opposite. They are exceptions to the rule. I can find you qoute from Caldwell's JG 26 diary of a JG 26 pilot prasing the quality of his Dora-9 built in Sorau. One can find individual examples of both good and poor production quality, so what do we learn, that production planes varied in quality? That was the same everywhere, that's why there was an acceptance tolerance on performance of production aircraft. We know Williams and his site, and what his agenda is, thus we know why that qoute was put there. Looking through his articles, my impression is that there are tons and tons and tons of refernces to bad things on the LW side for which even the remote possibility of competitive performance must be dismissed, and nothing, zero, nada concenrs for his 'own' side. Oh I am quite sure it was that black and white [sarcasm on]!

The big picture from what I learned is quite different. Even the American reports done immidiately post-war (I refer to USSBS) admit the quality was quite well kept up regarding the items that defined performance, and the report goes into details praising the BAL's rigorous standards up to the end of the war. The authors go as far stating they could swap planes with the LW (and apart from range issues) still beat them not because of the quality of planes, which was seen equal, but the pilots.

Also I have 1945 april (i think) interview with a Me 262 accaptence test pilot. He states that practically all planes he tested satisfied the performance tolerance. That says it all, regardless of the rather transparent personal agenda from the creators of spitfireperformance.com. BTW, I am to take a site seriously that claims a certain boost was not cleared, and shows as 'evidence' the ratings of another engine? Doh.

[MiloMorai]

Barbi, you are like the bull when seeing red > ignores all else.

Mike says that his performance curves should be treated with reserve.

I am to take a site seriously that claims a certain boost was not cleared

He says: The DB605DC at 1.98ata with  MW was tested but seems not to to have made it into service.

It was not just Knickrehm's a/c, for he says more than one a/c received by his unit.

Kindly try to improve your reading comprehension skills.

[F4UDOA]

Kurfurst,

Is your assertion that the possibility that slave (Slave being a kind term in this case) labor might want to do less than a perfect job or even want to "sabotage" the very people that were trying to kill them?

Are you saying that they had the same vigilence in there effort than say a worker at Grumman, North American or Supermarine who might have a family mamber who life depended on the quality of their work?

What ever problems you have with Mike Williams are your own, the quote came from a member of the Luftwaffe who described multplie problems not one incedent.

[Crumpp]

German quality control problems had more to do with expanding their industrial base than slave labor.

The skilled workers were not the slaves either.

Examine so companies just dealing with expansion:

n January 1943 the government’s War Production Board officially criticized Willow Run’s performance for the first time. The factory’s primary problem, according to the board, was a shortage of manpower, the plant found it difficult to hire and keep competent workers.

What were all those loyal workers doing?

At the same time, it was reported that "the automotive type precision tooling at Willow Run had resulted in such uniformity of production that more than half of all of the Ford-built Liberators were accepted for delivery on their maiden flights," an unusually high percentage of plane approval.

Who was sabotaging the other 50 Percent that did not make it?

. Willow Run did not produce a plane until July 1942, and that one was a knockdown sent to a Douglas Aircraft assembly plant in Tulsa, Oklahoma. The first flyaway was not turned over to the United States Army until September 10, 1942.

During the last few months of 1943, as the giant plant began living up to its press notices of 1941 and the first half of 1942, the threat of a government takeover faded.

Over a year to begin producing some quality planes?

http://www.michiganhistorymagazine.com/extra/willow_run/willow_run.html

All the best,

Crumpp

[Crumpp]

The aeronautical science questions are answered on how increasing power available can overcome a small wingloading increase thereby improving turn performance.

This thread is done then as it is moving on to other subjects.

I believe the A3 was the best overall dogfighter of the bunch.

You can believe that if you wish.  However, the pilots who flew the FW-190A, the facts, and the science point to a different conclusion.

The P-47D-5 specified in the trial against the FW190A-5 actually had worse wing loading but most likely had better power loading at high alts and yet at low speed the 190 still out turned it.

At high altitudes, where the P 47 does have better powerloading the P47 easily outturned the FW-190A5.  The FW-190A5 recieved only the penalty of increased wingloading with no power gains over the earlier FW-190A's.  All the Focke Wulf pilots agree it was the worst performing variant.

All the best,

Crumpp

[justin_g]

Power on stall will also improve when thrust is added. You have increased thrust to overcome drag.

Not really how it works. Adding some propellor thrust at the low airspeed of a 1G stall has the effect of increasing the local velocity of the air moving over the wing in the propwash, which provides an increase in lift.

However, only a small amount of engine power is required for this effect, and adding more after that gives extremely diminishing returns. For example the NACA tested the Spitfire V stall in several conditions:

Stalling speeds, clean condition

Glide(engine off) = 90mph
Cruise(2650rpm, +3.75lbs) = 77mph
Climbing(2850rpm, +7lbs) = 76mph

Also this effect will be greatly reduced at higher speeds, where the thrust from the propellor will become less and less. So adding power in a sustained turn will not increase the lift of the wing in that way.


What is true is that increased power will allow the aircraft to overcome more drag, allowing the aircraft to fly at a higher speed(and G load) in a sustained turn. So you keep turning almost the same radius, but at a faster speed which increases the turn rate.

This can be easily seen on the EM diagrams. The only way to significantly reduce turn radius is to fly near corner velocity(6G stall speed). The only way to be able to sustain that speed is to have more power - ALOT more power. But only moderate increases in power will result in noticable improvement in sustained turn RATE, with the turn radius being reduced by only a tiny amount.

[Crumpp]

Adding some propellor thrust at the low airspeed of a 1G stall has the effect of increasing the local velocity of the air moving over the wing in the propwash, which provides an increase in lift.

Your correct in your statement but I think your refering to fin thrust.

http://naca.larc.nasa.gov/reports/1944/naca-wr-l-25/naca-wr-l-25.pdf

Which is an aircraft stability issue linked to propeller design.

Perkins & Hage says turning is a fundamental relationship of thrust required and power available for an airplane at various angles of bank.
 

Adding thrust allows an aircraft to pull a sharper angle of bank reducing the radius and increasing the rate.
 

All the best,

Crumpp