Corsair vs. BF 109G,K or FW 190's (4 Viewers)

[Crumpp]

Abnormal Configuration

If this doesn't clear problem,

If aircraft control is not an immediate concern

If touchdown speed exceeds 182 knots GS, consider further weight reductions

Fly using frontside approach characteristics (Pitch = GS, Throttles = Speed)

Use immediate and maximum available reverse thrust

Certainly the USAF includes emergency procedures in the event of a mechanical failure.

That is not the same thing as a design purposely having the slats fixed and then continuing to be operated.

All the best,

Crumpp

 

[Crumpp]

Off the top of my head in some Cessna 172s, 182s, the max flap extension was raised from 40 degrees to 30 degrees because of the possibility of "washing out the elevators in a slip."

TE flaps are being reduced. Not the same thing as LE slats being disabled for normal operation. Lets clear up the confusion here. I did not catch you refered to TE devices. Different characteristics and I would have specified so had I caught this.

There are many designs that do not have any flaps at all that operate safely. The point is however, that a design with LE devices cannot have the LE devices safely disabled and continue normal operations. The LE devices are there to achieve a design performance goal.

I've also seen 707s and DC-8s with limited or disabled slat/ slot/ flap systems flown during maintenance ferry flights.....

Certainly, they were being flown to a location in order to be fixed. Again not the same thing as being disabled for normal operation.

All the best,

Crumpp

 

[FLYBOYJ]

But the bottom line the aircraft shown can be flown and were flown under certain conditions and it would not be unreasonable to believe that in a combat situation and in a foward combat area an aircraft like the Lysander would operate with its LE slats closed due to maintenance limitations...

BTW I'm still searching for the article about the Lysander's LE slats being disabled....

 

[Kurfürst]

I got the info from this site which looks authentic including the identification of the aircraft number. In addition, two other sources I have and trust agree to the data shown in this flight test. The P-51D shows 375 mph at SL using about 1630 hp. I think my comments are good.

http://www.wwiiaircraftperformance.org/mustang/p51d-15342-level.jpg

Please see below.

The P-51D was introduced into the 8th AF in March '44. The Bf-109K was introduced in November, '44.

I am afraid this is incorrect, I trust Bill on this, and practically all publications I`ve seen say June 1944 for the P-51D as an introduction date.

The 109K was introduced in during October, units received it in huge numbers already that month (some 200 were around, even though some were wrecked during refit). It was certainly in combat by the start of November since the first combat loss is known from 2 November 1944.

So, if you want to keep the playing field truely even, you need to find the first date by which at least 200 P-51Ds were in service with first line units, and, they suffered losses in combat. For the 109K, it`s November 2, even though it was in production since August 1944.

To me a couple of months seems rather indifferent, and, there were plenty of 'interim' aircraft produced since early 1944 which ensured the 109K`s absance until October 1944 was not really felt - the K itself offered mostly just cleaner lines and more importantly, a standardized airframe with rationalized internal arrangements.

Six months in WWII during this time was a generation of aircraft development. In the summer and fall of 1944, a whole family of aircraft with much greater performance over the mainstay of WWII aircraft, was introduced on both sides. These include Fw-190D-9, Bf-109K, F4U-4, P-47M/N, P-51F (later H), Ta-152H, and others.

I think the 51F wasn`t introduced at all, or the p51H for that matter in the second half of 1944. I`d suggest you check out the new models of 109G that were introduced in the first half of 1944, especially the /AS types with methanol. By all accounts, these were excellent aircraft, and very close to the 109K in performance, albeit some 20 km/h slower due to their less clean airframes. Nevertheless, they stepped in for the 109K and DB605D since March 1944 as an interim solution.

The XP-51F, the predecessor of the H, flew in Feb. 44. Unlike Germany, who was desperate to stop the hordes of P-51s, P-47s, B-17s, B-24s, and Brit planes, with advanced aircraft, the US, whose aircraft performance was adequate and the quantity was overwhelming, did not expedite new models. Had the need arose, there is no doubt that a P-51H or the similar P-51F could have been available in the fall of '44.

There`s much speculation in this and grossly underestimates development problems. Germany, who was desperate to stop the hordes of P-51s, P-47s, B-17s, B-24s, and Brit planes, with advanced aircraft, as you say, was developing the 109K since March 1943. How much easy it would have been for them to have it, one may say, by late 1943...? It`s certainly very easy to say - but in It took them until late 1944 until it actually arrive at the units, and it was far less radical departure from the existing G-airframes. Not to mention, that to my best knowledge, the F-series Mustang, as hot their spec are, are essentially experiemental aircraft that toyed with the idea of lowering airframe stress limits and weight in favour for higher performance. Apart from it never been realized in this form, it`s also questionable how much use such lightly stressed aircraft would be operationally, how many potential problems would be needed to be solved with the airframe and engine before it would be combat ready, how long it would take factories to re-tool etc.

I don`t like such speculations, and after all, the facts are on the table, we know how it was, anything else is a swamp of guesswork, riddled with dangerous intellectual traps every step. The 51F did not become an operational type just and the P-51H, which just missed the war, eventually did not produce the very impressive performance figures originally expected and calculated for it.

My multiple sources show that the P-51D was capable of 375 mph at SL at about 1640 hp.

Individual aircraft performance of course, differ from plane to plane, and it especially seems to be true w the Mustang.

I prefer this one for the P-51D Performance since it notes that 'the data presented represent good agreement with most of the flight test results'. It`s probably a good middle-value.

It shows 368 mph at SL, and I presume the wingracks are missing (I could be wrong), which chopped some 12 mph off from top speed and were std fitting. With them it would do about 356 mph, and there`s also a test with the RAF`s TK 589 which I have which had 354mph at SL (w. racks).

The one you shown, with 375 mph claimed at SL at the same rating of 67", from June 1945, is very much higher than that. I can only guess why - perhaps an exceptionally good aircraft was tested, and/or it was polished and had special surface treatment. But I doubt it`s normal (and so do even North American, see above), it`s probably the best figure around.

The Bf-109K had 1800 horses available and could not achieve that (and my source for that is not Mike Williams site).

The 109K had 1800 PS in it`s earliest engine that was not fitted to too many aircraft though, or 1850 or 2000 PS. With the two latter ratings, it was officially rated at 370mph and 377 mph respectively, and some 8 mph if polishing was applied.

And of course, as in the case of the Mustang, there were worser and better planes. The tolerance was usually 3%, so theoretically you could have a production 109K anywhere between 360 mph (a plane w. the lowest rating, so badly built it just passed acceptance tests) and ~395 mph (a plane with the highest rating, with exceptionally good finish, polished by the loving groundcrew).

I don't know. While the data I referenced looks authentic and professional and states that it is flight test data (no tail numbers however), I have researched a lot and have not come up with support data for those values. Since I do not like depending on sole source data, especially when other data is available, I must withdraw my comments referencing F4U-4 climb rates.

That`s what puzzles me. I have seen half a dozen set of data for the the F4U4, and none of them agree. It seems they were continously revised, for some reason.

Unfortunately, I do not have any data from you on climb for the Bf-109K, so the only data I could use was from Mike Williams site and this particular data (but not most at Mike's site) may be a bit suspect. I would be glad to update my data base to better data if you could give it to me.

You may find this kind of climb rate data (copies of the original papers) on my site, for both 1,8 and 1,98ata. Mike used to have 1,98ata performance displayed, ableit barely visibly on some previous version of his controversial comparison articles, but appearantly he couldn`t bear it even being there so he removed it a while ago. It seems some of his current values for the K-4 at 1.8ata are in fact taken from the K-6 heavy fighter.

In any case you can view the whole thing on my site, here : Kurfürst - Performance of 8 - 109 K4 and K6 with DB 605 ASCM/DCM This is the only thing, I dare say, most if not all of us aircraft geeks have on 109K performance.

 

[Crumpp]

But the bottom line the aircraft shown can be flown and were flown under certain conditions and it would not be unreasonable to believe that in a combat situation and in a foward combat area an aircraft like the Lysander would operate with its LE slats closed due to maintenance limitations...

For a single incident on a one time maintenance flight to be repaired. Maybe...

As for continuing normal operations, no way.

Nothing you have shown has any aircraft continuing to operate normally.

I've also seen 707s and DC-8s with limited or disabled slat/ slot/ flap systems flown during maintenance ferry flights.....

Do you know for a fact the LE slats were disabled on these?

You are pilot correct? Have you made many frontside curve approaches?


All the best,

Crumpp

 

[FLYBOYJ]

For a single incident on a one time maintenance flight to be repaired. Maybe...

As for continuing normal operations, no way.

Nothing you have shown has any aircraft continuing to operate normally.

From an earlier post - ironically it was another Westland Product..

Page 47 of 'Whirlwind' by Victor Bingham-1987

Do you know for a fact the LE slats were disabled on these?

Yes, ferry flights out of Mojave Ca on aircraft removed from storage. Not the norm however.....

You are pilot correct? Have you made many frontside curve approaches?

If you want to include short field landings in a Super Cub!?!?

 

[Soren]

Crumpp,

What would the sustained load factor be for the Fw-190 A-5 by comparison to the A-8 ?

 

[Crumpp]

If you want to include short field landings in a Super Cub!?!?

You can't be on the frontside of the curve in a Super Cub and make a short flield landing. You would be dead.

You are probably confusing terms here as I do not doubt your experience in a Cub.

Page 47 of 'Whirlwind' by Victor Bingham-1987

That would be a first. As it is this second hand information and not a primary source, I would be interested in seeing the Boscume Down reports. It would not be the first time a secondary source is wrong in it's conclusions.

All the best,

Crumpp

 

[FLYBOYJ]

You can't be on the frontside of the curve in a Super Cub and make a short flield landing. You would be dead.

You are probably confusing terms here as I do not doubt your experience in a Cub.

I take your term as being on the front side of the curve as having both power and airspeed in a landing configuration....

 

[Crumpp]

What would the sustained load factor be for the Fw-190 A-5 by comparison to the A-8 ?

It is worse than the FW-190A8's.

The P51D has a slight advantage over the FW-190A5 throughout the envelope.

Nzmax is a direct reflection of Power Available to Power Required. The FW-190A8 has a better P/W ratio than the FW-190A5.

FW-190A5 Take Off Weight as per Ladeplan for an overloaded clean configuration fighter:

I take your term as being on the front side of the curve as having both power and airspeed in a landing configuration....

We are confusing terms here.

The front side of the power curve refers to the portion of the flight envelope where throttle controls airspeed and elevator controls altitude. We can only use the term "power curve" when referring to propeller aircraft.

This is also called the region of normal command. In this portion if we go slower, it requires less thrust and to go faster requires more thrust. Think of operating the aircraft at speeds at or faster than maximum range cruise or L/Dmax.

You can see why landing of the front side of the power curve is not normal or safe. You can also see why the C-17 manual calls for maximum braking and reverse thrust ASAP.

The backside of the power curve is the portion where throttle controls altitude and elevator controls airspeed such as landing.

This is also called the Region of reversed command. If for any reason, the aircraft is slowed down, more thrust is required to maintain altitude. Here going slower requires more thrust and going faster less thrust. Notice on landing that reducing thrust causes our sink rate to increase. Sink rate is velocity. The airplane needs this speed to remain aloft. However it takes a large amount of power to maintain level flight at approach speeds.

Because propeller aircraft are not thrust limited at low velocity, they can lead pilots to the wrong conclusions about what is going on with aircraft.

All the best,

Crumpp

 

[delcyros]

I think this has been a good discussion so far. And my estimation is that we all have learned a bit.

Good work Crumpp for providing us with an approach to sustained turning rates free from personal objection. I hope You stay with us.

I think Glider, Kurfürst and others have pointed us to a very important constraint: typical performance vs. best (or for that matter...worst) aircraft performance.
There are a lot of first hand sources in those webpages, and selective perception may happen on all sides.

Thanks also to Drdondog, You are a wealth of information!

 

[FLYBOYJ]

We are confusing terms here.

The front side of the power curve refers to the portion of the flight envelope where throttle controls airspeed and elevator controls altitude. We can only use the term "power curve" when referring to propeller aircraft.

This is also called the region of normal command. In this portion if we go slower, it requires less thrust and to go faster requires more thrust. Think of operating the aircraft at speeds at or faster than maximum range cruise or L/Dmax.

You can see why landing of the front side of the power curve is not normal or safe. You can also see why the C-17 manual calls for maximum braking and reverse thrust ASAP.

The backside of the power curve is the portion where throttle controls altitude and elevator controls airspeed such as landing.

This is also called the Region of reversed command. If for any reason, the aircraft is slowed down, more thrust is required to maintain altitude. Here going slower requires more thrust and going faster less thrust. Notice on landing that reducing thrust causes our sink rate to increase. Sink rate is velocity. The airplane needs this speed to remain aloft. However it takes a large amount of power to maintain level flight at approach speeds.

Because propeller aircraft are not thrust limited at low velocity, they can lead pilots to the wrong conclusions about what is going on with aircraft.

All the best,

Crumpp

Ok - I think I Gotcha - you're on final (say in a cub, no wind) nose high and using power to control pitch - if you lack the airspeed, you drop, if you lack the power you drop BUT if you had altitude you could lower the nose to pick up that precious airspeed without increasing power - am I understanding?

 

[Soren]

Thank you Crumpp, but is that with the A-5 running at 1.65ata ?

The A-5 weighed in at 4,100 kg and the A-8 4,300 kg, correct ?

PS: The LW deployed a light version of the A-7 with MW-50, how would that compare ?

 

[Crumpp]

Ok - I think I Gotcha - you're on final (say in a cub, no wind) nose high and using power to control pitch - if you lack the airspeed, you drop, if you lack the power you drop BUT if you had altitude you could lower the nose to pick up that precious airspeed without increasing power - am I understanding?

Hi FlyboyJ,

In this example you are on the backside of the power curve. You are using elevator to control airspeed and throttle to control sink rate.

That is a clear indicator you are on the backside.

Thank you Crumpp, but is that with the A-5 running at 1.65ata ?

Hi Soren,

No it is normal fighter variant. There were not any fighter variants that used 1.65ata in any form for the FW-190A5.

The A-5 weighed in at 4,100 kg and the A-8 4,300 kg, correct ?

FW-190A8 - 4272Kg
FW-190A5 - 4106Kg

The LW deployed a light version of the A-7 with MW-50, how would that compare ?
Today 04:49 PM

I am not aware of this variant and none of Focke Wulfs documentation show such a variant.

MW-50 was used in the H and S series engines. Very late in the war it possibly was used in the BMW801D2 series. Alkohol-Einsptrizung systems produced less power and required the additional weight of the tank over other systems used by BMW.

All the best,

Crumpp

 

[FLYBOYJ]

Hi FlyboyJ,

In this example you are on the backside of the power curve. You are using elevator to control airspeed and throttle to control sink rate.

That is a clear indicator you are on the backside.

Now I gotcha!

Sorry to go off topic guys......

 

[Crumpp]

I think Glider, Kurfürst and others have pointed us to a very important constraint: typical performance vs. best (or for that matter...worst) aircraft performance.

Thank you, delcyros. I enjoy these discussions with mature individuals.

I agree that typical performance is very important.

All the best,

Crumpp

 

[renrich]

My reference show the P51 D with a sea level vmax of 367 mph, the P51B was slightly faster at SL. The F4U 4 was fastest of all at SL(US fighters) with Vmax of 380 mph. Same reference shows the P51D is introduced into the 8th AF in March of 1944. Same reference shows F4U4 could climb to 20000 ft in 6.8 minutes. Another reference shows the FW190D9 took 7min 6sec to climb to 19685 ft. The F4U4 was a significantly better climber.

 

[FLYBOYJ]

Hi FlyboyJ,

In this example you are on the backside of the power curve. You are using elevator to control airspeed and throttle to control sink rate.

That is a clear indicator you are on the backside.

Hey Crumpp;

In answering your original question about this - I've flown L-29s and on landing you are controlling sink rate with elevator because of the spool-up time of the engine and because of a very long flare if you do come in with power at that point you rely on the speed brake providing you're not on a short field...

OK guys, again sorry for going off topic....

 

[Glider]

Personally I enjoyed it and continue to learn something in most threads

 

[DerAdlerIstGelandet]

OK guys, again sorry for going off topic....

Hey Joe you know you dont have to apologize. It is a good and informative side discussion. I think everyone can gain from it as well.