Corsair vs. BF 109G,K or FW 190's

[Kurfürst]

Originally Posted by Glider

This would imply to me that it was a more common problem on the 109 as this was a general warning issued to all units.
I am not aware of similar warnings being sent to all Spitfire or P51 units.

Certainly I could be wrong on this and if anyone has a similar warning issued to allied units, I am happy to change my view.

... that`s a faulty conclusion based on insufficent information. We know there was an instruction for the 109F wingtips. Do we know the 109G still had this problem? How we do the Mustang and Spitfire (La7, Yak3, Typhoon etc.) did not have similiar problems? They are less well documented? Of course. The less details we dig up on a plane, the fewer skeletons we find in the cupboard. But that doesn`t effect the actual number of skeletons overall. They are there, even if we don`t know about it.

BTW, ever wondered why the 'pointed', ie. tall vertical stabiliser was introduced to the Spitfire..? Stabiliser fin to the p51d..? Tall tail to the 109?

These aircraft had more in common than not. Designers kept bumping into the same limits, no matter the country. Physics are universal.

[drgondog]

Originally Posted by Soren

Exactly at what alt is this Bill and from where do you have this ??

The reason I'm asking is because the official figures are much higher.

This is from the POH:


"Official" ??

As you can see the P-51D's stall speed in level flight was around 106 mph clean.

at 10,000 feet, 96 at 8,000 close to 80 at SL

I don't have the official figure for the FW-190, I was hoping Crumpp would provide that, my guess is its lower though, esp. considering the much shorter take off run and distance to clear a 20m high object.

Page 29 of the "Pilot's Flight Operating Instructions AN 01-60JD-1" has the reference to Zero Sink speed - clean.

Multiple references are made to this including the instruction to not start climb until flaps are up and airspeed at least 110IAS... and do not side .slip the Mustang below 110 IAS, etc..

Stall speed is contained in Appendix II and varies with load but I have flown the airplane several times at 80-90 mph at 5000 feet to coax it into a clean stall, notably because my dad 'insisted' that I learn how easy it is to recover from. The bird would have weighed in the 8900+ weight range.

You were looking at 106mph/10,000 feet in your Power Off Stall chart and failed to notice (?) that the stall speed in that chart was down to 94 mph for 8,000 feet and continues to drop with increased density.

Crumpp's figures are`'correct' for good assumptions in performance calculations.

[drgondog]

Originally Posted by Crumpp

The Center of Lift is located at the main wing spar in the Bf-109G. I can send you the ladeplan and the Ersatzteilliste. You might be thinking of the rearward CG limit. Remember that has to be just forward CoL if we want a controllable aircraft.

All the best,

Crumpp

Crumpp - ??

I made an assumption based on drawings I have seen of the 109 that the main spar is around 45% chord - not so? or, just as intriguing the Center of Lift actually at 45%??

[drgondog]

Originally Posted by Kurfürst

... that`s a faulty conclusion based on insufficent information. We know there was an instruction for the 109F wingtips. Do we know the 109G still had this problem? How we do the Mustang and Spitfire (La7, Yak3, Typhoon etc.) did not have similiar problems? They are less well documented? Of course. The less details we dig up on a plane, the fewer skeletons we find in the cupboard. But that doesn`t effect the actual number of skeletons overall. They are there, even if we don`t know about it.

BTW, ever wondered why the 'pointed', ie. tall vertical stabiliser was introduced to the Spitfire..? Stabiliser fin to the p51d..? Tall tail to the 109?

These aircraft had more in common than not. Designers kept bumping into the same limits, no matter the country. Physics are universal.

There were no wintip issues with 51 or control reversal issues due to aileron loads causing too much twist in wing.

Having said this, the P-51 had sveral 'skeletons', all were well documented and none remain as skeletons... as you (and Crumpp) said - they all had problems and all were fixed.

The big ones for the 51 were a.) wheel door uplock failing to keep landing gear where it belonged in a dive, b.) bad batch of heat treated bolts for engine mounts, c.) increasing yaw as speeds increased from .75 to .81 Mach, d.) structural failure of Tail/aft fuselage due to asymmetrical loads at high speeds (i.e rolling in dive, snap roll at high speed), e.) ammo door deflection at high speeds causing a local increased lift and spar failure in high speed diving pullout.

To the best of my knowledge Kurfurst, there is no conspiracy to keep those shameful secrets hidden?

[Soren]

Originally Posted by drgondog

Page 29 of the "Pilot's Flight Operating Instructions AN 01-60JD-1" has the reference to Zero Sink speed - clean.

Multiple references are made to this including the instruction to not start climb until flaps are up and airspeed at least 110IAS... and do not side .slip the Mustang below 110 IAS, etc..

Stall speed is contained in Appendix II and varies with load but I have flown the airplane several times at 80-90 mph at 5000 feet to coax it into a clean stall, notably because my dad 'insisted' that I learn how easy it is to recover from. The bird would have weighed in the 8900+ weight range.

You were looking at 106mph/10,000 feet in your Power Off Stall chart and failed to notice (?) that the stall speed in that chart was down to 94 mph for 8,000 feet and continues to drop with increased density.

Crumpp's figures are`'correct' for good assumptions in performance calculations.

What are you talking about Bill ??!

The stall speeds are given for different weights, NOT different altitudes!

What the chart says is that the P-51D stalls at 106 mph at SL at 9,700 lbs ! At 10,000 lbs its 108 mph at SL. There's no way the P-51D is ever going to fly at 80 mph clean, the real stalling speed is WAY higher than that!

Btw, is it me or are you saying you actually fly the P-51 ?? - suspiciously late to come forth with this IMO.

[Crumpp]

Btw, is it me or are you saying you actually fly the P-51 ?? - suspiciously late to come forth with this IMO.

When your father is a P51 Ace, you think he might take you flying?

All the best,

Crumpp

[drgondog]

Originally Posted by Soren

What are you talking about Bill ??!

The stall speeds are given for different weights, NOT different altitudes!

What the chart says is that the P-51D stalls at 106 mph at SL at 9,700 lbs ! At 10,000 lbs its 108 mph at SL. There's no way the P-51D is ever going to fly at 80 mph clean, the real stalling speed is WAY higher than that!

Btw, is it me or are you saying you actually fly the P-51 ?? - suspiciously late to come forth with this IMO.

You are right about the chart Soren - I was braindead on the quick glance at your chart.

As to a/c command time in the 51 - You haven't been paying attention. You have made more than a few 'not true comments' that I corrected based on my own experience with the ship. I have also commented that my own experience with cross wind landings does not co-incide with Manual just because it has a wide track gear!

I have 100 dual and 56.6 solo in a P1D-25 and -30.. I think I first mentioned it in June timeframe in a conversation with Joe about preferred landing speeds (I favored 110+ IAS Power on at 2700 rpm and 15-20 degrees flaps depending on how fast I wanted the sink rate.)

And Crumpp is correct on stalling speeds although I am reasonably sure he is talking about a bird at near max gross or at least combat load.- and yes the 51 stall speed for 8000-8500 pounds is somewhere in the range of 80-90 mph clean, power on, depending on a lot of factors... but much less than 110 IAS.

[drgondog]

Originally Posted by Crumpp

When your father is a P51 Ace, you think he might take you flying?

All the best,

Crumpp

G - LOL - I'll tell You the story -it's worth it. Via email. The net is "there's nothing wrong with a fix - if you are in on it"

The USAF auctioned a lot of 51's when they got out of the biz in 1957-1958 and dad bought one.

He got a 51D-25 that had been completely overhauled, and included a spare 1650-7 with less than 25hrs on it. He traded that to Cavalier in return for a two seat TF-51D conversion..

He was one hell of a fighter pilot but perhaps an even better instructor. I miss him still and it's been 28 years.

My last time in the bird was back in 1985. If I was a biilionaire I would buy off the FAA docs and have one today.

Regards,

Bill

PS - both Jeff Ethell and I got our pilot's license before we got a driver's license - go figure. And Jeff's dad Irv was a squadron CO when my father was Gp CO of 35th in Japan - we grew up together, starting in Japan in 1948 - and I miss him.

[Crumpp]

I made an assumption based on drawings I have seen of the 109 that the main spar is around 45% chord - not so? or, just as intriguing the Center of Lift actually at 45%??

Hi Bill,

The AC has to be forward of the CG as you know. The limits of the CG are measured from Bulkhead 1 not from the LE of the wing. The main spar is located 1003.2mm from the LE and the most rearward CG location on the Bf-109G2 is 69.2cm from Bulkhead 1 <firewall>.

As you know, the most rearward portion of the CG has to in front of AC. The AC is in the vicinity of the spar were it should be as far as I can tell.

So I am not confusing you. Center of Lift and Aerodynamic Center are interchangeable terms today. You are probably used to Center of Pressure calcs where M = Lx.

Center of Pressure is seldom used today. The math gets hokey. As we approach zero lift mathematically our x reaches infinity and the Cp moves backward to infinity. This is of course impossible. You’re probably thinking Cp is Center of Lift instead of AC. It used to be when we did Cp calcs.

AC is the point where all the torques of the Aerodynamic Forces are located.

To Soren’s credit, Bill, there are plenty of folks who prowl these kinds of boards whose sole motivation is to up their game score and live out their ace fantasy. There is more than one BS artist around.

So readers will be able to follow what we are discussing.

Aerodynamic Center

All the best,

Crumpp

[drgondog]

Originally Posted by drgondog

Page 29 of the "Pilot's Flight Operating Instructions AN 01-60JD-1" has the reference to Zero Sink speed - clean.

Multiple references are made to this including the instruction to not start climb until flaps are up and airspeed at least 110IAS... and do not side .slip the Mustang below 110 IAS, etc..

Stall speed is contained in Appendix II and varies with load but I have flown the airplane several times at 80-90 mph at 5000 feet to coax it into a clean stall, notably because my dad 'insisted' that I learn how easy it is to recover from. The bird would have weighed in the 8900+ weight range.

You were looking at 106mph/10,000 feet in your Power Off Stall chart and failed to notice (?) that the stall speed in that chart was down to 94 mph for 8,000 feet and continues to drop with increased density.

(Wrong - I misread the chart - each condition for stall i power Off and different gross weights - called a brain fart on my part
Crumpp's figures are`'correct' for good assumptions in performance calculations.

correction made as noted

[16KJV11]

Originally Posted by Soren

Hehe 127 mph is not the stall speed, the landing speed was lower than that. The stall speed of the P-51D with flaps and gear retracted is 109 mph IIRC, and the FW-190 around 102 - 105 mph under the same conditions.

Like I said, "For what it's worth".

[FLYBOYJ]

Originally Posted by Soren

Btw, is it me or are you saying you actually fly the P-51 ?? - suspiciously late to come forth with this IMO.

Bill has stated on several occasions that he and his dad flew in P-51s.(together)

[FLYBOYJ]

Originally Posted by drgondog

both Jeff Ethell and I got our pilot's license before we got a driver's license - go figure. And Jeff's dad Irv was a squadron CO when my father was Gp CO of 35th in Japan - we grew up together, starting in Japan in 1948 - and I miss him.

I always enjoyed his books and seeing him on the history channel. I was deeply saddened when he was killed...

[Glider]

Originally Posted by Kurfürst

... that`s a faulty conclusion based on insufficent information. We know there was an instruction for the 109F wingtips. Do we know the 109G still had this problem? How we do the Mustang and Spitfire (La7, Yak3, Typhoon etc.) did not have similiar problems? They are less well documented? Of course. The less details we dig up on a plane, the fewer skeletons we find in the cupboard. But that doesn`t effect the actual number of skeletons overall. They are there, even if we don`t know about it.

BTW, ever wondered why the 'pointed', ie. tall vertical stabiliser was introduced to the Spitfire..? Stabiliser fin to the p51d..? Tall tail to the 109?

These aircraft had more in common than not. Designers kept bumping into the same limits, no matter the country. Physics are universal.

The instruction that I referred to in my previous posting was specifically for the Me109G so yes I do believe that the problem existed in the 109G.

Of course any aircraft then or now that exceeds its design limits is in danger of structural failure, that is obvious.

The difference here is that the German authorities had to issue a reminder to all German units that started

Owing to continually recurring accidents caused by wing breakages in Me109 aircraft attention is drawn to the following

Then it lists various items including the item on wing tips. Now this is a document issued to units after that have been equipped and trained on the aircraft over and above the normal pilots notes.

The fact that the authorities had to issue such a reminder implies to me that the problem was greater on the 109 than other aircraft, as I have never heard of such a reminder being issued to other airforces or aircraft. After all, if the problem was the same on all aircraft and the Germans were being more communatitive than other nations, why didn't they issue similar reminders for all their 190's, 110's etc?

You will recall that JG26 in its list of pilots lost to accidents, treated wing failure as another type of accident, again something I have never heard of in any US or British record. Another indication that it was more common in German aircraft.

I would be the first to agree that this isn't definite proof but the circumstancial evidence builds up the more you look into it.

[Crumpp]

He was one hell of a fighter pilot but perhaps an even better instructor. I miss him still and it's been 28 years.

Yes he was and he is missed. Men of his caliber and generation are a precious dwindling resource.

Glider,

treated wing failure as another type of accident, again something I have never heard of in any US or British record.

How do you explain the USAAF documents?

How do you explain the RAF warnings?

Now this is a document issued to units after that have been equipped and trained on the aircraft over and above the normal pilots notes.

Just like the RAF and USAAF documents.

why didn't they issue similar reminders for all their 190's, 110's etc?

They did....

Another indication that it was more common in German aircraft.

This is an airplane issue not a cultural defect. The Germans were not nor are they incompetant as a race.

Glider, IMHO, comments like this are a slap in the face to every guy who fought in the skies over Europe. I am sure you did not think of it that way when you wrote it. The Luftwaffe was not some push over organization flying half-baked airplanes. Both Allied and Axis flew the best technology mankind had to offer. The Nazi's were defeated because good men went forth everyday and risked all of their tommorrows in a hard won fight.

All the best,

Crumpp