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Blutarski2004
05-19-2004, 11:55 AM
I ran across a website in my recent travels which gives an interesting perspective on the issue of P51 wing-shedding. The author states that cause of this wing shedding was tracked down to ammunition bay doors springing open under high G stresses and was fixed, presumably sometime in the second half of 1944.

Can anyone corroborate this?

As a pure bit of speculation, I wonder if the gun jamming of the P51B/C might have been related to this problem. These gun jams were also observed to occur under heavy G loads. I could visualize a gun jam causing the cartridge belt feeding the jammed gun to suddenly "bunch up" (due to the intertia of its feed rate) under the ammunition bay door and perhaps pop it open.

Interesting issue.

BLUTARSKI

Blutarski2004
05-19-2004, 11:55 AM
I ran across a website in my recent travels which gives an interesting perspective on the issue of P51 wing-shedding. The author states that cause of this wing shedding was tracked down to ammunition bay doors springing open under high G stresses and was fixed, presumably sometime in the second half of 1944.

Can anyone corroborate this?

As a pure bit of speculation, I wonder if the gun jamming of the P51B/C might have been related to this problem. These gun jams were also observed to occur under heavy G loads. I could visualize a gun jam causing the cartridge belt feeding the jammed gun to suddenly "bunch up" (due to the intertia of its feed rate) under the ammunition bay door and perhaps pop it open.

Interesting issue.

BLUTARSKI

Kurfurst__
05-19-2004, 12:03 PM
"The Mustang had been dogged by instances of structural failure, particularly since the marriage to the Merlin. Flight restrictions on dives and other manoeuvres were imposed, but in the course of combat, these sometimes had to be ignored. The puzzling thing about Mustang airframe failure was that it could not be pinpointed to any one area and was sometimes encountered in brand-new aircraft that had not undergone any known flight strain. Engines tore loose from fuselages, wings were shed, and empennages crumpled and while most of these incidents happened during a sharp manoevre it was a fact that other Mustangs would engage in the same manoevre time and again without any sign of failure. Some components were strengthened - notably the fin and undercarriage door locks (which had a nasty habit of breaking open) - but a few cases of airframe failure were regularly reported to the end of hostilities and beyond."

- Roger Freeman, "Mustang at War".


"'I witnessed this [Mustang wing] loss on two occasions. One wing was lost directly over the airfield at Madna, Italy in the fall of 1944. The airplane and pilot went straight into the ground not far from the control tower. One other loss occurred there during an afternoon 'rat race.' Coincidentally we were discussing this wing loss with Johnny Typer, the civilian representative from NAA at the time. He was adamant that no-one could pull the wings off a P-51. No sooner had he made that remark than I heard behind me the dull thumps of two wings separating. He asked 'What's that?' and I answered that it had happened again. He asked how I knew, to which I replied, 'Once you've heard that sound, you'll never forget it." We watched as the litter and tumbling wings fell slowly to the ground, long after the fuselage and pilot had crashed - an unforgettable sight and feeling."

- Lt. William G. Coloney, 52nd FG,

http://www.x-plane.org/users/isegrim/fat-furred%20tigerB.jpg

"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".
- Lt. Gen. George S. Patton, Jr. Febuary 1945.

"One day a Tiger Royal got within 150 yards of my tanks and knocked me out. Five of our tanks opened up on him at ranges of 200 to 600 yards and got 5 or 6 hits on the front of the Tiger. They all just glanced off and the Tiger backed off and got away. If we had a tank like that Tiger, we would all be home today."
- Sgt. Clyde D. Brunson, US Army, Tank Commander, February 1945

Blutarski2004
05-19-2004, 02:38 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Kurfurst__:
"The Mustang had been dogged by instances of structural failure, particularly since the marriage to the Merlin. Flight restrictions on dives and other manoeuvres were imposed, but in the course of combat, these sometimes had to be ignored. The puzzling thing about Mustang airframe failure was that it could not be pinpointed to any one area and was sometimes encountered in brand-new aircraft that had not undergone any known flight strain. Engines tore loose from fuselages, wings were shed, and empennages crumpled and while most of these incidents happened during a sharp manoevre it was a fact that other Mustangs would engage in the same manoevre time and again without any sign of failure. Some components were strengthened - notably the fin and undercarriage door locks (which had a nasty habit of breaking open) - but a few cases of airframe failure were regularly reported to the end of hostilities and beyond."

- Roger Freeman, "Mustang at War".


"'I witnessed this [Mustang wing] loss on two occasions. One wing was lost directly over the airfield at Madna, Italy in the fall of 1944. The airplane and pilot went straight into the ground not far from the control tower. One other loss occurred there during an afternoon 'rat race.' Coincidentally we were discussing this wing loss with Johnny Typer, the civilian representative from NAA at the time. He was adamant that no-one could pull the wings off a P-51. No sooner had he made that remark than I heard behind me the dull thumps of two wings separating. He asked 'What's that?' and I answered that it had happened again. He asked how I knew, to which I replied, 'Once you've heard that sound, you'll never forget it." We watched as the litter and tumbling wings fell slowly to the ground, long after the fuselage and pilot had crashed - an unforgettable sight and feeling."

- Lt. William G. Coloney, 52nd FG,

<HR></BLOCKQUOTE>


Hence my question as to whether anyone can corroborate this claim. I have never seen it mentioned before and the author provides no citation.

BLUTARSKI

RAF74_Buzzsaw
05-19-2004, 03:11 PM
Salute

Isegrim's information is false, as usual.

The P-51 had problems with losing wings ONLY when it had the 85 gallon tank behind the seat filled to maximum. This caused the center of gravity to shift and put stresses on the wings.

When the tank was empty, there were no problems.

The USAAF issued a cautionary notice to all pilots instructing them to burn off fuel from the behind the seat tank before any other fuel.

By the way, the 109 had many problems with wing loss and structure failure recorded. They were particularly prone to losing wings during extended dives.

PzKpfw
05-19-2004, 03:24 PM
When they added the 85 gallon fuselage tank, & when it was full, it shifted COG which made the P-51 longitudinally unstable.

Which made high speed pull outs dangerous, as a stick reversal occured , which if not opposed by the pilot, would put the P-51 into an 'accelerated condition' and the wings would fail at the inboard end of the gun bays.

Also it was reported that G-suits were allowing pilots to exceed the airframe limits, Ie, P-51s returned with stress damage & some even repoportedly broke up during high G manouvers, in which the loss was blamed on the pilot.

Regards, John Waters

---------
Notice: Spelling mistakes left in for people who need to correct others to make their life fulfilled.

----
The one that gets you is the one that you'll never see.
-----

----

"After 44 we called the new models the 'bumps', because every new model had another bump or hump on the fuselage, which naturally was particularly bad for the flight characteristics of the aircraft."

Walter Krupinski: on the Bf 109...
----

-----
"The damn Jerries have stuck their heads in the meatgrinder, and I've got hold of the handle."

Lt.Gen. George S. Patton, Jr. December 26, 1944.

------
"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. Febuary 1945.

------
For Americans war is almost all of the time a nuisance, and military skill is a luxury like Mah-Jongg. But when the issue is brought home to them, war becomes as important, for the necessary period, as business or sport. And it is hard to decide which is likely to be the more ominous for the Axis--an American decision that this is sport, or that it is business."
--D. W. Brogan, The American Character

WWMaxGunz
05-19-2004, 03:27 PM
It would be more productive to ask what percent or how many total but then that can be claimed to be obscured by action. It happened. It happened to a number of plane types. Other failures happened. Give the right person as few as 10 examples and it's the start of Yet Another Flame War.

All ashore that's going ashore! This thread headed for all points here to infinity! Ise and Buzz have started up and Be Sure they have the "data" and "facts" either bookmarked or memorized.

(Leaping from thread to nowhere...)

Neal

RAF74_Buzzsaw
05-19-2004, 08:38 PM
Salute

What we have here is another thinly veiled attempt by the Luftwhiners to sabotage an allied aircraft.

I respond to these with the facts.

Issy/Kurfurst knows the facts, this issue has been discussed in great detail in earlier threads. But he never tires of presenting the same old disinformation time and time again in the hopes that Oleg will be influenced.

It's time that people who should know better start posting with some integrity.

Don't class me with Isegrim/Kurfurst. I have posted many times in support of improvements in the Focke-Wulf 190 in the past, whether it was in regards to the cockpit view or the high speed handling, or the dive acceleration. Do a search.

Blutarski2004
05-20-2004, 09:20 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RAF74BuzzsawXO:
Salute

What we have here is another thinly veiled attempt by the Luftwhiners to sabotage an allied aircraft.

I respond to these with the facts.

Issy/Kurfurst knows the facts, this issue has been discussed in great detail in earlier threads. But he never tires of presenting the same old disinformation time and time again in the hopes that Oleg will be influenced.

It's time that people who should know better start posting with some integrity.

Don't class me with Isegrim/Kurfurst. I have posted many times in support of improvements in the Focke-Wulf 190 in the past, whether it was in regards to the cockpit view or the high speed handling, or the dive acceleration. Do a search.<HR></BLOCKQUOTE>


Buzz,

Isegrim/Kufurst can always be relied upon to deliver his contributions, such as they are, to discussions of this sort. I have no control over that and did not post this topic with the intention of provoking a flame war.

Having missed the earlier thread discussion to which you refer, I'm interested in your take on the P51 wing-shedding phenomenon. Was the explicit cause ever actually identified? How was it dealt with? Was the slightly re-designed wing of the P51 D model perhaps a part of the solution?

BLUTARSKI

Kurfurst__
05-20-2004, 09:35 AM
Lovely thread. Most interesting things of all, you guy require absolutely no input from me to start flaming.

One just wonders, how can two quotes w/o any comments have such an effect on _normal_ people.. ? http://ubbxforums.ubi.com/infopop/emoticons/icon_cool.gif

http://www.x-plane.org/users/isegrim/fat-furred%20tigerB.jpg

"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".
- Lt. Gen. George S. Patton, Jr. Febuary 1945.

"One day a Tiger Royal got within 150 yards of my tanks and knocked me out. Five of our tanks opened up on him at ranges of 200 to 600 yards and got 5 or 6 hits on the front of the Tiger. They all just glanced off and the Tiger backed off and got away. If we had a tank like that Tiger, we would all be home today."
- Sgt. Clyde D. Brunson, US Army, Tank Commander, February 1945

Blutarski2004
05-20-2004, 09:49 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Kurfurst__:
Lovely thread. Most interesting things of all, you guy require absolutely no input from me to start flaming.

One just wonders, how can two quotes w/o any comments have such an effect on _normal_ people.. ? http://ubbxforums.ubi.com/infopop/emoticons/icon_cool.gif
<HR></BLOCKQUOTE>


Kurfurst,

Thank you for your contribution. Besides the two quotations which you provided, do you have any thoughts to contribute on the actual topic under discussion?

BLUTARSKI

Kurfurst__
05-20-2004, 11:05 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blutarski2004:
Kurfurst,

Thank you for your contribution. Besides the two quotations which you provided, do you have any thoughts to contribute on the actual topic under discussion?

BLUTARSKI

<HR></BLOCKQUOTE>

Yep. Appearantly from the quotes, despite it was claimed a fix was found and put forward, the wing breakages continued to occur even as late as 1945. I would say they did not found the problem itself, altough they searched quite hard for it, ie. the tailplane was in focus for some time, then the ammo bay doors, and the undercarriage locks as well. Fixes were put forward which either worked as they thinked or not, however, wings kept shredding on occasion. It could be as well that the design had no problems, but the production quality was poorer than expected.

As pointed out by others, vibration during dive and longitudal instability were major causes for stress, which becamome aggrevated under compressibility. The redesign with the P-51D which set compressibity to happen earlier on may have negated the fixes put forward.


Here are a few more quotes in this regard :

"A Mustang III Ser No KH 505 was allocated to the RAE for high speed research, and this showed up some unpleasant compressibility effects, and indeed the aircraft was eventually lost in failing to recover fro a high mach number dive, killing the Canadian pilot, S/Ldr. E.B.Gale.
In such dives compressibility effects set in at M=0.71 with a slight vibration of the aircraft and buffeting of the controls, accompanied by a slight nose down pitching moment. These symptoms increased in intensity up to M=0.75 which was the limit imposed for service use. Above M=0.75 a porposing motion started and increased in intensity together with the other effects up to M=0.8, when nose down pitch became so strong that it required a two handed pull force for recovery."

By Eric Brow


Change of onset of compressibilty with D version aerodynamic changes


American pilot Robert C.Curtis remmembers :

"My flight chased 12 109s south of Vienna. They climbed and we followed, unable to close on them. At 38,000 feet I fired a long burst at one of them from at least a 1000 yards, and saw some strikes. It rolled over and dived and I followed but soon reached compressibility with severe buffeting of the tail and loss of elevator control. I slowed my plane and regained control, but the 109 got away.
On two other occasions ME 109s got away from me because the P 51d could not stay with them in a high-speed dive. At 525-550 mph the plane would start to porpoise uncontrollably and had to be slowed to regain control. The P 51 was redlined at 505 mph, meaning that this speed should not be exceeded. But when chasing 109s or 190s in a dive from 25-26,000 it often was exceeded, if you wanted to keep up with those enemy planes. The P 51b, and c, could stay with those planes in a dive. The P 51d had a thicker wing and a bubble canopy which changed the airflow and brought on compressibility at lower speeds"

http://www.x-plane.org/users/isegrim/fat-furred%20tigerB.jpg

"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".
- Lt. Gen. George S. Patton, Jr. Febuary 1945.

"One day a Tiger Royal got within 150 yards of my tanks and knocked me out. Five of our tanks opened up on him at ranges of 200 to 600 yards and got 5 or 6 hits on the front of the Tiger. They all just glanced off and the Tiger backed off and got away. If we had a tank like that Tiger, we would all be home today."
- Sgt. Clyde D. Brunson, US Army, Tank Commander, February 1945

p1ngu666
05-20-2004, 11:58 AM
good reason to fly a biplane really http://ubbxforums.ubi.com/images/smiley/16x16_smiley-tongue.gif http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif
and losing the ammo panels etc would cause strange air pressure and vaccums on the wing:/
another reason could be faults in the metal, in a program about F1 i saw some strange test for compoents, under uv light with die a faultline appeared. (plus magnets i think + Other stuff)
invisible to the nakid eye.

http://www.pingu666.modded.me.uk/mysig3.jpg
&lt;123_GWood_JG123&gt; NO SPAM!

LeadSpitter_
05-20-2004, 12:02 PM
I never read anything about that, I know earlier p51s had a problem shedding its elevators and rudder in high speed dives but it was corrected.

Nothing more then the many occasions LAs and yak wings just broke off in flight from stress,

http://img14.photobucket.com/albums/v43/leadspitter/LSIG1.gif

PzKpfw
05-20-2004, 12:08 PM
Walter Konantz: 55th FG P-51D September 1944*:

I looked up just in time to see fifty or sixty ME-109s streaming through our formation in a forty-five degree dive with their guns fireing. Fortunately, none had picked me as a target but one crossed right in front of me fireing at a Mustang below and to my left.

These were te first enemy airplanes I had ever laid eyes on and buck fever and instinct caused me to roll over in a dive after the ME-109. He saw me comeing and steepened his dive to the vertical.

We both now headed straight down from 24,000 feet on a wide open power dive. Both airplanes were very skittish from extremely high speed and since I was not strapped in, the slightest movement of the stick caused me to leave the seat and hit the canopy above. I was in a neutral-G situation, just floating inside the cockpit.

We passed through a layer of slight turbulence and I felt like a basketball being dribbled down the court. The ME-109 was haveing as much trouble as me, his plane was bucking and skidding as both of us were nearing compressibility, the limiting speed at which the plane no longer responds to the controls.

At 10,000 feet, I initiated a steady four-G pullout and the ME-109 started to pull out about the same time. But before he had raised his nose more then thirty degrees, his right wing ripped off through the wheel well and he spun into the ground in a matter of seconds.

He had no time to get out and was still aboard when the 109 impacted and exploded in a wooded area. Just before I started my pull-out I glanced at the airspeed indicator and saw the needle on 600 miles an hour, ninety-five per hour over the red-line speed of 505.

*See: Astor Gerald. The Mighty Eighth p.365

Regards, Jolhn Waters

---------
Notice: Spelling mistakes left in for people who need to correct others to make their life fulfilled.

----
The one that gets you is the one that you'll never see.
-----

----

"After 44 we called the new models the 'bumps', because every new model had another bump or hump on the fuselage, which naturally was particularly bad for the flight characteristics of the aircraft."

Walter Krupinski: on the Bf 109...
----

-----
"The damn Jerries have stuck their heads in the meatgrinder, and I've got hold of the handle."

Lt.Gen. George S. Patton, Jr. December 26, 1944.

------
"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. Febuary 1945.

------
For Americans war is almost all of the time a nuisance, and military skill is a luxury like Mah-Jongg. But when the issue is brought home to them, war becomes as important, for the necessary period, as business or sport. And it is hard to decide which is likely to be the more ominous for the Axis--an American decision that this is sport, or that it is business."
--D. W. Brogan, The American Character

[This message was edited by PzKpfw on Thu May 20 2004 at 03:45 PM.]

Blutarski2004
05-20-2004, 12:14 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Kurfurst__:
Appearantly from the quotes, despite it was claimed a fix was found and put forward, the wing breakages continued to occur even as late as 1945. I would say they did not found the problem itself, altough they searched quite hard for it, ie. the tailplane was in focus for some time, then the ammo bay doors, and the undercarriage locks as well. Fixes were put forward which either worked as they thinked or not, however, wings kept shredding on occasion. It could be as well that the design had no problems, but the production quality was poorer than expected.

As pointed out by others, vibration during dive and longitudal instability were major causes for stress, which becamome aggrevated under compressibility. The redesign with the P-51D which set compressibity to happen earlier on may have negated the fixes put forward.
<HR></BLOCKQUOTE>


It is indeed a puzzler. Some sources view this as being induced by high G conditions, while others see it as a result of excessive dive speeds. Could it be related to dive pull out attempts? I suspect that popping ammunition bay doors and gear covers were more likely symptoms of the problem than causes. I'm surprised that no related documents have been found on the NACA website.

Another X factor is the lack of consistency in the occurence of the phenomenon. Most of the time, it appears there was no problem; then suddenly off comes a wing. This hints toward the possibility of intermittent manufacturing defects OR undetected prior stress damage to the wings. It would be interesting to know the frequency of this sort of accident. It seems that the problem was not perceived as severe enough at the time to either ground the plane (unlike the engine mount problem) or unduly restrict its flight envelope. Yet, at least based upon one of the P51 pilot quotations above, it appears that wing shedding by the P51 was not considered by them to be an altogther rare event.

BLUTARSKI

RAF74_Buzzsaw
05-20-2004, 12:20 PM
Salute

All of your suggestions that the P-51 was more prone to losing wings are entirely speculative, and you have provided ZERO documentation, ie. USAAF documents indicating that this was a problem.

Please provlde the documentation or drop it.

As mentioned there were USAAF memos issued re. the center of gravity shift after introduction of the 85 gallong fuel tank along with cautions to pilots requiring them to avoid combat maneuvers while it was full, but there are ZERO reports regarding problems when this tank was less than 1/2 full.

Blutarski2004
05-20-2004, 01:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RAF74BuzzsawXO:
Salute

All of your suggestions that the P-51 was more prone to losing wings are entirely speculative, and you have provided ZERO documentation, ie. USAAF documents indicating that this was a problem.

Please provlde the documentation or drop it.

As mentioned there were USAAF memos issued re. the center of gravity shift after introduction of the 85 gallong fuel tank along with cautions to pilots requiring them to avoid combat maneuvers while it was full, but there are ZERO reports regarding problems when this tank was less than 1/2 full.<HR></BLOCKQUOTE>


Buzz,

The effect upon handling of that added 85gal tank is another possible explanation. As a wartime measure, any change in c/g caused by the addition of this tank would certainly have introduced stresses upon the airframe which were never anticipated in the original design work. These stresses would be amplified by orders of magnitude under high G conditions. It could also explain the intermittent nature of these wing failures - most of the time tank contents were in order and no ill effects ensued; at other times a too full tank worked its mischief. In the heat of battle, it would be easy to forget or ignore the problem.

Do any of the USAAF docs which you have seen make a conection between wing failure problems and auxiliary tank fill levels?

BLUTARSKI

PzKpfw
05-20-2004, 02:31 PM
Again, the Mustang's 85 gal fuselage tank when full was the main culprit in the wing failure problems. When the tank was below half full their were no longitudinally unstability problems reported, in high g pullouts etc.

Maximum permissible dive speed for a P-51D was *505mph IAS below 9000ft, & 300mph IAS (539mph TAS) @ 35000ft. Maximum allowed engine overspeed in a dive was 3300 RPM (or 10% over normal maximum).

The P-51D was put thru extensive dive tests @ *Wright field in 1944 with 3 test pilots. The P-51s were equipped with a MACH meter to evaluate the effects of compressibility:, buffeting, vibration, contrl force changes etc. .

Tests were conducted from 35000ft, Initial dives, showed the onset of problems @ just under Mach.75, additional tests pushed the P-51 to Mach.77, .79, And finaly to Mach.83 (605mph TAS).

As mach increased compressibility effects became more violent, but the P-51 was still controlable, and able to pull out etc. @ Mach.83 the effects were so strong that tests were ended. The test P-51 @ Mach .83 pulled out but suffered extensive structural damage and was written off, after landing.

Not one instance of wing shedding in these tests.

*See: Dean Francis H. America's Hundred-Thousand pp.343 - 344.

Also if these wing shredding incidents were as common as some would have it with the P-51, then why; was it not present, on the the A-36? which was an P-51 used as a dive bomber, and not one incedent; of longitudinally unstability or 'wing shredding' was reported, Ie, an single A-36 of the 27th FBG flew 150 missions with not one incident.


We should also not dismiss offhand the effects G-suits might have had on the few later incidents either, as their were reports, after G-suits became common of P-51s RTB with heavy airframe stress damage & even breaking up in flight, during hard manouvering.

G-suits were believed to be the primary cause of of isolated P-51 airframe losses, as pilots were pushing P-51s beyond their stress limits in high G manouvers that could not have possible before the arrival of G-suits.


Regards, John Waters

---------
Notice: Spelling mistakes left in for people who need to correct others to make their life fulfilled.

----
The one that gets you is the one that you'll never see.
-----

----

"After 44 we called the new models the 'bumps', because every new model had another bump or hump on the fuselage, which naturally was particularly bad for the flight characteristics of the aircraft."

Walter Krupinski: on the Bf 109...
----

-----
"The damn Jerries have stuck their heads in the meatgrinder, and I've got hold of the handle."

Lt.Gen. George S. Patton, Jr. December 26, 1944.

------
"We've got the finest tanks in the world. We just love to see the German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. Febuary 1945.

------
For Americans war is almost all of the time a nuisance, and military skill is a luxury like Mah-Jongg. But when the issue is brought home to them, war becomes as important, for the necessary period, as business or sport. And it is hard to decide which is likely to be the more ominous for the Axis--an American decision that this is sport, or that it is business."
--D. W. Brogan, The American Character

[This message was edited by PzKpfw on Thu May 20 2004 at 04:30 PM.]

p1ngu666
05-20-2004, 04:23 PM
they had issues with asymetric dive brakes
iirec they wired em shut and lowered dive angle
id go for hidden defect, that would explain the random nature of them

http://www.pingu666.modded.me.uk/mysig3.jpg
&lt;123_GWood_JG123&gt; NO SPAM!