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Old 01-25-2012, 06:09 PM   #1
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Balsa coring

Just watched a movie about the construction process of the de Havilland Mosquito which was built in England, Canada, and Australia.* I have always known the plane was all-wood but did not know how it was actually constructed.

Turns out the fuselage was monocoque and constructed of a balsa core covered on both sides*with 3-ply plywood.* All this was shaped over forms with bands holding it down while the glue bonding it all together dried.* The glue*was referred to*in the movie as*"cold glue" and it was slathered on with big paint brushes.

So balsa coring as a concept has been around for awhile......


-- Edited by Marin on Wednesday 25th of January 2012 07:10:43 PM
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Old 01-25-2012, 07:28 PM   #2
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RE: Balsa coring

Great technique, as long as everybody understands balsa rots if it gets wet. I had a Cruisers that used that below the waterline. One shipyard installed a thru-hull without putting epoxy between the balsa and metal. Always worried me until I sold that boat.
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Old 01-26-2012, 05:40 AM   #3
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RE: Balsa coring

So balsa coring as a concept has been around for awhile......

But never on something built to last.

Balsa rots faster than last weeks tomatoes.
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Old 01-26-2012, 11:57 AM   #4
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RE: Balsa coring

Quote:
FF wrote:
So balsa coring as a concept has been around for awhile......

But never on something built to last.

Balsa rots faster than last weeks tomatoes.
*This is true.* The life-expectancy of a Mosquito in a combat theatre was measured in weeks, not years.

When I hired into Boeing I met an engineer who had been an FW-190 pilot in the Luftwaffe during the war.* He thought it was hillarious that people spend tons of money to restore and fly FW-190s and Bf-109s, planes which he said were originally designed and built for an operational lifetime of 25 hours.
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Old 01-26-2012, 12:20 PM   #5
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RE: Balsa coring

Wow!! 25 hours a disposable fighter.

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Old 01-26-2012, 01:12 PM   #6
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RE: Balsa coring

Quote:
skipperdude wrote:
Wow!! 25 hours a disposable fighter.

SD
I wonder if that was based on the plane or the life expectancy of the pilot.*

I bet it was a lot less than 25 hours after the P-51's were fully deployed.
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Old 01-26-2012, 01:15 PM   #7
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Balsa coring

Quote:
Marin wrote:FF wrote:
So balsa coring as a concept has been around for awhile......

But never on something built to last.

Balsa rots faster than last weeks tomatoes.
*He thought it was hillarious that people spend tons of money to restore and fly FW-190s and Bf-109s, planes which he said were originally designed and built for an operational lifetime of 25 hours.

*Maybe they thought the P-51 and*P - 38*and their drivers*were just that much better and were going to shoot them down anyway.


-- Edited by JD on Thursday 26th of January 2012 02:52:56 PM
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Old 01-26-2012, 01:39 PM   #8
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Balsa coring

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JD wrote:
*Maybe they thought the P-51 and and P - 38*snf their drivers*were just that much better and were going to shoot them down anyway.

The Bf 109 and FW-190 were designed and put into production-- and in the case of the Bf-109 fought in a war (Spain---) long before the P-51 made an appearance.* And the P-51 as designed was a very mediocre airplane.* In fact its performance was so underwhelming that the program was on the verge of being cancelled.* However the US government sent some to the RAF in England (it was the British that gave the plane the name Mustang, by the way), and the British, after seeing what a crummy airplane it was compared to the Spitfire, were about to dowgrade them to training aircraft when someone got the idea of putting a Rolls Royce Merlin engine in one in place of the factory-installed Allison.

The rest, as they say, is history.* The Merlin totally transformed the P-51, Packard was awarded a license to build the Rolls Royce Merlin engine in the US, the Air Corps continued the P-51 program, and the plane went on to become one of the best fighters of the war.

The ex-FW-190 pilot told us that the Bf-109 and FW-190 were designed with a short life expectancy because the experience of WWI had shown that figher aircraft did not survive very long.* Pilot error was as much a factor if not more so as being shot down.* So the manufactures focused their design efforts on performance and low cost and speed of manufacture.* Longevity, according to him,*was not a priority.

*


-- Edited by Marin on Thursday 26th of January 2012 06:24:20 PM
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Old 01-28-2012, 03:34 AM   #9
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RE: Balsa coring

Quote:
Marin wrote:JD wrote:**And the P-51 as designed was a very mediocre airplane.* In fact its performance was so underwhelming that the program was on the verge of being cancelled.* However the US government sent some to the RAF in England (it was the British that gave the plane the name Mustang, by the way), and the British, after seeing what a crummy airplane it was compared to the Spitfire, were about to dowgrade them to training aircraft when someone got the idea of putting a Rolls Royce Merlin engine in one in place of the factory-installed Allison.
The rest, as they say, is history.* The Merlin totally transformed the P-51, Packard was awarded a license to build the Rolls Royce Merlin engine in the US, the Air Corps continued the P-51 program, and the plane went on to become one of the best fighters



-- Edited by Marin on Thursday 26th of January 2012 06:24:20 PM

*Hmmmmmmmm interesting rewrite of history
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Old 01-31-2012, 01:32 PM   #10
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Balsa coring

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rednev wrote:06:24:20 PM
*Hmmmmmmmm interesting rewrite of history

*From that comment I can only assume you have never read the correct history of the P-51.* The information I wrote I got from North American's* archives which we (Boeing) now own.* Here's some more of it.

The intital P-51 was an impressive plane aerodynamically but its Allison engine did not give it good performance above 15,000 feet, just as they did not give any airplane equipped with them good performance at altitude-- P-40, P-39, etc.* The P-38 had two of them and they were supercharged, which is why that airplane had much better performance than the planes with just one.

Not until the P-51 was fitted with a Rolls Royce Merlin did the it's potential become apparent.

One thing most people don't know is that the P-51 originated not as a US airplane but as the result of* a request from the British to the US for a fighter that could be developed for them in 120 days . At the time they needed fighters to augment their own planes but no American plane in production met the British requirement.* The Curtiss P-40 came the closest but P-40 production was running at capacity already.

It was determined that it would be faster to create a new, better plane to meet the British request using the same Allison engine as the P-40 than it would to set up a production line for the P-40 itself.* North American, which at the time was just building T-6 trainers, was given the task.

The project to create a plane for the British was called the NA-73X and the prototype was completed in late 1940.* The first 300 planes were ordered by the British Ministry of Air Production.

The plane that eventually became the P-51 was initially called the Apache.* The British called the planes they received the Mustang I.* It was far superior to the P-40, but like the P-40, it's performance at altitude was pretty sluggish.* The US Air Corps was initially underwhelmed by the Mustang and largley ignored it, even to the point of it being suggested it might make a good advanced trainer.

In 1942 British test pilot Ronald Harker flew a Mustang and while he was extremely impressed with the plane at lower altitudes he, too, noted that it "died" above 15,000 feet.* He suggested it would do far better with a Rolls Royce Merlin in it. * The pairing of the Merlin with the Mustang airframe totally transformed the plane and North American began fitting them with Packard's license-built Rolls Royce Merlin.* At this point the US Army Air Corps began to take notice and the 1943 they introduced the P-51 into combat roles on a large scale.

It is considered the best fighter of WWII but it was not the best in every aspect.* The Spitfire was considerably more maneuverable than the P-51 and was considered the superior dogfighting airplane.* However the Mustang--- due largely to its fuselage design which gave it a very large fuel capacity--- had the longer range.* As one fighter pilot who flew both put it, he would prefer to fight a German fighter in a Spitfire unless it was over Berlin, in which case he would want the Mustange because it could get him home after the fight.


-- Edited by Marin on Tuesday 31st of January 2012 02:44:57 PM
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Old 02-01-2012, 02:02 AM   #11
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RE: Balsa coring

Quote:
Marin wrote:rednev wrote:06:24:20 PM
*Hmmmmmmmm interesting rewrite of history

*From that comment I can only assume you have never read the correct history of the P-51.* The information I wrote I got from North American's* archives which we (Boeing) now own.* Here's some more of it.

archive documents ( contracts ect ) or pr dept spin ?

The intital P-51 was an impressive plane aerodynamically but its Allison engine did not give it good performance above 15,000 feet, just as they did not give any airplane equipped with them good performance at altitude-- P-40, P-39, etc.* The P-38 had two of them and they were supercharged, which is why that airplane had much better performance than the planes with just one.**** Wright fields evaluatin sums it up below 22,000ft the p51has the best all round fighting qualities of any fighter

Not until the P-51 was fitted with a Rolls Royce Merlin did the it's potential become apparent.***** *so all those expert observers (including eddie rickenbacker )sending reports back to gen arnold suggesting that the p51 be fitted with the merlin didnt see its potential ?

One thing most people don't know is that the P-51 originated not as a US airplane but as the result of* a request from the British to the US for a fighter that could be developed for them in 120 days . At the time they needed fighters to augment their own planes but no American plane in production met the British requirement.* The Curtiss P-40 came the closest but P-40 production was running at capacity already.***

*But your first post said the stangs performance was so underwhelming the us sent some to england

It was determined that it would be faster to create a new, better plane to meet the British request using the same Allison engine as the P-40 than it would to set up a production line for the P-40 itself.* North American, which at the time was just building T-6 trainers, was given the task.

How about the british purchasing commision approache nort american to build the p40 under licence and nrth american counted with a proposal to build a better fighter in a shorter time frame than it would need to tool up for p40 production.dutch kindlerberger had toured british and german facilities in 1938 and had constant feed back from expert observers in europe hence his quote you cant pull a rabbit out of a hat unless you carefully put a rabbit in the hat beforehand .

The project to create a plane for the British was called the NA-73X and the prototype was completed in late 1940.*** na-73x first flight as nx-19998 october 26th 1940

*

*

*The first 300 planes were ordered by the British Ministry of Air Productie plane that eventually became the P-51 was initially called the Apache.* The British called the planes they received the Mustang I.* It was far superior to the P-40, but like the P-40, it's performance at altitude was pretty sluggish.* The US Air Corps was initially underwhelmed by the Mustang and largley ignored it, even to the point of it being suggested it might make a good advanced trainer.

The us air corps was going o cancel a british project ? Reading between the lines the air corps seemed to dimiss the mustang because it was built to a british specifaction for the british not really a true american aircraft ( funny because history judged it a n american icon )

*

In 1942 British test pilot Ronald Harker flew a Mustang and while he was extremely impressed with the plane at lower altitudes he, too, noted that it "died" above 15,000 feet.* He suggested it would do far better with a Rolls Royce Merlin in it. * The pairing of the Merlin with the Mustang airframe totally transformed the plane and North American began fitting them with Packard's license-built Rolls Royce Merlin.* At this point the US Army Air Corps began to take notice and the 1943 they introduced the P-51 into combat roles on a large scale.******** Fitting a different engine dosnt turn a sows ear into a silk purse it did however turn a very good aircraft into a great aircraft

It is considered the best fighter of WWII but it was not the best in every aspect.* The Spitfire was considerably more maneuverable than the P-51 and was considered the superior dogfighting airplane.* However the Mustang--- due largely to its fuselage design which gave it a very large fuel capacity--- had the longer range.* As one fighter pilot who flew both put it, he would prefer to fight a German fighter in a Spitfire unless it was over Berlin, in which case he would want the Mustange because it could get him home after the fight.

The term fighter is a bit misleading . the spit was a point defence air superiorty fighter the stang an escort fighter .bit like coastal cruiser long range passagemaker different set of compromises but look to the untrained eye the same.

If you look at the grumman archives you will be told (by the pr dept ) that the hellcat was designed from combat experience gain with the wildcat .but the hellcat was off the board before the wildcat saw combat.* just saying ya have to dig a little deeper than company fluff pieces
-- Edited by Marin on Tuesday 31st of January 2012 02:44:57 PM

*
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Old 02-01-2012, 11:29 AM   #12
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RE: Balsa coring

Quote:
rednev wrote:-- Edited by Marin on Tuesday 31st of January 2012 02:44:57 PMjust saying ya have to dig a little deeper than company fluff pieces
*

*True.* And had I gotten my information about the P-51 from "company fluff pieces" you would be correct.* However, the information I have gotten in the course of my work-- not only about the P-51 but the B-29, B-17, and B-52 all for video documentaries I wrote and produced about the planes for my employer and the Museum of Flight--- came from reams and reams of archival material including notes from production concept meetings, design studies, reports and direct interviews (in the case of people who were still alive) from the aero engineers who were designing the planes, test pilots who flew them, combat pilots and aircrews who flew them, and so on.

This was a long time before the popularity of the internet and Wikipedia, which is useful but often wrong.* You can probably find most of the information on the internet now, but that is not as realiable a source as reading the actual archival material and talking to the actual people involved.

As to a couple of your points in your post,the US undertook the P-51 project as way of supporting a British request.* It was not a "British project" and the Air Corps had complete control of the project and its fate.

And your statement that a different engine cannot completely transform a plane, you are dead wrong on that one, and not just with regard to the Mustang.* Even the lowly deHavilland DHC-3 Otter was saved from oblivion by an engine change.* Twice.
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Old 02-01-2012, 01:43 PM   #13
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RE: Balsa coring

Quote:
Marin wrote:Even the lowly deHavilland DHC-3 Otter was saved from oblivion by an engine change.* Twice.
* * * ** True!* I've flown out to a SE Alaska fish camp in one several times.
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