In Regard to the Ki-84...

[Shuckins]

A couple of years ago I briefly flirted with Warbirds.  On a number of occassions while flying the Frank, I took it into a high-speed dive, descending several thousand feet, and then attempted a high-g pullout.  At speed and gee-levels that caused little distress in American fighters, the Frank would shed its wings.

Some years back, I read an article in Wings or some other aviation magazine by a former WWII F4U pilot who stated that one of the standard escape tactics for Corsair pilots who were bounced by late-war Japanese fighters such as the Frank, was to go into a high-speed dive and then attempt a high-g pullout.  He stated further that the Japanese pilots would not follow for long in a sustained dive because they would shed their wings when trying to pull out.  

My question is, was the Frank modelled in Warbirds to simulate this, or was there some other reason that this occurred?  While the Frank was sturdier than the Zero or Oscar, it was still more lightly constructed than American fighters.  Unloaded weight was less than 5500 pounds, if memory serves, and when fully loaded, the Frank weighed around 7400 pounds.

Anyone have any insights to offer?

Regards, Shuckins

[Karnak]

I would expect that it probably had to do with poor quality control.

That is about the same weight as a Spitfire Mk IX, and the Spit certainly had no issues with shedding wings.

Also on the A6M, it wasn't a main spar failure that would hapen, it was the skin coming off.  That is why the thicker skin of the A6M5 allows for higher diving speeds.

Another point is that the P-51D had a wing shedding problem as well, and this is modeled in AH.

I would expect that you would have to watch your pull up Gs in the Ki.84 in AH the same way you must do that in the P-51D.

[Soulyss]

bit off topic, but what the hell

Was the P-51 wing shredding issue a matter of structural strength or was it related to the aft COG when the aux fuel tank was too full?

I know that with a full rear tank and pulling out of a dive and the stick reversal forces would cause the plane to try and swap ends and rip the wings off.  Was wing shredding still a problem when the center of gravity had moved forward?

[Karnak]

I seem to recall that the P-51's problem was a manufacturing error.  Once they found it they fixed it.

[BenDover]

What is this Warbird you speak of?

[Shuckins]

The problem of P-51s shedding their wings was eventually attributed to a tendency of the landing gear doors to extend from the wheel wells during high-speed dives.  They only extended by a minute amount, but the airflow around the wing under such conditions was so critical that this small disruption introduced twisting forces that ripped the wings from the fighter.

Regards, Shuckins

[Bullethead]

Karnak said

I would expect that it probably had to do with poor quality control.  That is about the same weight as a Spitfire Mk IX, and the Spit certainly had no issues with shedding wings.

You can rip the wings off a spit in AH if you try hard enough .  It's just not something you normally encounter in the MA because most fights are at 5k AGL or less, due to the emphasis on airfield capturing.  At such low alts, you don't often have a chance to get going fast enough to rip the wings.  

I figure the same would be true for the Ki84--its wings would rip at some point, but you'd hardly ever enter that regime in the normal course of play.  It was like this in AW and WB as well.  Basically, the bulk of MA fights took place at low enough alts where the Ki84 could exploit its speed advantage over almost all other planes without having to worry about going too fast.

[frank3]

So, Frank is a good plane? must be cause of the name

[Frost]

I remember in AWIII that the Frank, Zero and N1K2 would all rip their wings sooner than most other planes.  I was surprised when I started flying here that the N1K2 kept it's wings like it does.  Of course I have no idea which FM is more accurate, but it would be nice to have it modeled as correctly as possible.  Would be nice to use a nice steep dive again to rid myself of a pesky N1K

[joeblogs]

There are two issues here - will the controls work and will the plane hold together?

A number of Japanese planes were more vulnerable to compressibility than thier allied counterparts.  The controls would not have worked as expected at lower speeds than encountered for a Spit or F4u.  Even if they had worked, it's not clear an average pilot would have the strength to overcome the forces acting on such a larger elevator or ailerons.  The F6f-3 had this problem to a lesser degree.

As for structural integrity, American planes were simply over-engineered and had the weight to prove it.  

The spit was simply great engineering.  It had a wing spar designed like no other plane of its time, a set of concentric tubes inserted into each other.  This gave a great deal of strength for not much weight and very little space.  Over time the skin of the spitfire wing was gradually thickened to increase integrity.  The entire front of the wing was designed as a torsion box, much like a bomber design.  That said, the spitfire wing would twist a lot in high G turns, making it a difficult gun platform.

In terms of structural integrity, the differences between allied and Japenese fighters was due largely to the type of alumunum alloy used in the skin and its thickness.  

The Japanese planes used thinner skins to save weight and the alloy they used tended to become brittle over time from exposure to oxygen.  This was a metallurgy problem solved in the US in the early 1930s.  But Japan may not have had access to the the raw materials to correct this problem.  This was compounded by problems with Japanese paint, which tended to peel right off the skins...

-blogs

Originally posted by Karnak
I would expect that it probably had to do with poor quality control.

That is about the same weight as a Spitfire Mk IX, and the Spit certainly had no issues with shedding wings.

Also on the A6M, it wasn't a main spar failure that would hapen, it was the skin coming off.  That is why the thicker skin of the A6M5 allows for higher diving speeds.

Another point is that the P-51D had a wing shedding problem as well, and this is modeled in AH.

I would expect that you would have to watch your pull up Gs in the Ki.84 in AH the same way you must do that in the P-51D.

[Karnak]

joeblogs,

Keep in mind that the Japanese aluminum provided 40% more strength for the same weight as US aluminum.  They were aware of the degradation issue, but it simply didn't happen fast enough to affect these fighters during their expected operational lifetime.

[joeblogs]

You are probably right, except for all those army fighters in the South Pacific bases...

I suspect the bigger deal was compressibility.

-Blogs

Originally posted by Karnak
joeblogs,

Keep in mind that the Japanese aluminum provided 40% more strength for the same weight as US aluminum.  They were aware of the degradation issue, but it simply didn't happen fast enough to affect these fighters during their expected operational lifetime.

[davidpt40]

As for structural integrity, American planes were simply over-engineered and had the weight to prove it.

Except for the P51, which had problems with losing its wings AND tail.

[Jester]

Wasn't the problem with the Pony loosing it's tail because the early models had a part wooden or fabric tail?
Once the problem was found they went to an "all aluminum tail" and the problem stopped.

I flew the WARBIRDS KI-84 pretty regularly as a member of the 27th SENTAI and I don't ever recall ripping a wing off doing the above discribed maneuver.

[davidpt40]

Negative Andijig, P51s were losing their tails right up to the end of the war.  The problem became more apparent when mustangs were transferred to the Pacific.