Spit 8 vs Spit 9 Stall Characteristics

[SmokinLoon]

I find the Spit 9 to be a much more stable and smooth aircraft at low speeds than the Spit 8.  Other that the Spit 8 being slightly heavier due to a different engine and extra fuel tanks these planes are exactly the same, yes?  Same frame, same wings, same canopy, same weapons, etc.  With %50 fuel, the Spit 8 is just over 400lbs heavier.  Some of this is due to fuel but how much is due to the engine?

I've taken them both up w/ %50 fuel and gotten them both to a very similar weight (6900lbs each) and still the Spit 8 *seems* to stall out quicker, more "violently", and is much tougher to recover from vs the Spit 9.  Is it due to the fulcrum of the plane being more forward? 

Can anyone comment of this more precisely?  I'm posting this few a few of us in my squad as the lads from the UK are quite curious as well.

[Anaxogoras]

I find the Spit 9 to be a much more stable and smooth aircraft at low speeds than the Spit 8.  Other that the Spit 8 being slightly heavier due to a different engine and extra fuel tanks these planes are exactly the same, yes?  Same frame, same wings, same canopy, same weapons, etc.  With %50 fuel, the Spit 8 is just over 400lbs heavier.  Some of this is due to fuel but how much is due to the engine?

These two aircraft are more different than you think, but I'll let the experts explain the details.

[Kev367th]

I find the Spit 9 to be a much more stable and smooth aircraft at low speeds than the Spit 8.  Other that the Spit 8 being slightly heavier due to a different engine and extra fuel tanks these planes are exactly the same, yes?  Same frame, same wings, same canopy, same weapons, etc.  With %50 fuel, the Spit 8 is just over 400lbs heavier.  Some of this is due to fuel but how much is due to the engine?

I've taken them both up w/ %50 fuel and gotten them both to a very similar weight (6900lbs each) and still the Spit 8 *seems* to stall out quicker, more "violently", and is much tougher to recover from vs the Spit 9.  Is it due to the fulcrum of the plane being more forward? 

Can anyone comment of this more precisely?  I'm posting this few a few of us in my squad as the lads from the UK are quite curious as well.

Spit IX - Merlin 61 @ 1564hp, no wing tanks, standard rudder, standard ailerons.
Spit VIII - Merlin 66 @ 1580hp, wing tanks, broad chord (larger) rudder/tail, short span (smaller) ailerons.

Would imagine the C of G is further forward on the VIII.

[SmokinLoon]

I was led to believe that the models of Spit9/8 that we have in AH2 have the same airframe, ailerons, and rudder.

[Ack-Ack]

I was led to believe that the models of Spit9/8 that we have in AH2 have the same airframe, ailerons, and rudder.

I believe the VIII is more closely related to the XVI than the IX.  IIRC, the VIII is the same as the XVI with the only difference being the lack of clipped wings.


ack-ack

[Karnak]

I believe the VIII is more closely related to the XVI than the IX.  IIRC, the VIII is the same as the XVI with the only difference being the lack of clipped wings.


ack-ack

There are shared things between all three.  The Mk IX and Mk XVI are the closest in terms of airframe.  The Mk VIII and Mk XVI share an engine.  The Mk VIII and Mk XIV have the same ailerons.

[Kev367th]

I believe the VIII is more closely related to the XVI than the IX.  IIRC, the VIII is the same as the XVI with the only difference being the lack of clipped wings.


ack-ack

How could you forget the VIII has short span ailerons, and the XVI has full span ailerons?

Even the motors have a slight difference - XVI Merlin 266, VIII Merlin 66. The Merlin 266 having a FTH 1000ft higher than the Merlin 66.
Admittedly our XVI appears to based on an LFIX's Merlin 66 performance, not a Merlin 266.

[Ack-Ack]

How could you forget the VIII has short span ailerons, and the XVI has full span ailerons?

Easy mistake to make.  My usual view of a Spitfire is of a burning wreck, it's hard to see the difference in aileron spans when they're missing the ailerons and on fire.


ack-ack

[Bronk]

Easy mistake to make.  My usual view of a Spitfire is of a burning wreck, it's hard to see the difference in aileron spans when they're missing the ailerons and on fire.


ack-ack

You'd think with the air being perfectly clear at 25K+.... you could pick it out easier.

[Ack-Ack]

You'd think with the air being perfectly clear at 25K+.... you could pick it out easier.

You know how hard it is to spot those little suckers at 5k when I'm at 25k?  They look like ants!


ack-ack

[Bronk]

 

[Angus]

The short-span ailerons were an improvement, - I believe to eliminate flutter? The power transfer was AFIK different as well.
I also recall the wing being stiffer.
While a tad heavier, one test pilot referred to the VIII as better.
Performance data (pilots) from SE Asia give the aircraft 5 minutes to 20K and a top speed of 420. That is...nice

[Badboy]

My usual view of a Spitfire is of a burning wreck, it's hard to see the difference in aileron spans when they're missing the ailerons and on fire.

But a well flown Spitfire is quite another story, I'm sure you would agree

Badboy

[SgtPappy]

It was Jeff. Quill that referred to the Spitfire VIII as the best Merlin-engined Spitfire.

Also, the Spitfire VIII has 1,720 hp, max plus a bit of extra fuel in the lower tank and in the wings.

[Angus]

Quill it was...
Some glimpses of his words:
"It also featured ailerons on which the long overhang outboard of the outer hinge was shortened in order to increase the stiffness of the aileron structure"
"We then had an excellent aeroplane which was very pleasant to handle and with performance as good as the Mk IX, with many other advantages added on."