F4U in Europe

FLYBOYJ · Nov 29, 2021

NevadaK said:
The last couple races have pretty much been all stock. I moved up to Reno in 2016 and had an opportunity to see Voodoo and Strega go at it, but the modified have all pretty much retired. I typically go on Friday for the smaller crowd and ability to get around the pits better. My connection with the races goes back to the seventies. My family is from Kalamazoo, Michigan and my step-father who was a professional helicopter pilot was acquainted with Gunther Balz who won the unlimited class in Miss Roto Finish in 1972. View attachment 649877

I crewed with 2 jet teams 2007-2009 and then 2014 and 2015. It was a great experience as I had my run of the flight line. When my jet was down or I had some idle time (which was almost never) I would stroll over to the unlimiteds and chat with some of the crew members and crew chiefs there. Those 3 days for me were like working in a combat environment, the only difference I had as opposed to some of my unlimited brethren was if we blew an engine, we were done where some of the unlimited gold guys had a back up motor available.

Schweik · Nov 29, 2021

NevadaK said:
The last couple races have pretty much been all stock. I moved up to Reno in 2016 and had an opportunity to see Voodoo and Strega go at it, but the modified have all pretty much retired. I typically go on Friday for the smaller crowd and ability to get around the pits better. My connection with the races goes back to the seventies. My family is from Kalamazoo, Michigan and my step-father who was a professional helicopter pilot was acquainted with Gunther Balz who won the unlimited class in Miss Roto Finish in 1972. View attachment 649877

That is a pretty bird. Looks fast as hell.

BiffF15 · Nov 29, 2021

NevadaK said:
The last couple races have pretty much been all stock. I moved up to Reno in 2016 and had an opportunity to see Voodoo and Strega go at it, but the modified have all pretty much retired. I typically go on Friday for the smaller crowd and ability to get around the pits better. My connection with the races goes back to the seventies. My family is from Kalamazoo, Michigan and my step-father who was a professional helicopter pilot was acquainted with Gunther Balz who won the unlimited class in Miss Roto Finish in 1972. View attachment 649877

I can't imagine what Gunthers call sign would have been in a fighter squadron...

FLYBOYJ · Nov 29, 2021

BiffF15 said:
I can't imagine what Gunthers call sign would have been in a fighter squadron...

The last year I crewed at Reno my pilot's call sign was "Killer," guess how he got that one!

wuzak · Nov 29, 2021

FLYBOYJ said:
Those 3 days for me were like working in a combat environment, the only difference I had as opposed to some of my unlimited brethren was if we blew an engine, we were done where some of the unlimited gold guys had a back up motor available.

Did your team blow an engine?

FLYBOYJ · Nov 29, 2021

wuzak said:
Did your team blow an engine?

No, but we did have a few hot starts and had some FCU issues when I was crewing an L39. Thankfully one of the best L39 mechanics in the US happened to be on the field and helped us.

DarrenW · Nov 29, 2021

Schweik said:
How much does lift coefficient vary between Spit, F6F, F4U, Bf 109, P-51 etc.? How much of a difference does it typically make compared to Wing Loading?

I've seen NACA reports comparing the Spitfire Mk.V, F6F, F4U, P-51, and the F6F seems to have the greatest lift coefficient at all angles of attack. The F4U was next, followed by the Spitfire, and lastly the P-51. By the look of the airfoil used by the Bf 109 I think it would rate similar to the Spitfire, but the leading edge slats employed by the German fighter could have been a game changer under certain circumstances. Lastly, from what I understand the laminar inspired wing section of the P-51 aided in the reduction of drag (by how much I do not know) and also helped delay the onset of compressibility but conversely it had a negative effect on lift when compared to the 'turbulent airfoils' of the other four mentioned aircraft.

Hopefully someone here with more knowledge on the subject can expand on this...

GregP · Nov 29, 2021

The slats on the Bf 109 basically covered the ailerons and occupied about 1/3 of the span. They were not to lower the stall speed, though they might have done so by a few knots. They were there to keep the airflow over the ailerons attached through stall for roll control. Most of the wing is unslatted.

drgondog · Nov 30, 2021

DarrenW said:
I've seen NACA reports comparing the Spitfire Mk.V, F6F, F4U, P-51, and the F6F seems to have the greatest lift coefficient at all angles of attack. The F4U was next, followed by the Spitfire, and lastly the P-51. By the look of the airfoil used by the Bf 109 I think it would rate similar to the Spitfire, but the leading edge slats employed by the German fighter could have been a game changer under certain circumstances. Lastly, from what I understand the laminar inspired wing section of the P-51 aided in the reduction of drag (by how much I do not know) and also helped delay the onset of compresibilility but conversely it had a negative effect on lift when compared to the 'turbulent airfoils' of the other four mentioned aircraft.

Hopefully someone here with more knowledge on the subject can expand on this...

Greg posed the primary reason for slats on the Bf 109 - namely roll authority at low speed. The reason slats were considered at all was a desire to reduce the small contribution to Induced Drag that a convention wing twist would cause. It is important for near stall conditions but took great skill by the 109 pilot to fly in a tight bank with asymmerical lift - a condition in which one wing (high wing) stalls out independent of the slats - forcing a snap roll. Some (very few) LW aces mastered the slats and were successful at exploiting the higher CL enabled by slats in medium speed turns.

The Bf 109 airfoil was closer in design shape to the NACA 23xxx of the F6F and F4U with nice combinations of L/D across wide span of AoA - but less than P-51 wing. The F6F had the fattest airfoil - and was optimzed for climb, turn and low speed aero stall for carrier ops. That said, the F6F and F4U had parasite drag 50% higher than P51. Equally the NAA/NACA 45-100 pushed the max T/C to 37.5% compared to ~25% for NACA 23xxx - which dramatically delayed onset Mcr - and the step drag rise associated with Mach contributions to total Cd.

Note that F4U exhibited nasty low speed stall characteristics due to the upwash on the inboard wing section - making a necessary add of a spoiler addition to the downwash section to precipitate earlier stall to match -

The Spitfire had the thinnest wing of all the major fighter wings which was useful in delaying Mcr also.

A point should be made that Excess Hp Available is extremely important in Turn (and Climb and acceleration) Performance. When Drag > Thrust the turning aircraft may not maintain altitude in the turn. Ditto for Climb. One of the reasons that a P-51B/D was a significant dogfighter was that when a 109/190 was maxed out in top level speed (~400 mph at 22K), the Mustang was still capable of accelerating to 430mph at 24K and 440 mph at 29K (~) and also available for better climb performance. That said, the P-51B/D gave up some of this advantage at medium and low speeds.

CL was, and is important in Performance Calcs but as in all cases other attributes such as roll response and acceleration and dive speed and zoom climb were more important in air combat - recall that a ery high % of air to air victims never saw their attacker.

DarrenW · Nov 30, 2021

drgondog said:
Note that F4U exhibited nasty low speed stall characteristics due to the upwash on the inboard wing section - making a necessary add of a spoiler addition to the downwash section to precipitate earlier stall to match -

Yeah, that inverted gull wing caused less interference drag between wing root and fuselage but in turn had a negative effect on lift. Another great example of how everything related to aircraft design is a compromise.

And as always thanks for interjecting your knowledge in this area, it was very helpful.

pbehn · Nov 30, 2021

DarrenW said:
I've seen NACA reports comparing the Spitfire Mk.V, F6F, F4U, P-51, and the F6F seems to have the greatest lift coefficient at all angles of attack. The F4U was next, followed by the Spitfire, and lastly the P-51. By the look of the airfoil used by the Bf 109 I think it would rate similar to the Spitfire, but the leading edge slats employed by the German fighter could have been a game changer under certain circumstances. Lastly, from what I understand the laminar inspired wing section of the P-51 aided in the reduction of drag (by how much I do not know) and also helped delay the onset of compresibilility but conversely it had a negative effect on lift when compared to the 'turbulent airfoils' of the other four mentioned aircraft.

Hopefully someone here with more knowledge on the subject can expand on this...

The P-51 could use a small amount of flap (8 degrees as I remember) if involved in a turning fight.

drgondog · Nov 30, 2021

pbehn said:
The P-51 could use a small amount of flap (8 degrees as I remember) if involved in a turning fight.

Yes, but - it was good for a sharp corner break to pull lead, but lot of energy lost with ensuing drag.

pbehn · Nov 30, 2021

drgondog said:
Yes, but - it was good for a sharp corner break to pull lead, but lot of energy lost with ensuing drag.

As I understand it the Bf 109s aerodynamics were poor, apart from it being small, but in some situations you want to be the "loser" and slow down faster than the other guy. Being able to choose how much energy you keep or lose must be a plus, if you know what you are doing?

swampyankee · Dec 1, 2021

pbehn said:
As I understand it the Bf 109s aerodynamics were poor, apart from it being small, but in some situations you want to be the "loser" and slow down faster than the other guy. Being able to choose how much energy you keep or lose must be a plus, if you know what you are doing?

Any piston-engined aircraft with constant speed props has a large, built-in airbrake: reducing the throttle while keeping rpm constant is likely to produce a lot of drag.

Peter Gunn · Dec 1, 2021

drgondog said:
Greg posed the primary reason for slats on the Bf 109 - namely roll authority at low speed. The reason slats were considered at all was a desire to reduce the small contribution to Induced Drag that a convention wing twist would cause. It is important for near stall conditions but took great skill by the 109 pilot to fly in a tight bank with asymmerical lift - a condition in which one wing (high wing) stalls out independent of the slats - forcing a snap roll. Some (very few) LW aces mastered the slats and were successful at exploiting the higher CL enabled by slats in medium speed turns.

The Bf 109 airfoil was closer in design shape to the NACA 23xxx of the F6F and F4U with nice combinations of L/D across wide span of AoA - but less than P-51 wing. The F6F had the fattest airfoil - and was optimzed for climb, turn and low speed aero stall for carrier ops. That said, the F6F and F4U had parasite drag 50% higher than P51. Equally the NAA/NACA 45-100 pushed the max T/C to 37.5% compared to ~25% for NACA 23xxx - which dramatically delayed onset Mcr - and the step drag rise associated with Mach contributions to total Cd.

Note that F4U exhibited nasty low speed stall characteristics due to the upwash on the inboard wing section - making a necessary add of a spoiler addition to the downwash section to precipitate earlier stall to match -

The Spitfire had the thinnest wing of all the major fighter wings which was useful in delaying Mcr also.

A point should be made that Excess Hp Available is extremely important in Turn (and Climb and acceleration) Performance. When Drag > Thrust the turning aircraft may not maintain altitude in the turn. Ditto for Climb. One of the reasons that a P-51B/D was a significant dogfighter was that when a 109/190 was maxed out in top level speed (~400 mph at 22K), the Mustang was still capable of accelerating to 430mph at 24K and 440 mph at 29K (~) and also available for better climb performance. That said, the P-51B/D gave up some of this advantage at medium and low speeds.

CL was, and is important in Performance Calcs but as in all cases other attributes such as roll response and acceleration and dive speed and zoom climb were more important in air combat - recall that a ery high % of air to air victims never saw their attacker.

I dunno, I see a lot of ancedotal rhetoric here.

Sources?

...

Shortround6 · Dec 1, 2021

pbehn said:
Being able to choose how much energy you keep or lose must be a plus, if you know what you are doing?

Well, you are going to lose energy a lot quicker than you can get it back so you have to have a 'really' good idea of what you are doing.

You also need some rules so some interloper/s don't spoil the 'plan' by mucking about with a 'dual'.

NTGray · Dec 1, 2021

swampyankee said:
Any piston-engined aircraft with constant speed props has a large, built-in airbrake: reducing the throttle while keeping rpm constant is likely to produce a lot of drag.

Does it really work that way, or will the prop "semi-feather" to achieve zero net pull or drag? Asking because I don't know.

BiffF15 · Dec 1, 2021

NTGray said:
Does it really work that way, or will the prop "semi-feather" to achieve zero net pull or drag? Asking because I don't know.

NTGray,

On multi engine aircraft there is the option to feather (not all were made like that back in the day). However, I don't think SE WW2 fighters had that ability. I could be wrong, but the windmilling prop would be used to restart the engine hence no need for the ability to feather.

Cheers,
Biff

pbehn · Dec 1, 2021

BiffF15 said:
NTGray,

On multi engine aircraft there is the option to feather (not all were made like that back in the day). However, I don't think SE WW2 fighters had that ability. I could be wrong, but the windmilling prop would be used to restart the engine hence no need for the ability to feather.

Cheers,
Biff

The Spitfire used to make high speed dives post war had to be fitted with a fully feathering prop to do it. It made no difference, the prop came off anyways.

BiffF15 · Dec 1, 2021

pbehn said:
The Spitfire used to make high speed dives post war had to be fitted with a fully feathering prop to do it. It made no difference, the prop came off anyways.

Nothing like stepping to fly a plane where you are expecting the prop to come off at some point…

F4U in Europe

"THE GREAT GAZOO"

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Tech Sergeant

"THE GREAT GAZOO"

Captain

"THE GREAT GAZOO"

Staff Sergeant

Major

Major

Staff Sergeant

Colonel

Major

Colonel

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Airman 1st Class

Tech Sergeant

Colonel

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