XP-82 as a racer ?

[Guest]

Re: XP-82 as a racer ?

I am, by NO stretch of the imagination, an aerodynamicist (had to look that up to know how to spell it!), but curious.

Couple things for all the brainiacs on the thread:

Curious why there are no outboard horizontal stabs on this ship. Only the center span between the booms.

Second, I thought I read somewhere some years ago that initially the props turned such that they "met" at the centerline in an upward fashion (starboard spinning clockwise, port spinning counter-clockwise). They found that this wasn't such a good idea and switched to meeting in a downward fashion (starboard spinning counter-clockwise, port spinning clockwise).

Something to do with propwash flowing over the center wing area?

Again...I'd make a aerodynamicist about as well as Bill Clinton would make a monk...just sayin'.

[Leo]

Re: XP-82 as a racer ?

In light of everything we are hearing lately, he'd make a GREAT priest though...

Couldn't resist.

The P-38 originally had the props turning so the upward stroke was inboard. Supposedly this was so torque would help lift the opposite wing in an engine-out situation. I don't recall if the direction changed during production, would have to look it up.
Maybe P-82 had a similar reason?

[Guest]

Re: XP-82 as a racer ?

In light of everything we are hearing lately, he'd make a GREAT priest though...

Couldn't resist.

The P-38 originally had the props turning so the upward stroke was inboard. Supposedly this was so torque would help lift the opposite wing in an engine-out situation. I don't recall if the direction changed during production, would have to look it up.
Maybe P-82 had a similar reason?

Funniest line of the week right there!

[toldjaso]

Re: XP-82 as a racer ?

In light of everything we are hearing lately, he'd make a GREAT priest though...

Couldn't resist.

The P-38 originally had the props turning so the upward stroke was inboard. Supposedly this was so torque would help lift the opposite wing in an engine-out situation. I don't recall if the direction changed during production, would have to look it up.
Maybe P-82 had a similar reason?

(Prop rotation is as viewed by the pilot looking out the windshield). All the single-engine American fighters had clockwise turning props.

The first P-38 had both propellers turning inward toward the fuselage at the top of the propeller arc.(No critical engine).

Flight tests then showed the P-38 about 100 MPH slower than expected. They figured out that the prop wash was causing too much drag over the horizontal stabilizer. They swapped the engines left and right, and picked up the speed. The downside was now the plane had two critical engines, meaning if either engine quit the other one could flip the plane on it's back from the propeller torque. So now the right engine was standard rotation, and the left engine and prop were left-hand rotation.

I guess the center pod style fuselage on the P-38 caused enough difference with the airflow from the prop wash as compared to the P-82, because they had a different issue with the center section being stalled out by the prop wash on the P-82 when they had the props turning outward (like the P-38 has). So with the P-82, when the prototype would not take off, they had to reverse the engine installations and put the clockwise engine on the left and the counter-clockwise engine on the right, just the opposite of the fix for the P-38.

[toldjaso]

Re: XP-82 as a racer ?

I am, by NO stretch of the imagination, an aerodynamicist (had to look that up to know how to spell it!), but curious.

Couple things for all the brainiacs on the thread:

Curious why there are no outboard horizontal stabs on this ship. Only the center span between the booms.

Second, I thought I read somewhere some years ago that initially the props turned such that they "met" at the centerline in an upward fashion (starboard spinning clockwise, port spinning counter-clockwise). They found that this wasn't such a good idea and switched to meeting in a downward fashion (starboard spinning counter-clockwise, port spinning clockwise).

Something to do with propwash flowing over the center wing area?

Again...I'd make a aerodynamicist about as well as Bill Clinton would make a monk...just sayin'.

As for the horizontal stab outboard of the booms, they just did not need it.
Tony LeVier raced a P-38 and they removed the outboard horizontals.
The Cessna 337 and Anderson Greenwood AG-14 were the same way, with no outside horizontals.

[Guest]

Re: XP-82 as a racer ?

As for the horizontal stab outboard of the booms, they just did not need it.
Tony LeVier raced a P-38 and they removed the outboard horizontals.
The Cessna 337 and Anderson Greenwood AG-14 were the same way, with no outside horizontals.

Thanks for the insight. Always was a headscratcher for me. Never ceases to amaze me what an engineer can come up with and ultimately what a pilot and flight dynamicists can render useless!

Cheers!

[AAFO_WSagar]

Re: XP-82 as a racer ?

The first P-38 had both propellers turning inward toward the fuselage at the top of the propeller arc.(No critical engine)

TJS, I don't know if everyone here knows your qualifications, I do and thank you for stopping by and contributing!

[Leo]

Re: XP-82 as a racer ?

Thanks Toldjaso.
I had it backwards!
It's what happens when I try and be smart at work...

[toldjaso]

Re: XP-82 as a racer ?

TJS, I don't know if everyone here knows your qualifications, I do and thank you for stopping by and contributing!

Aw shucks Wayne, I just have some experience.

Experience is that thing you get when you didn't get what you really wanted.