Vultee XP-68 and other « Swoose Goose » variants

[Vietcong]

Can I also ask for the Vultee XP-68,the improvement version of Vultee XP-54

 

[Vietcong]

I think the XP-54 is different to XP-68 because the XP-54 is a singlr prop pusher when the XP-68 is contra rotating prop like Davis manta fighter second design.

 

[Tophe]

Here is a summary of what I made for the What-if-modeller forum: XP-68, XP-68B, XP-68J slanting views. I would be glad to correct if someone has a more reliable source ;D

 

[Stargazer]

Tophe, only the first view represents a real Vultee project, right? Aren't the rest of your invention?

 

[Tophe]

Yes, the XP-54 comes from a 3-view drawing, while the others are imagined different from the mention that the XP-68 had a double-propeller (and maybe an air-coolled engine - with air scoops making almost easy a jet derivative).

 

[Vietcong]

Here is a summary of what I made for the What-if-modeller forum: XP-68, XP-68B, XP-68J slanting views. I would be glad to correct if someone has a more reliable source ;D

Thanks Tophe

 

[elmayerle]

From what I've read, XP-68 = XP-54 re-engined with a Wright "Tornado" engine (same as XP-69").

 

[lark]

Indeed the same airframe ,but with the 'Tornado' engine.
From what I found about ,not much despite 20years of search, is that
the airframe should be changed with large airscoops to provide cooling flow
for the large engine.In all the books and mag.articles I read ,it is not mentioned were
the scoops should be placed...

 

[elmayerle]

Since the R-2160 was liquid-cooled, would it have needed that much more in the way of cooling scoops? The Lycoming engine already in the XP-54 was also liquid-cooled and I can't see needing to increase the radiators that much over what the XH2470 required (mind you, there might be in the deeper details, but I don't see any at first glance).

 

[lark]

Yes indeed I know the Wright engine was liquid cooled but if you see
the fairly large belly air intake for the Tornado on the projected Republic XP-69
than it might be the same for the XP-68...

 

[elmayerle]

And I'm arguing that the cooling system for the H2470 should be adequate for the R2160 unless one puts out rather more thermal energy than the other. WIthout getting too analytical about it, the cooling intakes on the XP-54 appear to have adequate area to match the single intake on the XP-69.

 

[Apteryx]

And I'm arguing that the cooling system for the H2470 should be adequate for the R2160 unless one puts out rather more thermal energy than the other. WIthout getting too analytical about it, the cooling intakes on the XP-54 appear to have adequate area to match the single intake on the XP-69.

In his book, Tornado, Kimble McCutcheon discusses negotiations between the Air Force and Vultee (he draws on the USAAF's Case History of the XP-54). Vultee was more interested in getting the XP-54 in the air at an early date with the Lycoming engine than in adapting it to handle the even heavier Tornado. The Air Force prevailed, however:
"Vultee was directed to build the XP-54 to accept either the XH-2470 or the Wright Tornado. Both engines were to be turbosupercharged. The airframe was to be stressed to handle the 2,500 hp of the Tornado. Coolant radiators, oil coolers, and other accessories were also to be sized to handle a 2,500 hp powerplant. The first ship was to be Lycoming powered and was to fly in June of 1942. The second was to be Wright powered and anticipated delivery of the Tornado during July of 1942. In July of 1941, the USAAF assigned the designation XP-68 to the project."

The above would seem to indicate that the XP-68 prototype would have looked very much like the XP-54, excepting the propellers.

--Ian

 

[Vietcong]

Here is one of the artist impression of the XP-68 that I found in anigrand model site

 

[hesham]

Hi,

Vultee Model-83 was a single seat fighter aircraft, being a development
version of the aircraft Vultee Model 48 Vanguard.It remained only a
project,has anyone a more info about it.

 

[hesham]

Hi,

the Vultee Model 70-2 had a single-seat,single X-1800 engine,
twin fuselage booms,twin tail,a 40-foot inverted gull wing and
tricycle landing gear.

http://books.google.com.eg/books?id=FW_50wm8VnMC&pg=PA526&dq=curtiss+P.249C&hl=ar&ei=JPCpTOGxEoeWOu7W4ZcM&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCcQ6AEwAQ#v=onepage&q=curtiss%20P.249C&f=true

 

[Stargazer]

Topic split from old "piston fighters" thread.

The topic on the XP-54 « Swoose Goose » prototypes can be found here:
http://www.secretprojects.co.uk/forum/index.php/topic,8956.0

 

[XP67_Moonbat]

I just read in Convair Advanced Designs II, in the XP-54 chapter, that a jet-powered version was considered during the wrangling over power plants. Is there and pictures of this jet-powered XP-54?

 

[blackkite]

Hi! XP-68.
I can see radiator air intake at the bottom of the fuselage.
It's a normal design based on XP-54 failure?
The fuselage of XP-68 was not so long because......as you already know.

 

[lark]

Do you have a source of the model 78 cutaway drawing Blackkite

 

[Antonio]

American Secret Pusher Fighters of World War II
Gerald H. Balzer
pg 61

 

[Apteryx]

Hi! XP-68.
I can see radiator air intake at the bottom of the fuselage.
It's a normal design based on XP-54 failure?
The fuselage of XP-68 was not so long because......as you already know.

Blackkite, the source for your "XP-68" drawing (US Experimental and Prototype Aircraft Projects) is very confusing. The scale bar on the top drawing, supposedly an XP-68 version, makes its wingspan less than 30 feet, compared to 54 feet for the XP-54. The Tornado-powered plane has a stated projected gross weight, 8500 lb, which is less than a third of the final gross weight of the XP-54 with an engine that weighed as much as the Tornado. The idea that Vultee would return to an earlier design and stuff a larger, heavier engine in it, rather than install it in a plane already built, and which was designed to accept it, is hard to understand. I think the author of this book has misread the history.

--Ian

 

[blackkite]

Oh thanks a lot for very sharp opinion.
I will check your opinion. Give me time.

 

[Grey Havoc]

Publisher foul-up perhaps?

 

[blackkite]

Hi! XP-68.
I can see radiator air intake at the bottom of the fuselage.
It's a normal design based on XP-54 failure?
The fuselage of XP-68 was not so long because......as you already know.

Blackkite, the source for your "XP-68" drawing (US Experimental and Prototype Aircraft Projects) is very confusing. The scale bar on the top drawing, supposedly an XP-68 version, makes its wingspan less than 30 feet, compared to 54 feet for the XP-54. The Tornado-powered plane has a stated projected gross weight, 8500 lb, which is less than a third of the final gross weight of the XP-54 with an engine that weighed as much as the Tornado. The idea that Vultee would return to an earlier design and stuff a larger, heavier engine in it, rather than install it in a plane already built, and which was designed to accept it, is hard to understand. I think the author of this book has misread the history.

--Ian

Hmmm.......You mean this drawing? Tail stabilizer looks like P-38's one.
Source : U.S.EXPERIMENTAL & PROTOTYPE AIRCRAFT PROJECTS FIGHTERS 1939-1945, SPECIALTY PRESS, Bill Norton, ISBN 97815800710093

 

[Apteryx]

Hmmm.......You mean this drawing? Tail stabilizer looks like P-38's one.
Source : U.S.EXPERIMENTAL & PROTOTYPE AIRCRAFT PROJECTS FIGHTERS 1939-1945, SPECIALTY PRESS, Bill Norton, ISBN 97815800710093

An interesting rendering! This is the earliest picture of the model 84, aka XP-54, that I have seen. It looks like the first step away from the Model 78--larger but otherwise almost identical. Most interesting new feature is the contra prop--this drawing would have been submitted when the P&W X-1800 was still planned for the plane. I guess Vultee was concerned from early on about the size of a single prop (12 ft dia. on the prototypes).

It was another 11 months before Vultee let the Air Force know that they'd have to fit a contra prop on the P-68 because they couldn't accommodate the power of the Tornado otherwise.

Having looked at several references in the last couple of days, I will admit that the history is just confusing! Two different books state that the Model 78 was being developed as the XP-68. It makes no sense, though! ???

 

[blackkite]

Apteryx-san!
Your image for XP-68 is like this?

 

[Apteryx]

Apteryx-san!
Your image for XP-68 is like this?

Indeed, yes.

 

[blackkite]

Ummm.........Mysterious aircraft exist even in the United States. ;D
I find some XP-68 images in internet.

 

[Apteryx]

Ummm.........Mysterious aircraft exist even in the United States. ;D
I find some XP-68 images in internet.

Perhaps our friend Tophe can lend his opinion on the distinctive features of these renderings.

Just to recap: the Wright Tornado never got off the test stand; no aircraft manufacturers ever received one to finish provision for installation. The XP-54 airframe HAD been designed to accept its dimensions, weight, and cooling demands (see my previous post in this thread), and thus, in an alternate timeline, the XP-68 eventually would have flown looking like the XP-54, with the exception of either a contra-prop or, perhaps, a longer undercarriage.

Of course, we can speculate forever on what a real-world P-68 would have looked like, since the development process takes many twists and turns, but that's how the prototype would have looked on roll-out.

 

[RyanC]

From RG342 P27, Box 6797 today at NARA II:

ARMY AIR FORCES
ENGINEERING DIVISION MEMORANDUM REPORT

Date April 17, 1943

SUBJECT: Final Report on XP-68 Airplane

SERIAL No. ..ENG-50-855
Contract No.....none.
Expenditure Order No.430
Purchase Order No. ...none

A. Purpose.

1. To record the brief facts relating to the XP-68 airplane which was never built but for which a model designation was assigned and therefore appears on the historical records as the model designation reserved for the contemplated construction of the XP-68 airplane by the Vultee Corporation.

B, Factual Data.

1. The XP-68 airplane is closely related to the two (2) XP-54 airplanes procured on contract AC-15019, in fact, the XP-68 was at one time considered as the model designation for one of the two (2) XP-54 airplanes equipped with a Wright Tornado R-2160 engine instead of the incoming H-2470-1 engine. The mock-up of the XP-54 in its original form as a medium altitude, 11000 pound, Lycoming H-2470 engine equipped airplane, was inspected in May, 1941. Following the mock-up inspection on May 23, 1941, General Echols and General Kenny directed that the XP-54 airplane be equipped with turbo superchargers. The follow up of this directive as well as the incorporation of mock-up changes including the application of a pressurized cabin all of which were of such magnitude that collectively they called for a redesign of the airplane. Consequently, in July, 1941, it was definitely decided to completely redesign the XP-54 airplane increasing the wing area from 293 square feet to 456 square feet and the weight from 11000 to 16145 pounds. At the time of negotiations for this redesign the application of the Wright Tornado R-2160 engine to certain experimental airplanes was receiving serious consideration and the redesign presented the opportunity to explore the possibilities with respect to this airplane.

2. It was seriously considered in connection with this procurement of the second airplane, which was obtained under a supplemental agreement to contract AC-15019, to install the Tornado engine in one of the two airplanes, but this resulted only in the allocation of sufficient space for the installation of a Tornado engine in either of the two airplanes. The reason for dropping the Tornado engine was poor performance estimates based mainly on the fact that the Tornado engine involved a 4 to 1 propeller reduction gear whereas the design called for a reduction gear of approximately 2 to 1 with a dual rotation propeller. In conferences occurring during September, 1941, it was determined that it would be practically impossible to use the Tornado engine due to the fact that the gear ratio required a propeller of larger diameter than could be swung between the booms. As a result of there conferences, it was decided to proceed with the installation of the Lycoming H-2470-1 engine in both XP-54 airplanes with space provisions only for the possible future application of the Tornado R-2160 engine with two speed gearing and opposite rotating propellers. The airplane however, incorporates sufficient cooling for an engine developing 2500 horsepower at a critical altitude of 30,000 feet in anticipation of the application of engines other than the Lycoming H-2470.

3· Briefly stated, the model designation XP-68 was merely reserved for the contemplated Tornado engine version of the XP-54 airplane.

C. Conclusions.

1. None.

D. Recommendations

1. None. This report prepared for record purposes only.

Prepared by PAUL MB. SMITH

Approved by H.Z. BOGERT, Colonel, AC. Technical Staff

 

[blackkite]

From RG342 P27, Box 6797 today at NARA II:

ARMY AIR FORCES
ENGINEERING DIVISION MEMORANDUM REPORT

Date April 17, 1943

SUBJECT: Final Report on XP-68 Airplane

SERIAL No. ..ENG-50-855
Contract No.....none.
Expenditure Order No.430
Purchase Order No. ...none

A. Purpose.

1. To record the brief facts relating to the XP-68 airplane which was never built but for which a model designation was assigned and therefore appears on the historical records as the model designation reserved for the contemplated construction of the XP-68 airplane by the Vultee Corporation.

B, Factual Data.

1. The XP-68 airplane is closely related to the two (2) XP-54 airplanes procured on contract AC-15019, in fact, the XP-68 was at one time considered as the model designation for one of the two (2) XP-54 airplanes equipped with a Wright Tornado R-2160 engine instead of the incoming H-2470-1 engine. The mock-up of the XP-54 in its original form as a medium altitude, 11000 pound, Lycoming H-2470 engine equipped airplane, was inspected in May, 1941. Following the mock-up inspection on May 23, 1941, General Echols and General Kenny directed that the XP-54 airplane be equipped with turbo superchargers. The follow up of this directive as well as the incorporation of mock-up changes including the application of a pressurized cabin all of which were of such magnitude that collectively they called for a redesign of the airplane. Consequently, in July, 1941, it was definitely decided to completely redesign the XP-54 airplane increasing the wing area from 293 square feet to 456 square feet and the weight from 11000 to 16145 pounds. At the time of negotiations for this redesign the application of the Wright Tornado R-2160 engine to certain experimental airplanes was receiving serious consideration and the redesign presented the opportunity to explore the possibilities with respect to this airplane.

2. It was seriously considered in connection with this procurement of the second airplane, which was obtained under a supplemental agreement to contract AC-15019, to install the Tornado engine in one of the two airplanes, but this resulted only in the allocation of sufficient space for the installation of a Tornado engine in either of the two airplanes. The reason for dropping the Tornado engine was poor performance estimates based mainly on the fact that the Tornado engine involved a 4 to 1 propeller reduction gear whereas the design called for a reduction gear of approximately 2 to 1 with a dual rotation propeller. In conferences occurring during September, 1941, it was determined that it would be practically impossible to use the Tornado engine due to the fact that the gear ratio required a propeller of larger diameter than could be swung between the booms. As a result of there conferences, it was decided to proceed with the installation of the Lycoming H-2470-1 engine in both XP-54 airplanes with space provisions only for the possible future application of the Tornado R-2160 engine with two speed gearing and opposite rotating propellers. The airplane however, incorporates sufficient cooling for an engine developing 2500 horsepower at a critical altitude of 30,000 feet in anticipation of the application of engines other than the Lycoming H-2470.

3· Briefly stated, the model designation XP-68 was merely reserved for the contemplated Tornado engine version of the XP-54 airplane.

C. Conclusions.

1. None.

D. Recommendations

1. None. This report prepared for record purposes only.

Prepared by PAUL MB. SMITH

Approved by H.Z. BOGERT, Colonel, AC. Technical Staff

"3· Briefly stated, the model designation XP-68 was merely reserved for the contemplated Tornado engine version of the XP-54 airplane."
Thanks!! Great information. B)

https://en.wikipedia.org/wiki/Lycoming_H-2470
https://en.wikipedia.org/wiki/Wright_R-2160_Tornado

 

[Apteryx]

From RG342 P27, Box 6797 today at NARA II:

...

1. The XP-68 airplane is closely related to the two (2) XP-54 airplanes procured on contract AC-15019, in fact, the XP-68 was at one time considered as the model designation for one of the two (2) XP-54 airplanes equipped with a Wright Tornado R-2160 engine instead of the incoming H-2470-1 engine. The mock-up of the XP-54 in its original form as a medium altitude, 11000 pound, Lycoming H-2470 engine equipped airplane, was inspected in May, 1941. Following the mock-up inspection on May 23, 1941, General Echols and General Kenny directed that the XP-54 airplane be equipped with turbo superchargers. The follow up of this directive as well as the incorporation of mock-up changes including the application of a pressurized cabin all of which were of such magnitude that collectively they called for a redesign of the airplane. Consequently, in July, 1941, it was definitely decided to completely redesign the XP-54 airplane increasing the wing area from 293 square feet to 456 square feet and the weight from 11000 to 16145 pounds...

Good stuff-thanks for posting! I'll note, just for clarity, that the larger wing area cited is the actual listed wing area of the XP-54s built, and their weights wound up substantially over that spec'ed above.

 

[Grey Havoc]

View: https://www.youtube.com/watch?v=EhKenDU-dyY