NAVY DEPARTMENT
BUREAU OF AERONAUTICS
WASHINGTON 28, D. C

5 APR 1949

CONFIDENTIAL

MEMORANDUM

To:

Chief, Bureau of Aeronautics

Subject:

Model VF Seaplane Night Fighter - Recommendation on Design Competition

Reference:

See Enclosure (A).



Enclosures:

(A) List of References.
(B) Performance Summary.
(C) Vmax vs. Altitude.
(D) R/C vs. Altitude.
(E) Vmax and 2"g" Vs vs. Alt.
(F) Cost Comparison.
(G) General Arrangement Sketches.

1. In reference (a), the Bureau of Aeronautics informed CNO that preliminary investigative work on seaplane fighters was approaching a conclusion and that further work was not warranted unless actual development of an airplane was contemplated. Reference (b) advised BuAer that the development of a seaplane fighter was desired, and requested the start of the program with fiscal 1949 funds. A conference on 9 June 1948 resulted in the writing of outline specification OS-114 dated June 1948 for a single place, interceptor type seaplane fighter. A second conference on 29 June 1948 was called to revise these requirements and to determine criteria which would result in a two place fighter with a gross weight of approximately 30,000 lbs. A third series of conferences on 19 - 20 August 1948 resulted in establishment of the basic requirements for a seaplane night fighter, which after a bureau design study to insure practicability, were forwarded to CNO by reference (c) for concurrence. Reference (d) reaffirmed the interest of the CNO in the project and expressed satisfaction with the proposed requirements. Reference (e) requested informal design proposals in accordance with the requirements of outline specification OS-116 dated 21 Sept. 1948 from sixteen manufacturers. Proposals were received only from Consolidated-Vultee and Curtiss-Wright by references (f) through (i), while the remaining manufacturers notified the bureau of their intention not to submit designs by references (j) through (v).

2. As expected, ConVair submitted the blended wing and hull configuration known as SKATE, the lines of which have been developed under a Navy hydrodynamic research contract. The proposed version of SKATE is powered with two J40-10 engines with afterburners, and incorporates retractable spray dams, a retractable step, full power irreversible control system with artificial feel, an all moving horizontal tail and a staggered side by side crew arrangement with the radar operator lower than the pilot. This general configuration has been thoroughly tested hydrodynamically and is considered satisfactory.

3. Curtiss submitted a single engine design with a retractable hydro-ski powered with a J40-10 engine and afterburner. The hydro-ski principle has been tested at the NACA and Stevens Institute towing tanks and in flight by Edo on a JRP airplane under an Air Force research contract. The single hydro-ski has very attractive possibilities particularly as regards rough water operation, but still possesses some unknowns in the transition stage and may introduce lateral control problems at low airspeeds after the airplane gets up on the ski with the wing tip floats clear of the water. This may be far more evident on the Curtiss proposal which has a take-off speed of 154.5 knots than it was on the JRF with its relatively low take-off speed. Curtiss proposed a side-by-side seating arrangement, power boost controls with an adjustable stabilizer, guns in the hull just above the normal load water line, and with provisions for incorporation of snow skis.

4. The comparative performance of the two airplanes is shown on enclosures (B), (C), (D), and (E), and the general arrangement on enclosure (F). The very high wing loading and thrust loading of the Curtiss design makes its altitude performance so poor as to be unacceptable, and makes its take-off performance marginal. The major advantages of the Curtiss design are its smaller size, weight, and cost and possibly better rough water performance. The Convair "Skate" has such a marked superiority in climb, altitude, and take-off that it is obviously the winner of this competition.

5. The only major design deficiency of the "Skate" found in the proposal was the cockpit arrangement. Convair proposed a single, off-center, bubble canopy over the pilot, with the radar operator seated lower and within the normal hull contour. The canopy as a whole, including the windshield was hinged at the aft end for access and for jettisoning. Vision forward for the radar operator and retention of a windshield during seat ejection are mandatory changes. More detailed studies on operational techniques are also considered necessary, although Convair did show possibilities of using modified submarines as fueling and rearming vessels. Although the airplane is capable of being hoisted aboard a seaplane tender, the hoisting sling attachment points are well aft of the cockpit. Normal mooring and anchoring provisions were not required by the specification,

6, As noted previously, the CNO has requested BuAer to initiate a seaplane fighter with fiscal '49 funds, and specifically approved the design requirements for the competition. Although neither of the two designs met the requirements, they were approached, and the performance is considered as high as could be expected at the present state of the art. The fiscal situation, however, is quite discouraging. Enclosure (F) shows an estimated cost including GPE of 17.7 million for two flight and one static test articles, based on a first flight date 29 months after go-ahead. The funds included in current planning programs for this project are as follows:

Fiscal '49

$295,000

Partial Phase I

Fiscal '50

$0


Fiscal '51

$1,000,000

Complete Phase I

Fiscal '52

$6,500,000

Partial Phase II

Fiscal '53

   $5,000,000   

Complete Phase II


$12,795,000


A million dollars of fiscal '54 funds, not yet planned, would be made available for flight test and correction of defects. Under the extremely slow development program permitted by planned funds, the estimated cost of 17.7 million will increase, further increasing the deficiency of 3.9 million already apparent. A reduction in the scope of the contract to not more than one flight and one test article will certainly be required. The net result of the foregoing is a five year development of an experimental airplane competitive in performance with carrier based airplanes now under production contract, and inferior to experimental carrier based airplanes now underway. No change in the allocation of funds in the fiscal programs are recommended at this time inasmuch as any reallocation of funds to retain the original scope of this project and to reduce the development period would have to be made by retarding the development of other experimental aircraft which have been assigned a higher priority.

7. However, with the existence of the CNO request to proceed, and with the fact that Consolidated-Vultee submitted the better proposal in the design competition, authority is requested to initiate negotiations leading to a partial Phase I contract with that manufacturer for development of a seaplane night fighter. The scope of the contract will be limited to further configuration studies and model testing until fiscal '51 at which time a reasonably timed development can be started. A suggested letter to the CNO advising him of the proposed action is attached.

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LIST OF REFERENCES

(a) BuAer Conf . ltr. Aer-AC-2, 03170 dtd. 27 April 1948 to CNO.
(b) CNO Conf. ltr. OP-55P-2B3/Jk, (SC)A1-1, Serial 064P55R dtd, 13 May 1948 to BuAer.
(c) BuAer Conf. ltr. Aer-AC-25, 08124 dtd. 1 Sept. 1948 to CNO.
(d) CNO Conf. ltr. OP-551C4/eb, (SC)A1-1, Doc. No. 229680, Ser. 017P551 dtd. 13 Sept. 1948 to BuAer.
(e) BuAer Conf. ltr. Aer-AC-25, 08972 dtd. 1 Oct. 1948.
(f) CVAC Conf. ltr. RLB:io, 6-98 dtd. 13 Jan. 1949.
(g) CVAC Conf. ltr. 11-1-2561, JPS:nw dtd. 28 Jan. 1949.
(h) CW Conf. ltr. FAM:mjt:218E dtd. 14 Jan. 1949.
(i) CW Conf. ltr. JWA:tc:135 dtd. 27 Jan. 1949.
(j) Douglas, S.M. Conf. ltr. G-123-1450 dtd. 19 Oct. 1948.
(k) Douglas, E. S. Conf. ltr. B-25-2603 dtd. 27 Oct. 1948.
(l) CVA Conf. ltr. SM-98 dtd. 22 Oct. 1948.
(m) Edo Conf. ltr. S-5106 dtd. 3 Nov. 1948.
(n) Bell Conf. ltr. JWR:ls dtd. 12 Nov. 1948.
(o) McDonnell Conf. ltr. JSM:bb, BA-01-1307 dtd. 17 Nov. 1948.
(p) Lockheed Conf. ltr. LAC/31693 dtd. 6 Dec. 1948.
(q) Fairchild Conf. ltr. CA-N-376 dtd. 17 Dec. 1948.
(r) Marine Aircraft Conf. ltr. LCM:MO'D dtd. 27 Dec. 1948.
(s) Boeing Conf. ltr. 751-1459 dtd. 10 Jan. 1949.
(t) NAA Conf. ltr. 48C13593 dtd. 29 Dec. 1948.
(u) GLM Conf. ltr. 3957, WGE:140 dtd. 13 Jan. 1949.
(v) Grumman Conf. ltr. #249-173E dtd. 8 Feb. 1949.

NOTE: Republic Aviation failed to submit bid or letter declining to bid.

ENCLOSURE (A)

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CONFIDENTIAL

PERFORMANCE SUMMARY

SEAPLANE VF



SPEC

CONVAIR

CURTISS

F7U-1

XF10F-1

Power Plant



2-XJ40-10

1-XJ40-10

2-XJ34-32

1-XJ40-8

Ratings







Military - SLS

Lb.


2 x 7920

7920

2 x 3500

7,310

Conbat - SLS

Lb.


2 x 11,750

11,750

2 x 4910

10,900

Crew


2

2

2

1

1

Radar



APQ-35

APQ-35

--

APS-25

T.O. Gross Wt.

Lb.


41,907

29,060

20,038

26,705

Fuel.

Lb.


12,590

9,277

5,822

9,600

Combat Rad. (F-5)

N.Mi.


375

310

290

575

Avr. Cr. Out Alt.

Ft.


40,000

23,300

39,050

38,750

Avr. Cr. In Alt.

Ft.


40,000

30,000

43,250

43,000

Combat Alt

Ft.


35,000

24,400

35,000

35,000

T.O. Time Sec.

Sec.


16

56.0

--

--

T.O. Speed Kn.

Kn.


99.5

154.5

99.3

111.0

Combat Weight

Lb.


36,871

25,350

17,707

22,465

Wing Loading

Psf


37.5

65.9

35.7

50

Vmax @ S.L.

Kn.


600

598

602

625

Vmax @ 35,000 ft.

Kn.

548

523

530

544

565

Vmax @ 35,000 ft

M. No.

0.95

0.917

0.919

0.945

0.98

R/C @ S.L

FPM


19,800

13,600

15,100

15,600

R/C @ 35,000 ft.

FPM


6,800

2,850

5,150

5,800

Combat Ceiling

Ft


53,300

42,800

47,000

50,000

Time to 35,000 ft

Min.


2.9

5.8

3.8

3.5

Ldg. Wt. (10% fuel)

Lb.


30,576

20,711

14,798

18,065

Vst power off

Kn.


80.4

124.0

83.0

92.0

Wing Area

Sq. Ft.


985

385

496

450

Span

Ft.


62.5

39.2

38.7

36.7

Length

Ft.


83.7

64.2

39.6

48.7

ENCLOSURE (B)

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