ARMY AIR FORCES
MATERIEL COMMAND
ENGINEERING DIVISION
MEMORANDUM REPORT ON

DATE: 22 May 1944

Subject: Mock-Up Inspection of Navy XTB2F-1 Airplane
Section: Technical Staff.
Serial No. ENG-50-1049

A. Purpose

1, To report results of mock-up inspection of the Navy XTB2F-1 airplane being built by the Grumman Aircraft Engineering Corporation, Bethpage, L.I., N.Y.

B. Factual Data

2. Personnel comprising the Mock-up Committee are as follows:

3. In addition to the Above, Grumman representatives were as follows:

4. The mock-up of this airplane was very complete and wherever possible the actual item was installed.

5. Grumman Representatives did an excellent job of keeping the mock-up conference running smoothly and were very efficient in making recommended mock-up changes over night in time for the next day's inspection.

6. Navy personnel were very courteous to the Materiel Command representative and willingly furnished engineering data and information in answer to all questions asked.

7. This airplane project is a most ambitious one, for the Navy and for Grumman, who have never attempted an airplane of this large size before.

It is an outgrowth of experience gained from the Grumman TBF with an effort to increase range, bomb load and effectiveness of all armament components.

8. The XTB2F-1 is to be used for horizontal, glide (up to 50°), masthead and torpedo bombing, mine laying, sub and long rang patrol.

9. A more detailed description of this airplane is contained in Exhibit "A"

C. Conclusions.

1. The performance of the subject airplane falls short of the minimum performance now desired by Army Air Forces although it may prove to be remarkable as a carrier based bomber.

2. Inasmuch as Grumman expects this airplane to see combat in about two years, airplanes that the AAF now has under development will be in production then and will far out perform the subject airplane in all of its functions.

D. Recommendations

1. It is recommended that the experimental progress of the subject airplane be followed and flight test performance be obtained for comparison with AAF aircraft.

Prepared by
G. D. Colchagoff. Capt. A.C.

Approved by
H. Z. Bogert. Colonel, A.C.
Chief. Tech.Staff

Approved by
F. O. CARROLL. Brig. Gen. U.S.A.
Chief Engineering Division

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Distribution:
      Bureau of Aeronautics
      Bureau of Aeronautics Gen Rep.
      Materiel Command Liaison Office at the Bu. of Aero.
      AC/AS, MM&D, Devel. Engr. Br. (3)
      Production Eng. Sec.
      Bombardment Bu. Tech. Staff.

Eng. Div. Memo. Rep. ENG-50-1049
22 May 1944

EXHIBIT "A"

1. General

A. The Bureau of Aeronautics has contracted with the Grumman Aircraft Engineering Corporation, Bethpage, Long Island, New York, for the construction of two (2) XTB2F-1 experimental airplanes, the first of which should be ready for initial flight late in 1945. Production models are expected to be started in the summer of 1945.

b. The XTB2F-1 Airplane is a twin-engine, 4-place torpedo-bomber landplane for use ashore and aboard aircraft carriers as a torpedo plane, glide or skip bomber, or as a scout airplane.

e. The airplane shall take off from the deck of an aircraft carrier of the CVB Type with or without the aid of a catapult and land on a carrier deck in an arresting gear or on an ordinary landing field.

2. Description

a. The XTB2F-1 is a conventional high wing airplane somewhat similar to the B-26 except that the requirement that this airplane be carrier based has resulted in short thick wings and fuselage.

b. The wing span is 74 feet, chord is 12.5 feet at the root and the area is 777 square feet. The wing folds back and outboard so that the span is 36 feet. The hydraulically operated flaps are of the fixed hinge slotted type. The airfoil is of the NACA 23017 at the root and NACA 23011 at the tip. This airplane is designed for a 4 G yield and a 6 G ultimate.

e. The empennage has conventional symmetrical tail surfaces. The height of the vertical stabilizer is normally 19 feet so in order to have proper clearance for stowage below decks in the carrier hangers, the nose wheel strut will be extended by means of a hydraulic accumulator to lower the tail two feet.

d. The landing gear is of the tricycle type except that there are dual nose wheels on the nose wheel strut. The main wheel thread is 23 feet.

e. The fuselage window arrangement for the pilot is similar to the C-46 and has excellent visibility, the mock-up committee recommended even more window panels overhead. The cockpit arrangement is identical with the Navy single pilot type now used in service except that a wheel type control will be used and there will be a Pioneer type A-10 Auto-Pilot.

f. The normal crew will consist of four members; pilot, radio and radar operator who will sit next to the pilot, and top turret and bottom turret operators. Each will have individual para-life rafts.

g. A passage way over the bomb bay will connect the fore and aft decks. This aft deck will contain only the top and bottom turrets.

3. Power Plant

a. The XTB2F-1 Airplane is powered by two Pratt & Whitney Model R-2800-22 single stage two-speed, right hand rotation engines geared 0.4-5:1. There are no provisions for War Emergency Power. The Military Power for each engine is 2100 BHP at 2800 RPM.

b. The engine ring cowl, cowl flap, dishpan cowl and exhaust system are identical to that of the F7F-4. Both right and left engines and their mounts are interchangeable.

c. The propeller to be used in conjunction with this engine is the 3-blade, Curtiss electric 14.'-0" with No. 830 blades.

4. Armament

a. The XTB2F-1 Airplane will have six forward firing fixed .50 caliber machine guns and two turrets.

b. Two .50 caliber guns will be located in the left side of the fuselage under the pilot compartment. Each gun will have 400 rounds of ammunition.

c. Four .50 caliber guns will be located in the wing, two on each side of the fuselage, with an alternate installation of either 20 millimeter or .60 caliber guns in place of the .50 caliber guns on the same mountings. The .50 caliber guns will have 400 rounds of ammunition each while the 20 millimeter and the .60 caliber guns will have 200 and 120 rounds of ammunition respectively per gun. All three installations would use the same size ammunition box.

d. There is an Emerson Modified Dumbo upper turret over the aft end of the bomb bay with two .50 caliber machine guns and 400 rounds per gun.

e. A standard Sperry A-13-A inhabited retractable lower turret behind the bomb bay contains two .50 caliber machine guns with 400 rounds each.

f. There will be provisions for both a 75 millimeter cannon and a Mark 15 optical bombsight on the right side of the pilot's deck. It is intended that only one of the two will be installed at any one time. Inasmuch as it is felt that the airplane will seldom be used for high altitude bombing, the 75 millimeter cannon will be the common installation.

g. The optical bombsight is being specified, but it is expected that a radar type bombsight will be used when it is available.

h. Pilot will fire the cannon and guide on radar operated cross hairs. The pilot's sighting will be done by a torpedo director radar type gunsight. For this purpose a standard Mark 8 with a tilting reflector will be used in conjunction with the 75 millimeter cannon Radar Ranging device.

i. The fourth crew member will sit next to the pilot to assist him on take offs and landings and operate the Radar Ranging device for the 75 millimeter cannon or the optical and eventually the radar bombsight, and also the other radio equipment.

j. In low level attacks the 75 millimeter cannon will be manually loaded by the ball turret operator with 12 rounds of ready ammunition.

k. The cone of fire of the flexible guns is such that upper turret fires 10° below the horizon on all sides except for the airplane's structure. The lower turret fires 8-1/2° up all around except for the fuselage structure. At V maximum the upper turret fires straight ahead while the lower turret fires 1-1/2° below the horizon.

l. In lieu of a drift sight both the optical bombsight and the lower turret with a built-in azimuth scale will be used.

m. locket provisions will be made several months prior to delivery of the first production airplane.

n. There will be a torpedo camera (F-46) and a gun camera, for the fixed guns in the nose. The upper and lower turrets will both have gun cameras.

o. Passive protection against .30 caliber gunfire is provided for the pilot, crew, oil tanks, and oil coolers. Provisions will be made for protection against .50 caliber gunfire.

5. Bomb Provisions

a. The XTB2F-1 airplane has an excellent bomb bay arrangement. The mock-up was very complete and all the various bomb, mine, and torpedo loads were simulated by full scale models. The bomb bay will normally have 20 shackle stations, 9 on each side and 2 in the roof on the center line. For 100 pound bombs, there will be an alternate installation 36 shackle stations by the addition of 3 complete center bay sections.

b. The shackles will be placed so that there is no possibility of a bomb, torpedo or mine striking any part of the airplane structure after release during horizontal bombing or during release in glide bombing angles up to 50 degrees.

c. The bomb and mine loads to be carried are as follows:

1	4000# Class bomb,	or	24	100# fragmentation bomb clusters, or
4	2000# Class bombs,	or	4	650# Depth Bombs, or
4	1600# Class Bombs,	or	10	350# Depth Bombs, or
4	1000# Class Bombs,	or	10	325# Depth Bombs, or
10	500# Class Bombs,	or	2	2000# Class Mines, or
10	500# Incendiary Bomb Clusters	or	4	1000# Class Mines.
36	100# Class bombs,	or

Either one or two 2084# torpedoes can be carried.

d. The contractor stated that it is possible to carry 10 - 1600# bombs, It will be possible to carry one 2000# class bomb in place of each of the two external wing tanks.

6. Weight

a. The XTB2F-1 Airplane is expected to fly normally at approximately 38,000#. This is as a torpedo bomber. This, and the other gross weight con ditions of the airplane, is expected to be increased as a result of the recommendations made by the Mock-Up Committee.

7. Fuel

a. The XTB2F-1 Airplane fuel tanks have the following capacities;

	Protection	Service Capacity
Main Wing tanks	Self-sealing cell	960 gallons
Two auxiliary droppable wing tanks	None	600 gallons
	Total fuel capacity	1,560 gallons

8. Range and Radius of Action

a. The range of the XTB2F-1 Airplane with 1,560 gallons of fuel and 4 - 2000# bombs carried one half of the distance is 3050 miles.

b. Radius of Action estimated for the XTB2F-1 Airplane with 960 gallons of internal fuel.

	Fuel	Distance
Warm-Up - 20 minutes	25.2	0
Take-off - 1 minute	11.0	0
Rendezvous - 10 minutes. 60% normal power	28.8	0
Climb to 15,000 ft. at 60% normal	110.0	89
Cruise out at 15,000 ft. at 60% normal	252.5	304
Combat - 5 minutes mil, 10 minutes normal	133.2	0
Cruise back at 60% normal power	331.4	393
Reserve - hour	67.9	0
	960	786

Radius of Action = 393 nautical miles or 452 miles.

Radius of Action estimated for the XTB2F-1 Airplane with 960 gallons of internal and 600 gallons of external fuel.

		Fuel	Distance
Warm Up - 20 minutes		25.2	0
Take-off - 1 minute		11.0	0
Rendezvous - 10 min. 60% normal power		28.8	0
Climb to 15,000 feet at 60% normal		126.5	102
Cruise out at 15.000 feet at 60% normal		408.5	443
Drop external wing tanks	Total	600.0	545
Cruise out continued		150.4	177
Combat - 5 min. mil., 10 minutes normal		133.2	0
Cruise back at 60% normal		608.5	722
Reserve - 1 hour		67.9	0
	Total	1560	1444

Radius of Action - 722 nautical miles or 833 miles.

9. Performance

a. The following performance is estimated for a gross weight of 37,027 pounds and 960 gallons fuel:

High Speed at seal level, mil power (MPH).	309
High Speed at airplane crit. alt. (MPH)	331
Stalling Speed at sea level, full load, without power (MPH)	94.3
Rate of Climb at sea level rail, power (ft./min.)	2,230
Time to Climb - to 10.000 ft. alt. (Min)	5.5
to 20,000 ft. alt. (min)	13.3
Service Altitude (feet)	27,380
Endurance at 5000 ft. - at 60% high speed (hrs)	11.68
Maximum (hrs)	13.50
Maximum Range at 5000 ft. Alt. - with torpedoes or bombs carried 1/2 distance (miles)	2,020
Average Speed for maximum range (MPH)	170
Take-off distance - in calm (feet)	1,057

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Aer-E-17-BTE
VTB2F1/F1-1, C16474

Confi - 16 Jun 1944

From: Chief, BuAer
To: BAR, Bethpage, L.I., New York
Subj: Model XTB2F-1 Airplane - Mock-Up Board Report
Encl.( (A) Two (2) copies of Mock-up Board Report. (HW)

1. Subject report is hereby forwarded as Enclosure (A). This report is for record purposes only as this project is being cancelled.

W. W. HOLLISTER
Comdr. U.S.N.