F7F-3 with APS-6 radar?

[Steve Hnz]

I'm not finding anything on it yet but wonder if that small radar shown in the cutaway diagram was an early version of the AN/APG-30 fire control radar used in the F-86E/F later on to great effect, or a figment of the diagram drawers imagination.

 

[EwenS]

I'm not finding anything on it yet but wonder if that small radar shown in the cutaway diagram was an early version of the AN/APG-30 fire control radar used in the F-86E/F later on to great effect, or a figment of the diagram drawers imagination.

You mean the AN/APG-30 attached to the A-1C(M) gunsight? One letter makes a big difference. A fitting on the F7F seems several years too early though.

The A-1C(M) gunsight: a case study of technological innovation in the United States Air Force. - Free Online Library

Free Online Library: The A-1C(M) gunsight: a case study of technological innovation in the United States Air Force. by "Air Power History"; Military and naval science Fighter planes Equipment and supplies Fire control (Gunnery) Design and construction Innovations Fire control systems (Gunnery)...

www.thefreelibrary.com

The AN/APS-30 was a surface search / targeting radar fitted to the Grumman AF-2S Guardian (the "killer" version of the "Hunter-killer" pairing), in an underwing pod.

 

[Steve Hnz]

You mean the AN/APG-30 attached to the A-1C(M) gunsight? One letter makes a big difference.

Oops, yeah, you right of course, fixed it. I'm leaning towards artistic licence imagination on this one.

 

[Wurger]

Actually it looks like the AN/APS 6 antenna ... that fitted the F7F-1N or 2N "nose"guite nice according to the picture below.

the source: ( Northrop Grumman History Center ) via what planes will get radar? Radar questions?

 

[Steve Hnz]

That WT article does make it sound feasible.

 

[GreenKnight121]

The information I have does indeed state that the initial run of single-seat F7Fs DID have the APS-6 radar in the NORMAL nose... it was the larger APS-19 that required the longer/different-shaped nose without guns!

The first of 500 planned F7F-1s flew in April 1944. Initial production would be night fighters with APS-6 radar in the nose and Pratt and Whitney 2,100 hp R-2800-22 engines. The third was modified to the two-place XF7F-2 with a radar operator's cockpit behind the pilot. Deemed a more effective night fighter configuration, all airplanes after the first 34 would be F7F-2s.

Supported by successful test operations of an F7F-1 on board Shangri-La (CV 38) in November 1944, -2 production would end at 100 with subsequent F7F-3s having a strengthened airframe and an updated R-2800- 34W engine. By this time, the -1s and -2s had been redesignated -1Ns and -2Ns as night fighters.

Initial -3s were produced as single-seat fighters, with some having photo installations added as -3Ps, and others a more effective radar as two-place -3Ns. The Naval Aircraft Modification Unit, Johnsville, Pa., prototyped the -3P; Grumman prototyped the two-place -3N with nose guns removed and a larger "drooped nose" for the radar.

To expedite production of the different -3 models, all were built single-place with some variations to accommodate the changes for the intended final model. The Ps and Ns were accepted at Grumman and ferried to the Navy Lockheed Service Center in Van Nuys, Calif., where they were completed for final delivery to operating units. A larger vertical fin was tested and finally incorporated in production, as well as backfitted in earlier -3 models.

In April 1946 -3N production was cut back, after which 12 -4Ns with extensive changes for carrier operating strength would be built. Also included was a new APS-19 radar in a stream-lined nose, tested on a -3N as the XF7F-4N, and retrofitted to the -3Ns.

So there were a number of single and two seat F7F-1 & two seat F7F-2s built with the APS-6 in a normal gun-equipped nose (the cutaway does show an APS-6 equipped single-seat -3), and both single seat [strike]APS-6 equipped F7F-3s with gun-equipped noses[/strike] single-seat F7F-3s with basic day-fighter equipment only and two seat F7F-3Ns with the [strike]APS-19[/strike] SCR-720 radar in a longer gunless nose. {edit: there were also 12 F7F-4Ns with the APS-19 in a more streamlined nose.}

Note that the camera equipped F7F-3Ps and the radar equipped F7F-3N were converted from single-seat F7F-3s in a pre-planned post-assembly modification scheme to allow uninterrupted airframe production.

 

[GreenKnight121]

Here is a somewhat clearer version of the cutaway, with the text more-readable. Note that it shows the machine guns in the lower nose along with the APS-6 radar.
{edit: It seems that the F7F-3s that remained single-seat fighters did not actually have the APS-6 fitted, so this is in error.}

 

[Steve Hnz]

Thanks for that Greenknight, that does straighten things out somewhat & helps with some things I was reading but not being given the whole story.

 

[Hoggardhigh]

The information I have does indeed state that the initial run of single-seat F7Fs DID have the APS-6 radar in the NORMAL nose... it was the larger APS-19 that required the longer/different-shaped nose without guns!



So there were a number of single and two seat F7F-1 & two seat F7F-2s built with the APS-6 in a normal gun-equipped nose (the cutaway does show an APS-6 equipped single-seat -1), and both single seat APS-6 equipped F7F-3s with gun-equipped noses and two seat F7F-3Ns with the APS-19 in a longer gunless nose.

Note that the camera equipped F7F-3Ps and the radar equipped F7F-3N were converted from single-seat F7F-3s in a pre-planned post-assembly modification scheme to allow uninterrupted airframe production.

IIRC, your original version of post #26 states that the F7F-3 single seaters were built without radar, but seems to have been edited to state that they did indeed retain the APS-6 of the F7F-1/-2 models.

 

[Elvis]

Looking at that diagram again, there is nothing on it to indicate exactly what model of F7F it is supposed to represent. It might even be some kind of composite. Note that while a radar set is shown in the nose (type unspecified but probably an AN/APS-6 from the nose shape) there is no armament in the nose. And it represents a single seater.

The F7F-1 and -3 were single seat, day fighter models that had 4x0.5" in a nose that lacked radar.

The F7F-2 was a two seater intended as a night fighter with AN/APS-6 radar in the nose. Most were built as F7F-2N night fighters, BUT some were built as F7F-2 but still retained the second seat looking at the photos. The -2N had the radar but no nose armament. The -2 had the nose armament and no radar. But the -2 also had provision for an 80 gallon reserve tank in the rear cockpit space, a feature shared with the following F7F-3 day fighter.

Returning to the diagram, the line of the upper fuselage resembles that of the F7F-2/-2N and F7F-3/-3N and not the F7F-1. And there is a "Reserve fuel tank" in the area of the rear cockpit (item 83) which would indicate either a -2 or a -3. The description is not too clear due to the quality of the image so I can't read the size, but that is what I think it says.

It can't be a two seat F7F-3N as it had a different radar and nose shape.

So, at the moment, I can find nothing to suggest that the F7F-3 got the AN/APS-6 radar. I think the diagram is a composite of features that appear on the F7F-2 and F7F-2N.

Re: Reserve fuel tank capacity.
It appears that reads "185 gal./700 L."
If you Google the conversion from Litres to U.S. Gallons, 700 L = 184.92 gallons.
80 U.S. Gallons = 302.833 Litres, so if the tank's capacity was 80 gallons, the conversion would likely read "300 L.".
Speculation on my part, but if you're quoting a credible source for the 80 gallon capacity of the reserve tank, then it could be a misprint on that cutaway, too.

 

[Hoggardhigh]

If you read the attached document, there is no mention of an APS-6 installation in the (single-seat) F7F-3.

Could that mean the APS-6 was retained in the F7F-3 but left inoperative? If so, that would mean the basic F7F-3 could be fitted with the radar operator's position of the F7F-2N if desired.

 

[EwenS]

Well the diagram above has one inaccuracy compared to the official BuAer document.

Item 83 to which I referred earlier was NOT a single 185gal tank. It WAS 2 tanks. A lower one of 110gal and an upper one of 80gal. The latter is the one is the Reserve tank that my sources state could be fitted in place of the second cockpit on the F7F-2.

 

[fubar57]

 

[Elvis]

Well the diagram above has one inaccuracy compared to the official BuAer document.

Item 83 to which I referred earlier was NOT a single 185gal tank. It WAS 2 tanks. A lower one of 110gal and an upper one of 80gal. The latter is the one is the Reserve tank that my sources state could be fitted in place of the second cockpit on the F7F-2.

So you're saying item 83 in the cutaway was a typo, or were they just combining the capacity of both tanks? (the combination theory may explain Fubar's chart, too)

 

[Hoggardhigh]

View attachment 694602​

What are you saying with the attached table?

 

[GreenKnight121]

If you read the attached document, there is no mention of an APS-6 installation in the (single-seat) F7F-3.

Could that mean the APS-6 was retained in the F7F-3 but left inoperative? If so, that would mean the basic F7F-3 could be fitted with the radar operator's position of the F7F-2N if desired.

According to the table posted by fubar57, it seems the basic F7F-3 did NOT have any radar... I had edited my post because re-reading the text I had seemed to imply that they still did have it.

I have now re-edited it.

 

[EwenS]

So you're saying item 83 in the cutaway was a typo, or were they just combining the capacity of both tanks? (the combination theory may explain Fubar's chart, too)

However you choose to look at it the statement on the diagram is incorrect. That casts doubt on its accuracy. And where one error exists there may well be others, like the inclusion of the radar.

 

[Elvis]

However you choose to look at it the statement on the diagram is incorrect. That casts doubt on its accuracy. And where one error exists there may well be others, like the inclusion of the radar.

Very true.
Sometimes, you have to question the source.

 

[ThomasP]

I believe that when both tanks (1x80+1x105) were fitted they were plumbed as a single reserve tank of 185 USgal as far as the fuel system was concerned (ie there was only 1 fueling point and 1 fuel gage for the combined tankage). So the diagram is correct as far as the fuel system goes?

 

[Avn-Tech]

This is a photo of an F7F-3 nose. Looking at it there is no radar in the nose. This is original from the 1950's.

There is probably room to put a radar in the nose, but there is no evidence of a radar ever being installed in the nose.