# Corsair as Dive Bomber?



## Freebird (Nov 20, 2016)

I saw this mentioned on a different forum - the Corsair's landing gear extended as dive brakes?
Was this really a viable option?
And was this intended by design, or battlefield improvisation?
Was it commonly done?

F4U using gear as dive brakes


----------



## bobbysocks (Nov 20, 2016)

I have heard of fighter pilots start to drop gear for various reasons... but you would have to be very careful doing this as if you exceed V LE then you could do a lot of damage to your plane.


----------



## GrauGeist (Nov 20, 2016)

In the F4U-4 pilot's manual AN 01-45HB-1, on pages 13 - 14, section 4, is titled:
(4) DIVE BRAKE CONTROL - (a) The dive brake control is located on the left hand shelf. To extend the dive brake, move the landing gear control into the "DOWN" position of the dive brake slot; this extends the main landing gear only, leaving the tail wheel retracted. To retract the dive brake, move the control to "UP".

It refers the reader to "figure 14", which is on page 17, showing the airframe flaps and landing gear hydraulic system, including the dive brake system and controls (with control panel inset).


----------



## wuzak (Nov 20, 2016)

At what angle could the Corsair dive with the dive brake control?


----------



## Freebird (Nov 20, 2016)

GrauGeist said:


> In the F4U-4 pilot's manual AN 01-45HB-1, on pages 13 - 14, section 4, is titled:
> (4) DIVE BRAKE CONTROL - (a) The dive brake control is located on the left hand shelf. To extend the dive brake, move the landing gear control into the "DOWN" position of the dive brake slot; this extends the main landing gear only, leaving the tail wheel retracted. To retract the dive brake, move the control to "UP".
> 
> It refers the reader to "figure 14", which is on page 17, showing the airframe flaps and landing gear hydraulic system, including the dive brake system and controls (with control panel inset).


So this was a purpose designed system then?

Was this the WWII manual? Or later?


----------



## GrauGeist (Nov 20, 2016)

Yes, it was a purpose-built feature and the initial date of issue for this manual was 1 October 1944 with later revisions. 

I'll see about getting you some page views when I'm on the computer and not this ipad.


----------



## Shortround6 (Nov 20, 2016)

The Manual for the F4U-1, FG-1, F3A-1 (Goodyear and Brewster built versions) mentions the airbrake and states the airbrake will not fully extend and lock at speeds over over 260kts and should not be retracted at speeds over 350knts. 
Aside from being mentioned in the dive checklist and the above restrictions the manual has a very similar passage to that given by GrauGeist for the F4U-4. 

The pilot's manuals are about basic flying and restrictions for a type of aircraft. Actual tactics/procedures for different operations would be in a different manual/publication. For example there are NO suggestions/hints/tips for air to air combat in fighter manuals.


----------



## Greyman (Nov 21, 2016)

For what it's worth - British Pilot's Notes:

(i) _Maximum speeds_
Lowering undercarriage (normal) .. 200 knots IAS

(iii) _Dive bombing_
Maximum speed (undercarriage up) .. 375 knots IAS
Maximum speed for lowering undercarriage (dive brakes) .. 250 knots IAS
Maximum speed undercarriage down .. 350 knots IAS

(vi) _Bombs_
Maximum speed when carrying bombs .. 375 knots IAS
Maximum speed when releasing bombs .. 300 knots IAS
Accelerating and arresting are permissible, but the angle of dive when releasing bombs must not exceed 60 degrees. Salvo release is not permitted.

Reactions: Like Like:
1 | Informative Informative:
2 | Like List reactions


----------



## drgondog (Nov 21, 2016)

Often wrong but rarely uncertain - I would doubt that any analysis of 'performance considerations of lowered landing gear' was considered in preliminary design. I suspect that the limits were brought to screeching attention when a wing failure occurred due to lowering gear at high speed.

This example specifically occurred due to P-51B wing failures when the wheel/gear uplock failed in high G pullouts, the gear crashed through the wheel cover, caught a 400+kts blast of dynamic pressure and yanked a wing off.

Reactions: Informative Informative:
2 | Like List reactions


----------



## michaelmaltby (Nov 21, 2016)

The Saab B-17 was engineered around the lowered landing gear strategy

Reactions: Informative Informative:
1 | Like List reactions


----------



## Shortround6 (Nov 21, 2016)

The feature of using the landing gear on the F4U as a dive brake may or may not have been in the initial design. It may have been added among the 800 or so modifications between the prototype and the first production models. The F4U being the first Navy plane to be exempt from the terminal velocity dive test. The plane/s the Navy purchased (at least prototypes) had to make a dive of such length/duration that the plane reached a speed at which it would simply go no faster due to drag. With the Corsair the initial dives took up so much altitude and required such severe pullouts (and were running into comprehensibility problems) that the Navy canceled the requirement. 
Perhaps the lowered landing gear air brake was added at this time help restrict dive speeds in general. The idea that the landing gear and doors would act as a dive brake for dive bombing in a way similar to true dive bombers takes a bit of swallowing.





Dive brakes on SBD




SBC Helldiver dive brakes.





The F4U landing gear would certainly help but I doubt it could allow dives of thousands of feet near 60 degrees.

Reactions: Like Like:
1 | Informative Informative:
1 | Like List reactions


----------



## RCAFson (Nov 21, 2016)

Greyman said:


> For what it's worth - British Pilot's Notes:
> 
> Accelerating and arresting are permissible, but the angle of dive when releasing bombs must not exceed 60 degrees. Salvo release is not permitted.



This what my F4U manual AN 01-45HA-1 states:


> DIVE BRAKE CONTROL-The dive brake con-
> trol may be operated at any speed within the normal air-
> plane restrictions in Model F4U-l airplanes number 82278
> and subsequent and Model FG-l airplanes number 76196
> ...



I suspect that the 60 deg drop limitation was due to the fact that all bombs were carried very near the centre-line and consequently they could contact the prop at very steep dive angles. However, I can't find anything about that in the above manual.


----------



## stona (Nov 21, 2016)

RCAFson said:


> T
> 
> I suspect that the 60 deg drop limitation was due to the fact that all bombs were carried very near the centre-line and consequently they could contact the prop at very steep dive angles. However, I can't find anything about that in the above manual.



Because they wouldn't hit the propeller. Both the the USAAF and the USN established this independently, the USAAF using 'vertical' dives with a P-47. I'd have to look up which aircraft the USN used, but the results were discussed at the Patuxent River fighter conference and I posted the relevant section in another thread sometime ago.
'Vertical' dives, at least in USAAF parlance, seem to refer to any dive at an angle of 70 degrees or more...not necessarily literally vertical.
Cheers
Steve

Reactions: Informative Informative:
1 | Like List reactions


----------



## tomo pauk (Nov 21, 2016)

Shortround6 said:


> ...
> (and were running into *comprehensibility* problems)
> ...



Happened to me many times

Reactions: Funny Funny:
1 | Like List reactions


----------



## stona (Nov 21, 2016)

I have found the relevant page in the 8th AF history.






Cheers

Steve

Reactions: Like Like:
1 | Informative Informative:
3 | Like List reactions


----------



## RCAFson (Nov 21, 2016)

stona said:


> Because they wouldn't hit the propeller. Both the the USAAF and the USN established this independently, the USAAF using 'vertical' dives with a P-47. I'd have to look up which aircraft the USN used, but the results were discussed at the Patuxent River fighter conference and I posted the relevant section in another thread sometime ago.
> 'Vertical' dives, at least in USAAF parlance, seem to refer to any dive at an angle of 70 degrees or more...not necessarily literally vertical.
> Cheers
> Steve



I'd be curious to see what the USN tests showed. 

You can see here that the P-47 and F4U have very different centre line prop/bomb geometry:
File:Republic P-47N 3-side drawings.PNG - Wikipedia
https://upload.wikimedia.org/wikipe...air_Standard_Aircraft_Characterisics_1953.PNG

note how the P-47 prop circle just covers the DT with the prop tip while that of the F4U covers the DT at the mid point of the prop.


----------



## stona (Nov 21, 2016)

RCAFson said:


> I'd be curious to see what the USN tests showed..



Essentially that the aircraft separates from and accelerates away from the bomb.

pp156/7 of my edition of the 'Report of Joint Fighter Conference'.

Commander Monroe:
_"Our fighters are authorized to dive up to 85 degrees. Of course they have no displacing gear. Careful investigation down here shows absolutely no danger of the bomb hitting the propeller. At least the airplane and the bomb keep their relative pressures fore and aft, and the bomb drops away from the airplane, which was a great relief to everybody."_

This agrees broadly with what the USAAF had also discovered.

Whether 'our fighters' includes the F4U I can't say for sure. The date of the conference was 16th - 23rd October 1944, so it had been in service for some time.

In the interest of balance, I have read somewhere (can't remember where) that Douglas were developing a bomb displacement system powered by a cartridge, and an automatic pull out system, both designed to throw a bomb clear of an aircraft propeller. I don't know which aircraft were involved, and as far as I know such a system never saw service. I would happily be corrected, US aircraft are not really my forte 

Cheers

Steve


----------



## Milosh (Nov 21, 2016)

edit ; wrong thread
Thanks GG for the fix

Reactions: Like Like:
1 | Like List reactions


----------



## GrauGeist (Nov 21, 2016)

Somewhere after the "steady 400-500 boat" portion of your post, the strike command was used, this is an S contained in brackets [ S ]

Go into the editor, select "plain text editor" (little wrench in the upper right of the tool bar) and look for that command in your post. You can't see the BBS commands in rich text.


----------



## Dana Bell (Nov 23, 2016)

Hi Guys,

The landing gear/speed brake combination was part of the initial design of the Corsair, derived from the same feature on the Vindicator. Vought developed separate speed brakes for the SB2U, but the Navy preferred to save the weight and use the landing gear for the purpose. Remember that early Corsairs carried no centerline bomb racks, using only two outboard wing racks for light bombs (part of the Navy's demand that all fighters be capable of suppressing shipboard anti-aircraft fire).

Cheers,


Dana

Reactions: Informative Informative:
1 | Like List reactions


----------



## tomo pauk (Nov 23, 2016)

The early Corsairs have had no racks what so ever. The 1st time the rack was installed, it was under the centreline. Later models got two racks under the inner wing portion, the centreline rack being removed. Post war the centreline rack was installed.
The prototype Corsair have had bomb bays in the wings for small anti-aircraft bombs.


----------



## stona (Nov 23, 2016)

tomo pauk said:


> The 1st time the rack was installed, it was under the centreline.



Was that for a bomb or just a drop tank?
I've seen a picture of a rather crude bodge job of a centreline bomb rack on a USMC aircraft, certainly with no kind of displacement gear, but just wondered if it was ever an official fitting. As I said, US aircraft are not really my thing 

Cheers

Steve


----------



## tomo pauk (Nov 23, 2016)

There was no fancy dispalcement gear installed, and it indeed looked like an improvisation of the bomb rack on the F4U-1A (picture of a model).
The later F4U-1D introduced 2 racks, where the bombs were neatly attached.


----------



## Dana Bell (Nov 24, 2016)

tomo pauk said:


> The early Corsairs have had no racks what so ever. The 1st time the rack was installed, it was under the centreline. Later models got two racks under the inner wing portion, the centreline rack being removed. Post war the centreline rack was installed.
> The prototype Corsair have had bomb bays in the wings for small anti-aircraft bombs.




Hi Tomo,

Thanks for the correction, but you are wrong about that. The very first 575 production F4U-1s and the first 1247 FG-1s carried a removable Mark 41-2 bomb rack under each wing, just outboard of the wing guns. The rack was used in testing and training, but I've never heard of its combat use.

Records of the XF4U-1 have been tough to track down, but the few documents I've found in the Archives suggest that the internal bomb racks were also intended for anti-aircraft suppression - against shipboard and ground AA guns - rather than the oft listed plan to attack other aircraft by bombing them in flight. This last point is speculation on my part - while the records suggest this, I've never found a definitive explanation of those internal bomb racks.

You might enjoy my two books on early Corsairs:

Amazon product
_View: https://www.amazon.com/Aircraft-Pictorial-No-F4U-1-Corsair/dp/0985714972/ref=sr_1_9?s=books&ie=UTF8&qid=1479992344&sr=1-9&keywords=f4u+corsair_


and 

Amazon product
_View: https://www.amazon.com/Aircraft-Pictorial-No-F4U-1-Corsair/dp/0985714999/ref=sr_1_11?s=books&ie=UTF8&qid=1479992344&sr=1-11&keywords=f4u+corsair_


Cheers,


Dana


----------



## tomo pauk (Nov 24, 2016)

Thank you for the tips.
Hopefully you could post a picture or two where early Corsairs have outboard wing racks installed, but no inboard rack(s)?


----------



## Dana Bell (Nov 24, 2016)

Hi Tomo,

Try this one:

f4u corsair bomb rack - Google Search

That's a practice bomblet dispenser mounted on the rack. There are far better images in the books...

Cheers,


Dana

Reactions: Like Like:
1 | Like List reactions


----------



## tomo pauk (Nov 24, 2016)

Thank you for pointing me on the right direction, Dana. I stand corrected 
The F4U-1 detailed specification indeed shows two bombs outboard the undercarriage, listing them as 2 x 100 lbs. link
Data sheet for the F4U-1, payload includes a torpedo(!): link

Reactions: Like Like:
1 | Like List reactions


----------



## Timppa (Nov 25, 2016)

It was very difficult for the pilots to see the dive angle.


----------



## Timppa (Nov 25, 2016)

stona said:


> Because they wouldn't hit the propeller. Both the the USAAF and the USN established this independently, the USAAF using 'vertical' dives with a P-47. I'd have to look up which aircraft the USN used, but the results were discussed at the Patuxent River fighter conference and I posted the relevant section in another thread sometime ago.
> 'Vertical' dives, at least in USAAF parlance, seem to refer to any dive at an angle of 70 degrees or more...not necessarily literally vertical.
> Cheers
> Steve



The bomb definetely accelerates faster than the aircraft, so the pilot did NOT have much time to pull away, in real 90 degree dive..


----------



## stona (Nov 25, 2016)

Timppa said:


> The bomb definetely accelerates faster than the aircraft, .



Only the force of gravity could act to accelerate the bomb. Whether it will accelerate the bomb or whether the bomb will in fact decelerate once released depends on the forces opposing gravity, principally the drag of the bomb.
I have no idea how that works out for different scenarios, but knowing the terminal velocity at typical altitudes for the bomb(s) would be a good starting point. Of course it also depends on what the aircraft is doing, since it is the relative motion between the two which matters.
I know Douglas' concern was for 'flapped', presumably meaning 'braked', aircraft which, being designed as dive bombers, might not be accelerating in the dive at all, but be diving at a constant speed.
The automatic pull out system being discussed would start to move the aircraft away from the course of the bomb immediately after separation.
Cheers
Steve


----------



## Timppa (Nov 26, 2016)

stona said:


> Only the force of gravity could act to accelerate the bomb. Whether it will accelerate the bomb or whether the bomb will in fact decelerate once released depends on the forces opposing gravity, principally the drag of the bomb.
> I have no idea how that works out for different scenarios, but knowing the terminal velocity at typical altitudes for the bomb(s) would be a good starting point.
> Steve



OK. True vertical dive bomb scenario:
- Typical terminal velocities of the bombs I have have seen quoted is about 600mph.
- F4U limit speed with its gear extended is 250-260knots, or 300mph.
- Half the speed means quarter of the drag force (ignoring compressibility)
- That means bomb acceleration relative to the aircraft is initially 3/4 of "g" .
- The distance from the propeller to the bomb is about 2 metres.
- Bomb will hit the propeller in less than one second after release.

So, IMO, true vertical dive is not possible.
There was a reason for bomb skip arms of dedicated dive bombers, like SBD or Ju-87.


----------



## XBe02Drvr (Nov 26, 2016)

Timppa said:


> OK. True vertical dive bomb scenario:
> - Typical terminal velocities of the bombs I have have seen quoted is about 600mph.
> - F4U limit speed with its gear extended is 250-260knots, or 300mph.



F4U limit speed with its gear extended IN DIVE BRAKE MODE is 350 knots INDICATED. That's 403 mph INDICATED; probably 430 to 450 mph true, depending on atmospheric conditions and altitude.
Better recalculate.


----------



## yosimitesam (Nov 26, 2016)

stona said:


> Essentially that the aircraft separates from and accelerates away from the bomb.
> 
> pp156/7 of my edition of the 'Report of Joint Fighter Conference'.
> 
> ...


The bomb ejector was used on the AD Skyraider according to the Pilot's Handbook for AD-2/AD-3 and AD-4. Section 4-19 of AD-2/AD-3 pilot's handbook states:
4-19 BOMB EJECTOR. The bomb ejector provided with the fuselage bomb rack is designed to displace the bomb away from the airplane sufficiently to clear the propeller in steep dives and operates by means of a bomb ejector cartridge.

Reactions: Like Like:
1 | Like List reactions


----------



## XBe02Drvr (Nov 26, 2016)

yosimitesam said:


> The bomb ejector provided with the fuselage bomb rack is designed to displace the bomb away from the airplane sufficiently to clear the propeller in steep dives and operates by means of a bomb ejector cartridge.



By the time VietNam rolled around, and jets were bombing in the compressibity range, ejectors were required on all bomb racks to assure positive separation. In fact, the original A-5 Vigilante failed as an attack bomber because it couldn't eject its ordnance forcefully enough to reliably escape the slipstream.


----------



## stona (Nov 26, 2016)

And USN fighters, unspecified, were cleared to dive at 85 degrees, close to a true vertical, with no danger of the bomb hitting the propeller.
Same for the P47.
There are complicated aerodynamic forces at work.

Reactions: Like Like:
1 | Like List reactions


----------



## Timppa (Nov 27, 2016)

XBe02Drvr said:


> ,
> Better recalculate.



I did, and still the bomb will meet the propeller in one second.




> And USN fighters, unspecified, were cleared to dive at 85 degrees, close to a true vertical, with no danger of the bomb hitting the propeller.


F4U, specified, limited the dive angle to 60 degrees, see post #8.


----------



## stona (Nov 27, 2016)

Timppa said:


> F4U, specified, limited the dive angle to 60 degrees, see post #8.



By the British, not the USN. I do not know whether the USN applied the same limits to this type of aircraft when dive bombing or not. It might be worth checking though.
Cheers
Steve


----------



## tomo pauk (Nov 27, 2016)

stona said:


> And USN fighters, unspecified, were cleared to dive at 85 degrees, close to a true vertical, with no danger of the bomb hitting the propeller.
> Same for the P47.
> There are complicated aerodynamic forces at work.



The P-47 and P-51 were in better position than F4U or F6F when it is about making a dive bomb attack, since the bombs were attached to the wings. The danger in hitting prop was probably not present there, unlike the with USN heavy fighters.


----------



## stona (Nov 27, 2016)

I have seen other ordnance in this position too.







I've no idea what the configuration for the tests was, but there was obviously some concern that the propeller might be hit, both from the 8th AF and USN.

Cheers

Steve

Reactions: Like Like:
1 | Like List reactions


----------



## GrauGeist (Nov 27, 2016)

The P-47 could (and did) carry ordnance on the centerline rack.

While they didn't "dive bomb" in the literal sense, they did deliver bombs onto enemy positions from a shallow dive. To what degree on a dive, I am not sure.


----------



## BiffF15 (Nov 27, 2016)

GrauGeist said:


> The P-47 could (and did) carry ordnance on the centerline rack.
> 
> While they didn't "dive bomb" in the literal sense, they did deliver bombs onto enemy positions from a shallow dive. To what degree on a dive, I am not sure.
> 
> View attachment 358875



Nice shot of the paddle blade prop too!


----------



## tomo pauk (Nov 27, 2016)

stona said:


> I have seen other ordnance in this position too.
> <snip>
> I've no idea what the configuration for the tests was, but there was obviously some concern that the propeller might be hit, both from the 8th AF and USN.





GrauGeist said:


> The P-47 could (and did) carry ordnance on the centerline rack.
> While they didn't "dive bomb" in the literal sense, they did deliver bombs onto enemy positions from a shallow dive. To what degree on a dive, I am not sure.



Of course you're right.
Just going with wing-only bombs on the P-47, plus the drop tank under centreline if dive bomb attack is planned will negate any fear that bomb will hit the prop during the attack. The centreline bomb is also further away from the prop center than it will be the case with a bomb attached to the Corsair's centreline rack.


----------



## GrauGeist (Nov 27, 2016)

BiffF15 said:


> Nice shot of the paddle blade prop too!


Thanks!

That P-47D belonged to the 356th FS, flown by Lt. Davis, taken in 1944.



tomo pauk said:


> Of course you're right.
> Just going with wing-only bombs on the P-47, plus the drop tank under centreline if dive bomb attack is planned will negate any fear that bomb will hit the prop during the attack. The centreline bomb is also further away from the prop center than it will be the case with a bomb attached to the Corsair's centreline rack.


Once the "Jug" has reached it's objective, the drop-tank will have been jettisoned as it would be a huge liability in the event it's struck by ground fire.


----------



## chuter (Nov 27, 2016)

stona said:


> I have found the relevant page in the 8th AF history.
> 
> 
> 
> ...




This technique appears to be essentially a split-S with bomb release at vertical. This could, depending on how tight the pilot holds the maneuver ("pulling through sharply" or not), induce likely no less than two Gs. The result being the bomb would accelerate away from the aircraft faster than it would accelerate forward (down) relative to the aircraft. If one were to try a sustained vertical dive release there is very little doubt (in the reality that is my mind - lol) the bomb would strike the prop. 

Related thoughts in general:
Terminal velocity is based on the relationship between mass of object, surface area of object and air density (and temperature, for Mach effects).

The Hellcat had the same landing gear dive brake function as the Corsair. In both cases the tailwheels were left retracted because they a) didn't create much useful drag and b) the tailwheel doors were less durable. If dive brakes were activated at excess speed they simply didn't extend all the way.


----------



## XBe02Drvr (Nov 28, 2016)

[QUOTE="chuter, ]
Terminal velocity is based on the relationship between mass of object, surface area of object and air density (and temperature, for Mach effects).
[/QUOTE]
You left out one critical item: the drag co-efficient of the object's shape. A modern low drag bomb will have a higher terminal velocity than a chunky WWII era bomb of the same diameter/frontal area. 32 ft/sec/sec is the same regardless of mass, so mass doesn't enter into it.
Cheers


----------



## XBe02Drvr (Nov 28, 2016)

XBe02Drvr said:


> [QUOTE="chuter, ]
> Terminal velocity is based on the relationship between mass of object, surface area of object and air density (and temperature, for Mach effects).


 32 ft/sec/sec is the same regardless of mass, so mass doesn't enter into it.
[/QUOTE]
OOPS! That was a Delta Sierra on my part. What passes for my brain is a little foggy at 4 AM. Serves me right, shoulda been snoring, not posting!

Reactions: Like Like:
1 | Like List reactions


----------



## stona (Nov 28, 2016)

chuter said:


> This technique appears to be essentially a split-S with bomb release at vertical. .



Essentially yes. 
The pilot pulling through vertical simply has the same effect as, in a purpose built dive bomber, the automatic dive recovery system would as it activated on bomb release.

I appreciate some might not have the entire document to put the page I reproduced into context, but there are a couple of important points which I will quote

_"The P-47s were equipped with a B-7 type bomb shackle (the belly tank release mechanism). No other sighting device was used except the 100 mile reflector gun sight. No lines were drawn on the canopy to give angle of dive as this is not practical and of no great help."_

The bombs were carried under the belly of the aircraft in these trials.

The vertical bombing technique described in the excerpt previously posted was developed because of the P-47s rapid acceleration in a dive. The report noted that there is a happy medium for accuracy between angle of dive (the steeper the better) and bomb release altitude (lower being better, with certain limits). A 60 degree dive from 10,000 ft with a pull out at 4,000 ft gave best results, though a 70 degree dive from 20,000-22,000 ft with a pull out at 16,000 ft gave reasonable results too. The technique for near vertical release could be started as low as 7,000 ft and ,given a loss of 4,000 ft, completed at 3,000 ft. For defended targets it would be started at 20,000 ft.

_"It is superior to dive bombing from a lesser angle of dive because it offers a much higher degree of accuracy with no accompanying disadvantages."_

The tactics developed were for a flight of four aircraft to attack in_ 'string formation'_, which I assume is American for in line astern, at 30 second intervals and with each pilot aiming independently.

Cheers

Steve





.

Reactions: Like Like:
1 | Like List reactions


----------



## Freebird (Dec 1, 2016)

Timppa said:


> I did, and still the bomb will meet the propeller in one second.
> 
> F4U, specified, limited the dive angle to 60 degrees, see post #8.





GrauGeist said:


> The P-47 could (and did) carry ordnance on the centerline rack.
> 
> While they didn't "dive bomb" in the literal sense, they did deliver bombs onto enemy positions from a shallow dive. To what degree on a dive, I am not sur



An aircraft had to be able to bomb at an angle greater than 60 deg. to be considered a dive bomber correct?
So did the Corsair attack at 60-85 deg. angle, or was it limited to 60 deg. "glide bombing"?

Was the limited area (and braking capacity) of the landing gear flaps enough to permit high angle dives, or was it just used for braking capability in shallow angle (<60 deg) dives?


----------



## XBe02Drvr (Dec 4, 2016)

If you read carefully all the previous posts, you'll realize that in practical terms the USN, which was then operating primarily F6Fs and F4Us had determined that prop strike was not an issue up to 85 degrees dive angle. We can argue theory till the cows come home, but fact is, they were there, they figured it out, and it worked for them.
I can easily see how a fighter pulling into a 70-80 degree dive from a moderate altitude at low cruise power and <200 KIAS with dive brakes extended would have plenty of time to acquire the target, correct for drift and dive angle, and release the bomb while still accelerating and well before terminal velocity.
From personal experience (unauthorized simulated dive bombing experiments in a T-34 in the days of young and foolish!), I can vouch for the fact that in the dive you're going to be holding a lot of forward pressure on the stick. (Unless you've retrimmed for dive speed, which would make the pullout kind of chancy.) Therefore the moment you relax that pressure the plane is going to snatch itself away from the bomb's trajectory.
I found I could roll in at 10,000 ft, terminal at about 6, (boxy, draggy, crate!), stabilized dive to 4, and consume 3,000 feet in a 3-4 G pullout. If one had a stronger airframe, better G tolerance, and larger gonads, obviously they could accomplish this profile from a lower initial altitude.
Cheers,
Wes

Reactions: Like Like:
2 | Like List reactions


----------



## BiffF15 (Dec 4, 2016)

XBe02Drvr said:


> If you read carefully all the previous posts, you'll realize that in practical terms the USN, which was then operating primarily F6Fs and F4Us had determined that prop strike was not an issue up to 85 degrees dive angle. We can argue theory till the cows come home, but fact is, they were there, they figured it out, and it worked for them.
> I can easily see how a fighter pulling into a 70-80 degree dive from a moderate altitude at low cruise power and <200 KIAS with dive brakes extended would have plenty of time to acquire the target, correct for drift and dive angle, and release the bomb while still accelerating and well before terminal velocity.
> From personal experience (unauthorized simulated dive bombing experiments in a T-34 in the days of young and foolish!), I can vouch for the fact that in the dive you're going to be holding a lot of forward pressure on the stick. (Unless you've retrimmed for dive speed, which would make the pullout kind of chancy.) Therefore the moment you relax that pressure the plane is going to snatch itself away from the bomb's trajectory.
> I found I could roll in at 10,000 ft, terminal at about 6, (boxy, draggy, crate!), stabilized dive to 4, and consume 3,000 feet in a 3-4 G pullout. If one had a stronger airframe, better G tolerance, and larger gonads, obviously they could accomplish this profile from a lower initial altitude.
> ...



Actually the USAF taught running nose down trim on downwind or base for your pass. The reason is at bomb release you want the plane on dive angle, on release speed, at release altitude in trim so there are no adverse forces at pickle. From roll in to pickle is usually a max of five seconds or you are predictable to long for triple A.

Cheers,
Biff

Reactions: Like Like:
2 | Like List reactions


----------



## XBe02Drvr (Dec 5, 2016)

BiffF15 said:


> Actually the USAF taught running nose down trim on downwind or base for your pass. The reason is at bomb release you want the plane on dive angle, on release speed, at release altitude in trim so there are no adverse forces at pickle. From roll in to pickle is usually a max of five seconds or you are predictable to long for triple A.
> Cheers,
> Biff


Navy taught likewise - in jets - with top hat trim controls - and ejector racks. I wasn't going to risk fumbling around for the manual trim wheel while pulling G at low altitude with no G suit. Nor did I want to be committed to a heavy stick-force pullout while possibly greyed out down low. Besides, I found stick forces were manageable and I could hold my grease pencil "bombsight" steady "on target" with the necessary offsets. Needless to say the "Teenie-Weenie" would not be the weapon of choice against a defended target.
We had a retired former SPAD driver in the club, who went with me a couple times and said they did pretty much the same thing in the A-1.
Cheers
Wes

Reactions: Like Like:
1 | Like List reactions


----------



## stona (Aug 12, 2017)

When the British started to hang bombs on Spitfires Flight Lieutenant Len Thorne of the AFDU (Air Fighting Development Unit) was given the task of devising suitable tactics. He later recalled:

_"When they first started hanging bombs on Spitfires, we were given the job of the best way of ensuring accuracy. Obviously, the most effective way was to get enough altitude, point the nose straight at the target in a very steep dive and let the bomb go. However, when we proposed this method of attack to the squadrons, they wouldn't have it as they were concerned that the bombs would hit the aircraft after release. To find out one way or the other, 'Wimpy' Wade [Squadron Leader T S Wade DFC, later chief test pilot at Hawker Aircraft] and myself flew two Spitfires, one of which was carrying a bomb, while the other had a camera fitted behind the pilots seat, pointing sideways. The camera aircraft had a white dot on the end of the wing and the pilot lined up the dot with the bomb on the other aircraft. By such means we got the actual moment of release on film.
'Wimpy' Wade, who was an excellent pilot, did the bomb dropping and I had to remain tucked in tight with whatever he did. We evolved the method that you overflew the target, then looked back behind the trailing edge of the wing and as soon as you could see the target you pulled up into a wing over to the inverted and then pulled back on the stick until you were headed for the target in a dive of almost exactly 70 degrees. I filmed right through the sequence and it was discovered that the bomb never went anywhere near the aircraft. In the dive you were fairly screaming down at 480 mph so the first thing you did was to commence your pull out and as a result quickly left the bomb behind. This method was eventually adopted for all high level bombing attacks. I did quite a lot of this type of work over the Holbeach range in the Wash, but I absolutely hated it, in my opinion bombing was a complete misuse of a fighter!"_

These did become standard tactics as he says, I have seen them described exactly as this in a manual for Typhoon pilots.The AFDU had to develop tactics acceptable to the squadrons AND in which the average service pilot could be easily trained. There would have been no point in developing a tactic which a test pilot like Squadron Leader Wade could fly but which the average Pilot Officer could not.

Thorne's opinion of fighter-bombing was shared by many experienced RAF fighter pilots, although a young man still in his early twenties, he had joined the RAF in 1940 and had plenty of operational experience.

You'll also notice that the film revealed, at least for a 480 mph Spitfire, that the bomb was quickly left behind.

Cheers

Steve

Reactions: Like Like:
1 | Like List reactions


----------

