How important is Dive rate?

[NedYarbNexus]

Hi, I'm new here and i'm a bit of a Fighter n00bie
I've been studying warships and Tanks for a long time but I thought I'd come and study fighter planes.

I've seen an absolutely enormous amount documentation climb rates and how important it is like you could find out right now the climb rates of any fighter plane at virtually any altitude, but there is virtually nothing known about dive rates.
The way one makes their plane have a better dive rate is to simply make it heavier and the way to give a plane a better climb rate is to simply to make it lighter while giving the planes as much power as possible in the most aerodynamic frame as possible will benefit both.


Like it would seem (in a combat engagement) more important to be able to out Dive your opponent than out climb him, like if you try to out climb an enemy fighter on your tail unless your climb rate is far superior you're probably gonna get shot down since your both slowing down making you easier to hit (also being able to maneuver is limited) and because you would have started the climb your gonna start slowing down first closing the distance allowing you to get shot down.

But in a dive, (assuming your dive rate is superior to your opponent on your tail) your harder to hit because your traveling faster (and maneuverability is better) and going to get further and further away from your opponent the further you get in the dive until eventually your not only outside his attack range but is traveling faster and if you were to level off (gradually so you don't bleed heaps of E) still out run him (and if your flying a faster plane at that particular altitude, continue to out run him indefinitely).
and since you have a faster speed and have thus more energy at that particular altitude you could then put the plane into a climb and outclimb your slower flying opponent, perhaps even if his climb rate is slightly better.
(I do believe this tactic is called a zoom climb and I've heard that it was Erich Hartmann's favorite maneuver and he flew a BF109G-6 which was a light-weight plane which was poor in a dive.)
(i've also noticed that the American fighters are typically much heavier than the counterparts of other nations and thus all also have better dive rates.)

I was thinking about this if an engagement were to occur between say a P-51D Mustang and Spitfire HF IX if they both started initially at the same speed(say 400kph) and same altitude (say 25,000ft) head on.
Both have the same engine, The Spitfire IX can out maneuver, out roll and outclimb the Mustang due to its conventional elliptical wings and lighter body but the Mustang has a faster top speed at all altitudes and can dive faster due to the Laminar flow wing and a heavier body.

If the P-51D Mustang was to force a pursuing Spitfire HF IX into a zoom climb (assuming he made no mistakes and all pulls were very gradual as not to lose E) could the Mustangs superior dive rate over contest the spitfires climb rate and ultimately outclimb it?

 

[pbehn]

Nothing is ever that simple. There is the initial acceleration, the speed in the dive and the amount of control retained as speed increases. In terms of absolute high speed I believe the Spitfire was one of the fastest in a dive due to its thin wings but took longer to get to that speed and suffered from loss of control authority at a lower speed than many.

 

[Greyman]

Gross oversimplification: Climb dictates how the fight starts, dive dictates how the fight ends.

There are so many variables and nuance present in any fight - that to have any concrete answer to any of your questions isn't really possible.

As for you match-up; all things being equal, I think betting your life on zoom-climb in a dogfight vs. a Spitfire and 20-mm cannons isn't the right move. The Mustang can blast past that Spitfire during the head-on pass and head home. Come back with your wingman. Two faster Mustangs vs. two slower Spitfires - now you have options.

 

[swampyankee]

Dive rate can permit breaking off combat. Since there are books written on this topic (Amazon product ASIN 0870210599View: https://www.amazon.com/Fighter-Combat-Maneuvering-Robert-Shaw/dp/0870210599
, for example), you're not going to be able to get an answer in a few dozen words on an Internet forum.

The one generic is that successful combat pilots fly to their aircraft's strengths, not to those of their enemy. MiG-17s have been shot down by AD Skyraiders because the MiG drivers ignored that; FW190 and Bf109 pilots have been shot down by P-39s and P-40s because they ignored that; Hurricane pilots have been shot down by CR.32 and CR.42 pilots because they ignored that. Dive rate is just one of a dozen or so factors that affect air combat tactics.

 

[tomo pauk]

Hi, I'm new here and i'm a bit of a Fighter n00bie
I've been studying warships and Tanks for a long time but I thought I'd come and study fighter planes.
I've seen an absolutely enormous amount documentation climb rates and how important it is like you could find out right now the climb rates of any fighter plane at virtually any altitude, but there is virtually nothing known about dive rates.
The way one makes their plane have a better dive rate is to simply make it heavier and the way to give a plane a better climb rate is to simply to make it lighter while giving the planes as much power as possible in the most aerodynamic frame as possible will benefit both.
Like it would seem (in a combat engagement) more important to be able to out Dive your opponent than out climb him, like if you try to out climb an enemy fighter on your tail unless your climb rate is far superior you're probably gonna get shot down since your both slowing down making you easier to hit (also being able to maneuver is limited) and because you would have started the climb your gonna start slowing down first closing the distance allowing you to get shot down.

Welcome to the forum
The dive rates, or dive speeds, were within some limits. There was a term called dive speed limit, or similar, that pilots were strongly advised not to cross, otherwise the aircraft will enter into uncontrolable flight that involved compressibility problems, coupled with inability to make any maneuver that can seve the aircraft and pilot, while some aircraft will endure stress conditions that will easily damage it due to a sudden maneuver.
Out-diving assumes that both aircraft are already in about same altitude. Works well unless you have to climb up to attain the altitude the enemy is already at - hence rate of climb is very important, probably more important than the dive rate.
Heavier aircraft don't have an advantage in dive by default, especially if increased weight is not followed by increase in engine power. Just remember the Newton's apple, or Da Vinci's test with two balls falling from the Pisa tower.

But in a dive, (assuming your dive rate is superior to your opponent on your tail) your harder to hit because your traveling faster (and maneuverability is better) and going to get further and further away from your opponent the further you get in the dive until eventually your not only outside his attack range but is traveling faster and if you were to level off (gradually so you don't bleed heaps of E) still out run him (and if your flying a faster plane at that particular altitude, continue to out run him indefinitely).
and since you have a faster speed and have thus more energy at that particular altitude you could then put the plane into a climb and outclimb your slower flying opponent, perhaps even if his climb rate is slightly better.
(I do believe this tactic is called a zoom climb and I've heard that it was Erich Hartmann's favorite maneuver and he flew a BF109G-6 which was a light-weight plane which was poor in a dive.)
(i've also noticed that the American fighters are typically much heavier than the counterparts of other nations and thus all also have better dive rates.)

American aircraft, with exclusion of P-51, have had lower dive limits than Spitfire, Tempest, Bf 109 or Fw 190. The heavy P-38 was especially bad (not due to it's weight, though). Good dive limits are a function of aerodynamics and allowed G load, not weight.

I was thinking about this if an engagement were to occur between say a P-51D Mustang and Spitfire HF IX if they both started initially at the same speed(say 400kph) and same altitude (say 25,000ft) head on.
Both have the same engine, The Spitfire IX can out maneuver, out roll and outclimb the Mustang due to its conventional elliptical wings and lighter body but the Mustang has a faster top speed at all altitudes and can dive faster due to the Laminar flow wing and a heavier body.

If the P-51D Mustang was to force a pursuing Spitfire HF IX into a zoom climb (assuming he made no mistakes and all pulls were very gradual as not to lose E) could the Mustangs superior dive rate over contest the spitfires climb rate and ultimately outclimb it?

As noted by above poster, the Spitfire was actually tested as no worse diver than the P-51. Here the thin wing was paying off. Spitfire should probably enter a dive faster than P-51 due to a better power-to-weight ratio. BTW - Spitfire IX HF did not have the same engine as the P-51D (V-1650-7); the V-1650-3 on most of the P-51Bs was the Packard Merlin closest to the RR Merlin 70 series.

Some dive limits are posted here: link

 

[Greyman]

The Spitfire's ultimate dive speed may have been very competitive with the Mustang, but I think in terms of using the attribute in a real scrap the Mustang had the advantage (dive acceleration, control forces, steadiness, speed retention after pullout, windscreen condensation).

 

[pbehn]

Some Spitfire and Bf 109 pilots in the BoB would have preferred flying their opponents aircraft, the 109 could escape in a dive from the Spitfire, but since they were escorting bombers they would have preferred superiority in turn and climb, for Spitfire and especially Hurricane pilots, after attacking the bombers they would have preferred to leave the escorts by diving away. There is also the obvious consideration that the nearer you are to the ground the more the likelihood that you will hit it or someone will start firing guns at you.

 

[bobbysocks]

dive rate had to be somewhat important because it was one of the main maneuvers used. a large amount of fights started up high but ended up on the deck or closer to it.

 

[BiffF15]

dive rate had to be somewhat important because it was one of the main maneuvers used. a large amount of fights started up high but ended up on the deck or closer to it.

Bobbysocks,

It is a main maneuver if it's a strength over your adversary (almost any US metal versus a Zero). Also almost all fights, even to this day end up at the floor when maneuvering with in visual range. Altitude is exchanged for energy to keep up airspeed / turn ability.

Cheers,
Biff

 

[swampyankee]

dive rate had to be somewhat important because it was one of the main maneuvers used. a large amount of fights started up high but ended up on the deck or closer to it.

They're not diving to go down; no aircraft of the era had enough power to perform high-acceleration maneuvers without losing speed or altitude. High dive speed could permit escape, and return to the real job, either killing bombers or preventing the enemy from completing their mission. Getting shot down keeps a pilot from doing either.

 

[Barrett]

Marion Carl told of flying P-38s in SoCal when recycling VMF-223 for the 1943 F4U deployment. He knew one of the squadron COs who had flown on Guadal. The army guy appreciated the navy's overhead gunnery pattern and wanted his squadron to learn it. Marion said that speed control was crucial because the 38 was so clean that it accelerated too quickly for optimum control in the dive phase of the run. Pilots could learn the technique but I sorta recall he said it took too much time/fuel to master and was not pursued.

 

[mad_max]

From what I've gathered through the years is all aircraft of WW2 started having control issues at Mach .72. Close to Mach .80+ you were pretty much just along for the ride.

Most fighting took place at 350-400 mph during the heavy bomber raids.

 

[GregP]

I think the 350 - 400 mph would be for planes attacking the bombers. Fighter versus fighter was probably down around 280 - 350 mph due to hard maneuvering. That is assuming one-versus-one, in a dogfight. If you weren't dogfighting, it was probably around 350 - 400 mph.

 

[KiwiBiggles]

An interesting slant on the question of the importance of dive rate is, did designers ever make design choices specifically to improve dive rate? We are all fairly familiar with the design trade-offs between speed, rate of climb, manoeuvrability , range etc, but I don't think I've ever heard mention of dive rate in design decisions.

Also, given its apparent importance in combat, it's strange that dive rate is only really mentioned in subjective terms. We get mentions of the limiting mach number of the P-38 being a problem in dives, but that's about it. Otherwise, aircraft are said to be 'good at diving', and it's left there.

 

[mad_max]

I think the 350 - 400 mph would be for planes attacking the bombers. Fighter versus fighter was probably down around 280 - 350 mph due to hard maneuvering. That is assuming one-versus-one, in a dogfight. If you weren't dogfighting, it was probably around 350 - 400 mph.

I would imagine both; the fighters attacking the bombers or the fighters attacking the fighters heading for the bombers, were both in the high speed range.

Once it's 1 vs 1 fighter you're probably correct and even at those speeds your in a downward spiral fight.

I remember one P-51 ace I talked to said he never fought at low speed as it was he felt not using the Mustang to it's best. Now what was low speed I didn't think to ask him. 8-(