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Climb rate vs descend rate

Posted: Sat Oct 19, 2013 3:48 am
by Yaab
Ki-43 Oscar has the best climbing rate (3490 feet) at the start of the war. Does it mean that its descend rate will be similar to its climb rate? Oscars were light aircraft, which , I guess, would hurt their diving speeds.Seems like heavy fighters (i.e Warhawks) should have best descend rates.Or maybe it is the max speed that matters most? If so, Aircobra would make fastest descends.

How is climb rate related to descend rate?

Thanks.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 4:00 am
by sandman455
ORIGINAL: Yaab

How is climb rate related to descend rate?

Thanks.

It's not.

And yes your assessment that diving speeds are directly related to Vne (Never exceed speed) is correct. Vne is not part of the game so the rate at which an aircraft could dive is also not part of the A2A model. Most aircraft that did have a very good Vne are well represented in the stock scenarios. You aren't missing much except for a few Japanese aircraft that had a rather large split in their Vh (max speed level flight) over Vne. They would have performed better than presented against the high energy tactics of the allies late war.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 6:18 am
by Yaab
Interesting. I thought the diving speeds were part of the code, at least for the kamikaze diving attacks.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 10:04 am
by dr.hal
Read books like Wings of Gold, where it is articulated that a major defense tactic of Allied aircraft was the dive to get OUT of an attack. The reason is simple, a heavy aircraft can fall quicker than a light aircraft as both would have engines that can assist, but the advantage goes to the aircraft whose frame is helped by gravity. Also keep in mind that the famous defensive move against the Zero, the Thatch weave, was a tactic used in a dive, NOT a climb...

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 10:33 am
by KenchiSulla
As far as I know the Thatch weave is not executed in a dive. It is executed in the horizontal plane and if you use in combat sims it is very effective to disengage. Fire power is important, roll rate is of secondary importance..

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 10:44 am
by JocMeister
ORIGINAL: Cannonfodder

As far as I know the Thatch weave is not executed in a dive. It is executed in the horizontal plane

That was my understanding too.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 10:59 am
by dr.hal
Well not really, the move is done by loosing altitude. Note this rather detailed description: http://combatgears.wordpress.com/2013/0 ... ach-weave/ and note that the wing man does "dive" to get "under" the enemy to get a under belly shot. I guess in the strictest sense one could say it is horizontal but both defending aircraft loose altitude doing this maneuver. This is understandable as the Wildcat could not compete in a climb.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 12:38 pm
by LoBaron
Thach Weave was a horizontal ACM.

The reason for Jimmy Thach that he "dived under his wingman and fired at the incoming enemy aircraft’s belly" was because he had to avoid a head on collision with Dibb first. That does not make the Thach Weave vertical.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 12:48 pm
by dr.hal
Sorry for the misunderstanding, I certainly wasn't suggesting it was "vertical" in any way shape or form. But back to the original point of this thread, the US navy fighters at the time could out dive their Japaneses adversaries. It was an effective defensive maneuver which took advantage of the few "superior" characteristics of the US fighters at the time; their weight and compact size (relatively speaking).

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 1:37 pm
by Yaab
My question was concerned with medium altitude CAP and bombers sneaking underneath it to attack shipping at the base. I just don't know how fast such CAP can descend to catch the bombers. Without radar there is little time to react to bombers and I saw CAP at 10,000 feet who wouldn't intercept the bombers attacking at 5000-6000 feet.

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 1:50 pm
by Sieppo
How does weight affect dropping speed?

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 4:43 pm
by Alfred
This might be an interesting discussion for some people but as far as this game is concerned the answer was provided in the first 2 words of post #2.

So the "discussion" is irrelevant for kamikazes, descent speed, weight or anything else.

Alfred

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 5:11 pm
by Erkki
ORIGINAL: Sieppo

How does weight affect dropping speed?


Because heavier planes tend to have more mass for comparable effective resisting aerodynamic cross-section than the lighter planes.

Two objects of similar size but different mass do have the same initial falling acceleration, but the heavier one will have higher (top)falling speed in same g, air pressure yadda yadda. [:)]

RE: Climb rate vs descend rate

Posted: Sat Oct 19, 2013 6:25 pm
by Sieppo
ORIGINAL: Erkki

ORIGINAL: Sieppo

How does weight affect dropping speed?


Because heavier planes tend to have more mass for comparable effective resisting aerodynamic cross-section than the lighter planes.

Two objects of similar size but different mass do have the same initial falling acceleration, but the heavier one will have higher (top)falling speed in same g, air pressure yadda yadda. [:)]

ok thanks :)

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 2:40 am
by rustysi
Also, generally speaking heavier AC (I'm speaking in terms of fighters here) tend to have better structural integrity which allow them to withstand the strains of a higher dive speeds. Dive too fast and lighter AC will experience structural problems, never a good thing. [X(]

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 11:57 am
by HexHead
ORIGINAL: Erkki

ORIGINAL: Sieppo

How does weight affect dropping speed?


Because heavier planes tend to have more mass for comparable effective resisting aerodynamic cross-section than the lighter planes.

Two objects of similar size but different mass do have the same initial falling acceleration, but the heavier one will have higher (top)falling speed in same g, air pressure yadda yadda. [:)]

Yes, no, need to rewrite (unclear). Please let me suggest:

The terminal velocity (i. e., in effect, the velocity at any desired time, as is noted immediately below) of a freely accelerating body (note that 'freely accelerating' necessarily implies no other forces acting on the body) is given by:

v sub t = 1/2 (acceleration due to the local gravitational field) (t^2)

in other words, in a vacuum. If one does the work (see Elementary Differential Equations), the result is that when air resistance is allowed for, most objects reach a terminal velocity that is an upper bound. This value for people is around 180 mph and is roughly the same for most objects. The most important aspect is the cross-section of the falling object - and, remember, still only two forces, g and air resistance.

A Jug outdove everything, partly because of mass, partly because of the powerplant. More mass, well distributed, aids in diving, turning, etc.

No, the air model, afaics, does not model AVG tactics in China. Too bad Jugs can't hover at 35K and smash all below with near impunity.

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 12:21 pm
by HexHead
To be absolutely clear: the airplane is zooming around at 300 mph; as a rock, it would be in the neighborhood of 200 mph; so, the rate at which the plane is 'knocking air out of the way', no matter the orientation, is very important. Also, this way of looking at it shows that there is an upper bound to knocking air out of the way - the sound barrier. I don't know if a prop of any kind ever exceeded 600 mph.

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 12:26 pm
by HexHead
And, although completely untutored in aeronautical engineering, it should be apparent that lighter masses (e. g., Zekes) can, pari passu, can have a higher ceiling and maneuver better in thinner air densities. Yeah, that seems to be modeled. But I wouldn't expect Claire Chennault to be diving on packs of Zeroes anytime soon.

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 1:41 pm
by Erkki
ORIGINAL: HexHead
ORIGINAL: Erkki

ORIGINAL: Sieppo

How does weight affect dropping speed?


Because heavier planes tend to have more mass for comparable effective resisting aerodynamic cross-section than the lighter planes.

Two objects of similar size but different mass do have the same initial falling acceleration, but the heavier one will have higher (top)falling speed in same g, air pressure yadda yadda. [:)]

Yes, no, need to rewrite (unclear). Please let me suggest:

The terminal velocity (i. e., in effect, the velocity at any desired time, as is noted immediately below) of a freely accelerating body (note that 'freely accelerating' necessarily implies no other forces acting on the body) is given by:

v sub t = 1/2 (acceleration due to the local gravitational field) (t^2)

in other words, in a vacuum. If one does the work (see Elementary Differential Equations), the result is that when air resistance is allowed for, most objects reach a terminal velocity that is an upper bound. This value for people is around 180 mph and is roughly the same for most objects. The most important aspect is the cross-section of the falling object - and, remember, still only two forces, g and air resistance.

A Jug outdove everything, partly because of mass, partly because of the powerplant. More mass, well distributed, aids in diving, turning, etc.

No, the air model, afaics, does not model AVG tactics in China. Too bad Jugs can't hover at 35K and smash all below with near impunity.

Hello,

What "AVG Tactics"? How does having more mass help in turning? [:)]

How are P-47s going to smash all below with near impunity if they are too high to see anything and too high to attack without getting lower even if they did? The in-game A-A goes both ways: you cant tell your guys to avoid combat when at a numerical or other disadvantage vs. Zeros but gtfo out instead if theres bo bombers to shoot and thus a prize worth the risk, and similarly you cant tell your Zero pilots late in the war to not climb to engage a stratosphere-cruising enemy. The formations will always clash. One can pretty much just tell them to fly or not fly. Its not like micromanaging them much further would be the job of a theater commander any way. That combined to formations also always finding each other if in the same hex are probably one of the reasons(among many others) why the in-game air campaigns tend to be much bloodier than in real life...

Also. P-47 and A6M can both dive exactly as fast... They can both reach a speed of, lets choose 900 kmph IAS. Its just that not only does the P-47 reach that speed quicker than the A6M(from similar initial level flight speed) but it does that, unlike the Zero, usually without suffering physical damage starting from 600 kmph IAS or so. As rustysi said, the heavier and bigger fighters also often had higher structural integrity. Almost all aircraft can and afaik all ww2 era aircraft could, in a steep enough dive, reach speeds far higher than their never-exceed-speed.

EDIT:
And, although completely untutored in aeronautical engineering, it should be apparent that lighter masses (e. g., Zekes) can, pari passu, can have a higher ceiling and maneuver better in thinner air densities. Yeah, that seems to be modeled. But I wouldn't expect Claire Chennault to be diving on packs of Zeroes anytime soon.


Not really lower masses per se, but lower wingloadings and higher thrust-to-weight ratios. Its not 100% set in stone though, just a rule of thumb. Maneuverability OTOH depends on a lot of things and not the least on how one defines it... Ask Commander Stormwolf.

RE: Climb rate vs descend rate

Posted: Tue Oct 22, 2013 1:46 pm
by crsutton
ORIGINAL: dr.hal

Well not really, the move is done by loosing altitude. Note this rather detailed description: http://combatgears.wordpress.com/2013/0 ... ach-weave/ and note that the wing man does "dive" to get "under" the enemy to get a under belly shot. I guess in the strictest sense one could say it is horizontal but both defending aircraft loose altitude doing this maneuver. This is understandable as the Wildcat could not compete in a climb.


Well yes, but virtually all aircraft in combat lost altitude. sustained fights tended to end up on the deck. I suppose it was just a natural reflex for pilots in a tight fight to keep losing altitude as a trade off for maintaining speed while maneuvering. So, it makes sense to me that the thatch weave would call for loss of altitude.