Harrier STOL capability?

Skapa
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Re: Harrier STOL capability?

Postby Skapa » Sun 27 Apr 2014 23:47

integ3r wrote:
Skapa wrote:
DanJLloyd wrote:No, there are no hovering jets in this game - there are game engine limitations.


I couldn't possibly comment about the game engine part, but the Harrier is unable to use it's VTOL capability in combat with any form of practicality. The Pegasus engine used by the Harrier generates an enormous amount of heat and uses water injection to maintain an ambient temperature that is acceptable during vertical landing. As you can imagine the water reservoir isn't exactly huge, and roughly provides 90 seconds of sustained thrust in the vertical configuration.

That's just misleading. There's enough water to continuously cool for 90 seconds. But you obviously do not need continuous cooling unless you're doing missions in the scorching desert or some such. Because of that, the harrier can hover for much much longer.



With a full combat loadout and the possibility of vertical landing, water used for cooling the hovering configuration will still make such maneuvers less than optimal in a combat scenario.

More Fuel (assuming the aircraft has gone straight to the airspace of the battlefield from take off) + a full munitions load = less time in hover to put it simply.

Now an unloaded Harrier, with no weapon stocks will of course be able to hover longer than the maximum performance figure I have mentioned, but we're not dealing with an aircraft with no combat load.

With a full combat load and respectable amount of fuel however it is simply not practical. To bring the A/C to a halt, hover and then accelerate to an optimum speed (from stand still) would be incredibly intensive on coolant levels and fuel.

The crux of this is weight. With munitions and fuel, the Harrier is heavy. To use figures from the GR. 7 [1]

The engine is capable of delivering 21, 750 lbs of thrust.

This however falls to 20280 lbs when water injection is used, I.E. in the hover configuration [2][4].

The max STO weight is 31, 000lbs (when the Harrier is launched from a ‘ski ramp’)

The max VTO weight is 18, 950lbs

The empty weight ( no fuel just the air frame) is 12, 500lb

Max fuel weight carried internally : 7 759lbs

So to start with a Harrier with full fuel (no mission payload) weighs; (12500+7759) = 20 259 lbs

Payloads can typically weigh from 2070lbs to 5067lbs

Here we see why STO is used to get a Harrier into the air. It can potentially carry more munitions and fuel (allowing for a longer mission time). The logic being that fuel will be used by the time the aircraft comes back in order for it to be light enough for the aircraft to land.
Now hovering with a payload and fuel greater that the VTO max is simply not possible. To hover with a combat payload one must ditch fuel.

Less fuel = less flight time.

How will the pilot get home if fuel and coolant is exhausted hovering? The aircraft needs fuel to return to base and more importantly, land in the vertical configuration. Which not only uses fuel but also coolant.

TL;DR : Harriers hovering for several minutes at an airshow is one thing, but a Harrier with a combat payload would most certainly not be able to maintain anywhere near as long a hovering flight duration as the aircraft would be too heavy for the engines and to carry the sufficient fuel to make this remotely possible.

Sources:
[1] : “Royal Air Force Aircraft & Weapons” http://www.raf.mod.uk/rafcms/mediafiles ... 7857da.pdf
Retrieved 27th March 2014
[2]: “NATOPS FLIGHT MANUAL NAVY MODEL AV--8B/TAV--8B 161573 AND UP AIRCRAFT” (2008) Naval Air Systems Command, Patuxent River, MD, USA.
[3]: “Standard Aircraft Characteristics NAVY MODEL AC-8B HARRIER II AIRCRAFT” (1986) Naval Air Systems Command, Patuxent River, MD, USA.
[4]: Roux, E. (2007) “Turbofan and Turbojet Engines: database handbook” , Blagnac: Editions´Elodie Roux
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Warhero1221
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Re: Harrier STOL capability?

Postby Warhero1221 » Mon 3 Aug 2015 03:17

A Harrier's VTOL or (Vertical Takeoff & Landing) ability was purely for logistical purposes required by the marine corps. Though I admit, it'd be cool to have a harrier hover over a defenseless rifle squad and pick them off with it autocannons.

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Re: Harrier STOL capability?

Postby Xeno426 » Mon 3 Aug 2015 04:38

Warhero1221 wrote:A Harrier's VTOL or (Vertical Takeoff & Landing) ability was purely for logistical purposes required by the marine corps.

Well, since the Brits don't have a marine corps (as a separate branch), I think you may be misinformed.
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CloakandDagger wrote:And you're one of the people with the shiny colored name. No wonder the game is in the state it's in.

Warhero1221
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Re: Harrier STOL capability?

Postby Warhero1221 » Mon 3 Aug 2015 04:51

I was talking about the AV-8B Harrier that the USMC use and is available in-game as a Marine-type multi-role airplane for the US

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Re: Harrier STOL capability?

Postby themediocrity » Tue 4 Aug 2015 05:05

Attempting a vertical landing in a combat environment would be suicidal. You're there hovering and slowly descending as basically a static target one R-27 comes your way and what the hell do you do? You have no speed and no altitude. You might as well fly your plane into a mountain. Aircraft already reload and return probably 100 times faster than is realistic so I'm not sure how much faster you could possibly expect to reload a plane (AFAIK a combat-loaded Harrier can't launch vertically anyway so it would just be stuck where it landed until a shell hit it).

That sort of Battlefield crap is not needed.

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Re: Harrier STOL capability?

Postby molnibalage » Tue 4 Aug 2015 11:52

Harrier is not a helicopter. Period.

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Re: Harrier STOL capability?

Postby Vulcan 607 » Tue 4 Aug 2015 13:44

Warhero1221 wrote:A Harrier's VTOL or (Vertical Takeoff & Landing) ability was purely for logistical purposes required by the marine corps. Though I admit, it'd be cool to have a harrier hover over a defenseless rifle squad and pick them off with it autocannons.


The guns are fixed the best it could do hovering over an enemy squad is cook them assuming it doesn't get shot down straight away.

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Re: Harrier STOL capability?

Postby Xeno426 » Tue 4 Aug 2015 22:43

Warhero1221 wrote:I was talking about the AV-8B Harrier that the USMC use and is available in-game as a Marine-type multi-role airplane for the US

The AV-8B was a joint upgrade between BAe and McDonald Douglas of the original Harrier, which was a purely British venture, so saying the VTOL capability (something the original Harrier had) was made for the Marines is incorrect. The Marines were interested in it because of the VTOL capability, not the other way around.
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