Engine power is too low

[DmitriKozlowsky]

In NEvada cold start quick mission. With empty aircraft and 900 lbs of fuel TOT.  There is not enough power to T/O , hover or vertically land, without water. Thats a weak engine. DCS: AV-8B empty cannot VTOL vertically or hover in Nevada even with 650 fuel and no water. Water was added so AV-8B can land with 2 X AIM-9M, gunpod, and 650 lbs of fuel vertically on ship. Empty AV-8B with no stores and 650 should be able to hover without water.

[BJ55]

Open the quickstart mission with mission editor, change the loadout, save the mission in a different folder (my missions), start the mission and... Fly! All default AV-8B missions are not maintained since... Who knows?

 

[Holbeach]

8 hours ago, DmitriKozlowsky said:

In NEvada cold start quick mission. With empty aircraft and 900 lbs of fuel TOT.  There is not enough power to T/O , hover or vertically land, without water. Thats a weak engine. DCS: AV-8B empty cannot VTOL vertically or hover in Nevada even with 650 fuel and no water. Water was added so AV-8B can land with 2 X AIM-9M, gunpod, and 650 lbs of fuel vertically on ship. Empty AV-8B with no stores and 650 should be able to hover without water.

Hot and high means less power than on a ship.

..

[DmitriKozlowsky]

You are saying I am wrong. With capital R. THat the engine power is correct.

[DmitriKozlowsky]

Awright. I did some VTOL work in Guam. Honesty compels to walk back the engine power bug complaint. I guess 1850 foot altitude, less then 1/3 of mile, does require AV-8B to use water injection in Nevada.

[SloppyDog]

On 6/21/2024 at 3:01 AM, DmitriKozlowsky said:

Awright. I did some VTOL work in Guam. Honesty compels to walk back the engine power bug complaint. I guess 1850 foot altitude, less then 1/3 of mile, does require AV-8B to use water injection in Nevada.

I've tried the same mission with the default loadout in a rolling take off and was able to take off with no problems.

Then I tried the same mission with a VTO - Vertical Take Off. In order to do that, however, I had to change the loadout to two Sidewinders and 54% of fuel. That's it. The trick with the Harrier is that you must be below 20,500 lbs in order to hover, vertically take off or land. Considering that Nellis is at 1,853 feet, that's a complicated proposition for the Harrier, but I was able to do it, as it can be seen on the attached track file. 

AV-8B Cold Start Nevada.trk

[DmitriKozlowsky]

Try without water injection. You'll find it next to impossible. Water injection was not originally in design of  Harrier. It was added , during late development, at 'suggestion' of US Marine Corps, after marines joined Harrier program.

As technology water injection is 'weird'. Its really old tech, predating jet engines. Water is 1000X denser then air. Spraying demineralized water turns mist into steam and it it ejected along with exaust gas out of nozzles. Becouse it is 1000X denser, it increases thrust, but it also cools down combustion chamber, causing incomplete , inefficient fuel burn. Thus overall thrust is increased,  but fuel burn is lowered, so exaust is dark and sooty. Its not very apparant in Harrier II as design is optimized, but its still there in photos. Bcouse water injection increases fuel usage dramatically and amount of water carried is limited, water is 100X heavier then fuel, use is limited to T/O and landings.

Earlier water injection implementation can be seen on 1950's B-47 and B-52 departures. Engines exause is dark soot. Gross!

I do not know if SR-71's J-58 used water injection. I guess its still classified.

[Сиваш]

В 22.06.2024 в 10:09, SloppyDog сказал:

Я попробовал выполнить ту же миссию с комплектом снаряжения по умолчанию в режиме взлета с разбега и смог взлететь без проблем.

Затем я попробовал выполнить ту же миссию с VTO - Vertical Take Off. Однако для этого мне пришлось изменить загрузку на два Sidewinder и 54% топлива. Вот и все. Хитрость с Harrier в том, что для зависания, вертикального взлета или посадки вам нужно быть ниже 20 500 фунтов. Учитывая, что Неллис находится на высоте 1853 футов, это сложная задача для Harrier, но я смог это сделать, как видно из прикрепленного файла трека. 

AV-8B Холодный старт Nevada.trk 2.39 \u041c\u0411 · 15 ботинок

 

[Сиваш]

"AV-8B Night Attack aircraft is powered by the Rolls Royce F402-RR-408 
dual spool, axial flow, turbo fan engine with thrust-vectoring exhaust 
nozzles.  
The 408 engine is equipped with water injection and can develop a 
nominal thrust of 23,400 pounds with water injection, or 22,200 
pounds without water injection"!!!!!

[Gunnar81]

I did another test and I think you might be onto something here. I had to go around 600lbs below the stated fuel weight on the VL page before I could maintain a hover danger of dropping into the water. Basically I used the 'Dry' weight, dropped my fuel by 600lbs and used Water while landing. So MAYBE either the engine isn't producing enough thrust or the VL page is displaying incorrect values for fuel weight?

Hard to say what is going on here.

For clarity I was landing on the Tarawa at Sea Level, had a total weight of around 19,000lbs.

Edited November 17, 2024 by Gunnar81

[Gunnar81]

On 6/22/2024 at 12:09 AM, SloppyDog said:

I've tried the same mission with the default loadout in a rolling take off and was able to take off with no problems.

Then I tried the same mission with a VTO - Vertical Take Off. In order to do that, however, I had to change the loadout to two Sidewinders and 54% of fuel. That's it. The trick with the Harrier is that you must be below 20,500 lbs in order to hover, vertically take off or land. Considering that Nellis is at 1,853 feet, that's a complicated proposition for the Harrier, but I was able to do it, as it can be seen on the attached track file. 

AV-8B Cold Start Nevada.trk 2.39 MB · 15 downloads

I think this is the answer here. 20,500lbs is the MAX weight at perfect conditions at sea level with a strong head wind and the Tarawa going 20kts into that head wind. Even then you'll be using water just to transition and maintain a hover. With any kind of warm air temp and no head wind to transition into its going to be even harder on the jet. Gotta dump more fuel or stores as the conditions change regardless of what the VL values show on the MFD.

I assumed the MFD values were showing what weights were permissible with the current conditions but maybe they are showing 'ideal' conditions? This I don't know.

[QuasarZero]

I think it's related to the altitude of the region.

The average altitude in Nevada is over 5000 feet, and the air in higher altitude areas is thinner, the amount of air intake required for vertical takeoff and landing decreases, and the engine output power decreases, thereby lowering the maximum vertical weight you can achieve during vertical takeoff and landing.

In the same situation, you can try flying a helicopter in Nevada.

[SloppyDog]

On 11/18/2024 at 10:01 PM, Gunnar81 said:

I think this is the answer here. 20,500lbs is the MAX weight at perfect conditions at sea level with a strong head wind and the Tarawa going 20kts into that head wind. Even then you'll be using water just to transition and maintain a hover. With any kind of warm air temp and no head wind to transition into its going to be even harder on the jet. Gotta dump more fuel or stores as the conditions change regardless of what the VL values show on the MFD.

I assumed the MFD values were showing what weights were permissible with the current conditions but maybe they are showing 'ideal' conditions? This I don't know.

I looked in the module manuals and in Chuck's Guides and the only warning regarding the weight is that it must not be above 20,500 lbs. No notes regarding the conditions at this limit is applicable. But, it may be for ideal conditions. For higher altitudes and temperatures this limit must be lower. 

The maximum values for Fuel and Water (F+W) should be given by the VREST VL page for the atmospheric conditions at the moment of landing , but I tested and it seems that they are not working properly. 

Edited November 20, 2024 by SloppyDog

[Tomcatter87]

I had trouble yesterday landing on a ship, just plunged into the water, at full thrust and with water injection. Loadout was only a Tpod and two mostly empty Tanks, fuel was around 6000. Pretty sure I had heavier landings. Temperature couldn't be a factor at all, I was off the Norwegian coast at minus 20 degrees. We have so many reports about this, hope someone can look at it and provide a fix. 

[Holbeach]

6 hours ago, Tomcatter87 said:

I had trouble yesterday landing on a ship, just plunged into the water, at full thrust and with water injection. Loadout was only a Tpod and two mostly empty Tanks, fuel was around 6000. Pretty sure I had heavier landings. Temperature couldn't be a factor at all, I was off the Norwegian coast at minus 20 degrees. We have so many reports about this, hope someone can look at it and provide a fix. 

Wow, 6000 is too much. With a TP only, about 4000 max.

Gun and Sidewinders, about 2500.

Idealy with with the ship at speed, into a headwind and at Sea Level.

..

[Gunnar81]

13 minutes ago, Holbeach said:

Wow, 6000 is too much. With a TP only, about 4000 max.

Gun and Sidewinders, about 2500.

Idealy with with the ship at speed, into a headwind and at Sea Level.

..

This. With 2 empty fuel tanks and a TPOD with 6000lbs of internal fuel means you were around 3000lbs overweight if, as Holbeach said you had ideal ship and wind conditions. In a perfect scenario you want less then 20,000lbs gross weight if you can manage. I typically dump fuel till I have about 2,000lbs internal which gives enough for one wave off and retry. After that they need to get the rescue chopper ready lol.

[Tomcatter87]

Wow, okay. I'm used to the Tomcat, tanking for a max trap weight on recovery. Thanks, guys!

[Сиваш]

Вчера я снова проверил его, и я все еще не мог оторваться от земли, на полной тяге, только с пушкой и 1200 фунтами топлива. Привет, Разбам, когда ты починишь самолет! Я больше никогда ничего не куплю у этой компании!

Edited January 14 by Сиваш

[AirSenpai]

On 1/14/2025 at 1:10 PM, Сиваш said:

Вчера я снова проверил его, и я все еще не мог оторваться от земли, на полной тяге, только с пушкой и 1200 фунтами топлива. Привет, Разбам, когда ты починишь самолет! Я больше никогда ничего не куплю у этой компании!

If you are not facing the wind direction, you won't hover.
The plane is a STOVL (short take off/vertical landing)
All operations with the jet when the plane was designed, was to to take off from short-runways , and land with very low fuel on the vertical like a helicopter.
try using this tip.

 

[Fisu_MAD]

Try the stock mission Vertical Takeoff. 22000 lb when is needed <20500. Weight problem?? maybe,...