SF2E Cant get Harriers to VTO

[Hokum 0]

Before this goes like a previous thread. I'm not talking about the ability of the real Harriers just the ones in the game...

 

GR1 with 75% fuel and no external stores 100% thrust it gets light on the wheels but no joy other than that. This is with flaps set to takeoff and landing. If i edge the thrust forward i can STO but i sink if i try to bring speed to 0kts again. I've tried with Bobrocks GR7 too but no joy.

 

I was just showing a friend the Harriers and it just puzzled me.

[JediMaster 451]

I thought a Harrier needed to have less than 50% fuel for a VTO.

[Hokum 0]

I thought a Harrier needed to have less than 50% fuel for a VTO.

 

I dont believe so, i've seen pictures with fuel tanks and two matra rocket launchers?

[turkeydriver 4]

I dont believe so, i've seen pictures with fuel tanks and two matra rocket launchers?

The Harrier cannot take off vertically with a combat load, the pictures would be of a jet with empty external tanks and lower internal fuel. Do you have the nozzles set for VTO? It's just not gonna happen at the start of a mssion period because thats realistic, you are too heavy. When you come back to base after a successful mission you can land and then VTO and land until you run outta gas.

[Hokum 0]

The Harrier cannot take off vertically with a combat load, the pictures would be of a jet with empty external tanks and lower internal fuel. Do you have the nozzles set for VTO? It's just not gonna happen at the start of a mssion period because thats realistic, you are too heavy. When you come back to base after a successful mission you can land and then VTO and land until you run outta gas.

 

I'm aware a full war load isn't possible at least on the earlier harriers. But i believed that fuel and two pods was possible?

[+331Killerbee 840]

First Generation and Second Generation Harriers can VTO in "Real Life" with a Full Combat Load. It's just not Normally done for the Reason it takes up so much Water. The RR 402 Engine uses Water Injection it increase Compression Combustion. The Harrier's On-board Water Tank is just so Big. Hovering with Large Loads requires more Water, Let alone, Hovering "Slick".

 

But it's done. I can recall many of Times that I've personally have seen it done. Either in OPVAL. Aboard Ship. At Lyman Road at Camp Lejune, NC. And at MAF Bouge Field, NC.

[Hokum 0]

First Generation and Second Generation Harriers can VTO in "Real Life" with a Full Combat Load. It's just not Normally done for the Reason it takes up so much Water. The RR 402 Engine uses Water Injection it increase Compression Combustion. The Harrier's On-board Water Tank is just so Big. Hovering with Large Loads requires more Water, Let alone, Hovering "Slick".

 

But it's done. I can recall many of Times that I've personally have seen it done. Either in OPVAL. Aboard Ship. At Lyman Road at Camp Lejune, NC. And at MAF Bouge Field, NC.

 

Thanks KB. I thought it was possible but not usual (having seen footage of GR.3's in the Falklands doing VTO with fuel and rockets).

 

Now back to my original question, why cant i go vertical with no weapons and only 75% fuel in game? This is with the GR.1 and GR.7

[+331Killerbee 840]

I'll load some First and Second Generation Harrier this Evening in SF2E and report back My finding.........

[JediMaster 451]

What thrust do the Harrier engines have in game? Once you know that, the loadout screen tells you exactly how heavy the plane is.

 

There is no water injection modeled for any planes in the TW sims. All we get is engines with or without burner.

[+331Killerbee 840]

Rolls Royce Pegasus

 

F402-RR-406 21500 Pounds of Thrust.

 

F402-RR-408 23400 Pounds of Thrust.

[JediMaster 451]

So that's what they SHOULD have...but what do they REALLY have? If they're underpowered for some reason...

[Gr.Viper 131]

Well, VTOL is coded rather curiously in TW sims. Turn nozzles down on parking, turn engine off and move the stick about. Plane will still bank and pitch as if the turbine were running. Maybe raw jet power is reduced to take reaction control into account

 

Wiki says that Pegasus tends to overheat during long hover and water injection supply is very limited.

[+331Killerbee 840]

Due to the high engine loads experienced during hovering at high ambient temperatures, second stage high pressure turbine stator vanes in the F402-RR-406 can exceed their temperature capability and fail by cracking or melting at the leading edge, followed by failure at the trailing edge. Once cooling air is lost at the airfoil due to failure, cooling air is also lost to downstream components, e.g., low pressure turbine vane, resulting in reduced life. Catastrophic vane failure can also create component failures downstream as fragments pass through low pressure turbine sections. There was also a Problem with the Engine's Bearings. The Problem was traced to close tolerance between the compressor fan blades and the stators (fixed blades). The DECS software at times delivered inappropriate commands. Problems with overheating were traced to the F402's inlet guide vanes, which suffered from contamination of the lubrication system. In the opinion of both the Navy and Rolls-Royce, fixing the clearance and guide-vane shortcomings would require "a major redesign".

 

 

Keep in mind that when the P.1127 came out in 1959, It only had 13000 Pounds of Thrust. 70 Versions of the Pegasus Engine have been Produced since. The TAV-8B Harrier II Plus built in 1990 produced a Thrust of 23,800 lbs.

[Hokum 0]

Ok done some testing. After patching.

GR.1 Can VTO (just) with 75% Fuel and 0% ammo.

 

GR.3 Can VTO with authority with 100% fuel and ammo (i didnt try this aircraft last night).

 

GR.7 Can VTO (JUST!) with 75% fuel and no weapons!

[+Crusader 2,102]

yep, and thats all correct. when they do VTO then they have only few internal fuel ( 50% and less).

the Falkland pics show all LANDING aircraft, TO was ALWAYS ( except on two occasions where 2 SHARs had to land on the Amphibs) via the "ski ramp" or normal short rolling takeoff on FOB Sheatbill.

when landing, external tanks were always empty and internal fuel low. Occasionaly GR.3's landed vertically with unexpended bombs, but had low internal fuel.

Also keep in mind that in the cold temps in the South Atlantic the engines could operate at their max thrust. Thats not possible in "hot and high" conditions, where vertical TO/LDG performance is more restricted.

 

AV-8A with " full combat load" ( say 4-5 mk82) has not much internal fuel

[+331Killerbee 840]

The Cool thing about working on Harriers over the Years is that You tend to collect things.....

 

One such Item is what I have in front of Me. It NavAir A1-AV8BB-NFM-000 15 September 2001 with Change 1 August 2004.

What it is, Is the Naval Flight Manual for the AV-8B published by NavAir. In Chapter 7...Actually Chapter7 4.2.7 States:

 

Water Injection Limitations. Distilled or demineralized water (per NAVAIR Instruction13780.1) must be used whenever possible.Repeated use of other than distilled or demineralizedwater results in deterioration of engine

performance. Water injection is not to be used if OAT is below −5°C.

 

4.2.8 Engine Bleed Limitations. More than 5 minutes of continuous engine bleed in hover flight is prohibited. Continuous hover flightmust be followed by a cooling period (forwardflight or ground operations) of the same duration.

 

These are the only Limitations to Hovers. Takeoff or Landing. Full Fuel and Full Weapons Load or Not.

 

I don't have a Copy of A1-AV8A/C-NFM. But I'm pretty sure It'll state the same thing. How do I know know they'll do it besides this........

 

I worked on Harriers 24/7 for 14 Years.......

 

 

331KillerBee

[+331Killerbee 840]

Reading this thing reminded of this. Each Harrier Unit in the USMC has a HPFOK. What is a HPFOK?

 

Hover Pad Foward Operating Kit. Put together, It's the size of a Tennis Court. For operating Foward with the Grunts. We used it in OPVAL at VX-5 and tested it for full operation. I do remember having a AV-8B with 4 300gal DropTanks full lifting off from the Pad durning one of the Tests. I loaded the Tanks.

[+331Killerbee 840]

This is how a HPFOK would work:

 

[Hokum 0]

Interesting KB, so my question stands, is the Harrier GR.1 underpowered in game? Also bob's GR.7 (not a crit of the plane it flies great) as the GR.3 can VTO with rockets in game!

I can live with STO but it would be nice to VTO if i want/need to.

 

 

Anyone else noticed that the engine (game) really has issues with the harrier when it comes to VL, i had a nice slow but steep approach. I was comming in at about 70kts and an angle of about 70 degrees. My speed dropped to 60kts and the harrier suddenly span on its Z axis 90 degrees with no rudder input! I was expecting some wallow not to be suddenly be pointing in the wrong direction! Then it flipped over on the X axis!

I'll see if i can repeat it and record it.

Edited June 23, 2009 by Hokum

[JediMaster 451]

When you're going that slow most sims have problem with the FM coding. You really need a good helo FM (which the TW sims don't yet have).

[Gr.Viper 131]

I don't get that yaw problem when I land like a helo. That is, speed and altitude must both decrease gradually so that the plane becomes really slow about 2m above the runway (not some 50m in the air, you won't be able to hover long enough to land). Then you throttle down and hit the brakes.

[+kreelin 2]

When you're going that slow most sims have problem with the FM coding. You really need a good helo FM (which the TW sims don't yet have).

 

I disagree You can have a "good" helo FM in TW sims. I never had problem to hover, little backward or any other helicopter figures..

 

As you can see here

 

http://www.dailymotion.com/user/_kreelin_/...trip_videogames

 

Of course it's not an Harrier...

[+Crusader 2,102]

The Cool thing about working on Harriers over the Years is that You tend to collect things.....

 

One such Item is what I have in front of Me. It NavAir A1-AV8BB-NFM-000 15 September 2001 with Change 1 August 2004.

What it is, Is the Naval Flight Manual for the AV-8B published by NavAir. In Chapter 7...Actually Chapter7 4.2.7 States:

 

Water Injection Limitations. Distilled or demineralized water (per NAVAIR Instruction13780.1) must be used whenever possible.Repeated use of other than distilled or demineralizedwater results in deterioration of engine

performance. Water injection is not to be used if OAT is below −5°C.

 

4.2.8 Engine Bleed Limitations. More than 5 minutes of continuous engine bleed in hover flight is prohibited. Continuous hover flightmust be followed by a cooling period (forwardflight or ground operations) of the same duration.

 

These are the only Limitations to Hovers. Takeoff or Landing. Full Fuel and Full Weapons Load or Not.

 

I don't have a Copy of A1-AV8A/C-NFM. But I'm pretty sure It'll state the same thing. How do I know know they'll do it besides this........

 

I worked on Harriers 24/7 for 14 Years.......

 

 

331KillerBee

 

 

Yup KB, thats cool.. but... ( regarding bold marked text)

 

if a Harrier can VTO or not is simply a thing of available thrust versus aircraft weight .

 

If you say you've seen a AV-8B taking off vertical with 4 300 gal tanks.. then the tank were not full.

 

An AV-8B in the late 80's with F402-RR-406 enige, max (wet) thrust 21.550 lb ( availabe only for a very short time) has a Operating Empty Weight of 13.068 lb ( OEW definition - wiki )

 

Full internal fuel ( JP-5, 6.8 lb per Gal. ) 1184 Gal = 7.915 lb

4x 300 Gal external tanks = 7.915 lb ( cant be filled to nominal 8.160 lb)

 

= 15.830 lb of fuel total

add this to the Operating Empty weight gives 28.916 lb of total weight.. versus max availabe thrust of 21.550 .

 

Vertical TO possible ? No Way. Even not with the latest engine which gives some 2500 lb more thrust... and the B+ also has a higher Operating Empty weight.

 

So to be able to take off vertical, the complete aircraft configuration ( whatever configuration, fuel, bombs, etc) must be always less than available power.

[Hokum 0]

If i read right total thrust must be at least in the ratio of 1.1-1.2/1 to achieve vertical take off.

 

So GR.1 Empty: 12,190 lb

Internal Fuel: 630.21 Gallons = 4285lb

 

Total = 16445lbs

 

Thrust of Rolls-Royce Pegasus 101 turbofan 19,000 lbf + 1,000 lbf from reaction stabilisers. = 1.21 to internal weight. So the GR.1 "should" be able to VTO with max internal fuel.

[FastCargo 412]

So if it doesn't, adjust the data.ini using those numbers and it should.

 

After playing around making the F-35B hover, I can tell you the physics to make it VTOL worked properly....I only used real world numbers and it VTOLs just like the real thing (with the same limitations).

 

FC