AV-8B Harrier nozzle control up side down?
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Hello all,
at the moment I build my homepit, so I haven’t much time to fly. I’ve downloaded 4.33 before the s*** happend, but the cockpit building eats up all my free time. So all my experience about the AV-8B are youtube videos. I’ve build a nozzle control in my pit after some pics of real harrier controls, which have 0 degrees of nozzle full forward and 120 degrees full backward. In the videos of BMS on youtube I’ve seen that the 0 degrees are full back and 120 degrees full forward.
Is this a bug in BMS, or does different type of AV-8B controls exist?
P.S: The Razbam Harrier for FSX has the controls like the real controls I’ve seen (120 degrees full back)
THX Sven
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The short takeoff stop is rear of the handle so it makes sense that lever aft is nozzles down and lever forward is forward flight.
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Yes, that’s the way my nozzle controller in the cockpit is built. I’ve built the short takeoff stop selector too. The Razbam Harrier has the same controls, but in the videos of BMS on youtube I’ve seen, the lever full aft is flight. Correct me if I’m wrong.
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…I think they are wrong, not you. Here is a picture of a real Harrier throttle quadrant - note the smaller numbers on the nozzle lever are at the front…meaning nozzles aft. And the larger numbers are at the rear…meaning nozzles down.
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The NAVOPS manual didn’t have the scale text printed in the diagram, or at least not on the ones I saw skimming through. I didn’t need to have the scale to figure out the throw direction. Clearly the short takeoff stop is set at a nozzle position for the “jump” at the end of the horizontal takeoff run. The pilot accelerates at zero nozzle angle and at a painted line shifts the nozzles to the pre-selected stop to transition to flight.
Doing the nozzle lever motion backward in another variant would require this whole arrangement to be reversed with the stop on the other side of the lever and the linkages reversed for what lever angle equated to what nozzle angle. Stranger things have happened in aviation development but I’d put it at long odds. A fair bit of reengineering would have to go on to change something that presumably worked just fine to say nothing about pilot habits built under one model transitioning to a reversed control. Also “forward = forward motion” seems the most intuitive.
This BMS video certainly shows nozzle markings increasing aft. The lever appears to animate incorrectly:
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…having also spent a few years operating RL Harriers I can tell you that you are partially correct (and that the checklist and start sequence in this video are pretty out to lunch; BTW - the jet is taxied with nozzles down 10 to prevent buffeting the stabs…and 2 degrees ND trim to close the front puffer to avoid blowing FOD up off the ramp during taxi; I could write a paragraph on all of the things that are wrong in this video, but it a Viper sim and not a Harrier sim…).
Yes - the throttle quadrant is basically the same in all variants, though the throttle lever itself may vary. The STO stop (which you can actually raise and position on either side of the nozzle lever for RVTO, RVL, etc.) is actually positioned based on takeoff gross weight and airspeed requirements - not by a mark on the ramp or deck; nozzles are moved to STO position once takeoff airspeed is achieved, and a rolling takeoff is generally performed with nozzles full aft (and NWS disengaged). You’re correct about the ergonomics - lever fwd -> nozzles aft…or “up”, like flaps.
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Interesting to know about the RCS FOD thing. I mean you move the nozzles to the stop at the mark on the deck, not the particular nozzle angle you choose. I’m surprised to hear that the stop can be placed ahead of the lever too. How is it used in that configuration? Presumably you’re at a higher nozzle angle and need to hit that lower nozzle angle reliably; using the nozzles for braking and then resuming a position for actual letdown?
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You set the stop during startup in the chocks, and move the nozzles to the stop at a charted airspeed - which is dependent on takeoff gross weight - during the takeoff roll when you hit that airspeed. Think about the nozzles as a similar control as flaps - and that lowering nozzles generates a very strong pitching moment just like lowering flaps (but much greater) which you need to learn to tuck the nose to counter. If you are doing a rolling landing you may not want more than a specific nozzle angle (prior to braking) and so you’d set the stop to that angle, again based on field length and gross weight at landing. Tracking operating weight and lateral asymmetry are high pri for Harrier operators. If I recall correctly, you can also lift the handle to override the stop so you can go to braking during rollout…there’s more than one way to skin this cat…but you’d never go to the braking stop wingborn - i.e.; up and away. Flight regimes are broken down as “wingborn” in forward flight and “jetborn” in hover or in any situation where an appreciable amount of lift is being generated by nozzles.
But the main thing to know is that in the takeoff/landing pattern the application of nozzles is more like using flaps, and VSTOL operation similar to a helo in that GW and temperature of the day are the main factors affecting just what you can do and when…in some cases the engine will be speed limited (cold day), in others temp limited (hot day) - and then how much water you have remaining may dictate what you can do and for how long. And on some hot-hot days you just plain may not be able to hover at all, so you need to plan accordingly.
That’s one of the things we seem to be unburdened by with the Viper - I haven’t been able to find a max landing weight for the Viper, so I assume it can bring back anything it can take off with. Not the case for Navy/Marine ops. Bringback has to be strictly planned in accord with conditions/facilities.
May the bridges I burn light the way
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Iirc you have to lift over the STO stop when going nozzles down and can push over the STO stop when going nozzles aft. The surfaces are beveled going one direction and angled the other. There is a plate that has a screw in it that is adjusted to stop the lever near 90 called hover stop and you have to lift up to go more than 90. The lever has a spring on it in the throttle quad iirc. I noticed the harrier in BMS doesn’t have the engine performance panel. Also, The water switch is not there and is instead a hook switch. In the harrier the engine performance panel is really important because it is a one stop shop for the most important readings, especially when in a hover. When turning up the harrier you get in a habit of looking at the engine performance panel and although I haven’t messed with it in BMS I think it would be strange to be in the harrier and resist that habit. We look at that panel more than anything else. That is why it’s placed so close to the HUD. Is water modeled in BMS?
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I’m still confused when one would limit how small a nozzle angle one would use by putting the stop on the forward side of the lever. I am at some high nozzle angle (lever aft) and push the lever forward to the stop. When would I do that?
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I have never heard of or seen it done and can’t think of any reason, but that doesn’t mean it doesn’t happen. The reality of it is that the STO stop is used to stop the nozzles from going too far down. When going nozzles aft the lever will slide over the sto stop. The only time the sto stop is on the forward side of the lever is after you have moved the lever behind the sto stop. It’s not so much as the sto stop being placed in front of the lever as the lever being placed behind the sto stop during nozzle rotation. Like I mentioned, I don’t think the sto stop is ever primarily used to limit the nozzles going aft. The sto stop is mostly used as an indicator. You set it at a spot and you know you’re there when you hit it. Different sto stop settings are used for different purposes. It’s really easy to changed the sto stop and is often done in flight if STO or VL is done.
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OK, I think I get it. The fact that the lever can be on either side of the stop doesn’t mean it’s being used as a stop from both directions.
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I’m still confused when one would limit how small a nozzle angle one would use by putting the stop on the forward side of the lever. I am at some high nozzle angle (lever aft) and push the lever forward to the stop. When would I do that?
RVL…Rolling Vertical Landing, or SL - Slow Landing. Again, you have to think of the nozzles like flaps - in that case you only want “so much” or “not less than”, and again that’s dependent on gross weight; think - too heavy for hover, field too short for CL (Conventional Landing) rollout. Once again, pre-planed prior to getting into the jet. I can’t stress how important gross weight is to VSTOL operations enough.
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Iirc you have to lift over the STO stop when going nozzles down and can push over the STO stop when going nozzles aft. The surfaces are beveled going one direction and angled the other. There is a plate that has a screw in it that is adjusted to stop the lever near 90 called hover stop and you have to lift up to go more than 90. The lever has a spring on it in the throttle quad iirc. I noticed the harrier in BMS doesn’t have the engine performance panel. Also, The water switch is not there and is instead a hook switch. In the harrier the engine performance panel is really important because it is a one stop shop for the most important readings, especially when in a hover. When turning up the harrier you get in a habit of looking at the engine performance panel and although I haven’t messed with it in BMS I think it would be strange to be in the harrier and resist that habit. We look at that panel more than anything else. That is why it’s placed so close to the HUD. Is water modeled in BMS?
I haven’t looked, but I doubt the VSTOL Master Mode HUD presentation is modeled either. There’s also some engine stuff in the HUD in VSTOL MM. As I recall the STO stop generally got moved out of the way during climbout (nozzles “free”) and positioned for landing on the downwind, but that may well be pilot preference in cockpit discipline.
What “my guys” used to tell me was that once they were up and away - “throttle goes into the corner, and feet go flat on the floor”. I once got the opportunity to fly the Night Attack Harrier trainer at MCAS Yuma and found that once I got over my initial mistakes with the nozzles (after I nearly lost the jet “slaming” them around too hard) that this was exactly how I ended up flying…I never touched/changed the power unless I was in the landing pattern, and controlled speed with my nose for the most part, zooming around at 200 AGL. The operators were pretty impressed by my CL skills - which they told me is actually the hardest way to land the airplane…I wasn’t interested in touching that nozzle lever again, so I was just doing what I know how to do!
May the bridges I burn light the way
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Oh started some big discussion
Yes Frederf, that’s exactly the video I’ve seen on youtube. And Stevie, that’s the picture I built my nozzle-control after. I was really shocked to see that the nozzle control in BMS works opposed, after a few hours of building my throttle console. But it seems to be wrong in BMS. Something for the todo-list if a new update appears
Hope that new updates will appear, since the current situation makes me very nervous about the future of BMS. -
As I recall the STO stop generally got moved out of the way during climbout (nozzles “free”) and positioned for landing on the downwind, but that may well be pilot preference in cockpit discipline.
Yeah, the STO stop was usually not used unless on the boat or training for the boat. Most of the time in the states we worked on weapons systems and wing lifted quals. When we would get close to a deployment we would start to see STO and vertical landings. Then we would go to Bogue field where they practice landings and TO’s with a representation of a flight deck painted on the ground. There is also a tower like the one on the boat so they can get qualified to direct the harrier’s landing on the boat and grade their landings. From what I know the STO was used just for STOs and sometimes slow rolling landings and mostly on the boat. As you know it can be moved all the way aft so that it is out of the way.
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I haven’t looked, but I doubt the VSTOL Master Mode HUD presentation is modeled either.
It would be cool to have the JPT and H2O modeled. Having to pay attention to water consumption and JPT and having the exhaust turn black when water is on would be great.
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Yeah, the STO stop was usually not used unless on the boat or training for the boat. Most of the time in the states we worked on weapons systems and wing lifted quals. When we would get close to a deployment we would start to see STO and vertical landings. Then we would go to Bogue field where they practice landings and TO’s with a representation of a flight deck painted on the ground. There is also a tower like the one on the boat so they can get qualified to direct the harrier’s landing on the boat and grade their landings. From what I know the STO was used just for STOs and sometimes slow rolling landings and mostly on the boat. As you know it can be moved all the way aft so that it is out of the way.
I think because of the elevation and takeoff weights we were operating at doing nozzle assisted takeoffs were pretty routine. Or maybe I should say density altitude…being a desert operator we were hot and high. There’s (was?) a practice deck down in Yuma someplace that folks could shoot, but most of what I was involved with had the jets pretty loaded and so nozzle assist was routine, vertical ops were generally reserved for winchester RTB or maintenance press-ups. Lots of SLs, RVL, CLs otherwise.
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It would be cool to have the JPT and H2O modeled. Having to pay attention to water consumption and JPT and having the exhaust turn black when water is on would be great.
…and engine over temp. That - and blowing your tires for not getting off the hot spot in short order, or spending too much time in the hover - seen that. In fact, I’ve seen that happen a fair time post landing, but only once…jet came in, brake checked, chocked. Later post-shutdown a Maintainer was heading up a ladder with a replacement HUD over his shoulder when the main tires just up and blew. Never really got an explanation as to how that could have happened.
May the bridges I burn light the way
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Never really got an explanation as to how that could have happened.
Yeah. blowing the mains often gets the face palm. It happens a lot to new pilots and turn quals when they are on the ground with the nozzles down. When we certify a new low power we always tell them that they can only have nozzles down for a few minutes, then they need to go aft to cool the mains down. At about 10 degrees is the sweet spot to blow the LP cool air onto the mains after getting them hot. I remember seeing some dumb ass looks on people’s faces when they went low rider from blowing the mains. Most of the time they would either go out there and help change the mains or buy the guys some beer and pizza. The MLG tires on a harrier have safety valves in them filled with a wax/plastic like substance that melts a bit before the tire explodes or the rubber tire melts. So that is what you’re seeing when the tires go flat without a pop or a hole in the tire. Even though the tires are filled with nitrogen they can get so hot that they will explode. The force those tires have when they explode is not safe in any way. Some of the crusty old guys told me the tire doesn’t fail, the rim does and can send parts of the metal rim flying for hundreds of feet with enough force to kill someone. That is why they put the safety valves with a wax like substance in it.
