SRVL with the F35 and ‘bolters’
Thread Starter
SRVL with the F35 and ‘bolters’
I’ve read with interest the articles on the F35 and it’s initial tests on the QE carrier
The rolling low speed landing seems like a good idea, allowing more weapons and fuel to be brought back on board if they haven’t been used
I assume this is because, like the Harrier there’s a maximum hovering weight for a true vertical landing so a low speed approach and touch down using a combination of thrust vectoring and some wing lift gives you a little more performance margin
The last story I read stated they are also looking at a ‘bolter’ option for the SRVL and this is a bit puzzling
I don’t see how this is a realistic option, with a conventional carrier using an angled deck and arresting gear, on touchdown the pilot immediately selects full power and if a cable is not engaged he already has enough thrust and speed to lift off and go around again
How can this be an option with a rolling landing on the straight deck of the QE ?
On touchdown I assume the pilot will apply maximum braking, perhaps there’s a way to deflect some thrust forward as well ?
So, in this scenario the pilot touches down, does his best to stop but thinks he won’t be able to
Questions:
How does he know positively he won’t stop until it’s too late and he’s about to go off the deck ?
Do you paint a line on the flight deck ? If not on board by that point then go around ?
Surely that would vary, based on aircraft weight, wind over the deck ?
If you decide to ‘bolter’ how quickly can the aircraft be reconfigured for take off and would you have adequate performance to actually get airborne from what could be a very low speed ?
Does the pilot plan on lifting off before the ‘ski jump’ or utilizing it to help in getting airborne
Interested to see how this is being worked out
The rolling low speed landing seems like a good idea, allowing more weapons and fuel to be brought back on board if they haven’t been used
I assume this is because, like the Harrier there’s a maximum hovering weight for a true vertical landing so a low speed approach and touch down using a combination of thrust vectoring and some wing lift gives you a little more performance margin
The last story I read stated they are also looking at a ‘bolter’ option for the SRVL and this is a bit puzzling
I don’t see how this is a realistic option, with a conventional carrier using an angled deck and arresting gear, on touchdown the pilot immediately selects full power and if a cable is not engaged he already has enough thrust and speed to lift off and go around again
How can this be an option with a rolling landing on the straight deck of the QE ?
On touchdown I assume the pilot will apply maximum braking, perhaps there’s a way to deflect some thrust forward as well ?
So, in this scenario the pilot touches down, does his best to stop but thinks he won’t be able to
Questions:
How does he know positively he won’t stop until it’s too late and he’s about to go off the deck ?
Do you paint a line on the flight deck ? If not on board by that point then go around ?
Surely that would vary, based on aircraft weight, wind over the deck ?
If you decide to ‘bolter’ how quickly can the aircraft be reconfigured for take off and would you have adequate performance to actually get airborne from what could be a very low speed ?
Does the pilot plan on lifting off before the ‘ski jump’ or utilizing it to help in getting airborne
Interested to see how this is being worked out
Join Date: Dec 2006
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Stilton,
I might be able to help a little here, but I'm also very happy to defer to those on PPrune who will have more up to date knowledge of the F-35B SRVL development.
The SRVL has been developed to meet a specific UK requirement. It gives the aircraft the ability to land back on the ship at the specified 'Vertical Landing Bring Back' (VLBB) weight, but at higher temperatures and lower pressures than those specified by the US customers. It also, as you rightly say, gives the user the ability to get back on board at higher weights, which could be due to unused weapons, or fuel.
I've done a check on line and haven't found anything official in the last few years about looking at 'bolters'. I have found a number of questions about it on a number of forums, though. My last information on this (about 2 years ago) was that given the length of the QE flight deck, bolters weren't being looked at.
The SRVL gives more than a 'little more performance margin'. I've seen figures between 2,500 and 7,000 pounds additional bring back mentioned. My guess is around 4,000 pounds, but I could be wrong. As far as I know, no 'nozzle braking' is available on the F-35B - the thrust vectors available from the front fan and the rear nozzles are limited to 5 degrees forwards The Harrier had around ten degrees forward nozzle available, but that was mainly to give the aircraft the ability to go decelerate and go backwards in the hover. The F-35B can do this as well (up to 30 its backwards) using both the 5 degrees nozzle vectoring and differential thrust from the front fan and rear nozzle.
If bolters were required, remember that the aircraft is doing SRVLs in the same 'powered lift' configuration as is used for ramp takeoffs. I would hazard a guess (and that's all it is) that a bolter COULD be carried out by just trundling along the length of the flight deck and up the ski jump, setting the nozzle angles and spooling up the engine. Speed shouldn't be a problem, as the aircraft is landing at lower weights than for a normal ramp launch, and it should be going faster than normal as it reaches the start of a normal ramp take off. As to any 'need a bolter' line, that would have to adjusted to reflect the aircraft landing weight and other factors. But to repeat, I don't think that the UK are looking at this. And I could well be wrong here.
Any PPruners with more current knowledge out there?
Best regards as ever to the team who have done such a great job with the recent QE F-35B trials. Making tough stuff look easy is the mark of true professionals.That's what they are. BZ.
Engines
I might be able to help a little here, but I'm also very happy to defer to those on PPrune who will have more up to date knowledge of the F-35B SRVL development.
The SRVL has been developed to meet a specific UK requirement. It gives the aircraft the ability to land back on the ship at the specified 'Vertical Landing Bring Back' (VLBB) weight, but at higher temperatures and lower pressures than those specified by the US customers. It also, as you rightly say, gives the user the ability to get back on board at higher weights, which could be due to unused weapons, or fuel.
I've done a check on line and haven't found anything official in the last few years about looking at 'bolters'. I have found a number of questions about it on a number of forums, though. My last information on this (about 2 years ago) was that given the length of the QE flight deck, bolters weren't being looked at.
The SRVL gives more than a 'little more performance margin'. I've seen figures between 2,500 and 7,000 pounds additional bring back mentioned. My guess is around 4,000 pounds, but I could be wrong. As far as I know, no 'nozzle braking' is available on the F-35B - the thrust vectors available from the front fan and the rear nozzles are limited to 5 degrees forwards The Harrier had around ten degrees forward nozzle available, but that was mainly to give the aircraft the ability to go decelerate and go backwards in the hover. The F-35B can do this as well (up to 30 its backwards) using both the 5 degrees nozzle vectoring and differential thrust from the front fan and rear nozzle.
If bolters were required, remember that the aircraft is doing SRVLs in the same 'powered lift' configuration as is used for ramp takeoffs. I would hazard a guess (and that's all it is) that a bolter COULD be carried out by just trundling along the length of the flight deck and up the ski jump, setting the nozzle angles and spooling up the engine. Speed shouldn't be a problem, as the aircraft is landing at lower weights than for a normal ramp launch, and it should be going faster than normal as it reaches the start of a normal ramp take off. As to any 'need a bolter' line, that would have to adjusted to reflect the aircraft landing weight and other factors. But to repeat, I don't think that the UK are looking at this. And I could well be wrong here.
Any PPruners with more current knowledge out there?
Best regards as ever to the team who have done such a great job with the recent QE F-35B trials. Making tough stuff look easy is the mark of true professionals.That's what they are. BZ.
Engines
Last edited by Engines; 6th Dec 2018 at 09:38. Reason: Updated info
