F-35 Canopy vs F-22 Canopy

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spazsinbad

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Unread post11 Feb 2021, 20:48

XanderCrews wrote:Great and thorough post, Magitsu [double thanks for great post]
Yep on the det cord, something carried over form the Harrier. if the airplane is in a hover and starts to "fall" There is ZERO airspeed to move the canopy out of the way and clear of the seat(s) moreover, you're ejecting from an airplane that is low to the ground (little time) and actually dropping (bizarre/unique scenario) the parachute has a special "canopy opener" and some other unique features as well.

NOT ONLY THAT BUT ALSO there is an extremely fast F-35B rotation noted in other threads I need to find - out in 0.6 sec. This is specially handled in the F-35B MB ejection seat automatically. The function kicks in when aircraft in STOVL mode.
Test Flying The Joint Strike Fighter
17 June 2011 Graham Tomlinson

“...In the unlikely event of the lift fan failing catastrophically the aircraft would pitch inverted in 0.6 seconds, and the pilot is protected by auto-ejection signalled by pitch rate and attitude (derived from the YAK 38 & 141 systems)....”

Source: http://myweb.tiscali.co.uk/hawkerassoci ... ghter.html

Synopsis of Lecture to RAeS Loughborough Branch - Martin-Baker: the JSF story so far
08 Mar 2011 Steve Roberts, JSG IPT Lead, Martin-Baker Aircraft Company Ltd

“...The ejection seat was required to be common to all three aircraft variants. It was also required to have superior ejection performance to all previous seats, meet new neck injury criteria and provide an auto-ejection capability when used in the F-35B (STOVL) aircraft. The last requirement demanded early firing of the ejection seat in the event of an aircraft malfunction in a manner similar to that used in the Russian YAK 36, 38 and 141 aircraft....

...Neck protection is provided by means of a “Catcher’s Mitt” inflatable device which supports both sides of the pilot’s helmet and also provides support to the top and /back of the helmet. This device is also held in a container located behind the pilot’s head. The device is vented before the parachute is deployed. The device has been tested & proved to inflate under simulated 50,000 ft altitude conditions....

...The F-35-B (STOVL) aircraft has additional failure modes associated with Lift Fan, Vane Box, Lift Fan Drive Shaft, Roll Duct and Turbine failures. A typical pilot takes two seconds to react to the ejection klaxon or one second if warned in advance of a likely failure. In the case of a STOVL related failure, ejection must take place within 0.6 seconds. Hence it was necessary to install smart failure sensors on the aircraft to automatically fire the ejection circuit mounted in the back of the seat....”

Source: http://homepage.ntlworld.com/john.oller ... 20seat.pdf
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hornetfinn

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Unread post12 Feb 2021, 12:25

spazsinbad wrote:
Test Flying The Joint Strike Fighter
17 June 2011 Graham Tomlinson

“...In the unlikely event of the lift fan failing catastrophically the aircraft would pitch inverted in 0.6 seconds, and the pilot is protected by auto-ejection signalled by pitch rate and attitude (derived from the YAK 38 & 141 systems)....”

Source: http://myweb.tiscali.co.uk/hawkerassoci ... ghter.html

Synopsis of Lecture to RAeS Loughborough Branch - Martin-Baker: the JSF story so far
08 Mar 2011 Steve Roberts, JSG IPT Lead, Martin-Baker Aircraft Company Ltd

“...The ejection seat was required to be common to all three aircraft variants. It was also required to have superior ejection performance to all previous seats, meet new neck injury criteria and provide an auto-ejection capability when used in the F-35B (STOVL) aircraft. The last requirement demanded early firing of the ejection seat in the event of an aircraft malfunction in a manner similar to that used in the Russian YAK 36, 38 and 141 aircraft....

Source: http://homepage.ntlworld.com/john.oller ... 20seat.pdf


Whatever the problems and flaws they might have, I have to say that Soviets and Russians (Zvezda company) designed some seriously good ejection seats. Everybody knows K-36 which has had some pretty spectacular airshow performances with Su-27 and MiG-29. That auto eject system in Yak-38 and -141 was also pretty damn innovative.

K-36D deep avaluation done by USAF Armstrong Laboratory: https://apps.dtic.mil/dtic/tr/fulltext/u2/a321294.pdf

This is what I found about Russian solutions for canopy coating: https://www.defenseworld.net/news/24049#.YCZk2ugzaUk

A new coating applied to the glass canopy of Russia’s Su-57 stealth fighter jet and the Tu-160 strategic bomber will cut down the radar cross-section of the aircraft by up to 30%.

The glass coating developed by specialists of the Obninsk-based Technologiya R&D Enterprise (part of RT Chemcomposite Group within Rostec) is made of metal oxide layers 70-90 nm thick. In addition to reducing visibility to enemy radars, it protects the pilot during the flight from the impact of ultraviolet, thermal and other negative factors, Russia’s state-run Rostec Corporation was quoted as saying by TASS on Friday.

"It doubles radar wave absorption and reduces the aircraft cockpit’s radar signature by 30% Currently, the coating is applied to the canopy of T-50 (Su-57 aircraft since August 2017), Su-30, Su-34, Su-35, MiG-29K and Tu-160 planes," Rostec said.

"The coating weakens the thermal component of solar radiation by more than three times while the integral transmittance index in the visible range makes up no less than 65% and the impact of the ultraviolet component drops by more than 4-6 times," the corporation said.

As Rostec Industrial Director for the Cluster of Conventional Armament, Ammunition and Special Chemistry Sergei Abramov said earlier, this innovation helps halve the weight of the cockpit’s glass canopy and increase impact resistance and radar wave absorption from 40% to 80%.


I find the numbers they present very interesting.
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spazsinbad

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Unread post12 Feb 2021, 14:21

Did anyone mention an ongoing problem with the outside coating of F-35 canopy which is perhaps being solved by now.
F-35 still hobbled by spares shortage [PDF of OLD article attached]
12-18 Nov 2019 GARRETT REIM

"...“We are particularly having issues in three different areas: one is canopies, two is engine fuel hydraulic tubes, and the other is wing-tip lenses,” says Ellen Lord, undersecretary of defense for acquisition and sustainment.

The issue with the canopies is concerned with the loss of the coating that is applied to the outside,” says Fick. “We’re working to mitigate that alongside the prime contractor Lockheed, and its subs GKN [Aerospace] and PPG [Industries].”..."

Source: Flight International Magazine 12-18 November 2019

US stealth fighters fail availability test [PDF of OLD article attached]
23-29 Jul 2019 Garrett Reim

"...“Transparency [canopy] supply shortages continue to be the main obstacle to achieving this,” he says. “We are seeking additional sources to fix unserviceable canopies.”

Lockheed has previously told FlightGlobal that canopies were one of the stealth aircraft’s trouble spots, resulting in higher operating costs...."

Source: Flight International Magazine 23-29 July 2019
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XanderCrews

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Unread post12 Feb 2021, 15:09

hornetfinn wrote: Everybody knows K-36 which has had some pretty spectacular airshow performances


Image

Auto ejects on Yaks makes sense as they have multi-engine style STOVL. If one engine fails its cartwheel time like Spaz describes F-35B has the protentional to do should one end of its STOVL system fail.

when a Harrier has an engine failure it fails all at the same time and generally keeps the same aircraft attitude and "pancakes" flat.
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steve2267

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Unread post14 Feb 2021, 17:06

If memory serves, the original canopy design for the F-35 was for a single piece polycarbonate canopy ala F-16 / F-22. Then the weight issues begat the SWAT weight reduction initiative. I want to say one of the results of SWAT was the single-piece, forward hinged, acrylic canopy: acrylic design is lighter than a similar polycarbonate canopy, and forward hinged was also lighter. But the acrylic design required the canopy bow to survive the bird strike requirements. But my memory may be faulty.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post14 Feb 2021, 17:23

Forward hinge also allows removal of the ejection seat for maintenance without removing the canopy; major benefit in ‘maintainability.’
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