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-   -   Lightning (https://www.pprune.org/military-aviation/621944-lightning.html)

NutLoose 27th May 2019 11:15

Lightning
 
At Bruntingthorpe for those that missed it.

https://live.staticflickr.com/65535/...4fda2b0c_c.jpg
Smile please.. by Tony Taylor, on Flickr

https://live.staticflickr.com/65535/...9c35d10a_c.jpg
Lightning Run by Tony Taylor, on Flickr

https://live.staticflickr.com/65535/...1446c8f6_c.jpg
Lightning Run 2 by Tony Taylor, on Flickr

https://live.staticflickr.com/65535/...3d568b5b_c.jpg
Lightning return by Tony Taylor, on Flickr


https://live.staticflickr.com/65535/...b79ee056_c.jpg
Lightning open canopy by Tony Taylor, on Flickr

sherriff 27th May 2019 12:25

Oh yes ! Was there. Ears are still ringing from that run.
It was worth going, just for that.
Unforgettable.

Kiltrash 27th May 2019 14:25

Pardon. Bit noisy was it ...

Shaft109 27th May 2019 14:38

I was surprised how loud the bangs were when the reheats engaged.

A great day and well worth the trip down, but didn't get to see the Victor fly - unlike last time lol.

newt 27th May 2019 20:13

It was a very good day and almost brought a tear to the eye! Great effort by all the guys who look after these aircraft!

sandiego89 28th May 2019 16:58

Thank you for posting. Would really love to get there someday.

Why do the first three photos look like there is a plug in the intake? Is that condensation under certain atmospheric conditions/engine RPM? Common?

dook 28th May 2019 17:13

The bangs upon engaging burner could be heard in the cockpit but nowhere near as loud.

topgas 28th May 2019 19:50

The video doesn't do justice to the volume of low frequency noise which just resonates through your whole body. Fantastic day, with the VC10, Comet, Beluga and Shack all open to visit the cockpit. Unfortunately couldn't stay to see the Victor do its run.

NutLoose 28th May 2019 21:57


Originally Posted by sandiego89 (Post 10481467)
Thank you for posting. Would really love to get there someday.

Why do the first three photos look like there is a plug in the intake? Is that condensation under certain atmospheric conditions/engine RPM? Common?

Yes, the thing was in reheat at the time.

CoodaShooda 28th May 2019 22:00

I had the opportunity to sit in the Lightning cockpit at Tangmere this week.

I quickly realised that that it was not designed for oversized colonials. It was tighter than the SE5 mock up they have.

Such a small office for such a large airframe. My respect to those of you who mastered her.

NutLoose 28th May 2019 22:17

https://live.staticflickr.com/65535/...d7355ab8_c.jpg
Showing the crowd his watch by Tony Taylor, on Flickr

https://live.staticflickr.com/65535/...243faec8_c.jpg
Lightning thumbs up by Tony Taylor, on Flickr

GeeRam 29th May 2019 08:08


Originally Posted by sandiego89 (Post 10481467)
Why do the first three photos look like there is a plug in the intake? Is that condensation under certain atmospheric conditions/engine RPM? Common?

I remember it being very evident in that fabulous head-on shot taken by IB of a F.6 take-off from Binbrook......and it took me a while to find it online :)

https://cimg6.ibsrv.net/gimg/pprune....96945f378d.jpg

dook 29th May 2019 18:29

The "condensation" in the intake is simply explained.

The radar bullet forms a convergent duct initially. This results in flow acceleration which causes a drop in pressure and therefore a drop in temperature.

When the relative humidity is high this temperature drop causes saturation and thus visible moisture. Seemples.

ORAC 29th May 2019 19:47

https://www.skytamer.com/English_Ele...tning_F.6.html

“Supersonic speeds also threatened inlet stability; the inlet's central shock cone served as a compression surface, diverting air into the annular inlet. As the “Lightning” accelerated through Mach 1, the shock cone generated an oblique shock positioned forward of the intake lip; known as a subcritical inlet condition, this is stable but also produces inefficient spillage drag. Around the Design Mach speed, the oblique shock is positioned just in front of the inlet lip and efficiently compressed the air without any spillage. As speed increases beyond Design Mach, the oblique shock becomes supercritical, where supersonic airflow enters the inlet duct. The “Lightning's” inlet was designed to handle only subsonic air, a supercritical state not only drastically reduced engine thrust output but could lead to surges or a compressor stall, which could result in engine flameout and/or damage.

Thermal and structural limits were also present; as air is heated up when compressed by the passage of an aircraft. This heating increases considerably when at supersonic speeds. The airframe absorbs heat from the surrounding air, the inlet shock cone at the front of the aircraft becoming the hottest part. The shock cone was composed of fiberglass, necessary because the shock cone also served as a radar radome; a metal shock cone would interfere with the AI 23's radar emissions. The shock cone would be eventually weakened due to the fatigue caused by the thermal cycles involved in regularly performing high-speed flights. At 36,000 ft and Mach 1.7, the heating conditions on the shock cone would be similar to those at Sea Level and 650 KIAS, but if the speed was increased to Mach 2.0 at 36,000 ft, the shock cone would be exposed to temperatures more than 70% higher than those at Mach 1.7. The shock cone was strengthened on the later “Lightning” F.2A, F.3, F.6, and F.53 models, thus allowing routine operations at up to Mach 2.0.”.....

dook 29th May 2019 19:55

Yes - I know, having flown it for five years.

That's not what the question was about though.

Is the web your friend ?=left

=leftSupersonic speeds also threatened inlet stability. The inlet's central shock cone served as a compression surface, diverting air into the annular inlet. As the Lightning accelerated through Mach 1, the shock cone generated an oblique shock positioned forward of the intake lip. Known as a subcritical inlet condition, this was stable, but produced inefficient spillage drag. Around the Design Mach speed, the oblique shock was positioned just forward of the inlet lip and efficiently compressed the air without spillage. When travelling beyond the Design Mach, the oblique shock would become supercritical, and supersonic airflow would enter the inlet duct, which could only handle subsonic air. In this condition, the engine generated drastically less thrust and may result in surges or compressor stalls, these could cause flameouts or damage.=leftThermal and structural limits were also present. Air is heated considerably when compressed by the passage of an aircraft at supersonic speeds. The airframe absorbs heat from the surrounding air, the inlet shock cone at the front of the aircraft becoming the hottest part. The shock cone was composed of fibreglass, necessary because the shock cone also served as a radar radome; a metal shock cone would interfere with the AI 23's radar emissions. The shock cone would be eventually weakened due to the fatigue caused by the thermal cycles involved in regularly performing high-speed flights. At 36,000 feet (11,000 m) and Mach 1.7 (1,815 km/h), the heating conditions on the shock cone would be similar to those at sea level and 650 knots (1,200 km/h) indicated airspeed,[nb 8] but if the speed was increased to Mach 2.0 (2,136 km/h) at 36,000 feet (11,000 m), the shock cone would be exposed to higher temperatures[nb 9] than those at Mach 1.7. The shock cone was strengthened on the later Lightning F.2A, F.3, F.6, and F.53 models, thus allowing routine operations at up to Mach 2.0.[85]

sandiego89 29th May 2019 20:03

Thank you everyone for the explanation and that is a cracking picture GeeRam, and good piece on the inlet design ORAC- Lightning aerodynamics and design peculiarities are always a great topic of banter.

NutLoose 29th May 2019 22:59


The “Lightning's” inlet was designed to handle only subsonic air
because the air flowing through a gas turbine engine needs to be subsonic regardless of what speed the aircraft is travelling at..


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