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The Eurofighter Typhoon has an interesting "feature" in that the nose gear door is shorter than the nose gear bay itself by a good few inches, as shown here:

Eurofighter Typhoon Nose Gear Bay

Can anyone shed any light on the reason for this gap? It isn't a simple case of the aircraft in the photo having a maintenance issue, as this gap is consistent across all aircraft tranches and customers.

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    $\begingroup$ Maybe a budget cut? $\endgroup$ – vasin1987 Nov 27 '15 at 12:00
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    $\begingroup$ Uh oh, looks like someone mixed up metres and yards again! $\endgroup$ – Jamiec Nov 27 '15 at 14:04
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    $\begingroup$ True, maybe its where the chemtrail exhaust is located $\endgroup$ – Jamiec Nov 27 '15 at 14:39
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    $\begingroup$ @SMSvonderTann Some say it is APU. Really? Where? People who don't know aircraft design? $\endgroup$ – Simon Nov 27 '15 at 20:08
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    $\begingroup$ Ventilation for the gear bay? $\endgroup$ – Gürkan Çetin Dec 1 '15 at 19:52
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enter image description here
(primeportal.net) Click for the full unedited image

There is indeed a gap as shown in the above close-up taken in a museum. But it's not for an APU as rumored. It could have been cut short to accommodate those tiny pipes (hydraulic lines?). Some (not all) F/A-18's have a similar gap as well:

enter image description here
(wikimedia.org) RAAF F/A-18A Hornet

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  • $\begingroup$ That seems reasonable, but this gap doesn't seem to appear on other fighter aircraft with similar performance characteristics. Good on ya' for hunting down a possible answer to an old, unanswered question! $\endgroup$ – FreeMan Jun 7 '16 at 16:02
  • $\begingroup$ I doubt this. The pipes are inside and don't need any opening, so there is no observable reason why they could not be covered by the gear door when they close. $\endgroup$ – Jan Hudec May 19 '18 at 20:56
  • $\begingroup$ @JanHudec - My reasoning accounts for some door thickness -- I also had another theory in an early revision: You don't want a rapid climb to force open the gear door (differential pressure if it's an air-tight-kind-of-seal). @ Alex's answer is more elegant though. $\endgroup$ – ymb1 May 20 '18 at 0:55
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Some fighters and as well civil airliners have fans ending in the gear bay. To allow for pressure relief some sort of opening needs to be created to vent to atmosphere. Various designs are available to achieve this, like the well known grills or mesh on carbon or aluminum structure skin. Or, just shorten a nose gear bay door if you have no place to accommodate the mesh and suck it through top part (see holes in the top where cables is routed) If you stick your head into a F18 nose gear bay and it is electrically powered, it will be quite noisy. Seems as the Eurofighters have the same design.

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  • $\begingroup$ A video of the Super Hornet's gear swing and a picture of the Super Hornet's underside seems to support your answer. Specifically, a mesh is visible in the nose gear door in the video, and the picture does not show the same gap present in ymb1's Hornet picture. $\endgroup$ – aerobot Dec 12 '17 at 2:03
  • $\begingroup$ @aerobot - the mesh is farther ahead, same mesh on the F/A-18 in my answer. I guess that's the avionics bay ventilation. $\endgroup$ – ymb1 May 19 '18 at 14:51
  • $\begingroup$ @ymb1 - are we looking at the same mesh? In the video and picture I linked, the mesh is longitudinal (on the strut portion of the gear door), which is definitely not present in the F/A-18A Hornet picture in your answer, unless I'm missing somethIng. $\endgroup$ – aerobot May 19 '18 at 18:45
  • $\begingroup$ @aerobot - I see what you mean now, makes sense. $\endgroup$ – ymb1 May 20 '18 at 0:48
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Could it also be a vent for tire smoke? Most Nose Gears do not have brakes and therefore utilize some form of fixed resistance pad inside the gear bay to spin down the wheel, since this generates heat and smoke the opening could assist in venting this effect.

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