Harrier transition to and from hover

[Engines]

Gents,

JF may well correct me, but I believe that the key aspect of a Harrier CTO is that it had a bicycle undercarriage layout, with the aircraft weight spread nearly 50/50 between the main and nose legs. In truth, the 'nose' leg was really a 'front main'. What that meant was that the Harrier couldn't really rotate about the aft main leg. Bicycle gear was very popular on jets in the 40s and 50s, see also B-47, B-52, Vautour. It was useful on the Harrier as it kept the main wheels away from the hot nozzle wash. (Again, so I've been told)

I have also been told that the undercarriage was modified during development to give the wing a higher incidence to make CTOs (and conventional landings) slightly easier and to shorten the TO run.

Main wheel location (on normal tricycle layouts) is driven by lots of things, including ground stability as well as takeoff and landing loads and dynamics. For naval aircraft, there also have to be margins for aircraft moving backwards on a rolling deck, as well as the peculiarities of cat and trap ops.

On F-35, the main legs are actually located outboard of the weapons bays, their fore and aft location was mainly driven by structural aspects. However, during the weight saving effort, the main legs were raked forward to reduce the control loads required for CTOL (and STOVL) variant rotation during takeoff.

It should also be noted that the F-35B nose leg takes only about 10% of the static load, compared with the 50% of the Harrier. Many of us on the programme were surprised at the 'spindly' look of the nose gear, but that was just a result of our own ignorance. It's actually a tough little mother.

Hope this helps, interesting thread (until this post, that is)

Best Regards as ever

Engines