IN UNDER FIVE PARSECS: Stormtrooper Jacob French on day five of his over 4000 kilometre journey from Perth to Sydney.

There are many obvious disadvantages to walking across Australia wearing full Imperial Stormtrooper garb. But on the bright side, at least Jacob French is unlikely to suffer sunburn as he treks solo across the Nullarbor from Perth to Sydney to raise A$50,000 for the Starlight Children's Foundation.

''I have always had this dream to walk across Australia and I thought if I was going to put that much effort into something which would make me happy, I might as well make other people happy on the way,'' the Perth sales assistant said. ''I thought I might as well give people a bit of a chuckle at the same time by doing it in a Stormtrooper suit.''

Mr French, 20, started his ''Troopertrek'' on Monday and aims to arrive in Sydney by December. To achieve this, he will need to walk 35 to 40 kilometres a day, five days a week, while pushing his 50 -kilogram trolley of supplies and wearing his 10-kilogram suit, which he bought online.

Getty Images AIN'T LIKE DUSTING CROPS, BOY: White knight Stormtrooper Jacob French on day five of his journey for charity.

''It does get very hot,'' he said. ''The helmet is not very well ventilated. It's like wearing a bucket on your head. It's not very flexible either, so I'm moving pretty slowly. I had to have it specially trimmed to make it less restrictive.

''I hope to finish [the walk] before the weather gets too much warmer, otherwise I'm just going to get drenched in there.''

Mr French was between the towns of Mandurah and Bunbury, about 150 kilometres south of Perth, when The Sun-Herald spoke to him yesterday. As of last night, he had raised more than A$3400.

''The cars which have passed me have all given me a smile and a wave,'' he said. ''People have been tooting their horns. A lot of people have stopped and asked me what on earth I'm doing, though. They probably think I am a bit of a nutter.''

Mr French is part of a group called the 501st Legion, a collective of Star Wars devotees who enjoy dressing up as characters from the films. Last year he dressed in a similar costume for the Run Melbourne half-marathon, which is presented by The Age newspaper.

Mr French's mother, Mandy, said the family was proud of his determination. ''He has a real heart for the kids that Starlight helps and it has been a dream of his to do this for a while.''