Crown prosecutor Yelena Yelavich said one woman would tell the court about a night when Roper offered her a lift home.
It is alleged he kissed and groped her as soon as they were in the car, before driving her to an area known as "the bombing range" at the base.
Ms Yelavich said the woman would give evidence that Roper reclined her seat and locked the doors as she tried to escape.
He bound her hands with the seatbelt and raped her, she said.
The fifth complainant did not know the others. She was doing work experience with Roper during the alleged offending.
She accused the defendant of molesting her while she was working and rubbing himself against her from behind.
As well as the sexual charges, there were also five counts of assault after two of the girls said he punched them in the face on several occasions.
Defence counsel Nigel Cooke said the gap between the alleged crimes and the trial would cause serious issues for the jury.
He said there were dead relatives of his client who could not testify, ACC notes were missing and school counsellors' reports from the time were inadequate.
"The difficulty, obviously, is that memories are inaccurate. Distortions and changes of emphasis occur," Mr Cooke said.
"If you've got no documents or people to stand up for you, the position of the accused is pretty dire."
He also warned the jury to prepare themselves for an onslaught of unsavoury material.
"It's a topic that we know about but never have it rammed in our face. Well, you're going to have it rammed in your face over the next week and you're going to have to deal with it," Mr Cooke said.
The trial before Judge Brooke Gibson is expected to run until next week.
Charges:
• 9x Indecent assault
• 5x Rape
• 5x Assault
• 1x Kidnapping
• 1x Unlawful sexual connection