Competitors in this weekend's Red Bull Air Race (RBAR) in Porto, Portugal, are predicted to have trouble slowing down their aircraft because of the tightness of the track.
The race is held along the winding Douro River, which is relatively narrow compared to what the racers are used to, meaning they will have little room to slow down their aircraft. Accordingly, the entry speed for the track has been reduced to 180 kt from the standard 200 kt.
According to RBAR's un-named analyst, pilots will have on the vertical turn manoeuvre (VTM) to bleed off speed, but doing so will run the risk of subjecting the aircraft to too much g-force.
"The first thing they might try is the 'double pull'," the analyst explained to Red Bull Media. "We saw this technique performed by Pete McLeod in Kazan." This is where the pilot applies back-stick, briefly releases the pressure and then pullsback again. "The intention is to pull above 10 g twice, but not to exceed the 0.6 sec limit."
Alternatively, pilots could "Initiate the VTM as quickly as possible, but there is a high risk of the pilot exceeding maximum g and then being disqualified," he said.
American Kirby Chambliss goes in the the Porto round with a bare minimum one-point lead over Japan's Yoshi Muroya, courtesy of winning the last two races in succession.
Australian Matt Hall is in ninth place without a podium finish in any of the five races held so far this year. Hall and his team are continuing to develop the Edge 540 racer that is new to the team this season.
"Keep your eyes on us," Hall said after the last round in Kazan. "We will get there in the end and we will get on the podium, we just need time to gel as a complete unit."
Porto hosted RBAR rounds from 2007-2009, but has been off the calendar since then. This weekend's qualifying starts at 11.00 pm AEST on Saturday with the Round of 14 starting on Sunday at 10.00 pm on Sunday evening.
The race can be seen live on the Red Bull Air Race website.