The Spyker Formula One team have been forced to postpone the debut of their B-spec car until the Italian Grand Prix after the machine failed a rear impact test.
The car, which had already been delayed for a few months, was set to make its debut at this weekend's race in Turkey.
"It's obviously very disappointing to delay the launch, especially considering the hard work that everyone at the factory and track has put in," said chief technical officer Mike Gascoyne.
"Unfortunately last week we had an unexpected failure of the rear crash test, possibly due to problems with a batch of material used. Unfortunately all the other structures available we had to test were from this batch and the modifications we tried to make were not sufficient.
"These tests are quite rightly very stringent and difficult to pass, but we did not expect to have a problem as the structure is very similar to the A spec one. We are confident that we understand the problem however and should be able to pass with no problems next week."
The team, yet to score a point this year, will race this weekend with the A-spec car.
Gascoyne was happy that at least the team would now be able to test the B-spec machine before racing it.
"We will now concentrate on doing the best we can this weekend," he added. "As we were aware we had a problem we brought two A spec cars as well as two B spec cars, so we will not have any problems switching back, but it's just disappointing not to have the performance increase as planned.
"On a more positive note, we will now be able to test the car at the pre-Italian Grand Prix test next week at Monza, which should allow us to be in better shape."