Regular readers might recall an item in the October issue about one of the Brabham BT25 Indycar’s tubs having been blown apart due to an inadvertent spark while being verified by the USAC Tech Inspection team. Nick Goozee a Brabham team mechanic at the time, and who was given the job of repairing the damaged monocoque recalls it differently.
“Projects such as the BT25 were a ‘wouldn’t it be a good idea if… scenario, begun at the last moment,” he says. “There was none of the forward planning of today. An Indy project was effectively just something to occupy the troops over the winter months…
“The problem was there were very few troops back then, so the bulk of the BT25 was done by four of us, building two complete cars and three tubs after the end of the 1967 season and before everything was shipped sea freight to the States around March. And by the way, also build the Formula 1 cars which for ’68 had the new four-cam Repco engine… “
The BT25 was the first monocoque-chassis Brabham. Unlike the later F1 BT33 its tub had a fully integrated tubular engine bay and front bulkhead, the two ends being joined by tubes around which the monocoque fuel cells and seating area were constructed. It was very heavy. “
I didn’t go to Indy as I was with the F1 team, but I obviously heard the facts and ultimately repaired the damaged tub. The BT25’s fuel filler, or vent (not the quick-fill filler which is further forward), was alongside the cockpit. Here fuel was put into the car under normal conditions, and one was cracked open while filling in a race to let the air out.
“The Repco engine had its distributor at the front, and for some reason the cap had been taken off and laid forward into the cockpit. The fuel vent had been left cracked open when everyone went home, and overnight fuel vapour had filled the cockpit. There was always a whiff of fuel in garages then, so for the mechanics to smell fuel would not be unusual when they came in the following morning.
“It was also first practice to remove the plugs and crank the motor over to raise oil pressure, and for some reason on this occasion the fact that a) the distributor cap was in the cockpit and b) the fuel system vent was cracked open wasn’t noticed. There was only a low-level explosion, but by pressurising a large area of panelling the net result blew the seatback panel from its rivets, and unstitched one side skin along part of the top fold and the arm cut-out panel. After Indy the tub returned to Byfleet, where I repaired it. Yes it was a stupid mistake, but low-level… with high-level embarrassment!”