I’ve been wondering about gull-wing doors lately. In particular, I’ve been wondering how they affect the structural rigidity of a vehicle. Let’s look at a few examples to see what I mean.

(Image shamelessly ripped from Wikipedia)

In the case of the Mercedes Benz 300 SL, it seems to have a very thick door sill to compensate for the lack of support in the roof. Let’s look at another example:

(Image again shamelessly ripped from Wikipedia)

The Delorean DMC-12 doesn’t seem to have the same door sill. So how is the Delorean’s chassis not floppy as a piece of room-temperature, week-old celery?

How is it possible to have both gull-wing doors, and a stiff chassis without having a huge door sill? Also, how does the missing chunk of the roof affect rigidity along the A-pillar?

I would think that you would want a continuous line from the A pillar up, across the roof, and back down the B pillar to give some strength, in particular in the event of an impact on the top of the A pillar.