*ducks to avoid the shower of abuse, empty beer bottles and tin cans* So, I've trawled through several threads and picked up one or two things about tandem wings, but I really don't see why they aren't more popular. I understand that if you don't get the centre of gravity correct, then they can be quite unstable. Henry Mignet seemed to (eventually) get it right, so clearly it can be done and, indeed, one of the Flea's claims to fame is its hands-off stability. I'm sure that Koen will chime in here, but aren't they technically more efficient? You've got two wings that are lifting up! The regular way involves one big wing doing all the work and one little upstart up the back making nasty comments and fighting against it! In the example of the Flying Flea, it seems to me that it's a biplane with one less drag-inducing aerofoil. Isn't that a plus? Is the stability issue for tandems that more insurmountable than a regular configuration such that it's not worth pursuing? Are there any other issues that make tandem wings less attractive? Thoughts?