sigrun

"Blue sky, moderate cumulus with a speck of higher cirrus in a vrtually windless autumn sky"

sigrun I hate you, in fact I am going to get up early tommorow so I can hate you a bit longer.
only joking of course.

The Groovy 3A has no dihedral each wing half slides onto a aluminium and composite spar, which is eqadistant from the top and bottom of the wing.

As to the 4S 2S debate we will have to differ on most of the points you have raised concerning power and the relative attributes of the different engines, I do not whant to get into a big debate about this but your quoted power figures for the 4S is down on actuall real time and your quoted figures for the 2S are up on what they realy achive, however the difference in responce time whilst powering up from the 4S too the 2S is worth staying with the 4S, if its the choise of all the competetors in the world F3A championships who were using IC its indisputable that the 4S is the best choise for this discipline.

Incidently I have more 2S than 4S so I rearly do not have a bias one way or the other, 2S just tend to be better for all out speed because they sound fast revving like there is no tommorow.
My highly tuned Webra 50 will go to 22,000rpm on a 9x8 and produces only just 2bhp measured not not taken from manufactures litrature.
I have never measured my Pico 60 but it certainly turns a big prop with authority, but tends to be a top end engine pulling from low revs is not its thing.
Horse's for Course's as it were.

Your bias is showing tuck it in, no offence intended.

Mike