Originally Posted by
Genghis the Engineer
FlyingStone - yes I meant the DA20, but I disagree with you about payloads. Take for example a Grumman AA5: IMC capable, MTOW 998kg, typical empty weight about 670kg - that's 1/3rd payload. (Strangely my 1947 4 seat taildragger which has been happily doing long trips for 64 years quite safely is rather better than that, but I'll work with the Grumman as an example.)
So, at 750kg, using the same fraction, that gives 250kg useable payload. Bang on 2x90kg plus 100 litres, or 5+ hours (with a modern engine such as the 912), of fuel.
For that matter, shave 8kg off the MTOW of a Cessna 152 and you have an IMC/night capable aeroplane that falls into the VLA category, with an exemplary safety record, and 260kg useable payload.
I think the additional weight on DA20 (which comes with BEM of ~ 550kg) is due to a bit larger permissible flight load factors, which are +4.4, -2.2 for DA20 and +3.8, -1.52 for AA-5 (I believe due to restrictive Part 23 standards for utility category aircraft). The C152 has quite similar permissible flight load factors, but on the other hand - it's the same weight as DA20 and slower for about one third.
Well, anyhow, discussion about VLA weight will most likely be redundant, since the proposal is to lift the MTOM for aircraft certified according to CS-VLA to 890 kg and at least one problem of the standard will likely become history.