Informavia

There's something about using AVGAS 100 LL on our Yaks: this 100LL contains 0,56 grams of tetra-ethyl lead per liter. That is eight times more than the mogas fuels in ancient times. And this is a problem when a radial engine does not run very often. In that case water stays in the oil instead of getting boiled out. The combustion byproducts of the lead in Avgas 100LL chemically react with that water and make an acid. This of course is very corrosive.

I have calculated the performance/weight ratio of my Yak 50:
The empty weight of the RA2005K is 720 kg This is calculated: the original weight according to the aircraft's books is 750 kg; I replaced equipment and gained a measured 30 kg.
With a (heavy) pilot and full fuel plus oil, the total weight at takeoff is around 900 kg.