I wonder about wing loading though.
ORIGINAL: erbroens
That would haul the mail with a P-70!!
I fly a 1/8 scale L-39 with a P-60, with the current max rpm set to 150k... it flies and lands very nicely, even if it is slightly overweight. The same could be done with this bigger L-39 setting the P-70 max rpm to match the pilot preferences. However, it is nice to have the option of some extra power sometimes..
Enrique