Hello

New on this forum and a restarter at modelflying
after a period (15 yrs) of non activity (kids etc )
Flew last with a laser200 with a OSFT160 boxer.
(still have it) Want to start slow again and now building
a Piper Cub (70''span or 1850mm) and also have a Pt-19
ARF(span 58"or 1450mm) waiting next . Want to fly both
with a 4stroke and as I want to keep spending money to
a minimum but do want a good quality engine I'd like to
get 1 engine which can power both. The piper manual
tells me it can be flown with a .40 2 stroke . Does not
give me an equivalent for a 4stroke. The PT19 also to
be powered with .40 to .46 2 stroke and up to .52 4str.
I would like the Piper to be able to do some aerobatics
like loops and rolls but should also be able to fly slow.
I was thinking of something in the order of a .60 4stroke.
Is this oké or is it too powerfull or heavy for the PT19 ?
Someone said to go safe on power and go for a .70[X(]
This could maybe be oké for the Piper but the PT19 may
get to nose heavy (I'am not worried about power as that
can be controlled) So in short what would be the minimum
displacement for a 4stroke for the Piper and the max for
the PT-19. Both about 2,5kg (5,5lbs) take off weight.
Any advice on engine size and brand will be appreciated.

Thks
Yetvart