Advice please. Son Jason and I have recently acquired an almost complete Ziroli 51 which needs a lot of remedial work before flight. I have just had to make a new front bulkhead and reinforce the sideframes to take the bellhousing of a Xenoah 62.
As built the original bulkhead had no downthrust or sidethrust. Zero, zero. Have been able to borrow a plan from Paul Dudley and it shows no side thrust, but although the plan is a bit unclear it appears to show a tad of down thrust, no mention of dgrees.
The new bulkhead now has just a tad of down thrust and the spinner seems to match the top of the cowling OK.
Any advice please as to what is correct in practice from those who have flown them.
For what it's worth my CompARF P51, same size flies perfectly well on zero zero down/sidethrust
Thanks
John Webb 800