On Dec 30, 7:00*am, wrote:
which would
you feel more comfortable behind?
-----------------------------------------------------------------------------------------

Either, assuming I had done the conversion.

---------------------------------------------------------------------------------------
What hp do you believe the type IV can produce,using
your given reliability constraints?
--------------------------------------------------------------------------------------

My T-4 experience is limited and I'd prefer not to guess. Any talk of
'Horsepower' would have to be based on verified, reproducible figures
from a torque stand.
As for my 'reliability constraints' there's really only two: The
modifications done to the lubrication system being the one and
attaching the prop to the clutch-end of the crankshaft being the
other.

The interesting point here is that the Type 4 engine already has the
lubrication mods BUILT-IN... indeed, ALL modern engines do. As for
driving a propeller from the pulley-hub of a crankshaft, this was a
post-war expedient which worked fine up to about 25bhp but became a
constant source of trouble -- and of increasingly complex and costly
'fixes' from that day to this, when in fact the best solution is to
simply do what is done with ALL OTHER engine conversions and put the
prop on the clutch-end of the crankshaft, which certainly makes more
sense in that the Type4 uses a flanged crankshaft .

------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Could you estimate the installed
weight differences *between the installations?
----------------------------------------------------------------------------------------------------------------------------------------------------------------------

An honest figure is probably about thirty pounds.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

The Type IV is the only truly modern air-cooled engine Volkswagen has
every produced. In doing so they drew heavily from the Corvair. Some
aspects were better than the Corvair; a few were worse (such as the
valve seats) but on the whole the 1700 and it's follow-on's (ie, 1800
and 2000) offered the homebuilder a rare opportunity. Alas, due to
the untimely death of the CEO the company fell into the hands of the
bean-counters and the moment was missed, relegating the Type IV to a
minor role and continuing to slap patches onto the Type I despite the
myriad flags of warning that it's day had long since passed.

If you happen to have a Type IV -- and a tame machinist with a heavy
background in converting auto engines for flight, in my opinion you'd
be wise to consider using it in your Jodel.

-R.S.Hoover