Pete,

This is a very complex issue which involves a bunch more variables than
the three big ticket ones I'm going to mention (fuel delivery for one).
Internal to the engine, crankshaft stresses, bearing loads, and oil
scavanging/delivery are the three largest concerns for Aerobatic class
engines. The first two are also significantly affected by what prop is
being used (low inertia, high inertia), however based upon empirical
comparison with other engines which are Acrobatically rated, the
DeltaHawk is in pretty good shape on those two fronts (our crank is
stronger and we have more bearing area). Oil however is another story,
the current Deltahawk's are only designed with oil scavenging occurring
in one direction, down. There are separate sump systems for the upright
and inverted models and while they work fine in their intended
orientation, we have not done significant negative g testing with either
configuration. It is our intention to pursue this type of testing in
the future, as well as test a configuration of the engine with both sump
systems active, however to date we have not.

Currently the engine is intended to duplicate the performance of the
Normal (+3.8,-1.52) and Utility (+4.4,-1.76) classes (I say mimic,
because all the initial engines will be registered on experimental class
aircraft and limitations will be set by the builder) and our flight
testing thus far has not uncovered any problems with these performance
envelopes.

Hope that answered your question.

Dave Driscoll
DeltaHawk LLC



Pete Schaefer wrote:

OK, cool. I got some questions.

The site says the engine is not suitable for aerobatic use. What are the
operating limits of the engine, specifically the inverted V-4.

Pete


"Dave Driscoll" wrote in message
...


In addition to being an lurker and occasional poster on RAH, I also
happen to be one of the engineers responsible for the DeltaHawk (or the
sole reason the engine hasn't been in full production for the last 3
years according to the marketing guy). In any case, as this is one of
my few areas of RAH expertise, I'd be happy to answer any questions that
people may have regarding the project.