This is an accident waiting to happen. The motor mount is
incorrectly designed
with un triangulated bays and bent tubes in tension and
compression.
The firewall forward weight is at least 450 pounds aluminum
block or no aluminum
block. No mention is made of beefing up the fuselage to
take the vastly increased
bending loads during landing and high G turns not to
mention the increased
bending loads on the wing spars.  Zenairs are not over
designed to begin
with having very thin skins.

"The fuel burn is better then expected though and
I am presently confirming the JPI 450 for accuracy. Cruise
@ 11,000 msl is
producing 5.9 0 -6.3  gallons an hour."

The numbers quoted above shows a lack of understanding
about engine engineering
in general. The fuel burn quoted at 6 gallons an hour or 37
pounds
an hour means the engine is only generating 83 HP giving it
the benefit
of a BSFC number of .45. In the unlikely event the BSFC is
as low as .40 the HP
then would be 93 HP at the absolute maximum. Now you have a
450 pound
firewall forward weight putting out 93 HP at cruise.

Something is seriously wrong.

"The numbers I am shooting for are one pound of engine
weight for each
horsepower and a small total  engine profile that will
fit in most
airframes."

What he is saying here is he things he is going to get 350
to 400 HP
with a 1.43:1 PSRU ratio. With a 2600 RPM prop that is
3700
engine RPM. No way is that going to happen.

This person is totally clueless.

I am really worried here. Probably one of the most
dangerous airplanes
I have seen in a very long time.

Paul Lamar


Cheers All,
The 801 w/ the aluminum Ford V-8 belongs to Ben Haas, of
Jackson Hole,
Wyoming. The FWF limit for an 801 is 440 lbs. I think Ben
Haas has met this
threshold with the use of an aluminum block and aluminum
heads. I think it's
rated at 270HP. The 801's power range is from 150-240HP.
Ben Haas did a nice
job on both the a/c and the engine. None the less, it's a
reciprocating
engine and prone to the inherent flaws of same.
http://www.haaspowerair.com/
Here are some pics. from the Zenith website
http://www.zenithair.com/stolch801/builder-pics/bh1.jpg
http://www.zenithair.com/stolch801/builder-pics/bh2.jpg
http://www.zenithair.com/stolch801/builder-pics/bh4.jpg
http://www.zenithair.com/stolch801/builder-pics/bh4.jpg
I'm building an 801 too. N801YZ (reserved) SN 5754
I am 100% sold on rotary engines, and will be installing
one in my a/c.

Perry, Illinois., USA


Very least install some acro cables to tie the engine to the fuselage,
so when the mount fails there is some chance of getting it back on the ground.

Does anyone personally know the builder?  This is when you need to pull
him aside and build two balsa wood models so he can feel the difference
in his design and a recommended design.  Just looking at front mount
explains he doesn't realize the problem with his design.

The 4.6L Ford Aluminum engine 'dressed' weight is 435 pounds* (no AC/
but includes Power Steering pump, manual flywheel). stripped down and
adding and aluminum intake manifold and carb, distributor, a PRSU + Prop
I do not see how me made 440# FWF (more like 490# and figured 10% over
was close enough?).

Tom