From: ken@systech.com (Ken Brown)
Newsgroups: rec.aviation
Subject: Re: Building a Christavia, #12 plans problems?
Date: 14 Aug 92 18:08:49 GMT
Organization: Systech Corporation, San Diego

In article <1992Aug13.144849.25866@dartvax.dartmouth.edu> Charles.K.Scott@dartmouth.edu (Charles K. Scott) writes:
>
> Building a Christavia - Plans comment
>
[...]
>else would.   I wonder if other builders could speak to the
>completeness and accuracy of the plans they are working with? 

I am building a Pazmany PL-2, and the plans are *very* complete, but
I understand that this is the exception rather than the rule in the
homebuilding industry.

I must admit that one of the reasons that I chose the PL-2 is that
there used to be an organization (I don't know if they are still
around) called NASAD that would grade homebuilt airplane plans w.r.t.
the amount of detail that was included, the complexity of the parts to be
made, and the safety/airworthiness of the finished product (as designed).
They absolutely raved about the level of detail contained in the PL-2
plans. Their only complaint was that some of the machined parts for the
landing gear might be too much for Joe or Jane Homebuilder to fabricate
in his/her basement.  (I took a Machine Shop class at a local adult
school, and milled out my L.G. scissor parts there - and learned how
to use a mill at the same time.)

The parts list includes AN hardware, instruments, and even sheet
utilization diagrams for getting the most parts out of a sheet of
aluminum.  So far all quantities have been correct.  The plans even
show flat patterns for most parts, the bend radius of every bend,
and dimensions are called out the way they do in aerospace industry
(two decimal places means +/- .030 inch, three decimal places means
+/-.010 inch, etc.).  Paz wants to hear about any discrepancies and
will issue ECNs as necessary (he is up to ECN #5 now).

The plane (2 place, SBS, tricycle landing gear, low wing, aluminum,
sliding canopy, 108 - 150 HP Lycoming engine) was designed in the
early '60s and incorporated a number of features that weren't included
on other designs at the time.  Fuel is carried in tip tanks to keep
it away from the passengers during a crash, shoulder harness, a
cockpit that is designed to deform outward on impact, 6 inch travel on
the oleo-strut landing gear.  There was an article on two PLs in New
Zealand in either the July or August issue of Kitplanes Magazine.

As a testament to the quality of the design, the Taiwan Air Force chose
the PL-1 (the predecessor to the PL-2) as their primary pilot trainer.
I've heard that it is the only homebuilt airplane listed in Jane's
Military Aircraft book.

My only complaint with the project is that there are so darn many parts
to make.  For example, there are 9 ribs in each of the ailerons.  Look
at any Warrior and you will see maybe 3 ribs, and a lot of stiffening
beads pressed into the sheet metal.  The Piper way is cheaper and quicker,
but heavier because of the thicker metal required.  Pazmany's philosophy
is to keep it light.  You only have to build these 9 ribs once, but
they will always be lighter than the Warrior.


This got rather long, but you asked about "my project".

>
>Corky (slightly daunted now but still moving ahead) Scott

Hang in there.  They say the feeling you get on that first flight is
worth it.  (But I bet the pucker factor is off the high end of the scale!)


Ken Brown          (619) 453-7400 x234
Systech Corp.      ken@systech.com
San Diego, CA

"If it ain't broke, don't break it."