51% rule

How is the 51% rule line drawn? Let's say for example I want a homebuilt
Comanche with my own choice of engine and I locate a set of plans as well as
the wings and tail feathers from a factory Comanche. If I build the
fuselage from the plans and recycle the wings and tail, is it an amateur
built experimental or a rebuilt factory aircraft? The FAA could certainly
simplify things if they would allow builders to use a proven, certified
airframe with their own engine choices in the experimental amateur built
category rather than experimental R & D.

I was shocked to see a Schweitzer 2-33 glider with a homebuilt airworthiness
certificate. The glider was assembled with parts from two or more gliders
and recovered with new fabric. There are a few strange but trivial
modifications to the original design but it is still a 2-33. It's very hard
for me to see that the rebuilders did 51% of the work. Yet it has a
homebuilt experimental airworthiness certificate.

This is the equivalent of putting Piper PA-20 tailwheel gear under a PA-22
Tri-Pacer, recovering it, and calling it a homebuilt. I always thought the
FAA considered this sort of thing an abuse of the homebuilding regulations
and would deny the certificate.

Bill Daniels

"Jerry Wass" wrote in message
...
Looks like they found a congenial FIZDOO.!

"James M. Knox" wrote:

"Robert Bates" wrote in
. net:

How is the 51% rule line drawn? Let's say for example I want a
homebuilt Comanche with my own choice of engine and I locate a set of
plans as well as the wings and tail feathers from a factory Comanche.
If I build the fuselage from the plans and recycle the wings and tail,
is it an amateur built experimental or a rebuilt factory aircraft?

It had always been my understanding that a certificated aircraft,
rebuilt, was still a certificated aircraft. A complete "restoration"
project, where you started with little more than a data plate, still
regenerated the original plane.

However, there are a couple of guys here in Austin that are (re)building
their own Piper Malibu amateur-built experimental. The starting point
is a pretty badly wrecked Malibu. They have a factory list of
directions, which includes all the different tasks in building the plane
originally. They intend to do 51% or more of those tasks in the
rebuilding (for instance, instead of buying a new wing skin, they will
make their own).

They are also going to hang a Walters turboprop engine on the thing.

In the end, although they may not have done 51% of the construction,
they will have done more than 51% of the tasks - all that the new rules
require. They have FSDO approval for what they plan to do (subject, of
course, to the usual final inspection, etc.). Should be an interesting
project.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

Thanks for the information. It sounds like it might be possible with a
reasonable FSDO.

Barnyard BOb-

What I am trying to do is find a way to skirt the edge of the FARs and end
up with the plane I want. As far as "TROLLING for choir sympathizers " I am
no troll and have never wanted a choir, I stand alone.





"Bill Daniels" wrote in message
...
I was shocked to see a Schweitzer 2-33 glider with a homebuilt
airworthiness
certificate. The glider was assembled with parts from two or more gliders
and recovered with new fabric. There are a few strange but trivial
modifications to the original design but it is still a 2-33. It's very
hard
for me to see that the rebuilders did 51% of the work. Yet it has a
homebuilt experimental airworthiness certificate.

This is the equivalent of putting Piper PA-20 tailwheel gear under a PA-22
Tri-Pacer, recovering it, and calling it a homebuilt. I always thought
the
FAA considered this sort of thing an abuse of the homebuilding regulations
and would deny the certificate.

Bill Daniels

"Jerry Wass" wrote in message
...
Looks like they found a congenial FIZDOO.!

"James M. Knox" wrote:

"Robert Bates" wrote in
. net:

How is the 51% rule line drawn? Let's say for example I want a
homebuilt Comanche with my own choice of engine and I locate a set
of
plans as well as the wings and tail feathers from a factory
Comanche.
If I build the fuselage from the plans and recycle the wings and
tail,
is it an amateur built experimental or a rebuilt factory aircraft?

It had always been my understanding that a certificated aircraft,
rebuilt, was still a certificated aircraft. A complete "restoration"
project, where you started with little more than a data plate, still
regenerated the original plane.

However, there are a couple of guys here in Austin that are
(re)building
their own Piper Malibu amateur-built experimental. The starting point
is a pretty badly wrecked Malibu. They have a factory list of
directions, which includes all the different tasks in building the
plane
originally. They intend to do 51% or more of those tasks in the
rebuilding (for instance, instead of buying a new wing skin, they will
make their own).

They are also going to hang a Walters turboprop engine on the thing.

In the end, although they may not have done 51% of the construction,
they will have done more than 51% of the tasks - all that the new
rules
require. They have FSDO approval for what they plan to do (subject,
of
course, to the usual final inspection, etc.). Should be an
interesting
project.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

"Robert Bates" wrote:

Thanks for the information. It sounds like it might be possible with a
reasonable FSDO.

To you, then....
A 'reasonable FSDO' is one who would
violate both the spirit and letter of the law?

Good luck.

Barnyard BOb-

What I am trying to do is find a way to skirt the edge of the FARs and end
up with the plane I want. As far as "TROLLING for choir sympathizers " I am
no troll and have never wanted a choir, I stand alone.

Like I said above....
Good luck.


Barnyard BOb --

"Bill Daniels" wrote in
:

I was shocked to see a Schweitzer 2-33 glider with a homebuilt
airworthiness certificate. The glider was assembled with parts from
two or more gliders and recovered with new fabric. There are a few
strange but trivial modifications to the original design but it is
still a 2-33. It's very hard for me to see that the rebuilders did
51% of the work. Yet it has a homebuilt experimental airworthiness
certificate.

One note on that... the rules changed some years back. It used to be
that you had to do 51% of the work. Now you only have to do 51% of the
TASKS, i.e. the number of different things required to build the craft.
That is what has allowed all the "quick build" kits to be legal.

For example, you don't have to make 200 wing ribs. You can make ONE
wing rib, and the factory can make all the others, and it counts the
same. The theory being that the homebuilt rule is there for education,
and you don't get much additional learning making wing rib #183. G

So it's *possible* to do a *lot* of significant things to an airframe
and meet the 51% rule, even though it looked like the plane was pretty
much there to begin with. [Some "quick build" kits have the basic wings
and fuselage halves already made. Stick those four parts together and
it looks like an airplane - but there is still a WHOLE LOT of work left
to do.

As someone said, it's all about finding a friendly FSDO.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

On Fri, 25 Jul 2003 09:30:10 -0500, "James M. Knox"
wrote:

"Bill Daniels" wrote in
:

I was shocked to see a Schweitzer 2-33 glider with a homebuilt
airworthiness certificate. The glider was assembled with parts from
two or more gliders and recovered with new fabric. There are a few
strange but trivial modifications to the original design but it is
still a 2-33. It's very hard for me to see that the rebuilders did
51% of the work. Yet it has a homebuilt experimental airworthiness
certificate.

One note on that... the rules changed some years back. It used to be
that you had to do 51% of the work. Now you only have to do 51% of the
TASKS, i.e. the number of different things required to build the craft.
That is what has allowed all the "quick build" kits to be legal.

For example, you don't have to make 200 wing ribs. You can make ONE
wing rib, and the factory can make all the others, and it counts the

I thought I'd had lots of practice with fiberglass when I started, but
although my early work was plenty sufficient and strong, it's easy to
see the difference between my early work and the current.

same. The theory being that the homebuilt rule is there for education,
and you don't get much additional learning making wing rib #183. G

So it's *possible* to do a *lot* of significant things to an airframe
and meet the 51% rule, even though it looked like the plane was pretty
much there to begin with. [Some "quick build" kits have the basic wings
and fuselage halves already made. Stick those four parts together and

I think you will find that the "Jump Start" Glasair-III has a lot more
than that. (Unfortunately I can't get the Newglasair site to come up
today.) As I recall the fuselage halves are joined, the fire wall is
in, and the engine mount reinforcements are done. The wing is ready
for the flaps and ailerons and the horizontal stab is about ready to
close. They save you about 1000 hours or so... However considering
the G-III is one of the most labor intensive "kits" out there, you
still have a long ways to go.

A little more work and I'll be up to the point where my G-III will be
as far as a "Jump Start" kit out of the box. sigh Course, mine
didn't cost any where near what the Jump start kit does and I have an
engine and prop.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)
it looks like an airplane - but there is still a WHOLE LOT of work left
to do.

As someone said, it's all about finding a friendly FSDO.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

"James M. Knox" wrote:

I think the "fast build" or "jump start" kits are a great idea for the
overall homebuilder movement.

I agree. I was pretty proficient at riveting after the
first 50 or so. The remaining 11,950 rivets just allowed
me to perfect my technique :-)

Dave 'smash' Hyde

RV-4 slow-builder
looking for a DAR...and a 'chute rigger

On Tue, 29 Jul 2003 08:21:58 -0500, "James M. Knox"
wrote:

Roger Halstead wrote in
:

... As I recall the fuselage halves are joined, the fire wall is
in, and the engine mount reinforcements are done. The wing is ready
for the flaps and ailerons and the horizontal stab is about ready to
close. They save you about 1000 hours or so... However considering
the G-III is one of the most labor intensive "kits" out there, you
still have a long ways to go.

Exactly. There are still a LOT of tasks left to occupy your "spare time."
G

I think the "fast build" or "jump start" kits are a great idea for the
overall homebuilder movement. It allows more people to consider building
(without the corresponding filing of divorce papers). It allows the
manufacturer to pre-make some of the larger and critical assemblies that
are less practical for the average builder to do in their garage. And it
quickly gives the builder something, no matter how many hours of work
remain, that at least starts to LOOK like an airplane. [A very important
psychological factor in getting the thing finished.]

sighIt sure nuff is! I keep hoping that my G-III will start
looking like an airplane one of these days. Maybe when I mount the
horizontal stab and elevator?

This week, while my wife is on a bike tour, I'm frantically working on
the horizontal stabilizer (Yes, I know that is the first then they
have you work on, but mine was postponed while I worked on the bigger
stuff.)

I'd like to get it closed before sunday and I *might* make it if I
don't get distracted.

I really don't know how many hours I've put into the G-III so far, but
my builders diary is pretty much up-to-date and accurate. I've just
never bothered to total the hours. It covers 8 large internet pages
and well over 100 printed pages. If I continue at this rate it will
be the size of an encyclopedia by the time I have it finished.

Had I started working on the thing at the current pace back when it
was delivered, I would have been flying it for the past two or three
years. "The project" has been like the remodeling of the kitchen.
Once you start you keep seeing more things that need to be done. The
basement is too small except for the horizontal stab. The garage is
too hot in the summer and too cold in the winter. It also has too much
*stuff* in it. So I ended up building a 28 X 40 foot shop

I've been truly working on it for a bit less than a year and a half,
but I haven't reached the point where it would equal the "jump start"
kit, out-of-the-box.

A couple of friends have been after me to let them help, which is fine
by me. One was over the other night and after the "grand tour" and
progress report he has decided he is most likely never going to
attempt to build one. I did explain there are a number of kits out
there that only take a fraction of the time required for the G-III,
but I think the detail to which the kit goes scared him off. (I'm
right at the point of doing the engine mount reinforcements on the
back side of the fire wall and that thing is built like a tank)

He was impressed at the size of that big massive main wing spar. I
hope he never compares the carry through in his Cherokee 180 to
it:-))


And, of course, you are still free to start with a blank sheet of paper and
a pencil if that's what you want.

One of the guys in Chapter 159 built an "almost full size" Stager
Wing. (I think it's 7/8ths) He used a different airfoil and they ran
computer simulations on it at either JPL, or Cal Tech.

His only guide was photos, sketches, and discussions. The thing is a
work of art, but from start to finish was over 30 years.

I'd love to have one of the "Jump Start" kits, but when I figure what
one costs (you really pay for that extra construction), I have the
complete G-III kit with updates , A 300 HP Lycombing K1-A5 to
rebuild, an almost new Hartzell 3 blade prop, and a heated (and air
conditioned) shop, for less than the cost of the "Jump Start" kit.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

On Wed, 30 Jul 2003 14:36:20 GMT, Peter Dohm
wrote:

Forgive me for possibly being a bit obtuse. Somehow I have less difficulty
understanding an FAA representative's rationale for issuing an experimental
(alledgedly homebuilt) airworthiness certificate for a modified, but
previously type certificated aircraft, than I have understanding why an
owner would want them to do so.

One guy up at HTL rebuilt a Lake using a Corvette engine. He also had
to do a lot of modification to reach the 51% rule, or what ever they
wanted.

As to why? I sure wouldn't except for wanting to do something
different.


In general, there are less restrictions on the operation af a certificated
aircraft than there are for an experimental, especially for international
travel and (alledgedly) for IFR; and commercial operation is prohibited for
experimental aircraft.

I don't think domestic IFR operation is a problem. There are a lot of
G-IIIs and Lancair IVs that are full IFR.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

Peter Dohm wrote in
:

... why an owner would want them to do so.

In general, there are less restrictions on the operation af a
certificated aircraft than there are for an experimental,
For many of the descriptions in this thread, an STC would seem
(outwardly) to be the more efficient process.

If you were going to restore the certificated aircraft back to a
condition consistent with its type certificate, maybe with only VERY
MINOR changes, then you would probably be correct. But in this case
they are going to wind up hanging a foreign turboprop engine on the
thing, change the fuel system, etc. (in addition to turning it back into
an airplane again G).

I know the son of the guy who did the Jet Prop Malibu STC, and I also
worked with GAMI on the original GAMIjectors STC (my plane was the TSIO-
360 test aircraft). For the Malibu these guys are rebuilding, figure
that even a one-time STC would probably run them $2,000,000 and take
four or five years (after the plane is flying). Not to mention having
to go through a lot of it all over, every time they decide to change
something. And for all that time they won't be able to fly anything but
very limited flights, with no one else on board, in designated areas,
while paying five times the normal insurance costs.

Sure, they are going to wind up with a one-off plane that only they can
maintain, probably can't be sold at a reasonable price, and will never
recover all their sweat equity. But isn't that what homebuilding is all
about anyway? {:)

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------