Index Home About Blog
From: (Johnny)
Newsgroups: rec.aviation.homebuilt
Subject: Re: mini 500
Date: Wed, 28 Apr 1999 07:14:13 GMT

On Tue, 27 Apr 1999 11:35:35 -0400, "General BBbboomer"
<> wrote:

>Otto, otto,otto. You otto get your head examined. Are you that simplistic?
>How many people buy a kit believing that it is an unproven design that damn
>well may take their life the first few hours? Well Otto, how many?
>Just the fact that the buyer is required to sign a contract stating they can
>not make any modifications to it removes the "experimental" nature of it to
>me. If it is so experimental why is the builder not allowed to experiment
>with it?

 Steve, you've become dangerously complacent. Just because it's a kit,
doesn't mean you're not still the test pilot, and continue to be on
every flight. Just because the manufacture makes it sound like it a
pat deal, doesn't remove the experimental airworthiness cert and
replace it with something that will go Part 121.

Don't misunderstand me here. I think the seller should disclose as
much information as possible to the buyer, for the protection of both
parties, and it's wrong to lie about a product to get more sales. Even
when that code of ethics is adhered to absolutely, it is still up to
the buyer/builder to determine the airworthiness of the craft. Assume
nothing. Run your own tests. Believe your own findings. Communicate
with others attempting the same thing you are. Assess your own level
of risk.

It is truly a "buyer beware" scenario.

The great contradiction to this reality is a purchase agreement that
tries to limit the buyers ability to do these things with a "no mods"
clause. It attempts to lock them in to any mistakes the manufacturer
may have made. Any design flaws they may have passed along with the
product. It forces the buyer to persist with something that may never
be workable without changes being made to the basic design. When the
manufacturer refuses to help the customers solve any possible design
flaws it only adds insult to injury.

As for testing before marketing; first of all, the seller should be
honest about how much testing has actually been done, regardless of
anything else. I don't see anything wrong with trying to market
something that is unproven as long as you advertise it as such. Many
new designs have problems at first, and the buyer should be made aware
of the fact that they will probably be the one that will be
discovering what those problems might be. To go into a deal as the
buyer of a box full of parts that you are going to put together and
then try to fly, without first asking a lot of questions, is probably
ignorant on the part of the buyer. To falsely claim extensive testing
when no extensive testing has actually been done, is in my opinion,
criminally negligent on the part of the seller. The golden rule here
is to always conduct business with the utmost integrity.

As for testing to destruction, sometimes that happens unintentionally.
IOW, you are testing an assembly of parts, and before you get to the
required performance level, something breaks. You fix that part of the
design, re-test, and something else breaks... etc., etc. Finally, you
get to the point where you are getting the desired performance,
repeatedly, without anything breaking. Are you going to test to
destruction after that? There is probably no need to. The testing that
is left is to find out how long you can reliably operate to the
desired performance limit before something wears out and/or breaks.
This isn't testing to destruction if you get to the desired TBO BEFORE
something breaks. Testing beyond the desired TBO is done to increase
the published TBO, by proving that it will actually go longer than
initially thought. But even at that, a "real life" TBO can't be
accurately stated until many copies of the unit have made it there
while operating within the design limits. That's why when a potential
customer asks me what the TBO of one of my engines is, I tell them "I
don't know yet". If they are not comfortable with that, I suggest to
them that they should fly with a powerplant they are comfortable with.

In the case of a helicopter, there are a few parts that wear out,
repeatedly,  long before the rest of the aircraft does. These parts
are given a life expectancy and replaced as routine maintenance before
they are worn out. If there are no such parts mentioned in the
maintenance manual of the helicopter, I would suspect that there was
not enough testing done yet to determine what those parts may be, or
what there expected life spans are.

Sometimes, in a tiny little low quantity market, like experimental
aircraft, it is not feasible, or even possible, to test a large
sampling of a product before the customer is brought into the picture.
Let's say for example that someone calls me up and asks me to build a
PSRU for an engine that they have, that I haven't ever built a PSRU
for before. This is usually relatively easy for me to do as the design
is rather modular and easy to adapt to most any engine. I know that
the main components of the PSRU will work reliably on other engines of
the same power and similar configuration. Does this mean that
everything will be OK on this "new" engine? Maybe... but maybe not. No
one knows for sure until it is tried and tested. The customer is not
willing to pay for anyone to build several of these units and test
them to death. I may never get another call for a PSRU for his oddball
engine, so I'm not willing to absorb the development costs either. The
customer must be willing to accept the responsibility for whatever the
outcome may be with this "new" design. I can't tell him it will work
if I've never tested it before. If he accepts those terms, I build the
unit and then anxiously await his test reports to see how well it

Is purchasing and building an aircraft kit any different? In my
opinion, it is somewhat the same. The manufacturer should be honest in
telling the customer how much time the prototype has accumulated. If
the prototype is still low time, then the customer has to be willing
to do whatever it takes to see the design through the development and
test phase. If they aren't willing to do that, then they shouldn't buy
in at that point. If they are willing to do that, they will expect to
have to fix some problems and make some changes.

In the case of the mini5000, I have a feeling that a large percentage
of the customers probably should have had their eyes opened wider than
they did. I get this feeling from seeing their willingness to sign a
purchase agreement that forbids any modifications to the design of an
experimental aircraft. That and there willingness to fly a helicopter
with a 2-stroke engine!

I sincerely hope that the builders stick together on this and go
through the steps of resolving any design problems. Regardless of if
they get any factory help or not. A sexy looking turbine powered one
place chopper is just possibly the ultimate toy.

-j- (oops, did I say turbine?)

Index Home About Blog