Gig 601XL Builder wrote:

Zenith did a Cri-Cri? When was that? Any photos out there?

A very long time ago - like, in the 70's. As I understand it there
were a lot of materials substitution that proved to be inadequate.
Here are a couple of quotes from the cri-cri mailing list.


The Laison tube runs across the fuselage under the knees
of the pilot. It connects the movement of the two flaperons. It also
mounts the bellcranks for the flaperon "aileron" action, and also rotates
to make the "flap" action.

The Zenair tube is made from thin steel tube, maybe 19mm diam. It is
flexible and acts like a tuning fork. Any induced deflection of one
flaperon is amplified into the other flaperon, and you get a flutter that
continues until some connection between the flaperons breaks OR until
something ELSE on the airplane breaks and it becomes uncontrollable...
There have been 6 known cases of Cricket flutter; the one fatality was
Jim Harper.

The Colomban tube is 32mm, and made of stiff aluminum.
As you know, most people think of aluminum just for it's lightness, but
aircraft designers use the fact that it is STIFF.
The Columban tube is too stiff to transmit any induced deflection from
one flaperon to the other.

Also please tell your friend about the elevator actuator connection. The
Zenair modification (307.07m) is just 2 little pieces of bent aluminum.
They are NOT strong enough. Use the machined fitting as described in the
original plans !!!!!!!!!!!!!

The same is true for all other parts of the control system.
Cheap substitutes of parts pivoting directly on bolts instead of using
the ball joints ("heim joints") called for in the blueprint, etc., etc.
ALWAYS FOLLOW THE ORIGINAL PLANS...


and this

Hi all'
I am an IA and I have long been excited about the CriCri.
I purchased plans from Zenair in 1996 and was told by them that
I got the last set. My question is about the Zenair plans.Are they the
same plans as the desingers? I believe I read in the archives that they
are the same and you should build from them and ignore Heintz's
modifications. Thanks for your help Rocky Lennon

Dear Rocky,
You got it right, there were no "Zenair" plans, they merely
went to the local blueprint shop and ran off copies of the
"desingers" original.

Follow those plans and you will be OK.
There are 2 changes Michel approves of (but does not get involved in).

1. Go to a modern mechanical disc brake such as found on a go-kart.

2. The JPX engine is inadequate, and it looks like good progress
is being made in adapting 3W engines. See the earlier posts.

A request for you:
What is the Zenair serial # on your plans???
If they are the last set, that will tell us how many
plans Heintz stole from Michel without paying royalties...

Have fun...David