Frequently Asked Questions

For a FAQ from Zenith Aircraft Company about kitplanes, click here.

For information about the Zodiac CH601 from Zenith Aircraft Company, click here.

These are the questions that are frequently asked to me after people visit this site:

What would you do differently if you started over?    New 10/01!
What performance do you expect with the Subaru engine?   Updated 10/08!
How long does it really take to build?
Doesn't the Zodiac use a non-conventional aileron hinge?
Where are the flaps?
Is the plane really made with pop rivets?
What else is 'unusual' about the design?
Why did you choose the 601HD instead of the 601HDS?
Can I build it in a one-car garage?
Why did you choose the Taildragger variant?
How much is it really costing?
Would you buy this kit again?

Have a different question? Mail me.

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What performance to you expect with the Subaru engine?

I don't know.  Zenith has pretty much declined to comment on performance with the EA-81 engine.  I don't know why.  Stratus doesn't have specifics for a Zodiac.   And its extremely difficult to compare with other people's planes due to differing configurations (HD/HDS, Trike/Taildragger, NSI/Stratus, different EA-81 variants, different instrumentation (pitot/airspeed) systems, etc.), installed equipment and a wide range in empty weights.  Plus there aren't many Subaru Zodiacs flying (yet).  I'll post my performance figures when I get them.

I am hoping for no worse than with the Rotax, and maybe even better.

UPDATE: Here are the preliminary performance figures for my plane.

How long does it really take to build?

I'm certainly not done, and this is my first project so I'm sure there is some stuff I haven't even thought about having to do yet, but I am hoping for about 800 hours in 1 1/2 years. The plane really is pretty simple to build (much simpler than an RV).

UPDATE 10/16/97: I have decided that Zenith's claim of a 400 hour build time, for a first time builder, IS possible providing you are building a bare bones airplane (which is what Zenith says). Extra things add significant time. Priming the plane was a LOT of work and definately slowed things down. I have been working only on wiring and instrumentation and avionics for the last MONTH! or so. Figuring out how to connect a dual ignition system, add an access panel to the rear fuselage, etc, etc, all add extra time quickly. Not that this is necessarily bad - if I didn't like it/think its worth it, I wouldn't be doing it. I'm still shooting for no more than 800 hours in about 1.5 years.

UPDATE 10/01/99: Ok, I've actually flown the plane now... lets see, it took me 701 hours of building time and 72 hours of 'analysis' time, according to me logs.  And about two and half years of actual building time.   One should note that I built very leisurely... 701 hours/2.5 years = 46 minutes/day spent building, on average.  I primed all surfaces, deburred everything, added a fairly complex instrument panel and one or two small modifications to the design.  I still agree with what the above update says.

Doesn't the Zodiac use a non-conventional aileron hinge?

Yes. There is no hinge. The aileron is connected to the main wing by a solid piece of 0.016" aluminum skin (actually, the top of the aileron itself). This skin flexes as the aileron is deflected. Chris Heintz (the designer) writes that tests show the hinge will last forever. In real life the prototype has been around since 1984 and is still fine. Since many people do not believe any of this, the plans show how to substitute a standard piano hinge. I've stayed with the 'flexing' skin hinge myself.

Where are the flaps?

There are none. By virtue of its light weight (570 lbs*) and the large cross-section wing, the Zodiac is able to achieve a stall speed of 44 MPH* without the added complexity and weight of flaps. At first this bothered me so much I rejected the Zodiac as a design for me and threw out their info pack. After thinking about it a while I found I couldn't really come up with a reason a plane had to have flaps if its stall (and landing) speeds were so low anyway. Thus I have actually purchased a total of two info packs from Zenith.

*All numbers are Zenith's. Stall speed 44 MPH at 1080 lbs gross weight.
UPDATE: My measured stall speed is actually 40MPH at 1200lbs gross weight, 38MPH solo.

Is the plane really made with pop rivets?

Yes. Well, they are not 'Pop' brand hardware-store rivets, but rather Avex brand blind rivets. This is one of the reasons for the quick build time of the Zodiac compared to the RV series. The main wing spar is made with solid aircraft rivets, set at the factory. For more information from Zenith, click here.

What else is 'unusual' about the design?

• The rudder is of the 'all-flying' variety, that is to say there is no vertical stabalizer except for the rudder itself. This results in a somewhat 'blocky' look to the tail of the plane at the rudder/fuselage junction, even with the fiberglass saddle Zenith includes with the kit.
• Instead of turnbuckles Zenith uses two small pieces of angle aluminum set end-to-end and held together by an AN4 bolt and nylock nut. By tightening the bolt the tension on the cable is increased.  Seems to work, but doesn't allow for much adjustment of cable tension before you have to find a different size bolt.
• The canopy attachment system is different.  It allows the canopy to swing open from both the left or right side (one at a time).  I had a very hard time (in other words, couldn't) getting the canopy to seal all the way around at the back of the plane.

Why did you choose the 601HD instead of the 601HDS?

I am more interested in the slow stall speed/short TO and landing distances than in cruise speed. Also the HD is about $1000 cheaper (even though the wing is longer!)

Can I build it in a one-car garage?

I have built everything so far on a 4x8 sheet of particle board set up as a workbench. The ends of the wing panels hang off the end of the table by about 2 feet. So yes, I think it could be built in a one-car garage (obviously excluding final assembly and wing fitting!).

Why did you choose the Taildragger variant?

I think it looks better while its on the ground. Faster. Slicker. Of course, I'd never actually flown a taildragger when I made this decision...

How much is it really costing?

Well, this is how much I've spent so far:
 

Would you buy this kit again?

Yes.  But I not sure I'd buy the firewall forward kit again, though.  See My Opinions for more.

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