ZDC Construction Photos

Page 2a: Construction & design photos
-- Zodiac C-GZDC (and occasionally other Zenairs)

Larger version is 86k
(1999 with minimal interior)
Instrument panel
Features:

Shock mounted flight instruments: The standard six except DG replaced by G-meter. (G-meter shows max/min values from trailering the plane to the airport!) The gyro instruments were moved to the bottom row so their longer cases would clear the sloping gas tank. Suction guage mounted close to the flight instruments.

2 axis MAC trim, activated from pilot's stick grip. Both grips have PTT button. Only a single PTT circuit was used; two would have been better, to allow activating only one mic at a time when transmitting.

Throttle handles mounted vertically, and low in the panel. This allows the throttle hand to be comfortably rested on or braced by one's knee.

Near the throttle are mounted the fuel boost switch (red switch to the left) and the Ivoprop prop pitch control (small black sub-panel beneath pilot's throttle, difficult to see in photo).

At top centre of panel: Alternator warning light (as per standard Rotax 912 installation), ELT indicator/switch, EIS master caution light.

Engine instruments: Main display is the Grand Rapids Technologies EIS engine monitoring system. Other gauges are manifold pressure, amperage charge/discharge, coolant pressure, and capacitive fuel gauge.

Glove box on right hand side, sized to fit pens, sunglasses, etc., and a custom sized flight manual.

Central sub panel: Panel kept narrow at the bottom to not interfere with the knees of taller pilots. Radio at the top, and switches below. These include a 6 switch & fuse combination panel from an automotive store. Convenient but cheaper in quality than desired. The Microair 760 radio is inexpensive yet sophisticated. It is small in diameter and in depth behind the panel. The small size can be a disadvantage for viewing and activating switches. The radio also has a simple, non-VOX intercom built in, which is sufficient but not great.

Fuel shutoff valve extension is brought from the forward fuselage tank to a point just right of the central panel. A springy tab catches the handle to reduce risk of inadvertent turning.

"Indoor/outdoor" LCD thermometer below panel infront of copilot (black; difficult to see on photo). Indoor sensor measures cabin temperature; outdoor sensor mounted on one carburetor to give some idea of ram air or carb temperature. (It measures only the surface temperature, not air temp within the throat.) Can be repositioned to check other engine compartment temperatures.

Red object at the base of the canopy to the left is the canopy safety catch. Here it is rotated into place to prevent the sliding canopy unlatching mechanism (with round black handle far left) from being inadvertently slid forward.

Additions since the photo was taken: Van's Aircraft air vents were added, with large eyeball outlets beneath the panel, one each centered infront of the pilot and copilot. Sockets for miniature audio plugs were added above the panel and on the center sub-panel, to be used with a custom cable to connect a handheld GPS to aircraft power.

Canopy spreader gadget - to ventilate cockpit on the ground
Allows the side-hinging canopy to stay open slightly for ventilation on the ground. Avoids the wind stresses on the relatively flexible canopy system that occur if the canopy is left fully open..

Closeup of canopy spreader gadget
It's welded from hinge pins and steel plate (too heavy), with holes drilled for cotter pins to ensure the device does not slide out. As the spreader bar is not a perfect restraint in all directions of motion, the canopy does still flex slightly with the wind.

Tail fairing: A neat little cover for the gap under the horizontal tail
Thumbnail links to two photos, one annotated with the design features.

Installing air vents from Van's Aircraft
The original pseudo-NACA vents (visible in the photo) were placed conveniently at hand, but are in the low pressure area above the wing leading edge, resulting in little airflow. The vents from Van's, complete with hoses and large eyeball outlet vents mounted beneath the instrument panel, are highly effective. An outlet vent in the rear wall of the turtledeck compartment is also important in promoting airflow through the cabin. Zenith recently (late 2000) added drawings of home-made air inlets to their web site, to be placed in the same location.

The vents just fit into the first 'bay' aft of the firewall and below the top longeron. Shown on the wing, from background to foreground: (a) a reinforcing plate that goes next to the skin to provide a load path around the cut-out in the fuselage skin, (b) the plastic inlet, and (c) the innermost 'clamping plate'. This fits over the vent so that the rivets pull on this plate rather than directly on the plastic vent. We built the plates from .025" aluminum sheet. One can install the vent without metal plates, but we wanted to be sure to maintain strength in the area.

Canopy tuft test showing separated flow
Wool tufts show flow separation, and thus increased drag, over approximately the aft 4 to 5" of the canopy.
Tufting at the front of the canopy (no photo here) shows a small area of separation at the front base of the bubble, where it rises too steeply from the fuselage.
The canopy is a standard height Zenith Aircraft Company canopy, with the bubble supplied by LP Aero Plastics.

#1

Not C-GZDC
#2

Not C-GZDC

(1998 photos of
Hans Wallewein.'s aircraft)
Modified canopy hinging system -- On a Zodiac built by the Canadian Flypass dealership
These photos show the "door hinge" style mechanism for side hinged canopies, a builder modification. It may not look as good as the newer forward-hinged canopies, but it is an improvement over the original system. C-GZDC's canopy mechanism is built in a manner to the photos. I copied the basic method from Flypass and from Mike Fothergill, who pioneered the system. Mike uses a more refined system inside the cockpit to slide the hinge pins out. Construction details differ for each builder.

In both photos, right = forward on the aircraft.

Photo #1
Single lugs mount on fuselage, double lugs mount on canopy. Front hinge should mount as far forward as possible yet still clear the canopy front hoop. Aft hinge mounts as far aft as possible, constrained by the need for the two hinges to line up along the cockpit side. Ideally the fuselage widens at a constant rate between the two hinges.
On my Zodiac, the sheet metal side piece at the bottom of the canopy was cut so that there is no more than a millimeter gap between fuselage and canopy. This almost removes any need for a gap seal between the two. But unless the design is changed, the extended side piece will cut into ones hand when lifting the canopy open, as the piece extends below the canopy side rail..

Photo #2
Shows the hinge system from beneath, with the canopy held open. An L-angle forms the structural rail at the side of the canopy, not a tube as in the kit. Bars from the hinge pins extend inwards into the fuselage, where they are joined by an L-angle. To this 'slide' a handle would be fitted. A safety catch should be added to prevent inadvertent activation of the hinge release. My aircraft has a latch that swings down in front of the slide, to prevent it from moving forward to unlock the canopy. The axle for the latch extends to a very small handle on the outside of the aircraft, to satisfy the regulatory requirement for emergency external opening of the cabin.

Not C-GZDC Wing root fairing -- Dave Austin's 601 HDS
Dave created this two piece wing root fairing to reduce drag. It's only one of two I've seen on Zodiacs. (The other one is on Gary Hornbeck's HDS. Pics are on the web somewhere.) I understand that the fairing also reduces buffeting felt from the tail at high angles of attack. Dave, whose aircraft is based in southern Ontario, Canada, did describe the fairing on the Zenith e-mail list at some time. (Photo 1998)

601 HDS sketch -- usable in paint scheme design
The sketch is a digital tracing of a photo of a Zodiac found on the web (N601ZZ).
If it's useful to you, click on the image for a full sized GIF, or do "Save Link As..." (or the equivalent) on the following link to download it: ZDC sketch in Adobe Photoshop (.PSD) format.

> Continue to Page 2b of Construction Photos

Larger version is 86k (1999 with minimal interior)	Instrument panel Features: Shock mounted flight instruments: The standard six except DG replaced by G-meter. (G-meter shows max/min values from trailering the plane to the airport!) The gyro instruments were moved to the bottom row so their longer cases would clear the sloping gas tank. Suction guage mounted close to the flight instruments. 2 axis MAC trim, activated from pilot's stick grip. Both grips have PTT button. Only a single PTT circuit was used; two would have been better, to allow activating only one mic at a time when transmitting. Throttle handles mounted vertically, and low in the panel. This allows the throttle hand to be comfortably rested on or braced by one's knee. Near the throttle are mounted the fuel boost switch (red switch to the left) and the Ivoprop prop pitch control (small black sub-panel beneath pilot's throttle, difficult to see in photo). At top centre of panel: Alternator warning light (as per standard Rotax 912 installation), ELT indicator/switch, EIS master caution light. Engine instruments: Main display is the Grand Rapids Technologies EIS engine monitoring system. Other gauges are manifold pressure, amperage charge/discharge, coolant pressure, and capacitive fuel gauge. Glove box on right hand side, sized to fit pens, sunglasses, etc., and a custom sized flight manual. Central sub panel: Panel kept narrow at the bottom to not interfere with the knees of taller pilots. Radio at the top, and switches below. These include a 6 switch & fuse combination panel from an automotive store. Convenient but cheaper in quality than desired. The Microair 760 radio is inexpensive yet sophisticated. It is small in diameter and in depth behind the panel. The small size can be a disadvantage for viewing and activating switches. The radio also has a simple, non-VOX intercom built in, which is sufficient but not great. Fuel shutoff valve extension is brought from the forward fuselage tank to a point just right of the central panel. A springy tab catches the handle to reduce risk of inadvertent turning. "Indoor/outdoor" LCD thermometer below panel infront of copilot (black; difficult to see on photo). Indoor sensor measures cabin temperature; outdoor sensor mounted on one carburetor to give some idea of ram air or carb temperature. (It measures only the surface temperature, not air temp within the throat.) Can be repositioned to check other engine compartment temperatures. Red object at the base of the canopy to the left is the canopy safety catch. Here it is rotated into place to prevent the sliding canopy unlatching mechanism (with round black handle far left) from being inadvertently slid forward. Additions since the photo was taken: Van's Aircraft air vents were added, with large eyeball outlets beneath the panel, one each centered infront of the pilot and copilot. Sockets for miniature audio plugs were added above the panel and on the center sub-panel, to be used with a custom cable to connect a handheld GPS to aircraft power.
	Canopy spreader gadget - to ventilate cockpit on the ground Allows the side-hinging canopy to stay open slightly for ventilation on the ground. Avoids the wind stresses on the relatively flexible canopy system that occur if the canopy is left fully open..
	Closeup of canopy spreader gadget It's welded from hinge pins and steel plate (too heavy), with holes drilled for cotter pins to ensure the device does not slide out. As the spreader bar is not a perfect restraint in all directions of motion, the canopy does still flex slightly with the wind.
	Tail fairing: A neat little cover for the gap under the horizontal tail Thumbnail links to two photos, one annotated with the design features.
	Installing air vents from Van's Aircraft The original pseudo-NACA vents (visible in the photo) were placed conveniently at hand, but are in the low pressure area above the wing leading edge, resulting in little airflow. The vents from Van's, complete with hoses and large eyeball outlet vents mounted beneath the instrument panel, are highly effective. An outlet vent in the rear wall of the turtledeck compartment is also important in promoting airflow through the cabin. Zenith recently (late 2000) added drawings of home-made air inlets to their web site, to be placed in the same location. The vents just fit into the first 'bay' aft of the firewall and below the top longeron. Shown on the wing, from background to foreground: (a) a reinforcing plate that goes next to the skin to provide a load path around the cut-out in the fuselage skin, (b) the plastic inlet, and (c) the innermost 'clamping plate'. This fits over the vent so that the rivets pull on this plate rather than directly on the plastic vent. We built the plates from .025" aluminum sheet. One can install the vent without metal plates, but we wanted to be sure to maintain strength in the area.
	Canopy tuft test showing separated flow Wool tufts show flow separation, and thus increased drag, over approximately the aft 4 to 5" of the canopy. Tufting at the front of the canopy (no photo here) shows a small area of separation at the front base of the bubble, where it rises too steeply from the fuselage. The canopy is a standard height Zenith Aircraft Company canopy, with the bubble supplied by LP Aero Plastics.
#1 Not C-GZDC #2 Not C-GZDC (1998 photos of Hans Wallewein.'s aircraft)	Modified canopy hinging system -- On a Zodiac built by the Canadian Flypass dealership These photos show the "door hinge" style mechanism for side hinged canopies, a builder modification. It may not look as good as the newer forward-hinged canopies, but it is an improvement over the original system. C-GZDC's canopy mechanism is built in a manner to the photos. I copied the basic method from Flypass and from Mike Fothergill, who pioneered the system. Mike uses a more refined system inside the cockpit to slide the hinge pins out. Construction details differ for each builder. In both photos, right = forward on the aircraft. Photo #1 Single lugs mount on fuselage, double lugs mount on canopy. Front hinge should mount as far forward as possible yet still clear the canopy front hoop. Aft hinge mounts as far aft as possible, constrained by the need for the two hinges to line up along the cockpit side. Ideally the fuselage widens at a constant rate between the two hinges. On my Zodiac, the sheet metal side piece at the bottom of the canopy was cut so that there is no more than a millimeter gap between fuselage and canopy. This almost removes any need for a gap seal between the two. But unless the design is changed, the extended side piece will cut into ones hand when lifting the canopy open, as the piece extends below the canopy side rail.. Photo #2 Shows the hinge system from beneath, with the canopy held open. An L-angle forms the structural rail at the side of the canopy, not a tube as in the kit. Bars from the hinge pins extend inwards into the fuselage, where they are joined by an L-angle. To this 'slide' a handle would be fitted. A safety catch should be added to prevent inadvertent activation of the hinge release. My aircraft has a latch that swings down in front of the slide, to prevent it from moving forward to unlock the canopy. The axle for the latch extends to a very small handle on the outside of the aircraft, to satisfy the regulatory requirement for emergency external opening of the cabin.
Not C-GZDC	Wing root fairing -- Dave Austin's 601 HDS Dave created this two piece wing root fairing to reduce drag. It's only one of two I've seen on Zodiacs. (The other one is on Gary Hornbeck's HDS. Pics are on the web somewhere.) I understand that the fairing also reduces buffeting felt from the tail at high angles of attack. Dave, whose aircraft is based in southern Ontario, Canada, did describe the fairing on the Zenith e-mail list at some time. (Photo 1998)
	601 HDS sketch -- usable in paint scheme design The sketch is a digital tracing of a photo of a Zodiac found on the web (N601ZZ). If it's useful to you, click on the image for a full sized GIF, or do "Save Link As..." (or the equivalent) on the following link to download it: ZDC sketch in Adobe Photoshop (.PSD) format.