Eyespy - my Eye in the Sky!

54" Span Pusher Airphoto Platform
Plans Available
Eyespy Video Halifax July 2006
EYESPY simulator model for FMS

Eyespies

The Eyespy has been developed over the past 4 1/2 years as a basic, stable Airphoto platform.

The basic design had to be capable of
1) Low speed flight with the capability of a wide speed range to handle higher wind speeds.
2) Stable flight, allowing the pilot to concentrate on photography and positioning
3) Manoeuverable and capable of landing in small spaces
4) Rugged, but lightweight structure
5) Interchangeable wing, fuselage and tail components
6) Sufficient equipment space, located  at the model CG, to allow variable weight payloads.

WING
A pusher configuration was chosen, with the motor mounted on the wing Trailing  Edge.
Wing structure was based on my long used Free Flight and R/C sailplane structures. This gave a sturdy, springy, light wing capable of taking hard landings without damage.  The wing section was the Eppler 214 undercambered 12% thick sailplane section (fairly thick but efficient).  After the first prototype, subsequent models have reduced trailing edge camber.  Finished wings are strong and light at 5.5 -5.9  ounces finished. 

The first prototype was designed around a Speed 400 motor and at 46" wingspan was a bit underpowered. An AXI 2808/24 brushless was fitted and performance was substantially improved and subsequent models have used 54" wings.  With 10" chord, an area of 520 sq. inches and a wingloading of 9 to 12 oz/sq ft. the model handles well.

FUSELAGE
The fuselage is a pod and boom design and the  construction is a bit unusual, but is not hard to build.  I use basswood
  fairly liberally and I find it to be resiliant and springy. This can generally be replaced with spruce or hard balsa.  

The pod is a horizontal crutch on a carbon boom which supports moulded glass and kevlar shells.  Kevlar is probably overkill and regular glass is more than adequate.  

The "Taco Shell" fibreglass construction is not as complex as it apppears.  Glass cloth is laid up as the "meat" in a flat acetate/glass/acetate sandwich. the sandwich is then wrapped around the balsa fuselage and taped in place. When the moulding is cured, the tape and moulding is removed. The acetate is removed and the glass shell is trimmed and glued on the fuselage frame.  The tail boom is a carbon golf club shaft.

  I have, within the past year, done a revised fuselage pod,  with conventional construction, for those reluctant to try glass moulding.  Both fuselage variations are provided with the plans.

 The newer version was designed so I could mount the camera on a carbon sleeve which slides over the main carbon boom.  This allows the camera to be rotated in a vertical axis to get shots at any angle from horizontal to vertical. The resultant Pod structure is simplified and is much stronger.

TAIL
Tailplane and Fin follow typical R/C sailplane pivoting stab practices.


CURRENT DEVELOPMENT

I have an FMA Co-Pilot installed in the model, but this is in no way necessary. What it does do is provide "hands off" tracking during photo runs, allowing the pilot to concentrate on the photography.

I have recently decided to try an Aileron/Flap version of the wing. This has a flat centre section and reduced tip dihedral.  The wing section for this wing is the SB 11.5 section which is a semi-symetrical airfoil of fairly conventional layout.  This section will result in a higher flying speed than the Eppler 214 (mod) section allowing operation in higher wind speeds. 

The flaps and ailerons will be configured in Sailplane "Crow" mode allowing a combination of "flaps down", "ailerons reflexed" and all moving tailplane incidence increased to provide slow speed landing approaches.  It is not anticipated at this stage to use this feature during photo sessions (but testing may show it to be beneficial).

In summary, I have been very satisfied with this design and have only made minor adjustments and refinements to the original design.  No doubt, things will continue to be adjusted, tweaked and modified over newer versions, but the reliability of the basic design is proven and will be my flagship for a long time.

STATISTICS
 
Wingspan   54"
Chord         10"
Area           520 sq. ins
High Wing Pusher
Model weight (without camera)  35 ozs. (10 oz/sq ft)
                       (with 8 ounce camera)     43 ozs  (12 oz/sq. ft)
Camera fitting (1) 12 deg or 30 deg. downward on left side (or  variable with mount on carbon shaft)
                       (2)  vertically downwards   
                       (3) Facing forward in nose
Motor    Axi 2808/24, 10x5 APC Electric prop
Batteries:  8 to 10 cell KAN 1100 NiMH , or 2100 3s Thunder Power Li-Poly (also have used 3s 3100 Hecell lipoly- good for almost one hour)
 Wing section:  Eppler 214 with reduced undercamber at rear end. This is a wide speed range section with excellent stall characteristics.
Will fly very slowly and is exceptionally stable with hands off capability.
It will climb out at 1250 ft/min when required. (climb rate checked with Lo-Lo Altitude Logger)

Wing construction:
Balsa, built up with  basswood  top and bottom spars with balsa web. Bolt on wing.

Fuselage construction:
Fuselage horizontal crutch with lite-ply formers. Kevlar/fibreglass lower shell and fibreglass upper shells and canopy. These are moulded as wrap-arounds of an acetate/ glass/ acetate sandwich, made up flat and rolled around the crutch, allowed to cure and the acetate removed.  The tail boom is a carbon golf shaft.
Eyespy Mouldings
Glass Cloth laid up between acetate sheet ready for wrapping around structure. Felt pen markings are on outside of acetate and do not remain on glass. Yellow pigment used on glass layup.
Eyespy Fuselage Construction1
Finished mouldings ready for installation.

Eyespy 1/6 full size 3-View drawings in PDF
 
 

 Eyespy Prototype #1

 
  First Eyespy Prototype (Shorter tip panels) cruises past. Removable side panel with hole hides camera.
This model was lost in cloud at 1500'. (only casualty to date).




Plans Price List
Back to Electrikery Page
Home Page