Cricri aerobatic aircraft and other complex projects Page
Finally it looks like an aeroplane.
All the SAA mates around for a Sunday evening meeting. I put the parts together for the purpose.
Fitting out the Fuselage
Bit by bit dozens of small parts have been fabricated since joining the fuselage halves in May 06. Fuselage stiffeners glued in place. Bits made - seat, seat back, pedal tray, 4130 stick mount and elevator initial control, all levers, throttle control, latches, canopy hoops, noseleg - each item taking a few evenings. Its all part of the hobby.
Front and Rear Turtledeck frames
First effort to bend the sheet Ali over customwood jig completely failed - split. Not happy with the appearance. Seeing many worn klegecell pieces in the web photos I decided to have a shot at making then with fibreglass over klegecell, cutting the 20mm klegecell in two pieces and bonding together before glassing. Wrapped with glad wrap for smooth surface. Also a novel throttle cover out of carved 20mm Klegecell, slightly curved on top and fitting snuggly. Same technique as canopy frames. Didn’t work well—needing several layers, lots of sanding—twice the time for plans technique.
The first effort at bending the seat frame just split the tube, using a commercial pipe bender. Then made my own wheels on the lathe, and home made bender. This worked OK with tubes filled with fine constructors sand that we happened to have lying around for filling between path bricks. Third go at seat back worked. With patience the hoops came out OK but a little lumpy
Shimano Deore hydraulic Disc brakes and wheel hub mods
Wheel hub adapters to mount the rotor are "petal" shaped so I had them CNC fabricated by Matthew Connor. I purchased one brake lever, two rotors and calipers + oil and brake hose from NZ internet supplier.The 5/8 steel tube axles I machined slightly too loose after welding threaded plugs into ends ( the weld made the lathe judder and cut too deep) Had them metal sprayed by Connett Engineering, and machined again —perfect.
The photo shows the petal shaped adapter. In theory the securing screws should be loose to allow the rotor to float, but I found this unnecssary.
Many, many parts fabricated. Clevis’s done on lathe and mill—quite good. Welding of the metal parts by Errol Rolston is a bit rough so some redone by Graham at Connett ($500). Control stick made from 3/4 in 2024 with 80 x 17 x 1 mm joiner turned from free machining Ali—bonded and riveted.
Cut out in custom wood and plywood discs to represent instruments. Using the small Dynon gives everything I want. Panel to be fibreglassed to give some shape to the unit, instead of rear bracing. Hinge system modified as it wont clear Radio and Dynon when hinged.
Heavy fuel valve setup—to be machined down or find Nylon valves.
The rudder pedal tray as I have set it up, is not able to be adjusted in flight, but spikes on the plans version are avoided by my modified system
- sprung levers into each rail that locate into guide holes.
Forward and rear canopy hoops need to be attached somehow.
Vertical tail web rivets can be set ‘backwards"— as it is difficult to set them conventionally within limited space. At least they are in shear only.