Our L-29 Delfin
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"MAINTENANCE" is a must for continued Airworthiness
A shot of our Delfin as it entered its 12 month inspection. The maintenance program for the Delfin also calls for 50, 100, and 500 hour inspections beyond the calendar inspection.


Note the hydraulic mule for powering the hydraulics. It beats trying to service the gear with that loud jet whistle in the hangar-:>)
   Zweigle Aviation Hangar
The maintenance on the Delfin to this point has been very straight forward. The current manuals that I have were translated to English. While helpful they do leave a few gaps in procedure. In the picture the gear is fully retracted. The gear is manufactured from what appears to be cast iron, and the hydraulics look similar to something on a 580 Case Backhoe! very stout! Flap mechanisms, push pull control tubes, and misc. castings all exhibit superior craftsmanship. The brakes on this aircraft are pneumatically operated drum brakes. That's right, no fluid of any kind and certainly no disks. I have to say, at first the idea of drum brakes did not excite me. However, keep this in mind, most all commercial trucks sharing the highways today still utilize pneumatically operated drum brakes. The reason for this is that the drum brake combination offers a tremendous amount of stopping power. While the drum brakes of the L-29 are a bit more advanced, the physics remain the same.

Zweigle Aviation Hangar cont.
Access to the engine for maintenance requires the dismounting of the rear fuselage. This sounds like a big job, but it is facilitated by the removal of two bolts in the tail surface control rods, A few electrical connections, and eight bolts in the fuselage. With 2 people this can be accomplished in 2 1/2 hrs. All other maintenance can be carried out through the access panels.

As with all other eastern block aircraft the L-29 is made from anodised aluminium. This being the standard in the East as opposed to the Western philosophy of using Al clad materials. The difference being anodising chemically changes the surface to resist corrosion and Al clad is process that puts a thin coat of pure aluminium onto the surfaces for corrosion protection. The exception to aluminium skinning is the rudder and elevators. These have a material that is high in magnesium. Magnesium is a material that will dissolve in water over time so it is not uncommon for these surfaces to show signs of corrosion. In fact these areas are the only ones that corrosion has been exhibited thus far. Beechcraft went through a phase of using magnesium rich materials on tail surfaces also at about the same time. They too suffered corrosion problems.

Flaps are the slotted fowler type having a pitot pressure switch that prevents operation outside the limiting speed of 157 knots, they automatically retract above this speed then extend below this speed if selected. Talking about automatic functions, the air brakes auto extend if the mach limit of 0.7 is reached, and selecting gear up automatically applies brakes to stop the wheels from turning in the wheel wells.

These are but just a few of the many pilot/technician friendly features of the L-29.

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This Bird Is IFR Certified
IFR equipped with Collins Coms, Nav, GS and Markers. King DME. Two place voice actuated intercom. New Garmin Digital Transponder/Enc. and GPS.


Navy HGU 68P Helmet and MGU 14P Oxygen Mask
Our L-29 has also been modified to accept U.S. Personal equipment such as this oxygen mask and communications.