March 2000

Paint:

The second wing panel and ailerons have been painted.

Panel:

The static line joining the flight instruments  was installed and the sub-panel then plumbed into the aircraft. Connecting the vacuum lines, especially to the Artificial Horizion, required getting in behind the panel which meant lying upside down in the seat and sliding up between the spar and panel. After two hours working behind the panel, sitting properly in the cockpit it now seems quite roomy.

Engine:

In an effort to find the source of the roughness noted in the first test the following was checked...

The head bolts were re-checked for proper torque (those which could be reached). There seems to be no need to check the remainder as no movement was noted. The same was noted on the intake manifold nuts.

Magneto timing appears unchanged and correct.

Valve gap adjustment was found to be a bit too tight. All 4 cylinders were checked and required opening up approximately .003". I am unsure as to why this was required. It could however explain why the engine began to get rough as it warmed up.

On the next test run the engine was run for about 5 minutes. At 1000 RPM the engine runs smoothly but will not idle much below this (hower no attempt has yet been made to adjust this). The engine stumbles as the power is increased indicating it is likely too lean. No oil temp indications were noted on this run. The leads may be reversed.

After the run on inspection it was noted that the intake manifold immediately behind the carb had a thin layer of frost on its outer surface. The outside temperature was 0 deg C and RH was about 60%. I found this interesting but am unsure of wether it should be of any concern.

Baffles:

The cowl will require significant modifications to allow the use of the Q2 style exhaust. Most of the cut outs have been made. Some areas will be re-shaped (bulged) to increase clearance.

The VW conversion presents a few challenges when installing the baffle system. First it is desireable to supply cool air to the underside of the engine even if the oil cooler is mounted elsewhere (as on most non Revmaster types). 

In this case the oil cooler requires a ramping air inlet to take air from the cowl front under the exhaust cross-over and into the area between the cooler and engine bottom. The planform is diverging to increase effectiveness and the gaps in the oil cooler mount have been sealed to create a mini pressure cowl below the engine.

This piece is even easier to make if you have an exhaust system which does not cross in front of the engine as this one does. A weatherstrip on the cowl cut out will complete the oil cooler/pan baffle system.

The cylinders have already had "Super Cool Tin" baffles installed underneath (see April /99). The upper baffle system ties into these to direct as much air as possible around the cylinder and head fins. Since there are no readily available templates for the Revmaster I raided the kitchen for cereal boxes and began making my own.

Note the tie-in plates to the under-side baffles in baffl_08 and the extra cut-out required for the oil filter in baffl_07.

A side trip while in Cuba was to the old Varadero Airport for a sightseeing flight. Three Antonovs, run by the local air taxi service, were sitting on the ramp. These magnificient beasts were still in pretty good shape considering their age.