701 on amphibious floats, Viking 130, DUC 68" PROP.
Condition: wind clm, 29.95, 96°f, D/A 5000'
OP/W app. 1100 lbs.
Normal start, taxi, and runup completed. No abnormalities, all temperatures and pressures were in the noral operrating range.
Takeoff on runway 15 without flaps approxament 300' completed. Approxament liftoff speed 50 mph.
Climb out was performed at approximately 70 mph with 400-500 fpm climb out.
Within 1 minute after takeoff while on the upwind, the gearbox temperature was observed to be 190°f and the coolant temperature was approximately 220°f.
Aircraft was yawed 5 degrees left and right with no abnormal stability found.
Level off was completed approximately 800' AGL and the temperatures did not come down after achieving a 80 mph airspeed and a slight power reduction to 4900 rpm.
A turn to downwind was executed using 15° bank turns. An approach speed was flown at 60 mph to runway 15. A no flap landing was executed with approximate touchdown speed of 55 mph. Aircraft was taxied off the runway and a normal shutdown performed.
Addition notes:
Aircraft handling and stability was good with no noted abnormalities.
During taxi test and high speed test on the runway, all temperatures and pressure were in the normal operating ranges. They took place over two days about 1 hour each day.
A problem found during these test was the brakes became spongy, after bleeding they were good for period of time and then spongy again. After inspection, found there was a leaking brake fitting on both the slave cylinders. OAT in high 90°f on those day's.
DUC 3 blade prop. with blades at 24° pitch.
Static rpm 5250. Prop blades will be set to 23° pitch for the next test flight to reach maximun recommended rpm.
Engine cooling will need tobe addressed with modification to the cowling and radiator shroud.
Gearbox oil was drained and had the recommended 8oz of oil as well as large amounts of silver swirling in the oil. The oil was also very dark in color. A magnet placed in the oil picked up metal chips.
Called Viking and Jan said to ship the gearbox back for inspection and possible repair. After receiving the gearbox, Jan recommended it be replaced with a upgraded gearbox. He shipped it out to me, and it will be install and tested. Stay tuned.

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Interesting analysis on the gearbox. Keep us posted on the upgrade. Good luck on your flight tests. 

If you haven't done so already, test fly without cowl.

Great info, thank you!


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