Hi people

Continued testing the Glasair Super IIRG yesterday with an OAT of 70. See graph of 13 minutes of data (Note: temps in C, Speed in Knots)

Apart from collecting data on the cooling I flooded my system with adrenaline.

On the second run as I hit about 45knots I encountered very high vibration with no warning. I braked and turned of the engine thinking it emanated from the engine/prop.
After leaving the runway and stopping for a few moments I tried a restart, and found all perfectly normal. Previously I had encountered huge missing at rpm so immediately thought that was the issue.
Having wrongly diagnosed the phenomenon I taxied back and did another run seeking to emulate the fault. Well this time I got up to about 47knots and all hell broke loose. 
I was barely able to control her, leaving the strip and into the ruff. Over the radio came the call “if you continue with that front nose shimmy you will destroy your aircraft”. 
Well I had no interest in continuing the testing at that stage but was very thankful for the feedback from someone watching on. With my lack of expertise I had completely failed to realise what was happening.

Back to the hangar and pulled the Shimmy Damper apart. Oil had gotten in at some point, so cleaned it up and re torqued the assembly.

A friend on our airstrip with extensive experience in many different aircraft (he has an RV8, Longezy, jet powered cir cri, Comanche twin) then took it out with me (data not provided) and he confirmed he thought the aircraft seemed very responsive (shimmy Damper a little to tight now) and proceeded to lift the nose off for the first time under its own power at a little over 50 knots.

So some big lessons for me in relation to my expertise and risk profiling.
Temps still concerning but I’m wondering if there is enough capacity to attempt flight testing.
I would appreciate any wisdom that any of you glean from the log data. (I expected a different result from the manifold readings, so not sure what is going on there)

Thanks

Steve Izett
Perth WA - Glasair Super IIRG with Renesis 4 port, RD1C, EM3, EC3