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Just wanted to do a quick straw poll as to what TAS people are getting
from
the LNC2?
Does everyone have the standard Lancair pressure switches installed?
How often does the gear motor do a brief cycle whilst (a) on the ground or
"down & locked" and (b) airborne
On a normal cross country -- carrying a passenger and a little baggage -- at 11,500, WOT, 2400 RPM, I usually get 187 to 189 TAS. If I open the ram air and go to 2500 RPM, I can get about 193 TAS at the same altitude. I have an IO-360 with 9.5:1 pistons and the MKII tail. After two years of flying in primer, I have been working on painting the plane over the winter and hope to get a couple more knots with the smoother finish. I'll find out in a couple of weeks when I finish putting the plane back together.
I have the standard pressure switched -- the ones that were supplied with the kit back in 1997. I usually get one burp of the up cycle at altitude after about 45 minutes or so as the fluid cools and contracts. For the down cycle, the pump comes on for a short burp only if the plane has been sitting for several days, or if the ambient temperature is significantly cooler than when I last powered up.
One interesting thing I have noted on my plane is that the pressure-relief-valve setting has a significant hysteresis -- at least on the down side of the system. I installed pressure gauges on my panel, so I can easily monitor the system pressure. When I set the low-pressure pressure switch, I can verify that the pressure-relief valve is set to about 550 to 575 psi ( the pump keeps running -- fluid being dumped through the relief valve.) On a hot day, however, I can watch the down-side pressure gauge go well above this pressure, to about 800 - 900 psi, as the fluid heats up and expands. If you hit the relief setting hard, the valve opens at the 550 to 575 setting. However, if the pressure increases very slowly, the valve does not open until you reach a much higher pressure.
Mike Reinath
LNC2 N3602M
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