Speed Brakes

[craig moodie]

I need some help with my speed brake system on an LNC4

I have a Lancair IV=P with what I think are legacy Precise Flight cable-operated speed brakes. They have worked with no issues for the last two years (since purchasing). Recently on a flight, they failed. I know very little about the system, but after looking them over, I have concluded that the switch on the stick is working. The servo motor is working. The speed brakes deploy when I pull the cables by hand, which leaves the clutch and pully that rolls up the cable and deploys the speed brakes to be the problem. The pullies don't turn much. They turn a little, and then they click and jump. I can't tell if the clicking and jumping is caused by a worn or misaligned gear or an electrical condition causing a solenoid to jump and click.

I can't tell what is causing this or find any good information on the system. There don't appear to be any parts for sale for this legacy system. To diagnose this, I must remove the servo and clutch, which will require me to remove both front seats.

Before I do that, does anyone have any experience with these old-speed brake systems? If I could find a diagram or a good picture of one before removing it.

Thank

Craig Moodie

[Admin]

Craig, do they fail to deploy, or fail to retract? Is it both brakes or just one? I had a speedbrake fail to retract and it ended up being the retract spring.

You can call Precise, but they will push for you to send the controller and boxes in so they can fix and give you a warranty. That will be very expensive.

If you can find the fail, they will sell replacement parts, but they won't warranty anything. That's the option I chose when I had the malfunction.

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[George Wehrung]

Bob Pastusek might have a diagram or schematic of the system.


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