What It Does

The Sequenced Gear System improves the stock Legacy system by keeping the inner gear doors closed except when the landing gear is in transit:

• On extension, the inner doors and gear legs go down together, then the inner doors close
• On retraction, the inner doors open, the gear legs go up, then the inner doors close
• Watch the videos

We designed the SGS as an upgrade to the factory kit.  It's simple and reliable, fits within the space constraints of the Lancair under-seat and console areas, and keeps weight to a minimum.  We also worked to minimize cost without compromising our high reliability goals.

Why Sequencing is Important

In the stock landing gear system supplied with the two-seat Lancair kits, the inner doors operate on the same hydraulic circuit as the main gear legs.  Therefore the doors remain extended whenever the landing gear is down.  This arrangement has several unfavorable characteristics:

• The doors and hinges take a pounding from the slipstream and prop blast.   This is a likely factor in reported hinge wear problems on the Lancair 235, 320, and 360 models, and there is a factory Service Bulletin for reinforcing the inner doors on Legacy models.
• Stone chips and other FOD can damage the doors during takeoff.
• Since they are so far forward, the doors may adversely affect yaw stability.
• The inner doors add drag on takeoff, when it is least welcome.
• The open wheel wells cause a large amount of wind noise, and reduce the effective surface area of the wing.
• The open wheel wells can and do accumulate water, slush, dirt, mud and debris.

All of these problems are reduced or eliminated by simply operating the doors independently of the gear legs.  And we do it all using the same reliable technologies as the stock Legacy system.

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