Posted for Laurie Fitzgerald (laurie@lauriefitzgerald.com):


 Bob... when building the aircraft I realised that a failure of either of the
 flexible lines from the shuttle valve to the main gear rams would result in
 the dual failure of electric and manual system.
 
 
 
 To help overcome this I replaced the 3000psi lines supplied with the kit
 with 25000psi flexible hose and had it pressure tested and certified to
 15000psi I didn't want to test to the full 25000psi and take the system to
 the verge of failure.
 
 
 
 When the system failed I was certain it must have been caused by the failure
 of one of these flexible lines.  I was surprised to find the failed flare
 fitting on an aluminum line but now
 
 realise that the manual pump is merely a backup for an electrical failure
 and in most cases is of little value if an hydraulic line is breached. One
 exception might be the flexible line on the flap system as this is
 restricted and if
 
 you act quickly you may get the gear down.
 
 
 
 My rear carpet is testimony to the fact there was no shortage of hydraulic
 fluid.
 
 
 
 Charlie thanks for the comment on the gas strut. You are correct this was a
 failure or at least an unintended consequence.
 
 
 
 I test the gas strut each 100 hours and it was replaced 120 hours ago. It
 works fine on a retraction test but I guess it couldn't overcome the
 airloads.
 
 
 
 I realise some Lancair IV-P piston powered aircraft are landing much slower
 than me and this may be a factor in deployment of the nose gear.
 
 
 
 On reflection, I am happy to accept the prop and engine damage and should I
 be in this situation again I would prefer the nose gear did not deploy as I
 believe
 
 the stress associated with taking the entire load on the rudder and nose
 wheel would likely over stress the airframe in the region of the baggage bay
 door resulting in compression damage to the
 
 hull.
 
 
 
 Also I believe the wing which takes the load will be more likely to cause a
 ground loop or rupture a wing tank.
 
 
 
 I cannot be sure of the above but sometimes it's better the devil you know.
 
 
 
 Either way in the end it's an expensive Bob sled ride.
 
 
 
 Cheers
 
 
 
 Laurie
 
 

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