|
|
Wolfgang, Two questions. Have you tested your Module under Thermal Lock with all the configurations of hydraulic systems and pump variations supplied for Lancairs over the years? Which Lancair are you flying or building? Steve Colwell Legacy From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Wolfgang
Sent: Monday, January 28, 2013 11:01 AM
To: lml@lancaironline.net
Subject: [LML] Re: Thermal influence on Hydraulic Pressure Understood . . . but a module like mine doesn't care what version your pump is, it just works. ----- Original Message ----- Sent: Sunday, January 27, 2013 6:59 AM Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure Lancair started adding return springs inside the spool valve for Legacy pumps in about 2005. One of the consequences of doing this is what you have observed in the hangar. You sort of have a 'get out of jail free' card in that your hydraulic system has a three-way valve. It doesn't prevent the lock-up. It just gives you a way out. Folks installing the 'Legacy' pump in 300 series plane with a two-way valve can get stuck. Fortunately the springs are easily removed and Parker has been providing the parts free-of-charge to reset pumps back to the pre-2005 configuration. This has happened to me even at the beginning of a flight, if the temps in the hangar have gone from cold on a previous day, to warm on flight day. I guess cold temps shrink the fluid and suck more from the reservoir into the lines, and when it warms, the pressure builds on both sides of the system, so that the "up" and "down" pressure switches are both open and the gear won't move until I pop the bleed valve. Nasty when the gear won't retract just after blasting off into a low overcast. On Jan 25, 2013, at 7:23 AM, randy snarr wrote: . I dont like having to open the dump valve but it is necessary once in a while especially when it is cold. The pressures on both sides of the system climb due to the engine heat and the gear sometimes will not move without dumping the pressure.
|
|