---------------------------------------------------------- Glasair-List Digest Archive --- Total Messages Posted Sat 05/10/08: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:05 AM - Re: wtb oildyne pump (Bruce Gray) ________________________________ Message 1 _____________________________________ Time: 08:05:04 AM PST US From: "Bruce Gray" Subject: RE: Glasair-List: wtb oildyne pump Careful attention should be placed on testing the emergency down pump/system when the aircraft is on jacks. If you didn't know, the GIII has mechanical uplocks on all 3 gear legs and if hydraulic pressure is lost, they WILL NOT free fall. The nose gear uplock is held in place, against spring pressure, by hydraulic pressure. When up pressure is lost by a leak or turning the dump valve, a spring pulls the uplock open and the nose gear will drop. Hydraulic pressure in the down cylinders from the hand pump is required to unlock the mains. In the older system, without the separate down cylinders, there were some failure modes that left you with no way to lower the mains. Some builders went so far as to install CO2 blowdown systems or run a manual cable from the uplock lever to the cockpit to allow manual release. These issues were resolved in the latest gear system, where the only commonality with the normal extension system is the reserve canister. Bruce www.Glasair.org -----Original Message----- From: owner-glasair-list-server@matronics.com [mailto:owner-glasair-list-server@matronics.com] On Behalf Of darnpilot@aol.com Sent: Friday, May 09, 2008 12:23 PM Subject: Re: Glasair-List: wtb oildyne pump Ah, thank you Bruce. A light went off when you explained the differences. Mine is (I think) correct. See photo. So the bottom fitting is for the emergency pump. Now I see the logic. If the electric pump fails or loses fluid, the emergency system can use all that extra fluid in the canister to pump down the gear. Clever. Jeff View full size -----Original Message----- From: Bruce Gray Sent: Fri, 9 May 2008 11:56 am Subject: RE: Glasair-List: wtb oildyne pump There are 2 ports on the canister. The top one is the fluid return, when you open the dump valve, this is where the fluid goes. The bottom one is the pickup for the emergency hand pump. Yours should be plumbed this way. If it's not then it's wrong. The separate cylinders for the emergency down system were only in the latest iteration of the gear system. Prior to this, the system used the normal cylinders for emergency extension. With the latest gear the output of the hand pump was redirected to the new emergency down cylinders via independent lines. The return line and pickup point of the hand pump to the canister did not change. Bruce www.Glasair.org -----Original Message----- From: owner-glasair-list-server@matronics.com [mailto:owner-glasair-list-server@matronics.com ] On Behalf Of darnpilot@aol.com Sent: Friday, May 09, 2008 11:38 AM Subject: Re: Glasair-List: wtb oildyne pump That may be the way the system works on an airplane with the separate hydraulic down cylinders for the emergency extension, but not on the others. In my plane the hand pump and release valve is the "emergency system". The way the system is plumbed, there is no way to access all the fluid below the pump pickup in the canister, and in my case, its quite a lot. Are you saying the plumbing is different, i.e., different pickups from the pump canister for the emergency down system? Just trying to understand. Jeff -----Original Message----- From: Bruce Gray Sent: Fri, 9 May 2008 11:19 am Subject: RE: Glasair-List: wtb oildyne pump The ports on the canister are installed by Glasair Aviation. The left over portion at the bottom of the can is the fluid reserve used by the emergency gear extension system. Bruce www.Glasair.org -----Original Message----- From: owner-glasair-list-server@matronics.com [mailto:owner-glasair-list-server@matronics.com ] On Behalf Of darnpilot@aol.com Sent: Friday, May 09, 2008 8:06 AM Subject: Re: Glasair-List: wtb oildyne pump Bruce: I did not know that the hydraulic reservoir was proprietary. That said, why is the canister unique? When I serviced the pump on my Glasair III I found that the reservoir held a lot more fluid than the pickups could access, i.e., the pickup only went an inch or two down into a reservoir leaving about 4 inches inaccessible. Is there some logic behind this "proprietary" design? Why cannot a non-proprietary canister/reservoir work as well? It is not a question of cost, more of why? Thanks. Jeff _____ Plan your next roadtrip with MapQuest.com : America's #1 Mapping Site. ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message glasair-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Glasair-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/glasair-list Browse Digests http://www.matronics.com/digest/glasair-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.