Warbird Information Exchange

I thought I would start a thread to answer some questions I've read on another thread, specifically the hydraulic systems in the F86F model Sabre. The F model Sabre has 3 hydraulic pumps, 2 engine driven and 1 electric powered. The 3 pumps power the flight control systems (normal and alternate) and the utilty system. The engine driven pumps power the normal flight system and utility system. The electric pump powers the alternate flight control system.
The components supplied hydraulics to in the normal and alternate flight control system are the ailerons and the horizontal stab/elevators. The rudder is cable controlled. The landing gear, speed brakes, nose wheel steering and brakes are supplied hydraulics by the utility system. The flaps are driven by electric motors interconnected by a teleflex cable in case one flap motor fails the other can drive both flaps to prevent flap asymmetry.
Failures of any of these pumps leaves you with a few options. I'll try to list a few of them giving the failure and what is lost or what the emergency system could be.
1) Utility system pump failure: no speed brakes, free fall of the main gear and blow down of the nose gear with the use of an emergency accumulator, limited or no brakes depending on fluid loss or residual pressure. Limited or no steering depending on fluid loss or residual pressure.
2) Normal system pump failure: alternate flight pump starts automatically when pressure drops below 700 PSI in the normal system. This pump is cycling depending on demand of the flight controls up to 3000 psi. In our airplane you get a nice bright red light telling you the alternate system is on. There is a manual pull handle that puts the alternate pump into a continuous on mode with pressure up to 4000 psi for the high load demand in the pattern and landing. This system is checked on every start up before flight, both the cycling alternate and the manual alternate. Any one of these fails to work and its a no go.
3) Alternate pump fail: hopefully this is caught before you leave the ground. If not and you have a normal system failure it is time to think about leaving the airplane.
4) Engine failure: Normal and utility pumps inop. Alternate pump kicks on and you have limited control to the flight controls, (aileron, horizontal stab/elevators) and cable rudder control. Looking for a place to land immediately. Manual alternate handle pulled for landing. Emergency gear free fall and nose blow down available. Flaps electric so they are available. Limited if any braking or steering action as these are utility system powered.

Here is a picture of the alternate emergency hydraulic motor and pump.


Here is a picture of the normal and utility pumps mounted on the front of the engine.


My numbers are reasonably close as I don't have the flight manual in front of me as I type this. Sabre pilots please correct me if this information is not correct. The Canadair hydraulics are different than the North American, so I won't even try to compare them.


I hope this helps answer a few questions about the F86 F Sabre hydraulics and what can go wrong and what emergency systems are incorporated. We've looked at the accident reports to evaluate our airplane and where we may need to pay more attention as a precaution.

David
WHF Maint

David,

Thank you for the infomation on the flight systems operation. Looking forward to more on the F-86 Sabre.

Larry

Thanks for the hyd information on the Sabre...

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John Cotter

Thanks guys. I didn't want to hijack the other thread with the F86 for sale, but in light of discussing what may or may not have happened in the Dave Z crash felt I would post what I know of the system in a new thread.

David
WHF Maint

David...... Really nice post.......... I appreciate that. When I met you at Zach's house about 2 OSHKOSH's ago, you kind of confirmed for me that buying an F-86 was about what I thought it was (not a great idea unless I had you to wrench it).


Mark H

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Fly safe or you get to meet me .......

Ditto that! David is about as good as it gets. Now all I need is the rest of the F-86. I have a nose cone....

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"There are old pilots and bold pilots but few old, bold pilots."

i LOVE good info like that! I learn something everytime i log in! well done!

Chris

Thanks guys. This is what it's all about, sharing these in any way that we can. This bird teaches me something new every time I'm around it.

Scott, I guess I'm going to have to come up and wrestle that nose cone from you aren't I?

Thanks again,
David
WHF Maint

I was trying to get it in the back of the Citabria but I think it would ruin the work I did on it.

Any luck with wing tip drawings?

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"There are old pilots and bold pilots but few old, bold pilots."