A64Pilot

If what you say is true, then the gear collapse on J bar Mooney’s have nothing to do with the locks and there is no need to replace a worn lock. It’s a rigging, not a worn lock problem. If an over center mechanism is over centered enough then a force attempting to collapse the system just tries to force the system further over center. I don’t know if our gear is that far over center or not. I suspect it may not be or there wouldn’t be an issue with J bar down locks, and I believe there is. I believe your first two sentences in the above quote to be correct. On edit, if something didn’t prevent the actuator from being back driven, then it could back off the pressure holding the gear over centered, once past center it will of course collapse bending rods to do so.

I think the NBS works both ways, it seems if it breaks nothing can get the gear down, so it’s used it seems in both directions

That’s been my understanding too, sort of a mechanical Chinese finger trap, free running in one direction, but maybe that’s incorrect? But IF the rest of the retract system is very similar and the J bar requires a down lock to keep from collapsing, wouldn’t the electrical system also require one? If not, why not? I’m not disregarding the overcenter mechanism / springs in this, I think they play a large part as the tubing itself clearly isn’t up to the task in compression all by itself, but it seems that you need both, the overcenter plus something that locks the movement of the tubing. The gear need that spring pressure to keep from collapsing it seems. IF the actuator didn’t have something that locked it in place then that spring pressure could be lost? Again, I’m not stating this as fact, many times I’ve come up with what seems to be logical theories only to find they were way off base because I didn't have all the data, an assumption got me.

I don’t know, good question. It may be a one way clutch like a sprag clutch, allowing free movement in one direction. I’m guessing that the manual gear system and electric system differ primarily in that one is manual and the other has a linear actuator. The manual requires a down lock of the gear can collapse, we know that, so I’m postulating that the electric system requires a similar lock, but ALL this is pure speculation on my part.

Another thought, IF there were occasional shock loads feeding back into the system, like say crosswind landings as @Shadrach has brought up, and the no back spring is what’s absorbing those shocks, that may eventually lead to a no back spring failure? That force is going somewhere.

On the Mooney, if we accept both electric and manual systems have something that functions similarly to down locks, the difference is that instead of being at the gears they are at the actuating end, meaning of course that there are flexible tubes between the lock and the gear. IF there was an excessive force acting on the gear, and the down lock didn’t fail, then the tube is going to bend. That’s pure speculation with nothing but speculation to back it up, but I’ve heard of a couple of mysterious bent actuating rods on this forum. I say mysterious as there isn’t any smoking gun, but something is causing it. Another speculation is that rigging wise, it would have to be grossly out of rig to get bent, flexing sure, but a bend of that magnitude? I think one indicator may be what is the position of the springs? If there isn’t excessive clearance, meaning that the gear is in proper position with the bent tube, then in my mind that points to rigging? If it was properly rigged with a straight tube, then it would have to be loose now with a bent tube?

They don’t, our VR’s are really primitive things, no three stage charging, temp compensation or anything else, just dumb 14 or 28V plus or minus all the time. But then we don’t really cycle our batteries in normal use, starting pulls huge current, but it’s such a short time it discharges a healthy battery very little. The short period of time the Ammeter is high shows that, the battery is recharged usually before takeoff. In truth Auto batteries and ours are constantly overcharged, but obviously they tolerate it rather well. Old Army helicopters that had Ni-Cad batteries we adjusted the VR twice yearly, in spring and fall, it wasn’t much difference I think maybe a half a volt, that was their attempt at temperature compensation. Wet cell aircraft batteries use a higher concentration of acid than automobiles do. I assume that a Concorde VRSLAB battery is the same no matter the label, that’s what I’ve been told anyway. My Engineering contact at Concorde was Skip Koss, who I believe pretty much designed their AGM batteries, but I’m nearly certain he has Retired as that was quite a long time ago and he wasn’t young even then. Concorde is a family owned and run business, or was anyway. If your talking to someone with the last name Godber, that’s the family name. Used to be everyone’s Email addresses were first name@lifeline.com, not Concorde.com. I never asked why

Still I tip toe around corners and don’t take them at speed because long ago I was told because there are no down locks that we were susceptible to side loads possibly collapsing a gear. Likely BS, but I figure what do I have to lose by slowing down to turn?

Didn’t know that. But back to the TEL thing, even if you could get it and knew how much to add etc, that’s not a legal fuel. Plus I strongly suspect should California find out your putting lead into fuel they would punish you severely.

If you put a lazy susan on the plate, then you couldn’t hurt the truss, and you could turn as tight as you wanted too. I think you’re onto something. I think you need to get the plate much closer to the ground, you could do that by placing the wheels axles well above the plate as opposed to under it, that would also allow you to pay like 4” pneumatic tires on it so it would roll easily over most anything

One of my aircraft in my first troop, 85-25454, I remember it because it was a Big Block Chevy. Anyway it’s assigned pilot was real concerned because at high torque and airspeed, it was terribly loud, he thought there must be something wrong with the rotor system, turned out that the window over the pilots head was flattened, maybe due to heat, but anyway at high air speeds the rotor wash beat on it like a drum head. On other aircraft a thicker windshield can significantly quieten them, I should imagine it would quieten a Mooney some too.

I like nitrogen, but being and old tech diver I put tri mix in my tires I like 78/0/21 Honestly the whole nitrogen thing in automobile and little airplane tires is silly. Nitrogen is preferred in Oleo struts because it has no moisture (corrosion) but in little airplanes it’s almost never used with seemingly no ill effects. Big airplanes often use it because of the pressures they are looking at. N2 bottles start at 3,000 PSI so if yiu need say 1650 to pre-charge an accumulator it’s easy with an N2 bottle, tougher with a compressor. Other than wasting your money putting N2 in your tires doesn’t hurt anything though.

Try cleaning and gapping the plugs, only time I had real issues starting my old 540 with a D mag that’s all it was.

Took me a minute to figure out what that was, I was trying to figure out how it could be a valve stem. I just remove the valve stem core, but you know with GA sized wheels we are more likely to damage the wheel than ourselves. ‘Not saying don’t be concerned, just I think those big Commercial wheels at the pressures they run likely contain 1000 times the energy.

Now that I think about it, are Commercial valve stems rubber? How could they be cut off if not? I’m pretty sure the ones we had on the helicopter were metal. We had tubeless tires so the valve stem was mounted into the wheel half and sealed with O-rings, had a nut on the outside