Over inflating main gear oleos?

[William Flood]

Out today on the field doing lots of little jobs on the Twin. One of the main gear Oleos looked a little down, so we topped the two up with N2. It looks a good bit more than 2.75" so I said to the mechanic to let a bit out. He told me all the pipers sit down over the course of a year and after a few landings the oil and gas will mix and it will settle down.

I know an oleo that's too low can interfere with retraction of the gear. Is the opposite true for an over inflated main?

William

[N3322G]

Edit: Poor reading on my parts - I answered this wrt to the nose gear vs what William actually posted as the main gear.
William, I would translate that as the mechanic didn't want to mess with it. Depending upon how bad it is, IMHO it changes the departure angle of attack. Twin's are pitch sensitive enough already without artificially raising the nose beyond spec. It is the equivalent of putting on a larger nose tire and of course, this is not approved. It can also cause the nose to hit first in your normal landing configuration.

Did the mechanic put it on jacks to make sure it still fit in the gear well without hitting anything? If not, he should, at his expense. It would be you with the in-air emergency if his maintenance has put the nose gear out of spec and it jams in the well.

First, I would use the fuselage area forward of the tail to raise and lower the tail and so, make sure the nose strut is really higher. Remember not to push on the nose if yours is fiberglass. After rocking it a few times, if it is still high, ask the mechanic to bring it into Service Manual spec.

In short, Piper publishes specs for a reason. In my opinion, I'd want my aircraft in compliance - especially the gear.

Just my opinion. Hopefully others will chime in with their perspectives.

[William Flood]

Think the nose is lower as a result of inflating the main Oleos higher. I would have thought that's ok, as the small nose wheel does the same thing without and adverse affects. My own feeling on it is that the gear is fully extended on every pa30 once the weight comes off the wheels.

He didn't touch the nose gear.

Got a few pm s there and the word seems to be no problem on retraction, just less flattering on touchdown.

William

[N3322G]

I was thinking more about the nose gear rather than the mains - less worry there. I read one strut was down and assumed nose - shame on me for not reading more closely.

[Kristin Winter]

By the time you retract the landing gear, all struts are fully extended because there is no weight on them. They are designed to retract when fully extended. So the amount of extension on the ground, has no bearing on the ability to retract, unless perhaps there is no pressure in the struts and hence they will not extend. I am not sure what would happen then.

I routinely keep my mains inflated higher than Piper specs. I do this so that I can easily keep the aircraft on the ground until a safe rotation speed has been reached. I am careful not to raise it so high that the landing gear safety switch is in danger of being activated while taxiing.

[Ray B]

I have always run my 250 comanches a bit above the 2.75 inches on the gear struts for extra prop clearance plus I like the looks of it. It does make for a big step up to the wing for boarding and the older I get the more I think of foregoing the prop clearance and going into dirt strips.---I can't picture a squat switch on my 250, I'll look tomorrow when I'm in the hanger. Ray B

[N3322G]

You mentioned only one strut was down - was it the left? Reason I ask is that was the first indication the left trunnion was cracked was a low strut. Eventually we figured it out and had S&B weld the trunnion. For whatever reasons, the left trunnion seems to crack first.

Something to watch for.

[William Flood]

It was the left one, but I think it could easily be the seals too before I'd worry about the trunnion. I will have it inspected during the week none the less. Is there any guidance on where they normally give trouble?

Edit. Just found it, on Comanche gears website.

Edit 2. I think I have the improved type trunnions.