Raven wrote:
The initial question was if the plane is OK. And it is. In fact every C172 and 182 has floating windshield.
Yes, all 172/182’s have a floating windshield. However, for my considerable experience with them, what I see in that video is much too much flex in the doorpost frames, I still question if that plane is okay. I suggest that plane should have a really thorough inspection in that entire area, something is not as secure as it should be.
Pilot_DAR wrote:
Bear in mind that the windshield is designed to float in its mounting
You are 100% right. In no circumstances are we going to “block” it from moving.
The initial question was if the plane is OK. And it is. In fact every C172 and 182 has floating windshield.
I just wanted to confirm that due to my limited experience with that type.
Thanks!
Raven wrote:
The severity depends on the windshield either being sealed to to ceiling or left “floating”.
Bear in mind that the windshield is designed to float in its mounting. That is so that the plexiglass does not carry any of the shear load of the fuselage flexing as you see. If the windshield is “sealed” to the fuselage so as to seem to prevent this relative motion, that relative motion of the flexing fuselage will transferred to the plexiglass itself, which is certainly not designed to carry those loads. This could result in a cracked windshield.
If the fuselage was found by inspection to be fine, that’s great, there is no need to seal in the windshield. But if the windshield shifting is a concern, sealing it in, other than by Cessna procedures, is not the solution.
It is noteworthy that a few replacement windshields on Cessna 185’s are bolted to the fuselage across the top as a part of their design. However they certainly float at the bottom (as my 150 does a little). But 185’s are typically cross braced as well….
Problem solved.
In fact the plane is ok. Every Cessna shows this symptoms. The severity depends on the windshield either being sealed to to ceiling or left “floating”.
That particular plane was inspected inside-out.
Thanks for replies!
Pilot_DAR wrote:
this Cessna service bulletin may be applicable
Yes that is the one I recalled, lower doorpost, not upper as I thought
Depending upon the year of this 172, this Cessna service bulletin may be applicable:
https://www.google.com/search?client=firefox-b-d&q=Cessna+SEB95-19
If it is applicable, this is very likely the place to look. If it’s a 172 out of the SB model range, still look in the lower forward doorpost area. The forward doorpost “rectangle” is deforming as a parallelogram. This is “wear” primarily occurring because of lots of rough/grass runway operations, and being loosely tied down, or just chocked in heavy winds for very extended periods.
This plane is probably safe to ferry for inspection/repair, but I wouldn’t call it “airworthy” until it’s confirmed so by inspection. The windshield entirely floats in it’s mounting to it is ridged while the fuselage is flexing around it. I’ve seen this before, and my 150 does it a little bit while taxing on uneven ground, but this is the most extreme I’ve seen.
As a single Cessna pilot, while you taxi any single Cessna over uneven ground, watch the base of the windshield at the glare shield centerline, to see if there is relative motion. There’s usually a little (1/4" or so), but I’ve never seen it at the top before, that’s really loose. You’ll note that all Cessna floatplanes have either a V brace, or cross bracing wires. as seen in this 182 I’m landing in a friend’s lake:
This cross bracing is vital on a Cessna floatplane, as there is no suspension for water landings, and it’s common in rough water for the fuselage to be deflected so as to loosen it this way. The V brace (which I like less than the wires) bolts to the top of the glare shield just over the radios. I’ve seen them loose and slopping around 1/2" during rough water takeoffs. The wires are better, but they cut across the avionics stack, and displace the top radio. Happily, when I had the cross bracing wires installed in this 182, the display of the GTN750 went in front of the wires under the glareshield, so it was a nice fit. If these bracing wires or a V brace were installed at new, this 172plane would not be loose this way.
I’m working on the approval of a repair kit for this problem in 182’s, it would be helpful to me, if the report of the inspection of this 172 could be posted back here…
It is strange to me.
There is no clearance/play between wings and fuselage. The wing bolts are ok.
The whole upper part “the ceiling” of the aircraft (connected to wings) moves together but the lower part with seats stays still.
It is visible even at the back – the ceiling moves left-right above rear seats as well (that was not filmed but confirmed visually).
Anybody owns/operates C172N and can do this test? Just gently shake one wingtip up/down.
Thanks for comments.
Hi! Difficult to tell how much gentleness was being used. There is however significant mass in fuel-filled wing tanks and a decent oscillation can thus be induced.
If this is play, then it has to be fixed ASAP (the live sound should tell whether it is) . If this is deformation in the frame of the forward doorposts and the result of relatively little force, it can be misrigging of the struts or cracking in the fwd doorposts or the wing upper fwd attachment that should be inspected and fixed. If this is the result of significant force then it could be normal. Seaplane Cessna’s use bracing on the fwd wing mount to limit this movement and avoid cracking in the area of fwd doorposts. I am not familiar with the type, but I would not be surprised if there is a Cessna SB to inspect these posts for cracks at a certain location.I seem to recall there was one SB for inspection for corrosion in the upper fwd attachment on some strutted wing Cessnas.
Airborne_Again wrote:
I can see the windshield move relative to the wings, but I can’t see that the fuselage does.
Yes, looks like it. Still kind of odd though ?
What happens on other similar planes?
It doesn’t look good… any movement like this makes a plane vulnerable to aerodynamic oscillation (flutter).
