Advice from C152 engineers needed
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From: UK
Advice from C152 engineers needed
Hopefully you can help with a couple of questions I have regarding some points on a Cessna 152.
I had a problem with the dooe opening whenever the aircraft was pitched up or down with any kind of zeal. Although I am talking about maybe 1.5 or 2g. Any thoughts on why this is happening would be good.
Also one of the up going ailerons does not go up anywhere near as much as the other up going. Actually, It seems the angle on one of them is low as I find in hard to get my fingers between the wing and control surface whereas there are no problems on the other side.
If you could shed any light on this, thanks.
JTK
I had a problem with the dooe opening whenever the aircraft was pitched up or down with any kind of zeal. Although I am talking about maybe 1.5 or 2g. Any thoughts on why this is happening would be good.
Also one of the up going ailerons does not go up anywhere near as much as the other up going. Actually, It seems the angle on one of them is low as I find in hard to get my fingers between the wing and control surface whereas there are no problems on the other side.
If you could shed any light on this, thanks.
JTK
Joined: Dec 2006
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From: belgium
Sorry cannot help you, but that door opening is typical cessna I think. On most c152's the doors have a gap of about 1cm, wonder why that is. I've had the door opening in flight several times. Especially on take off it can be disturbing when the door opens. The door lock does get worn if you just slam the door closed on ground; I made myself the habit of pulling the door handle out, then close the door and close the door handle again and give it a good punch before take off to check if it stays closed.
Conserning the ailerons, I also found that all c152 were feeling different from other c152's. On some you could get more than 180° wheel travel while ailerons only followed in the 180° range, on others you turned the wheel, but the first 5° the ailerons didn't move at all. It depends on wear and age I guess. Nothing really bad.
Conserning the ailerons, I also found that all c152 were feeling different from other c152's. On some you could get more than 180° wheel travel while ailerons only followed in the 180° range, on others you turned the wheel, but the first 5° the ailerons didn't move at all. It depends on wear and age I guess. Nothing really bad.
Joined: Feb 2006
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From: Station 42
It's been a while since I worked on a C152 but you might like to check the following:
Remove the lower wing panel forward of the aileron operating rod and look at the cable-operated bellcrank. You'll see that it has kidney slots in it and the extremities act as stops in conjunction with the sides of a sleeved pillar bolt. Does the bolt make contact at both ends of the slot? It's highly unlikely that it doesn't however.
Secondly, look at the operating rods themselves. Are they bent? This is reasonably common if the control lock hasn't been fitted and the ailerons have been blown around in the wind. A bent rod will limit the control movement.
Re the door - have the latch mechanism checked on the next inspection, along with the aileron range of movements.
Hope this helps.
Remove the lower wing panel forward of the aileron operating rod and look at the cable-operated bellcrank. You'll see that it has kidney slots in it and the extremities act as stops in conjunction with the sides of a sleeved pillar bolt. Does the bolt make contact at both ends of the slot? It's highly unlikely that it doesn't however.
Secondly, look at the operating rods themselves. Are they bent? This is reasonably common if the control lock hasn't been fitted and the ailerons have been blown around in the wind. A bent rod will limit the control movement.
Re the door - have the latch mechanism checked on the next inspection, along with the aileron range of movements.
Hope this helps.
Thread Starter
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From: UK
stevef
Thanks very much.
I must point out that I am a lowly FI, which means I know an awful lot less than I think I do about engineering.
Useful though and I will ask engineering here to show me those parts on the aircraft when its in.
Thanks again
I must point out that I am a lowly FI, which means I know an awful lot less than I think I do about engineering.
Useful though and I will ask engineering here to show me those parts on the aircraft when its in.
Thanks again
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From: Falling off the end of the thread
Ok as for the aileron range, this is as said set by a kidney shaped slot on the bellcrank where the aileron rod attaches to the cables bellcrank, the range should I think off the top of my head plus or minus 1 degree.
As said check the rod for being bent where it comes out of the wing and connects to the aileron......
If all is ok and the range is about right there is the possibility that the aileron has been adjusted on the rods lengths.... this is done if you have an aircraft that is flying slightly out of level, by adjusting the rod end to max range you can lift that wing and make it fly straight and level, so you could have a difference of about 2 degrees from each other......
Put the ailerons in the neutral position, ie controls wheels level across their tops and and check the position of the ailerons against the Flaps, NOT the wing tips...... they should either be level with the trailing edge or both drooping slightly about 1/2 a degree dependant on the year of the aircraft...... if there is a difference, ie one is slightly higher or lower then I would say they have been adjusted to get the aircraft to fly level...... I am taking it on a still day the aircraft does indeed fly level.......
OK now your door. yes this can be as said a worn latch mechanism. this is a megga expensive item BTW.... things to check are is the thing lubed? if not lube the toothed roller and also the doors grooved latch that pokes out, indeed lube the door mechanism as much as you can, they can stick or bind against the door trim so they do not fully extend out.....
next thing to check. on the upper part of the door frame on the front, you will see a little plate with a rolled over lip about 1/2 an inch in size and held on with 2 screws, looking at the fwd edge of the door you will also see a projection that sticks out and when the door shuts it sits behind this lip..... if this is not pulling in the top of the door or indeed sitting close behind it it allows the door to flex and pop open, see if their are witness marks on it where it was screwed on before and whether it has moved. adjustment to that, ie moving it inboard slightly can normally sort this problem out........
ok, off the top of my head, last idea. the door frame has some little pieces of ally that is riveted to it and then to the frame, these sometimes crack and allow the frame to twist slightly..... push the plastic cabin trim in at the back of the door frame slightly and you will see them, just check they have not cracked........... hope that helps,
How are the door hinges BTW? another stupidly priced item, about £300 EACH!!!!!!!!! thats per hinge not two...
As said check the rod for being bent where it comes out of the wing and connects to the aileron......
If all is ok and the range is about right there is the possibility that the aileron has been adjusted on the rods lengths.... this is done if you have an aircraft that is flying slightly out of level, by adjusting the rod end to max range you can lift that wing and make it fly straight and level, so you could have a difference of about 2 degrees from each other......
Put the ailerons in the neutral position, ie controls wheels level across their tops and and check the position of the ailerons against the Flaps, NOT the wing tips...... they should either be level with the trailing edge or both drooping slightly about 1/2 a degree dependant on the year of the aircraft...... if there is a difference, ie one is slightly higher or lower then I would say they have been adjusted to get the aircraft to fly level...... I am taking it on a still day the aircraft does indeed fly level.......
OK now your door. yes this can be as said a worn latch mechanism. this is a megga expensive item BTW.... things to check are is the thing lubed? if not lube the toothed roller and also the doors grooved latch that pokes out, indeed lube the door mechanism as much as you can, they can stick or bind against the door trim so they do not fully extend out.....
next thing to check. on the upper part of the door frame on the front, you will see a little plate with a rolled over lip about 1/2 an inch in size and held on with 2 screws, looking at the fwd edge of the door you will also see a projection that sticks out and when the door shuts it sits behind this lip..... if this is not pulling in the top of the door or indeed sitting close behind it it allows the door to flex and pop open, see if their are witness marks on it where it was screwed on before and whether it has moved. adjustment to that, ie moving it inboard slightly can normally sort this problem out........
ok, off the top of my head, last idea. the door frame has some little pieces of ally that is riveted to it and then to the frame, these sometimes crack and allow the frame to twist slightly..... push the plastic cabin trim in at the back of the door frame slightly and you will see them, just check they have not cracked........... hope that helps,
How are the door hinges BTW? another stupidly priced item, about £300 EACH!!!!!!!!! thats per hinge not two...
Joined: Jun 2002
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From: UK
The ailerons on a 152 should both be the same (1/2 or 1 degree of droop IIRC from the flaps) - there is NO allowance (unless the book has been rewritten very recently) for off-setting them in the Maintenance Manual for a heavy wing situation. On the 152 this is cured by reducing the angle of attack on the light wing by turning the rear spar attachment bolt eccentric bush.
152s will fly wing heavy with only one person on board (who is sitting on one side, not in the middle!).
On the Pipers you are allowed to cure a heavy wing situation by dropping a flap.
Some times the small door frame stiffeners crack which beef up the rear edge of the fuselage door frame which allows the frame to flex more than it ought to.
Because of the rotating latch mechanism, you have to make sure the door is properly closed (not wishing to teach you to suck eggs here). From the outside that's easy - a firm push on the door adjacent to the lock does it. From inside it is often difficult to get enough pull on the door closing strap to shut the door properly, best way then is to open the window and pull on the window frame towards the back of the door.
Another possibility is a door seal out of place that is preventing the door closing completely - either at the front or rear edge.
Interesting that on a 172 you can't open the door from the outside once it's locked for flight from the inside - not good if the RFFS people are trying to get people out in a hurry....
152s will fly wing heavy with only one person on board (who is sitting on one side, not in the middle!).
On the Pipers you are allowed to cure a heavy wing situation by dropping a flap.
Some times the small door frame stiffeners crack which beef up the rear edge of the fuselage door frame which allows the frame to flex more than it ought to.
Because of the rotating latch mechanism, you have to make sure the door is properly closed (not wishing to teach you to suck eggs here). From the outside that's easy - a firm push on the door adjacent to the lock does it. From inside it is often difficult to get enough pull on the door closing strap to shut the door properly, best way then is to open the window and pull on the window frame towards the back of the door.
Another possibility is a door seal out of place that is preventing the door closing completely - either at the front or rear edge.
Interesting that on a 172 you can't open the door from the outside once it's locked for flight from the inside - not good if the RFFS people are trying to get people out in a hurry....
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From: Falling off the end of the thread
The ailerons on a 152 should both be the same (1/2 or 1 degree of droop IIRC from the flaps) - there is NO allowance (unless the book has been rewritten very recently) for off-setting them in the Maintenance Manual for a heavy wing situation. On the 152 this is cured by reducing the angle of attack on the light wing by turning the rear spar attachment bolt eccentric bush
Last edited by NutLoose; 21st January 2007 at 15:25.
Joined: Jun 2002
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From: UK
Nutloose - Apologies, I misunderstood your post, I thought you implied that aileron misalignment was allowed to correct a heavy wing. Good point about the bent operating rod.
Barit - hard to mismanage the 152 fuel system: Off or On and two linked fuel tanks! Of course, fly it out of balance, blocked vents, restricted outlet pipes etc etc and it may be different left to right.
Barit - hard to mismanage the 152 fuel system: Off or On and two linked fuel tanks! Of course, fly it out of balance, blocked vents, restricted outlet pipes etc etc and it may be different left to right.
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From: Falling off the end of the thread
