Look Ma - No Flaps

[Geoff]

Having built a Jab myself I don't believe that can happen

 

 

[motzartmerv]

Really??...why not...please tell me there's some mechanical mechanism that would prevent this from happening..

 

cheers

 

 

[Geoff]

To the best of my knowledge there is no way this can happen (1 side of his flaps retract while the other side stayed stuck down...) if one side became disconnected to the other i.e. mechanical failure, air flow would return the flap to the negative position. If you fly a manual flap Jab and don’t put the handle in the detent position positively the flaps will retract all by them selves. I can think of no scenario where one flap could stay deployed.

 

Perhaps you could explain how?

 

 

[motzartmerv]

Ok...ill track down the guy who had this happen...as i said, i heard it from a guy who knoew the guy...ill suss it out and get back to ya...

 

cheers

 

 

[Guest brentc]

I'm confident that a condition could exist where one flap stayed down and the other one came up and vice-versa. The flap actuating arm could bind on the fibreglass fairing causing it to freeze up, plus if the bolt broke or came out of the actuating rod it could put them into a situation where they are in different positions. Stranger things have happened I'm sure.

 

More importantly if you're pre-flighting your Jab, is to check the security of the aileron cable mounting bracket in the perspex window at the outer end of the wing. I have seen one of these come loose on a factory aircraft which would result in an inoperative aileron.

 

 

[Geoff]

I'm confident that the fiberglass fairing is not Strong enough to stop the flap from retracting from the force of air flow nor stick down if a bolt broke or came out, strange things do happen like nylock nuts coming undone

 

 

[lark]

have heard of it happening with a c172 though. definately not a good situation to be in!

 

 

[deadstick]

This is a common problem mate, in my experience it is always in the motor, the commutator rings get dirt. If it stops working give it a hit and it will go again. Go here:- http://www.jabiru.net.au/Manuals/Aircraft%20Technical/JTM001-1_Generic_Tech_Rev1_signed.pdf#page125

 

Page 127, shows the problem, never had a switch fail to work, they stick but rarely fail.

 

 

[ianboag]

My 160 did that a couple of years back.

I took off the flap motor, disassembled it and cleaned the brushes/commy. As I recall getting it off was not enormously hard.

 

The diassemble-clean-reassemble-test took a good chunk of one evening. No problems since.

 

Sorry I didn't see this thread a bit earlier as starting with the motor might have saved you some time .....

[Keenaviator]

yea cool.. wasn't sure.. Is it only under load it plays up??...i worry beacause ive heard a of a guy having 1 side of his flaps retract while the other side stayed stuck down...

Aren't the flaps of Jabies locked into the same position as each other on a chromoly torque tube? Mine are. I suppose if a rod end failed or an4 bolt sheared this could happen.

 

 

[Bruce Tuncks]

Some years ago John Canard died when one flap of the HP14 glider he was flying let go and he was too close to the ground to save the situation.

 

If he had been quick enough to release the other flap he could have lived.

 

Then I saw a Grob glider on landing do a vicious yaw because on opening the airbrakes, one brake flew to the fully-open position. this was quickly countered by a smart pilot who opened the other one to match.

 

So if that Jabiru thru-shaft ever fails, release the flap lever to the up position.

 

I reckon a failure here is very unlikely.

 

Bruce

 

 

[facthunter]

What Bruce says is correct. Unlikely doesn't mean cannot. Anything mechanical can malfunction. Flap/ spoiler assymetry is possible and can cause control difficulties (even loss of control). Setting the flap to correspond with the damaged one's position is required. Sometimes spoiler float can only be counteracted by displacing the control wheel a large amount and your new "neutral" may be with the wheel at 90 degrees to horizontal. This is an "abnormal" situation rather than an emergency but you should know how to deal with it. You have loss of control capability, if some displacement is needed to keep the ship level and a possible change required to your approach speed. Nev