170A Flap Horn

[msweere]

I am having an issue with the flap up-locks on my 170A. It appears that the flap horns are so badly worn at the attachment point that there is too much play to push the lock hook into position. The hardware has been upsized already and the latch is fully adjusted but unless I wiggle the flap it will not lock. My question is, does anyone know if there is a replacement horn available or some type of doubler that can be fabricated to tighten up this sloppy connection. Any advise would be greatly appreciated.

Thanks

[misterde]

The up latch on the C170A does not latch on a regular basis even when parts are new. It is not a good design. I have rebuilt mine which required me to fabricate a flap horn and it worked fairly well for the first year or two with only an occasional failure to latch and then it started to fail to engage more often as time went on. The additional wear was negligible so I have readjusted the mechanism and it will improve but is not dependable enough to rely on. I made some mechanical locks which I use when parked outside and do not depend on the factory latch.

Dick DeCramer
N9007A C170A
Northfield, MN

[Iceman07]

I did a search, and this seems to be the most logical thread....

My mechanic is "concerned" about the up-lock mechanism on my 170A. He says that during the next annual, he wants to rebuild the mechanism.

Here's my thought: The mechanism is badly designed to begin with (as Dick states) and even if it is rebuilt, it probably won't work for more than a year or so. I have aileron/flap gust locks that I use while tied down (they are ugly, but they do work. Anyone know a source for the metal gust-locks?).

So my question is:

If the up-lock mechinism is not working, is this a airowrthniess issue? My gut says no, as it really is to keep the flaps from banging around in the wind, not for flight, but I could be wrong.

What say you, sages of old?

[GAHorn]

I did a search, and this seems to be the most logical thread....

My mechanic is "concerned" about the up-lock mechanism on my 170A. He says that during the next annual, he wants to rebuild the mechanism.

Here's my thought: The mechanism is badly designed to begin with (as Dick states) and even if it is rebuilt, it probably won't work for more than a year or so. I have aileron/flap gust locks that I use while tied down (they are ugly, but they do work. Anyone know a source for the metal gust-locks?).

So my question is:

If the up-lock mechinism is not working, is this a airowrthniess issue? My gut says no, as it really is to keep the flaps from banging around in the wind, not for flight, but I could be wrong.

What say you, sages of old?

Here's some that are offered which are padded:
http://www.aircraftspruce.com/catalog/p ... adlock.php



I do NOT recommend them for rudder-locks as depicted. They should work fine for flaps/ailerons.

The politically-correct answer to your question is: Yes. The uplocks should be operational. (They should not affect safety-of-flight unless severe negative-G's are experienced, and even then it's unlikely to cause a problem.) Many rag and A-model owners tie-down with the flaps fully-deployed to prevent "flapping in the breeze".

[wingnut]

The flap cables having tension on them can cause the uplock to not work. The little spring that pulls the latch hook over the adjustable catch cannot overcome cable tension. Even if the flap is all the way up, and the lock mechanism adjusted properly, and new parts, the little spring can't pull the hook up if there is any tension on the cables. I believe just removing slack from the cables is all that is needed. I watch the latch hook while I tighten the turnbuckles and as soon as it begins to move, I back off a turn.