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dannparks
Sergeant Major
Gender: Male
Location: Parkside Airpark, Battle Ground, WA
Registered: Oct 2006
Status: Offline
Posts: 391
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 Posted Sunday, October 20, 2013 @ 05:56 PM
If engine issues aren't enough, I now have a loose (wobbly) horizontal stabilizer. My fault entirely. I had lifted the tail to drain the oil and it fell off the box it was sitting on and the stabilizer landed on the box on the way down. The impact seems to have loosened the attachment bracket inside the stabilizer -- probably elongated the bolt holes that hold it, the parts catalog shows that there are two bolts inside holding it. The result is that the stabilizer can be wobbled a bit if you pull it up and down. The motion at the bracket is very small, but it is exaggerated to about 1/2" at the tip of the stabilizer.
I know it's not good to have loose control surfaces (potential flutter), but before I try to fix it, I'm curious if anyone has a stabilizer that has loosened over time. I imagine these brackets do loosen over time and some play might be expected.
Fixing it will be a bit of a pain, so I'm just getting some info and advice from the group.
Thanks.
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Dann Parks • RF4D #4051 N2188 • now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
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Markku
Master Sergeant
Gender: Male
Location: Kouvola, Finland, EFWB
Registered: Oct 2006
Status: Offline
Posts: 167
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Posted Monday, October 21, 2013 @ 01:02 PM
Hi Dann
It's quite normal, we have tighten the bolts in OH-370 and OH-380, and in overhaul I took those fittings off for checking. You have to make an opening above the fitings to take them off, and check the bolts. I can add some pictures later.
Markku
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Donald
Command Sergeant Major
Gender: Male
Location: Scotland
Registered: Jan 2007
Status: Offline
Posts: 489
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Posted Monday, October 21, 2013 @ 02:03 PM
Dann from your description of the accident I'd be concerned that you might have damaged something significant in the wooden structure of the stabilizer. There is a fairly well known incident here in the UK of a Robin, another French wooden wonder, that went off the runway and the left wing rode over a large hay bale. No damage seemed apparent but the wing came off on the next flight! If I recall correctly the ride-over put a compression crease in the spar top boom.
I'm not trying to alarm you but after what you describe I think I'd want to be sure that the stab was not compromised at all. Just sayin'.
Donald
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dannparks
Sergeant Major
Gender: Male
Location: Parkside Airpark, Battle Ground, WA
Registered: Oct 2006
Status: Offline
Posts: 391
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Posted Monday, October 21, 2013 @ 02:23 PM
Thanks for the info. Luckily the hit wasn't that hard, but it is important to go inside and take a look at what has gotten loose. I suspect it is elongating of the holes in the wood, but the rib might have cracked as well.
Markku, if you could post some pictures of the size and placement of the openings, and maybe what to expect inside, that would be great.
And the procedure for covering the openings back up.
Thanks.
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Dann Parks • RF4D #4051 N2188 • now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
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jb92563
Second Lieutenant
Gender: Male
Location: Lake Elsinore, CA, USA
Registered: Mar 2007
Status: Offline
Posts: 583
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Posted Tuesday, October 22, 2013 @ 03:55 PM
I had a slightly loose stabilizer a ways back and being a wood structure it was attributed to some wood fuselage shrinkage in the Dry California air.
After a year the Southern California open air covered storage was dryer than a Phoenix Arizona Hanger.
I was able to tighten the bolts on the "L" brackets by reaching inside through the rudder cable exits, which are round inspection plates with a cable slot cut in it, in my case.
[Edit by jb92563 on Tuesday, October 22, 2013 @ 04:00 PM]
[Edit by jb92563 on Wednesday, October 23, 2013 @ 07:42 PM]
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Ray
RF4D #4057 N-1771 Rectimo 1400cc
http://picasaweb.google.com/jb92563/FournierRF4D
http://www.touringmotorgliders.org
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Markku
Master Sergeant
Gender: Male
Location: Kouvola, Finland, EFWB
Registered: Oct 2006
Status: Offline
Posts: 167
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Posted Wednesday, October 23, 2013 @ 03:29 AM
Hi Ray and Dann
Unfortunately the problem is in most cases the fittings inside the stabilizer, fittings in the fuselage are easy to adjust due to rudder cable opening.
Attached few pictures of the cutted opening, and fitting connection to stabilizer wood structure
Markku
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dannparks
Sergeant Major
Gender: Male
Location: Parkside Airpark, Battle Ground, WA
Registered: Oct 2006
Status: Offline
Posts: 391
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Posted Wednesday, October 23, 2013 @ 10:25 PM
Thanks for the photos Markku. It looks like an easy repair if you make the holes large enough to turn the wrench. How did you stop the looseness? Larger bolts? A filler sleeve?
Since I will need to patch the fabric, I think I'll go in from the bottom which should make the patch less visible. And I only need to do one side.
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Dann Parks • RF4D #4051 N2188 • now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
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Markku
Master Sergeant
Gender: Male
Location: Kouvola, Finland, EFWB
Registered: Oct 2006
Status: Offline
Posts: 167
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Posted Thursday, October 24, 2013 @ 04:55 AM
Hi Dann
In our cases it was enough just to tighten the nuts, stabilizer main ribs obviously have shrinked a bit
Markku
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Bob Grimstead
Captain
Gender: Male
Location: Perth, Western Australia or West Sussex, England
Registered: Dec 2006
Status: Offline
Posts: 2028
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Posted Sunday, October 27, 2013 @ 01:29 PM
Hi again Dann,
As a precaution, a few years ago Matt & I opened up and inspected the horizontal stabilizer fittings on 'WGN, 'WEF & HDO.
We cut three small circular holes in the undersides, and then scarfed in circular plates and covered them with fabric patches afterwards.
We didn't actually find any shrinkage, ovalised holes or corrosion of the steel fittings on any of them -- all these were things we had been worried about -- even in the hot, arid air of Western Australia.
So I would be very careful about what you inspect and what is causing that looseness Dann. I suspect that something wooden is actually cracked.
It's heartbreaking to have to cut through new fabric and a recent, flawless finish, but nothing on any RF design is any bigger or stronger than it absolutely has to be, so you need to be absoultely certain that it is all perfect before you fly again.
I hate to be so gloomy, but if you don't inspect and fix absolutely every suspect component, you will never enjoy flying your beautiful Fournier. And I say this as somebody who is right in the middle of doing the same thing.
My 'quick re-cover and respray' has turned into a bigger epic than Ben Hur, worse organised than a Lebanese goat-roast, but in the end (whenever that will be!) it will be worth all the grief and expense.
It bloody well had better be worth it anyway. I've aged ten years in this past fortnight!
Yours, Bob
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Bob Grimstead
Captain
Gender: Male
Location: Perth, Western Australia or West Sussex, England
Registered: Dec 2006
Status: Offline
Posts: 2028
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Posted Sunday, October 27, 2013 @ 02:00 PM
Have you seen / did you remember this thread?
http://sbeaver.com/cgi-bin/fournier/cutecast.pl?session=6iwRVDOLeDBW9R8leics6ITtBA&forum=11&thread=694
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dannparks
Sergeant Major
Gender: Male
Location: Parkside Airpark, Battle Ground, WA
Registered: Oct 2006
Status: Offline
Posts: 391
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Posted Tuesday, October 29, 2013 @ 11:14 PM
Well I opened up a small hole on both sides of the bracket and there was nothing cracked or broken inside -- or excessively ovalized holes. The bolts were surprisingly loose after all these years (as Markku mentioned). I tightened them up and the looseness in the bracket is gone. I think that I will take the opportunity now to open up the other side and tighten them too. Thanks for all the help and photos.
I did find something odd about the bolts in the brackets though (new thread -- pun intended).
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Dann Parks • RF4D #4051 N2188 • now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
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