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fibreglass breaks down


floats

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Does anyone have experience withj installaing a new stabilizer. I had to sand the sides of the U to make it fit around the tail boom a according to FD instructions

 

After sanding the sides, I cannot make the stabilizer fit the holes in the support.  The bolts would enter the top but come out outside the metal bracket at the bottom, not trhough the holes

 

FD instructions :

 ·         Between the ribs and the edge of the stabilizer of the minimum allowable size is 10 mm ! , otherwise the rib could be damaged;

·         More focus  can be given to the distance between the fuselage tail and the edge of the stabilizer - 5 mm, strictly adhering to this distance. 

 

2. Check the stabilizer bracket with balancer on visual defects. If everything is OK, you can continue with the installation of the stabilizer. If any defects please send us photos.

3. Install the stabilizer on the bracket, complying previously described distance of 5 mm between the edge of the stabilizer and the tail of the fuselage.

4. Balance the stabilizer so that the angle  as on picture below remained in the aisles range of 0 + -0.5.

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Floats, I've had my stabilator off a few times but have not replaced it so there were no issues with fit on my system.  Trying to understand your comments without pictures.  It appears that your new stabilator's two main mounting holes are located differently than your old stabilator's attachment holes?  Question, is your new stabilator the one with the new 3/4 width trim tab or does this have the older full width trim tab?  I'd recommend that you call Mat at FD USA to see if there is a different main mounting bracket which has different bolt locations for the new stabilator and/or talk to Dave Armando to see if he's installed a new stabilator on an older CT.

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  • 7 months later...

Fiberglass is clear when impregnated, and white when it isn't. There is no fiberglass in these pictures. Yellow is aramid/kevlar, black is carbon fiber. Yes, the core did indeed break down. You might be able to bend and break the damaged portion by hand. Try it (with gloves) to see how much force it takes to break. Then try to do it with the undamaged portion. It should be impossible without some serious tooling.

 

You can do the initial balancing while the stabilator is not installed IAW 4.3.4.4.3, but you need to remove the balancing and mount assembly from the aircraft so you can suspend it from the bracket's axle. That will let you easily get to the balance weight during the initial balancing.

 

Balancing a stabilator is complex, and there's no getting around that. Ailerons, rudders, and elevators are a little easier, because you can use just a simple fulcrum and weight ruler (it looks a lot like the old scales doctors would use, with the little sliding weights).

 

I am installing a new stabilator but I have not done the balancing yet.  As the stabilitor remains in the position where I put it without coming back centre automatically,  I wonder how critical it is to balance it by the book.  Even the original one would stay up if I put it up or in whatever position.  In flight I would guess that the wind would keep it centrered (excluding any trim)

So my question : why to have it so precisely balanced

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Well, I would say to fly without balancing it would make you a test pilot. Might be fine. Might not be.

 

But balancing is important - it does not have to be very far off to be a flutter hazard.

 

Most Conservative Action? Balance it per the Maintenance Manual. If it did not matter, they would not be so specific as to the required balance.

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I am installing a new stabilator but I have not done the balancing yet.  As the stabilitor remains in the position where I put it without coming back centre automatically,  I wonder how critical it is to balance it by the book.  Even the original one would stay up if I put it up or in whatever position.  In flight I would guess that the wind would keep it centrered (excluding any trim)

So my question : why to have it so precisely balanced

 

You must balance it, but you might not need to do it word for word in the manual if you have a functionally equivalent method.

 

Unbalanced control surfaces may flutter in flight, which weakens the bearings and bonding sites. No two control surfaces are alike due to manufacturing deviations (weight AND balance will deviate from part to part), so it is expected to see a line about checking balance in the maintenance logs if a control surface is replaced.

 

Balancing prevents two or more resonate waveforms from syncing. When this happens, they form a positive feedback loop, which means that the amplitudes will feed off of each other and get worse and worse until something dampens them, or you have a divergence, which basically means things break.

 

I don't know too much about the physics behind flutter, but there are books out there about it.

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Speaking of fiberglass and the stains from oil and gas on the shell. 

 

Someone may have noted this before, but a neighbor on the hangar row has a Lancair IV and said the stains are easily removed using isopropyl alcohol.  I had some I was using to clean oil after an oil change on the engine.

 

It worked perfectly.  It will leave a residue if you leave it on for more than a minute or so, but its easily removed using Prolong or any other cleaner suitable for the shell.  It got rid of one fuel stain on the top of the wing, and an soil stain on the nose wheel cowling.

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I have huge fuel stain on the cockpit after a fuel gage tube burst and the tank emptied on the cockpit and the door.  Is using isopropyl ok for the fiber. As I already had my fin and my stabilator melt with rain water, I am very cautious about using anything

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I have huge fuel stain on the cockpit after a fuel gage tube burst and the tank emptied on the cockpit and the door.  Is using isopropyl ok for the fiber. As I already had my fin and my stabilator melt with rain water, I am very cautious about using anything

 

As I just noted in the post above.  I used isopropyl alcohol to remove a fuel stain on my wing today that was at least a month old.  I also used it to remove an oil stain on the nose wheel cowling that was a week old.

 

As Anticept noted, apparently this is safe.  I didn't know it till one of my hangar neighbors who is a home-builder of Lancairs said it was okay.

 

spray some on the stain, wait about 30 seconds.  then use your cleaner (i use prolong http://www.prolong-usa.com/waterless-wash-shine/) and remove the alcohol and the stain.  You may even see the stain run when you spray on the alcohol.  Make sure you clean wide, don't let the alcohol remain on the finish.

 

I also use brake-pad cleaner to clean out the radiator when it gets oil in it after an oil change, and remove that with alcohol.  That tip came from a Lone Mountain mechanic...it cleans the oil better than with just alcohol alone when a lot drips into the fins.

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If you are getting oil in your radiator during oil change from run out after removing the filter, you may want to consider using aluminum foil. It is easy to form a catch pan below the oil filter nipple running down like a funnel into a pan or bottle. Crim the aluminum foil on before you remove the filter. Roll it into a ball when you are finished. You can get this at ACE air products, or Kroger.

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If you are getting oil in your radiator during oil change from run out after removing the filter, you may want to consider using aluminum foil. It is easy to form a catch pan below the oil filter nipple running down like a funnel into a pan or bottle. Crim the aluminum foil on before you remove the filter. Roll it into a ball when you are finished. You can get this at ACE air products, or Kroger.

 

Good idea.  Everyone including the two mechanics that did an oil change on it used rags.  It made a major mess.  I will do that next time....Thanks.

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  • 2 weeks later...

I was expecting this question.  The rods and trim mechanism was weighed and the effective weight was added to account for their effect.  This is not seen in the photo.  The balancing was very straightforward once the stabilator was set into my fixture.

I need to balance my new stabilator.  When I checked it on the plane I had to put a heavy plier at the edge to balance it  which mean that I have to remove the whole mechanism to balance it. The book explains how to reassemble but not how to remove. I removed the two main nuts on each side, I removed the clips but the axle does not come out nor the bearing. I tried to remove the outside plates that carry the bearings but they are secured with bolts that cannot be removed when the whole mechanism is in place.  Also that spring does not seem attached to anything in the back

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post-159-0-30871500-1427407469_thumb.jpg

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I need to balance my new stabilator.  When I checked it on the plane I had to put a heavy plier at the edge to balance it  which mean that I have to remove the whole mechanism to balance it. The book explains how to reassemble but not how to remove. I removed the two main nuts on each side, I removed the clips but the axle does not come out nor the bearing. I tried to remove the outside plates that carry the bearings but they are secured with bolts that cannot be removed when the whole mechanism is in place.  Also that spring does not seem attached to anything in the back

 

Call FDUSA for help. I believe the bolt is actually a carry through rod, and can be knocked out, but don't hold me to that.

 

Those little screws should be left alone if possible! They align the stabilator laterally. They hold down an eccentric cam that moves the bearing up and down on each side. If the stabilator is not aligned, it will have the unwanted effect of acting like a rudder as well. Alignment procedure of the stabilator is also in the maintenance manual.

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The double threaded bolt or pivot pin can be tapped out. The stab needs to be removed first. Leave the screws in the mounts alone. If you need to remove the bearings to replace them then just remove the clips and either pull them out or tap them from the other side once the pivot pin and or the stab mechanism has been removed.

Putting something on the edge while this is mounted on the plane won't show you any thing. To balance this entire mechanism it must be out of the plane.

That spring is so much fun to put in. You'll need to compress the spring and then safety wire it in the compressed state and once in and aligned remove the safety wire.

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The pin has shoulders on it and it may be stuck a little from moisture in the bearings. When you re-install this pin later put a thin film of grease on it to prevent corrosion. You can get corrosion between the pin and bearing inner surface. They are only steel.As you tap on the pin move the balance mechanism up and down to see if an edge is catching.

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I just went through this with the factory.  The pivot pin taps out pretty easily.  They also had me remove the bolt holding the trim bellcrank to the pivot bracket/counterweight, but leave the trim cables on the bellcrank.  That allows the bellcrank to relax, with the cable tension keeping the big scary spring from flying out and taking your face off.

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