Repairs, Upgrades and things to look for.

The Smithsonian National Air and Space Museum credits the Laser 200 for bringing about a new generation of aerobatic aircraft
davevon
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Posts: 65
Joined: 02 Sep 2016 05:27
Location: Vero Beach, FL

Re: Repairs, Upgrades and things to look for.

Post by davevon » 11 Mar 2019 08:56

I'm afraid converting yours over to the bronze bushings will not be easy and maybe only possible with the fabric off... There's welding involved on the fixed surfaces and I think your current hinges will have to be cut off. Aviat may be a source for the bronze bushings, but they won't be cheap!

Looking at my bushings they don't look as porous as oilite bronze.

There's virtually no hinge friction with any on my hinges on the ground. I think that under aerodynamic loads with a lack of lubrication or the wrong lubrication you could see significant friction. I think I experienced that with my ailerons on my first flight before doing anything to it. Oiling the hinges improved the centering...

Regards,

Dave
boosted180
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Joined: 30 Nov 2018 12:58

Re: Repairs, Upgrades and things to look for.

Post by boosted180 » 12 Mar 2019 09:00

Dave, is this the STP engine oil treatment you use? If not, can you link me the correct one? The all-purpose grease I used is not good at all. I'm going to take it off and try the STP, but wanted to make sure this is the right one. I also found another cause of the binding/ heavy feeling ailerons and it's due to a slight misalignment of the 3 hinges. I'll post pictures later.

davevon
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Posts: 65
Joined: 02 Sep 2016 05:27
Location: Vero Beach, FL

Re: Repairs, Upgrades and things to look for.

Post by davevon » 12 Mar 2019 17:39

That looks like the stuff. I think Walmart and most auto parts stores carry it. What was wrong with the grease?

Dave
boosted180
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Joined: 30 Nov 2018 12:58

Re: Repairs, Upgrades and things to look for.

Post by boosted180 » 12 Mar 2019 21:15

Ok thanks. I'll get the STP. What do you think of LPS - that's what most mechanics use for lubing (LPS2 I think it is). You think the STP is better?

The grease just didn't feel like it lubricated very well. It's too thick and felt like it added even more resistance. It also attracts a lot of dirt. For comparison, I tried regular motor oil and it felt like it moved much more freely. When I first took everything apart, the bushings had a very gritty feeling when moved against the tubes. It was due to a lot of dirt which was attracted by whatever the previous owners used - probably grease. I know there's many kinds of grease, but at this point, I'm not going reinvent the wheel. If you're saying the STP worked best, I'll just use that.
boosted180
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Posts: 19
Joined: 30 Nov 2018 12:58

Re: Repairs, Upgrades and things to look for.

Post by boosted180 » 12 Mar 2019 21:30

That's a great looking plane Gui! How do you like the way she flies? I like your rudder - it doesn't look like it's according to plans. I was thinking of redoing my rudder at some point with a shape similar to yours. From my RC experience, I know that rudder shape makes a big difference. Ideally the area above and below the elevator should be similar for a more neutral handling airplane and to prevent pitch and roll coupling. This is why the more triangular shape is more desirable. I'd love to see a drawing or dimensions of yours.
Guicensoni
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Re: Repairs, Upgrades and things to look for.

Post by Guicensoni » 14 Mar 2019 04:54

Thanks!!! I’ll search for my drawings and measures and post it here, the plan flys great and it gets better each flight!!!
Take a look at my YouTube channel
And instagran @guixerife for pics!!

Best Regards
boosted180
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Posts: 19
Joined: 30 Nov 2018 12:58

Re: Repairs, Upgrades and things to look for.

Post by boosted180 » 14 Mar 2019 12:00

Wow, that's impressive Gui! You're a very talented builder and pilot!

I found out the MAIN source of the friction and heavy feeling ailerons in my Laser. The three hinges are not aligned. The lubrication and polishing of the tube and bushings made a small difference in comparison to the misalignment. The hard part was figuring out how to check the alignment, especially with not having a laser. So what I did was bought an aluminum tube and mounted it on the wing and using a string, I strung it from the midpoint from the outboard end of the tube to the midpoint on the inboard end of the tube. I did this both vertically and horizontally. Vertical alignment was fine.

Horizontally, the middle hinge is a good 2-3mm too far "in" compared to the inboard and outboard hinges (may be hard to see in the photos). I checked with the ailerons installed two ways - with all three hinges bolted on and again with only the outboard and inboard bolted on. It made a BIG difference to NOT have the middle hinge bolted down (which was very difficult to get on because of the misalignment). With just the outboard and inboard hinges attached, it moved so freely, I could move the aileron with just one finger. So I guess I found the problem. Will try to find a way to re-position the middle hinge this weekend.

After talking to a friend and also doing a bit of reading on my own, it looks like Molykote Z by Corning would be a great lubricant. It's a powder and apparently has an extremely low coefficient of friction and properties perfect for this application. It's expensive though - about $600/ quart from Aircraft Spruce! My friend can get some from work and will give me a bit to use. :D

Here are the photos of the misalignment and also some before and after polishing photos.









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