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IBob

Savannah S Build Notes - Flaperons

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Comments and suggestions welcomed. Always.

 

Some Prep:

 

As with the wings, the rib noses can raise a mark in the skin at the leading edge. On the flaperons, this is a tight curve, and I found it worthwhile to spend a few minutes with file, emery and scotchbrite on two potential high spots. While I was there, I also rounded and rolled the very front of each nose rib.

 

I also used the same block I used on the wing ribs to square the edges of the triangular rear ribs.

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Next, how NOT to do it:

That's a picture of the RH inner assembly, and you can see I have riveted the inboard end rib...closest to the camera...in place.

 

No part of this rib should be riveted at this stage (although the little bracket that mounts it must be riveted to the spar).

I subsequently found it easiest to cleko the rib until the flaperon was built and skinned, then sort out the necessary riveting sequence for the parts that attach on and around this rib.

Which isn't complicated, I just didn't see it coming...

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Next, skin and clekos and rivets. A nice use for those ICP straps.

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Then solid riveting.

I had such an easy time solid riveting the wings, with the specified rivets, the correct die in the tool, and then using the edge of the bench as a guide for the tool, that I decided to use the same system here. Since the flaperons are that much lighter, I made up a couple of wooden supports, which I screwed to the bench, and used straps to hold prevent the flaperon shifting as I worked along the edge.

 

I found I needed a little extra (simple) technique, as the flaperon skins present slightly gapped: at first i tried pinching with thumb and finger next to the tool, but I found i got a better result by placing one finger under the skin trailing edge right next to the tool, and pushing gently up as I squeezed the rivet.

 

As with the wings, there was no need to use anything to hold the edge straight.

 

The last rivet on the outboard flaperon is best left out until the tip is fitted.

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I found the riveting supports also good for holding the flaperon while fitting the plastic tip.

 

I laid a line on the upper and lower sides of the tip with masking tape, as an insertion guide. This allowed me to try multiple fittings as I shaped the rib and the skin.

I next spent a little time shaping the metal of the skin for a near perfect fit round the tip. I found this by far the easiest way to get a good fit with the main wingtips, and here it is very easy as the material is so light.

That done, I then trimmed and tapered the trailing edge of the tip so as to allow a neat closing of the trailing edge of the skin, riveted the tip in place and squeezed the last solid rivet.

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Thank you Eightyknots & Onetrack.

In this, which is my first build, I find a great deal of time is spent working out some of the steps and just how to get them done.

 

There are some excellent Savannah build strands and people on here, so much so that I have a laptop in the workshop for quick reference.

And what I am trying to do here is add my own little bits to that fund of knowledge, not to show my whole build, but to leave what may be helpful to others around the bits that challenged me.

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On 8/18/2016 at 1:01 PM, IBob said:

Next, how NOT to do it:

That's a picture of the RH inner assembly, and you can see I have riveted the inboard end rib...closest to the camera...in place.

 

No part of this rib should be riveted at this stage (although the little bracket that mounts it must be riveted to the spar).

I subsequently found it easiest to cleko the rib until the flaperon was built and skinned, then sort out the necessary riveting sequence for the parts that attach on and around this rib.

Which isn't complicated, I just didn't see it coming...

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Hi IBob

Your internal structures are all white. Primer I assume. Can you please share what you have done in order to protect from corrosion. I notice you have also sprayed all edges where rivets go as well. Please let me know your process there as well - do you first scotchbrite it, clean in any way etc. Look forward to hearing from you.

Barry

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Hi Barry, I know very little about corrosion protection or painting in general, and I'm not much wiser now than when I began my build.

One thing I did discover along the way is that there there are endless different opinions on how to paint aircraft...many of them different, and many of them very strongly held. So much so that eventually I learned to steer clear of the subject, here and elsewhere.

 

How much you do to avoid corrosion etc depends on how much extra work and cost you wish to undertake.

In my case, I believe I made myself a lot of extra work for no great gain in the processes I used. If I were building again, I would only be coating the mating surfaces...anywhere the metal joins...as described in the manual, and I would be using either the black stuff supplied, or zinc chromate, provided I could arrive at an easy and economical way to apply it: the black stuff, being water based, apparently lends itself to rolling on without the roller promptly drying out. Another builder here is just starting his build, and is going to try the zinc chromate, so we'll know shortly how that lends itself to small-batch rolled application.

 

I would not paint along the external rivet lines as I did: it seemed like a good idea at the time, to get some paint under the rivet heads, but it makes for a lot of cleaning back and cleaning up later.

 

I learnt that meths and warm water are good for washing aluminium that has been gathering dirt and grime in the workshop for a year or two, and that it is easy enough to use an air line along the rivets to dry them out afterwards.

And I learnt never again to use white primer under white topcoat: painting the colour on the fuselage was a walk in the park compared with trying to paint white on the flying surfaces. With the colour, suddenly I could see exactly what I was doing and how the paint was going on.

 

 

 

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Thanks again for your feedback IBob. I have a good friend who is an industrial chemist, and works in the metal plating industry. He is a wealth of knowledge with regard to anti corrosion options. What I have learnt from him, is that if you want to carry out corrosion protection on aluminium, there is no easy quick fix. It's the nature of the product. But there are numerous options available, and like you say it's a personal choice at the end of the day. I believe anything is probably better than nothing. Look forward to reading your Notes.

 

Cheers Barry

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Thanks Barry. And we all look forward to reading your notes too!

 

As for the Savannah, I take heart that 6061 aluminium is classed as having excellent corrosion resistance, and while some builders I have spoken with seem to think their aircraft will be around in 50 or 60years time, as many GA aircraft are now, I personally am building with just a small fraction of that in mind.

 

I did a great deal of prep work, and I am happy enough that I did. But I also now think that can be greatly overdone.

 

Cheers

 

Bob

 

 

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Hi Barry

 

For the Mabel rebuild I have opted for alodining all the alu for corrosion protection. This way I still put the black goop on all the mating surfaces but the painting then becomes very easy. just a light undercoat then topcoats

 

We have been doing all our own alodining of the parts but Phil Pluis found a powdercoating place that has huge tanks that they use for "chromating" alu before they powdercoat the items..They call it chromate we call it alodine...same thing essentially. We havent done the the skins yet but have decided 3 of us will get all of our large skins done at this place south of Brisbane..these guys were really carefull with the thin sheets too and its not expensive. I will get all of the new S21 when I get it done by these guys. Its not expensive when you consider the time and money required to do etch priming. Even though it is 6061 alu the inside of mine I did not etch prime and there certainly is a film on the inside after 7 years of having been built this is why I like the alodine. I wasnt aware of it when I built the girlfriend but older and wiser now of course and I think the alodine is the way to go

 

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Thanks Mark. I have investigated a company in Melbourne who does Alodining, but unless you surname is Martin and first name is Lockheed, they're not interested. But I'll investigate others. I haven't got a kit yet, but just doing my due diligence.

 

Cheers Barry

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You'll also need a pool room, a mother-in law's dining room, or somebody else's workshop:

It seems to be part of the ethic in Oz to proceed with the build in an unlikely, variously unsuitable, and usually temporary place.

While over here in NZ, we get wildly excited, buy the kit...then spend the next 6 months to a year erecting a working space before we can take the lid off......)

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Hi Guys,

 

As Mark posted I found a company in Beenliegh that chromated all of my skins at a very reasonable price, around $400. They only charged me at an hourly rate so it depends on how much you have to be chromated as to the cost. For those interested the company is Powdercoating Services Pty Ltd and can be contacted on 07-38047352. Yveyye was the young lady that I spoke with and was very helpfully and the guys in the workshop were great to deal with.

 

Cheers Phil

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