Savannah S Build Notes - Rear Fuselage

[IBob]

The rear fuselage goes together well and easily, with a sort of riveting marathon at the end.

 

However, be sure to work out the luggage area especially if you have the extended luggage, before fitting the skins.

 

The extended luggage kit also contains patches for the parachute hatches in the top skin (assuming you are not fitting the parachute). As I discovered after making my own...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[IBob]

I bevelled one edge of the (black plastic) control cable bearers so that they fit flush into the curved corners of the frames.

 

 

[IBob]

And right at the end of this lot, I should have fitted the extended baggage area...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[IBob]

I did fit grommets and pullthrough for the elevator trim wiring...

 

Using the 50X50 battens wrapped in bubble wrap to give clearance for the clekos underneath.

 

 

 

 

 

 

 

 

 

 

[IBob]

And the curved corners to the fuselage were surprisingly easy to fit, too. They just sort of zip from front to rear.

 

 

 

 

 

 

 

[IBob]

As were the little front corner skins.

 

 

 

 

 

[IBob]

With clekos in every 3rd longeron hole, and a few elsewhere to hold things flush, I used all my copper clekos and a good number of the black.

 

Then the rivet marathon....and voila!

 

 

 

 

 

 

 

[IBob]

Then on to fitting the other rear fuselage bits and pieces...and retrofitting the extended baggage, which is simple enough, but I really, really should have assembled and clekoed the whole lot before any riveting.

 

 

 

 

 

 

 

 

 

 

 

[rmorton]

Then on to fitting the other rear fuselage bits and pieces...and retrofitting the extended baggage, which is simple enough, but I really, really should have assembled and clekoed the whole lot before any riveting.

Thanks IBOB, that is a fantastic resources for when I finally get started. what primer did you use ? I am doing the rudder and have a Stewarts systems water based one for now, but I think that a two pack epoxy will be better for the fuselage. I am just a bit worried about mixing them. Thanks for the photos and notes!

 

 

[rmorton]

And right at the end of this lot, I should have fitted the extended baggage area...

More questions, in photo 841 showing the lower rudder bracket, what difference / why does the middle rivet need to be a flat head? Did you counter sink the hole?

 

 

[IBob]

Hi RMorton and thanks. As you will already have noticed, there are many and varied views on paint systems, and I certainly don't claim any expertise. I was, however, urged by a LAME to prime the interior, NZ being long narrow islands surrounded by thousands of miles of salt water.

 

I am using Wattyl Super Etch Primer. There is nothing flash about this, and it is certainly not classed as an aviation product. As you can see, I am using the white, but I would not do that again: the white seems to be a quite different product than the standard grey and with much less 'body' so I have been using a lot of it, with very little thinning, to get adequate cover.

 

I am learning to spray on the job, and will do my own finishing paint (I hope), with some expert input. To improve my chances, I will set up wing and fuse etc so I can rotate them: I am big on using jigs to make life easier.

 

As noted elsewhere, my aim and wish is to get into the air: while I am wanting a tidy job, I am not aiming for a concourse finish...

 

 

[IBob]

More questions, in photo 841 showing the lower rudder bracket, what difference / why does the middle rivet need to be a flat head? Did you counter sink the hole?

My manual shows the centre rivets on the brackets on the rudder as flat, and yes they are countersunk. That will be to provide clearance for the pivot.

Photo 841 shows the brackets on the fuse, and there is no need of flat rivets there, as the pivot hole is further out.

 

 

[rmorton]

My manual shows the centre rivets on the brackets on the rudder as flat, and yes they are countersunk. That will be to provide clearance for the pivot.Photo 841 shows the brackets on the fuse, and there is no need of flat rivets there, as the pivot hole is further out.

Phew thats a relief, having tried to shove a rivet in it looked anything but flat so decided to countersink just enough. I haven't got as far as you so couldn't tell if the fuselage ones needed them.

Todays job for me is to prat about spray painting and see how I get on. I did some last night with a model makers airbrush on the smaller parts which worked ok but the paint was good thick and has a rough finish. The real worry is the time I spend preparing. cleaning off the stencilling with acetone, cleaning off the the grease and then surface treatment of whichever method takes my fancy. Cant wait to get riveting !

 

 

[Kyle Communications]

Hi Bob

 

I am about to make my longerons to replace them in Mabel as I hope to be picking up my rear frames and some other parts from Reg Brost next weekend. Can you tell me if they are bent at 90 deg please?. The ones in this aircraft seem to be about 85 or so. I can get our CNC V folder to do any angle of bend so I just need to confirm that all of yours were bent at 90 deg out of the box please

 

Mark

 

 

[IBob]

Hi BobI am about to make my longerons to replace them in Mabel as I hope to be picking up my rear frames and some other parts from Reg Brost next weekend. Can you tell me if they are bent at 90 deg please?. The ones in this aircraft seem to be about 85 or so. I can get our CNC V folder to do any angle of bend so I just need to confirm that all of yours were bent at 90 deg out of the box please

 

Mark

My recollection is 90 deg.

Will check what I can get to and reply in the morning, Mark.

 

 

[Kyle Communications]

no probs thanks Bob

 

Wont be doing them until next week.

 

 

[MajorTom]

The white etch primer might be a little more in weight, but it surely lookes highly professionel.

 

I'm intending to use grey etch primer, after I finally was able to find an affordable source in germany.

 

 

[rmorton]

The white etch primer might be a little more in weight, but it surely lookes highly professionel.I'm intending to use grey etch primer, after I finally was able to find an affordable source in germany.

Any news on delivery? Grey is good as an undercoat as you can see when you have covered it properly with the white

 

 

[IBob]

Hi BobI am about to make my longerons to replace them in Mabel as I hope to be picking up my rear frames and some other parts from Reg Brost next weekend. Can you tell me if they are bent at 90 deg please?. The ones in this aircraft seem to be about 85 or so. I can get our CNC V folder to do any angle of bend so I just need to confirm that all of yours were bent at 90 deg out of the box please

 

Mark

Hi Mark,

my longerons all measure 90 deg, with some very small local variations on that (as you would expect, and more noticeable down the tail end) now they are built in.

 

The internal radius of the bend, measured with the shank of a drill is 2.8 to 3.0mm.

 

 

 

 

 

 

 

[IBob]

The white etch primer might be a little more in weight, but it surely lookes highly professionel.I'm intending to use grey etch primer, after I finally was able to find an affordable source in germany.

As previously noted, this is my first build and I have no practical experience with paint or painting for aircraft.

While I am reasonably happy with my paint choice so far, I am certainly NOT recommending it to anyone else at this point: It remains to be seen how the finishing goes, and after that how the paint job stands up to a few years use.

 

I will certainly post any problems or difficulties I strike along the way. That way, hopefully, we all learn.

 

 

[Kyle Communications]

Thanks Bob for doing those measurements. I can get them all made next week :)

 

 

[MajorTom]

As previously noted, this is my first build and I have no practical experience with paint or painting for aircraft.While I am reasonably happy with my paint choice so far, I am certainly NOT recommending it to anyone else at this point: It remains to be seen how the finishing goes, and after that how the paint job stands up to a few years use.

Some time ago I found this video about priming mating surfaces. Priming Mating Surfaces

 

I esp. like the heatgun trick, but don't know if this is a healthy choice.

 

 

[IBob]

Some time ago I found this video about priming mating surfaces. Priming Mating SurfacesI esp. like the heatgun trick, but don't know if this is a healthy choice.

I think we can agree that the object of priming mating surfaces is to minimise corrosion. And to that end, we are wanting the most effective coating.

It seems odd to me that the video:

 

1. Makes no mention of cleaning/degreasing the metal before painting:

 

Quite simply, the stuff won't stick properly unless the metal is clean.

 

2. Suggests rapid drying of the primer with a heat gun:

 

a) These are etch primers, which implies that the primer is etching the surface of the metal to improve adhesion. Does rapid heat drying allow proper etching?

 

b) Hardening of coatings can be more complicated than just 'drying them out'. That is, the coating may be undergoing chemical/structural changes. Has the maker of this video checked with the manufacturers of the various products he lists, to ensure that rapid heat drying does not compromise the coating?

 

3. Suggests the parts can be assembled almost immediately:

 

You may be able to get away with this if there is no movement of the parts during assembly. But since the coating will still be relatively soft and uncured, any movement will almost certainly damage the coating. And quite a lot of assembly involves wriggling or sliding things to fit.

 

 

[rmorton]

I think we can agree that the object of priming mating surfaces is to minimise corrosion. And to that end, we are wanting the most effective coating.It seems odd to me that the video:

1. Makes no mention of cleaning/degreasing the metal before painting:

 

Quite simply, the stuff won't stick properly unless the metal is clean.

 

2. Suggests rapid drying of the primer with a heat gun:

 

a) These are etch primers, which implies that the primer is etching the surface of the metal to improve adhesion. Does rapid heat drying allow proper etching?

 

b) Hardening of coatings can be more complicated than just 'drying them out'. That is, the coating may be undergoing chemical/structural changes. Has the maker of this video checked with the manufacturers of the various products he lists, to ensure that rapid heat drying does not compromise the coating?

 

3. Suggests the parts can be assembled almost immediately:

 

You may be able to get away with this if there is no movement of the parts during assembly. But since the coating will still be relatively soft and uncured, any movement will almost certainly damage the coating. And quite a lot of assembly involves wriggling or sliding things to fit.

It is a strange approach as far as the cleaning was concerned. I wonder if the idea of heating the paint is to make a touch dry film on both sides so that you can handle them for assembly and then when assembled the two partly dry surfaces are still able to fuse together?