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Aeronca Sedan

Mercury Kit

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Erfolg28/06/2020 14:00:08
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I am finding a major problem with this particular model, which I am building from the proverbial off cuts box, is keeping the bench anything approaching tidy.

Habitually I put all the tools back to predetermined homes, the majority on my IKEA Billy book cases. Except it seems when I make some slight progress, where I find piles of tools of varies types. Saws, French Curves, set squares, sanding blocks and piles of bits of wood I have been going through, from the offcuts box.

My other issue, is that in some instances I have deviated from my drawing, and more work is then required to get back to how it should be. Then again, the various links that have been provided have shown that some of my structure is pretty beefy compared to full size. Although I am very much a it must fly well, but should bare some resemblance to scale when viewed at twenty feet whilst squinting, type of modeller, I am beset with internal, self inflicted issues as to what extent to compromise. The other issue is that my detail design follows the practices of PM and a certain Gordon Whithead "Scale Aircraft, for everyday flying", where I seek reassurance that what I have drawn is practical, robust, sympathic to the full size. At the back of my mind, is a issue, where I was less than happy with some one elses design, I let it go, latter came to regret it. Design can be both fun and a battle with your own internal demons, Hmmm, time for a whisky, whilst i contemplate what PM and Gordon would do.

Yes kits are much easier, ARTF, require no thought and almost no skill. Perhaps that is the way of the future.

Erfolg02/07/2020 14:59:33
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As is usual, not everything goes to plan. Indeed much of what could have been planned ,has not.

I had written that I intended to start on the wing. As I laid out my plan I realised that I needed to have the central part of the wing as a starting point. On the full size this part is part of the cabin/fuz. Indeed the Mercury approach was follow pretty much full size practice, with, plug in, wings that sprung out on an arrival.

I have dithered on this area, for some time. I had decided that I needed a hatch in the cabin roof to gain access. This would allow for the mounting of servos, Rx etc. The mercury approach was a door on the right hand side (from memory), for this purpose. I was and am not enthusiastic to this approach, as a significant re-enforcement would be required to replace the lost integrity caused by the opening.

I was not keen on a hatch, as this required plug in dowels, such as used on model gliders.

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You may recall that I still have a selection of joiners. From high strength aluminium, brass box and steel strip, a selection of brass tubing and piano wire inserts, and some polyester spar capping (made from glass string).

I have a few brass box type arrangements that were salvaged from a 144" fling wing that I built, with the gliding characteristics of a "lead Butterfly". Which unsurprisingly was consigned to my bin of failed projects.

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I weighed the bits that immediatly came to hand, which came out at 50gram each. Without to much imagination, I realised that I was looking at +100g assembly. I have never been to impressed with the brass tube and piano wire arrangement, other than a glider on tow, could benefit from the piano wire bending at the root body interface, if over stressed, rather than some part of the wing failing. There were other permeations, which benefited from the parallel axis theorem, if bolted up solidly. All were pretty heavy, in practice, although there would not be any failure at the root.

I spent a lot of time planning to make a solid epoxy, glass tow/string joiner often seen on modern high spec gliders, something approx 12-15mm square cross section at about 300 long. Then the doubts set in.

On balance I thought, you know, this is a light, civil aircraft, at best stressed for simple aerobatics, It does not need the strength of a tow line glider or a aerobatic model, that will do a Lomcovac type manoeuvre.

On that basis I have decided to run the spars into the cabin to area, and just rely on ply bracing and shear webs on the rest of the wing. I will put enough (I hope) material in the cabin to area to resist any crushing tendencies. This will now be a one piece wing. At 58" span in this era not big.

So what has taken me so long to do apparently nothing? Well, I am slow, plus most of the area is ply, needing a lot of sanding. Ah, yes, that indecision.

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Just about ready to start what I intended doing about a week back.

I am still on track, relying mostly on my bits boxes.

Edited By Erfolg on 02/07/2020 15:03:18

Erfolg16/07/2020 17:33:40
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Right, then. I have started on the wing, still quite a bit to do.

I have made a number of errors, which I have fudged. Plus some deviation from the drawing I have done.

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At least it fits, quite well, it seems.

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I have struggled to keep the work surfaces tidy and debris free. That is my next job before moving on, to the servo hatches, a few bits for the hinges to fasten into, plus the wing strut re-enforcement.

Then my attention will turn to the UC. and finishing the motor cowling.

Erfolg29/07/2020 11:56:13
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A little more progress has been made. That is after a number of cock ups, which I have struggled to bodge. Being a philistine, that is what I have done. The craftsman would have undertaken a far more fundemental rebuild of the affected areas.

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Erfolg31/07/2020 11:18:00
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This morning I thought that at last I had the wing finished to at least 90%. Returning indoors with the wing, I felt then saw another issue, which i started the process of rectifying. Then I found yet another, which needs dealing with. Will I ever finish the wing.

I was threatening to turn my attention to the cowl. I had tacked it on, for the shaping process. It is such a long time back, I cannot remember with any certainty of where. I then vaguely remembered why there is an apparent slot in the top of the cowl.

When the weather turns for the worst I will return to the cowl, in the mean time I am going out flying (this afternoon), I have watered the flowers this morning, so that is done.

I will be looking for constructive advice in how to secure the tail unit, as even with the faired plate (non scale) I have introduced, this area is pretty weak. I have been thinking along the lines of CF bracing, glued in position, to mimic wire bracing wires. The issue is ther is not a hobby shop within 70 mile radius as far as I am aware. To send away for a couple of pieces would make the PO richer, for the price of a few quid of CF

PatMc31/07/2020 20:09:11
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Posted by Erfolg on 31/07/2020 11:18:00:

I have been thinking along the lines of CF bracing, glued in position, to mimic wire bracing wires. The issue is ther is not a hobby shop within 70 mile radius as far as I am aware. To send away for a couple of pieces would make the PO richer, for the price of a few quid of CF

Any kite specialist shops near you ?

Erfolg31/07/2020 20:22:47
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Not that I aware off. I will Goggle just in case.

We normally do have kite festival though, once a year, probably in August or September. I guess that will be cancelled along with the Lytham Festival (we have had Tom Jones, Kylie etc ).

Unfortunately we are at the end of the road to no where, other than for the several hundred people on the Green, in the local pub and on the beach today. Worrying, as people from many areas of the NW have been told not to make journeys that are not essential. We could become yet another part of the hot spots.

Bob Cotsford31/07/2020 22:35:04
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Anglers seem to use some model friendly materials Erf, maybe some kevlar 'wires' for bracing the tail. Or actual wires using nylon covered stainless fishing trace as I've used on a few models?

Richard Clark 201/08/2020 05:01:03
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Posted by Bob Cotsford on 31/07/2020 22:35:04:

Anglers seem to use some model friendly materials Erf, maybe some kevlar 'wires' for bracing the tail. Or actual wires using nylon covered stainless fishing trace as I've used on a few models?

Yes. The tail on the Mercury Aeronca is very wobbly. It was designed as a free flight model and had a 'knock off' tail. In addition the real Aeronca and thus the model has a very narrow tail seating. On the real one the tailplane is wire braced to near the top of the fin and the bottom of the fuselage.

I glued the tailplane on and replicated the bracing with Kevlar fishing line and it's fine. Though the much cheaper 'Dacron' would be just as good...

Peter Miller01/08/2020 09:07:41
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I used 20lb nylon covered fishing trace which comes complete with crimps for the rigging on my Chaos.

**LINK**

.

Erfolg01/08/2020 15:02:11
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I am trying to avoid flexible wire, as it needs a degree of tensioning to work well.

I do have some Stainless steel Nylon Covered fishing wire, left over from my glider days (closed loop sytem). Never really been a fan, although it does work.

I am thinking more 1.5mm or so CF that I can Cyno. The issue is I do not know a source anywhere near here. It seems that the only solution is to send away for some. In the distant past I bought CF from Robotbirds (for indoor Model) then, if not now the P&P was acceptable. I was even able to use the tube (that the materials came in) for installing 480 in-runners,

Perhaps I should emphasis, I want a model that I can fly in most circumstances and throw into the car. Rather than all aspects of the full size being adhered to. To my eyes the tailplane assembly is rather fragile.

Keep the ideas coming, as I will start Googling today for local fishing tackle shops. Living by the sea, you would think you would see many rod fishermen. I see non. Although the cocklers are back, on the Ribble estuary. I guess it is the sea goes out for miles, then rushes back. All the local piers are high and dry at low tide. I guess that could explain a lot.

Bob Cotsford01/08/2020 15:50:03
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How long are the rods? Maybe something off ebay?

Erfolg01/08/2020 16:55:36
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Sorry Richard, your post appeared in my in tray, out of order, for some reason. I agree the back does appear to be wobbly.

Bob, there appears to be 4 of them. In one photo one of the wires appears to have been replaced with a strut from the leading edge of the tail plane to the bottom of the fuz, all the other photos on Google appear to have wires. What makes certainty, less than certain, is that the vast majority of the photos are from the front, or the back end is slightly out of focus.

The length of the wires appears to be circa +300mm.

Richard Clark 201/08/2020 17:39:09
422 forum posts
Posted by Erfolg on 01/08/2020 16:55:36:

Sorry Richard, your post appeared in my in tray, out of order, for some reason. I agree the back does appear to be wobbly.

Bob, there appears to be 4 of them. In one photo one of the wires appears to have been replaced with a strut from the leading edge of the tail plane to the bottom of the fuz, all the other photos on Google appear to have wires. What makes certainty, less than certain, is that the vast majority of the photos are from the front, or the back end is slightly out of focus.

The length of the wires appears to be circa +300mm.

Erfolg,

Wire would be finer but Kevlar or Dacron is easier . But don't let your modelling knife get anywhere near Kevlar or Dacron when it's done .

On each side in the real one there are two wires from near the top of the fin to the taillplane and there are two from the bottom of the fusalage. If lightly tensioned (Kevlar and Dacron don't really stretch) their flexibility is fine as whichever way ther tailplanr tries to bend thry will alwayd be two cable ach side stopping it.

Peter Miller01/08/2020 18:37:33
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Well when I fitted the wires tothe Chaos tail it was easy. I threaded the wire thor a 8ba solder tag and locked it by squeezing the crimp with pliers. Then pulledit tight and di the same at the other. end. I ended up with 8 nice tight wires.

They will not come loose.

Just how were you planning on securing your carbon rods because I can imagine one good knock will pull them loose from balsa.

Richard Clark 201/08/2020 21:05:30
422 forum posts

Erfolg,

Further.

I put 1/4 square hard balsa blocks in the tailplane attached to convenient ribs and filed/sanded to match the rib edges and similarly a slightly larger block with two adjacent holes on a cross piece of the fin. Then I drilled small holes though the blocks and similar (2) holes in the fuselage lower longerons All the longerons gather together at the tail so are strong and a pair of small holes each side  won't matter.

Then I covered the plane, not forgetting to poke a length of 20 or 22g wire though the covering to act as a marker before I covered the other sides. Then you can poke a hole in that side too.

When fully covered I passed a long length of Kevlar line though each set of holes, keeping each section slightly tensioned as I went and securing the line at each location with a tiny drop of cyano before I moved to the next., If you harden a couple of inches of the line with cyano  it's easy to push though the holes, even the lower fuselage ones, where the two ends pass each other and are later cut off, lightly pulling on the 'tag ends' of both at the same time when glueing. (Leave this 'double' glueing till last.)

 

It'd easy and look neat (provided  you haven't splashed  the cyano around). Should you break one at some later time you can carefully drill out the blocks and replace it, but ir's unlikely to happen as the line is very strong..

 

Edited By Richard Clark 2 on 01/08/2020 21:18:33

PatMc01/08/2020 21:34:22
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Posted by Erfolg on 01/08/2020 16:55:36:

Sorry Richard, your post appeared in my in tray, out of order, for some reason. I agree the back does appear to be wobbly.

Bob, there appears to be 4 of them. In one photo one of the wires appears to have been replaced with a strut from the leading edge of the tail plane to the bottom of the fuz, all the other photos on Google appear to have wires. What makes certainty, less than certain, is that the vast majority of the photos are from the front, or the back end is slightly out of focus.

The length of the wires appears to be circa +300mm.

There are several good photos of the tailplane bracing wires in the site that's been linked on here already. For example here & here. Probably more if you look through the site's "Sedan gallery".

Richard Clark 202/08/2020 06:31:32
422 forum posts
Posted by PatMc on 01/08/2020 21:34:22:
Posted by Erfolg on 01/08/2020 16:55:36:

Sorry Richard, your post appeared in my in tray, out of order, for some reason. I agree the back does appear to be wobbly.

Bob, there appears to be 4 of them. In one photo one of the wires appears to have been replaced with a strut from the leading edge of the tail plane to the bottom of the fuz, all the other photos on Google appear to have wires. What makes certainty, less than certain, is that the vast majority of the photos are from the front, or the back end is slightly out of focus.

The length of the wires appears to be circa +300mm.

There are several good photos of the tailplane bracing wires in the site that's been linked on here already. For example here & here. Probably more if you look through the site's "Sedan gallery".

 

The colour and registration of mine is that one.

With one detail I think is important - the line of the curve on the colour panel behind the cabin windows. That panel was part of the standard factory colour scheme for all of them except some early ones, and tends to make the plane instantly recognisable as an Aeronca Sedan.

But over the years most, possibly all, have been repainted and many don't get the line of the curve right and as a result some look rather ugly. The linked plane does get it right.

Just a comment on 'vintage models'. Although the Mercury kit came out about 1953 (and incidentally,   depicts  the early colour scheme) I don't think of it as 'vintage' model and our construction methods (except for ARTFs) haven't changed significantly since. So I think of it as a scale model of a (marginally)  'vintage' plane  rather than  a vintage 'model' and personally wouldn't enter  it in  'vintage' meet. no more  than I would a modern   kit or ARTF of a Sopwith Camel  

Edited By Richard Clark 2 on 02/08/2020 06:57:08

Erfolg02/08/2020 11:10:11
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You are both correct (Patmac & Richard).

In a way i had forgotten about these links, although having read them a number of times.

Even when being re-reminded, I had not spotted the specific pictures linked by yourselves. In a way it is the combined knowledge and brains that resolves and clarifies many issues for the builder.

I have made a number of errors, due to not knowing how the originals were built. Much of the sheeting i have on the outer surfaces at the front would have been omitted. Particularly in that I have sheeting on the box area at the front, to take and distribute the landing forces, plus something to get my servo plate & beams attached to. I assumed that the outer cabin area had been sheaved in plywood, as all the various plans and kits had sheeted this area.

Perhaps another not yet completed is the cowl. There are so many variations, I expect due to replacement at various times, probably during a motor replacement. My own is based on that the original is bent sheet material. Yet the nose area seems to be well rounded on some aircraft and on others,a minimum radius. I had thought that the original would be a mim radius. This based on my month long experience, almost 60 years ago , where I found that making a square to round item required a lot of bashing, a scar on my hand from the metal bit on a hide mallet. Although probably the biggest error in this area, is that I have just the one aperture for the oil cooler and carburetor, where the vast majority of cowls have this area split.

I am now working on the cowl.

My mind is turning to the detail of the wing struts, and fixating on increasing the robustness of the tail group. Where I am now thinking will require a lot more material, than a quick glance suggests. I am also thinking of some CF rods from the Fuz, through the tailplane and into the fin, as this general area seems rather weak, when subjected to me, storage and my flying.

Considering these issues, the cost of P&P could be minimal to the cost of the CF rod.

I know that what I am suggesting is not as visually true to scale as some other solutions. I tend to see it as PM pragmatism. Just like enlarging a tail plane area, to obtain better RC handling, although on this model that is not required.

David Davis02/08/2020 11:13:15
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Posted by Richard Clark 2 on 02/08/2020 06:31:32:

.... Just a comment on 'vintage models'. Although the Mercury kit came out about 1953 (and incidentally, depicts the early colour scheme) I don't think of it as 'vintage' model and our construction methods (except for ARTFs) haven't changed significantly since. So I think of it as a scale model of a (marginally) 'vintage' plane rather than a vintage 'model' and personally wouldn't enter it in 'vintage' meet. no more than I would a modern kit or ARTF of a Sopwith Camel

Edited By Richard Clark 2 on 02/08/2020 06:57:08

Oh I don't know Richard, I used to go to the Cocklebarrow Vintage October Festival regularly and I've seen SE5s, Flying Fleas and other models which could well have been own designs in amongst all of the usual vintage sports models. I'm sure they'd welcome an Aeronca Sedan.

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