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#2979577 - 03/19/10 11:25 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
JohnnyChemo Offline
Frugalite
Member

Registered: 04/07/06
Posts: 207
Got some more building time in so here's some more pics of the progress.
I finished the elevator, and joined the halves using some 5 minute epoxy. Heavier, but much stronger than CA and the strength is needed in high stress areas. I then slotted the hinge locations in both stab and elevator, and temporarily installed the mylar laminated CA hinges. Some people don't like them, but if you installed correctly, they work great. I also like that it cuts down on the hinge gap, which reduces flutter in the surface.
Here is the completed stabilizer with elevator installed.


I then began working on the fin and rudder. The construction of these is much the same as the construction of the stab, as you can see.



The curved parts of the fin were die cut and laminated, and the rest of the frame was 1/4" x 1/2" stock. The fin ribs were made with 1/4"x1/4" stock, and the cap strips were from 1/4" x 3/32" stock. In addition to providing strength to the rib joints, the cap strips will also serve to provide a ribbed look to the covered fin/stab and give the plane a more vintage look.

Also in this picture is the beginning of the rudder. Online reviews of this kit tend to agree that the rudder is a little undersized, esp. in crosswind situations. Most recommend to build the rudder a little bigger than the kit calls for. The design size of the rudder is 9" x 2 1/4". This is accomplished by taking the same stock as the elevator (which was 1 3/4" wide) and joining some of the 1/2" wide stock used to frame the stab and fin. Instead, I picked up some 1" wide stock and joined it to the the 1 3/4" and built a rudder that is 1/2" wider than plan spec.


Hers is the completed tail feather assembly. If you look back at the stab, there is a slot in the center that the fin fits into quite nicely. This is the first kit I've built which has this feature, and I must say I'm glad. Nothing is more of a pain than trying to be absolutely certain you've joined the tail correctly!


The rudder has a cutout for the dowel joining the elevator halves.


The tail assembly is taken apart (though I'll leave the control surfaces in place for storage) until final assembly. Hinges won't be glued in place until much later.

Next up, the wings!


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#2979581 - 03/19/10 11:50 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
wheelsup_cavu Offline
Lifer

Registered: 12/03/08
Posts: 20404
Loc: Corona, California
cool
Looking good.


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#2981249 - 03/22/10 10:43 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
JohnnyChemo Offline
Frugalite
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Registered: 04/07/06
Posts: 207
Looking at the plan, it seems like a made an error in the fin. The part circled below is actually supposed to be part of the rudder.


It's not an issue that will cause any problems in flight, but I kinda liked the way it is supposed to look. So I broke out my trusty razor saw, chopped it off, and attached it to the rudder. I had to add a strip of balsa to fill it in a bit, but with wood filler and covering later on, you'll never know it was there. So it will look like this when it moves.


On to the wing.
The wing is built in two halves and then joined together. I'm about halfway through building the right half, so there it will take some time for another update as I will then go through and build the left half. After that, they get joined together. But I'm getting ahead of myself...

Step one is to lock down the main spar to the plan. I do that with T-pins as you can see.
The instructions are also in view. I have to say they have been very easy to read and straightfoward to follow.


The spar is basswood, a harder, denser wood. Up to now I've been working with balsa (albeit a couple different grades). The harder wood is used in higher stress areas, and you can imagine the stress the main spar of the wing undergoes.

Next we fit the ribs (back to balsa for these) to the spar. Notice the last rib is longer than the others as it is positioned outside of the ailerons.


Once they are glued down, I glue in the second main spar on the top of the ribs as well as the secondary leading edge spar (balsa this time) toward the front of the ribs. You can also see what will become the leading and trailing edges of the wing in the picture.



Here the leading and trailing edges have been glued in place, and the wing is beginning to really take shape.



Now I've added thin balsa sheeting to the leading and trailing edge (as well as a good dose of CA on my fingers!) The materials overhanging the rib will be trimmed away later.




An edge on view of the wing from the (as yet unfinished) wingtip. Looking at the shape of the ribs, you will notice they are flat at the bottom rather than curved - actually there is a slight curve to them. This is a semi-symmetrical non-tapered wing - as opposed to flat bottomed or symmetrical. A flat bottom wing is used on training models. It is very gentle and has great glide characteristics. It will slow down nicely for landing and recover from stalls easily. It won't do much by way of aerobatics though. The fully symmetrical wing is the opposite - lands (and flies) faster, will handle all maneuvers, including inverted flight, nicely. The semi-symmetrical is, as you probably have guessed, somewhere in the middle. It isn't as stable and gentle as a flat bottom, nor as wild and sporty as a symmetrical. It will give me more 'relaxing' flights, and I'll use the other plane I showed earlier in the thread (which has fully symmetrical, tapered wings) when I want to cut loose a little.

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#2985639 - 03/29/10 10:07 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
JohnnyChemo Offline
Frugalite
Member

Registered: 04/07/06
Posts: 207
It's been a busy week, but I managed to get a little more work done on the right wing.

Here you can see the shear webs attached to the main spars and in between the center section of ribs. The grain orientation is important, and will help the spars to share the load as the wing flexes in flight.


Here is the mostly completed wing half. Biggest difference between this picture and previous ones is the center sheeting on the left (root) side of the wing and the shear webs.


As I mentioned before, the wing is built in halves and the halves are then joined. The Trailing Edge Brace, Leading Edge Brace, and Dihedral Braces will help join the wing at the proper angle. Here you can see them installed in a bottom view of the wing. They are attached with a 30 minute epoxy. Up to now, everything has been glued in place with CA (cyanoacrylate glue aka super glue). It holds well, but for the highest stress areas, the stronger yet heavier epoxy is preferred. When I join the wing halves, I'll use epoxy with a piece of fibreglass tape laid in for maximum strength.


I had to cut slots in the end rib to fit the braces in, and in the process mangled the rib. You can see where the rib was damaged as well as the pieces on the bench in front of the wing.


A little CA and it's as good as new.


A little extra balsa where the rib broke won't hurt either!


Next step is to build the left wing half. Since it's the same, as the right, I won't bother documenting it, so my next update may be a couple of weeks away!

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#2986436 - 03/30/10 10:32 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
wheelsup_cavu Offline
Lifer

Registered: 12/03/08
Posts: 20404
Loc: Corona, California
Looking good. smile


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#2995675 - 04/15/10 06:54 PM Re: Build thread: Elder 40 [Re: wheelsup_cavu]
jt189 Offline
Junior Member

Registered: 04/15/10
Posts: 6
Loc: Earth
Time and patience you are doing such great work. enjoy watching the rc planes fly and the planes some of the modelers make ww11 and the jet age.

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#2999080 - 04/21/10 03:51 PM Re: Build thread: Elder 40 [Re: jt189]
JohnnyChemo Offline
Frugalite
Member

Registered: 04/07/06
Posts: 207
The wing is finally finished, here's some highlights:

Since I left off, I've completed the left wing half. Once that was done, it was time to finish the bottom of the right wing. The leading and trailing edge panels as well as the center panel and capstrips have been added in this pic.


Next, we add the control mechanism for the right aileron. The control arm is inserted into the shaped balsa block with is then glued to the trailing edge at the wing root. The threaded arm has a control arm attached to it which will then attach to the aileron servo. The rod parallel to the trailing edge with the 90 degree angle in it will attach directly into the aileron.


The two wing halves are joined using 30 minute epoxy for maximum strength. After joining the wing halves, I'll reinforce the joint with fiberglass tape epoxied to the joint. This will increase the strength of the wing joint exponentially.


Yuck. The joint between the wings isn't as tight as I would have liked. I'm not too worried though, as the epoxy/fiberglass tape will provide all the strength we need.


Here you can see the fiberglass tape joint on the underside of the wing. The opening on the wing is where the aileron servo will sit.


A closeup of the wingtip. This is an unusual wingtip. All the other planes I've built have had wingtips made out of balsa blocks which you shave and sand into shape. All I can figure is that the structure will add to the vintage look once covered.


Here is the completed wing, top view. You can see the ailerons (not glued in place, just attached by the hinges) as well as fiberglass tape joint and reinforcing blocks for the wing bolts.

At this point, the wing is pretty much done. Some work will be done as some point during the fuselage construction to place the wing bolt holes and the dowels in the front to secure the wing for flight.



Next step is the build the fuselage. Here is the engine I've selected for this model. It is an O.S. 46AX nitromethane fueled 2 stroke engine.

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#3010462 - 05/11/10 10:09 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
JohnnyChemo Offline
Frugalite
Member

Registered: 04/07/06
Posts: 207
Ok, onto the fuse.
Here we see the right side of the fuselage and the parts for the left.


Putting the parts together, I used epoxy rather than CA due to the bass wood longerons (CA doesn't seem to bond bass as well as balsa)


Now the formers for the fuse are inserted into the right side.


Before the fuse sides are joined, the firewall is put in place. Here is the view from the backside. The blind nuts will hold the engine mount in place.


The right side of the fuse with formers and firewall in place.


The fuse halves have been joined, and now the tail section longerons are joined with 1/4" bass to give the open structure look to the tail. These are epoxied in place. The epoxy takes about an hour to get to full bond strength, so its slow going.


Still lots to do on the fuse, and of course it's getting busy at work and around the house, so it's gonna slow things down a bit more.

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#3016326 - 05/21/10 11:01 PM Re: Build thread: Elder 40 [Re: JohnnyChemo]
wheelsup_cavu Offline
Lifer

Registered: 12/03/08
Posts: 20404
Loc: Corona, California
cool
You're getting there.


Wheels
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Wheelsup_cavu

Mission4Today | Get RoF Templates @ Combat-Asylum
Planes of Fame Air Museum | March Field Air Museum | Palm Springs Air Museum

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#3016352 - 05/21/10 11:57 PM Re: Build thread: Elder 40 [Re: wheelsup_cavu]
JohnnyChemo Offline
Frugalite
Member

Registered: 04/07/06
Posts: 207
Slowly but surely!

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