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Saab 37 Viggen - Custom Wings 1:9 scale turbine

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Saab 37 Viggen - Custom Wings 1:9 scale turbine

Old 02-21-2022, 09:34 PM
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rustyives
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Default Saab 37 Viggen - Custom Wings 1:9 scale turbine

I started this short kit from Custom Wings a year or so ago, and couldn't find anyone else on-line making one, so thought I'd start this thread with the build in it.
Old 02-22-2022, 01:09 AM
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Default Australian vendor - HolkRC

https://www.holkrc.com.au/

This is the vendor I purchased the short kit from. As its intended for a turbine, I didn't buy the EDF intake ducts and saved a few dollars. It came with the laser cut parts and the canopy. No plans or documentation is supplied.
Old 02-22-2022, 01:11 AM
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Default


Kit as supplied, plus a sheet pack of 2.5mm balsa I purchased at the same time.
Old 02-22-2022, 01:15 AM
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Default 3D jigsaw puzzle


Somehow it self assembles into this....
Old 02-22-2022, 01:22 AM
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Default So its a two piece...


Custom Wings design concept is a two piece, split down the middle. Makes a lot of sense for a low aspect ratio jet and saves on jigs.

Engine cover on the bottom, intended for an EDF fitout.




Wings detach in-line with the forward canards. Note the undercarriage in inboard so assembly at the field should be easy
Old 02-22-2022, 01:27 AM
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Default Step 1 - Organise those parts

As this kit is a mirror image, there are two of every part. So in order to check if I have all the parts, and to put some order in the 3D jigsaw, I strongly recommend spending the time to sort it out into matching parts.

Play match the parts....
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Old 02-22-2022, 01:30 AM
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Default Find those missing parts

I did end up with a few missing parts following my organisation. But Kevin from HolkRC was really helpful in cutting out some fresh ones (after he searched his workshop floor!). The only 'pair' of parts I was missing was Frame 1, but they are really small so I'm not surprised they vanished.
Old 02-22-2022, 01:38 AM
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Default So, those plans...

OK, the 3D jigsaw is quite the challenge, but Kevin from HolkRC sources some CAD images from Custom Wings to help explain how all the various shapes go together. They all interlock so its just match the same and glue it in. I've included a bunch of the images provided to help other builders.


















Old 02-22-2022, 01:40 AM
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Default The old CoG question....


As provided by Custom Wings, the CoG is quite far forward, so a consideration when building and doing the install of components
Old 02-22-2022, 01:59 AM
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Default Let the gluing commence....

Due to its mirror split design, building on any flat surface is easy. It also helps keep the plane straight laterally.

However, as there are no reference plans, itís difficult to determine if the plane is being built like a banana (i.e. nose and tail sagging). ** Recommendation to Custom Wings to provide a plan to lay the build on so that I have a reference to build from. **

I recommend laying down a piece of tracing or semi-transparent paper and making vertical lines where the frames sit. It was designed in metric, and found most frames are 80mm apart. Then trace the outline on the paper and flip it over to do the other side, and like magic you have a reference which should match the first side.


1:48 plastic kit for reference. Doesn't really help at this stage though.
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Old 02-22-2022, 02:03 AM
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Default Wing Spars

I recommend have the carbon spars handy when building the wings and installing them during the build. I was a bit impatient and found that the holes for the Carbon spars were too small, so had to remediate later.

I purchased a 1m length of 14mm Carbon wing tube (2mm thick) with a 16mm outer sleeve. The length was fine. Donít put it all the way through or it will get in the way of the thrust tube.

Lucky I had the wing tubes before assembly of the second half, it was much easier to enlarge the holes in the frames while the kit was still in pieces.
Old 02-22-2022, 02:21 AM
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Default Quick fit of the turbine

I have a Kingtech K-85 going into a sports jet so thought Iíd give it a quick fit for size. It fits in fine, the only question is how far forward to put it, noting the fuel tank wants to be at the CoG. The tank in the picture is just a Dubro 3000cc for scale, probably not the ideal shape.

My thought is probably fitting a 100N in the future, and size it for that. Flight weight is alleged to be 7-10kg according to Custom Wings and they recommend a 80 Ė 120N turbine. However, the rate of development by the time I get to buy it, it will probably be the same size as my 85N unit!



Old 02-22-2022, 02:23 AM
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Default First half finished


Old 02-22-2022, 02:26 AM
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Default Second half on the build


Itís much easier when there is a handy reference.
Old 02-22-2022, 02:35 AM
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Default I have a whole plane now

Given space constraints in my workshop, the only sensible thing to do was to hang it from the roof.

Note this is six months of work up to here for me. I donít build very fast and like to jump from project to project doing little bits on each. However I have sourced the undercarriage now, but that is a story to tell on another night.

Old 02-22-2022, 03:37 AM
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Great work. I emailed the maker about buying a kit sometime ago and they told me they were waiting for feedback, maybe you are that person. Btw Rc crafters makes a main gear set for the Viggen.
Old 02-22-2022, 06:23 AM
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That looks like a cool project! Will have to check them out... Good luck with your build!
Old 02-22-2022, 04:03 PM
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Quality work for sure. Pitty for us non builders their wish there was a highly detailed composite Viggen available.
Old 02-22-2022, 05:40 PM
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Originally Posted by F900 View Post
Quality work for sure. Pitty for us non builders their wish there was a highly detailed composite Viggen available.
There is one inGermany. Very expensive ti ship as it has a one piece wing
Old 02-22-2022, 07:56 PM
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Originally Posted by Bob_B View Post
Great work. I emailed the maker about buying a kit sometime ago and they told me they were waiting for feedback, maybe you are that person. Btw Rc crafters makes a main gear set for the Viggen.
Hi Bob, I've worked with Ed from RC Crafters to produce a Viggen set in 1:9 for this model. He has made a superb set for me which I received just last week. I plan to post about these retracts and the integration into the kit shortly. I wasn't aware of Custom Wings waiting for feedback, but I heard they were interested to how Ed's design fits into the kit.
Old 02-22-2022, 10:29 PM
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Bob - Who makes it? I'd interested to know more about it.
Old 02-24-2022, 01:48 AM
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F900 I sent a PM
Bob
Old 02-24-2022, 01:49 AM
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Originally Posted by rustyives View Post
Hi Bob, I've worked with Ed from RC Crafters to produce a Viggen set in 1:9 for this model. He has made a superb set for me which I received just last week. I plan to post about these retracts and the integration into the kit shortly. I wasn't aware of Custom Wings waiting for feedback, but I heard they were interested to how Ed's design fits into the kit.
Watching this thread
Old 02-26-2022, 06:10 PM
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Default Find some Undercarriage

The internet led me to RcCrafters as they already had a 1:10 scale Viggen set on the web page.

https://rccrafters.com/#

1:10 scale set available from RcCrafters

Contacting Ed via his email lead to discussion and subsequent development of a set of a 1:9 scale Viggen set. Initially I had to join the queue as Ed had a number of projects on at the time including a very impressive set for a B-58! Ed has been awesome in creating the design to meet both the scale look together with the constraints of the Viggen aircraft itself. He always seems to be one step ahead of any idea and I’m very pleased with the results he has produced. Makes me want to build another type of aircraft just to see another undercarriage design be developed by Ed, ha ha.

Last edited by rustyives; 02-26-2022 at 10:15 PM. Reason: typo
Old 02-26-2022, 06:23 PM
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Default Viggen wing constraints

Firstly, the Viggen has a very thin wing at the section where the undercarriage attaches. I have a conventional retract set for an Xcalibur which I just dropped in for a comparison. Note the wing thickness at this location is around 25mm. Whereas a standard top mounted actuator retract unit is much more and unable to work with this kit design.

Retracts for an Xcalibur dropped in for comparison.

Too tall for a top mounted retract unit

About 35mm height on these units

The wing is 25mm maximum!

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