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Rans S-9 Chaos. Peter Miller's new design blog


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Started studying the enlarged plan to make a shopping list. I found something I do not understand related to the removal of the wing:

 

image.png.c8a5de02f3bc9adc5979462880346b7d.png

 

The ruler resembles the wing being rotated (the dowel is still in the hole) until it can slide far enough back to release the dowel. However, when the wing rotates

the top of F3A (indicated by the pencil) come forward and clashes with F3. It looks like the wing cannot be removed this way.

Since others have build the S-9 it obviously can, so I am missing something. But what?

Regards, Lucas

 

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The former is only 1/8" thick, It allows the wing to rotate enough to pull out.

 

Lets put it this way. My wing comes off with no trouble. Mick King's wing comes off with no problems.  I cannot see why your would not.

 

It is exactly the same system as all my similar models

 

 

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5 minutes ago, Peter Miller said:

The former is only 1/8" thick, It allows the wing to rotate enough to pull out.

 

Lets put it this way. My wing comes off with no trouble. Mick King's wing comes off with no problems.  I cannot see why your would not.

 

It is exactly the same system as all my similar models

 

 

I now see my thinking error: The wing will begin to slide back as soon as one begins to lift the trailing edge. Thereby creating room in the front for F3A to rotate without being stopped by F3. 

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I think I can see your problem.

If you make everything a perfect tight fit and if you make the front dowel exactly .25 inches and ream the hole to exact .25" size then there will be no tiny amounts of room for any movement. I have yet to meet a model with that degree of machined precision.

With tiny little bits of play and slop in every joint it works.

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The wing dowel hole doesn't need to be circular. It can be a slot as the only critical dimension is where it holds the wing in position - in this case the top.  I bought the CNC cut parts from Sarik and the pre drilled hole wasn't exactly right (or my building made it so!).  I just added a cross piece of balsa and the wing fits perfectly  - held in place by the dowel, the wing seat and, of course the 6mm wing bolt.

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The hole is not the problem. It is that the canopy cannot rotate around the front bottom corner without the top of F3A going forward, which it cannot due to F3. But if the canopy slides backwards at the same time as it rotates it should not be a problem. And given that it in practice has shown not to be a problem I should stop pondering and start ordering wood....

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  • 2 weeks later...
  • 1 year later...

I have returned back to RC flying after a break of about 30 years. I used to own and fly what is now the only Rans S9 left in the country. I managed to find the S9 drawings and ordered a back copy of RCM&E. I christened mine 'Tweety' and had an image of Tweety Bird on the tail. I purchased it off the original builder, who decided on a 'high back'. The engine was a Rotax 532 water cooled with an under slung radiator. I might do the cockpit area as open as possible with a rigid wire cage glued on place . Because it has wing struts, this would need them to be a stressed member. Time will tell.

 

A big thanks to Peter Miller for a very good set of drawings.

 

I include a couple of photos below, but have a lot more detailed ones if anybody is interested. I am happy to answer any questions regarding the full size plane.

 

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DSC_0098.JPG

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That is great!!!  I am so glad that you approve of my drawings.  

My model was based on one owned by an New Zealand  owner living in Taiwan who provided the colour scheme photos. 

 

Of course you will base yours on your won full size aircraft.

 

I can say that mine flies like a dream and another club member built one and loves it.

 

Had I seen your colour scheme I would have used that instead.

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Yes, my model will be based on the full size one I owned.

 

The full size one was a challenge to fly, so I am pleased that the model has better manners.

 

I will update this thread with more pictures as the build progresses, but it will probably take quite a while as it competes with other non flying projects.

 

Edited by Peter Hothersall
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