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Old May 17, 2012, 05:16 PM
Herk
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Thermal plank with drag rudders

Well I have tentatively decided to build a new wing. Actually I will be finishing a wing that I started a long time ago.

Shortly after I lost the model in the article - a great thermal plank - I decided to build another one using the same method. The new one was to be smaller and also stronger. This new one has spruce spars and shear webs - which the older one did not. I did build the wings, then got interested in something else. So for a long time these unfinished wings have been safely stored on a shelf very near the ceiling of my garage.

Now, since we have been talking about elevons that open into drag devices, and flying wings that use drag rudders coupled with the ailerons, I have become insane.

I do not want to build another model and I don't even have room to hang it up, yet I have now the obsession to see what it is like to fly a model with this feature. So, I am now working to finish this model. It will look similar to the one in the picture, but the fin and rudder will be removable. And - it will have some version of the drag elevons. How that all will be done -- I do not yet know.

I will shortly post some pictures of the work in progress - Herk
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Old May 17, 2012, 05:28 PM
I don't like your altitude
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Herks,I'm really pleased you're going to go ahead with this.Two main reasons-I was going to try it myself,but wouldn't have wanted to steal your thunder so to speak.And of course you be able to perfect the system for us
Watching with great interest
Regards Stuart
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Old May 17, 2012, 05:31 PM
Herk
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Originally Posted by Stupot46 View Post
Herks,I'm really pleased you're going to go ahead with this.Two main reasons-I was going to try it myself,but wouldn't have wanted to steal your thunder so to speak.And of course you be able to perfect the system for us
Watching with great interest
Regards Stuart
Well my friend, I may be able to do that, or report a complete non-event
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Old May 17, 2012, 05:37 PM
internet gadfly
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I have become insane.
Welcome, friend, it's a lovely place
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Old May 17, 2012, 06:34 PM
less is more
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... and I don't even have room to hang it up...
I have 2 words for you........."inflatable glider".
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Old May 18, 2012, 04:26 AM
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Ok so you have gone insane ... welcome to the club, you are in good company here. I will be watching with interest how this works.

Jens
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Old May 18, 2012, 07:31 PM
Herk
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Virginia USA
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Still mostly doing some random noodling about this thing.

I have roughed out the pod. It's roomy - I want to locate all of the servos in the pod so that I can make changes without trying to pry them out of the wings.

I was going to do wing tips like the ones in the article, but have opted for removable wing tip fins instead. There is to be a central removable fin-rudder, but by changing my idea to removable tip fins, I can make the central unit smaller. Also I can stage fin removal by leaving the tip units on for a while after I remove the central fin-rudder.

I think I can probably post some photos tomorrow. Much detail work to be done on this thing. This will be a pure plank - no sweep and no twist. Span is about 75 inches - depending on the tip arrangement. Chord is 10 inches. The weight of the wing and pod structure at this point is 14 ounces.
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Old May 19, 2012, 07:43 AM
Herk
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Just a couple of quick pictures.

The wing structure was built not long after the article I posted above. Probably it was done within a year. This wing is smaller and stronger than the one pictured, but the basic method is the same. I cut a core, sliced it into ribs and used the bed to draw the plan. The inboard ribs and balsa shear webs are doubled with plywood. All the rest of the ribs are just foam. Next step in the current process is to install the wing rods. I'll be using two 3/8 inch CF tubes for the joiners. I also need to design the fins. Oh yes, quite a lot of planing and sanding -- cough cough

Then I'll have to figure out how I'm going to work out the control systems. That'll be fun.
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Old May 19, 2012, 09:01 AM
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HerkS

Now I am subbed and this build is really got my noggin thinking as the idea of using foam ribs crossed my mind more than once ... I am watching this with great interest. BTW. is that my vision going loopy or do I see not only the PDF to the Kling but a cut-out of the plans as well?? Trying to move in on my action eh??? Go for it I say !! I had this idea while lying out in the sun today ... will have to show what I have in mind for the Kling in my thread though.

Jens
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Old May 19, 2012, 09:11 AM
I don't like your altitude
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LYING OUT IN THE SUN!!!!!! it's cold damp and overcast here,more like march than may
Herks,you will have to take more care with your pics,the arrangement was not to let Jens know about the Kling until you'd built it
Stuart
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Old May 19, 2012, 10:11 AM
Herk
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Jens -- Your vision is excellent.

Keeping up with my research on swept wings, twist and CG I wanted to see what the Kling designers came up with. To do that I had to get fairly accurate dimensions. So, I printed the plans and took the measurements.

Here is what I discovered. The twist that they show for that small outboard section of the wing is just about 12 degrees. So, as I understand the plans, the wing is not twisted until rib 20. Then all of that twist is in the portion of the wing outboard of that rib.

I did also determine that with the CG in the center of their recommended range - the static margin is 60% - surprisingly nose heavy.

I don't plan to build the Kling - your project is safe from my predation

My dream model would be an all built up balsa and open structure - span about 80 inches - sweep about 20 degrees and taper ratio about .5. Someday I will build this. -- if I survive long enough to find room for it in my shop.
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Old May 19, 2012, 10:19 AM
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HerkS.

Ah too bad I thought you might bite and try it, but your idea for a model sounds very good and if you buy a shovel and clean up the shop ... ok maybe too radical ... Maybe the Kling needs the nose to be heavy? Who knows back then they used slide rules and likely a lot of trial and error to get things to work so somehow judging by their results (over 3 minutes free flight) I would tend to think they were onto something. It is an old design so who knows. But anyway back to your build ... what are you going to cover it with, that structure sort of begs for a see-through skin to show of the fancy build style.

Jens
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Old May 19, 2012, 02:34 PM
Herk
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Hi Jens, I would not doubt their results with the Kling. If I was building one, I would definitely start with their settings. This survey of mine is mostly teaching me some things that I was not really aware of. I have found it to be most interesting.

When I cover this model, I will probably use transparent heat shrink film. However this is really just a research project - so I am using only material that I already have on hand. When it comes the time, I will see what film I have enough under my work table.

Today I roughed out the removable fin and rudder, and installed the wing rods.
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Old May 20, 2012, 06:14 AM
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Terrific, nice job, at the rate you are going it ought be flying shortly. is there going to be a cover over the BL motor or just leaving it open?

Jens
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Old May 20, 2012, 07:01 AM
Herk
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Virginia USA
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Terrific, nice job, at the rate you are going it ought be flying shortly. is there going to be a cover over the BL motor or just leaving it open?

Jens
I am planning to build a removable cowl that will fair into the spinner.

Doubt it will be very quick. When I start working out the drag elevons I think it will take some tinkering to get them right.
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