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Old Jul 14, 2012, 05:57 AM
Herk
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Virginia USA
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With this concept of Stuart's much of the weight will consist of the wings. So the weight will move aft with the sweep. CG change may be quite tolerable.

When the F-14 was designed two retracting trim surfaces were created just forward of the wings. When the wing swept aft, these triangular surfaces were to extend and help keep the aerodynamic forces forward to counter the effect of the wing's aerodynamics moving aft. The concept proved unnecessary and the mechanism was eventually disabled such that the surfaces just remained retracted.
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Old Jul 14, 2012, 06:06 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Mm-hadn't thought of that.I must decide on max.sweep so we can get an idea of what we're dealing with.Current stage is inserting thin carbon rods into the wings to minimise any unwanted dihedral.Would a bit of wing tip weight be advantageous?
Regards Stuart
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Old Jul 14, 2012, 08:11 AM
Just call me crash for short
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United States, OH, The Plains
Joined Jan 2011
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"Mark I like this.In fact I think it's a genius idea."

Aw shucks Stuart, don't think I'd up and go saying anything like that, but thanks.

Mark
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Old Jul 14, 2012, 09:58 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,290 Posts
Hi guys,could do with a bit of advice before I start cutting out control surfaces.I have a 600 mm length,the wing dimensions are-
Tip to pivot centre 670
Width@pivot centre. 155
Width@tip 70
Width of surfaces. 30
Drag rudders-can I leave them fixed open(if so best angle for this)
As Herks suggested earlier I propose to split the surface into 3 components.The inner 2 providing reflex in plank configuration,drag rudders at neutral.
For full sweep use the outer two to mimic twist.
Comments and advice please
Regards Stuart
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Old Jul 14, 2012, 10:08 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Quote:
Originally Posted by Quick61 View Post
"Mark I like this.In fact I think it's a genius idea."

Aw shucks Stuart, don't think I'd up and go saying anything like that, but thanks.

Mark
If this prototype flies I may have to name it Serenity, they both look as though they were built rather than designed.Just hope I don't get bits falling off
Stuart
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Old Jul 14, 2012, 10:16 AM
Herk
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Virginia USA
Joined Jun 2007
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Quote:
Originally Posted by Stupot46 View Post
Hi guys,could do with a bit of advice before I start cutting out control surfaces.I have a 600 mm length,the wing dimensions are-
Tip to pivot centre 670
Width@pivot centre. 155
Width@tip 70
Width of surfaces. 30
Drag rudders-can I leave them fixed open(if so best angle for this)
As Herks suggested earlier I propose to split the surface into 3 components.The inner 2 providing reflex in plank configuration,drag rudders at neutral.
For full sweep use the outer two to mimic twist.
Comments and advice please
Regards Stuart
Stuart - I measured the static position of the drag rudder function on the Plank. The surfaces were ten degrees above and below the neutral position - so 20 degrees of split.

If you use drag rudders like the ones on the Plank, I believe that you can put them at the outer end of the wing panel and you can still trim them up or down together to achieve various amounts of effective twist on that part of the wing whilst still retaining their drag function.
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Old Jul 14, 2012, 10:42 AM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
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If you name it Serenity, you know you will HAVE to love it.

"You can learn all the math in the 'verse, but you take a boat in the air, and don't have love, she'll shake you off just as sure as the turnin of the worlds."

Mark
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Old Jul 14, 2012, 10:43 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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Thanks Herks.How long do you think they should be?
Regards Stuart
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Old Jul 14, 2012, 11:05 AM
Herk
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Virginia USA
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Originally Posted by Stupot46 View Post
Thanks Herks.How long do you think they should be?
Regards Stuart
Well, for what it's worth, the ones on the Plank are just about exactly one-third of the panel length. Not exactly scientific eh????
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Old Jul 14, 2012, 12:05 PM
I don't like your altitude
Stupot46's Avatar
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Originally Posted by HerkS View Post
Well, for what it's worth, the ones on the Plank are just about exactly one-third of the panel length. Not exactly scientific eh????
1/3 it is.Science-who needs it
Stuart
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Old Jul 14, 2012, 02:33 PM
I don't like your altitude
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The current state of affairs.I've set the maximum sweep at 50*,used the plan of the VII for this.Drilled a hole along the centre line,used this to mark a curve to the wings plank position and slotted it out.Captive nut from below and the wing is held tight.I'll mark some points on the pivot brace and wing after Ive shaped and sanded.
The wing has had the control surface cut away;these will be replaced with balsa to aid stiffness.To this end I've also added a 1.5mm carbon rod behind the step and a second along the hinge line.
Stuart
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Old Jul 14, 2012, 05:49 PM
I don't like your altitude
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In the continued spirit of spending nowt(miserly Yorkshire tyke me)I made some horns and slotted plates.For some reason I have a bag of the small joints,1.5mm carbon off cuts will connect them.The plates will probably be lower and angled down at the front once I am sure of the geometry
Stuart
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Old Jul 15, 2012, 06:14 AM
I don't like your altitude
Stupot46's Avatar
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Spare hour or so this a/m,so inner surfaces cut and horns fitted.Tab and slot,just to be safe.The slotted plates are fitted to the wing in a similar fashion.I haven't glued these yet,taping the hinge will be easier.
Still pondering the drag rudders,I would like to be able to try closing them when the wing is swept.
The radially curved slot is for the sweep adjustment,the lines are reference points I used when drilling it out.
Weather and time permitting this thing should be in the air(or in pieces!)by this time next week.The field I intend to use never seems to get cut so nice long grass.It has a good slope and tall trees around so pretty still air on a calmish day.Downside to that is it doesn't dry very quickly,and we've had MORE than our fair share of rain this month.
Stuart
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Old Jul 15, 2012, 07:18 AM
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Stuart !! that is some very nice work there. Clever and well thought out to say the least.

Jens
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Old Jul 15, 2012, 07:54 AM
I don't like your altitude
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Originally Posted by kleinaberfein View Post
Stuart !! that is some very nice work there. Clever and well thought out to say the least.

Jens
Thanks Jens.From you that's a real

compliment.I can only do this small"fiddly"stuff in good daylight these days.
Regards Stuart
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