solentlife
Some may have followed my Hawker Hunter Profile scratchbuild thread and flights.

On increasing power - I have reason to believe that elevator flex is making turns more difficult than they should.

The elevators have a serious taper to them to allow a single servo / wire joiner setup. This makes the outer tips far larger than the inner root where the horn and wire joiner are mounted.

Here's the elevator as now ... you can see the wire joiner and the horn. Also the amount of taper.

[DSCF0032_zps1p3oqmrj]

Now where would best line be for putting CF to reduce that flex ? A ... B ..... or C ?

[elevator%20CF%20where_zpsbqnymvnd]

Serious question ... and may help others with similar ?
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Sterling101
I would say probably 'C' making sure it crosses the end of the wire joiner so it transfers the loads evenly down the trailing edge.

But that's just me 😉
Whoever said nothing is impossible had obviously never tried slamming a revolving door...
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solentlife
Tricky on ... 

I pressed on the tip and it seemed to create a curved flex but really needed a lot of press to do it.

My thoughts are B or C ... and as said - close to that joiner and in my opinion needs close to the control horn.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Wildthing
Where is option D ? 
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Wildthing
On the fix part of the horizontal I would run a 3mm cf strip the width of it close to the hinge line ( 1 inch away) , then I would use option B but I would try to start right under or through the control horn. 
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solentlife
Wildthing has brought in the fixed stab and as I look through suggestions here and other forums ... the stab is coming to mind .. 

The control horn is the tab and click retainer type - so not possible to pass CF through it or under. I can only set it as close as possible to it.

On the stab though - I have been prodding / pressing etc - I think maybe the stab and elevator are moving together. Being a high mount on a narrow fin - the lateral resistance to flex is minimal - part of the reason I rejected all moving tail. I am considering glueing a triangular gusset along under the stab part to stiffen that junction. I did consider a CF all way through fin as well - but it doesn't provide wider area support like gussets.

My thinking on this has evolved .... just an idea ... so if anyone thinks different - please say so ... I want this model to fly more consistently.

When she's pushed by 4S to high speed and level ... all is OK. As soon as I bank and start feeding in elevator to turn, I wonder if the stab / elevator combo is actually flexing trying to remain level due to the increased force on it .. as the nose comes round and up - the stab / elevator combo then sees reduced force on it and she tightens the turn. Ally this with a slightly rearward CoG and it may be the reason.
If I can make the stab / elevator combo more stiff and supported better ... move CoG that few mm more fwd ... maybe that's enough ? (CF in the elevator wouldn't be wasted either).

Thoughts ??
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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solentlife
I've just added support pieces under the stab and its a world of difference. The stab is now more stable and I hope will help cure the tail problem.

DSCF0041.jpg 

Snoopy is back in his 'seat' ... 

DSCF0045.jpg 

And she's ready to try again ... (I haven't added CF ... I know I know ... )

DSCF0042.jpg 

Many thanks to all replies - they all got me thinking and trying to solve it .. 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Wildthing
solentlife wrote:
I've just added support pieces under the stab and its a world of difference. The stab is now more stable and I hope will help cure the tail problem.

  

Snoopy is back in his 'seat' ... 

  

And she's ready to try again ... (I haven't added CF ... I know I know ... )

  

Many thanks to all replies - they all got me thinking and trying to solve it .. 


99.9% of the fixed stabs I will run a cf strip in them and usually that is enough but depending on the shape of the elevator surface I may then add a cf strip to it also.  With the high mount on my Pucara I added struts to it, my first one was from the stab to the vertical but I still felt it allowed the whole vertical to twist so then I added the struts from the stab to the fuse and then it was solid. I think I could have gotten away with the latter but the other guys were already glued on so I left them there. 2018_1231_070158_002.jpg  2018_1231_145119_002.jpg    
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solentlife
As they say - proof will be in the eating !

Thanks everyone - it got me thinking hard on the subject.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Sidewayskiwi
best way ive found to reduce flex other than the standard cabon fibre/bbq skewer is the glass fibre tape/glue figlass
ontop as part of the hinge extend to cover most of the elevator assy 
at right angle junctions perfect stick your cut piece of tape right into the 90 deg juction foamtac over the top do it to both side the more you extend the stiffer the assembly
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lysle42
My test have shown the glue figlass (drywall tape) is the best weight to strength with no carbon.
Homer
<'(((><
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