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  #321  
Old 01-03-2018, 01:11 AM
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shadowbrush shadowbrush is offline
 
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Quote:
Originally Posted by Steve Melton View Post
how to explain the deviation of the fairing to the right at flying speed?
Might be prop wash.

Holger
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  #322  
Old 01-03-2018, 02:08 PM
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Steve Melton Steve Melton is offline
 
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I thought the vane would be mostly straight aft or slightly trailing edge to the left because of prop rotation. I was surprised that at lift off speed the trailing edge moved to right. It must be the prop but I don't understand the flow stream.
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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all

Simplicity is the art in design.

Last edited by Steve Melton : 01-03-2018 at 02:11 PM.
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  #323  
Old 01-03-2018, 08:56 PM
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Of course, now that you know where the wind is blowing from, you could rotate the naked antenna to the right and reap the massive drag reduction.
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  #324  
Old 01-05-2018, 05:34 PM
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Steve Melton Steve Melton is offline
 
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Default shirt hanger mount

perfect fit and secure. will not damage sheet metal since only one side has tang against a flat. I'm happy with it. Keeping cost and weight low with simple eyebolt and nut.



overload to maximum, springs back to original.

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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all

Simplicity is the art in design.

Last edited by Steve Melton : 01-05-2018 at 05:45 PM.
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  #325  
Old 01-06-2018, 04:56 AM
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humptybump humptybump is offline
 
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Quote:
Originally Posted by shadowbrush View Post
Of course, now that you know where the wind is blowing from, you could rotate the naked antenna to the right and reap the massive drag reduction.
Dan, I would have expected you to propose adding a micro servo drive motor with torque sensor feedback so the bane could auto trim.

Edited: (Oops, not “Dan”. I folded two threads ... almost as dangerous as crossing the streams.)
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Last edited by humptybump : 01-06-2018 at 12:26 PM.
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  #326  
Old 01-06-2018, 12:20 PM
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Quote:
Originally Posted by humptybump View Post
Dan, I would have expected you to propose adding a micro servo drive motor with torque sensor feedback so the bane could auto trim.
Glen, I don't know who Dan is, but find your approach quite reasonable. And may I suggest the simple addition of using your sensor feedback to also drive a dedicated rudder trim tab (with indicator) and ensure coordinated flight? It's the little details that make a superior craft.

Holger
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  #327  
Old 01-06-2018, 12:31 PM
rv7charlie rv7charlie is offline
 
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Is the material not strong enough to print the eyebolt, too?
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  #328  
Old 01-06-2018, 12:54 PM
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nope, a 1/4 inch dia long bolt is not a good application for ABS. the overload test placed several hundred pounds on the bolt.
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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all

Simplicity is the art in design.
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  #329  
Old 01-14-2018, 11:43 AM
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Steve Melton Steve Melton is offline
 
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Location: Cincinnati, OH
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Default tie down eyebolt fairing

eyebolt model weight = 30 grams

actual part weight = 30 grams

this is the not the fairing but rather the hardware that it will attach.

http://www.cleavelandtool.com/Stainl.../#.WluW4K6nGUk





Since I jack on these tie downs I wondered of their load capability. 600 lb applied at the very edge of the lower hole resulted in high stress. Stainless 316 annealed bar used in the analysis (I don't know which stainless they use for mfg so I chose a low grade to be conservative), material properties of 75 ksi ultimate and about 30 ksi yield and a lot of ductility, around 30% elongation to failure. The results show permanent deformation may occur but nothing close to failed condition and the stresses will redistribute quite well. So, the message to me is to be sure to have a rounded shape jacking feature, like a cup, to distribute the load around the lower ball surface. The good news is that the thread and shank are overall more robust but a couple local areas may have slight yielding. I still plan to use these for jacking but I'm not going to be jumping up and down on the wing at the same time. <smile>

Elastic analysis - pseudo stress

boundary condition. red area is thread - sliding/fixed, green area is 600 lb towards the thread


displacement


stress


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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all

Simplicity is the art in design.

Last edited by Steve Melton : 01-14-2018 at 10:50 PM.
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  #330  
Old 01-14-2018, 10:39 PM
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Steve Melton Steve Melton is offline
 
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Default Plastic analysis - stress redistribution

this is a plastic analysis for 30 ksi yield strength and the corresponding strain. this is what really happens as some of the local high stress areas yield. the stress redistributes. the local strain areas are prone to cracking after many cycles. It should not be a problem for this application because the cycles are low and the strain values are also low and the material has good ductility. I am confident I can use these for jacking points for the life of the aircraft.

stress


plastic strain - these are the areas to inspect for cracks. the risk of developing cracks is very low unless there is some material defect.


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Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all

Simplicity is the art in design.

Last edited by Steve Melton : 01-15-2018 at 07:48 AM.
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