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  #341  
Old 01-16-2018, 07:17 PM
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Steve Melton Steve Melton is offline
 
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Originally Posted by aparchment View Post
LOL! Great idea Steve. Give her a leg up on devising practical solutions.

Thanks to you and Amanda for the printed fuel drain fairings. They fit like a glove.
Amanda says thanks. And I'll tell you that she took the money and bought another fish for her tank. It's all about plastic and fish around here.
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RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 700+ for all

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  #342  
Old 01-16-2018, 07:52 PM
Bevan Bevan is offline
 
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All this fantastic manufacturing technology is great, but has anyone calculated anticipated drag reduction and therefore increased speed?

Bevan
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  #343  
Old 01-17-2018, 04:53 AM
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Steve Melton Steve Melton is offline
 
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Originally Posted by Bevan View Post
All this fantastic manufacturing technology is great, but has anyone calculated anticipated drag reduction and therefore increased speed?

Bevan
I have not, but I am working to get CFD up and running to make an assessment.
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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 = 700+ for all

Simplicity is the art in design.

see Amanda Melton for www.rvplasticparts.com
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  #344  
Old 01-17-2018, 05:06 AM
control control is offline
 
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As it it less than 20$ in plastic and other parts if you already have a 3D-printer, I am fine with skipping the calcs and settle for testing... anything above 3 knots for the drain and flap attachment fairing would make me think it is worth it
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  #345  
Old 01-17-2018, 06:02 AM
rv8ch rv8ch is offline
 
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Originally Posted by control View Post
As it it less than 20$ in plastic and other parts if you already have a 3D-printer, I am fine with skipping the calcs and settle for testing... anything above 3 knots for the drain and flap attachment fairing would make me think it is worth it
My highly calibrated eyeball estimates that this will give you up to 4.159265359 knots.
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  #346  
Old 01-17-2018, 01:56 PM
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sahrens sahrens is offline
 
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Originally Posted by Steve Melton View Post
kicking this idea around with Amanda. maybe something like this?

Why not attach the cone to an appropriate length hex head screw that threads in from the back side to move the cone into the tie down?

Similar to the fuel drain fairing attachment but with the screw end attached to the cone.
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  #347  
Old 01-17-2018, 03:04 PM
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RVbySDI RVbySDI is offline
 
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Quote:
Originally Posted by Bevan View Post
All this fantastic manufacturing technology is great, but has anyone calculated anticipated drag reduction and therefore increased speed?

Bevan
Quote:
Originally Posted by Steve Melton View Post
I have not, but I am working to get CFD up and running to make an assessment.
Quote:
Originally Posted by control View Post
As it it less than 20$ in plastic and other parts if you already have a 3D-printer, I am fine with skipping the calcs and settle for testing... anything above 3 knots for the drain and flap attachment fairing would make me think it is worth it
I know all of this is for fun, education and, well, because we can. Given that, my unsolicited thoughts: The real question really isn't what is the drag delta from the faired tie down vs non-faired tie down ring. The real question is what is the drag reduction delta of the faired ring vs removing the ring? Is it enough to merit adding this fairing? The truth of the matter is this fairing is thought up for the purpose of keeping one from having to always remove the tie down rings. If removing the tie down decreases the drag greater than does this fairing, is the cost of the fairing justified? In $$ and in effort? I know which I would choose if the fairing increases drag from that of no ring attached?
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  #348  
Old 01-17-2018, 03:11 PM
John-G John-G is offline
 
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Steve-
First the disclaimer …. don’t own a 3D printer and know nothing about creating 3D CAD drawings, but I’m very interested in learning more about the process so have been watching this thread.

Just a thought about how one could assemble the cone/shaft assembly into the suggested housing for the tie down. The cone/shaft that goes into the tie down housing could be made from two pieces with the end of the shaft having four teeth on it that would be inserted into the cone and lock into a grove inside the cone. Once pushed in place, the teeth on the end of the shaft would provide a one-time push on assembly (but no removal). One can get an idea of what I have in mind by looking at the following photo. The locking end of the shaft could look something like the following photo but with four well defined catches instead of the two shown in the photo. After all the parts are printed the spring and cone can be installed in the housing then the shaft with the catches inserted and locked into the cone.
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Last edited by John-G : 01-17-2018 at 07:22 PM.
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  #349  
Old 01-17-2018, 06:50 PM
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Snowflake Snowflake is offline
 
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Quote:
Originally Posted by Bevan View Post
All this fantastic manufacturing technology is great, but has anyone calculated anticipated drag reduction and therefore increased speed?
One knot per SPF. That's Small Plastic Fairing. So add as many as you can, to everything that sticks out...
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  #350  
Old 01-17-2018, 08:33 PM
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Steve Melton Steve Melton is offline
 
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I like it. SPF.
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RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 700+ for all

Simplicity is the art in design.

see Amanda Melton for www.rvplasticparts.com
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