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  #241  
Old 11-18-2017, 07:21 AM
Steve Melton's Avatar
Steve Melton Steve Melton is offline
 
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drag coefficient comparison. if I remember my calculation correctly, the Reynolds number for a 0.2 inch diameter cylinder at RV speeds at 10K ft altitude = 30000. an airfoil profile shape has much lower drag than a cylinder shape for an equivalent d dimension. what's amazing to me is the drag of a small cylinder shape such as a wing bracing cable.

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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 = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
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Last edited by Steve Melton : 11-18-2017 at 07:26 AM.
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  #242  
Old 11-18-2017, 12:21 PM
sblack sblack is offline
 
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What is clear from those sketches is that anything with a wake behind it generates a lot of drag. The forward shape is not really that important within reason. If you want to go faster, fix anything that generates a wake downstream.
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  #243  
Old 11-18-2017, 04:22 PM
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Steve Melton Steve Melton is offline
 
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cool Airbus, or rather Boeing! style pics







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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 = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com

Last edited by Steve Melton : 11-18-2017 at 04:58 PM.
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  #244  
Old 11-19-2017, 11:03 AM
BHunt BHunt is offline
 
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Quote:
Originally Posted by Steve Melton View Post
cool Airbus, or rather Boeing! style pics







Any speed improvements through test flights?
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  #245  
Old 11-20-2017, 10:32 AM
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Steve Melton Steve Melton is offline
 
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planning to test this week. it's taking some extra time to fit the remaining. tweaks to the anti-rotation stop for wing structure and mod for standard cotter pin fitment. fairing position 1&6 are same but will be mirrored. bolt head to always face outboard. fairing position 2&5 are same but will be mirrored. fairing position 3&4 are same but will be mirrored. for flight testing the fairings will not be mirrored. I'm looking forward to the testing and hoping for 3 kts gain.
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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 = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com

Last edited by Steve Melton : 11-20-2017 at 11:57 AM.
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  #246  
Old 11-21-2017, 01:27 PM
WingsOnWheels WingsOnWheels is offline
 
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This may have already been mentioned, but for the type of parts I see here, PETG is probably a good material option for most home printers. PLA is easy to work with, but not really suitable for aircraft parts. ABS is good as well, but very prone to warp, and brittle. Nylon is awesome, but also prone to warp and many home printers don't really run hot enough.

After playing with PETG quite a bit, I like it. PETG is the same stuff water bottles are many of. It is more pliable than PLA or ABS, so maybe not the best for small stiff parts. However, it has great inter-layer bond and very little warp. The surface finish is not as nice as some of the others since it tends to be a bit "stringy". However, a fast pass with a torch or heat gun cleans that up. It does well in hot environments like ABS. It reminds me of a slightly softer version of polycarbonate. Extrusion temp is 235-255c, My printer tops out at around 240c and it works well.
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  #247  
Old 11-22-2017, 06:16 AM
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ABS has good strength and creep resistance. ABS is used for Lego parts. I have 40 year old Lego's that look and work like new. ABS max operating temp = 80C (176F). ABS can be more difficult to print. Once you get the print temperatures dialed in you can make some really good parts.

Position #4 fairing


First print with cotter pin access mod. Standard cotter pin fitment.
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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 = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com

Last edited by Steve Melton : 11-22-2017 at 06:47 AM.
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  #248  
Old 11-22-2017, 06:26 AM
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Nice work Steve. Wondering if you can play with a headlight mold. I was trying to fit the RV10 light Zac sells into my cowling. The shape of the base was different and I couldn't integrate it without major alteration. Give it a shot down the road
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  #249  
Old 11-22-2017, 06:34 AM
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Steve Melton Steve Melton is offline
 
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will do. I need to fit you with some of these fairings if I find 3 kts. they will not affect your paint scheme. time to install a set = 1 hr.
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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 = 900+ for all

Simplicity is the art in design.
I was born an airplane nut. I have no explanation for it.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com

Last edited by Steve Melton : 11-22-2017 at 06:38 AM.
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  #250  
Old 11-22-2017, 06:49 AM
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Vlad Vlad is offline
 
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Quote:
Originally Posted by Steve Melton View Post
will do. I need to fit you with some of these fairings if I find 3 kts. they will not affect your paint scheme. time to install a set = 1 hr.
That would be awesome. They will hide the rust as well
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