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Normal Topic Laribee Minimum Induced Loss Props (Read 254 times)
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Re: Laribee Minimum Induced Loss Props
Reply #1 - Jun 5th, 2022 at 2:12pm
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Forming these prop blades on a 2 liter bottle as you laminate two 1/32" balsa blade forms to make one blade.
1st. Get an empty 2 liter bottle and fill it with water to keep it from collapsing when you wrap your laminated blades around it.
2nd. Mark a vertical line on the bottle (actually mark 4 vertical lines for several blades) and with a protractor mark a second line from the base of the vertical line 15 degrees to the left for the standard U.S. rotation of propellers (clockwise from pilot's position).  You can mark a second line  15 degrees to the right for a prop that rotates in the opposite direction) MARK BOTH TO AVOID CONFUSION!!!
3rd.  Get some twine, old ace bandage, strips of old "T-Shirts" to wrap the blade laminations around the bottle to dry.
4th. Cut out two balsa patterns from 1/32" balsa sheets for each blade. On one of the outside laminations mark a line from the base to the tip on the blade centerline. To align with line on bottle. Thin some carpenter's glue of your choice to laminate the blades together. 
5th. Once the laminations are stuck together and ready to place on the bottle, start placing them on the bottle at the proper angle and wrap with ace bandage (tape end of bandage to hold it in place as you place the blades) holding them in place on the bottle and let them set overnight.
6th. Once dry there are two options for mounting the blades. (1) Cut a "V" shape in the blade along the center line of the blade to mount dowel/bamboo to mount to prop hub.
(2) Take the dowel/bamboo skewer and carve, sand, saw a length of an inch to inch and a half flat to glue to the laminated blades. Leave a half an inch to mount into the prop hub, you can trim it shorter as needed later.  Assemble the blades and hub as per the Comet or Koutny style prop hubs.
7th. Sand the laminated blade and shaft to shape thinning the edges. Look at a plastic prop for ideas. 
8th. Balance the prop as you mount the blades to the hub.
  

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laminated_prop_blades_001.jpg
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If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Sky9pilot
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Laribee Minimum Induced Loss Props
May 5th, 2022 at 1:06am
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This is some illustrations of the Laribee MIL (Minimum Induced Loss) prop blades that are formed on a 2 liter bottle with the midlines set at 15 degrees to the left.  The 2 liter bottle is filled with water to keep it from colapsing and then a line is drawn on the bottle with a tilt 15 degrees to the left for counter rotating prop and 15 degrees to the right for a clockwise rotating prop.  The blades are laminated 1/32" sheets and while wet aligned with the proper line on the bottle and wrapped till dry with rubber bands or elastic strips. Then assembled on your choice of hub.  I've used tooth picks for the mounting in brass/aluminum tubing with blade angled at 45 degree angle of the blade.
  

LarrabeePropDesign_001.pdf ( 2829 KB | 19 Downloads )
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MILpicpropshapes_001.jpg
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mockupofprops_001.jpg
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freewheelingrampsrightandlefthanded3_002_002.jpg
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mockupofnewspinner_002_001.jpg
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noseblockandfreewheelingramp_002.jpg

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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