JEPLANS.COMRadial Air Engine

Copyright © 2012 James Eckert v7

Warning:Please take appropriate safety precautions.

Working with tools and building devices that convert energy such as engines and motors are inherently dangerous. Building and operating these devices are at your own risk.Jeplans.com or James Eckert assumes no liability for accident or injury resulting from the information provided here.

Radial Pneumatic Engine that runs on pressure, vacuum or both. These are the plans for the model engine in my YouTube Video "Rotary Air Engine" or "The Simplified Pneumatic engine and Power System". The Bellows and air rectifier are a separate free set of plans available at JEPLANS.COM.

YouTube Play lists that would be helpful for building engine:

Plans very slightly from what is pictured here.

By James Eckert

Videos related to the Radial Air Enginehttp://www.youtube.com/playlist?list=PL890FE315B9460748

Inline 4 Air Engine Construction (many of the same techniques would work for the radial Air Engine)http://www.youtube.com/playlist?list=PLB456B741C4E3CE61

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Front and back supports are cut from 1/4” Baltic Birch Plywoodactual thickness is a little less, be sure to match mortise and tenons with the thickness of your wood.

The bearings I used for the main axle were recovered for some electronic equipment their dimensions are:Inner diameter 3/16” Outer diameter 1/2” Thickness 3/8” I used a 3/16 brass tube for the axle itself.

For many of my projects ,as well as the smaller bearing in this project, I used a 1/8”ID bearings part “R144ZZ Shielded Bearing” which I ordered from Since I plan on ordering more of these I will be using them for my future engines.

Adjust the plan for the bearings and axle sizes you have.

www.vxb.com.

Drill center to match outer diameter of main

axle bearing.

Piston mount

Space

rho

le

Space

r

Space

r

Piston mount

Pisto

n m

ount

JEPLANS.COMRadial Air Engine Front Support

Spacerhole

Drill hole in piston mount to match the screw size you are using to attach piston housing

Pisto

n m

ount

Drill to match axle sizes

R3ZZ from www.vxb.com is a close match

#4 ½” slotted round head wood screw

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Copyright © 2012 James Eckert v7

Front and back supports are cut from 1/4” Baltic Birch Plywoodactual thickness is a little less, be sure to match mortise and tenons with the thickness of your wood.

Spacerhole Spa

cer

hole

Drill center to match outer diameter of main

axle bearing.

JEPLANS.COMRadial Air Engine Back Support

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Copyright © 2012 James Eckert v7

The base in my original was cut from scrap 1/ 2” plywood, use something nicer. Thickness doesn’t matter that much as long as it is more the tenon depth. Opening in middle, allows for installation and removal of flywheel.

JEPLANS.COMRadial Air Engine Base

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Copyright © 2012 James Eckert v7

Oversized fly wheel cut from 3/4” Baltic Birch plywood drill center to match main axle diameter. Try to make it snug enough so friction holds it in place but it can still be removed if needed

Radial Air Engine Fly Wheel

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Copyright © 2012 James Eckert v7

Then bore out ends(5/16”) to reduce mass.The depth shown here is not necessary, but any additional reduction in mass should be beneficial.

Make a Jig for this by drilling ½” hole through a piece of wood and cut in half to use for the clamp. Then drill a 5/16” hole through and 1/2” half way through to use as the guide. You will need to remove lip from cutting on end of piston with careful sanding so jig will slide on top.

See YouTube video “Air Engine: Piston Update” for example.http://youtu.be/3PN7jqG_8ws

allow for connecting rod attachment and

in another piece

Radial Air Engine Make Piston Jig and use (K&S #3048) to produce 4 pistons for the engine. a ½” aluminum rodSee YouTube video “Air Engine: Making the Piston” for demonstration.http://youtu.be/mpKP9n3NEhE

The valve hole in the piston is smaller on the side that will face the dual hookups. I made it a little smaller to minimize possible of air loss between the hookups.

Piston

Mount Spacer

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Copyright © 2012 James Eckert v7

Made from:1/2” X12” Aluminum Rod K&S part 3048

Drill at 15/64”, then at 9/64”

Piston Jig

37 mm

1 3/4"

0 3/4"

2 3/4"

20 mm

Radial Air Engine

Brass tube 17/32” K&S#140

Make 4 tubes

piston cylinder

End Cap

En

d C

ap

End C

ap

Piston Cylinder

Make 16 3/16” tubes 3/4” longBrass tube 3/16” K&S#129

17/32”

1”x 1 1/4” x 3/4”

1”x 1 1/4” x 3/4”

17/32”

1”x 1 1/4” x 3/4”

17/32”

�

�

�

�

�

�

�

�

�

�

�

Drill out for hole for piston cylinder 17/32”.Lightly glue inside and insert tube. Be careful not to get any glue on the inside of tube or piston will not slide.Once glue is dry, drill valve holes and clean edges of holes on inside that might catch piston. 3/16” for Smaller 2 and

3/8” larger hole.Seal grain with glue or Shelac on bigger valve holeAttach input 3/16” tubes with glue similar to with piston cylinder. Make sure no glue is pushed inside the piston

cylinder.Make end caps and output covers, attaching 3/16” tubes to them in the same manner.Be sure to drill pilot holes for screws on mount spacer to insure proper positioning.Glue end caps and output covers in placeGlue mount spacers in place, be sure to glue two on opposite sides.

Seal external grain by finishing with shellac. I used an amber colored shellac for my outer finish.In some places I used the shellac to seal the inside grain as well.

End Cap

End Caps and mount spacers are cut from 1/4” x 1” wood

End Cap End Cap End Cap Mount Spacer Mount Spacer Mount Spacer Mount Spacer

1”x 1 1/4” x 3/4”

17/32”

Output CoverOutput Cover

Output CoverOutput Cover

Output Cover

Outp

ut C

over

Mount Spacer Mount Spacer

Mount Spacer Mount Spacer

Dimensions very slightly from what is pictured.

Outp

ut C

ove

r

�Cylinder assemblies are attached in mirrored pairs.

2 Spacers should on opposite sides of the 2 other other.To make mirror sets of cylinder assemblies.

3/8”

3/8”

3/8”3/8”

3/16” 3/16”

3/16” 3/16”

3/16” 3/16” 3/16”

3/16”

3/16” 3/16” 3/16” 3/16”

See YouTube videos “Air Engine: Engine Block Parts 1-3 ” for Similar process.

http://youtu.be/-csWw7hHiFghttp://youtu.be/iZ7sra3BqCshttp://youtu.be/V_furwY_XJ0

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Copyright © 2012 James Eckert v7

If you don’t want to make the Y connectors, the same place that has the tubing will usually have them. Tubing is Vinyl .170” ID x 1/4” OD. The brass tubes in the splitters are . 3/16” K&S #129

TopTop

Side

3/4”X1” x 6.5”

�Attach interior side pattern.�Drill 1st set of side holes on top at 3/16”.�Drill interior holes at 3/8”, careful not to go all the way through. �Remove interior side pattern and attach face of wood back on with tape, do not glue yet. �Cut out triangles.

Interior side pattern

�Using wood as support, drill remaining side holes �Seal inside grain with glue or your choice of finishing like shellac, poly or varnish wood. I used thinned glue on interior pieces and shellac on exterior pieces because they dry more quickly.�Cut 3/16” brass tubs to 3/4”.�Coat exterior end of tube with glue or shellac and insert. make sure end is not plugged and let dry.�Glue top of triangle splitter on and seal outside with finish of choice.

�First attach pattern and cut off 1/8” face of wood.

Radial Air Engine Air Splitters/Y Connectors

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Copyright © 2012 James Eckert v7

In my model I used 1/16” brass tubing to assemble connecting rods and attach to the piston.These parts were cut from 1/8” Baltic birch plywood.

Drill at 1/4” to fit R144ZZ Shielded Bearing1/8"x1/4"x7/64" inchMiniature Ball Bearings

Or to match the size bearing you have.

www.vxb.com

Drill small holes at 1/16”

Radial Air Engine Linkage/Connecting Rods

The secondary axle crank was K&S 1/8” music wire about 3/4” long.

Mount Spacer

Optional, drill end that attaches to piston at 3/32” and use tube 3/32” #1268 about 3/16” long through hole for liner.

A

B

C

AC

C

Insert bearing in part B then sandwich and glue between the 2 part As, lining up center. Match narrow side with lobe that doesn’t have hole drilled.

Part Cs will be attached with 1/16” brass tubes or rods between remaining lobes.

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Copyright © 2012 James Eckert v7

Radial Air Engine Engine Hookup

Hook up as seen in video.

Just hookup one if only running on pressure or vacuum.Switching connections changes engine direction.

Spacerhole

Pisto

n m

ount

Piston mount

Space

rho

le

Piston mount

Pisto

n m

ount

Mount Spacer

Mount Spacer

Mou

nt S

pace

r

Mou

nt S

pace

r

Video for assemblyhttp://youtu.be/FfIFwj7UBJY

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Copyright © 2012 James Eckert v7