Hodgson 9-Cylinder Radial Engine

Overview
Construction Logs
Links to Resources
The CAD Files
Disclaimer

Recently Updated Construction Logs

079-083 Oil Pump Gears & Shafts Sat, 13 Oct 2012
077 Oil Pump Housing Sat, 13 Oct 2012
064 Cylinders Sat, 13 Oct 2012
023 Crankcase Housing Sat, 13 Oct 2012
019 Cam Gear & Assembly Sat, 13 Oct 2012
018 Cam Sat, 13 Oct 2012

Overview
Lee Hodgson's late father, Sam, created this wonderful scale engine beginning way back in 1936. Lee has reworked the plans, and now offers a thick tome of CAD drawings and all the necessary information to re-create one of these masterpieces available at AgelessEngines.com. With thousands of construction hours, it is truly a masterpiece of both skill and perseverance.

The plans for the Hodgson radial are produced by CAD and are very well done. The are some minor mistakes throught and I'll try to point those out as I progress through the construction on these many pages.

When starting any machining project, and most certainly one of this magnitude, I like to construct a complete 3D CAD solid model. Most of the time, the sequence of creating a CAD solid is very much like machining. You start with a rectangular block, and subtract cylinders to make holes, fillet and chamfer edges, and subtract other rectangular regions to make slots and cut-outs. I find that thinking how to draw these different CAD parts gets me 90% of the way to knowing how to fixture, hold, and the sequence of machining operations needed to make the actual parts. It's also an excellent check on all of the dimensions as well as a great tool for understainding how all the parts fit togather, and what dimesions are critical and which ones are not.

I spent over 100 hours just creating the solid model of this engine in AutoCAD, and many more making small changes and "improvements!". I'd love to be able to share this model with everyone, but the Hodgson's have put a lot of work into creating this wonderful engine so, you'll just have to buy the plans from them and create your own. As I pointed out earlier, building the CAD model is a great learning experience, so you'd probably want to do it yourself anyway. While I'm unable to share my complete model, I will be posting CAD models of special tools and modifications I've made.

Construction Logs
I've broken down the parts into function related groups. In each group, I'll be creating pages for the individual parts documenting the fabrication of each part starting with the CAD model. On the left in each group is an image of the CAD model for that part group. Moving your mouse over the individual part links to the right of the image will highlight that part in the model. If the part has a construction log, you can click on the part number link to go to the log.

Guide to the construction logs below:
    Finished parts have no decoration
    • Denotes work in progress
    ~ Denotes pages coming soon

The Cooling Club

~001 Cooling Club
~002 Rear Mounting Hub
~003 Front Mounting Hub
~004 Hub Key

The Front Crankcase Cover

005 Bearing Retaining Plate
007 Front Cover

The Cam Retainer Assembly

008 Retainer plate
009 Pad support
010 Retainer pad
012 Spacer

The Jackshaft Assembly

013 Jackshaft
014/015 Gears S-2412/G-175 & Assembly

The Cam Assembly

018 Cam ring
019 Gear G-677 & Assembly

The Main Bearings

021 Front bearing
022 Rear bearing

The Crankcase

023 Housing
024 Cylinder flange stud
025 Tappet bushing
~026 Pushrods
027 Tappet

The Oil Sump Assembly

028 Body
029 Drain tube
030 Scavenge tube
031 Main cap
~Assembly

The Crankshaft Assembly

~032 Front crank
~034 Bearing sleeve
035 Crank cheeks
~036 Main journal
~037 Rear crank
~039 Gear H-3230
~041 Gear G-481Y-P
043 Impeller

The Rods

045 Master rod
046 Rod bearing
047 Slave rods
048 Slave rod pins

The Pistons & Rings

050 Pistons
051/052 Wrist pins & buttons
~053 (old 47) Compression ring
~054 (old 48) Oil control ring

The Cylinder & Heads

055 Head
056 Valve seat
057 Head gasket
058 Valves
059 Valve spring cup
061 Valve spring retainer
064 Cylinder
~Lapping the Valves

The Rocker Arms

065 Base
066 Arm
067 Pivot pin
069 Adjusting Screw

The Intake & Exhaust Pipes

~070 Intake pipe
~071/072 Exhaust pipe
073 (old 68) Mounting plate
074 (old 69) Crankcase mount
075 (old 70) Gasket

The Oil Pump Assembly

077 Housing
079 Gear, driven G-174
082 Gear, pressure G-163
083 Gear, scavenge G-165

The Oil & Fuel Supply Lines

~084 Transfer pipe
~085 Transfer fitting

The Rear Seal Plate

087 Plate
090 Spacer

The Rear Crankcase Cover

091 Cover casting
092 Air guide
095 Carburetor Mount
096 Locking cylinder

The Electronic Ignition

The Oil & Fuel Tank

The Mounting Stand

Appendix

CAD Files

Disclaimer and License
All material, including the CAD drawings, relating to the construction of the Hodgson Radial presented on this site is free to use any way you see fit. However, no guarantees are made regarding the accuracy or correctness of the material presented here.

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