- Joined
- Mar 9, 2018
- Messages
- 465
Episode 1 || Introduction to My Build Thread
Background
After a brief search through the H-M.com archives, I was a bit surprised that nobody had documented their journey building an Edwards Radial 5-cylinder engine. These engines are reasonably complex and time consuming to construct, but as (1) detailed drawings are freely available and (2) it's a 'billet engine' requiring no castings, it tends to be a project commonly tackled by hobbyists like us (here's one nice example). There are several build threads for the Edwards in other forums, but apparently not here. UNTIL NOW!
The engine is a 5-cylinder radial designed and developed by Forest Edwards in the late 1980s. Edwards built about 30 of them for use in large-ish scale model airplanes. Robert Sigler drew up a set of plans (39 sheets total) for the engine in the early 2000s, which will form the basis of my build.
Overview of Engine
The Edwards is a methanol/nitromethane-fueled, glow-plug ignition, 5-cylinder radial engine with an overall diameter of about 10" and total displacement of 3.4 cubic inches (56cc). Running optimally, it reportedly spins a 22" propeller something like 6,000 rpm*. It packs a serious punch! The Edwards relies on a dry sump lubrication system to pump castor oil to the moving bits. The valve train in comprised of an intake and exhaust valve in each head controlled by pushrods activated by a 'cam ring' running concentric with, and geared to, the crankshaft.
Intent of this Build Thread
I hope that this build thread will serve several purposes:
Side notes:
(1) I started this build about a month ago, so several components are already done. Accordingly, my first few posts after this one will be in pretty rapid succession, as I have time to write them up. Things will slow down precipitously after that.
(2) I have a full-time job, a 2.5-year-old son, a 1-month-old daughter, and a honey-do list a mile long. Shop time is hard to come by. Bear with me if there are stretches of inactivity...
*Edit: I originally said that this motor can produce 6HP based on something I recall seeing online. I can no longer find reference to that stat anywhere. I don't think I made it up, but perhaps I did. Let me know if you see the peak power referenced anywhere online by a reputable source.
![PK2a.jpg PK2a.jpg](https://www.hobby-machinist.com/data/attachments/282/282332-7bed27714a2654acf6a48be3fa4a7fe8.jpg)
![Drawing snip 01.png Drawing snip 01.png](https://www.hobby-machinist.com/data/attachments/282/282333-022eecb2bfa369cb90a4c4c2bbb6bc77.jpg)
![Drawing snip 02.png Drawing snip 02.png](https://www.hobby-machinist.com/data/attachments/282/282334-379b1894a8d21c03094a01e055eec0b6.jpg)
Background
After a brief search through the H-M.com archives, I was a bit surprised that nobody had documented their journey building an Edwards Radial 5-cylinder engine. These engines are reasonably complex and time consuming to construct, but as (1) detailed drawings are freely available and (2) it's a 'billet engine' requiring no castings, it tends to be a project commonly tackled by hobbyists like us (here's one nice example). There are several build threads for the Edwards in other forums, but apparently not here. UNTIL NOW!
The engine is a 5-cylinder radial designed and developed by Forest Edwards in the late 1980s. Edwards built about 30 of them for use in large-ish scale model airplanes. Robert Sigler drew up a set of plans (39 sheets total) for the engine in the early 2000s, which will form the basis of my build.
Overview of Engine
The Edwards is a methanol/nitromethane-fueled, glow-plug ignition, 5-cylinder radial engine with an overall diameter of about 10" and total displacement of 3.4 cubic inches (56cc). Running optimally, it reportedly spins a 22" propeller something like 6,000 rpm*. It packs a serious punch! The Edwards relies on a dry sump lubrication system to pump castor oil to the moving bits. The valve train in comprised of an intake and exhaust valve in each head controlled by pushrods activated by a 'cam ring' running concentric with, and geared to, the crankshaft.
Intent of this Build Thread
I hope that this build thread will serve several purposes:
- First and foremost, I hope that the mere fact of starting it will keep me motivated throughout the process, and help ensure I end up finishing it.
- Second, everyone on H-M likes a good build thread chock-full of photos, both for the entertainment value and for helping others undertaking a similar project; I intend to include lots and lots of photos along the way.
- Finally, one thing that I wish other build threads had is an accounting of how much darn time everything takes. Is it just me, or do even seemingly simple components take a very long time to make, particularly if there's any special setup requirements? I'm reasonably new to the hobby, so it could be that I'll get faster as I go, but it's hard to believe I'll get much faster. Anyway, I intend to keep rough track of how much time each component takes, and a running total of how long the whole build is taking.
Side notes:
(1) I started this build about a month ago, so several components are already done. Accordingly, my first few posts after this one will be in pretty rapid succession, as I have time to write them up. Things will slow down precipitously after that.
(2) I have a full-time job, a 2.5-year-old son, a 1-month-old daughter, and a honey-do list a mile long. Shop time is hard to come by. Bear with me if there are stretches of inactivity...
*Edit: I originally said that this motor can produce 6HP based on something I recall seeing online. I can no longer find reference to that stat anywhere. I don't think I made it up, but perhaps I did. Let me know if you see the peak power referenced anywhere online by a reputable source.
![PK2a.jpg PK2a.jpg](https://www.hobby-machinist.com/data/attachments/282/282332-7bed27714a2654acf6a48be3fa4a7fe8.jpg)
![Drawing snip 01.png Drawing snip 01.png](https://www.hobby-machinist.com/data/attachments/282/282333-022eecb2bfa369cb90a4c4c2bbb6bc77.jpg)
![Drawing snip 02.png Drawing snip 02.png](https://www.hobby-machinist.com/data/attachments/282/282334-379b1894a8d21c03094a01e055eec0b6.jpg)
Last edited: