Timing Gear

The timing gear might seem like an unusual place to start in building a piston engine, but the reason for this is that it is fairly simple to cast. I cast it using aluminum, and i made a model out of wood which is shown below.

Timing Gear Model

Timing Gear Model

Here i have made a model of the timing gear using wood. I began by making a drawing of it on the computer, by using Inkscape’s useful render gear tool. The smaller one mounts onto the crankshaft, and the larger one is for the camshaft. The smaller one is half the size of the larger one, so when the larger one rotates one circle, the smaller one goes two. Now what i need to do is to make a sand mold of these, and cast aluminum 🙂

The Engine

Engine Intro

The engine i intend to make will be a Flat-8 piston engine which drives a propeller. I make it entirely out of scratch, and the design is made by me. Flat piston engines are good for airplanes due to their balanced weight and low center of gravity. Most parts of the engine are made by casting, and most of them are aluminum. I try to make all the large parts out of aluminum, including the engine blocks, pistons, engine heads, and timing gear to name a few. Aluminum is also a nice material to work with and cast. It will run on gasoline, and i have made a few initial calculations.

Some technical data:

  • Configuration: Flat-8
  • Firing order: 1-6-7-4-8-3-2-5 (Each 90° of crankshaft rotation one piston fires)
  • Cylinder bore: 90.0mm or 3.54in
  • Piston stroke: 82.5mm or 3.24in
  • Engine displacement: 4200 cc
Crankshaft Drawing

Crankshaft Drawing

Here is a drawing of the crankshaft. I consider the crankshaft to be the heart of a piston engine.


Firing Order Sketch

Firing Order Sketch

And just for show, this is a sketch i made when i was designing the firing order. The quality is not so good, but i made a table of arrows, each indicating the location of the crank for each piston. This shows the location of each piston in respect to a time unit i call t, each is a quarter of a turn of the crankshaft, so 8t is two turns of the crankshaft which is a full cycle for a four-stroke engine. A dot next to an arrow means it ignites the respective cylinder.


Hello, and welcome to my blog! On this blog i will be sharing with you how i will hopefully manage to create an airplane entirely from ground up. I’ve been interested in cars and engines and airplanes for a while now, so i decided to start with the big project, of actually building an airplane. Now a couple of people have successfully made a home built airplane, but most of them do not bother making an engine. I however am creating the engine from scratch. The airplane will be a four passenger one, kind of like the set up of a car. It will be a steel frame, and the main material will be wood, and maybe covered in some sort of protective carbon fiber plastic layer, and then painted to look nice. Wood was used in early aircrafts, and is now used in home built aircrafts due to its low price compared to aluminum alloys. Anyway, i do hope that you will enjoy my blog, and you can read my upcoming posts. I’ll start by building the engine.