Roll Your Own: a DIY... car?

Whenever you start talking to people about General Aviation airplanes, or start reading about them somewhere, the conversation always seems to lead to Homebuilt airplanes (a.k.a. amateur built or kit planes). Homebuilt aircraft have been popular since the early days of aviation and, although they don't appear to be as prominent today because they are dwarfed by the number of commercially produced aircraft in the air, they are still a very significant share of the aircraft market.

Building your own aircraft makes a lot of sense, if you have the capability to do so. Often you are able to get much better performance for a lower price than you would with a factory built certified aircraft, such as your typical offering from Cessna or Piper. Homebuilts have to go through rigorous safety inspections before they are put to the sky, so the safety concerns that many people have about them are often moot.

So, if building airplanes is so popular, who don't people build their own cars? After all, you could reap the same benefits of lower cost, better performance, and a sense of pride that you get from driving around in something you made with your own hands. The answer is: people do. There are in fact many kit cars and scratch built cars both on public roads, and on race tracks around the world. They don't stand out very much, again due to the sheer number of factory build cars on the roads making them a fairly small percentage of the overall figures, but they are there.

I first became interested in homebuilt cars after reading Ron Champion's book "How to build a sports car for as Little as £250 and Race It!" and after competing in Formula SAE/Formula Student competitions in university. The type of car described in the book is a replica of the Lotus 7, and is now generally referred to as the Locost by its many builders. There is a large support network for builders in both the USA and in the United Kingdom.

While this is hardly the first amateur built car around, it has become a very popular option due to its simplicity and low cost. After having owned the book for many years, I decided to finally start building one this year to see how it would turn out. Over the next year or so I'll be posting occasional updates as I progress, but for now let's start with some basic Q&A.

Can it really be done for £250 (about $400 CAD)?
Short answer: probably not. The original book was published in 1996, so right off the bat inflation would have about doubled that number. But that figure probably wasn't all that realistic to begin with. Most people nowadays spend quite a bit more than that, with the low end prices in the $3000 range and the high end up over $10000. The cost to build depends on many factors such as your intended use of the car (really fast race cars using top end components generally cost more), your building skills (if you have to outsource a lot of the work it will drive up the price), and your scrounging ability (a lot of money can be saved by acquiring used parts from junkyards).

What do I need to have to build one of these?
One of the first things you will need is a donor car for the engine, drive line, suspension, and steering components. While your donor does not have to be a high performance car, there are several key things to look for. First off, it should be front engined and rear wheel drive if you plan to make a Locost. They can be made with either a live rear axle or independent rear suspension, so that's not an issue, but you have to decide which you're going to use before you start building the frame. Other things to look for are wishbone front suspension (other types are okay, but you will have to do some adaptation), rack and pinion steering, and a lightweight engine (though people do build these with V8s as well). Try to choose a vehicle which is relatively cheap and common in your area. The original book build is based on the Mk2 Ford Escort form the UK, and the Mazda Miata is popular as a donor in the US. For mine I went with a 1984 Ford Ranger pickup truck - not ideal, but it should do the trick.

Next, you will need a source of metal, and a welder or a friend who has one and is willing to weld for you if you don't know how to. Most of the metal you will need will be in the form of 1" rectangular hollow section steel tubing (about 100 feet of it). There are some parts that will require other forms of metal, such as for brackets and braces, and the book gives a more detailed bill of materials. If you don't want to do the frame fabrication yourself, and alternative is to buy a pre-made frame from sources such as Canadian Online Locost Distributors. Keep in mind that you will still have to do a fair amount of fabrication besides just the frame. Bodywork pieces that are difficult to make yourself can also be purchased from several companies, such as Kinetic Vehicles.

Obviously you need a workshop to build a car. While it's possible to do it outdoors, it's not recommended. Your workshop will have to be outfitted with basic hand tools such as wrenches, sockets, screwdrivers, etc. as well as some fabrication tools for cutting metal, drilling holes, clamping things to jigs, and so on. Having a fully equipped machine shop is not necessary, although it certainly may make the process faster and easier.

How long does it take?
Most people take at least 500 hours to build one, and if you haven't taken on a major project like this before it could take well over 1000. That being said,  your actual build time will depend heavily on how motivated you are, what level of support you have from family, your attention to detail, and a number of other factors. Many people have finished these in under a year, but conversely there are a number of projects that have been sitting in people's garages for the better part of a decade.

Is it fast?
The original Lotus was designed to be quick around the track due to its low weight. They were not very powerful cars because they didn't have to be. If you are careful, you can keep the weight of a completed Locost below 1200 lbs (about 550kg), and some even weight in at less than 1000 lbs empty (those are usually motorcycle engined builds). Even a modest 120 hp engine will produce a very good power to weight ratio of 10 lbs/hp in an average configuration. If you go all out and put a 300 hp V8 in one it will be blindingly fast - but you will also have to make it stronger.

What happens when it rains?
You get wet. If it happens enough times you may become motivated enough to design a removable soft top for it.