RcTek : Information & Resources for the Model Car Racer

1/5th Scale Home Built 24cc Dragster

One of the visitors to this site, Sébastien Marti, is an avid radio controlled model car collector and builder and he has assembled a collection of over 60 cars in the space of some 18 years.

This article covers the large scale dragster that he spend some six months designing and building and serves to show you can build a high performance car for very little money.

Sébastien kindly submitted the text and pictures for this article and it is also available in his native language, French. Cet article est également disponible dans la langue Française.

Click on any of the images to see a bigger version.

My Model Cars by Sébastien Marti

I am a 28 year old mechanic that has been involved with model making for more than 18 years. I have more than 60 vehicles (I don’t know exactly!), on road, off road, IC (Internal Combustion) and electric.

They have mostly been bought from shops, but some are the result of my imagination or have been inspired by other model makers that I have met via the Internet. My preferred category is the 1/8th IC circuit cars: The extreme limit.

The Dragster

Home Built 1/5th Scale Dragster

Home Built 1/5th Scale Dragster

The dragster is pictured to the right and weighs just over 6kg and is powered by a 24cc Kawasaki engine and so it performs quite well!

The article written by Sébastien is shown below.

The dragster has a 5mm thick aluminium plate chassis which is folded at the sides and the rear. Apart from the wheels and engine, all the parts of the car have been manufactured by me, nothing has been bought!

I made the nose gear and the rear axle unit, the wings are made entirely out of aluminium, the triangulated front axle mounts are manufactured from piano wire.

The Rear Of The Dragster

Home Built 1/5th Scale Dragster

Home Built 1/5th Scale Dragster

It took 3 months to plan and make the rear drive system. I used a milling machine, a lathe, drilling machines and of course a file for final fitting.

The engine has a cubic capacity of 24cc and came from a Yankee quarter scale car (Renault 21), which I prepared myself: the crankshaft was reduced and balanced, the inside of the engine was polished to improve the flow of gases.

All the power is transmitted directly to the rear wheels via an oversize chain which is kept tensioned by a derailleur unit from a bicycle.

Home Built 1/5th Scale Dragster

Home Built 1/5th Scale Dragster

The brake is rather original: an automobile fan belt is pulled into a pulley directly fixed onto the rear axle, the system is very effective and attention should be paid not to brake too strongly as the rear wheels like to pass the fronts when they are locked!

It does not have differential because a dragster doesn’t normally turn!

The rear wheels come from the “Yankee Cross Control”. The exhaust is very basic as it is just an empty tube. The fuel tank is a small aluminium bottle.

Servos & Suspension

Home Built 1/5th Scale Dragster

Home Built 1/5th Scale Dragster

Home Built 1/5th Scale Dragster

I use the same servo to accelerate and to slow down but you could control the throttle and the brake independently by using 2 servos.

With a weight of approximately 6.5kg and a rather long transmission ratio, the peak speed and acceleration are higher than those of a 1/5th scale car.

My only regret is not being able to convey to you the feelings when this 1.3 metre missile carries out a deafening run in front of you!

It does not have suspension, but the length of the frame, the flexible system of piano wire triangles at the front and the dimensions of the tyres cope very well with the defects in the road.

Summary

I spent 6 months to think about and make the dragster. I am likely to have all the tools which I need due to my work (lathes, milling machines, drilling machines, grinding machines, tools…). I work in the South of France in Toulon, my occupation involves the repair the engines (up to V18!) in boats of the French National Navy.

If you have any questions or if you want more information, please write to me;

sebastien<remove_me>marti [at] yahoo <dot> fr.

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