Race Mower Project

[Billh51]

My Grandson Drew and I have started a project in the shop, building a race mower. There’s a small local group that have been racing for about three years and the machines are getting a little more advanced as time goes on. I built my Grand daughter Vanessa one last year and she has done very well with it. Now it’s time to update my Grandsons machine to keep up with the rest of them.

We are starting from scratch with a bare frame and will build and machine all parts in my shop, as I had done with the previous machine. Drew is a junior in high school and takes all the shop classes available, so we are having a great time building this together. He is a very quick learner and is catching on to the lathe and milling machine, rather quickly. I am certainly no expert but I am trying to teach him the proper way do do things, while keeping shop safety at the top of the list.

I should have been taking more pictures but I have a few to start with. I may post a few more down the road as the project progresses. I will include a few pictures of the one I built last year. My Grand daughter Vanessa did help build her machine but not to the extent of machining the parts.

 

[Cadillac]

I like the heim end configuration on the front end. I wish we had that around our area looks like lots of fun. Good job!

 

[eugene13]

Looks like the beginnings of a real race mower, keep the pics coming.

 

[kd4gij]

 

[Billh51]

I had forgot about that’s episode, funny stuff.

 

[Billh51]

We made a little more progress on the race mower over the weekend. Got the wheel studs pressed into the hubs and started machining the rear axle. We were able to mock up the rear axle to help set up the Ackerman for the front axle. One small step at a time.

 

[Joe in Oz]

Thanks for letting us watch your progress!
A question: most cars have the "king pins" or steering knuckles close to or on the centre line of the hub. Gokarts and your race mower have the whole steering mechanism on the insed of the wheels - even some distance away from the wheels. I don't understand why. That would increase the forces on those pivots enormously and make the Ackerman steering geometry seriously ineffective, as the wheels go around an arc, rather than pivot around their centre line as Ackerman would have anticipated. Is it a fabrication issue or a racing geometry reason?
Cheers,
Joe

 

[Billh51]

Thanks for your reply Joe. I'm kind of new to this myself but after doing a lot of research on race mowers, this is how they do it. I understand what you mean, thinking it may just bind up but it seems to work. My Grand daughter won both her heat races and the feature, first time out last year. The mower handled like a dream, very smooth in the corners. She lapped all but the second place mower. This one is built very similar but with more adjustability in the front end.

These mowers are very rigid, ideally no flex in the frame. When you turn left, it hikes up the left rear tire and lowers the right front. This helps turn the mower and puts all the bite on the right rear. You can drive it pretty deep into the corner. At least it all sounds good on paper, right? Lol

 

[FOMOGO]

Great job on your grand daughters ride. Are there any rules regarding engine use and modification? Cheers, Mike

 

[Tozguy]

Are you allowed to tweak the cutting blade for better ground effects in the straights?