Thread: Moving Car

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This is my first post (aside from introduction), so please be easy on me!

The prop that I am working on for 2011 can best be described by telling you to look up the youtube vid "High-Tech Haunted Houses" by CBS. It happens at 2 min 12 sec. (They actually use the picture on the vid description).

Now that you've watched that (need to see!), here's my plans.

I scrap metal to make extra $$, and was given a 1991 Mercury Sable. I am cutting off ALL of the car EXCEPT for the back end. So I will still have a bumper, trunk, lights, fenders, wheels, window, etc. It will be gutted leaving only what is needed for visual effect and structural integrity. (I actually have a vid of this car on youtube.... Check out my channel, HalloweenHellmouth and it's the vid of the back of the car)....

Here's how it's going to work so far... The car will be on rails, with fabricated wheels (3 sided, like a rollercoaster... for safety). I will hook up the BooBox (not yet purchased).... Continuous audio track of the car engine running, fog machine connected to exhaust pipe, tail lights/license plate lights on. When the infared sensor trips, the audio track changes to the engine revving 2 times, then the brake lights come on, then the reverse lights, brake lights go off and the car starts to come at you!

Obviously, safety is a great concern and measures will be taken. However, here is my dillema!!

How do I propel it? (cheaply) Electric motor? Ballast? Pneumatic? Hydraulic? And also, return and reset? I would like the car to travel appx 6-10 feet, which semi elimiates a $700 telescoping pneumatic cylinder...

Ideas, please!!

Thanks!!!

Depending on the weight ..........I would think an electric motor with a set of limit switches at each end to reverse and reset the prop would work. How fast do you want it to move? All the possibilites you have listed are doable, at a cost. I think I would try to figure out a total cost you want to invest and go from there. You could probably do hydraulics or air by using a variation of a 4 bar set up. This sounds very interesting , I would like to see the final result. If I can be of help PM me and I'd be glad to share some of my ideas.

Take something like a 2 by 6 ten or twelve feet long.
A turning wheel bearing assembly/axle the dead , unpowered axle. Drill the wheel pattern for the bolt holes into the 2 by 6 towards the one end. You will have to do some drawing or layout work and fasten the axle solidly into the earth or concrete. what I am trying to design with mere words is a lever that when the short end moves the long end will be traveling much, much further to give you the maximum travel from the least cylinder actuation to move the car body those 6 feet?
A welded steel frame to hold the cylinder to the axle bearing would be very nice to have after you have completely determined just how much these distances should be.
Of course the 2 by 6 could be replaced by a long piece of still soild used steel pipe, maybe around 1 1/2 inches in diameter by ? distance long.
A chain store in my area sells tractor hydralic cylinders for $50 to $75.
I put some automatic transmission fluid in them and make them work with just compressed air.
They are tremendously over-built for most haunted house uses, thereby they will last a long time and take alot of weight, torque and abuse.

Originally Posted by bfjou812

Depending on the weight ..........I would think an electric motor with a set of limit switches at each end to reverse and reset the prop would work. How fast do you want it to move? All the possibilites you have listed are doable, at a cost. I think I would try to figure out a total cost you want to invest and go from there. You could probably do hydraulics or air by using a variation of a 4 bar set up. This sounds very interesting , I would like to see the final result. If I can be of help PM me and I'd be glad to share some of my ideas.

I'm estimating the weight at appx 300 pounds. Using rubber/nylon track wheels (4 sets) should make resistance just a matter of weight.

I'm wanting it to move about as fast as a normal car would when it's first taking off (2-5 MPH?). My whole philosophy is "you can't get more real than real."

With the you-tube video: https://www.youtube.com/watch?v=ig9dhC06nwU (at 2:12) you can tell that it's not pneumatic.... There's a loud "click" such as a latch holding tension being released. That made me think of a weight ballast being used. But.... The height of the ballast would equal the length of travel, and I don't really want a pulley that can be seen... The tracks are bad enough, but I'm thinking that I can hide them with paint and grass. (This will be in my back yard).

Here's the car that will be used: https://www.youtube.com/watch?v=1MRFmIiohE0 (and yeah, that's me.......)

I'm interested in a "4 bar setup." Could you elaborate? Thanks!!!!

A chain store in my area sells tractor hydralic cylinders for $50 to $75.
I put some automatic transmission fluid in them and make them work with just compressed air.
They are tremendously over-built for most haunted house uses, thereby they will last a long time and take alot of weight, torque and abuse.[/QUOTE]


That was what I was trying to explain , you did a much better job Gym Whourlfeld. I do have a question for you though, are you using the hydraulic cylinder as an "air over oil " cylinder or a tradional hydraulic cylinder. If it is the latter , what do you use as a resivoir for the oil?

I'm interested in a "4 bar setup." Could you elaborate? Thanks!!!![/QUOTE]

I guess what I was really refering to was the "lever -fulcrum" principle that Gym Whourlfeld mentioned. I had a brain fart!!!
I think Gym Whourlfeld has the right idea and the fact that hydraulics can act faster than pnuematics is a plus in my mind. If you could even find a log splitter for sale I'm sure you could change the valve to create a faster motion!! If I had the kind of room to do this I would definetly go with hydraulics as Gym Whourlfeld mentioned. Keep us posted!!

We go through a haunted forest every year at a campground where we have a membership. One year some people took a bumper, grille and headlights from an old 60's era Ford Falcon. They simply put it on a huge swing. As a group of people riding on hay bales in a trailer would be towed past, they would let the thing go from a very dark area and swing toward the trailer. Then the headlights would come on and a LOUD horn would blast. It was crazy effective. Freaked people out. It only took a second or two for you to realize it was just a bumper and grill on a swing, but it got great screams and plenty of adrenaline pumping.

I love this idea. When you get it done, you gotta come back and post lots of video of people in panic.

It kind of appears that it may be on a slope, it's hard to see for sure. But it could be on a slope, pulled up by a winch and then released letting it free-fall down the slope, then to be winched back up. I say this because of the bounce back after the stop. It makes it appear that there is no real linkage attached to it.

You could also try to make a pneumatic scissor extender. I'd would use at least two, some real, strong pneumatic cylinders, and steel instead of aluminum.
Here's a video of what I'm talking about:
YouTube - The basic mechanics of the Scissor Prop
This one is laid down, but it works just as well pushing out instead of up.
You can download instructions from: http://halloweenpropmaster.com/sissor_prop.htm
They are very detailed, but obviously you'd need to do some heavy modification to the design to make it stronger. But the fundamentals are the same.

Also, a properly designed track and wheel system sound support the weight of the car very easily, making it so minimum force is required to actually move it. Make sure you use high strength wheels and mounts, and that your tracks are exactly parallel with each other to maximize efficiency, and thus reducing the force needed. In reality, I guess you probably could use two of the designed scissor extenders in those instructions, built exactly to the specs with a proper rail system. However, using stronger materials would make it last longer. If it's just a one year thing, I'd go the cheap route. If it is something you want to keep for a long time, go the strong route.

There was a complete truck prop pop-up that someone had built for sale last year on ebay. The other day I found a company that sells a train that pops forward like this, along with a partial car like you are using. One of the things they did so that it didn't have to go so far was to have it go through a wall panel that was cut down the center and hinged on both sides. You didn't see it until it crashed through the wall.

Another option is to use a chain drive like some security gates and garage door openers have. You could wire a motion detector or foot pad into the remote, or have someone nearby ready to activate it at just the right moment with the remote. Still another way would be to put it at the top of a slight slope or ramp so gravity would propel it down towards the victims. Then you could winch it or pull it back up. Of course it would have to be manually operated every time.