Guide line rocket car

pathtouch

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Oh wow never though of a horizontal vehicle like that! I’d love to see pics of the guide line setup and any videos of it running if you get the chance. My son’s current attention span is about three rockets at a time haha. This may add some variety to a launch morning.
 

cbwho

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I have the motor angled a bit to push downward so the exhaust doesn't touch the nylon string and there is some down force on the car for stability. I use two screwdrivers pushed into the grass on each end.

I've watched videos of the Estes drag cars and they sometimes lift on start, from photos the engines seem to be installed completely horizontal which I think is a bad design.

I don't know the optimal angle. My guess for this car is 20 degrees from level


 
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cbwho

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I drilled an exhaust hole up near the end of the bore, such that the engine must kick back a little bit. I did this since the engine is a snug fit and it helps loosen the motor while not ejecting it. If it would have ejected the motor upon testing, I would have drilled another hole. The 2x4 car is heavy and goes well on B and C motor. My son wants us to build another so we can have drag races. I am thinking of drilling the hole larger to have an injection pod with parachute like a real NHRA funny car.
 

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cbwho

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I see the cone of the fire is rather narrow also being some distance off the ground helps. I suppose the farther & rearward above the axle line, the less canting is needed as the thrust acts as a lever arm pushing the wheels down. But I wanted more margin of control. As I kid I built one with a horizontal engine and that was a fail.

On this car I used rubber wheels RC-like to aid in stability. They are from a Meccano set.
 

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tjkopena

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This is great!

With your guideline setup, does the car just crash into the screwdriver on the far side? Or you just run the line longer than the car will go?
 

cerving

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Cox used to make a guide-line dragster, there was a bead near the end of the line that shut off the engine and deployed a parachute. It was pretty cool when it worked.
 

Kelly

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I've made these before, but with a CO2 cylinder for thrust. Fun!
 

Rob Campbell

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Cox used to make a guide-line dragster, there was a bead near the end of the line that shut off the engine and deployed a parachute. It was pretty cool when it worked.
When we were growing up, we had the coolest toys hobby supplies.
 

cbwho

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This is great!

With your guideline setup, does the car just crash into the screwdriver on the far side? Or you just run the line longer than the car will go?

Mostly longer than the car will go...

I fired an A motor first then B then C. The next car will be built a lot lighter. So I will see how far the smallest motor will push it. :)
 

Cape Byron

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When I saw the photo of your car, I thought maybe it was a Tether Car. Something I've always wanted to do but rocket powered.

Not tethered via a string but tethered via a rigid pivot arm.

I saw a tether car demonstration as a kid when competing in the control line combat state championships here. They used the circular pad that the speed planes were using.

Anyhoo... totally insane. Been looking for one at the right price ever since. Seems like my right price is 'super low-ball'. 🤔 :confused:
 

lakeroadster

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I saw a tether car demonstration as a kid when competing in the control line combat state championships here. They used the circular pad that the speed planes were using.

Anyhoo... totally insane. Been looking for one at the right price ever since. Seems like my right price is 'super low-ball'. 🤔 :confused:

When I was about 6 years old Mom dug this wooden box out of the closet. It was a finely crafted box and inside it was a tether car my Grandpa Henry had. This would have been around 1967. It looked like a little sprint car (I didn't know what a sprint car looked like at the time). Grandpa Henry was one cool dude.
 

cbwho

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I thought about running this car in a tether configuration as well. As a kid, my older brothers ran a Cox air car as a tether.
 

cbwho

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indy210-1.jpg

The tether is 30 feet in length. The bridle is V shaped.

Extra care would be needed to ensure that the baseball diamond had some sort of fence/barrier to catch an errant car. I suspect that a rocket car would be safer than one of the fan Cox cars due to reduced run time. Spectators could watch from behind the catcher fence.
 

lakeroadster

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View attachment 532879

The tether is 30 feet in length. The bridle is V shaped.

Extra care would be needed to ensure that the baseball diamond had some sort of fence/barrier to catch an errant car. I suspect that a rocket car would be safer than one of the fan Cox cars due to reduced run time. Spectators could watch from behind the catcher fence.
That's an awesome photo...

I'm thinking fairly small motors, with multiple stages, cellophane taped together....
 

MadRocketer

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My son and built a guide line rocket car. We run it on a baseball diamond as that gives a very flat run.
A long while back I thought about doing this. I might still, but back then my thoughts wandered to doing this, but with boats. Like a hydroplane.
1660758995772.jpeg
(most convenient picture from the internet)
However Every scenario if ran through my mind ended in disaster so I didn’t. Still seems fun though.
 

Batjac

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I saw a tether car demonstration as a kid when competing in the control line combat state championships here. They used the circular pad that the speed planes were using.

Anyhoo... totally insane. Been looking for one at the right price ever since. Seems like my right price is 'super low-ball'. 🤔 :confused:

These days you gotta spend lots of money or luck into them. A couple of years ago I went to the local hobby shop. One of the employees knows I like to restore old model airplane engines. A guy stopped by the shop and dropped off a box of old modelling stuff. He set it aside for me, and I actually walked in about 20 minutes later. He pulled out the box, and I knew I wanted it. The box was an old Wen-Mac carton. When he opened it it was full of packing peanuts, with some plastic sticking out. Just from what I saw I knew it contained gold, as one of the plastic pieces was a teal color unique to a limited run Cox airplane from the 60's. The box had two very collectible control line planes. eBay value in the $400-$500 range. When I dug around in the packing peanuts I found a Cox Champion tether car with engine. eBay value probably in the $250-$400 range. Everything would need cleaning, but the one Cox airplane is one that I've been looking for for years. I'd also been looking for a Cox Champion tether car for a while at a good price.

What was the price I paid? I asked what he wanted for the box, so he yelled up to the front and asked the shop owner what to charge for the box. The owner yelled back $50. I pulled a frown and gave it the old, "Hmmmm, well they're pretty old and gunked up, and need work" schtick. Inside I was doing the Lindy. So I said I'd take it, and rushed the box up to the counter before they changed their mind. As I was pulling the money out of my wallet, I said, "Hmmm... There's a crack in the plastic there." I wasn't trying to bargain or anything. Not when I was getting such a steal. It was just a thought that I uttered out loud. But the shop owner said, " Yeah. It is. How about $45?" How about $45? The money flew out of my hands.

And before someone starts thinking I should have offered more, this is a shop that I've spent many thousands of dollars on over priced stuff in over the past 26 years.
 

Getmore

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I picked this one up on Ebay many years ago. Someone carved it out of wood.
 

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TigerHawk

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I picked this one up on Ebay many years ago. Someone carved it out of wood.
This picture brings back good memories. I remember back in Jr. High School (7th, 8th & 9th grade) our Science and Woodworking classes making and launching these on wire guided drag lanes. We’d have competitions with different weights of the rocket cars on Estes A, B, C and D motors.
 

GlenP

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A long while back I thought about doing this. I might still, but back then my thoughts wandered to doing this, but with boats. Like a hydroplane.
View attachment 532987
(most convenient picture from the internet)
However Every scenario if ran through my mind ended in disaster so I didn’t. Still seems fun though.
I remember a hovercraft, not sure if it would work on water without some modification, powered by a cox .049 engine. … could tether one of these, add rocket power … roads? Where we’re going who needs roads?
 

John Kemker

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Titan II

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A long while back I thought about doing this. I might still, but back then my thoughts wandered to doing this, but with boats. Like a hydroplane.
View attachment 532987
(most convenient picture from the internet)
However Every scenario if ran through my mind ended in disaster so I didn’t. Still seems fun though.
Go for it!

 

cbwho

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Progress so far.
IMG_20220823_185201.jpg
All very cool replies in this thread. I'm building a version 2.0 this time built out of more traditional LPR materials. It's 3 tubes with the middle one canted upwards to have some down pressure for stability.

Lot more flimsy but light. I hope it stays together for the ride!
 

cbwho

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I am wondering if I should install a wing to push down just ahead of the rear wheels? The uprights would also act as a rudder Thoughts anyone?

I'm thinking of running this in a tether circular direction. I'm concerned if it runs in a straight line, it'll crash majorly when/if it hits the screw driver on the end of a straight line.

Ideally I'd use rubber wheels but I couldn't find any.
received_430962052175000.jpeg
 

cbwho

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Windy day yesterday, so great opportunity to run the cars.

This quick video shows the mostly paper car hooked up with a tether. Need to remember to pull the ignition wires away!

Also, a 15 foot strong isn't long enough. The instructions above recommend 30.



Straight line guideline car:


 
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