A Launch Vehicle Retrofitted to 1/25 Scale Car Models

Remember the movie Hooper, where Burt Reynolds jumps a Trans Am over a creek with the aid of rocket mounted in the hatch?

I'm "toying" around with building a model rocket launch vehicle that retrofits onto a 1/25 th scale model car kit.

It's an idea I had a few years ago.... I thought I started a thread on it but can't seem to locate it.

Nonetheless, here's a quick rendering I threw together today.

Rear-deploy recovery would be ideal. May have to make the body tube bigger to hold the laundry.

The idea is to have the rocket / launch vehicle re-usable for various different models, with kind of a bayonet mount that slides into the car / truck / battleship / whatever.

Sure, my lifting rocket could be utilized, but it is huge and dwarfs the model.

Thoughts?

I would think a 5-around-1 tubefin would be most excellent for this kind of job.

dhbarr said:

I would think a 5-around-1 tubefin would be most excellent for this kind of job.

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It seems like the tube fins wouldn't be out far enough to be past the flow pattern of the air around the vehicle?

I was thinking of a Jaguar E Type with a nice long nose, or an Auburn Boat Tail Speedster. Open both doors and fit canted tractor motors. Traditional ejection with the long nose containing the chute. Then off the back would come a plethora of mylar streamers for an awesome launch effect and lovely base drag. NO stinking fins or motors in back. Terrible for balance and fins no good in highly turbulent air flow. All gaps sealed up front with heavy plastic epoxy clay. Weight on front good.
To make stinking fins work you need them sticking way out and farther back because of your really messed up nose cone.
Sure tractor motors are silly and tails are meant for kites, but few have the courage to even be seen with such abominations. Chop that PMC!

Beware of the Myth Busters who have proven launching cars with rockets is a bad idea. Top Gear, Master Blasters and Rocket City Rednecks have had troubles too!

Daddyisabar said:

I was thinking of a Jaguar E Type with a nice long nose, or an Auburn Boat Tail Speedster. Open both doors and fit canted tractor motors. Traditional ejection with the long nose containing the chute. Then off the back would come a plethora of mylar streamers for an awesome launch effect and lovely base drag. NO stinking fins or motors in back. Terrible for balance and fins no good in highly turbulent air flow. All gaps sealed up front with heavy plastic epoxy clay. Weight on front good.
To make stinking fins work you need them sticking way out and farther back because of your really messed up nose cone.
Sure tractor motors are silly and tails are meant for kites, but few have the courage to even be seen with such abominations. Chop that PMC!

Beware of the Myth Busters who have proven launching cars with rockets is a bad idea. Top Gear, Master Blasters and Rocket City Rednecks have had troubles too!

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So would two canted tractor motors be enough? I could do that, then have them connected to a tube out the back that deploys the chute. For some reason I thought on a tractor motor set-up (3) or more was required to give thrust that balances the launch in the x and y axis.

And now that I think about it... I PM'd you about this many moons ago. I just looked... it was Dec 20, 2018. My how time flies

Thanks for sticking with the conversation. Much appreciated.

John

lakeroadster said:

It seems like the tube fins wouldn't be out far enough to be past the flow pattern of the air around the vehicle?

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Depends on the payload shape and how far away from the fins it is? Base drag approximation should tell us how far back to set the fins, noseweight shouldn't be a problem.

EDIT: assuming a 24mm body tube behind a 1:24 auto ( ~3in wide? ) then if we set the fins back only about half the car length I think you'd have a reasonable chance of success under most wind conditions.

lakeroadster said:

So would two canted tractor motors be enough? I could do that, then have them connected to a tube out the back that deploys the chute. For some reason I thought on a tractor motor set-up (3) or more was required to give thrust that balances the launch in the x and y axis.

And now that I think about it... I PM'd you about this many moons ago. I just looked... it was Dec 20, 2018. My how time flies

Thanks for sticking with the conversation. Much appreciated.

John

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Two canted motors work just fine. Duces wild or my Jack in the box oddroc. A telescoping tail would work great on this type of model too! With a telescoping tail you could configure for drag separation recovery. It works but some may consider that to be unnatural.

A bit trickier would be one canted motor and one centerline motor like on the Interceptor with add on booster.

The only axis that matters is staying firmly on the Y!

The following let's you pretty much launch anything (car, truck, boat, tank, sub, Barbie, GI Joe, Care Bear) and the ring fin doubles as a display stand.

You could extend the length and have some standard size fins for cosmetic purposes between car and ring. Put a wrap of racing scenes on the outside of the ring

https://www.rocketryforum.com/threads/hiding-your-fins-in-plain-sight-240-calories-of-fun.47954/

You can also steal from @Daddyisabar and have a simulated launch pad which actually functions as your fins

Now that is a sick idea. I love it!

The real questions are how big a motor(s) can you stick in and how far up fer the CG to balance. That is more than the Rocket City Rednecks did with the pedal car and they were bonafide PhD rocket scientists!

Find the speed of plastic!

Daddyisabar said:

The real questions are how big a motor(s) can you stick in and how far up fer the CG to balance. That is more than the Rocket City Rednecks did with the pedal car and they were bonafide PhD rocket scientists!

Find the speed of plastic!

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I need to stop by the local hobby store and pick a R&D candidate... then reverse Engineer it from there.

I threw out a bunch of plastic muscle car models when we moved 4 years ago..... I know better! The ones I kept are all 1/24th scale metal and those suckers are heavy.

Metal is good if up front! Strong and large internal volume is TIGHT!
Canted tractor motors with a centerline rear eject would be cool, but who would do a crazy thing like that?

Chitty Chitty Bang Bang would be truly scrumptious!

Do a Tesla to troll SpaceX... lol

lakeroadster said:

I need to stop by the local hobby store and pick a R&D candidate... then reverse Engineer it from there.

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My motto: When given a choice, always go for the 'Vette.


2 for the price of 1, build the convertible to launch, keep the coupe on the shelf.

Probably not what you're looking for but a top fuel dragster being long and thin would likely have the most easily stabilized shape.

Instead of a bayonet mount maybe a screw in coupler:
https://www.erockets.biz/semroc-coupler-cpl-50-screw-together-2pcs-sem-cpl-50-3ds/
Drill a hole into the back end of the model, glue the female half in. Male end glued to the booster.
Only need one male and however many female halves as you have cars.
Maybe Randy can do only females for you.
That didn't come out right.
You know what I mean.

I have always had it in the back of my mind to do a series of rockets based on various LSR (land speed record) cars.

I did a couple back in the day but they were, well, cars... I shot 'em off across the high school parking lot with varying degrees of success.

I know it isn't what Lake had in mind, but you've gotta admit that some of these would look great on the pad (Okay, so the last one is a boat. Even further off-topic than I had already dragged this thread ):

Hey Mike, some of those look very similar design wise to the Jayhawk and Evel Knievel's Sky Cycle.
Breedlove's Spirit of America looks like the Fliskits Stingray.
I'll bet that with the help of OR and some nose weight those could fly stable.

This thing always looked like a speed record car to me too...

I think you should start a build thread and at least do the Spirit of America.
That is a beautiful machine.
Might have to do some mods and make it semi scale.
OR is your friend.

Back to the muscle cars......
Sorry, Lake.

kuririn said:

Back to the muscle cars......
Sorry, Lake.

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No worries... it's all good. We went to Bonneville for speed week about 20 years ago. Everything from Model T Fords to Land Speed attempts. If you've never been there put it on your bucket list.

We saw numerous guys loose control and spin out doing speed runs. It's bizarre looking through binoculars at a car spinning, basically like doing donuts, and then within a few minutes they're driving that same car into the pits.

Back then you could just drive your rental car up, get out and watch the race sitting on the trunk of your own car. Not sure if they still let you do that or not?

Mugs914 said:

I have always had it in the back of my mind to do a series of rockets based on various LSR (land speed record) cars.

I did a couple back in the day but they were, well, cars... I shot 'em off across the high school parking lot with varying degrees of success.

I know it isn't what Lake had in mind, but you've gotta admit that some of these would look great on the pad (Okay, so the last one is a boat. Even further off-topic than I had already dragged this thread ):

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My puddle jumper, from mid '70s This time it hit some debris in the water, broke off the front floats and went airborne. Motor was a C6-7...
Tried a D12 once, too much thrust, it went into full submarine mode...
Pond too small for anything more powerful.

OMG...A Gremlin, and is that a Pacer?

Woody's Workshop said:

OMG...A Gremlin, and is that a Pacer?

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Love the Gremlin's....

I remember when I was quite a bit younger seeing on the news, some guy put a Gremlin in a concrete time capsule underground some where.
Might have been in Michigan, just can't remember. Too long ago.
He wanted some future generations to see our mode of transportation. I assume he was thinking when we all lived like the Jetson's Cartoon.
I thought to myself, that's a poor example of an average car.
I also thought that sealed up concrete, non climate controlled chamber wasn't going to leave much behind.
By the time it's found or remember, that poor car would be nothing but a rust spot on the floor.
Any normal 4 door sedan would have been a better choice as an example.
I think if the guy was serious though, he would have donated it to a museum where it would have been looked after and preserved.
Not stuck in the ground. Probably a brain fart after watching some Sci-Fi Movie. Fools and their money....

kuririn said:

My motto: When given a choice, always go for the 'Vette. 2 for the price of 1, build the convertible to launch, keep the coupe on the shelf.

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I'm all in for a Gremlin... I think I'm going to stick to my original plan and cut one out of some glued up balsa blocks. That was my original plan. A car model would be "sexier", but I'm forced into a certain scale. With the balsa wood version I can build the "scale" around some 24 mm motors.

Think "Pinewood Derby" but way... way... way cooler. And with a Gremlin that rear motor configuration will be much easier... no trunk!

Well, it isn't a Gremlin, but if you squint just a bit...