Mounting Dozer Blades On Hovercraft?

[Dayton3]

I have an anthology collection of Hammer's Slammers stories (Hammer's Slammers is a science fiction universe by David Drake that features a mercenary tank unit centuries in the future) and it has a diagram of one of Hammer's hovertanks.    Now the tanks are 170 tons,  powered by a fusion reactor so they are not that different from Battletech technology.

Anyway the diagram shows attachment points for a dozer blade on the hovertanks.   Now,  I know our own modern tanks can mount dozer blades to help them dig in to firing positions.

But to my point,  can you actually mount a dozer blade on a HOVERtank and use it to actually move substantial amounts of Earth?    I wouldn't think so as you need treads or wheels to provide traction and transfer the force of the vehicle moving forward to enable the blade to cut into the Earth.

[CrossfirePilot]

I would think you would have to have something akin to treads to work with as well. Newton's third law and all that.  Unless on the back of the tank there were a couple large jet engines.  But then I would think that they would cause the blade to dig in and then flip the tank over....

[Empyrus]

I would think you would have to have something akin to treads to work with as well. Newton's third law and all that.  Unless on the back of the tank there were a couple large jet engines.  But then I would think that they would cause the blade to dig in and then flip the tank over....

Careful thrust vectoring can probably solve that, along with careful positioning of the said engines.

But really, if one is building that complex dozer, they probably need to rethink what they are doing and why they are doing that...

Hovercraft don't make for very good work platforms, except for transporting stuff that needs to be transported quickly and possibly over water.

[Tyler Jorgensson]

Condor TransTrack  .... just saying.....

[Empyrus]

Yeah, well, that thing was a boondoggle, wasn't it?

[YingJanshi]

Could you use the dozer blade on a hover for clearing barricades or other improvised obstructions?

[Alsadius]

Could you use the dozer blade on a hover for clearing barricades or other improvised obstructions?

A hover does have some forward thrust, so it can push some things out of the way. But not very much, because it has no ability to gain traction - it can't lean or push off the way a ground vehicle can, it can only thrust. So if you were trying to drive a hovercraft through a sheet of plywood, sure, it'd work. It might even do okay as a snowplow, though the idea of a hover-snowplow is just silly(why does the hovercraft care?). But against anything solid, it'd be dramatically inferior to a wheeled/tracked vehicle.

[Tai Dai Cultist]

Could you use the dozer blade on a hover for clearing barricades or other improvised obstructions?

This is what I'm imagining the pic is alluding to that is referenced in the OP. (can't link it here, stupid pinterest. :P )  If the pic he's talking about is the one I'm thinking it is, the annotation is thus:

Armoured Prow: Some tanks have a bulldozer blade mounted here.

"Here" as referenced in the pic, btw, is a small horizontal protrusion that really appears to have no function (hence the helpful illustration note).  Still, I get the idea from the picture that while dozer blades are sometimes employed, it's neither permanently mounted nor widespread in practice.


While hovers don't have much of anything in the way of surface grip and that'd mean earth moving is a terrible idea, I agree with YingJanshi in that there's lots of things you can do with a bulldozer blade besides earth moving.  170 tons still imparts a LOT of force.. plenty sufficient to clear loose debris and barricades only meant to stop/slow down infantry.  Perhaps clearing barbed/concertina wire is reason enough to have the capability.

[Dayton3]

You know its possible that the dozer blades that could be mounted on the Slammers tanks were for pushing aside mines.

I would assume that brushing aside mines laid on the surface or just below the surface would be possible for a dozer blade on a hover tank.

[Alsadius]

You know its possible that the dozer blades that could be mounted on the Slammers tanks were for pushing aside mines.

I would assume that brushing aside mines laid on the surface or just below the surface would be possible for a dozer blade on a hover tank.

It might be possible, but it's really difficult. Dirt is really heavy, and that's even before you need to break up tree roots and the like. I wouldn't advise trying, especially when you're talking about a mine that probably won't go off for a hovercraft in the first place.

[Weirdo]

If you wanted to minesweep with a hover, you'd probably be better off with a flail or roller-type device than a plow. You're just not going to be able to do any type of digging while hovering, even just a little below the surface.

I do like the idea of using a dozer blade for clearing light barricades or barbed wire, though. A hovercraft weighing a few dozen tons should be able to handle that stuff easily, especially once it gets up to speed and F=MA is on your side.

[Dayton3]

So the consensus then is that for serious bulldozer work (at least several inches deep) that a blade on a hovercraft would be ridiculous?

I guess then it would also be foolish to have farms in Star Trek with antigravity hovercraft pulling plows?

[Weirdo]

Can't really say anything on that without knowing more. If the Trek hoverplows have some sort of technobabble about being able to push against a planet's gravitational field or something, that'd give it the leverage it needs.

In a relatively hard-science setting like Battletech(yes, you're allowed to laugh here), hover plows or dozers don't seem practical.

[ColBosch]

It would work in Trek, because they specifically have tractor/repulsor beams that can exert physical force. Earth-moving blades would not work on hovertanks in the (ugh) "Hammerverse" because of simple physics. A hovercraft is going to need to exert force equal to its mass plus the mass of what it's shoving, plus friction works for the dirt and against the hovertank. Here's a visual reference:



A tank on a tractor-trailer. It's not an unusual amount of truck. A few more wheels than normal, just to spread out the mass, but you wouldn't look at that and say, "wow, look at all that truck."



A tank on a hovercraft. It takes an enormous hovercraft to carry one tank. Holy crap, that it is a lot of hovercraft.

...actually, I cheated there. The tank in the first image is an M1A2 and the tank in the second is an M1A1. The A2 weighs about ten tons more than the A1 and cannot be carried by the hovercraft at all.

[Dayton3]

While we're crossing science fiction universe lines anyone familiar with the Bolo combat units (monstrously huge,  fusion powered super tanks, thousands of tons,  controlled by advanced artificial intelligence) by Keith Laumer?

There are several Bolo stories where giant dozer blades and plows are hooked to Bolo Combat Units.

[idea weenie]

The Bolos are tracked units, and large enough that all the Bolos have to do is plop down on the ground and use giant winches to pull gang plows.


Now what I could see is a modification where there are cutting systems on the front of the plow for the barricades.  Figure a large chainsaw with a system to cut barbed/razor wire that it runs into (instead of the chainsaw setup getting it jammed inside, like this).

So heavier than the bulldozer blade, but give it a bonus to removing obstacles?  I'm about to make another Fan Design.

[Luciora]

Any design moving at sufficient speed and of descent mass can move large amounts of earth,  once.

[Dayton3]

The Bolos are tracked units, and large enough that all the Bolos have to do is plop down on the ground and use giant winches to pull gang plows.

.

Now that was a great story!!   "The Ghost of Resartus" I think it was.

[mbear]

You know its possible that the dozer blades that could be mounted on the Slammers tanks were for pushing aside mines.

I would assume that brushing aside mines laid on the surface or just below the surface would be possible for a dozer blade on a hover tank.

It's been a few years since I've read the Slammers novels but I could swear their hovertanks used a rocket deployed explosive net to clear mines. Something like the MICLIC.

Could you use the dozer blade on a hover for clearing barricades or other improvised obstructions?

Something like the cow-catcher used on trains?

[kato]

Something like the cow-catcher used on trains?

One idea: You might want to clear underbrush ahead of the hovertank - including small rocks- so they don't damage your hover mechanisms when you drive over them. Could be a possible application for something similar to a dozer blade.

In BT terms, dozer blades on hovers as a chassis modification for allowing entry into light woods terrain? (small hover support vehicles have the monocycle chassis mod for that)

[Demon55]

As someone who does construction oversight...  I have noticed it takes heavy vehicles to move earth that are heavy and have torque.  A hovercraft I would expect to have a very hard time pushing dirt. 

[ColBosch]

I was reading through some Renegade Legion: Centurion stuff, and their grav engineering vehicles use magical force fields to push dirt around. That's probably what you'd need.

[THEMONSTER]

I seem to recall in the Hammer's slammers story hangman, the blower tanks where smashing there way through a forest (of explosive trees no less) with said dozer blades.  But than HS is not exactly hard sci-fi.

[mbear]

One idea: You might want to clear underbrush ahead of the hovertank - including small rocks- so they don't damage your hover mechanisms when you drive over them. Could be a possible application for something similar to a dozer blade.

In BT terms, dozer blades on hovers as a chassis modification for allowing entry into light woods terrain? (small hover support vehicles have the monocycle chassis mod for that)

Sounds like a giant Dyson Air blade. You'd have a long thin strip of an opening, then push a bunch of air through it.

[Dayton3]

I seem to recall in the Hammer's slammers story hangman, the blower tanks where smashing there way through a forest (of explosive trees no less) with said dozer blades.  But than HS is not exactly hard sci-fi.

How is "Hammer's Slammers" not hard science fiction?

[kato]

Sounds like a giant Dyson Air blade. You'd have a long thin strip of an opening, then push a bunch of air through it.

I was thinking more like this hovercraft mowing machine.

[Hellraiser]

My guess is the blade isn't for construction level "bulldozering".

Its not in any of the pictures that I can find & only a couple of them have the armored prow that it mounts too.

I'm betting is a limited use item for some of the functions mentioned above.

1.  Trigger "rod" mines early
2.  Push aside minor debris that would damage the skirts.
3.  Clearing those exploding trees mentioned above would be a combo of both the above functions.
4.  Shove a car out of the way to allow the tank column to move past.
5.  Another thing that popped into my head is angling it backwards & under the lip of the skirt just a few inches might allow it to act like a skid plate or ramp when crossing over something that wont come up easy like a tree stump.   Would be a rough ride as you are doing some "mini jumps".   At least that is what I'm picturing in my head.  Though it would probably just end up turning them over onto their side, hehe.

[Daryk]

How is "Hammer's Slammers" not hard science fiction?

It's definitely harder than most...

[Col Toda]

Common sense dictates that hover and bulldozer blades should not work . I am surprised that this has got the attention it has . The construction rules put all combat vehicles under the same assembly umbrella as a consequence it is certain that dozens of individual exceptions that now one thought it was needed to waste space on erratta on. 

[glitterboy2098]

As someone who does construction oversight...  I have noticed it takes heavy vehicles to move earth that are heavy and have torque.  A hovercraft I would expect to have a very hard time pushing dirt.

the hovertanks in the hammers Slammers setting run about 200 tons each. most of it being armor (which is made from an iridium alloy) and the fusion powerplant that runs the ultra-high output fans.

as scifi goes it is harder than most, but it has a lot of questionable tech assumptions, many of them related to the author's choice to basically write 'vietnam in space', using hovertanks and hovercraft to replace M-60 Patton's and M113ACAV's.

[Tai Dai Cultist]

My guess is the blade isn't for construction level "bulldozering".

Its not in any of the pictures that I can find & only a couple of them have the armored prow that it mounts too.

I'm betting is a limited use item for some of the functions mentioned above.

1.  Trigger "rod" mines early
2.  Push aside minor debris that would damage the skirts.
3.  Clearing those exploding trees mentioned above would be a combo of both the above functions.
4.  Shove a car out of the way to allow the tank column to move past.
5.  Another thing that popped into my head is angling it backwards & under the lip of the skirt just a few inches might allow it to act like a skid plate or ramp when crossing over something that wont come up easy like a tree stump.   Would be a rough ride as you are doing some "mini jumps".   At least that is what I'm picturing in my head.  Though it would probably just end up turning them over onto their side, hehe.

To add to this list I'll reiterate what I said upthread:

They'd be pretty good for clearing barbed/concertina wire fortifications meant to inhibit infantry and small vehicles.  Hovercraft have no axles/undercarriage to get fouled by the wire.

[Wolf72]

slightly off topic: but what about a hovercraft towing something? ... I know it would be limited by the motive type of the towed unit, but a wheeled or tracked trailer being pulled down a main supply route by a hover vehicle at 14 hexes at 151 kph/95 mph is kinda funny.

[righteous]

I could see it more like a cowcatcher on the front of a locomotive.  It's not going to move massive amounts of earth or grade out the land, but it pushes smaller obstructions away rather than letting them get under the skirts (or under the narrow, low traction wheels on a locomotive) to jam up the works.  Also, a cheap prow can take the minor dings without damaging the expensive vehicle - like a push bar that can be spray painted over taking the dings to keep the shiny chrome bumper (or plastic fairing) in better shape.

[glitterboy2098]

slightly off topic: but what about a hovercraft towing something? ... I know it would be limited by the motive type of the towed unit, but a wheeled or tracked trailer being pulled down a main supply route by a hover vehicle at 14 hexes at 151 kph/95 mph is kinda funny.

IRL it would be difficult and probably cause all sorts of issues for the hovercraft. in BT i don't think it is possible.

in hammer's slammers they do it all the time, and the very first story included a combatcar crew towing a cargo flatbed of supplies (including a cage of some genemodded critters) picking up a new recruit that had to have everything explained to him. said flatbed being why they were moving so slow the rebels they were fighting could hit them.

[idea weenie]

I could see it more like a cowcatcher on the front of a locomotive.  It's not going to move massive amounts of earth or grade out the land, but it pushes smaller obstructions away rather than letting them get under the skirts (or under the narrow, low traction wheels on a locomotive) to jam up the works.  Also, a cheap prow can take the minor dings without damaging the expensive vehicle - like a push bar that can be spray painted over taking the dings to keep the shiny chrome bumper (or plastic fairing) in better shape.

I'd be tempted to make it an inverse, where you have the cow catcher style, but like the prow of a boat so the hovercraft slides over the items, rather than trying to push them out of the way.  The thrust from a hovercraft is in the form of fans or jet engines, vs treads/wheels.

slightly off topic: but what about a hovercraft towing something? ... I know it would be limited by the motive type of the towed unit, but a wheeled or tracked trailer being pulled down a main supply route by a hover vehicle at 14 hexes at 151 kph/95 mph is kinda funny.

For towing, I'd require that any trailer being towed must have the same or worse traction than the towing vessel (so hover can only tow hover, wheeled can tow wheeled or hover, and tracked can tow all three).  The terrain limitation is the worse of the entire chain, i.e. a treaded vehicle towing a hovercargo platform will lose the cargo if it goes into terrain where hovercraft cannot.  Similarly, a treaded vehicle trying to tow hovercargo over water will go gurgle gurgle really quick (unless it is environmentally sealed and air-independent).  If the treaded vehicle can do it though, I predict the driver putting on music.

The nice part is that hovercargo should get a speed bonus (similar to hovercraft getting that bonus).  So a wheeled vehicle might only be able to tow 100 tons of cargo on a trailer with wheels, but might be able to handle 200 tons on a hovertrailer.  The problem is that if the wheeled vehicle has to stop suddenly, the cargo won't (unless you turn off the skirts and let it scrape to a stop).

Of course, the fun part of towing cargo with a hovercraft is where all the exhaust air is pointed directly at the cargo.  Hope all of the trailer cargo is low, dense or well-secured.

[mbear]

I could see it more like a cowcatcher on the front of a locomotive.  It's not going to move massive amounts of earth or grade out the land, but it pushes smaller obstructions away rather than letting them get under the skirts (or under the narrow, low traction wheels on a locomotive) to jam up the works.  Also, a cheap prow can take the minor dings without damaging the expensive vehicle - like a push bar that can be spray painted over taking the dings to keep the shiny chrome bumper (or plastic fairing) in better shape.

I guess I'm confused by your argument because I always thought the air was driven down through the skirt and away from the tank, so any small objects would be blown away from the fans.