Dom Question

[Chavelo]

In the Dom's profile it says it has 58,200kg of thrust. Is there any indication of how much of that is devoted to simply hovering?

And does anyone know how much of a help in hovering is the skirted armor? I know it helps. But is there an estimated figure. Perhaps someone who knows physics can help. >_>;

Any help would be appreciated.

[Hyakushiki]

The skirt helps to direct thrust downward for lift.

[Chavelo]

That I understand. It's by how much I'm curious about.

[toysdream]

Actually, the skirt doesn't really do much when it comes to hovering. The jet engines in the feet provide most of the hover functions; the published explanations say that the conventional thrusters in the back and skirt are used mainly for forward motion.

According to the specs for Gundam 0083's Dom Tropen, the foot thrusters contribute about 7,000 kg of thrust apiece, so together they'd account for about a quarter of the Dom's total thrust. (Implausibly small, but then the current specs for One Year War mobile suits are largely rubbish.)

-- Mark

[Chavelo]

That's good to know. Thank you. Though I guess this brings up another question.

Since the Dom's figure aren't correct, which falls in line with some complaints of missing thruster figures, what would be a reasonable amount of thrust to achieve hovering? Is it just as much thrust equal to the full weight?

[Tafumi]

As far as I would figure, enough thrust required to keep the Dom's weight off the ground is all that is required. Too much and the Dom starts to lift off. Basic science at it's best.

Unfortunately, I'm no math genius. So the calculations for that (in reference to required thrust to weight values - while a google search away) is something I fail at.

[toysdream]

Since the Dom's figure aren't correct, which falls in line with some complaints of missing thruster figures, what would be a reasonable amount of thrust to achieve hovering? Is it just as much thrust equal to the full weight?

That would depend on the exact mechanism by which the Dom hovers. I dimly recall a thread on this subject a year or two ago, and I think people mentioned possibilities like these...

* Ground-effect hovercraft. This doesn't require much thrust, but you need something to hold your air cushion in place, like the hovercraft skirt seen on the Dom Tropen's feet. Perhaps we could think of the Tropen as a more realistic retcon of the Dom design.

* Airfoil design. Perhaps the Dom is designed in such a way that its body shape provides additional lift, although it doesn't really look like it.

* Pure thrust. If the Dom can direct exactly one gee of thrust straight up, then it can effectively levitate above the ground. This is how it was spec'd in Gundam Century, where all the mobile suits had a great deal more thrust.

There are probably other possibilities too, and perhaps somebody can throw in some more suggestions. But of these, the Tropen-style hovercraft is probably the most plausible.

-- Mark

[v_zubko]

What about a dynamic air cushion?

[WhiteWingDemon]

Well I'm no expert on physics but in order for the Dom to hover, wouldn't it need its weight * 9.8 in Force from the thrusters in its feet to hover. Therefore replacing the normal force from the ground with that of a cushion of air? Of course it is probably much more complicated the F=mg.

[domtropen]

Also wondering can hovering be achieved without extremely high temperature from thruster? To have Dom burning and evaporating everything under its feet doesn't sound too good.

[Recon 5]

Dom exhaust- in fact, ALL MS exhaust- would logically be extremely hot. However, MS armor is more heat resistant than modern physics would assume it to be.

[Chavelo]

I personally would go with hovercraft air cushion theory. But considering how much fuel a Dom houses, I wouldn't be surprised if it was straight forward downward thrust. Thanks Mark, much appreciated

Though speaking of heat. With the Dom using thermal heat for it's thrusters, does this mean it wouldn't need much in the way of a radiator?

Though I recall reading something about the Harrier's hovering performance being reduced based in how cold or hot it was, and how it had to use water to cool it down. Not sure about that, not much of a fighter buff.

[Gadget]

Though I recall reading something about the Harrier's hovering performance being reduced based in how cold or hot it was, and how it had to use water to cool it down. Not sure about that, not much of a fighter buff.

I think that would be the Soviet's Yakovlev Yak-141. It has a 90 degreee thrust vector. Think of the thrust vector in the VF-1, but pointing 90 degree down. However, for the thrust vector to work, the afterburner has to be activate. This will damage the runway, or the airfield.

The Harrier has no afterburner.

[FEMC_Mirage_Corp]

I personally would go with hovercraft air cushion theory. But considering how much fuel a Dom houses, I wouldn't be surprised if it was straight forward downward thrust. Thanks Mark, much appreciated

Though speaking of heat. With the Dom using thermal heat for it's thrusters, does this mean it wouldn't need much in the way of a radiator?

Though I recall reading something about the Harrier's hovering performance being reduced based in how cold or hot it was, and how it had to use water to cool it down. Not sure about that, not much of a fighter buff.

Ambient temperature affects both aircraft and helicopter performance because hot air is less dense than cold air (with gases the molecules are moving about more if their temp is higher and thus occupy more space). So if you are operating where the temp is higher you are effectively working in "thinner" air, which means it's more difficult to create the high/low pressure differential that is the basis for how wings and rotors work. I've not heard of them using water to cool off Harriers and am unsure exactly how that would help their performance.

However hot exhaust gases are yes, perfectly capable of damaging things and this is an issue with pretty much all jet engine based VTOL aircraft, though to varying degrees.

It doesn't actually require much of a cushion to create an air bubble/hovercraft sort of effect. P-38 Lightings in WWII used a trick that Charles Lindberg taught them, which he had used in his cross Atlantic flight IIRC. If you fly very close to the surface of the water it creates an air bubble that increases the lift you get, letting you throttle back on the engines and increasing your fuel efficiency, significantly increasing your range. The Russians actually built a couple of prototype aircraft ("The Caspian Sea Monster or Ekranoplane (SP)) that were designed to exploit this effect to let them move some substantial numbers of troops and armor.

Not entirely sure how a DOM would benefit from this sort of effect, but it's still kinda relevant. Using hot gases for thrust wouldn't necessarily reduce cooling needs though. A lot comes down to how the system is implemented which given the spotty basis in reality that most gundam stuff has, is unknowable.

[Gelgoog Jager]

Since we are talking about the Dom, I have some questions regarding the scattering beam gun:

I was watching the TV episodes of MSG, where the Black Tri-Stars attack. When they use the Scattering Beam Gun, they actually seem to fire a beam instead of just creating a flash. I suppose this was changed when the Trilogy was made, so:

Were Doms originally meant to use the scattering beam guns as chest mountd beam cannons?

After the change, is the scattering beam gun capable of dealing any damage, or it is only for making flashes now?

Is the MS-10 Dowadge using a scattering beam gun as well, or a chest-mounted beam cannon?

[Hyakushiki]

The scattering beam gun on the Dom was an early attempt by Zeon to mount beam weapons on their Mobile Suits but it was too weak to do serious damage. I'd imagine it was meant to be chest mounted from the beginning so it can be close to it's power source.

[Jynx]

IIRC, like Hyakushiki and others have mentioned, the scattering beam beam gun was originally designed to be an offensive weapon. Unfortunately the Dom's generator couldn't support the power requirements, so instead of removing the gear from the MS design entirely, they just attached a refraction lense to scatter the beam. This enabled a wide dispersion of light that was intended to blind or distract an enemy.

I think it's entirely possible that a Dom could fire a beam from it's chest if the refraction lense was removed, it would just be underpowered.