Control surfaces used by Trav spacecraft in atmosphere

[F33D]

http://www.wisegeek.com/what-is-a-plasma-actuator.htm

No moving parts (surfaces) needed.

A plasma actuator is a form of advanced servomechanism being developed primarily for aircraft control surfaces as of 2011. The actuator system uses the flow of plasma, which is a highly-ionized gas, to create an easily-moldable surface that can function as typical ailerons or flaps do on aircraft, creating drag and lift at key points in flight maneuvers such as takeoffs and landings. The effect is created by high-voltage alternating electrical current and uses normal atmospheric air to create the plasma gas itself.

The Air Force Research Laboratory (AFRL) in the US has been researching the plasma actuator since at least 2006 for use in supersonic aircraft designs. Such devices are believed to offer greater reliability than traditional mechanical flaps with the likelihood of reduced weight for the body of the vehicle, which would offer it greater maneuverability and long-range capabilities. In research at AFRL, the plasma actuator has been tested in a wind tunnel at speeds up to five times that of the speed of sound.

 

[silburnl]

Interesting - thanks for the link. So this would be an engineering solution for conventional TL8-9 airfoil aircraft designs I guess.

I'm not sure how useful it would be once gravitic technologies come along though - why use control surfaces and airflow to create lift and drag for vehicles conducting atmospheric ops when the pilot can just retune their grav plates and generate the required forces directly?

Regards
Luke

 

[F33D]

why use control surfaces and airflow to create lift and drag for vehicles conducting atmospheric ops when the pilot can just retune their grav plates and generate the required forces directly?

Regards
Luke

Because according to the rules, grav just allows for, what is basically a controlled crash landing. I of course ignore that insane rule. But, I thought I'd give an alternative...

 

[Captain Jonah]

Well gravatic drives may enable you to fly but a lot of things want to have better performance than a flying brick.

Shuttles, fighters, high performance personal craft etc would all want more mobility and response than that given by an up or down forward or backward grav drive.

Isn't this a follow on from the plasma shield idea for leading wing edges and hull/nose areas to reduce friction for ultra high speed flight. Not heard it mentioned for a while but the plan was for plasma fields over the leading areas of re-entry craft or high mach craft to remove the need for heavy/complex/expensive heat shielding.

 

[Rikki Tikki Traveller]

An interesting option.

I have always used the concept of Shape Memory Alloys. These are metals that when heated or subjected to an electrical charge will change their shape in a known and predictable way. When the current is removed or the object cools, it will return to its original shape.

We have this technology already, although it hasn't been widely used up to now. A friend of mine got his PhD working with this stuff.

When used as a control surface, you have no moving parts within the surface itself. Under MGT, I have used this definition to explain the "Aerofins".

 

[hdan]

I have always used the concept of Shape Memory Alloys. These are metals that when heated or subjected to an electrical charge will change their shape in a known and predictable way. When the current is removed or the object cools, it will return to its original shape.

It always seemed to me that air friction and atmosphere temperature would render such control surfaces tricky if not useless, but I'm not a material scientist.

 

[F33D]

I have always used the concept of Shape Memory Alloys. These are metals that when heated or subjected to an electrical charge will change their shape in a known and predictable way. When the current is removed or the object cools, it will return to its original shape.

It always seemed to me that air friction and atmosphere temperature would render such control surfaces tricky if not useless, but I'm not a material scientist.

At high speeds they would be useless due to force of air flow.

 

[Rikki Tikki Traveller]

I have heard both of those arguments before, and they may be valid. However, my PhD friend who was studying them was working towards an application on the National Aerospace Plane (NASP) which was a Mach 5.0+ design, so he at least thought the issues could be overcome. That is part of what his PhD was about.

He used the version that regulated the shape via electrical flow rather than heat for precisely the issues mentioned above.

It has been several years, and maybe he didn't solve all the issues. But that is what I know.

 

[F33D]

He used the version that regulated the shape via electrical flow rather than heat for precisely the issues mentioned above.

It has been several years, and maybe he didn't solve all the issues. But that is what I know.

Yes. They didn't end up using those control surfaces on that plane. Probably because of the thinness of the material that would deform under electrical current. The plasma approach is still under development though.

 

[Jak Nazryth]

F33D, is this thread an alternative to aerofins or just general discussion on how Traveller ships maneuver? Because IMHO the 5% aerofin has got to be one of the biggest wastes of money and tonnage you can spend on a spacecraft. Since 99.999999999% of space combat happens, go figure… in space, the +2 maneuver bonus you get for the aerofins are simply not worth the money and space you can use for money making space, like cargo and staterooms. Since a space combat round is 6 minutes, most combat ships with a decent thrust rating will be out of a typical atmosphere in a couple of rounds anyway (sorry, at work so I’m not looking at the charts), but a thrust rating of 4G should be well out of the atmosphere in 12 minutes… right????
The only thing I would consider is small craft, like a fighter or assault craft that man in fact encounter lots of combat while landing and/or air cover. At least 5% of a 10-20 ton ship isn’t such a loss.
BTW, in HIGH GUARD, the paragraph describing aerofins state 5% and the chart on the following page states 10%. Any idea of which is correct? I’m assuming the 10% is a typo.

 

[F33D]

F33D, is this thread an alternative to aerofins or just general discussion on how Traveller ships maneuver? Because IMHO the 5% aerofin has got to be one of the biggest wastes of money and tonnage you can spend on a spacecraft.

I propose that this is how standard & airframe ships would maneuver. The 5% waste should only apply to primitive craft like the space shuttle... IMO

 

[Greylond]

F33D, is this thread an alternative to aerofins or just general discussion on how Traveller ships maneuver? Because IMHO the 5% aerofin has got to be one of the biggest wastes of money and tonnage you can spend on a spacecraft.

Well, there's the -2 DM for trying to Land in an unstreamlined ship. It's kinda like Insurance, you think it's a waste of money, until you actually need it...

Now, if you are only doing merchant runs and always landing at a good starport, then you'll probably be ok with the -2 DM. If you go on an adventure and try to land or do any important maneuvering/combat in an atmosphere, then that -2 DM can be painful. I've seen enough adventures where you have to land without a spaceport or do combat maneuvers in atmo so that any ship I have as a player will be Streamlined...

 

[F33D]

Well, there's the -2 DM for trying to Land in an unstreamlined ship. It's kinda like Insurance, you think it's a waste of money, until you actually need it...

That was an incorrect rule added after the rule's author finished. The editor didn't understand how ships operated. You can ignore that and the whole, needs elaborate launch set up to lift off thing.

 

[Greylond]

Has that been covered by Errata?

 

[F33D]

Has that been covered by Errata?

No. There is an errata backlog of a couple years at least.

 

[Greylond]

So, and I'm serious, how do you know it's an incorrect rule?

 

[F33D]

So, and I'm serious, how do you know it's an incorrect rule?

The author of that part of the Core Rule Book said so.

 

[Greylond]

Where? Somewhere here?

 

[F33D]

Where? Somewhere here?

Over on Marc's website forums.

 

[Greylond]

Got a link to that? The only thing I found over at travellerrpg.com is where the author agrees that non-streamlined hulls are "very ungainly and ponderous, capable of only non-lift generating powered flight." I don't see anything that justifies taking away the -2 DM for landing.