The Dreaded Reverse Thrust Discussion

[TwoBrainedCylon]

Reviving the dreaded Viper reverse thruster discussion.

After getting some knowledge beaten into my head, I finally understand the best concept for the Viper reverse thrusters would be sliding panels in the engines to redirect thrust forward. So, as a guess, just where on the viper would these panels be? The immediately most obvious place would be the visible panels, except they don't actually connect to the engines directly and seem to have valves and such where you would connect fuel lines, monitoring equipment, and the like. The actual engines seem like they are hard reinforced tubes.

Ideas on where the panels would be -- I do mean EXACTLY where they would be.

Two-Brain

[kingfish]

I would assume that when the pilot presses the IM button the turbines rotate in the opposite direction to force the airflow to move in such a way that the ship moves backwards.

[Philloz]

Originally posted by kingfish
I would assume that when the pilot presses the IM button the turbines rotate in the opposite direction to force the airflow to move in such a way that the ship moves backwards.

But there's no airflow in space ... there's no air!

I always liked the look of the Viper's design, but as a space fighter, why would the engines need those huge jet turbine intakes and wing-like fins? If they are actually reverse thrusters they would roast the cockpit and laser emplacements. When I was a kid I figured that the intakes were there because the Viper engine was some kind of rocket/air breathing hybrid (for use in atmosphere), the wings were actually heat radiators and that the scooped-out nose of the fusalage was actually the reverse thruster nozzle ...

[TwoBrainedCylon]

When I first started this trouble on the SFC board someone (I forget who but they were really smart) commented that they must be like the reverse panels at the end of the engines on a commercial jet. When the planes land, little panels open toward the ends of the engine and deflectors push the engine thrust forward, creating some breaking.

I buy that explaination as the best one. Now, I'm trying to figure out where these would logically be. On the viper, the engines appear to be huge reinforced tubes with the main engine set inside.

The intakes IMO would be used for cooling the Viper engine during atmospheric flight. In space, the coldness would keep the engines cool enough. Flying around planets, these would allow airflow to cool the engines.

Two-Brain

[Philloz]

Originally posted by TwoBrainedCylon
The intakes IMO would be used for cooling the Viper engine during atmospheric flight. In space, the coldness would keep the engines cool enough. Flying around planets, these would allow airflow to cool the engines.

Two-Brain

I wonder about that, but at the speed a Viper would fly in at atmosphere I image air friction would create a potential heat problem. The Viper should have a self-contained cooling system, because even in space temperature varies wildly. Remember that the Apollo craft would go intro a "barbecue roll" in translunar flight to prevent the ship from getting too hot or cold on one side ... solar radiation would bake you on one, the cold of space freeze you on the other. Presuming that the Viper's construction made it relatively impervious to external temperature extremes, excess heat from the engines would have to be bled off via radiators and/or some kind of internal system.

[kingfish]

I remember Apollo telling Zac to hit his reverse thrusters and breakings flaps in the pilot episode.

[Philloz]

Originally posted by kingfish
I remember Apollo telling Zac to hit his reverse thrusters and breakings flaps in the pilot episode.

This was one of the major scientific mistakes of BSG; Why would a craft need "braking flaps" in the vaccum of space? This goes along with the concept of "laser torpedoes" ... are they lasers, or torpedoes? (In use they are quite obviously high-energy laser bursts, yet they "explode" like anti-aircraft shells when they are near the target.)

Of course, it could be that, in Colonial use, "braking flaps" is a term for some other inertia-killing device that we don't understand ...

[kingfish]

This was the only believable craft that could pivot at a moments notice due to the fact there were thrusters on the front and rear of the engines.

[Philloz]

Originally posted by kingfish
This was the only believable craft that could pivot at a moments notice due to the fact there were thrusters on the front and rear of the engines.

The Starfury design is so good that, according to JMS (on his audio commentary for the B5 Season One DVD), at one point NASA contacted him for permission to use the design as the basis for an orbital utility vehicle that would be used for construction and maintainence of future space stations and manned interplanetary craft in orbit. JMS agreed with the caveat that if the vehicle was ever put into production that they had to call them Starfurys. So someday in the next twenty years or so we may be seeing them for real!

[Hito]

Are the Intakes on the front of the engines?
What is that recess in the nose for the viper?
It *could* be some kind of inertia killing thruster.

Except everytime i see them use reverse thrust on the whow the thrust is still seen coming out of the back.

[LucianG]

TwoBrainedCylon,

Sorry I haven't gotten back to you on this. I've been very busy, but I haven't forgotten it.

The original discussions were at

http://bboard.scifi.com/bboard/browse.cgi/1/5/3315/319923

and

http://bboard.scifi.com/bboard/browse.cgi/1/5/3315/319993

Since this is about 'way cool ships' from a TV show, this is, needless to say, all speculation:

The engine works on two levels. In atmospheric conditions, its a turbo jet using air to propel the ship. The air comes in the front and is propelled out the rear. In a vacuum, the turbine is disabled and the engine becomes a rocket consuming tylium fuel to produce thrust exhausting it out the rear.

The damper system proposed would allow the ship to slow, and if enough fuel was used, possibly even stop, eventually; however, in comparison to other fast moving ships (Cylon Raiders or even other Vipers), some slowing by a particular Viper on the TV screen would make it look like the ship was "going backward." In actuality, it would still be moving forward at a high rate of speed; it would actually be being passed by those ships going much faster than it.

Reversing 'turbines' as suggested is not a viable option since (1) turbines wouldn't be used in space, and (2) changing direction on rotating turbines would require slowing the rotation in one direction to an instantaneous (or longer) stop before slowly beginning (and then gaining speed) in the other direction. An instantaneous change in direction would result in destruction of the engine. An analogy: consider driving your car at 70 mph and then instantaneously throwing it in reverse. If it was even possible, the transmission repair would be quite expensive, not even considering the potential damage to the driver, and that is at a low speed in comparison to the speed at which Vipers would be traveling.

As Hito noted, even when the IM was engaged, the exhaust is still seen at the rear of the engine. The dampers proposed would direct only a portion of the thrust forward. The exhaust and a portion of the thurst would still exit the rear.

Since we didn't really see the panels you are seeking, I see three options in the vacuum of space:

1. They do not exist. The engines must be oversized to allow the reverse thrust to be 'retained' in the engine housing; however, the engine is only a few feet long, so the portion of the thrust directed forward would hit the front of the engine housing, etc. This doesn't seem reasonable.

2. The forward thrust is exhausted forward through a number of small vents we cannot see on the exterior of the engine. Again, this doesn't seem reasonable.

3. There are no vents; however, the forward exhaust is directed out through the front atmospheric intake that is not used in the vacuum of space. Since only a portion of the thrust and exhaust is redirected, the portion moving forward is not really even noticable since the Viper is moving forward as well.

Was the IM ever used in atmospheric conditions? If so, the turbine thrust and exhaust would be much smaller than that of the system used in space, so it might be redirected similar to the way jet engines do it on Earth.

On another level, the recess on the nose of the Viper could be a ram scoop, making the space system a ram jet system.

Got to go,

Lucian

[kingfish]

Originally posted by Hito
Are the Intakes on the front of the engines?
What is that recess in the nose for the viper?
It *could* be some kind of inertia killing thruster.

Except everytime i see them use reverse thrust on the whow the thrust is still seen coming out of the back.



Hito I read that the ships sensors were housed in the nose.

[Erzengel]

Anyone have any blueprints of the engines themselves?

Could the side engines be dual directional? Having thrust being able to be directed in both directions with most of the heat being thrusted out the rear when in reverse to prevent damage to the fightercraft?

[LucianG]

Could the side engines be dual directional? Having thrust being able to be directed in both directions with most of the heat being thrusted out the rear when in reverse to prevent damage to the fightercraft?

Erzengel,

In a few words, you've basically described what I was attempting to say in my item 3, above, using the damper system as the reversing system rather than having a forward facing rocket nozzle that would probably burn up the ship.

Well done.

Lucian

[Philloz]

Originally posted by kingfish
Hito I read that the ships sensors were housed in the nose.

Actually, the nose recess is where Adama sat when Apollo took him down to Caprica, since there was no room in the cockpit of what is clearly a one-seat craft (though two-seaters were the norm on G80);)

[Hito]

I always wondered where adama sat then.
I just figured there was storage space behind the pilots seat that can be converted to pasanger space in case of an emergency.

[Erzengel]

Originally posted by Philloz


Actually, the nose recess is where Adama sat when Apollo took him down to Caprica, since there was no room in the cockpit of what is clearly a one-seat craft (though two-seaters were the norm on G80);)

Huh? In the movie I saw Adama was in the cockpit behind Apollo when they flew down to caprica.

[Philloz]

Originally posted by Erzengel


Huh? In the movie I saw Adama was in the cockpit behind Apollo when they flew down to caprica.

WHEN?! The only time Adama was shown in the cockpit of a Viper was when, later in the pilot, he was sitting in one in the launch bay so he and Colonel Tigh could speak privately. The original series' full-size Viper had a single seat, no more. The two-seater variant came about in Galactica 1980, though they continued to use old special effects footage of the single-seat model.

[TwoBrainedCylon]

Lucain G,

Great stuff. Many thanks.

Everyone else, also great stuff ... never did get the Adama thing though.

Two-Brain

[Sept17th]

Originally posted by Erzengel


Huh? In the movie I saw Adama was in the cockpit behind Apollo when they flew down to caprica.


There is alot of that in TOS

[Sept17th]

Originally posted by Erzengel


Huh? In the movie I saw Adama was in the cockpit behind Apollo when they flew down to caprica.


There is alot of that in TOS

[repcisg]

It depends on which version of TOS you are watching.

[kingfish]

There may be some over at http://battlestargalacticaclub.com

[KJ]

No offence guys, but i can see why it's the dreaded reverse Viper thruster discussion. Let's lose ourselves in fantasy discussion. But not let obsession about little details when "FANTASY" is the key word!
The X-Wing's of Star Wars or Ships in most sci-fi won't do what they do in reality what they visually do onscreen. But are there to stimulate our collective imaginations by their concepts or vivid designs, movements etc. Fastasy and fact people.

Viper would look and move good in an atmostphere with it's intake and turbines and all. They are fighter crafts afterall, so maybe their design was to include manuverbilties inside a planet body thus the braking flaps wings, and atmosphere designs work fine.

Also a bigger question would be, do Vipers have a Hyperdrive or Faster than lightdrive? similar to SW X-Wings? Since we've all asked how does the Galactica travel from place to place and have sublight fighter crafts like Vipers?
The shows full of errors. In Experiment in Terra, Vipers can go to light speed in normal space? Alot of what your talking about would have to include alot of changes to the Viper's design.
Don't mind seeing an upgrade but then regardless of errors you'd have a much different design to cover sci-fi inaccurate errors of a sci-fi TV program.

Besides B5, V, Star Wars, Space: Above and Beyond and Battlestar Galactica. what other sci-fi show has come along and had dogfights in a series done right.

Half the time, what goes on regardless of the "can's and can't issues is a abandoned to have escapism and put alot of military stuff, action adventure in a space setting and let loose with the imagination.

Yes this is dreaded, it's only a TV show!

Take it easy people

:)

[Erzengel]

Originally posted by Philloz


WHEN?! The only time Adama was shown in the cockpit of a Viper was when, later in the pilot, he was sitting in one in the launch bay so he and Colonel Tigh could speak privately. The original series' full-size Viper had a single seat, no more. The two-seater variant came about in Galactica 1980, though they continued to use old special effects footage of the single-seat model.

In the version I saw adama is being helped down or is climbing down (need to rewatch that part in the next few days) the side of the viper and is clearly shown to be coming from the direction of the cockpit not the front of the viper.

One also has to take into account that the front of the viper holds the sensors and other equipment, such as the landing gear, and would be to cramped to hold a person inside.

Another note of interest is that there is no hatchs on the viper's exterior that someone can fit into. Which also makes the forward area seem unlikely that a person can ride in.

[LucianG]

No offence guys, but i can see why it's the dreaded reverse Viper thruster discussion. Let's lose ourselves in fantasy discussion. But not let obsession about little details when "FANTASY" is the key word!...

Yes this is dreaded, it's only a TV show!

KJ, I think most of us know that. From my previous post,

Since this is about 'way cool ships' from a TV show, this is, needless to say, all speculation:

Still, the reason some of us engage in this speculation is to see how we can correlate what was shown to the reality of the laws of nature. With our technology, we can't get our ideas anywhere close to the Colonials' technology, but considering that "technology" was created for a TV show by 70's era TV people, we can surely gain some insight into their ideas. However, my ultimate belief on this topic is that the folks creating the models wanted something "cool-looking" and that they weren't overly concerned about making it even try to conform to the laws of physics. In their view, "we just don't have the understanding to comprehend Colonial technology, so let's make it look good!"

[TwoBrainedCylon]

KingJason,

Actually, I was asking the question because of how an upgraded CG model would best function. I’m considering doing some animations with the Viper model that would include the reverse thrust and wanted something as canon to the original as possible while also helping to demonstrate what the reverse thrust was. This is something that was specifically identified in the script of the shows. I personally think it’s a fair issue to discuss. Admittedly, I’m a machine geek and immediately start deciphering what the components of a spaceship, land vehicle, robot model might be where the other 999 folks don’t. Most of the Star Wars and BSG equipment holds up fairly well to this, although I’ve been less impressed with the latter bulk of Trek stuff – but I digress.

Short answer is, I don't want Lucian and the others to chill. I personally enjoy their speculations.

Two-Brain

[Philloz]

Originally posted by Erzengel


In the version I saw adama is being helped down or is climbing down (need to rewatch that part in the next few days) the side of the viper and is clearly shown to be coming from the direction of the cockpit not the front of the viper.

One also has to take into account that the front of the viper holds the sensors and other equipment, such as the landing gear, and would be to cramped to hold a person inside.

Another note of interest is that there is no hatchs on the viper's exterior that someone can fit into. Which also makes the forward area seem unlikely that a person can ride in.

Uhh, I was just joking about Adama sitting in the nose recess, as indicated by my ;) emoticon ... The point being that while the filmmakers would have use believe that Adama COULD ride down in Apollo's craft, it was clear to anyone paying attention that he could not possibly fit in the tiny cockpit with his son already occupying the seat. Anyone who has been around real military fightercraft could tell you that cockpits are so cramped to begin with that a tall, strapping fellow like Lorne Greene would have difficultly stuffing himself into one even without Richard Hatch sitting in the way. As far as the Viper is concerned, the cockpit seems to be roomy enough to contain a "big-boned" fellow such as Jolly, but the ship overall is so compact that the laser generator had to be removed to make room for other modified equipment on Starbuck's recon ship CORA. Now, that's not to say that two-seater variants absolutely did not EXIST during the original series timeline, just that we were never shown any on the show. In anycase, Apollo's craft on Caprica was clearly a single-seater which could not have carried two people; this is really just a gaffe on the part of the filmmakers that disrupts the film's internal logic and makes for interesting discussion.
:colwar:

[cobrastrikelead]

Good discussion. Could not the P-39 Liightning have the radio equipment removed and be able to carry two people? I thought I had heard of General Eisenhower had one so modified so he could fly over the battlefield of Northwest France.

[LucianG]

Similar to what Two-Brain said, as an engineer, I must represent the 1 in the SECOND 1,000 fans who care about "analyzing" such stuff. When I get time, I'm going to back to my earlier postulations on how the Viper maneuvered using a three point thrust system without the benefit of maneuvering thrusters. I see this reverse thrust discussion playing an important part in that.

In anycase, Apollo's craft on Caprica was clearly a single-seater which could not have carried two people; this is really just a gaffe on the part of the filmmakers that disrupts the film's internal logic and makes for interesting discussion.

Good points, Philloz! I know that occurred right after the attack, but using a SHUTTLE would have been a lot more logical than cramming Adama into the Viper. Let's see...maybe the seat slid forward, revealling a small storage compartment where Adama, revealling his secret identity of Plastic-man to his son, sat while Apollo, secret master contortionist, flew with his feet tucked around behind his head. Reasonable? Nah, I didn't think so either.

[cobrastrikelead]

(the Lightning was the P-38 Lightning, the P-39 was the AirCobra. My mistake. Somedays I get up with a To-Duh list it seems.)

[Philloz]

Originally posted by cobrastrikelead
(the Lightning was the P-38 Lightning, the P-39 was the AirCobra. My mistake. Somedays I get up with a To-Duh list it seems.)

That's understandable, they both had a Lockheed perigree, didn't they? I don't know anything about the Eisenhower story, but it seems reasonable; you wouldn't see that happening in today's military, though I could imagine Adama might be willing to go in a stripped-down Viper, if it were physically feasible.

Of course, the most reasonble solution would be to send down Adama in a shuttle with a fighter escort, ala the landing mission in "The Gun on Ice Planet Zero." I suppose it was more dramatic the other way, though.

[LucianG]

cobrastrikelead, you are correct. The P-38 could be modified to carry two people, though not comfortably. Martin Caidin, the creator of The Six Million Dollar Man his book “Cyborg”, wrote another excellent book called “Fork-Tailed Devil: The P-38” (Ballantine Books, New York, 1971). I read it at least 20 years ago, so I couldn't remember whether their was a two seat version. It took a few minutes to find the book(with Caidin's P-47 book and my Edgar Rice Burroughs’ John Carter of Mars books that have been missing since our last move several years ago!). From pages 40 and 41:

“Both Lockheed and the Air Force came up with the idea that it might be possible to move things about in some airplanes and turn them into two-seat trainers…Between twenty and thirty P-322’s [designation of a British order of P-38 Lightnings, most of which were never delivered—the British pilots didn’t like the three planes in the first delivery] had the radio equipment and armor plating aft of the pilot removed. This exposed the main wing spar, where engineers fashioned a crude and uncomfortable ‘piggyback’ seat. The student pilot crawled and wriggled into his distressingly uncomfortable space, where inevitably he bumped his head against the cockpit roof, and prepared to watch the pilot do whatever needed doing. No dual controls meant much apprehension and wringing of hands on the part of the hapless passenger, who could do nothing but study the movements of the pilot…The AAF converted some twenty P-38F models into two seat trainers, with the piggyback arrangement, but the idea never caught on that strongly. Other P-38s, especially in the field, were modified to utilize the piggyback space for carrying passengers rather than students.”

I couldn’t find anything about General Eisenhower using the piggyback seat, but if he did, or even if it was just a myth, that very event could have served as the idea in some writer’s mind for Adama squeezing into a single seat Viper. With engines, fuel tanks, and so forth right behind the Viper's cockpit, I don't think one would be able to remove enough unessential equipment to fit a second person in there.

[cobrastrikelead]

Was there an "intake" up behind the canopy? I always thought that was where the machinery that lifted up the canopy went.

[LucianG]

For some additional information regarding maneuvering, see Michael's interview with Steve Parady at

http://www.battlestargalactica.com/gallery/models/sparady_oct99.html

This is discussion is in regard to Steve's Scarlet Viper but a similar process could be employed in the traditional Viper.