Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
United Airline
Topic Author
Posts: 8971
Joined: Wed Jan 10, 2001 5:24 pm

Fly By Light?

Tue Jun 08, 2004 4:11 am

We all know FLY BY WIRE. What about FLY BY LIGHT? What's that? Is it any more advanced than FLY BY WIRE?

Is it being used on any aircraft?
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Fly By Light?

Tue Jun 08, 2004 4:16 am

Just like any fly-by, only with less aircraft.  Big grin

Just kidding. Fly by light is the same thing as FBW, only the signals go through fiberoptic cables rather than electrical wires.

Cheers,
Fred

I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
buckfifty
Posts: 1278
Joined: Tue Oct 16, 2001 4:05 pm

RE: Fly By Light?

Tue Jun 08, 2004 7:14 am

Fly by light can potentially provide weight savings by allowing multiplexing of signals going through one fiber optic strand, instead of a bundle of wires. Ít also will save on maintenance costs by reducing the amount of maintenance hours required, supposedly.

Not sure if it's feasible to be implemented yet, but I imagine it won't be long before commercial aircraft will be using this technology.
 
dl757md
Posts: 1483
Joined: Mon May 24, 2004 9:32 am

RE: Fly By Light?

Tue Jun 08, 2004 7:19 am

Military designs have been proposed maybe even tested, I'm not sure, where the fiberoptic filaments are actually used as reinforcing fibers in the composite structure of the AC. If you used throughout the skin almost unlimited pathways are possible resulting in retention of control in even a very badly damaged bird.
Neat s*it!

Dl757md
757 Most beautiful airliner in the sky!
 
ArmitageShanks
Posts: 3780
Joined: Tue Dec 30, 2003 5:30 am

RE: Fly By Light?

Tue Jun 08, 2004 7:33 am

Am I right by saying thousands of different data streams can be sent through a tiny wire about the size of a human hair?
 
dl757md
Posts: 1483
Joined: Mon May 24, 2004 9:32 am

RE: Fly By Light?

Tue Jun 08, 2004 7:38 am

ArmitageShanks

You are correct although it's called a filament rather than a wire.

Dl757md
757 Most beautiful airliner in the sky!
 
QantasA332
Posts: 1473
Joined: Sat Dec 13, 2003 5:47 pm

RE: Fly By Light?

Tue Jun 08, 2004 9:47 am

I know that Eurocopter for one has been testing it on its EC135s for a while...

Cheers,
QantasA332
 
United Airline
Topic Author
Posts: 8971
Joined: Wed Jan 10, 2001 5:24 pm

RE: Fly By Light?

Tue Jun 08, 2004 2:17 pm

The proposed B 747 Advanced will be FBW right?

But not the B 747-400/400ER which are by using hydralic systems.

What about the MD 11?
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: Fly By Light?

Tue Jun 08, 2004 3:55 pm

They'll both be using hydraulic systems. The difference is in how they control the hydraulic actuators.

There has been attempts at replacing the hydraulics with electrical motors but these have run into problems.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
AUAE
Posts: 292
Joined: Fri Apr 09, 2004 4:41 am

RE: Fly By Light?

Wed Jun 09, 2004 2:02 am

Fly by wire is great because the control imputs go right into a huge data bus. Fly by light will be great when the data bus for the entire airplane becomes fiber optic. That is when you will save cable weight. Until then, there is little to be gained by only having the control imputs as fiber optic.

As for MTC cost, not so sure it would save anything. You still have to make sure fiber connections stay clean and that the lines do not get broken (they are much more brittle than wire, and can't make as tight a bend).

Shawn
Air transport is just a glorified bus operation. -Michael O'Leary, Ryanair's chief executive
 
DfwRevolution
Posts: 9307
Joined: Sat Jan 09, 2010 7:31 pm

RE: Fly By Light?

Wed Jun 09, 2004 5:13 am

Not sure if it's feasible to be implemented yet, but I imagine it won't be long before commercial aircraft will be using this technology.

I've read that Boeing plans to use fiber optic cableing for not only FBW but for all avionic data busses. The Seattle PI article about the 7E7 being the most electic plane to date deatils this.

The proposed B 747 Advanced will be FBW right?

Depends, but my gut says no. For one thing, Boeing has not published any firm details about such an aircraft. It's very much a "paper" airplane.

If Boeing uses a bleedless version of the GENEX and Trent 1000 on the 747-Adv, then nearly all major systems will require redesign, including flight controls. If Boeing is going to completly replace the flight controls of the 747, I don't see why they wouldn't implement FBW. But if Boeing uses a bleeded engine of some type, I doubt it would be converted to FBW. Boeing does not want to spend a lot of development $ on the 747-Adv, so FBW might get axed.
I have a three post per topic limit. You're welcome to have the last word.
 
Leezyjet
Posts: 3544
Joined: Sun Oct 14, 2001 7:26 am

RE: Fly By Light?

Wed Jun 09, 2004 6:39 am

There is a BAC 1-11 at Brooklands that was a Fly By Light demonstrator a/c.

Don't know if there are any pics in the d.b. though.

 Smile
"She Rolls, 45 knots, 90, 135, nose comes up to 20 degrees, she's airborne - She flies, Concorde Flies"
 
QantasA332
Posts: 1473
Joined: Sat Dec 13, 2003 5:47 pm

RE: Fly By Light?

Wed Jun 09, 2004 7:27 am

Here's the BAC-111 FBL testbed; there's only one photo in the DB:


View Large View Medium
Click here for bigger photo!

Photo © Colin K. Work - AirTeamImages



Cheers,
QantasA332
 
LMP737
Posts: 6127
Joined: Wed May 08, 2002 4:06 pm

RE: Fly By Light?

Wed Jun 09, 2004 8:22 am

While the 777 uses good old fashion fly-by-wire for flight control it dies use fiber optics for other functions. The Maintenance Access Terminal (MAT) in the cockpit communicates with the AIMS cabinet in the avionics bay via fiber optics. The neat thing about fiber optics is that you don't have to worry about wires going bad. However one has to be careful routing fiber optics as not to break the them.
Never take financial advice from co-workers.
 
nudelhirsch
Posts: 1371
Joined: Sun Oct 12, 2003 6:20 am

RE: Fly By Light?

Wed Jun 09, 2004 5:29 pm

Ho about fly by WiFi...lol

No, I seriously have a question:
I know from computer networking, that fiberoptic cables need looong turns around corners, and they break if they are bent too much. Is it realistic on an airplane, especially in the crowded structure segments and moving parts to install them? Would a light-current-converter be installed and normal cables be used?
Also, fiberoptic cables are capable of far more data speed, can there result a problem on an AC when both technologies are mixed?

Putana da Seatbeltz!
 
Klaus
Posts: 21642
Joined: Wed Jul 11, 2001 7:41 am

RE: Fly By Light?

Wed Jun 09, 2004 7:50 pm

I can´t see a major mechanical problem in the installation of fiber cables... A little planning and a few changes in the routing should be sufficient.

Data speed is not a problem; Digital multiplexed signals will connect routers or interface nodes throughout the aircraft and the data sub-streams relevant at that point can be extracted or injected as needed; Data stream speed conversion is based on established standard techniques and shouldn´t be a problem.

Using single fiber cables instead of the old copper wire bundles could also open the opportunity to increase redundancy by adding more independent signal paths for increased safety at still lower weight.

Improved immunity against electromagnetic interference is just another added bonus.

Theoretically, you only need one electric power bus and one single fiber-optical data connection to control everything. Having multiple copies of those would only be for redundancy. (Multiplexed data communication is already used with copper wires, so it´s only a relatively minor step to replace them with optical fibers.)
 
haraelm
Posts: 10
Joined: Fri Jun 11, 2004 6:34 am

RE: Fly By Light?

Sat Jun 12, 2004 1:07 pm

Back in the 1970s an A-7 aircraft was fitted with fiber optic cables weighing about 2 kg to replace a 40 kg copper-wire harness. Amusingly, a heavy metal weight had to be installed to re-balance the aircraft.

The technology, components and fiber optic "wires" are all available today to be used in FBL (Fly-By-Light) systems. In particular, the low-loss, broadband, perfluorinated optical fiber which was developed by professor Yasuhiro KOIKE at Keio University in Japan more than 2 years ago, has made FBL practical.

The fiber resembles nylon fishing line and is almost as strong. Transmission distances of more than 1 km carrying signals at 1 Gb/s can be supported.

Cabling an aircraft will be no problem because the fiber can be made to have a diameter of about 1 mm and sheathed with non-flammable plastic. The large diameter makes splicing and connectorization an easy task. Also, there are no fine glass-fiber ends that might be left behind to cause health problems.

Existing components such as photonic transmission/receiver modules and connectors can all be used with a little or no modification. In fact, "old", well developed technology can be used.

The system design engineer will have a wide range of network options to consider. A data-bus type network using 1 GHz/100 MHz/10 MHz Ethernet technology might be considered although the star-network of the centralized switching configuration might offer a more diverse distribution of transmission paths. In either case, ample redundancy can be built in because of the large volume and weight of copper-wires that the plastic fiber optic cable will be replacing.

Happy FBL!
 
Jetmek319
Posts: 193
Joined: Fri Sep 26, 2003 8:02 am

RE: Fly By Light?

Thu Jun 17, 2004 5:45 am

I've heard rumors going around here that a couple of Eurofighters and a Tornado are being used as testbeds for FBL systems. Will check around and see what I can dredge up!
Never, ever moon a werewolf !!
 
delta-flyer
Posts: 2633
Joined: Mon Jul 30, 2001 9:47 am

RE: Fly By Light?

Thu Jun 17, 2004 12:41 pm

MacAir has test flown an F-15 demonstrator in the early 90's called FLASH - Fly By Light .... something (can't remember)

It also used a number of EHA's for flight controls (Electro-Hydrostatic Actuators)

Pete  Smile
"In God we trust, everyone else bring data"
 
paulc
Posts: 1440
Joined: Mon Mar 05, 2001 10:42 pm

RE: Fly By Light?

Tue Jun 29, 2004 4:24 pm

The BAc1-11 at Brooklands (pictured earlier) only had 1 set of control surfaces operating under 'fly-by-light' with normal control systems on the rest.
English First, British Second, european Never!

Who is online

Users browsing this forum: No registered users and 12 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos