Forum: F-16 Design & Construction

parrothead wrote:

Thanks Falcon-watcher! I got a good look at EVERYTHING today, too! The nice guys from the 194th Fighter Squadron of the California National Guard were nice enough to take down all the ropes around one of the F-16s Very Happy

! The pilots were there and were very nice and helpful, too. I got crawl all around and under the jet and take all the pictures I wanted Cool

!

Here's the fun part - I have lots of questions after looking at all the pictures. Here's the first question: What's this line on the radome? There are little silver dots all along its length. I've also seen these on other airplanes' radomes, but I never knew what they are. Thanks in advance!

Those metallic lines around the radome also function as a "Faraday Cage" to prevent lightning strikes from entering the radome (which is able to easily pass electrons outward, as well as inward). These are suppose to capture the lightning, and direct it to the aircraft ground, and away from the radar package. This is the same principal as why you're much safer inside your non-convertible car in a lightning storm, because even if the car is hit, the lightning shouldn't enter the inside of the car (though I'd hate to bet my life on a close call either way).

F-16.net Sponsor

I'd never thought about the effects of a lightning strike to the radar Shocked

! Not that anyone would want to fly into a thunderstorm, but just how bad would a lightning strike hurt an F-16 in flight?

That is the access door for the gun. Weapons will open it to install the holdback tool when the gun is in "cold" staus. They also due the gun lube through there. The vents are just to assist with ventilation when the gun is fired.

Rigo

We had one here at Kunsan get struck in flight this past July. the right horizontal stab had to be changed it did so much damage, plus it burned up the grounding straps that attach to the horizontal stab bellcrank nuts.

Rigo

Muchas gracias, Rigo! I always thought you had to yank panels to work on the gun for some reason. I'm glad I was wrong. Could you tell me what the "holdback tool" is? I've never heard of it before. I thought those vents might have something to do with the gun, but you know what they say about what happens when you a$$ume Wink

!

About that lightning strike, what was the nature of the damage? Was it burned by the heat? Did the skin melt? Obviously the jet landed, but did it do any damage to the actuators or the jet's electronics?

F-16 parts map.

Link to full rez. version: http://attach.high-g.net/attachments/f16partmap.jpg

parrothead wrote:

Quote:

Well for the gun system, the safing is done with the pin inserted from the outside as that door will not open and can not be opened during ground operations.

That makes sense about the safing pin for the gun, but how did they get that door open while the jet was sitting on the tarmac at the airshow? Do you mean that it just can't be opened by the pilot or ground crew while the engine's running?

I thought that connection for the ground ECS air looked like a connection for some sort of air hose. Thanks for clearing that one up for me!

Here's the next one. This panel/vent is on the top of the port side, a little ways back from the muzzle of the gun. I'm thinking it's some sort of access and vent for the gun, but I can't be sure. Thanks for all the help! I know I've been asking a lot of questions in the last few days, so please let me know if I start to get annoying Wink

!

More on the mystery vent, yep it is a door for access to the gun rotor, we can get to the safety pin through this door also. The pin is usually installed inside to out when the gun is cold. In a rush to make it hot while the jet is running you can reach down and pull it out then install it from the outside. As stated before the hold back tool is accessed here too. So is the firing lead. During ground functional checks, No spin just electrical check we can do the work through this door.

Determining problems from a lightening strike can vary. Circuit breaker accesses are opened to determine whether any shorts occurred. On most of our strikes, finding the exit is easier than finding where the strike entered. You'll talk to the pilot after the mission and he'll try to explain the best he can but finding the entry point can be tough. Opening the radome is one of the first items to do to check for integrity. CB's and then structural damage. We've had damaged radomes, rudder, and access panels from strikes.

And CCs on the ground. I had a friend hit years ago, the jet got popped on the tail at EOR while he was on the comm cord. Free electrons shot through the jet and his head to the ground. He got burned around his ears and mouth and knocked out cold. Otherwise he was fine. The jet had no damage at all. One lucky CC.

parrothead wrote:

I'd never thought about the effects of a lightning strike to the radar Shocked

! Not that anyone would want to fly into a thunderstorm, but just how bad would a lightning strike hurt an F-16 in flight?

One problem is that you really don't have to fly into a thunderstorm to be hit by a lightning strike. The bolts can travel many miles from the actual storm cell. The damage done to an F-16, or any aircraft, depends on where the hit occurs, but more importantly, where it exits. And also what the aircraft is made of. A composite aircraft can suffer severe internal damage when lightning strikes. With a metal skinned aircraft, such as the F-16, the aluminum skin conducts the majority of the electric field, keeping it all on the exterior, keeping the boxes and brains (i.e. computers, and aircrew) relatively safe from any shock. The departure burn can be pretty significant though, and is often at a trailing edge or tip (i.e. wingtip, horizontal stab, etc.). The yellow static dischargers (or static wicks as the airlines call them), are designed to provide a safe departure path for high voltage charges.

Most of the wiring inside the aircraft is protected, and some is shielded with metal braiding, to prevent the actual voltage from a lightning strike from ever entering critical wires (flight control, armament, etc), and it's also shielded to prevent the electro-magnetic pulse (EMP) caused by lightning from inducing a stray voltage or current in these critical wires.

NOAA has some great photos of sailplanes being hit by lightning over the Rockie Mountains, showing the bolt entry and exit at the same time. I?ll see if I can find that link somewhere.

DeepSpace, that's a great illustration Very Happy

, thank you!!! It answered a lot of questions I hadn't thought of yet Smile

.

EriktheF-16462, thanks for all the details!

I've gone through private pilot grond school and one thing they make sure you understand is that lightning can strike you a long ways away from the storm. I'm just curious, why is the exit point easier to find and more important? Those sailplane pics sound interesting, too.

I can't say enough about how great this community is Cool

.

parrothead, you're welcome Wink

parrothead wrote:

I'm just curious, why is the exit point easier to find and more important?

My guess is that the energy from the strike, once it finds an outlet, it all goes out that outlet. No matter how small or large. Therefore, leaving a burn mark and in one case where it exited the rudder, took a small chunk with it as well. I'm not one with a science background and am only speculating. Smile

It's just my experience that the entry point is no where as visible as the exit point.

Yep, you are welcome. That panel has had the TCTO done to change the latches. The old ones where crap and it was not uncommon to lose 1 a month. See unlike most doors that one is always being blown open. The original latches where total crap in this application. Until about 5 years ago they still where out there and even now a new panel has to have the new latches put on by Metals Tech.

Erik I remember the old latches, those damn things were so touchy when it came to adjusting them. Too tight and they would crack and break, too loose and they would shake until they cracked and broke, either way your panel either broke off or was jacked from being caught in the airflow.

Rigo

Forum: F-16 Design & Construction

Please help me identify this F-16 part