Golden canopy

[354egress]

I have never heard of anyone changing canopy transparencies (FWD OR AFT) on the F-16 other than the egress shop.

Secondly, according to Rigomortis, the transparency is 5 to 6 inches thick. This is NOT true, nor is the fact that the AFT trans is designed to shatter. If that were so, AFT seats on the F-16 B/D would have canopy breakers on them, like the A-10 Ejection seat or the F-15 ejection seats. Maybe by AFT, he means the small glass AFT of the bulkhead on the A/C models, or panel 3434 on the B/D models.

[IDCrewDawg]

Ok, So the thread is old. After reading some of it again. Yes as a Crew chief I have cleaned the inside of the main canopy and the aft canopy. Additionally, it is our job to change the Aft transparency on A/C models.

[Purplehaze]

If I recall what you folks are calling the Aft canopy is really the "fixed transparency" which is part of the airframe. That's why crew chiefs change them, and it sucks to change an old one that has baked on, sometimes it's better to break it then remove.

Purplehaze

[falcon409]

Currently, Canopies are slowly being transitioned to the 550kt type. This due to an unfortunate birdstrike incident a few years ago in which a Viper Pilot was killed when the fowl struck his 350kt transparency. It was determined (obviously) that had his aircraft been fitted with the 550kt transparency he would have survived. Consequently we have changed all our 16's to the 550kt version, The transparencies are clear but still retain the thin interior protective coating (also clear).

Anyone who could make the statement that the canopy transparency was 5"-6" thick with a straight face either doesn't know much about which he speaks or has been fed that notion by someone masquerading as an expert. 354egress has it correct, approx. 1", comprised of three layers with the primary layer a polycarbonate.

Ejecting through the transparency on the 16 or any aircraft with a like constructed transparency is not an option, the composition of the transparency won't allow that to happen. Electrically opening the canopy, using the internal manual crank handle or jettisoning with the internal jettison handle are the primary options.

Ed Wells, TSgt.
301st Egress
NAS Fort Worth

[ximeno]

5-6 inches thick no way
3 inches is right

[falcon409]

Well "ximeno", no not really. Take a tape measure or a ruler and look at what you're talking about in thickness. 3" thick polycarbonate+polyurethane+acrylic? Nope, the current 550kt transparency is a laminate comprised of a polyurethane outter about .50" thick for durability and scratch resistance, a central polycarbonate core of .75" and a thin 1/8" acrylic inner layer. As I said. . ."approx. 1" (slightly more I admit, but nowhere close to 3"). By the way, that comes from the production supervisor at Texstar (they manufacture the current F-16 transparencies) in Grand Prairie Texas whom I just spoke to yesterday on a separate matter concerning our transparencies.

[parrothead]

Falcon409, thanks for the great info and welcome aboard ! Great to have good info!

[falcon409]

No Problem. Glad to find a good outlet for info on the F-16 here and be able to contribute some of what I've learned with over 25 years in Egress.

[Pat1]

Perhaps farfetched, but yellow lenses filter out blue light and a lot of the scattering related to high frequency wavelengths. It has the effect of sharpening visual acuity, especially if the background is blue.

[Polaris]

Isn't polyurethane kind of easy to bend?

[IDCrewDawg]

Depends on thickness and the force applied.

[Purplehaze]

That's right, you want it to bend but not break, it will "flex" when the bird hits it.

[VPRGUY]

Here is another article segment from the "Semper Viper" series by the (late) J.B. Dryden, former head test pilot for LM. This one is in regards to the canopy itself...

However, I have heard some complaints about reflections in the canopy at night. You must remember that the original design of the F-16 revolved around the role of lightweight daytime air-to-air fighter. However, this quickly changed to one of multirole fighter. The possibility of the aircraft spending much more time in the arena where it might encounter birds was one change. Without fully understanding the physics involved or the tradeoffs required, a lot of attention was suddenly focused on the F-16's birdstrike problem. As a result, the canopy thickness went from three-eighths inch on the prototypes, to one-half inch on the full-scale development airplanes, and finally to three-quarters inch on the production version. Therefore, the possibility of reflections ricocheting around inside the transparency (and then into your eyes) increased markedly. It's also interesting to note that this additional canopy thickness cost you twenty-two pounds of additional weight per one-eighth inch increase.

While I have mentioned birdstrikes, let me digress for a minute on that subject. It's important to realize what we're talking about when the subject comes up for discussion.

First of all, the failure mode with a birdstrike in the F-16 is rarely one of penetration (that is, the bird does not usually come through the canopy). Instead, the impact puts a big depression in the canopy. This depression (dent, if you prefer) then progresses back along the canopy in a traveling wave, giving rise to the possibility that it (the wave) will rap you on top of the head hard enough to incapacitate you. The sweet spot required for this to happen is hardly six inches by six inches, roughly centered on the head-up display, or HUD. Anything outside this area does not create enough of a dent to hit you as this traveling wave passes by your head. I feel the odds against just such a hit are astronomical, but it was not my decision to make. So, what you now have is a canopy that will take a four-pound bird in this area at something in excess of 350 knots. This capability assumes that you are sitting at design eye. If it looks like the mission is going to require that you fly at high speeds in an area where you know there are a lot of birds, you should make note that you can get an increased safety margin simply by lowering your seat below design eye. It is also very interesting to note that the F-16 is one of only a few airplanes that has been so thoroughly scrutinized in this area.

There are several other airplanes (I won't mention any here, but you would recognize them instantly if I did) where the failure mode is one of penetration. And the airspeed that this penetration occurs is not too high (more like around 250 knots). What happens with these airplanes is that the bird hits anywhere on the windshield and travels up the windscreen, making a dent similar to one on the F-16. The difference is that, once it gets to the canopy bow, this traveling wave is severely snubbed by the canopy frame. The result is an immediate failure of the transparency, and your single-place aircraft has suddenly become occupied by another warm (but rapidly cooling) body. This is not too conducive to a much longer sortie on your part. Of course, there is always the remote possibility of taking a condor right in the chops at 600 knots in any tactical airplane, in which case all bets are off.

Source: Code One Magazine

[Purplehaze]

Very good read VPRGUY Thanks

[blk40crewdawg]

5-6 inches? Geez... how much does that thing weigh?

Rigo,

It's actually more like 1-2" thick. It weighs about 40-50 lbs.