Fight's On! The origins of TOPGUN and dogfights back in the day/future prospects

[yak52driver]

So the CJ's engine had a little 'sag' to it... just replaced the mounts. A least the metallurgy on your's is a bit better!

How'd you figure out the absolute load limit for the Yak?

The Russian documentation states that with the heavy spar it's good for +7/-5. Mine has that AD/mod complied with. While I've not been able to verify, I'm told the Russians use a 100% safety factor, where US certified a/c use a 50% safety factor (that is documented in the FARs). So the Pitts S2-B I used to own was certified for +6/-3, ultimate test was to +9/-4.5. There's no reason to pull more than +7/-5 in the Yak, so I'm pretty comfortable with that. During airshows +5/-2 is about all I need to pull. Even in the ACM I've done I haven't needed to pull more than +6/-0.

 

[bunk22]

Is that really the best thing to do to increase your G-tolerance? If it is, then I will integrate this into my diet so I'll be prepared.

Why? Unless you're a strike/fighter guy, really no reason to prepare. I sense future helo pilot in this one!

 

[warface]

Why? Unless you're a strike/fighter guy, really no reason to prepare. I sense future helo pilot in this one!

I plan to pull heavy G's in helos sir.

 

[HeyJoe]

What is FLE? Guessing fatigue life expectancy?
So am I correct in assuming that published symmetric and asymmetric G-limits are decided upon based on a balance of getting a long life out of the jet while at the same time allowing pilots to regularly have experience with as much of the safe operating envelope as possible? I was the engineering type in college so this stuff interests me a lot. Thanks for all the responses from those in the know.
Also, thats a great point about the broken F-15 fuselages. I've also read about a pilot who cracked the spine of his F-16 in a 9G turn at an airshow.

FLE = Fatigue Life Expended. When a new aircraft is procured, a lot of factors get dialed into the overall equation as to how many to buy to last the expected service life and it's not just the G loading that drives FLE. Typically, an airframe is determined to have x number of hours (like 4,000) of life before they have to be rebuilt regardless of G. In that calculation is an assumption that the aircraft flies only a percentage of its life with external stores. All the OPTEMPO associated with carrying weapons constantly and bringing them back accelerates the burn rate of an aircraft's FLE.

 

[yodaears]

I understand the difference is mainly a product of carrier operations. The F-18L was a program by Northrop back in the day to mod the hornet to compete with the F-16 on the export market and had comparable performance. The program was canceled but one of the mods was adapted by the Swiss AF on their hornets and that was the removal of the wing folding mechanisms. As I understand it, the Swiss regularly perform their hornets beyond our G limits.

 

[gotta_fly]

You pretty much described it. Your friends doing T-34 primary get to live with this every day (we were allowed 4.5G when I went through, nowadays if I'm not mistaken some of the T-34s* are limited to much less)... which brings up the next point, that no matter what fleet aircraft you select, if you routinely max out the limits that eventually adds up later on. Not to say you should always fly like a wuss to eke out every last bit of service life- think of naval aircraft like family hand-me-down cars in rather than rental cars.


( * Never mind the ex-military T-34Bs... whole 'nother story )

It was still +4.5 as of last year.

 

[JustAGuy]

So is there anyone out there who actually knows why newer Navy fighters are limited to 7.5 vice 9?

I understand the difference is mainly a product of carrier operations. The F-18L was a program by Northrop back in the day to mod the hornet to compete with the F-16 on the export market and had comparable performance. The program was canceled but one of the mods was adapted by the Swiss AF on their hornets and that was the removal of the wing folding mechanisms. As I understand it, the Swiss regularly perform their hornets beyond our G limits.

This is what I have heard in the past. Hornet - Wing Fold = 9G Hornet

 

[HeyJoe]

I understand the difference is mainly a product of carrier operations. The F-18L was a program by Northrop back in the day to mod the hornet to compete with the F-16 on the export market and had comparable performance. The program was canceled but one of the mods was adapted by the Swiss AF on their hornets and that was the removal of the wing folding mechanisms. As I understand it, the Swiss regularly perform their hornets beyond our G limits.

Not always, Navy operates F-16s and F-5Es that don't fly off carriers.

 

[yodaears]

Not always, Navy operates F-16s and F-5Es that don't fly off carriers.

Neither of which have wing folds.

 

[2sr2worry]

I understand the difference is mainly a product of carrier operations. The F-18L was a program by Northrop back in the day to mod the hornet to compete with the F-16 on the export market and had comparable performance. The program was canceled but one of the mods was adapted by the Swiss AF on their hornets and that was the removal of the wing folding mechanisms. As I understand it, the Swiss regularly perform their hornets beyond our G limits.

The primary structural enhancement for the Swiss Hornets was the incorporation of titanium vice aluminum wing carry-through bulkheads (Y453, Y470.5, and Y488) in the center barrel structure. This enhancement was the key enabler for rating the aircraft to 9.0G vice 7.5G.

And as others have stated MX does get a bit crabby with an overstress since there are a series of mandatory inspections--some that have to be specially prepared by NAVAIR engineering depending on circumstances. I'm still waiting for the 10.2G Super Hornet stuck in Key West to finish being inspected. :icon_tong

 

[rondebmar]

There is a great Blue Angel ride story that a Sports Illustrated reporter wrote (at least in the internet version I read) where the #7 pilot tells the reporter to eat bananas for breakfast because they taste about the same coming up as they did going down.

Article

 

[yak52driver]

Article

Thank you for finding the story, Sir. After I realized HJ's banana reference was with regards to puking, I remembered reading that story. It was an amusing read...

 

[HeyJoe]

Thank you for finding the story, Sir. After I realized HJ's banana reference was with regards to puking, I remembered reading that story. It was an amusing read...

It's a classic by a great writer...especially the part about the Milk Duds...please note it was a Tomcat ride...not a Blue Angle

 

[Flash]

I understand the difference is mainly a product of carrier operations. The F-18L was a program by Northrop back in the day to mod the hornet to compete with the F-16 on the export market and had comparable performance. The program was canceled but one of the mods was adapted by the Swiss AF on their hornets and that was the removal of the wing folding mechanisms. As I understand it, the Swiss regularly perform their hornets beyond our G limits.

They kept the folding wings as evidenced in this picture:

Easier to hide them in mountains that way .

As it was already pointed out, it is the titanium parts and software changes that allow them to take the Hornet up to 9Gs regularly. It also helps that they are specifically not equipped or have the software for ground attack, they are fighters only. Their F-5's still have the attack mission and they are running a competition now to replace them.

 

[nittany03]

I'm still waiting for the 10.2G Super Hornet stuck in Key West to finish being inspected. :icon_tong

Ouch.