• Hi Guest! Forum rules have been updated. All users please read here.

Boeing F/A-18 SuperHornet problem

rousseau

ACCESS: Secret
Joined
Aug 17, 2006
Messages
315
Reaction score
9
For starting this thread, I want to study this advanced fighter not simply post some interjections.
Now, this fighter seem to be more better than I imaged before, with superior ECM, high T/W rate, CRAET airintakes etc. But right now, I really hope to know is are there other pix which showed not prototype reveal this phenomenon as circled in pic below? Or could you please post other clear pix to show prototype of F-18E that revealed this phenomenon?
Could u tell me what this for? The three missiom you chosen I believe you can do it!

[post edited to include picture as attachment - moderator]
 

Attachments

  • bllyzevx.jpg
    bllyzevx.jpg
    10.8 KB · Views: 344

elmayerle

ACCESS: Top Secret
Senior Member
Joined
Jan 8, 2006
Messages
1,367
Reaction score
134
Er, there was no picture attached so it's a bit difficult to respond.
 

rousseau

ACCESS: Secret
Joined
Aug 17, 2006
Messages
315
Reaction score
9
This is SERECTPROJECT forum, so the thread ought ot be more difficult than other common forum, but just little bit difficult, compare with what I asked in ATS.
I do have some, just ask more.
 

Attachments

  • 20052621484971.jpg
    20052621484971.jpg
    44.2 KB · Views: 250

elmayerle

ACCESS: Top Secret
Senior Member
Joined
Jan 8, 2006
Messages
1,367
Reaction score
134
Thanks, but I didn't see anything circled. I know they had a few problems early in the flight test program, but as far as I know they've all been corrected.
 

Sentinel Chicken

American 71 Heavy, contact departure 126.47
Joined
Jan 17, 2006
Messages
590
Reaction score
60
Website
theavgeeks.com
Are you referring to what looks like a small leading edge flap just outboard of the LERX that's hinged down lower than the rest of the leading edge flaps?
 

rousseau

ACCESS: Secret
Joined
Aug 17, 2006
Messages
315
Reaction score
9
Not quite sure, the leading edge flap hinging down I only saw on prototype of F/A-18E, never saw showed on other F/A-18.
I did search alot of big pix of Super Hornet, some pivotal pix show me that flap just a part of LERX not unattached.
 

Attachments

  • Super Hornet-v.jpg
    Super Hornet-v.jpg
    184.8 KB · Views: 152

elmayerle

ACCESS: Top Secret
Senior Member
Joined
Jan 8, 2006
Messages
1,367
Reaction score
134
I think that flap may have had something to do with controlling the vortex of the LERX and they managed to find simpler and more effective approaches during the flight test phase.
 

Sundog

ACCESS: Top Secret
Senior Member
Joined
Aug 2, 2006
Messages
2,848
Reaction score
292
The biggest problem I heard of on the Super Hornet was a wing drop problem it had at high AOA. However, that was fixed to the best of my knowledge. My understanding is they used a porous material at the hinge to allow the airflow to seep through and apparently re-energize the airflow on top of the wing and either control/stabilize the separation that was occuring or prevent it.
 

Griffon

ACCESS: Restricted
Joined
Oct 15, 2006
Messages
2
Reaction score
0
the hornet you named f/a 18 e super hornet.
i found a similar aircraft known as a f/a 18 f super hornet.
 

Akaikaze

The hardest word to define is 'Normal'
Joined
Jan 14, 2007
Messages
66
Reaction score
1
Yeah, I heard about the pitch-up problem, too. Someone please explain to me how a 'brand new', computer designed fighter could could have such a flaw? The last time I read about this happening was with aircraft from the 50's. That spells trouble right there. I also heard about less than predicted range and other problems. 'Stupid Hornet' is what I call it. This is a great example of why I won't join the service. Give the Navy back it's Tomcats until they get it right, meaning, get rid of the F/A-18E/F. It'll be a whole lot cheaper and safer in the long run. :D
 

elmayerle

ACCESS: Top Secret
Senior Member
Joined
Jan 8, 2006
Messages
1,367
Reaction score
134
Ah, but CFD doesn't cover every eventuality, that's why you do flight testing. All things considered, it seems to have gone through the flight-testing shakeout fairly well. As to why the F-14 wasn't developed further, there's a lot of bureaucratic politics within the USN behind that. Email or PM me if you want the details.
 

Sentinel Chicken

American 71 Heavy, contact departure 126.47
Joined
Jan 17, 2006
Messages
590
Reaction score
60
Website
theavgeeks.com
Akaikaze said:
Give the Navy back it's Tomcats until they get it right, meaning, get rid of the F/A-18E/F. It'll be a whole lot cheaper and safer in the long run. :D
Tomcats are cheaper in the long run? The plane is an immense maintenance hog and that alone costs you in maintenance hours needed per flight hour. Even the newer F-14Ds had their share of maintenance issues. Thankfully the engines were better!
 

elmayerle

ACCESS: Top Secret
Senior Member
Joined
Jan 8, 2006
Messages
1,367
Reaction score
134
Sentinel Chicken said:
Akaikaze said:
Give the Navy back it's Tomcats until they get it right, meaning, get rid of the F/A-18E/F. It'll be a whole lot cheaper and safer in the long run. :D
Tomcats are cheaper in the long run? The plane is an immense maintenance hog and that alone costs you in maintenance hours needed per flight hour. Even the newer F-14Ds had their share of maintenance issues. Thankfully the engines were better!

I think the F-14, if it had been developed further, would have had to go through a major redesign to reduce the maintenance and reliability issues. R&M (Reliability and Maintainability) are a much, much bigger concern these days than when the F-14 was originally designed. Not as extensive, externally, as Hornet --> Super Hornet, but extensively on the internals.
 

Sundog

ACCESS: Top Secret
Senior Member
Joined
Aug 2, 2006
Messages
2,848
Reaction score
292
Not to mention, the Super Hornet is actually a totally new airframe that was just "based' off of the Hornet. To me, it was a way for the Navy to get a new fighter while convincing the politicians it was just a new "version" of the Hornet. The only thing I can't understand is why the Navy once again developed an underpowered still too short a range fighter.

At least that mistake won't be repeated on the F-35. The F-35 has an amazing fuel fraction, which I don't know if that was a fall out of the range requirement or a supercruise requirement or both. Most supercruise fighters aim for a fuel fraction of .27 or greater. I think the F-22 actually came in at .25 due to weight growth in development.
 

Schorsch

ACCESS: Restricted
Joined
Jan 17, 2006
Messages
26
Reaction score
3
elmayerle said:
I think that flap may have had something to do with controlling the vortex of the LERX and they managed to find simpler and more effective approaches during the flight test phase.

The LERX of the F/A-18E is quite huge. I think that during normal AOA operations the LERX is rather useless and undisturbed airflow on the leading edge of the wing is desired. So this "gap" is created, allowing a better flow on the wing. Otherwise a turbulence would emerge and disturb the flow on this important inner wing section. Just guessing, I am not fluent on CFD.
 

Schorsch

ACCESS: Restricted
Joined
Jan 17, 2006
Messages
26
Reaction score
3
Sundog said:
The biggest problem I heard of on the Super Hornet was a wing drop problem it had at high AOA. However, that was fixed to the best of my knowledge. My understanding is they used a porous material at the hinge to allow the airflow to seep through and apparently re-energize the airflow on top of the wing and either control/stabilize the separation that was occuring or prevent it.

They added a saw-tooth, too. These problems were solved with a variety of measures, for example new control laws for the flaps/slats.
 

F-14D

I really did change my personal text
Senior Member
Joined
Oct 4, 2007
Messages
1,780
Reaction score
138
Sentinel Chicken said:
Akaikaze said:
Give the Navy back it's Tomcats until they get it right, meaning, get rid of the F/A-18E/F. It'll be a whole lot cheaper and safer in the long run. :D
Tomcats are cheaper in the long run? The plane is an immense maintenance hog and that alone costs you in maintenance hours needed per flight hour. Even the newer F-14Ds had their share of maintenance issues. Thankfully the engines were better!

Maintenance numbers quoted for the F-14D are often misleading. As a plane approaches its retirement date, the parts supply dries up, forcing you to repair parts that before would be replaced. Fewer maintenance personnel are available or even being trained and some non-safety things are allowed to slide. At the end of its service, and as part of trying to justify its retirement in favor of the Super Hornet, you saw the figure of 50mmh/fh for a Tomcat being thrown around constantly. This number was accurate but misleading. The numbers were really high for the reasons above (and to make the Hornet look good; also F-14A maintenance figures were thrown into the mix to slew the comparison). However, if you looked at the figures for the F-14D as it was making early deployments the numbers were 17 mmh/fh and trending downward.

An F-14D with the Quickstrike enhancements built at equal production rates would cost about $2 million more per unit than an F/A18E (the delta would be less if an F/A-18F was the point of comparison). The resulting Tomcat would be both a better strike aircraft as well as a better fighter than the Super Bug. The R&D for the Super Bug also cost at least 20 times what the development work on adding all weather strike to the -14D would have cost. The Hornet E/F would cost less to maintain, but in addition to the cost of the E/F's R&D you should add in the cost of all those extra Hornet C/Ds that had to be ordered to keep the product in line "warm" (which were not included in figures detailing the cost of the E/F) until the E/F could enter production.

An excellent case can be made that the Tomcat would have been cheaper overall, but now it's a moot point. It would be impossible to bring the F-14 back.
 

flateric

ACCESS: Above Top Secret
Staff member
Top Contributor
Senior Member
Joined
Apr 2, 2006
Messages
9,086
Reaction score
983
Super Bug WT model for stores configuration tests
 

Attachments

  • FA-18E WT.jpg
    FA-18E WT.jpg
    242.2 KB · Views: 147

Blaze1

ACCESS: Restricted
Joined
May 18, 2009
Messages
19
Reaction score
0
Schorsch said:
Sundog said:
The biggest problem I heard of on the Super Hornet was a wing drop problem it had at high AOA. However, that was fixed to the best of my knowledge. My understanding is they used a porous material at the hinge to allow the airflow to seep through and apparently re-energize the airflow on top of the wing and either control/stabilize the separation that was occuring or prevent it.

They added a saw-tooth, too. These problems were solved with a variety of measures, for example new control laws for the flaps/slats.

My understanding is that the wing drop and wing rock problems were never completely resolved. The reprogramming of the control laws combined with the redesign of the wing fold covers help to mitigate the issues. The final design is apparently much improved but not perfect.
 

AeroFranz

ACCESS: Top Secret
Senior Member
Joined
May 4, 2008
Messages
2,284
Reaction score
177
Gotta find the precise information, but I remember sitting at a conference paper presentation, and someone was saying that the problem was 'cured' by limiting the angle of attack so that one wing would not drop before the other. Or maybe it was dropping the wing opposite of the wing developing the problem, so that asymmetric conditions were prevented. Either way, that hardly seems a cure to me, because you have capped the turning/lifting performance of the airplane. I'll be grateful if anyone can find more on this ;)
 

mz

ACCESS: Top Secret
Senior Member
Joined
May 28, 2007
Messages
676
Reaction score
8
I read at http://www.aerospaceweb.org/question/planes/q0099.shtml that the original (well, not the prototype which was superflexy but the as-produced) Hornet wing was quite flexible and needed a lot of washout but the super hornet wing is much stiffer.

As for the difference in twist between the earlier F-18 Hornet and newer F-18E/F Super Hornet, you are correct in pointing out that the newer model does indeed have less twist than the original. The twist on the original Hornet is slightly more than 4°, but you are mistaken in stating that the E/F has none. In actuality, the wing twist on the E/F model is about 1.5°.

Also possibly related about lerxes and vortex generators: http://www.aerospaceweb.org/question/planes/q0176.shtml
 

LowObservable

ACCESS: Top Secret
Senior Member
Joined
Oct 18, 2006
Messages
2,209
Reaction score
143
Note also that the Growler has a different "soft" leading edge notch and a fence. It was offered for the E/F but declined.
 

Similar threads

Top