Author Topic: Tail Strike (Read 635 times)

cav58d · « **on:** June 03, 2006, 08:56:01 PM »

It really looks like there is a tail strike in this photo...How is it that this jet was able to go on and fly a show after something like this...Is this commen or normal procedure for a high performance take off in the F-18?

Hawklore · « **Reply #1 on:** June 03, 2006, 09:08:08 PM »

There is still a gap..

If it did strike I doubt it'd be that bad..

eagl · « **Reply #2 on:** June 03, 2006, 09:10:57 PM »

You likely wouldn't even notice a tail strike like that on takeoff unless it caused a lot of damage. The tail feathers on the exhaust move a bit when you push on them so while they'll have to be replaced, a little scrape probably wouldn't destroy them. If it was a hard hit, the pilot might notice higher than usual temperatures or possibly the engine control unit may notice the problem and show some sort of failure.

It's not exactly common, but it does happen occasionally. F-15 pilots will occasionally scrape the tail on landing if they get too slow in the flare or if they pull the nose up too high while aerobraking. That gets expensive because in the F-15, the parts that scrape are the horizontal stab and a couple of ECM antenna covers. We don't usually do that on takeoff because we almost never do "max performance" takeoffs, but the F-15 can be overly pitch-sensitive on takeoff if the flaps are accidentally left up during takeoff, so that could be one possible scenario causing a tailstrike on takeoff - a jet configured improperly for takeoff.

My guess is that if it's on takeoff, the pilot probably rotated a few knots early, and the burner cans just scraped a bit. At that angle of attack, the wings are creating a lot of lift so there wouldn't be much weight on the burner nozzle. If you look closely, the main landing gear is fully extended and the left main tire sort of looks like it's off the ground, although it's hard to tell because of the shadowing and digital artifacting. It's supposed to be a max-performance takeoff, and that means the nozzles should be getting really close to the ground on rotation. If he's just a few knots too slow however, he might scrape a bit before lifting off.

He probably never knew about it until after landing when the crew chief gave him that sad maintainer look that says "why oh why did you do this sir because it means I have to work late?" Especially since he's #5, nobody airborn is going to be looking at his burner cans during the show so there wouldn't be any reason to call off the demo.

rabbidrabbit · « **Reply #3 on:** June 03, 2006, 09:11:34 PM »

its not taking off.. they pimped it out with phat new hydraulics.

Hawklore · « **Reply #4 on:** June 03, 2006, 09:16:31 PM »

Quote

Originally posted by eagl
You likely wouldn't even notice a tail strike like that on takeoff unless it caused a lot of damage. The tail feathers on the exhaust move a bit when you push on them so while they'll have to be replaced, a little scrape probably wouldn't destroy them. If it was a hard hit, the pilot might notice higher than usual temperatures or possibly the engine control unit may notice the problem and show some sort of failure.

It's not exactly common, but it does happen occasionally. F-15 pilots will occasionally scrape the tail on landing if they get too slow in the flare or if they pull the nose up too high while aerobraking. That gets expensive because in the F-15, the parts that scrape are the horizontal stab and a couple of ECM antenna covers. We don't usually do that on takeoff because we almost never do "max performance" takeoffs, but the F-15 can be overly pitch-sensitive on takeoff if the flaps are accidentally left up during takeoff, so that could be one possible scenario causing a tailstrike on takeoff - a jet configured improperly for takeoff.

My guess is that if it's on takeoff, the pilot probably rotated a few knots early, and the burner cans just scraped a bit. At that angle of attack, the wings are creating a lot of lift so there wouldn't be much weight on the burner nozzle. If you look closely, the main landing gear is fully extended and the left main tire sort of looks like it's off the ground, although it's hard to tell because of the shadowing and digital artifacting. It's supposed to be a max-performance takeoff, and that means the nozzles should be getting really close to the ground on rotation. If he's just a few knots too slow however, he might scrape a bit before lifting off.

He probably never knew about it until after landing when the crew chief gave him that sad maintainer look that says "why oh why did you do this sir because it means I have to work late?" Especially since he's #5, nobody airborn is going to be looking at his burner cans during the show so there wouldn't be any reason to call off the demo.

It's what i thought but didn't wanna say cause wasn't 100% positive..

Being a solo it'd only effect his speed and being off center of show center..

eagl · « **Reply #5 on:** June 03, 2006, 09:28:09 PM »

I don't think it would even noticeably affect his speed Hawk. If the nozzle was really bent up bad he might notice temperature problems, improper nozzle position readings for a particular throttle setting, and incorrect engine/throttle response, but if it was just bent a little it probably wouldn't make much of a difference at all. He'd just fix his airspeed with more or less throttle as usual, and if it's within a few percent of expected performance he'd probably dismiss it at the time because even simple air temperature and humidity variations are going to cause engine performance to go up or down a few percent. So gaining or losing a few percent of engine performance due to a bent burner can probably wouldn't be noticeable.

Hawklore · « **Reply #6 on:** June 03, 2006, 09:30:04 PM »

rgr thanks for intel.

DiabloTX · « **Reply #7 on:** June 03, 2006, 09:37:45 PM »

Also, look at the landing gear at full extension. It's obvious the plane's on it's way up and if it did scrape it is probably nothing noticable.

Debonair · « **Reply #8 on:** June 03, 2006, 10:27:35 PM »

being a blue angel, i be he lost yards of 'face'.

DiabloTX · « **Reply #9 on:** June 03, 2006, 10:31:23 PM »

Quote

Originally posted by Debonair
being a blue angel, i be he lost yards of 'face'.

You forgot your

.

Debonair · « **Reply #10 on:** June 03, 2006, 10:31:52 PM »

you stole it:O

DiabloTX · « **Reply #11 on:** June 03, 2006, 10:32:58 PM »

I did?

Holy crap.

I have no memory of the last 2 minutes.

RTR · « **Reply #12 on:** June 03, 2006, 11:23:52 PM »

I have a little over 11 years experience with the F18 as a maintainer.

Here's what I see and know.

At full power (no afterburner) the VEN's would be in thier fully closed position (max nozzle restriction). At that point the arresting hook shoe would actually be a little closer to the ground than the nozzles. (IIRC)

If you look closely at the picture, you see a small protuberance below the nozzle. That is the hook shoe, and that would be what would contact the ground. Not the VEN.

Not a big issue at all, and would have no impact whatsoever on the flight or power characteristics.

But, as was noted by eagl already the main gear looks fully unloaded and in fact it does look like he is already airborne and climbing.

Pretty good pic though!

cheers,
RTR

cav58d · « **Reply #13 on:** June 04, 2006, 12:33:27 AM »

Cool! Thanks the replies guys! --- Eagl, are you an F-15 pilot?

eagl · « **Reply #14 on:** June 04, 2006, 02:39:24 AM »

Cav - yes