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Is the Tomcat capable of a hammerhead turn/ rudder reversal


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Hi,

 

was wondering if the Tomcat ( real or simulated) can perform a hammerhead turn , i.e. going vertical or near vertical up and then rotating about the yaw axis until the nose points back down again?

 

So far my attempts have not been very successful, I might might be guessing the speed at which rudder application is added wrong or maybe I put in too little or too much rudder.

Usually I end up in some kind not-elegant flop over on the back, or a pitch hang up.

 

I’m no aerodynamics expert, I can do this relatively well in warbirds, but I’m not sure if most jet fighter aircraft and especially the F-14 are capable of this, hence the question.

 

If anybody has some pointers or knows whether it’s possible to do this maneuver, it would be great.

 

 

kind regards,

 

 Snappy 

 

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Its not something I've spent any time trying but I suspect it would need at least some cross control inputs to get the nose back down....if you take the F-14 into that kind of a nose high attitude then you've probably experienced a degree of pitch lock once the speed has bled off and you almost start coming back down in reverse rather than the nose pulling over.

 

Also at those same AOA's the F-14s rudders act more as a roll input (and should be used as such rather than lateral stick), something worth remembering in warbirds is a big chunk of the reason they fall back towards their nose is that their engine and fuel tanks etc are usually up front and impart a force to pull the nose down as soon as its even partially away from pure vertical. In the F-14 the only thing that far forward is your AWG-9, the fuel tanks and engines etc that make up a fair chunk of your weight are actually behind you.

 

 

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I honestly don't think you can do a traditional hammerhead (by inputting hard rudder near the apex of the climb). At high AOA and low speeds, rudder inputs cause the 14 to roll more than yaw.

 

I think it might be easier to yaw the 14 at the top by putting full thrust in one of the engines. 

 

Or that asymmetric power below stall speed will put you into an unrecoverable spin, one or the other. 


Edited by WelshZeCorgi
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Generally speaking, you need airflow across the rudder from the prop wash at high engine power to do a proper hammerhead at low speed.

 

The best way to do a vertical reversal in an F14 is to use it’s ability to generate high rates using its excellent pitch authority.

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Just now, Victory205 said:

Generally speaking, you need airflow across the rudder from the prop wash at high engine power to do a proper hammerhead at low speed.

 

The best way to do a vertical reversal in an F14 is to use it’s ability to generate high rates using its excellent pitch authority.

This is the difference between props and jets. I'm not sure how well prop wash is modeled in any of the sims, but at low speeds (and especially if you start falling backwards at the top of a hammerhead) the rudder can act in the opposite direction than you expect. Especially with jets where you don't have the prop pushing air to your control surfaces.

 

This is an interesting thing to test though next time I'm in DCS. Not sure I've ever attempted a hammerhead in the F-14 - I think if I ever found myself in the situation where I needed to do that in the Tomcat, then I've made some big mistakes leading up to that point.

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Generally speaking in a non-DFCS jet you would not want to make any control inputs below 100kts as that might induce a departure or flat spin. Potentially compressor stalls with the A.


Edited by Skysurfer
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Hi,

 

thank you very much for all your answers! Hadn’t expected that many replies . Lots of good input.

 

I hadn’t thought of the missing prop wash air flow that gives warbirds some remaining rudder

effectiveness at low speed as well as the different weight distribution with big heavy engine blocks in the

front of the warbirds, both things that are not there in a jet fighter.That explains why it’s difficult to do in the

F-14.

 

Bottom line: It’s more efficient to do what Victory said and use pitch authority to get the nose around back down.

 

Thanks alot again,

 

kind regards,

 

 Snappy 

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7 hours ago, Victory205 said:

Generally speaking, you need airflow across the rudder from the prop wash at high engine power to do a proper hammerhead at low speed.

 

The best way to do a vertical reversal in an F14 is to use it’s ability to generate high rates using its excellent pitch authority.


Would asymmetric thrust work as the speed bleeds down? Doubt it would be a true hammerhead in the sense of the way a prop can accomplish it, but given the thrust available it could be a very close approximation?
How tolerant are the intakes in such a high yaw scenario, the inner intake to the yaw may be okay, but could the outer handle the severely turbulent airflow coming over the nose?

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With asymmetrical thrust, yes you can (in game). But you need to symmetrize the thrust on the right time, if you symmetrize too early, the hammerhead will be slow, if too late, you will lose control for some time. This is for B model of course, not familiar with A.

 

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6 hours ago, vadupleix said:

With asymmetrical thrust, yes you can (in game). But you need to symmetrize the thrust on the right time, if you symmetrize too early, the hammerhead will be slow, if too late, you will lose control for some time. This is for B model of course, not familiar with A.

 

My next question would have been if the asymmetrical air flow would cause a compressor stall or worse. I have caused partial not fully developed stall on several situations when i introduced enough sideslip during hard aggressive ACM.

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Vadu is correct. This can be done in the F-14B in DCS. It is not realistic, and it is not ideal under any circumstance. 
 

Messing around with this, I have never encountered a compressor stall. Realistically, yes I imagine it would. To Vadu’s point, has to be timed well.

 

In DCS you can’t do this with A at all. Not possible.

 

Only time asymmetric thrust has ever been useful to me is for last second jinking on guns only dogfight servers. Hardly, something to try to perfect as a craft. 

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