Missing ONE horizontal stabilizer

[Citabria]

I can't stand the other thread any more about 1 hstab missing and everyone on a tangent about vert stab gone....


heres the deal. when you shoot one HORIZONTAL STABILIZER off a fighter they gain instability and maneuverability that is close or better than having intact surfaces.

losing an entire control surface of one horizontal stabilizer and one elevator is preferable to losing just one elevator in Aces High.

I have no idea if this is accurate but it seems counter intuitive that when you damage an airplane it performs better.

the only clearly visible down side to losing one hstab is the aircraft can become uncontrollable in a stall or sub stall speed vertical maneuvers.

when missing one HORIZONTAL stabilizer you gain instability in that you can pitch the nose up and down quite quickly and to a greater degree than with both stabs on.

thus reduced stability equal maneuverability. instead of being wounded when hit in the tail the wounded plane is basically undamaged for all intents and purposes of the dogfight and in some instances even more dangerous.


given that the damage system while extensive does simplify many systems of aircraft to approximate the results of battle damage this leaves the horizontal stabilizer damage results feeling likely aerodynamically accurate yet not in keeping with the methodology of battle damage decreasing combat capability.

[Greebo]

Before HTC improved the damage model the F6F would frequently lose its whole horizontal tail. Now it usually loses half its horizontal stab which is a big improvement in survivability. I find being in this state makes very little difference to the F6F's sustained turn performance, particularly once I dump flaps. USN aircraft have very good control authority which helps. There is probably a gain on instantaneous turning, pulling for a snapshot. However I have to be careful doing this as as it easier to get into a nasty spin if I push it too far.

This seems fair enough to me in terms of aerodynamics. It is the wing that generates turning performance, the tail just points the aircraft. Structurally there might be a case for saying that losing one half of the stab might increase the chances of the rear fuselage or the rest of the tail spar failing under heavy G loading.

One other thing I've noticed is how much braver some opponents become once I lose half a stab. I had a bunch of planes bnzing me last night and only realised I'd lost half my stab after a couple of them made the mistake of trying to turnfight me. 

[Noir]

thanks fester

the P51 turns better when missing ONE horizontal stabilizer, but like the F6F you have to be careful when pulling a snapshot

[earl1937]

Before HTC improved the damage model the F6F would frequently lose its whole horizontal tail. Now it usually loses half its horizontal stab which is a big improvement in survivability. I find being in this state makes very little difference to the F6F's sustained turn performance, particularly once I dump flaps. USN aircraft have very good control authority which helps. There is probably a gain on instantaneous turning, pulling for a snapshot. However I have to be careful doing this as as it easier to get into a nasty spin if I push it too far.

This seems fair enough to me in terms of aerodynamics. It is the wing that generates turning performance, the tail just points the aircraft. Structurally there might be a case for saying that losing one half of the stab might increase the chances of the rear fuselage or the rest of the tail spar failing under heavy G loading.

One other thing I've noticed is how much braver some opponents become once I lose half a stab. I had a bunch of planes bnzing me last night and only realised I'd lost half my stab after a couple of them made the mistake of trying to turnfight me. 

With or without 1/2 of your horz. stab, you are one hell of an opponent!

[Karnak]

I'd think that only having one of the horizontal stabilizers would make the remaining one very weak due to the loss of counterbalancing of forces as well as having the horizontal stabilizer's spar severed.

[USAF2010]

Waitin' for HiTech's reply 

[FLS]

I'd think that only having one of the horizontal stabilizers would make the remaining one very weak due to the loss of counterbalancing of forces as well as having the horizontal stabilizer's spar severed.

Here's an F4U tailplane being mounted. Note the lack of spar. I don't see where the remaining tailplane would have a strength issue pushing the tail down. Other aircraft construction may vary but I'd be surprised if they didn't design them to tolerate the loss of the opposite tailplane.

[Mitsu.]

Thanks Fester.

That is the thing I wanted to post.

[Bodhi]

Here's an F4U tailplane being mounted. Note the lack of spar. I don't see where the remaining tailplane would have a strength issue pushing the tail down. Other aircraft construction may vary but I'd be surprised if they didn't design them to tolerate the loss of the opposite tailplane.

That picture is misleading and makes one think the spars are not continuous when installed.

While they are indeed separate parts, the horizontals are mirror image assemblies, and in the F4u series have a rear and forward spar.  They just are not connected conventionally like most are used to.  Instead, the horizontals use a massive forged steel fitting that is mounted to the airframe to connect the rear spars.  These connections are made with special bushings that are secured by taper pins.  The forward spars are connected to the fuselage on each side by long steel pins into an aluminum fastener that is locked in with a dzus spring.  Further, the inboard edges of the horizontals are further screwed into nut plates with counter sunk #10 screws that are attached to the structural fairing that forms the gap between the fuselage and horizontal.  Beyond a shadow of a doubt, it is one of the toughest structures I have seen in an American Fighter.

In my opinion though, the complete loss of one side would be hard to accomplish without catastrophic damage to the other, as the elevators are connected completely through the assembly with the trim chain running on the sprocket halves in the center of the assembly.

[FLS]

Thanks for filling in the details Bodhi. My point was the lack of a spar going through the fuselage. I don't see how the picture is misleading when there is not a spar connecting the tailplanes. You seem to be agreeing that each tailplane has a spar bolted to the fuselage and the spars do not connect the tailplanes to each other. I assume there is sufficient bracing in the fuselage but calling that a continuous spar seems more to describe an effect than an actuality.

[Bodhi]

FLS,
The fitting in the rear does connect the rear spars together, as a continuous spar.  The forward spars are connected through the forward fittings attached to actual structure, but not as "directly" or continuous, but they do connect through an intermediary structure.

Sorry for the confusion.

[FLS]

This is what I'm looking at. It also shows the beam that connects the wings.

http://www.mediafire.com/download.php?b417jhtebj48jx2

I'm not saying you're wrong. I can accept a 3 piece spar, I'm assuming there's nothing major missing in the diagram, but not being an engineer I would describe this as 2 tailplanes bolted to a fuselage. 

[Bodhi]

FLS,
I worked on the -4 for a number of years and know it fairly well.  I am not claiming to "know-it-all", I've just spent significant time around the airframe.

The IPB pages you are showing are just rough group assembly sketches.  Let me see if I can dig up some photos, if not, I will be at my hangar on Friday and I will grab the IPB and scan the parts page for you showing what I am talking about.  The spars carry through with alternate structure in the front and with a gigantic, 10 - 15 lb forging in the rear.

[FLS]

I'll take your word for it Bodhi, I've never looked inside one.  It would be interesting to see if it's not too much trouble.

[Greebo]

My thought was that with one half of the tail missing the remaining half would under high G loads put a twisting load on the rear fuselage it wasn't designed for. I'd guess  US planes like the F4U might be less susceptible to this than European or Japanese aircraft. There is probably no meaningful data on this though so I doubt it will ever be a factor in AH's damage model.