A-4 Skyhawk slats questions

[Supertom]

Hi everyone,

Would someone tell me if the slats on the A-4 always deployed when the aircraft is on the ground? I might have erm, accidentally glued them shut.

[okthree]

Yes the slats should be open on the ground. They are spring loaded and deploy when the air load get below a certain point. The only Skyhawks that had the slats fixed were the Blue Angels.

[Supertom]

Crap!

Well, I hope Fujimi has a good customer service program because I can't remove them without damaging them.

[Mumbles]

Blue Angels excepted, Skyhawk slats at rest are open. However, it isn't/hasn't been unknown for some operators to lock them up when the aircraft is parked. It is unusual, but not unknown either. There are pics around of parked A-4's with the slats up, like this RNZAF example:

http://motty.hobbyvista.com/Beasts-Pages/S...-KIWI-A4-15.jpg

[GreyGhost]

I'm not positive about this but I think some Adversary Scooters had the slats locked up too ...

Gregg

[Andre]

I'm not positive about this but I think some Adversary Scooters had the slats locked up too ...

I must say that to me this does sound a bit unlikely at first sight - the slats were, after all, wired shut on the Blue Angels' A-4's to prevent them from deploying asymmetrically while flying in very close formation, but as this modification impairs manoeuvrability I can't think of any reason why you would want this on an Adversary bird.

Then again, stranger things have happened...

Cheers,

Andre

[Mumbles]

I must say that to me this does sound a bit unlikely at first sight - the slats were, after all, wired shut on the Blue Angels' A-4's to prevent them from deploying asymmetrically while flying in very close formation, but as this modification impairs manoeuvrability I can't think of any reason why you would want this on an Adversary bird.

Then again, stranger things have happened...

Cheers,

Andre

Funny, I was going to say the same thing as GreyGhost about having a feeling some adversary scooters had the slats wired/locked shut. Interesting to note that while the Blue Angels took that option, at least two other Skyhawk close formation / aerobatic teams didn't, and operated the aircraft in the normal configuration (Singaporean Black Knights with A-4SU's, and New Zealand Kiwi Red with A-4K's).

Also in response to an earlier post the slats aren't spring loaded or actuated in any way. They are mounted freely on runners and deploy or retract solely due to airflow or G-loading.

[Andre]

Also in response to an earlier post the slats aren't spring loaded or actuated in any way. They are mounted freely on runners and deploy or retract solely due to airflow or G-loading.

It is especially the, eh, 'free spirited nature' of the slat configuration on the Skyhawk that lead to the BA mod - you *really* don't want any uncontrollable actuation or retraction of the slats, let alone asymmetrical actuation or retraction, when flying multiple jets a meter apart at high speed...

Since close formation flying isn't exactly a requirement for Adversaries, which would instead require all the manoeuvrability available, the mod would appear illogical for them.

The most likely reason Singaporean and New Zealand demo Scooters retained their slats would seem to me that those nations still used the A-4 in a war role at the time, in contrast to the US Navy which began equipping the Blue Angels with A-4F's (with guns, armor plating and avionics package deleted, so it would take a lot of effort to make them combat capable again) in 1974 and phased out the last operational A-4F's in 1975 (with a few Naval Reserve units soldiering on until 1978).

Edit: just after I posted this, I suddenly recalled reading somewhere that, after their Blue Angels service, some of their modded A-4F's were reassigned to Adversary squadrons... so there might be something to it after all!

Cheers,

Andre

Edited April 19, 2010 by Andre

[Jennings]

I hate to beat a dead horse to death again, but just like the F-86 and F-100, the slats on the A-4 are gravity operated. They're not spring loaded, they fall down by gravity. Air flow pushes them closed as airspeed increases, at which point their job is done, as the lift they generate is no longer needed. Conversely, as airspeed decreases when the a/c is preparing to land, the reduced air flow over them allows them to fall down and begin generating the extra lift that is needed at low speed. This, just like trailing edge Fowler type flaps (which the A-4 doesn't have, btw), increases the chord of the wing, allowing a slower approach speed (a huge safety factor when trapping aboard a ship). The A-4 has simple split flaps on the trailing edges.

Slats are not 'pinned' closed when the a/c is on the ground. I've verified this with a couple of former F-86/F-100 crew chiefs, and it makes 100% sense from an operational safety point of view. If you consider Mr. Murphy and his law, anything that can go wrong will. If the slats were (for some reason???) pinned closed on the ground, there would be every opportunity for one of them to remain pinned and the other not when the a/c took off. That would be in immediate death sentence for the pilot, as you'd end up with a massive asymmetrical lift condition. I can state with 100% certainty that the F-86 and F-100 had no such provision, and I'm certain the A-4 didn't either, simply because there would be no operational reason for it. You do see occasional photos of F-86s parked with slats closed. The ground crews would sometimes push them closed (not 'pin them closed') to keep from banging their noggins on the corners of them when scooting around under the wings. However, as soon as the a/c started moving, they would naturally fall open.

The reason some a/c had the slats permanently bolted closed was to prevent any possibility of asymmetrical deployment during maneuvers at low altitude. In the case of the Blue Angels the reason for that is self-evident. For the adversaries, the reason is probably the same - those guys did some hairy stuff down low. The A-4 was not designed to kink & jink at airshows. It was designed to deliver air to ground ordnance. For its designed mission, slat operation by airflow/gravity is perfectly adequate and safe. For the additional tasks asked of the A-4 later in its life, the increase in approach speed was a very worthwhile tradeoff for the increased safety of not having to worry about asymmetrical lift should one slat deploy and the other not.

So, except for those few a/c which had their slats permanently bolted closed (the BA's single seaters and apparently a few Top Gun a/c), all A-4s should be portrayed with the slats deployed when the a/c is parked.

J

Edited April 19, 2010 by Jennings

[Joe Hegedus]

Generally accurate info clipped out for brevity.

So, except for those few a/c which had their slats permanently bolted closed (the BA's single seaters and apparently a few Top Gun a/c), all A-4s should be portrayed with the slats deployed when the a/c is parked.

J

While the BA and some other A-4s had the slats permanantly closed, it is still possible (albeit rare) for a parked A-4 to have the slats retracted. Somewhere in my files I've got a pair of photos of one particular A-4, one with the slats out and one with the slats in while parked. Both photos are of the same airplane in the same scheme, so make of it what you will.

[Finn]

Some pics found on the net of A-4s with slats up:

at the moment of launch:

http://sciencedude.freedomblogging.com/fil.../07/skyhawk.jpg

on display:

http://www.clubhyper.com/reference/images/skyhawkrsaf_4.jpg

slats up on the ground:

http://media.airspacemag.com/images/hotrod.jpg

with the slats pinned:

http://www.aircraftresourcecenter.com/AWA1...of/Pict0156.JPG

Jari

[spejic]

And you could always build your model in flight.

[Andrew D. the Jolly Rogers guy]

Actually folks, if you look at photos of NFWS's (Topgun's) original A-4's, back before they adopted their famous logo on the tail, when they had black two-digit numbers on the tail, you will see they had their slats locked in the up/closed position. Can't remember for the life of me why they would want to do that, but they did. I read it somewhere in an account of NFWS's original instructors, and that one detail jumped out at me, so I scrambled to all my photos, including the Colors & Markings issue to confirm it. Boy, was I surprised!

[Jennings]

The only reason they would permanently lock them up is, as noted, to prevent the possibility of asymmetrical deployment during low altitude maneuvering. Believe me, that's something that will ruin your entire day, assuming they're not scraping you up with a whisk broom and a dust pan. There would be no other reason to bolt them closed.

J

Edited April 19, 2010 by Jennings

[Mumbles]

From the same source as my earlier link, a couple of Kiwi A-4's on the ground with the slats up circa 1970's-early 80's.

http://motty.hobbyvista.com/Beasts-Pages/S...-KIWI-A4-16.jpg

Just to repeat, it isn't especially common, but not unheard of either (for whatever reasons). These are the only pics I have seen of RNZAF sqawks configured like this (aside from those of the fleet as it is currently configured in storage-slats up, but also covered in latex :D ).

I think the OP could reasonably get away with leaving the model as it is (albeit learning the lesson for next time :lol: ), I don't see it as a huge accuracy fail, especially as many A-4 kits have the slats moulded shut anyway. FWIW I've built 7 Skyhawks so far, 5 with slats down and 2 with them up.

Edited April 19, 2010 by Mumbles

[Collin]

When I was flying with VFC-12 our A-4F/TA-4F birds did not have their slats wired/bolted shut. Don't believe VF-43 had their slats done that way either except for the ex-Blues A-4F they had on their line at the time (they left those slats bolted shut).

A asymetric deployment of the slats at or near stalling speed meant a nasty depature if you weren't careful. We always did a G-warm up before the first engagement and took it/pulled g to the airspeed bleed off point where the slats would deploy just to make sure.

Slats deployed was also a good way to tell the energy state of an A-4 if you were fighting one, meaning if you saw them deployed...they were slow with not a lot of g to pull.

Cheers

ATIS

[Rick in Maine]

To help ole SuperTom with his original inquiry...yes, it's possible for the slats to be up while an A-4 is on the ground.

If it was my model and everything else was rockin' along just fine, I'd leave 'em alone. There are references here to support your choice...up or down.

Rick in Maine

[ventura_kelley]

A-4C slats up:

http://data3.primeportal.net/hangar/howard...17_08_of_44.jpg

Israeli A-4E Parked slats up.

http://www.primeportal.net/hangar/isaac_gershman/a-4e/

A-4F parked slats up

http://data3.primeportal.net/hangar/bill_s...18_11_of_32.jpg

A-4M slats up.

http://data3.primeportal.net/hangar/bill_s...64_03_of_44.jpg

A-4N slats up, and it looks like there's actually a pin for them too.

http://data3.primeportal.net/hangar/isaac_..._001_of_108.jpg

And finally, an A-4B VERY low and VERY slow with the slats up:

http://www.primeportal.net/hangar/luc_coli...yhawk/index.php

Actually, I'm just messing with everyone on that last one.

But it looks like you can build a Skyhawk with the slats either up or down and be right.

[Steve jahn]

I have read all the responses to this subject and decided to look ay all my photos and books of Skyhawks. The only thing consistant was that there was no consistancy on what A-4 had the slats up and what plane had the slats down while it was sitting the ground. All A-4 models appear to be in both configurations. As far as the same squadron, some were up and some were down.If they were set to open on the ground then they should all be down except for BA and other specific aircraft for what ever reason. I remember working trans alert back in the eighties but I can't remember any safety pin or device that kept them up, so what exactly kept the slats up while on the ground then?

Steve

Edited April 20, 2010 by Steve jahn

[a4s4eva]

Jennings is correct.

Slats down is the normal position on the ground for most aircraft except the BA jets (and maybe some Adversary ones, I don't know for sure).

The Slats on the Kiwi A-4K are held up by a strap. In the 5 yrs I worked on them they were rarely up. Only if the airframe guys were doing some maintenance.

Not sure why in the photo above they are strapped back, but that hot was taken in the mid 1980's before my time. All the prime portal photos are of museum/storage aircraft so can’t be considered reflective of operational aircraft.

[Superheat]

Gents,

For the record I have 650 hrs in the A-4, most of it in the T as an IP in VT-21, but some in the A-4L as well on the CAG-20 staff. A lot of my A-4 time is ACM since I came to the Training Command out of the fighter community and was the Fighter Training Officer on the CAG-20 staff. More on that later.

The slats were, as has been stated, controlled strictly by gravity and airspeed. There was no way to lock them up in flight when they were retracted and no way to lock them down when they were extended. The only A-4s I ever saw static on the ground with the slats up were in maintenance and the slats were held up then with bungee cords to make it easier for maintenance personnel to work under the aircraft.

Now back to slat deployment in flight and the "dangers" of assymetric deployment. It was a non-issue. Period. It caught you by surprise the first time it happened (and trust ME, gents, it happened EVERY time you did ACM and a lot of the time in normal flight, especially if the rudder was slightly out of trim), but it was easily countered with stick and rudder with nothing remotely resembling loss of control. After a few times you got so you recognised when it was about to happened and just kicked the rudder pedals in both directions to get both slats out simultaneously, or nearly so. A total non event. Remember we had students flying these things with a total of 150 hours at the start, 300 at the end, and flying them in ACM pulling 6 Gs and formations and no accidents that I know of caused by the slats. Just not a big deal. Anyone who couldn't handle it didn't deserve gold wings.

So why did the Blues wire the slats up? First off, let me say I wasn't a Blue, and was out of the Navy when they went to the A-4 so I can't say with certainty, but taking into account what I do know, here are my thoughts. What do the Blues do? Precision aerobatics sound like a good description? So there they are in the diamond doing a loop, and we will assume normal slats. You look at them and see four aircraft in precise formation all but tied together, same speed, same attitude, same everything. Well, not quite. The four aircraft are on three slightly different radii paths and at three slightly different speeds: the lead is on the shortest radius and slowest speed, then the two wingmen, and the slot is on the longest radius and highest speed. So as they approach the top of loop and the slats want to come out, they will come out first for the lead, next for the wingmen, and last for the slot. Each pilot is contending with the slat deployment individually and at slightly different times and the formation will look anything but precise. Think about the delta formation on a left turning fly by at low speed (and the Blues don't fly at particularly high speeds or G loads, other than the solos): the inside guys are again on a shorter radius and slower speed and their left slat is going to want to deploy well before the outboard wingmen are anywhere near slat deployment. And this would be happening right in front of the crowd, not a mile or more above them. Dangerous? No, not at all. Unsightly? Yes. In reality it shouldn't happen, because the lead should manage to keep his speed high enough to prevent it, but if he has to tighten his turn to make the show line, it could be a factor and again the formation would look anything but precise. But if you wire the slats up it isn't a factor at all, so why risk looking like a bunch of plumbers?

Another thing I know is that the F-8 was rejected as a replacement for the F-11 for a similar reason: the fact that it was impossible to precisely coordinate the wing lowering on take off and the formation looked distinctly uncoordinated right after takeoff as the wings came down. That single factor mitigated against it, on all other aspects it was much preferred by all the 1966 team members who did the evaluation.

So that is what I think. I could be wrong and they wired them up because they thought it was a potential danger, but if so then they were worse plumbers than I know some of them to have been. The A-4 was as close to a viceless tactical fighter as I ever flew.

Now, as to Supertom's original question: just leave them up and don't worry about it. Remember all the kits that have them molded up. So what? says Red Zac!

Cheers,

Tom

[Mumbles]

Thanks for the clarification Superheat, much appreciated

[spejic]

Now, as to Supertom's original question: just leave them up and don't worry about it. Remember all the kits that have them molded up. So what? says Red Zac!

I'm pretty sure that of all the 1/72 A-4 kits made, the Fujimi is the only one that actually molded the slats open. Hasegawa, Esci, Matchbox, Italeri, and the others all made them closed. So like Superheat, said, just go for it. You will have plenty of company.

[GreyGhost]

How about a 'Heater-Ferris' schemed TOPGUN Scooter with a mottled green slat ?

(Photo: © Gregg Irons)

Gregg

[Collin]

How about a 'Heater-Ferris' schemed TOPGUN Scooter with a mottled green slat ?

(Photo: © Gregg Irons)

Gregg

That pic from sometime in the 80's? Looks like a fake canopy under there as well.

Cheers

ATIS