In the old days, why didn't aircraft use simpler systems to land on a Carrier?

Question

In the old days (during and before WW2), Carriers used arresting wires to help aircraft land. In fact this is still used today for jet-based carriers, but I want to ask about the old days with piston-prop aircraft because they go slower and generally make this easier.

I'm pretty sure even back in WW2, most carrier aircraft had tailhooks that grabbed the wire. This is so you "brake in the back", not the front. If you braked in the front, you are much more likely to nose forward or spin around.

Well, I've seen plenty of footage where that happens because something in the front of the aircraft, the nose or front wheels, gets tangled up in those wires, causing bad accidents. Here's a good compilation that has all sorts of landing accidents, including with the wire. What tends to happen is the wire is snagged wrong and the aircraft nose dives into the deck, wrecking the propeller, and/or the aircraft goes spinning around.

I can think of several alternatives to an arresting wire:

• Reverse Pitch Propellers (reverse thrust)
• Powerful Brakes in the rear wheel, or all wheels
• Drag Chute
• Air Brake

To me the simplest solution seems to be the last one, an Air Brake. I've seen this on modern jets like the Su-27 (@ 5:06). It's basically a big flat panel that swings out and creates enormous drag. In the Su-27 they keep it near the center of mass so it doesn't induce large torques, but you can put it in the rear half of the aircraft too. That will "brake in the back" and I think it won't require any more airframe strengthening than a tailhook, since that brakes in the back too.

So why not use this simpler solution? For reference, an Essex Class Carrier has a runway of about 260 m. I actually could not find normal "landing distance" that a small aircraft (bf 109, spitfire, etc.) needs once it touches down. If someone can find that, we would be closer to an answer.

Answer 1

The benefit of a cable is that it's a mechanical means of arresting the aircraft. You either catch the cable and stop, or miss and go around. Aside from breakage and malfunction, there is no in-between. If braking is left entirely up to the pilot, it's up to them to engage all the right functions quickly enough, and in sufficient amounts. If they misjudge, they end up going into the water.

Cables are also effective at stopping aircraft quickly. This means less deck space is needed for landing, and with the introduction of the angled landing area, allows aircraft to be launched and recovered at the same time. Only a tail hook is needed to be added to the aircraft, which adds great braking effectiveness for relatively little weight. Other options have reasons they would be less effective than cables, with greater penalties in areas such as weight.

Reverse Pitch Propellers (reverse thrust)

This can be an effective way to help slow a propeller aircraft down. The downside is that it's up to the pilot to engage the reverse pitch and in a sufficient amount. Single engine aircraft can be hard to control especially if higher power settings are needed while in reverse.

Powerful Brakes in the rear wheel, or all wheels

Brakes are limited by the friction between the wheel and the ground. On carriers, this was generally wood, later replaced by metal. Especially when wet, this does not provide very much friction. Increasing downforce (see the air brake section) can help, but only to an extent. And as you noted, especially with tail draggers used on early carriers, aircraft would nose over if they braked too hard. The tail wheel doesn't have much weight on it, so would not be effective in braking.

Drag Chute

You'll notice that pretty much the only aircraft that use drag chutes are aircraft that land at high speeds and already need long runways. This is where you get the most benefit from a chute; long landing rollouts at high speed. As speed is reduced, they become less effective. You need to spend the time recovering, repairing/replacing, and re-packing the chute after each landing. They are also going to be less reliable than a tail hook. If it fails, you can't land on the carrier, you may just have to bail out.

Air Brake

Air brakes are similar to drag chutes in that they work best at high speed. While they are are not a consumable item, the drawback is that they have much less area, and therefore much less effectiveness than chutes. They work best when they can also provide downforce to improve braking friction, but still need high speeds and long distance to really provide benefit.

Carrier aviation in World War II was certainly dangerous. Many pilots died in accidents rather than in combat. But the military was still learning about how useful carriers would be in combat, and figuring out what the best configuration for carriers and their aircraft would be. Carrier aviation has come a long way since then, and cables are still the go-to system for recovering aircraft that don't at least have some kind of STOVL capability.

Answer 2

Aerodynamic braking is of no use at low speeds: the braking force is proportional to airspeed squared, so at low airspeed you get a very low braking force. And that is not what is required in a carrier: the minimum airspeed is the stall speed, and this needs to be reduced to ZERO ground speed in a hurry, when on the deck.

This answer explains why the P51 Mustang could not be used for aircraft carriers: the stall speed was too high, even for the arresting hook and wire setup. Deploying an air brake either stalls the aircraft before landing or overshoots the deck in a hurry after touchdown.

Answer 3

In addition to what the others have already said, there was no need. There is a balance between the cost of something better and the actual benefits of it, primarily in terms of maintenance required, weight penalty to the aircraft, risk reduction, the amount of stopping distance required and sorties per hour.

While not perfect, the wire allowed for reasonably short stopping distances without adding too much equipment to the aircraft. During WW2 fighters required good performance to have a chance at shooting down their opponents. Adding extra and more complicated gear might reduce their performance while adding little of value if the only result is to make landings a bit easier. If the equipment is too complex, it requires more maintenance and might be easier to damage during combat.

Aerodynamic braking or reverse thrust requires a longer stopping distance, resulting in having to build larger carriers. This then drives the cost, making them a bigger and more critical to defend/keep out of harm's way as you can't build that many. And even today using STOVL, the aircraft is penalized with a lower payload and shorter range compared to conventional aircraft.

Answer 4

To add to the disadvantage of a drag chute. The now retired USCG HU-25 Guardian (military version of Dassault Falcon 20) had a drag chute attached to the tail cone for emergency landings or short runways. This was because the engines the coast guard used did not have reverse thrust capability.

This drag chute was only effective to about 60 knots. It was designed to quickly (and it did, you felt some dramatic deceleration) from initial touchdown speed to 70-60 knots. At that point it did very little, but the wheel brakes took over at this speed anyways. The HU-25 also had wing mounted airbrakes/spoilers. Again, these only assisted with slowing down. They were more effective at high speeds in flight to remove lift from the wing.

Even together, both of these systems still did not allow a landing anywhere near short enough for a carrier, unless you wanted to replace brakes and wheel's after every landings (they WILL catch fire, I've seen it)

As speed decreases so does effective of drag. So anything relying on a drag component will be ineffective when you really need it.

Answer 5

Several issues favored the use of arresting gear over good STOL capable aircraft, chiefly, adding STOL characteristics is often at odds with the requirements for a good fighter ie a low drag, highly maneuverable airframe couples with a high power to weight ratio engine. Adding features like a reversible propeller added excess weight to the design as well. Arresting gear also offers the option to recover aircraft at heavier weights or returning with unexpended ordnance, as opposed to having to jettison fuel and stores prior to landing.

There there’s the issue of straight deck carrier operations, namely that they often made use of only half of the flight deck for landing operations while the mid and fed sections of the flight deck was used for refueling, rearming and launching of aircraft. Landings on straight deck ships were a one way in affair; once the LSO gave you the cut signal, you were committed. Therefore the ship made use of multiple arresting gear plus a barricade to ensure the aircraft would stop before it plowed into personnel or airplanes on the midship. Going into the postwar period, jet aircraft increased in size and power requiring more space to stop them in which led to the development of an angled landing area. This offered both the real estate to arrest these heavier faster aircraft and also facilitated the option of a go-around in the event of a bad approach or a bolter.