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Skydiving

How to: the science behind Plane Swap

With the planning, testing and engineering help of Paulo Iscold, Luke Aikins and Andy Farrington will perform the first-ever dual jump between two planes in an epic April 24 livestream on Hulu.
By Jorge Martin
14 min readPublished on
The idea sounded impossible. Two solo-piloted planes diving toward the ground, with each pilot jumping from his plane then diving alongside and into the other plane. When the concept was presented to Paulo Iscold – an engineer, college professor and himself a pilot – he questioned the sanity of the person presenting the idea to him: Red Bull Air Force athlete Luke Aikins.
Iscold had first met Aikins after the skydiving master had jumped from 25,000 feet without a parachute and landed into a giant net in 2016. The professor of aerospace engineering questioned Aikins’ sanity, but after plenty of discussion Iscold could appreciate the science behind the daredevil act.
Luke Aikins and Paulo Iscold

Luke Aikins and Paulo Iscold

© Chris Tedesco / Red Bull Content Pool

The two remained more than casual acquaintances when Red Bull Air Force team member Kevin Coleman encouraged Iscold to talk with Aikins about the concept of two skydivers jumping from one plane into the others’ aircraft. Again, Iscold could hardly believe what he was hearing. ”He had the idea to swap airplanes in the air, it’s kind of crazy again,” Iscold recalled. “But nobody did that before, and I always liked the idea of getting involved in stuff that nobody did before. I told him right away, ‘I'm in, I want to do it. Whatever it takes, I will do it.’”
What started out as a crazy thought becomes reality on April 24, brought to you in a unique U.S. livestream exclusively on Hulu. During the live broadcast, Aikins and his cousin Andy Farrington will jump out of planes barreling toward the ground, maneuver into each others’ planes and take control of the planes and fly away. Sounds perfectly sane, right?
Luke Aikins in the Cockpit

Luke Aikins in the Cockpit

© Chris Tedesco / Red Bull Content Pool

Preparing for flight

Preparing for flight

© Michael Clark / Red Bull Content Pool

This is an event that has hardly been conceptualized, much less attempted. Never in the history of flight has a pilot taken off in one plane, and landed in another. Yet this milestone features not just one, but two pilots who are going to perform simultaneously a feat that may last all of 40 seconds, but will be an engineering marvel that will have taken the better part of a year to execute flawlessly. It became apparent that to execute such an incredible feat the pilots would have to not only have steely nerves but also to defy the laws of physics.
Plane Swap Drawing

Plane Swap Drawing

© Red Bull Content Pool

“There’s a whole bunch of very cool engineering going on, some fancy designs,” Aikins said. “The big thing is we have to prove that these planes, basically they change. It’s almost like a transformer. When we put this giant brake down and turn the engine off, it’s impossible for the plane to fly anymore. It’s now a falling object. This plane is no longer aerodynamically possible to fly. It’s just kind of falling through the air until you get back in it and switch everything over and turn it back into an airplane again so that it can fly. You couldn’t land it with this brake down.
“When this happens, it’s going to be one of those cool moments for me that we jumped through every hurdle. We took a lot of no’s, and here we are, ready to make it happen.”
One person playing a big part in making Plane Swap happen is Iscold, who has designed airplanes that have set multiple world records over the past two decades. Yet this is like nothing else he’s worked on before. Instead of flying faster, the goal is to slow down the planes as they’re barreling toward the earth. And while they’re doing it, they have to remain steady enough on that descent so that Aikins and Farrington can enter the planes and take control of the aircraft and fly away. That’s where the laws of physics are being tested. “The most natural idea was to use a drogue shoot, a parachute attached to the airplane,” Iscold said. “I asked him why don't you just do that? He said, ‘Well, the problem is, first, it doesn't look good because you always have these people who don't understand why the airplane is not going so fast while diving. But it's also difficult to develop because every time that you do a dive, you need to deploy the parachute and then you need to retrieve the parachute. So there is no way for us to test it, and what is important in this process is to understand that, yes, what they're doing is unique. We’re only going to do that one time, but we are approaching that problem step by step.”
Iscold broke down that step by step with a humorous analogy of how to eat an elephant; piece by piece. The team broke down the flight into the ascent to between 12,000-14,000 feet above the terrain, the leveling off, nosedive that includes the pilots jumping and swapping planes, then taking control of the planes and flying off. Yet as a true engineer, Iscold quickly found that there were a couple major problems that needed to be resolved. The aircraft needed to fly in formation straight toward the ground and remain steady enough for the skydivers to maneuver through the air and into a door about the width of a household refrigerator, but not quite as tall. Also, the planes need to “slow down” on the way down, because untethered the aircraft would travel at too high a speed for the jumpers to catch up… and the planes would soon disintegrate because of the velocity.
Preparing for flight

Preparing for flight

© Michael Clark / Red Bull Content Pool

So having the planes freefall was quickly ruled out, as was the aforementioned drogue chute. Iscold and the team came upon two solutions that would need to be developed exclusively for Plane Swap. First, they would have to create a speed brake that would not only slow down the plan on the dive, but also would help keep it steady. Second, the development of an autopilot would be able to control the planes as Aikins and Farrington exited and re-entered each others’ planes.
Planes in Free Fall | Plane Swap

Planes in Free Fall | Plane Swap

© Red Bull Content Pool

“I knew that what we needed to do for the project was to develop the speed brake system and to develop the autopilot system,” Iscold said. “That's another part that's unique on the project is normally the autopilot is designed to fly the airplane straight level and you cannot buy an autopilot that flies the airplane straight down. So we knew since day one that those were the parts that we had to develop. Very interesting that the same way that we thought that the speed brake would be way smaller, way simpler, we thought the autopilot will be able to track a point on the ground. You know, you just point the airplane to that point and make sure you fly towards that point. Very quickly through the development, we realized that no, you can't do that because you have wind. So the skydiver would be floating with the wind, you also need to allow the airplane to move with the wind. So they own the same mass of air. Those are the things that, you start a project, think that you're going to do it one way, but through the project you change your mind.”
Plane Swap Early Design Rendering

Plane Swap Early Design Rendering

© Red Bull Content Pool

The speed brake was complicated, because not only did it need to be able to slow down and steady the plane, but it also needed to be functional enough be able to become a part of the Cessna 182 airplanes. One of the team members, Ryan Malherbe, suggested a very clever way to affix the speed brake to the bellies of the planes. As the planes went into a dive, the speed brakes would be opened up and go perpendicular to the belly of the planes.
Planes in Hanger | Plane Swap

Planes in Hanger | Plane Swap

© Michael Clark / Red Bull Content Pool

At first the speed brake’s deployment was tested at an airport in San Luis Obispo near the college where Iscold teaches Aerospace Engineering. The planes would be lifted by a crane to test the lowering of the “barn door” as Aikins compared it to. That had several trial runs before they could test it in the air.
Once they tested in the air, there were multiple modifications, because early versions would not be able to tip the planes more than about a 70-degree angle toward the ground. A successful Plane Swap required a 90-degree dive. That’s when air flow became a necessary consideration. “Down Wash” became a term that grew quite familiar. How the air flowed not only around the wings but through the tails of the planes had to be calculated. A crack of air between the belly of the plane and the speed brake had to be created so that air could flow both above and below the brake and through the tail. “This wing is not symmetrical, so it has a little bit of curvature, which means that zero angle of attack it's producing a little bit of lift,” Iscold said. “So you need to place it a little bit over 90 degrees to produce zero lift. And why do we want zero lift? We want zero lift because when the airplane is going down, if you have a force, this force is making the airplane accelerate. And we can't afford that because the skydiver is going vertical to the ground. So that's why we need, let's say 90 degrees towards the ground, but the airplane will be at a 95-degree angle. So the airplane is at a little angle, but it's going 90 degrees towards the ground.”
Iscold’s calculations are that the entire stunt would take less than a minute once the planes go into tandem nosedives. “It's literally all the work that I've been doing for a year is for 40 seconds of dive flight,” Iscold quipped. “It's 365 days of work for 40 seconds of outcome.”
To maintain those nosedives it fell upon the autopilot that needed to be customized for this event. For this stunt to be a success, the planes have to continue to fly in controlled formation toward the ground and work in tandem with the speed brake. Iscold and Leo Torres, a fellow professor at Cal Poly San Luis Obispo, worked on the development of this automated system.
Plane Swap: Modifying the Cessna

Plane Swap: Modifying the Cessna

© Red Bull Content Pool

At first they created too precise a system. This would call for continual self-correction of the aircraft, which made it difficult for Aikins and Farrington to enter the planes. So the autopilot was modified to become “lazy,” as Iscold called it. This will hold the planes more steady to make it easier for re-entry.
The re-entry for each of the skydivers is tricky because even though the planes are not traveling full speed, they are still traveling about 140 MPH. The G Force has to be considered for how Aikins and Farrington will not only enter the aircraft, but to be able to get to the cockpit and hit the button to deactivate the nosedive and automatically correct the plane back to an angle so each pilot could take control and fly away.
Plane Swap: Andy Farrington in Training

Plane Swap: Andy Farrington in Training

© Red Bull Content Pool

“That was one of my concerns, the fact that the airplane is vertical and you can't sit on your seat anymore,” Iscold said. “I come with all sort of solutions to allow them to move inside the airplane while diving, but when we did the first skydive with the airplane, Andy grabbed the strut, crawls towards the airplane and placed his chest on the door frame, one leg and arm inside the plane, the other outside the airplane. At that position he can easily start the dive recovery process and then sit back on the seat. So, this is just an example that, as an engineer, it is super easy for me to create solutions for problems that actually don’t exist, and that is the reason that all the test flights during the development of the project are important.”
At that point, the speed brake becomes a detriment. As the plane steadies, velocity is necessary to fly away and complete the successful event. “After starting the recovery sequence, the airplane speed starts to decrease and we need to re-start the engine and immediately retract the speed brake,” Iscold said. "This will allow the airplane to fly again, come back to land and finish the sequence.”
The Plane Swap team has been testing these past several months at San Luis Obispo Airport, with support from Edward “Tres” Clements and Kyle Inks, from the company Aerocrafted. Iscold said the men and their company have given continual support in the development of all the customized parts for this unique project. Aaron Fitzgerald is another pilot who has been a part of the testing and practice runs for Plane Swap. “All these achievements are only possible when you work with a team and it's important for everyone around the world to select the best team that they can work with,” Iscold said. “This past year was an opportunity for me to observe how Luke works, how Andy works, how the team works and make my decision. Do we ever want to keep being part of this or not? And the decision so far is, I’m going to go all the way to the end with those guys.”
Luke Aikins and Andy Farrington Talk

Luke Aikins and Andy Farrington Talk

© Chris Tedesco / Red Bull Content Pool

The culmination for Plane Swap is over the Arizona desert on April 24 (don’t forget, it’s live on Hulu). Even though it will not be searing triple-digit temperatures that are the norm during the summer, the weather will be warmer than the climate in which they’ve been performing test flights in San Luis Obispo. That has been calculated as well.
Plane Swap: Flight Practice

Plane Swap: Flight Practice

© Michael Clark / Red Bull Content Pool

“There is a little bit of difference with the hotter temperature,” Iscold said. “The velocity that we fall, it's a little bit higher because the air is less dense. So we cannot afford to be too hot. That's the reason that we aim for late afternoon, because we should have more reasonable temperatures. High temperatures on the ground also produce more turbulence, but the conditions that we fly here in San Luis Obispo with the offshore wind are also very turbulent. So I think turbulence will not be a big deal for us in Arizona. I think what we are doing here is very similar to what we're doing there. Hopefully, San Luis Obispo will give us some good weather for the next test flights and Arizona will not give us a crazy hot day. So we're going to get the average on both sides.”
With interest building around Plane Swap, the questions the team has received typically in regards to how far the laws of physics can be tested. “One question that's coming up a lot recently from my students and other people here at the airport is why we're doing this, and if this will become a product or if there's a speed brake that can be used on another airplane,” Iscold said. “What I'm saying to people is it's not every project that we do that we need to save the world. It's OK to do projects that are just for fun and happiness is not the destination, it’s the journey, and I am enjoying the journey to get there. From the technological perspective, it's just a different challenge. It will not become a product. It will not make anything better in the world, but for sure it will make me sharper and better to solve other problems later on. What we're trying to do here is to inspire people, is to show people that no matter how big the problem is ahead of you, if you treat the problem well, and if you eat the elephant piece by piece, you can always eat the whole elephant.”
Plane Swap: Paulo Iscold

Plane Swap: Paulo Iscold

© Michael Clark / Red Bull Content Pool

Now that they have worked together and are nearing the finish line on another aviation feat that blazes a trail for others to follow, Iscold has very much changed his tune as to his first impression upon meeting Aikins.
“The difference between being crazy and being a genius, it's teeny tiny, is that right?” Iscold said “The most genius people in the world you look at them and you think they’re crazy. Luke, for sure, is on the genius side. You talk with him and you might think that his ideas are crazy, but in the back of his mind, he has a plan and those plans are pretty well put together. So, no, he's not crazy at all.”

Part of this story

Luke Aikins

Breaking boundaries is second nature to American skydiver and pilot Luke Aikins.

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Andy Farrington

Andy Farrington is a king of the skies with more than 26,000 skydives and over 1,500 BASE jumps to his name, not to mention about 6,000 hours as a pilot.

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