Korey Kiepert, the lead engineer behind Tayto Park’s Cú Chulainn Coaster, explains how he went from making models to building the real thing. Kiepert has worked on some of the world’s most impressive roller-coasters and his latest, set for Co. Meath, will be one of Europe’s largest wooden coasters, David Jackson reports


This year is set to be a big one for Tayto Park. Earlier this year, founder Ray Coyle unveiled the park’s latest major attraction, The Cú Chulainn Coaster, which is being built at the amusement park in Ashbourne, Co Meath.

Along with being one of Europe’s largest wooden roller-coasters it will also be the only one of its kind on the continent. Ground was broken on the project on August 10, 2014, and construction commenced on the September 1, 2014. Tayto Park has employed the services of globally renowned roller-coaster engineers, the Gravity Group from Cincinnatti, Ohio, which has created more than 50 wooden coasters around the world, including the first ever wooden model in China. A team of 70 engineers and builders have been hard at work to ensure that the ride will be completed by this summer.

Picture2Tayto Park has been inundated will calls and emails from roller-coaster enthusiasts hoping to ride the attraction on its first day. One fan has even requested the use of the roller-coaster to propose to his girlfriend on its opening day.

The coaster, which will have a strong Irish mythological theme, will boast impressive proportions for a wooden inverted ride. With more than 800,000kg of yellow pine wood transported from the southern USA, more than 100 tonnes of steel and collectively more than 700,000 nails and bolts, the Cú Chulainn Coaster will include a stomach-churning drop of more than 33m.

Gravity Group Collaboration

The Gravity Group has more than 40 years’ collective experience both designing and constructing some of the world’s most adrenaline-fuelled roller-coasters, working on 73 of the attractions around the world. The Gravity Group’s Korey Kiepert, the primary engineer responsible for building the Cú Chulainn Coaster, told the Engineers Journal how the idea for the Tayto Park machine came about.

“Raymond Coyle and Charles Coyle, both of whom are heavily involved in Tayto Park, attended an amusement park convention that happens every year in Orlando, Florida, hosted by the International Association of Amusement Parks and Attractions (IAAPA).

“During the IAAPA show we connected and started discussing the possibility of adding a wooden roller-coaster to the park. Tayto Park has a lot of animals, buffalo, tepees and a western American theme going on, a wooden roller-coaster seemed like a natural fit with the natural surroundings of the park which includes animals, trees and landscaping. A wooden roller-coaster seemed like a better fit with the park rather than some giant steel machine that would stand out much more.”

Early career and inspiration

Kiepert puts his interest in roller-coasters down to his parents bringing him along to Cedar Point amusement park in Ohio every summer as a young boy. He has gone from making model roller-coasters in his wardrobe, to getting married on one and now he is making a living designing and building them.

Korey Kiepert at the Tayto Park Rollercoaster 2“We used to come home from Cedar Point and my brother and I would build roller-coasters out of cereal boxes. We tried to recreate the amusement park in the wardrobe. I had a fascination with that and I was a mechanically inclined person, taking apart the toaster and the can opener.

“I remember reading an article about somebody who designed rides and thinking, wow, that would be cool, I want to do that.”

Korey went on to study mechanical engineering at Michigan Technological University and following graduation secured himself a job with an engineering firm working on wooden roller-coasters. The company, Custom Coasters International, closed down in 2002 and Corey, along with some of his colleagues, founded The Gravity Group. It has gone on to design and build some of the world’s most impressive attractions.

World renowned Gravity Group projects

“There have been a couple of rides that particularly stand out. We did one that opened in 2009 in Shanghai and that was the first wooden roller-coaster in mainland China. That was an experience, an interesting project from a cultural standpoint. Wood is a non-traditional building material for the Chinese and so they would be more afraid of a wooden roller-coaster than a steel ride that might loop 12 or 13 times. “

The Gravity Group is also responsible for The Voyage, the fourth largest largest wooden roller-coaster in the world located at Holiday World & Splashin’ Safari, Indiana. A recent project in Sweden, the Twister at Gröna Lund in Stockholm, required the use of a 3D scan to weave the ride through two other roller-coasters while maintaining the required clearance height.

“Twister at Gröna Lund was very complicated, it is a very compact park and it didn’t have much space. Twister had to go over, under and through several other roller-coasters and rides, so it made for a very challenging ride. We had to get a 3D scan of the park so that we could weave our ride in and around other rides and maintain the required clearance height.”

Engineering advances and wooden roller-coasters

Wooden roller-coasters are preferred by many for their personality and the way in which they can be tailored to suit their surroundings. One of the outstanding features of the Cú Chulainn Coaster is a turn banked at 115 degrees. As riders travel the curve they will be technically upside down, which is a first for a wooden roller-coaster in Europe.

Older wooden machines can jar riders due to their uncomfortable cars but Kiepert insists that this will not be the case with the Cú Chulainn Coaster. Engineering advances mean that the Tayto Park attraction should be a much smoother and more comfortable experience for riders than the traditional models they may be used to.

“The cars that we have rolling on the Cú Chulainn Coaster track are very sophisticated. Traditional wooden roller-coasters have cars that have four fixed wheels and you ride around in a box.

“The cars on this ride will be steering cars, so instead of having fixed wheels, this ride is going to have wheels similar to an automobile where you might have a tie rod between wheels.

“With the tie rod system there is a steering mechanism so you are following the path of the ride instead of having fixed wheels that kind of bang around the track. It’s an example of some of the engineering advances that we have been making in roller-coaster design.

Picture1“I have been working on wooden roller-coasters for close to 20 years now. When I started we were just using these trains that hadn’t changed much in 100 years and now we have a very sophisticated train that is like a sports car in comparison to a Model T on the track.”

Further technological and engineering advances have made the key features on the Cú Chulainn Coaster possible. Although it is a timber track an adhesive is used between layers in specific high stress areas to give the track some extra stiffness and stability. The track itself is required to twist very quickly at the point of inversion; Kiepert said centre laminates were used to make that twist possible.

“When we do the inversion, where we have the track upside down, we have to twist the track very quickly and in order to do that we have used a centre laminate on our track. With these new cars that steer, they articulate more so they allow us to do these features like going upside down.

“We couldn’t have done that as easily before, we might have been limited by the vehicle on the track to only a certain amount of twists per metre of track and now that is a much higher number.”

Structurally a lot of changes have taken place in the design process of a modern wooden roller-coaster. If you looked at a wooden model that was made 10 years ago it wouldn’t resemble some of the structural details used by the Gravity Group. Along with structural changes has come increased responsibility in terms of track safety. Kiepert concluded by explaining some of the changes that have taken place in this area.

“There have been different changes in the timber codes, whether it is Eurocodes or our own American Codes, they make recommendations about certain connection styles that are better than others. We try to steer towards having all of our connections meeting those criteria.

“On the Cú Chulainn Coaster, for instance, you will see that we use a lot of steel plates in places where with a roller-coaster maybe 10 years ago, they would have used wood connections.

“In the past there used to be much more flexibility for the people in the field. There were carpenters who might have made changes to the ride to make things work. On the plans that we provide there are thousands of drawings that we create for this ride and this structure so that we know where every hole and every bolt is located on the ride; because of that we are able to have confidence that we meet the criteria for what is given in the codes.”

http://www.engineersjournal.ie/wp-content/uploads/2015/05/Korey-Kiepert-at-the-Tayto-Park-Rollercoaster1-1024x683.jpghttp://www.engineersjournal.ie/wp-content/uploads/2015/05/Korey-Kiepert-at-the-Tayto-Park-Rollercoaster1-300x300.jpgDavid O'RiordanMech3D,Meath,United States
  This year is set to be a big one for Tayto Park. Earlier this year, founder Ray Coyle unveiled the park’s latest major attraction, The Cú Chulainn Coaster, which is being built at the amusement park in Ashbourne, Co Meath. Along with being one of Europe’s largest wooden roller-coasters it...