Retired Engineer Built A Roller Coaster For His Grandkids

From telling them stories to taking them for walks to baking them cookies, grandparents’ main job is to help their grandchildren have fun. Outdoor play is in many ways the healthiest source of enjoyment, which is why grandparents often focus on building swing sets, tree houses, and sandboxes for their grandkids. This allows them to take advantage of the extra time they have in retirement, leaving an enduring source of enjoyment for their beloved grandchildren.

Paul Gregg sought to do the same for his grandchildren, but as a retired aerospace engineer, he had the expertise to go above and beyond. Seeking to give his grandkids endless entertainment, he built them a roller coaster for their backyard. The result is an inspiration to grandparents everywhere, showing them just how much joy they can bring to their descendants with a little extra expertise and effort:

40. A Background With Boeing

Paul Gregg had spent more than 34 years of his life working for Boeing as an aerospace engineer. The experience made him an expert in science and safety, two fields of knowledge that are every bit as important for entertainment as they are for air travel.

39. Committed To The Children

After retiring, Gregg devoted all his knowledge and skills to the benefit of his grandchildren. He imagined how his expertise could enrich their lives, and quickly settled on building a roller coaster as the most engaging answer.

38. Critical Cupping

As with any rail project, the first step was to design a track that would keep the car safe without slowing it down. He devised a machine that would cut cupped edges for wooden boards, fitting them snugly into a rounded rail line.

37. Cupping Closeup

The key was to cut the boards in half in a way that rounded their edges inward. The rounding had to be consistent, so he designed a wooden mold to hold the boards in place for the same cut.

36. Drill Diligence 

A drill press would provide the power for a clean, thorough cut, ensuring that no part of the track was insufficiently or unevenly cupped. All would have the same circular hole with a 2-inch diameter.

35. Environmental Enhancements

In addition to cupping the boards, he treated the wood and applied a deck stain material. This would ward off rot, water damage, and other environmental threats, keeping the roller coaster sturdy and safe for years.

34. Pairing With Pipes

Once the boards were ready, the next step was to attach them to the rail lines, which he had made with PVC pipes. He screwed each pipe to the edge of the board and installed a tie every 16 inches for stability.

33. Rail Resources

To build the rail lines, Gregg glued a small piece of PVC pipe inside of a larger one. He locked the boards to the rails with two screws on each side.

32. Gauge Set Steadiness 

For each length of the track, he used a gauge set to hold the materials steady. This would allow him to measure the track carefully and screw each part in place without fear of disruption.

31. Laying Out Track Lengths

After making each length of track, Gregg laid the pieces out and began to prepare for construction. Planning was necessary to figure out where he would bend the tracks to fit his intended design.

30. Diligent Diagramming 

Gregg created a detailed diagram to determine where he would need to place each length of the track. He arranged the lengths strategically so that he would have to do as little bending and cutting as possible.

29. Designed With The Deck

To minimize the number of support structures he had to build, he used his deck as a foundation for the beginning of the tracks.

28. Energy Evaluation

As an engineer, Gregg knew how to calculate the potential and kinetic energy that the cart would have at each section of the track. Taking this into account was essential for ensuring both the safety and the enjoyability of the ride.

27. Fortified Framing

In addition to the cart’s energy, Gregg also had to determine how energy would reverberate through the frame. He tested the rails thoroughly, making adjustments to the structure and lines in order to shore up safety.

26. The Frame In Focus

This structure served as the model for all of the track’s frames. Its triangular design directed pressure inwards, ensuring that the track would remain sturdy even when transporting a fast cart bearing significant weight.

25. Concrete-Free Connections

For the frames to work, they had to be attached sturdily to each other. Ordinarily, Gregg would have done this with concrete, but his wife vetoed that because of the damage it would do to his backyard. He thus opted for a careful wood arrangement instead.

24. Track End Enhancements

Gregg made the end of the track taller than the start to ensure that the cart would not have enough energy left to fly off. He also widened the track for further security.

23. Slowing To A Stop

By making the final part of the track so steep, Gregg ensured that the car would ease into a stop, rather than jerking dangerously to a halt.

22. Peak Prudence

Other than the very end, each of the track’s peaks was lower than the preceding one. This would provide a varied, bumpy ride without wasting energy, ensuring that the cart would be able to reach the end.

21. Deft Digital Models

Once the track was ready, the only major step remaining was to design a cart for his grandkids to ride in. He used an online modeling software to experiment with different designs before building.

20. Selecting Steel

Making the model also gave him the chance to consider different materials for the cart’s foundation. He opted for tubular steel, which would provide a sturdy and resilient base to ride on.

19. 2D Diagrams

Once he had finished designing a digital model of the cart, he produced a 2D diagram. He would be able to consult this more easily while putting the cart together.

18. Determining Dimensions

When creating the diagrams, it was crucial to mark the dimensions of each part of the cart clearly. This allowed him to make accurate measurements and cuts, which were essential for safety.

17. Surmising The Sides

Gregg made detailed dimensional diagrams for each side of the cart. This would let him visualize the entire unit at once while he was constructing it, never losing sight of the final product.

16. Wheel Wisdom

For each corner of the cart, Gregg installed two wheels: one on the top and the other on the side. This would prevent the cart from moving off the tracks without taking away kinetic energy.

15. Roller Blade Repurposing 

To make the side wheels, Gregg repurposed wheels from roller blades, while employing standard longboarding wheels for the top units. He also hung a small piece of PVC pipe from the bottom for makeshift lower wheels. 

14. Acute Alignment

After optimizing all of the wheels for the rails, he placed them on either side of a piece of track and clamped them in place. This would ensure that the foundation was properly aligned when he welded it together.

13. Wise Welding

The cart was essential to the safety of his grandchildren, so Gregg was not going to cut corners in making sure it held together. Using his skills as an engineer, he welded the metal in place.

12. Tenacious Testing

As safe as the cart and track were in theory, testing was necessary to ensure it would work in practice. He thus filled the cart with the equivalent of his grandson’s weight…

11. Positive Performance

…and set it flying! The cart performed exactly as expected, indicating that it would be safe for Gregg’s grandkids and their friends to ride the roller coaster.

10. Metrical Measurements

As an engineer, however, Gregg was not about to rely on eyesight alone to assess performance. He placed his smartphone in the cart, activated an accelerator app, and set it flying again.

9. Empirical Evidence

The data from the smartphone confirmed what eyeballing had indicated: that the cart was safe for a human rider. His grandkids could now take advantage of their new toy.

8. Grandson Gauging

Gregg’s grandson decided to be the first human test subject for the roller coaster. As you can see from his expression, he was a little wary of the new device…

7. Emerging Excitement

…but that wariness quickly turned to excitement as soon as the ride began! Gregg’s efforts were clearly meeting with success, and this was only the first ride!

6. Car Seat Concerns

As much fun as the first ride was for his grandson, it did raise some concerns about using a car seat for the cart. Gregg didn’t like how the car seat affected his grandson’s head.

5. A Cushioned Cart

To replace the car seat, he designed a new cart with heavy interior cushioning. This would provide a safer compartment.

4. Evaluating The Enhancement

As with the original cart, this new travel compartment was ready to be tested by his grandkids.

3. Fun & Functional

The new cart was just as fun as the old one, but lacked its predecessor’s risks. The roller coaster was thus complete.

2. Reasons To Return

Gregg’s hard work gave his grandchildren a reason to keep coming back and visiting him. Why go to Disney World when there’s a free ride that is just as fun in the backyard?

1. Gregg’s Roller Coaster Guide

Gregg’s DIY roller coaster was so successful that he published a guide for other grandparents, allowing them to give their grandkids the same great experience.

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