Why engineers make great grandparents! Retired aerospace worker builds three ROLLER COASTERS in his back garden for his grandchildren 

By Paddy Dinham For Mailonline

Published: 10:48 EST, 2 December 2016 | Updated: 10:51 EST, 2 December 2016

A former aerospace engineer is keeping himself busy in retirement by constructing roller coasters in his back garden for his grandchildren to enjoy.

Paul Gregg, who worked for Boeing for 34 years, has designed and built not one but three different rides at his Seattle home.

And now he has uploaded a video of two of his six grandchildren testing out one of the timber and metal contraptions.

Mr Gregg has to push the cars up the first hill himself, but once the cars have picked up momentum they take themselves around the track

He has even gone to the trouble of adapting one of the carts to look like a racing car, and the other a rocket ship

He has to push the cars up the first hill himself, but once they have picked up momentum they take themselves around the track with no need for further human intervention.

The little boy and girl are having a whale of a time as they complete circuit after circuit, screaming and laughing as they go.

Mr Gregg has even gone to the trouble of adapting one of the carts to look like a racing car, and the other a rocket ship.

This particular coaster is known as the Little Rocket, and is actually the smallest of the trio in his garden

The little boy and girl are having a whale of a time as they complete circuit after circuit, screaming and laughing as they go

This particular coaster is known as the Little Rocket, and is actually the smallest of the trio in his garden.

The largest is known as Smaug The Terrible, while there is also the Negative G ride which takes kids partially up a slope before sending them back in the direction they came from.

He has written a book on back yard roller coasters and is now providing help to parents hoping to copy him. 

Comments (89)

Share what you think

 View all

The comments below have not been moderated.

 View all

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

Add your comment

By posting your comment you agree to our house rules.

Who is this week's top commenter? Find out now