Kent, WA5VJB recently gave a talk on Yagi antenna construction and designs for the UK Microwave Society and it is now on their YouTube page.
This talk should be of interest to anyone interested in building their own Yagi antennas for the VHF and UHF bands.
The talk lasts for about 38 minutes with a short 10 minute Q&A session after it.
WA5VJB also has his own website which has antennas and equipment for the microwave bands here... https://www.wa5vjb.com/index.html
YU7EF in Serbia is a well known designer of HF and VHF beams and many radio amateurs worldwide use his designs. In this post, we will look at two 5-element Yagi antenna designs for the new 40 MHz (8-metre) band.
(Updated 30th Dec 2020... Thanks to Pop, YU7EF for the additional information)
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A) Design #1 : EF0805S - 5-element Yagi on a 4.5 metre boom
The design with dimensions is shown below.
The calculated gain in free space is about 7.5dBd and has a front to back ratio in the region of 25dB.
Thanks to Dragan, 9A6W for sending on this YU7EF design for a 4-element Yagi antenna for the new 40 MHz (8-metre) band.
The design with dimensions is shown below.
The calculated gain in free space is about 6.2dBd and has a front to back ratio in excess of 20dB.
Not only are they using a 3 element on 160m but they have a 5 element yagi for 80 metres above it!! 
.......a rail inside the boom for walking on!......at 100 metres above ground level!.........any volunteers??