Rotor Blades

I started to make my own tail and rotor blades as I felt the commercial ones just weren’t good enough for my style of flying. Model kits came with wooden blades but if they were not sealed properly they could get damp and swell up. This meant that when they got dirty from the oil residue from the engine, they couldn’t be soaked to clean them up. They were also time-consuming to make as they would have to be made up with reinforcing strips, covered and painted, which was a lot of work. Another problem was they were not that strong along the length so in aerobatic manoeuvres they could twist which then affected pitch and ruined the flight. However, blades made out of fibreglass could overcome all of these problems, so I decided to make my own.

As with most things in life, this turned out to be more difficult than I’d expected. I had already made and repaired a few fuselages, so I knew how to fibreglass but this was only in polyester as I didn’t know about epoxy resin. The rotor blades I was using were made of wood and flexed a lot, so to stiffen them up I coated them with a polyester resin and fine cloth which was then sanded down. These were much better but the C of G was now in the wrong place, which led to instability. To cure this, I decided to make them completely out of fibre glass. I had no experience of doing this but the most logical way to me was to make them in two halves - top and bottom – and join them.

I made the plugs by sanding a wooden blade to the final shape I wanted and covered it with polyester resin reinforced fibreglass to make two moulds - a top and a bottom. These moulds were then polished to help with the release process and a gel coat put in place that would become the surface of the new blade. Cloth and polyester resin were then laid onto the gel coat. For the leading edge I had a friend with a spindle moulding machine make some up out of obeche veneer. These were quite heavy, so I decided not to put anything into the trailing edge. While the cloth layers were still wet, the top and bottom halves were clamped together and left to cure overnight. I was pleasantly surprised when the first blades came out as they looked quite good.

Unfortunately, as the blades spun up I could see them start to ripple which I concluded was due to nothing being in the trailing end. I thought about putting in wing ribs like those in an aeroplane but rejected this as it would be a very long process. I then tried injecting two-part foam into the hollow blade but as well as filling the cavity it also caused the blade to bulge destroying the profile I wanted to achieve. In the end I managed to solve this problem by shaping a piece of foam and placing it in the mould as the skins were being created.

I now had to find a way of weighting the front of the blades in order to get the C of G in the right place. Initially I made a groove in the leading edge and filled it up with lead. This seemed to work as on the next test flight the blades tracked true with no vibrations. But as I went to fly a circuit the blades disintegrated in mid-air causing the helicopter to blow up. The hole I had drilled for attaching the blades to the blade grip had split causing the blade to fail, so I knew it had to be reinforced.

Despite all these setbacks, they were a blessing in disguise in that they taught me how to build a rotor blade that was not only efficient but was also strong. The revised design included a leading edge spar made out of fibreglass that encapsulated a lead weight and a reinforced root. These were a complete success and I started to win more and more competitions. As well as making the machine more stable, my own design blades made auto-rotations a dream. I won these competitions easily as I could really load up the blades to create so much inertia that you could hover the helicopter just above the ground with no engine and have a cup of tea!

This success generated many enquiries for the blades. First my mates asked me for a set, so I started making and selling them at my local club field. This then extended into model shows and I started to think that this could be the way to finally make a living out of the hobby.

I started selling 10 sets a month, then 20, then 40 a month. My best month was 50 sets. Most of our business came through word-of-mouth but after only a short time I was selling direct to customers as well as to retailers. And it just wasn’t in the UK, the business extended to sales in the USA, Canada, New Zealand and Japan. I didn’t employ anyone – it was just Olive and I making them. We would have up to 12 moulds for each blade design but as there were small marks in each mould we would make sure that we paired up blades from the same mould. We created our own production line. Olive would polish the moulds while I made the leading edge. Olive would cut the cloth to shape and we would both lay up a blade half each. These would then be joined and left to cure overnight.

Business was good. For example I would go along to the Sandown symposium with 300 pairs of blades and sell every one of them. I didn’t make a fortune but it got us by for the next 20 years. Towards the end though, the market started to get competitive. When I started there were only three companies that made blades but now everyone seemed to be making them. Both the design and quality had improved to the extent that our ‘home produce’ seemed irrelevant. I also found it boring so we decided to finish the blade making business and look for something else to do. To bring matters to a head, one mad day in the late 1990s I picked up all the blade moulds and took them down the tip and got rid of them. There was no going back. I still made my own blades but not for anyone else.