Stage 4 Testing Preparation and Review

Stage 4 Testing Preparation and Review

Like everybody else we are adjusting ourselves to life under a partial lockdown while governments and research organisations everywhere look for ways to mitigate and control the spread of the Corona Virus. We are proud to tell you of the work being carried out by model builder Len Newton who has joined with fellow 3D printer owners to produce face shields for local care homes and nursing facilities. Thank You Len.

While everything is in partial limbo, it’s a good time to take stock of where we are and what we plan to do next once we can get to the test lake. The original Crusader 1 model is fitted with a jet built by Len. That gave us a baseline for power and weight which we could apply to the first Crusader 2 model produced in fibreglass. Of course we had no real idea about how heavy it would be until it came out of the mould. Too heavy was the short answer. However, until you test you don’t know so we went ahead with tests to collect information. The boat ploughed rather than planed with water making its way into the jet intake. Even that was a valuable lesson since knew for sure that we needed more buoyancy and better sealing of the internal structures. We also decided that we needed more power.

More power came in the form of an off-the-shelf Mammoth micro jet along with a lightweight tailpipe. This was fitted to the C2 model which then underwent more tests to see if it showed any sign of getting up on to plane. At the suggestion of Lorne Campbell we produced a whole series of temporary shields and spray guards. This improved things but not to the point where it would get on to plane. What Lorne really wants is close up film of the bow wave pattern as the boat ploughs. The spray guards should help with this.

But just to be sure, and since we can’t yet test, Len has produced a C2.V2 model in carbon fibre. And to be really sure, he has fitted a temporary top mounted scoop as used on modern unlimited hydroplane race boats. That model is just about the same weight as the original C1 model. So, with three boats, two engines of differing power output and a variety of shields to test, we should be able to get that all important detailed film. Once Len is allowed out that is and film maker Graham Fordham can join him. In the meantime, here are some photos of C2.V2 being built with the top mounted scoop. There is also a home movie so you can get an idea of how the Mammoth jet sounds.

We are pretty certain that getting the weight, weight distribution, power and angle of attack for the front planing shoe correct will lead to us knowing how Railton’s design behaves. We are equally certain that the original wooden model was never his final version so it will be interesting to see where the model testing and computer modelling by Adam Stringer at Falmouth University leads us. RAR would have been as fascinated as us that’s for sure.