EDF Jet Boat (Bluebird K7) SPEED TESTING

by JamesWhomsley | July 20, 2017 | (6) Posted in Projects


(Main Documentary Style Film)

(Secondary In Depth Look at the Build)


This was an extremely satisfying project to undertake and complete. It pushed my RC experience into new territory, experiencing both the challenges of hydrodynamics and aerodynamics in one machine. I also experienced a taste of what one of my heros, Donald Campbell, must have felt - the waiting for the right weather conditions, the frustration of something not being quite right, and the jubilation of success. 

For all of you who are interested in the design and development of the craft, the following may be interesting reading to you:

As mentioned above, the experience of working with both air and water was particularly challenging. The way that Bluebird was required to plane up onto it's three points to be able to skim across the water whilst staying balanced was difficult to get right. The only way to see if everything would work was to test it. 

Almost immidiately, it was evident that something was wrong.

The problem came from the water splashing up and deflecting off the rear sponson (float) supports and into the intake of the ducted fan. 

For a while I wasn't sure whether simply deflecting the water away from the intake would be enough - I still had to fix the problem of the rather square shaped rear supports deflecting water upwards and causing a great deal of water resistance. A flash of inspiration revealed a solution: I would simply attach a curved piece of plastic under the support which would also act as a 'skid'. This would not only stop the water resistance, it would actually help Bluebird aquaplane up onto its three points! A fizzy pop bottle was cut up that evening and we were ready for the next attempt. 

The second test run was far more successful in getting Bluebird to skim across the lake. It managed to get up onto its plane and travel along at a calculated 30mph. For the model's size, this was a scale speed of around 150mph. For a first proper go, this was a great result! The sight of Bluebird ripping up the lake was fantastic to see. 

Unfortunately, on this first run up Coniston, Bluebird experienced a loss of signal whilst in the middle of the lake. This was due to the ESC coming in contact with the water that had leaked into the hull. As this electronic component was not waterproofed, it failed, leaving the boat stranded and in need of rescue.  

Thankfully we had a dedicated team on standby.

Bluebird was recoverd, missing it's rudder and with a rather dead ESC. Despite this, there were smiles all round and celebrations. It had worked! Mission complete. The aim to get Bluebird to run on Coniston, irrespective of how many times it went up the lake, was achieved in spectacular fashion. 

So what next for Bluebird? Currently, the hydroplane is out of action, with a fair bit of work needed to replace its ESC and to fit a more rigid rudder system if it's fan is to wirr again - which would be ideal. With goals achieved, this project has reached its natural conclusion. There are some inherent problems with the design, especially in using foamboard as the primary material. For this reason I think that I may just keep the boat in the best condition I can by not running it on water again, at least in the forseable future. However, as with most projects, this has inspired another.

I will most probably build another hydroplane at somepoint, an original design which will aim to break a real record, or at least go as fast as possible! For now, here's a tick next to a project on a list that has been there for a very long time.


I hope that this project has inspired you to get out there and complete a project of your own that you have always wanted to do. If you found this film and article interesting, entertaining or informative, please give the article a rating and a comment, and also be sure subscribe to my Youtube channel to show your support. 

Many thanks - James.

Further Reading, including the complete collection of photos from the build, can be found on my webiste - www.projectair.co.uk 


Gryf on September 4, 2017
Splendid work! And how fitting that you were able to take it to Coniston.
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JamesWhomsley on September 5, 2017
Many thanks!
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Scottmclam1 on July 18, 2018
That was simply awesome.
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Razor7177 on August 17, 2018
Good job mate. I noticed your nozzle was a little to big, try half the edf diameter. And try thrust vectoring for the steering, worked on my project, just not at high speed.
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EDF Jet Boat (Bluebird K7) SPEED TESTING