A Bluebird X7 First run

[BESM]

I just finished my first hydroplane - a model of Donald Campbell's Bluebird X7.
I am quite pleased with it and grateful for the advice I have had and the posts I have read on this forum.
Here is a the link to a video

https://www.youtube.com/watch?v=SEzGwatBYZs

The thing that interested me the most was the relation between prop speed and boat speed.
It looks to me like there are two stages in getting up to full planing.
The first stage happens starting at about 12 mph and the second at about 27 mph
I am guessing that at first, the sponsons start to plane while the aft end is still in the water. The second stage starts when the prop lifts itself up half out of the water.

I am a newbie to this sport so I may be all wrong but it's fun to speculate.

The other thing that happens is that it sometimes capsizes but then rights itself and just carries on. This has happened on two separate occasions. I hope to be able to film this event.

Bruce

Bruce

[srislash]

It’s a good looking model. Kudos to you for taking the time to put together this info. It is fun and good experience to dig into all the data.

Shawn

[Peter A]

Great model. Some thoughts to consider and perhaps try. The cutting out may be due to the esc being too small. A 90 amp esc may be better. As the model is designed to do only doing straight line runs, you could probably shorten the rudder and have a little less drag and get a little more top speed.

[BESM]

Thanks Peter

My mistake, on checking my order from Offshore, I find that indeed I have a 90A ESC already. It is really invisible without stripping the boat to confirm.
Yesterday's running over an hour indicate that the ESC casing temperature stabilizes at around 100F but of course it's hotter inside.

Very good idea to shorten the rudder since the boat turns with alacrity. Obviously I don't want to affect the water pick-up so I will shorten the rudder to ,say, 1/2" below the water port. The real boat had a very small rudder in fact

On this subject, it is interesting to see how the ESC temperature swings with time. It is the black line on the attached graph over a ten minute period taken yesterday. It is very similar in characteristic to the run history in the video which also shows the temperature rising about 10F during the first bursts of running and holding this until the next sequence which shows a temperature drop followed by a rise. My takeaway is that the water cooling is working otherwise there would not be a drop in temp.

Bruce

[vvviivvv]

Can't load the video as at work but some great info on bluebirds here

https://www.modelboatmayhem.co.uk/fo...html#msg754734