boiler

[Alan]

Hi Guys
I have just completed my Stuart 10v, it turns nicely. (It worked very well on air) I made a simple 2 x 3" boiler (no leaks). However it does'nt matter how much heat i apply the engine will not run continuosly, it will turn over a few revs but then dies until pressure builds up again. Any thoughts and advice would be appreciated.

[Deleted]

Now I know that it runs on air..... then Havoc is quite correct as to boiler size. To drive a 48" launch my 10V needed a Martin Evans designed 3.5" dia x 8" long water tube boiler, fired by a 7/8" gas burner.
JB

[flashtwo]

Hi,

I had a similar problem with a Stuart D10 and found that the engine would turn at high revs and the pressure would drop rapidly.

Without a load any engine (without a governor) will run fast and act almost like an open ended pipe.

I connected the D10 to a 120 Watt DC motor (acting as a generator), the revs dropped down and the pressure was sustained. The DC motor is connected to a rheostat (variable resistor) and the load can be varied by turning the knob on the rheostat.

I did try a rope brake on the shaft, but found it was very erratic. An alternative would be a water brake with the engine shaft connected to a paddle, although varying the load would be difficult.

Ian