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Micro Chuk Williams Combustion Chamber

Posted by lohring 
Micro Chuk Williams Combustion Chamber
January 16, 2015 04:23PM
The first step toward a radio controlled flash steam power plant is the combustion chamber. Thanks to Chuk, I got a lot of information on his Land Speed combustion chamber. Mine is a 4" diameter version with some simplifications. I'm waiting for the fuel pump speed control to test it. Below and following are pictures.

This is the complete unit.

Re: Micro Chuk Williams Combustion Chamber
January 16, 2015 04:27PM
This is the inner liner with swirl plate and baffle. The inner liner was cut from a stainless steel water bottle. As you can see from the lable, that makes it a green combustion chamber. The allen head screws act as spacers from the bottom of the outer liner.

Edited 1 time(s). Last edit at 01/16/2015 04:40PM by lohring.

Re: Micro Chuk Williams Combustion Chamber
January 16, 2015 04:32PM
This is the vaporizor coil. The needles brazed to the lower coil are hypodermic needles that act as nozzles. They are a lot easier than drilling #75 holes in the stainless steel tube. Also they can be aimed if needed. The inlet is tapped for the Festo quick connect fuel fitting you can see in the assembled picture.

Edited 1 time(s). Last edit at 01/16/2015 04:38PM by lohring.

Re: Micro Chuk Williams Combustion Chamber
January 16, 2015 04:37PM
This is the blower, an electric ducted fan unit, and the view of it mounted in the outer can. The last picture shows the inside of the complete chamber.

Re: Micro Chuk Williams Combustion Chamber
January 16, 2015 05:21PM
Nice work and very interesting design, please post updates to your progress.

Re: Micro Chuk Williams Combustion Chamber
January 23, 2015 01:30PM
That looks like something the guys building an educator speedie wagon or similar project could use....
Is there some place for a model jet ignitor...looking forward to your updates.
Re: Micro Chuk Williams Combustion Chamber
January 24, 2015 10:16AM
For now I plan to warm the vaporizer coils with a propane torch and then turn on the blower and fuel pump. After I connect the combustion chamber to the boiler I'll add a propane nozzle and a glow plug for ignition. I just got the pump speed control and have wound the boiler coils. The housing and a burner test are the next steps. An Arduino control program will be the hard part.

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
January 24, 2015 04:35PM
Is this for a hydroplane?
Looks an interesting project but one observation, having googled the fan you are using - it needs a lot of amps!! I suppose if the model aircraft chaps can live with that, so could you with it in a boat!

Re: Micro Chuk Williams Combustion Chamber
January 25, 2015 12:18PM
This steam power plant will go into an outrigger hydroplane similar to the 26 to 30 cc gasoline engine powered boats. Below is the hydroplane we used to set the gasoline powered hydroplane record in 2004 that still stands. The steam engine will be based on one of these gasoline engine crankcases with a custom cylinder and piston. I also race electric powered boats. The fan speed controller will be from one. It's rated at 120 amps continuous with a 240 amp burst. We routinely pull over 100 amps through it. The fuel pump controller is only rated at 20 amps. I was hoping a large servo driver would run it but it pulled 5 amps and the controller overheated. The boat will have an onboard lithium polymer battery to run all the motors and electronics.

The testing breadboard setup will have an electric motor driven water pump as well. The boat that motor is from is a national race winner that holds several records. It can easily handle 200 amps at 30 volts for a 6000 watt (8 hp) output. It's speed controller includes data logging so I can get some idea of the pump power requirement. The final water pump will be engine driven with a variable stroke. That way steam production will be related to engine rpm and only need some fine adjustment (I hope).

Lohring Miller

Re: Micro Chuk Williams Combustion Chamber
January 25, 2015 06:42PM
Nice,some of brits actually have mono tube programming language and ecu that they literally build and program for them things.Can't remember the names,but is pretty popular among the hobbists.All are fast enough that you have to see them to believe how fast they run....
Re: Micro Chuk Williams Combustion Chamber
January 26, 2015 05:23PM
The only electronic control system I'm aware of is for a moderate power system. The seriously fast flash steam hydros all run direct drive fuel and water pumps at a set flow. They run wide open all the time. The only RC flash steam boat I know about has an off/on control.

I would be very interested if anyone has more information on electronic monotube boiler controls.

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
January 27, 2015 12:18AM
Arduino should work, I am currently learning about it for the controls on Kristies Flyer.
Re: Micro Chuk Williams Combustion Chamber
January 27, 2015 08:17AM
I'm planning on an Arduino as well. However, there are a lot of basic questions. The old monotube controls ran constant pressure and temperature. The temperature was controlled by a normalizer. A throttle controlled engine output. The above mentioned electronic system tried a lot of things but found that constant temperature controlled by the burner with engine output controlled by water feed rate was the most stable. In the past constant temperature with the output controlled by boiler pressure was advocated,

Is there any modern experience with this?

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
January 27, 2015 01:48PM
The temperature stability in a monotube forced circulation steam generator was controlled by varying the water flow rate even with a fixed firing rate. The normalizer is a more or less safety override device, because the wildly varying loads in a steam car could and did cause the outlet temperature to vary unless you had some way of matching the feed rate to the water use rate.
Dobles initial idea that the compensator was enough was wrong, so then they added the normalizer.

White did it by constantly modulating both the water feed rate and the burner fuel pressure.
Doble had a two stage water feed rate, the compensator for taking care of the water rate depending on just how fast the pumps were running, and the normalizer to act as a final control if needed.
In the first Series E cars the normalizer had its own solenoid control contact in the control box. Later the normalizer was simply connected to the second set of water pump solenoids, because the thermal inertia masked any instant temperature swings as long as the four pumps had caught up with the water demand.
Re: Micro Chuk Williams Combustion Chamber
January 28, 2015 08:30AM
Thanks for the corrections to my over simplified version of the historic control systems. I'm still interested in any experiences with modern electronic controllers. The one referenced above is the only one I can find. I expect that throttle input will go into the Arduino with the blower, fuel pump and water pump as outputs. The big question is how do you use the pressure and temperature inputs to get the desired result. And, by the way, what is the desired result? How do you use temperature and pressure to control the power? I've read about Jerry People's and the Carter's variable pressure systems. Is that the answer?

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
January 31, 2015 04:46PM
I got the boiler mostly together. A little insulation on the outside and some fittings will make it ready for testing. The water pump is next. The first picture is the coil of 1/4" 316 stainless tubing. The next pictures show the assembled boiler and combustion chamber.

Lohring Miller

Re: Micro Chuk Williams Combustion Chamber
January 31, 2015 05:58PM
Hi Lohring:

I have some history with drum-type boiler coils, having used an R.J. Smith "Maxi-SASS" boiler in my steam car in the 1970's.

Smith used a somewhat different (and unique as far as I can tell) method of control for this unit; it relied on the fact that the coil stack was welded into a unitized assembly, using short lengths of weld between every coil to its adjacent neighbor. The coil assembly BTW consisted of an outer economizer section concentrically placed over the inner "superheater" coil, with spacers placed in the inner coil and then welded into place along with the welding of the tubes into a rigidized assembly. The control method I'm discussing involved only the inner coil, which was directly exposed to the flame and first pass of the flue gases.

The concept utilized the fact that the drum coil (having been thus unitized) could utilize the expansion coefficient of the entire coil to become a temp sensor. Smith used this effect for several purposes: 1) To provide an overheat shutdown feature; 2) To modulate (i.e., turn-down) the firing rate as the superheat approached the target value.

When combined with rate-controlled feedwater (again, Smith's genius created a simple but elegant solution to this) the result was a successful boiler control with minimal hardware.

Based on the photos you have submitted I believe you may be able to weld your tube stack into a rigid assembly using modern processes such as TIG or plasma welding without compromising its function. The use of stainless steels (with their higher coefficients of expansion) makes this a viable method of control IMO.

Please note: This method of control doesn't need to "know" where the evap section ends, it can be adjusted by simply observing the final output values. Also note that the classic Doble style and similar with pancake coils isn't amenable to this solution--only the "drum" style will work.

I can provide additional details as necessary, and Karl Petersen probably has a greater knowledge base and should be consulted for his opinions.

Re: Micro Chuk Williams Combustion Chamber
January 31, 2015 06:30PM
Sorry, another post:

Please watch this youtube vid clip, I have some (hopefully) relevant comments about it:


First, this effort (in the steam generator) seems to mimic the configuration which has been used successfully in quite a few steam hydroplane efforts, referring to the tethered speed-oriented types.

Before moving to some possibly interesting observations, I would also like to note that here we have yet another example of a youtube "junkie" producing what seems to be a successful project--but using hardware which is not only inappropriate, but even dangerous!! Are you kidding, a plastic coke bottle pumped up to 100 psi to supply feedwater (typical carbonation pressures in these is about 50 psi BTW)--and no check valves between the coke bottle and the boiler so if something goes bad he will get a faceful of hot steam and water. Duh!!

On to the observations: 1) It's interesting to note that engine speed/power (?) is being controlled solely by feedwater input to the steam generator coils, and appears to be consistently controllable. 2) There is no way to know what the steam pressure and temps are--but based on this vid clip and all the interesting on-line sites about Kirtley and others it appears they are just aiming for the highest possible temps and pressures. Control be damned!

So, it looks like "forget the controls" and work on proportions instead. The following parameters would need to be matched: 1) Firing rate. 2) Feedwater rate. 3) Total area of coil. 4) Etc., etc.

Comments invited,

Re: Micro Chuk Williams Combustion Chamber
February 01, 2015 10:57AM
Thanks for the thoughts and the video. I plan to try a variable water input as the throttle control as well. My boiler is based on Bob Kirtley's design shown below with input from George Thompson's design. I believe electronic systems should be more adjustable and ultimately simpler than mechanical systems. We'll see if I'm smart enough to make it all work. My favorite mechanical system would be the Waterman variable pump system. I have several designs for piston pumps that should work, but as the white paper points out, there is no experience with a high temperature and pressure power plant.

I'm trying to use proven designs as much as possible. There aren't many model size high pressure boilers. I picked Chuk's combustion chamber as a mildly pressurized design as contrasted to the natural aspirated designs the tether boat people use. Efficiency isn't a factor, but controlability and high heat release is. We'll see how it works with the long tube arrangement. Model boats have diameter limitations that are more severe than length. Tether boats run at full throttle all the time. I understand it takes a lot of fiddling to get the water and fuel feeds right. Direct drive pumps take care of matching the pumps to engine rpm. I'm sure that gives reasonable adjustment over a narrow operating range.

Today I plan to run some burner tests with propane and map gas. Next week I'll try the fuel pump with kerosene.

Lohring Miller

Re: Micro Chuk Williams Combustion Chamber
February 03, 2015 09:24PM
There is a piece on the monotube pattern that the club brits are running in International steam society.The the pattern is the Pisces II that set the class B steam record at 104mph.
They are using Proton compiled basic that looks something like the text document below.Which for free and written by Anderson.
You build the your controler board that is ran by the board that is deplayed below.
Part of what made the monotube work was "tuning" for a speed thru 3/16" tubing at 50meters a minute to strip the bubbles off the tube walls for best heat transfer.
The article also has a list of all the microchips that you can control with Proton.Hopefully a model can pickup run with the model hydroplane "outsider" didn't know....


'Issue F4s now iss F5
'Addition to stop pump running during cut-out period

'T1 (MP1) senses temp of water return to hot well coil (infomation only)
'T2 (MP2)senses temp of exhaust from steam engine or feed water from economiser (infomation only)
'T3 (MP3) senses temp of steam/water from main coil
'T4 (MP4) senses temp of steam from separator (infomation only)
'T5 (MP5) senses temp of steam output from superheater
'P senses pressure of steam at outlet from separator

Include "PROTON_G20X.INT"

'Version based on SERVO_ADINBOLDav

ADIN_RES = 10 ' Set number of bits in result
ADIN_TAD = FRC ' Set clock source (3=rc)
ADIN_STIME = 100 ' Set sampling time in uS

Dim x As Word
Dim Raw0 As Word
Dim Raw0a As Word
Dim Raw0b As Word
Dim Raw1 As Word
Dim Raw1a As Word
Dim Raw1b As Word
Dim Raw2 As Word
Dim Raw2a As Word
Dim Raw2b As Word
Dim Raw3 As Word
Dim Raw4 As Word
Dim Raw5 As Word
Dim Value0 As Word
Dim Value1 As Word
Dim Value2 As Word
Dim Value3 As Word
Dim Value4 As Word
Dim Value5 As Word
Dim Scale0 As Word
Dim Scale1 As Word
Dim Scale2 As Word
Dim Temp0 As Word
Dim Temp1 As Word
Dim Temp2 As Word
Dim Temp3 As Word
Dim Temp4 As Word
Dim Presure As Word
Dim Shut As Bit
Dim Shut2 As Bit

Dim w As Word
Dim G As Word
Dim z As Word
Dim o As Word
Dim F As Word
Dim b As Word

Symbol Pin0 = PORTB.0 ' Alias servo pin
Symbol Pin1 = PORTB.4
Symbol Pin2 = PORTB.5
Symbol Level = PORTB.7 'Alias float level switch (used only to operate pump' manually)
Symbol Pump = PORTB.6 'Alias Feed pump "Pump"

'Position the servo

Input TRISA ' Set PORTA to all input
TRISB = %11110000 ' Set PORTB.0-3 to output
PORTB = 0 ' Set PORTB.0-3 low
ADCON1 = %10000010 ' Set PORTA analog and right justify result
TRISE = %00000001 ' Set PORTE.0 To Output
PORTE = 0 ' Set PORTE.0 low
TRISB.6 = 0 ' Set PORTB.6 output
Shut = 0
Shut2 = 0
z = 0
G = 0
F = 0
b = 0

' Main program loop


For x = 1 To 5 'go round servos loop 5 times for each display loop


Raw0a = (Value4 / 16) + 390 'Set S/H temp. ( = Open at aboutC150, Closed at about 195C)
'Raw0a = (Value4 / 8) + 110 'Set S/H temp. ( = Open at about170C, Closed at about 195C)
'Raw0a = (Value4 / 8) + 90 'Set S/H temp. ( = Open at about175C, Closed at about 206C)
If Raw0a > 650 Then GoTo jumpover8
If Raw0a > Raw0b + 5 Then Raw0b = Raw0b + 1 Else Raw0b = Raw0a 'dead band & slow up responce (small changes)
If Raw0a < Raw0b - 5 Then Raw0b = Raw0b - 1 Else Raw0b = Raw0a
If Raw0b < 600 Then GoTo jumpover0
If Raw0a > Raw0b + 50 Then Raw0b = Raw0b + 3 'dead band & slow up responce (large changes)
If Raw0a < Raw0b - 50 Then Raw0b = Raw0b - 3
If Raw0b < 600 Then Raw0b = 600 'Limit servo travel (600 = max, 640 = 60%)
If Raw0b > 700 Then Raw0b = 700
If Raw0a < 650 Then Shut = 0: GoTo jumpover5

If Shut = 1 Then GoTo jumpover6
If Raw0a > 670 Then Raw0b = 700 : Shut = 1 : GoTo jumpover5 'Snap open/closed secondary burner to 25% for ignition or shut-off

If Raw0a < 660 Then Raw0b = 650 : Shut = 0

DelayMS 10
Scale0 = Raw0b -600
If Scale0 < 1 Then Scale0 = 0
If Scale0 > 100 Then Scale0 = 100
Scale0 = Scale0 * 14
If Presure < 60 Then Scale0 = 1400 'Disable s/h outside pressure range 60-85
If Presure > 85 Then Scale0 = 1400

If b > 450 Then b = 450 'Disable s/h for frist 3 mins
If b < 450 Then Scale0 = 1400
Servo Pin0 , 1000 + Scale0

DelayMS 10


If Value5 < 1000 Then Value5 = 1000 'NEW
'Raw1a = (Value5 / 30) + 480 'Gas valve porpotinal to pressure, ( = open at 60PSI shut at 80PSI, )
Raw1a = (Value5 / 20) + 380 'Gas valve porpotinal to pressure, ( = open at 65PSI shut at 80PSI, )
'Raw1a = Value5 / 9 'Gas valve porpotinal to pressure, ( = open at 70PSI shut at 78PSI, )
'Raw1a = (Value5 / 10) - 30 'Gas valve porpotinal to pressure, ( = open at 83PSI shut at 90PSI, )
'Raw1a = Value5 / 10 'Gas valve porpotinal to pressure, ( = open at 78PSI shut at 87PSI, )
'Raw1a = (Value5 / 8) - 100 'Gas valve porpotinal to pressure, ( = open at 74PSI shut at 80PSI, )
'Raw1a = (Value5 / 11) 'Gas valve porpotinal to pressure, ( = open at 88PSI shut at 95PSI, )
'Raw1a = (Value5 / 12) + 30 'Gas valve porpotinal to pressure, ( = open at 90PSI shut at 99PSI, )
If Raw1a > 680 Then GoTo jumpover18
If Raw1a > Raw1b + 5 Then Raw1b = Raw1b + 1 Else Raw1b = Raw1a ' dead band & slow up responce (small changes)
If Raw1a < Raw1b - 5 Then Raw1b = Raw1b - 1 Else Raw1b = Raw1a
If Raw1b < 600 Then GoTo jumpover1
If Raw1a > Raw1b + 50 Then Raw1b = Raw1b + 3 'dead band & slow up responce (large changes)
If Raw1a < Raw1b - 50 Then Raw1b = Raw1b - 3
If Raw1b < 640 Then Raw1b = 640 'Limit servo travel (600 = max, 640 = 60%)
If Raw1b > 700 Then Raw1b = 700
If Raw1a < 680 Then Shut2 = 0: GoTo jumpover15

If Shut2 = 1 Then GoTo jumpover16
If Raw1a > 699 Then Raw1b = 700 : Shut2 = 1 : GoTo jumpover15 'Snap open/closed burner to 25% for ignition or shut-off

If Raw1a < 681 Then Raw1b = 680 : Shut2 = 0
DelayMS 10

Scale1 = Raw1b -600
If Scale1 < 1 Then Scale1 = 0
If Scale1 > 100 Then Scale1 = 100
Scale1 = Scale1 * 14

Servo Pin1 , 1000 + Scale1
DelayMS 10
Next x

b = b + 1


z = z + 1
If z = 2 Then z = 0:GoTo jumpover20 ' set pump on period - 2

Pump = 0
G = G + 1
If G > 100 Then G = 100 'Enable pump at 8:2 for 90 secs after start or reset
If G < 100 Then Pump = 1
If G > 101 Then Pump = 0

F = F + 1
If F < 24 Then Pump = 0:GoTo jumpover20 'set pump off period (2 to 19) (5 = 5:1)
If F > 24 Then F = 24tongue sticking out smileyump = 1

If G < 100 Then Pump = 1:F = 16:GoTo jumpover20 'pump 8:2 for first 2 mins
If Temp2 > 178 Then Pump = 1:F = 21:GoTo jumpover20 'pump 3:2 T3 > 178
If Temp2 > 170 Then Pump = 1:F = 18:GoTo jumpover20 'pump 6:2 T3 > 170
If Temp2 > 160 Then Pump = 1:F = 11:GoTo jumpover20 'pump 13:2 T3 > 160
If Temp2 > 150 Then Pump = 1:F = 9:GoTo jumpover20 'pump 15:2 T3 > 150
Pump = 1:F = 0 'pump 24:2 T3 < 150
If Level = 1 Then Pump = 0: F = 0: G = 100 ' Pump can be turned off manually during first 3 minutes
If Level = 1 Then Pump = 1 'Pump can be turned on/off manually after 1st 3 minutes

Raw0 = ADIn 0
Raw1 = ADIn 1
Raw2 = ADIn 2
Raw3 = ADIn 3
Raw4 = ADIn 4
Raw5 = ADIn 5

Cls ' Clear the LCD
' Quantasize the result
Value3 = Raw0 *10 'Raw0 is T4 Temp3 Separator steam out, For information only
Value4 = Raw1 *10 'Raw1 is T5 Temp4 for controlling superheater burner
Value5 = Raw2 *10 'Raw2 is P5 Pressure For controllimg Main Burner
Value0 = Raw3 *10 'Raw3 is T1 Temp0 Heat exchanger to hot well.For information only
Value1 = Raw4 *10 'Raw4 is T2 Temp1 Feed water to main heater coil For information only
Value2 = Raw5 *10 'Raw5 is T3 Temp2 Output from main coil. For controlling feed pump

Temp0 = Value0/46 '0-220 Deg C
Temp1 = Value1/46 '0-220 Deg C
Temp2 = Value2/46 '0-220 Deg C
Temp3 = Value3/46 '0-220 Deg C
Temp4 = Value4/23 '0-440 Deg C
Presure = Value5/80 '0-120 PSI

Print Font TIMES_BOLD14 ' Choose the font

Print At 0,0, "T1 = ", DEC3 Temp0," C" ' Display the result
Print At 10,0, "T2 = ", DEC3 Temp1," C"
Print At 20,0, "T3 = ", DEC3 Temp2," C"
Print At 30,0, "T4 = ", DEC3 Temp3," C"
Print At 40,0, "T5 = ", DEC3 Temp4," C"
Print At 50,0, "P5 = ", DEC3 Presure," PSI"

'Print At 10,90, DEC3 b 'Use this section to display diagnostic information
'Print At 20,90, DEC3 G
'Print At 30,90, DEC4 Raw0a
'Print At 40,90, DEC4 Value4

If b < 450 Then Print At 0,65, "Warm-up"
If b < 450 Then Print At 10,90, "2"
If G < 100 Then Print At 10,90, "1"
If Pump = 1 Then Print At 40,90,"Pump"
If Temp2 > 173 Then Print At 20,70, "HI"
If Temp3 > 170 Then Print At 30,70, "HI"
If Temp4 > 205 Then Print At 40,70, "HI"
If Presure > 100 Then Print At 50,75, "HI"
Print At 50,104, "F5" 'Show software issue number

SerOut PORTC.6,T9600,[DEC3 Temp0,44,DEC3 Temp1,44,DEC3 Temp2,44,DEC3 Temp3,44,DEC3 Temp4,44,DEC3 Presure,44,DEC4 Scale0,44,DEC4 Scale1,44,DEC1 Pump,44,10] ' Output serial data comma delimited(44), CR/LF(10).
' 5 temps, pressure, 3 servo positions
'OVER TEMPERATURE/PRESSURE SHUT DOWN ' Use Baud 9600; no parity; Byte size 8; 1 stop bit
' Will only work properly on Lap-top
If Presure > 100 Then GoTo closevalves ' Close primary & secondary valve if temp exceads limits
If Temp2 > 185 Then GoTo closevalves
If Temp3 > 175 Then GoTo closevalves
If Temp4 > 220 Then GoTo closevalves

GoTo Again
Print At 10,65, "Over Temp"
Print At 20,65, "Cut-Out"
Print At 30,65, "Wait"
Print At 40,65, "1 min"

For w = 0 To 50 'Set S/H gas valve closed
Servo Pin0 , 2400
DelayMS 10

Servo Pin1 , 2400 'Set gas valve closed
DelayMS 10

Pump = 0 ' Stop pump during cut-out

Next w

For o = 1 To 60 'Reset cut-out after 1 mins
DelayMS 1000
Next o
G = 100
b = 300
GoTo Again
' Load the fonts used

Include "TIMES_BOLD_14.FNT"
Re: Micro Chuk Williams Combustion Chamber
February 04, 2015 07:43AM
Thanks. That will take some study. At first glance it looks like a propane fired burner. The really high power engines like Pieces II use kerosene from an engine driven pump. Also, I'm not aware of tether boats using a steam seperator. Is there a link to the articles?

Lohring Miller

Edited 1 time(s). Last edit at 02/04/2015 07:47AM by lohring.
Re: Micro Chuk Williams Combustion Chamber
February 05, 2015 05:48PM
My bad on the address...I was so used to Woodson having website references right there ,that forgot this site doesn't.
www.steamboating.org which is the International steamboating society....he was also building a launch so that might have been water tank.
Also on my own 240D project,a combined cycle 40hp.diesel with 100hp.recirculating turbine.....used the burn can off the gas turbine left the control on pressure and revs hooked up to throttle the burner in additon to normal burner controls (the diesel is your blower).You can usually get double the horse on half the heat of gas turbine.(free turbine seems to work better for conversion to steam)But the burner and coil on the Lamont in the tailpipe looks pretty close to what yall were doing.Hopefully the Lamont won't be chewing up the last 1/5 of the coils as bad as monotube does.
Would like seeing Scotland ...and the brit steamers sometime.Been about 200 years since the family left debtor prison in Scotland and worked in Virginia as indentured blacksmith on plantation.
There is also something reference to Brit. publications that I have never seen on the mono hydroplane stuff.
Re: Micro Chuk Williams Combustion Chamber
February 06, 2015 11:58AM
This is a brief summary of Ian Gerrard's electronic monotube control system. Any thoughts?

Lohring Miller

"The main difference with my control system compared with the “traditional” ones that control steam temperature with the pumps and pressure with the heat input, is that I don’t bother controlling the pressure, since both heat input and feed flow affect it.

The next control loop is the steam temperature, which is measured by a thermocouple in the boiler steam outlet manifold, and is compared with the desired temperature usually a couple of degC above steam saturation temperature. The controller then operates a servo controlled gas valve to modulate the heat input.

By having a pressure independent feed flow, very stable control is maintained throughout the power range – this is what makes this system so different to that used over the last one hundred years.

To increase the boat speed, I increase the desired feed flow setting and the more water going into the boiler the more steam comes out and the engine speeds up (and vice-versa).

The current control system detects changes in feed water demand by looking at the incoming signal from the transmitter.

With an increase in feed demand, rather than wait for the outlet steam temperature to drop, it “heads them off at the pass” by opening up the gas valve in anticipation.

The amount of opening and its duration depend on the change in feed flow demand and a manual offset setting of desired steam temperature.

Likewise, if there is a reduction in feed demand, then the gas valve closes in anticipation of a rise in steam temperature.

This method of feed forward control is tunable by manually amending the sensitivity of the gas valve control to feed demand changes."
Re: Micro Chuk Williams Combustion Chamber
February 06, 2015 04:26PM

What you have described is a control system for a variable pressure generator. Of course-as mentioned-the control steam temp is set a few degrees above saturation. So, as the pressure goes up the sat temp goes up accordingly and so the control temp,etc,etc,etc. By controlling the feedwater input, then, you are controlling everything else.

It sounds like it should do just what we're all looking for-control of a monotube! A bit of trim might be needed to make things dead on, but for use in one of your steam plants-it sounds good-eh?

Re: Micro Chuk Williams Combustion Chamber
February 07, 2015 10:11AM
That's what I hope. However, I plan to run quite a lot of superheat. I also have a blower as well as fuel feed to contend with. I noticed that the Carters still used a throttle as well with their variable pressure system. The mechanical simplicity of a variable pressure system is very appealing. The electronics should scale up.

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
February 14, 2015 10:25AM
I've been running the combustion chamber on propane and it all works well. Turning on the blower gets things red hot in a hurry. I need to rebuild the nozzles since some flow better than others. That gives uneven heating. The fuel pump is working as well so the next tests will be with Coleman fuel or kerosene when I solve the nozzle problem. I got an oxygen sensor to calibrate the fuel flow to blower output. I'll post some pictures when it all works.

Lohring Miller
Re: Micro Chuk Williams Combustion Chamber
February 14, 2015 02:11PM
Finally, even flow through the nozzles.

Lohring Miller

Re: Micro Chuk Williams Combustion Chamber
September 25, 2016 09:12AM
After a long pause to get my business started, I'm working on the RC flash steam engine again. The boiler is on hold while I build the engine. Below are pictures of the cylinder block and liner on a 23 cc gasoline engine crankcase. Next will be the piston and Dykes ring.

Lohring Miller

Re: Micro Chuk Williams Combustion Chamber
September 26, 2016 03:03AM
Read something about fan/blower speed controller being used, this one works good op to 10 amps 12vdc. Its the one I have selected for my combustion chamber. I used it the other day for a combustion test, and the speed controller worked flawlessly. I still have to install jets in the air passages

Re: Micro Chuk Williams Combustion Chamber
September 26, 2016 08:38AM
Thanks so much for the website. Had two like it 15 or more years ago(cost $30 then), and after using one on Rod Teel's Lamont on the circulating pump put another on Craig Standbridge's steam ruck for a variable speed exhaust stack blower---they were terrific. Then I could never find the source again! Thanks much.
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