Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Reversing Mechanism  (Read 2244 times)

Ken S.

  • Shipmate
  • *
  • Offline Offline
  • Posts: 4
  • Model Boat Mayhem is Great!
  • Location: NYC-USA
Reversing Mechanism
« on: September 24, 2018, 02:31:43 am »

Hello Group:


I just picked up a Stuart Sirius steam engine and was wondering about my options to install a reversing mechanism.  I'm trying to get a layout set up.


Thanks for the thoughts.


Ken S.
Logged

derekwarner

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 9,464
  • Location: Wollongong Australia
Re: Reversing Mechanism
« Reply #1 on: September 24, 2018, 03:46:06 am »

Welcome Ken...it will certainly be of benefit to read as much about the Stuart Sirius engines  :o prior to any further work

Following is a somewhat lengthy paragraph from the Stuart home page....

"The Stuart Sirius was originally designed for racing steam hydroplanes. Particular attention was given to the valve gear and steam passage design with the result that the engine produces great power using a surprisingly low volume of steam. Our tests have shown that running at 2800 rpm the engine produces 1/3 bhp. at 80 psi"

https://www.stuartmodels.com/item/59/stuart-sirius-unmachined

The last sentence in the 2nd paragraph has me a little perplexed  O0

Derek
Logged
Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au

pendlesteam

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 75
  • Model Boat Mayhem is Great!
  • Location: Burnley UK
Re: Reversing Mechanism
« Reply #2 on: September 24, 2018, 02:56:43 pm »

As far as I know it cant be fitted with reverse. To reverse it would require a change in valve timing and there is no way to do this without making it a permanent change. Ive worked on a few of these and timing is critical.
Logged

malcolmbeak

  • Shipmate
  • *
  • Offline Offline
  • Posts: 22
  • Location: St.Albans
Re: Reversing Mechanism
« Reply #3 on: September 24, 2018, 03:31:06 pm »

     That’s quite right, the Sirius engine can’t be reversed. Some piston valve engines can be reversed by swapping the intake and exhaust, but the engine doesn’t run nearly as well. I have an old Stuart MTB1 which has the same basic configuration as the Sirius (twin cylinder single acting with a piston valve) and I’ve just tried swapping the intake and exhaust and it doesn’t work.
In any case the Sirius will not always self start as there are only two power strokes per revolution, and even if it could be made to reverse, in a radio controlled boat, you could be left with a model out of reach and no power.
Derek, I think the 2nd para. means only castings and gears are included unlike most of the other Stuart kits that include other materials, nuts , bolts etc.
     
Malcolm
 
Logged

TheLongBuild

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 4,748
  • Build em, and play hard..
  • Location: Everywhere, But Nowhere !! But mainly in England....
    • Runcorn & District Scale Model Boats
Re: Reversing Mechanism
« Reply #4 on: September 24, 2018, 06:13:38 pm »

I think My Modean engine goes faster in reverse,   %%   As can be seen going forward in this Months Model Boats Mag   :}

Ken S.

  • Shipmate
  • *
  • Offline Offline
  • Posts: 4
  • Model Boat Mayhem is Great!
  • Location: NYC-USA
Re: Reversing Mechanism
« Reply #5 on: September 25, 2018, 03:35:51 am »

OK, so no direct reversing mechanism for the Sirius, didn't think so but wanted confirmation.  Would a dog clutch type set-up be do-able?


Thanks for the welcome :-))


Ken
Logged

derekwarner

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 9,464
  • Location: Wollongong Australia
Re: Reversing Mechanism
« Reply #6 on: September 25, 2018, 04:28:02 am »

Ken......there is an option of using a Kitchen Rudder......[this is actually a variable reverse thrust bucket].....I understand they were used in steam engined Naval Picket or Pinnace boats around the WW1 period

Malcolm's comment about non self starting may be an issue to be considered ......so from this, it would be doubtful that the Sirius engine would be suitable for the loading/unloading clutching arrangement, however naturally a radio controlled throttle to limit engine speed should not be discounted

The following is just the search beginning.....

http://www.youtube.com/watch?v=WE02jxgGknc

https://www.scribd.com/doc/22985018/Kitchen-Rudders-Their-Inventor-and-Some-Applications

Derek
Logged
Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au

Ken S.

  • Shipmate
  • *
  • Offline Offline
  • Posts: 4
  • Model Boat Mayhem is Great!
  • Location: NYC-USA
Re: Reversing Mechanism
« Reply #7 on: September 26, 2018, 03:45:45 am »

Interesting but I think I should elaborate a little more.  I'm not intending on building a boat, even though I am soliciting info on a model boat forum.  I am desperate to get the information I need from the experts out there, especially on the steam end, from you guys who respond.  The basics I understand, boiler, engine (Sirius), water pump, condenser, throttle etc. but the drive train is perplexing me.  I'm building a steam engine driven tank built around the Sirius.  I think the dog clutch will work, maybe something based on the following design:


https://www.youtube.com/watch?v=TpQpAXu4wOg

[color=var(--ytd-video-primary-info-renderer-title-color, var(--yt-primary-text-color))]

Any suggestion on splitting the power to left and right sides tracks?


Ken S.
[/color]
Logged

pendlesteam

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 75
  • Model Boat Mayhem is Great!
  • Location: Burnley UK
Re: Reversing Mechanism
« Reply #8 on: September 26, 2018, 09:04:25 am »

Since the sirius rpm is so high you could use a centrifugal clutch like on model helicopters - cheap and simple
Logged

Ken S.

  • Shipmate
  • *
  • Offline Offline
  • Posts: 4
  • Model Boat Mayhem is Great!
  • Location: NYC-USA
Re: Reversing Mechanism
« Reply #9 on: October 01, 2018, 02:51:36 am »

Interesting on the heli centrifugal clutch. 


Maybe you guys can help me on the basics:


Fuel supply Butane/Propane (gas tank)
Burner
Boiler
Water Supply Tank
Water Pump
Super heater
Throttle
Engine
Lubricator
Condensor
Drive Mechanism
Forward/Reverse
Left/Right


Questions right now are:


1) Can I skip the condenser and pipe the exhaust directly into the water supply tank? Pros/Cons?
2) Can a boiler change angles significantly (~30 degrees) and still operate with water sloshing about.  Probably doesn't happen much on boats.


Thank you again.  I may form the as a new topic, at least for the steam part as I proceed with the design and construction.  Hopefully as I go along you'll enjoy building it with me. Thank you all again for your advice.


Ken
Logged

derekwarner

  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 9,464
  • Location: Wollongong Australia
Re: Reversing Mechanism
« Reply #10 on: October 01, 2018, 03:20:40 am »

[size=0px]Question 1. can the condenser be skipped & pipe the engine exhaust directly to the make up water tank?[/size]

[size=0px]No - the exhaust steam will be an emulsion of water + steam oil, this is why a de-oiler is used [not a condenser] the condensate will cool & [/size][size=0px]separate, however a small oil content remains. Oil [in any quantity] must not be injected into a boiler as it would result in the oil adhering to fire tube heating surfaces & hence progressively provide a surface that will reduce the transfer of heat to the water within the boiler [/size]

[size=0px]Question 2. can the boiler axis angle change to ~ 30 degrees?[/size]

[size=0px]A vertical boiler could be tilted to an off axis angle of ~~30 degrees & due to design still provide limited function, a horizontal boiler by design would not be capable of function at such angles [/size]

[size=0px]Derek[/size]
Logged
Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au

steamboatmodel

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 346
  • Location: Toronto, Canada
Re: Reversing Mechanism
« Reply #11 on: October 02, 2018, 03:47:01 pm »


Hi Ken,
How hard are you going to run the Sirius engine?
Most of the ones I have seen photos of are in Round the pole racing models and use liquid fuel (kerosene/paraffin and run flat out.
Gerald.
Logged
Be wary of strong drink. It can make you shoot at tax collectors--and miss. Lazarus Long
Pages: [1]   Go Up
 

Page created in 0.093 seconds with 22 queries.