Saito steam engine

[Derek Warner]

The only way I found the Saito "STEAM ENGINE SITE" is via a goggle search on saito, the scroll
down through all the references until you get to the WWW.hhq.com.au/saito/saito.htm site
(page 2 of the goggle search

& when you log on to the steam section look at the Y2DR paddle engine!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I know I said it wouldn't be sporting to install an Asian engine in a XXXXX nationality paddler, but if I
had AUD$1925.00 to spare I would seriously consider the engine & boiler kit

The AUD$ costing is from the (Australian) r2modelmarine current catalogue pricelist - page 14

regards Derek

[Derek Warner]

Hi Stuart - how are the steamings of Reliant in the past months ? - good I hope - the notes below in
the previous posting are self explanatory, however I have a few questions

1) your snaps of Reliant Puffin engines would suggest say a 4:1 chain drive reduction???

2) the current (new) Cheddar site gives little detail of any individual components size, weight or
no load speed - do you have any idea of the Puffin engine no load speed (@ 30 PSI)?

3) the Saito site suggests 3500 RPM no load speed for the Y2DR side wheel engine of 0.035 HP
@ 2Kg/cm2 = 30 PSI approx

4) my rough calcs confirm that two Cheddar Puffins have a swept displacement of 7.6 CC, where
as one Saito Y2DR twin has a swept displacement of 7.5 CC

5) I do acknowledge the boiler technology as offered by Cheddar is literally 20 years in front of the
competitors but at what cost???

any thoughts or comments- regards Derek

[Stuart Badger]

Dear Derek and all

the water trials of Old Trafford continue - in some cases with frightening
results!!
I removed about a kilo (2 lbs) of ballast so that she floated on her water
line rather than just below it. While using the paddles differentially to
execute a turn she suddenly heeled to about 45 degrees, lifting the inside
paddle out of the water and burying the outside hull of the ship below the
surface of the water - by stopping everything I just got her back and
removed about 4 pints of water!

Now, several things become obvious to me at this point (and this does tie in
with your questions). Firstly one puffin would be MORE than adequate to
power the model ( 50inches and about 35lbs weight). If two engines are to be
used then I would suggest that you ONLY use them independantly from rest. ie
when turning the model about its axis at very slow speed. At all other times
use the rudder! (you may have to increase the area from scale) and certainly
if you are modelling a 'skinny' (ie a cross channel steamer with a high beam
to length ratio) on NO ACCOUNT have the paddles operating independanty -
install that paddle shaft as one unit!. I would even go so far as to suggest
that unless you REALLY want to be able to 'turn on a sixpence' then fix the
shaft even on a model with a low beam to length ratio (such as a tug).

gearing the paddles (you're right at 4-1 chain drive) - I don't now think
this is necessary if using a STEAM engine. The reason for this thinking is
that steam produces maximum torque at zero revs, and the engine is perfectly
capable of starting the paddle from rest ungeared - it also gives much
gentler acceleration and finer control. In fact with the geared wheels the
power available is so high that you can spin the paddle wheel so fast that
the resulting asymetric thrust is very destabilising. We have discussed
paddle speed on this forum extensively. I'm now going to put the cat amongst
the pigeons and go back to my original estimate of about 60 rpm being
correct (for Old Traffford) . I know this may seem terribly slow - but don't
forget that 60rpm represents 480 'pushes' a minute with a paddle wheel
having eight floats. Old Trafford's speed seems unaffected once you get over
this rotational speed (maybe due to cavitation) - but her stability is
devastated at anything over about 80rpm! and all that happens at higher
paddle speeds is that an enormous fountain of water is hurled out behind the
model whilst the paddle box vents spew water in all directions!

I don't know what the no-load speed of the Puffin is, but I would guess
about the same as the Saito.

I can't comment about the quality of Saito steam plants - I used to sell
them years ago in the model shop I worked in and they seemed very well made.
As regard your comments about cost - Cheddar may seem a lot of money but
they are NOT expensive. In terms of durability and reliability they probably
come out better than any other form of propulsion unit.

There is another manufacturer of steam plants here in the uk:
Stour Valley Steam
Applecroft
Watery Lane
Pillerton Hersey
Warick CVB35 0PQ
Tel/Fax +44 (0)1789 740371

They don't unfortunately have a web page or (as far as I can tell) an email
address.

If members want I could ship Cheddar products direct to them if that would
cut down the cost, but I imagine Cheddar would be more than willing to do
this themselves.

I'm fortunate in that I can indulge myself but I appreciate that the engines
are a lot of money. I guess it's a question of 'wants' versus 'needs'! To
put an electric motor/s in Old Trafford would have been cheaper, easier to
operate, easier to install et al - BUT, for me, it would have been
deparately disappointing not to have the experience of sailing a model
powered by the most exciting method of motivation known to man!

In terms of our models I guess its a question of what one WANTS from the
hobby - a steam powered model isn't better - it's just another aspect that
can add an extra challenge/dimension to the hobby. If your interest is more
the building side then it probably doesn't matter what sort of powerplant
you use. If you tend towards spending as much time as possible sailing the
model then I would venture to suggest that electric is the way to go. If
steam and model egineering fascinates and excites you - well, you can't not
can you??!

All the best

Stuart Badger

[Derek Warner]

Thanks Stuart - we all learn for the experiences of others and I found your text
incredibly interesting - particularly the 80 RPM limitation = negates speed increase,
increases cavitation = water showers and at the same time reduces stability

I had assumed this is all relative to the model in question, but when we consider
she was built to original scale plan dimensions, it suggests that any similar sized
(displacement) model of similar lines and if built to scale will provide similar
results

With Decoy I could use a little (more) licence and show the Saito steam engine from
port & stbd sides so she could be direct paddle shaft drive and have the axis of the
cylinders (or the engine axis) angled down by say 40 degrees which was the case in
Decoy I believe (to get some mass lower down, or chain drive the engine up to the
paddle shaft (similar to your Old Trafford set-up)

I believe on vessels with inclined steam engines, additional blow down valving was required
to expel the condensate which naturally collected at the lowest point - being the underside
of the top of each cylinder head etc

The 3500 no load RPM scared me a little, however as you have mentioned today and in
previous postings, that if the steam can be controlled, low speed & steam go hand in hand

So a combination to consider could be the Saito inclined paddle engine with a Cheddar
boiler & ABC & associated gas firing & control equipment etc

Again your progressive postings on Reliant "on the pond" awaited - regards Derek