DH Gipsy engine 1/4 scale

[hilldweller]

Crazy.

That really puts what you've done into perspective.

What about sparks, is that your biggest challenge ?

[kendo57]

The plans show two dummy magneto's which actually contain a set of points and a rotor / distributor.

If I follow the plans then i would need to connect a coil and battery to make up the ignition but a
better way would be to buy a Hall sensor and run it off one or two magnets rather than points.
Trouble is i am not great with electronics so i need to research the best way of doing it , probably
run a 'lost spark' with two plugs firing at once .

[iansoady]

Lost spark with double ended coils would be easiest then you can trigger off the crankshaft. I assume the crankshaft is single plane ie 2 pistons at TDC at the same time?

[David]

Minimag make set ups for models.

[hilldweller]

Trouble is i am not great with electronics

You have a PM.

[kendo57]

Trouble is i am not great with electronics

You have a PM.

Hi , thanks for that , i have some machining work to do for now but may pick your brains when
i get into designing the ignition unless i find a ready made kit.
I wondered whether i could adapt this https://www.ebay.co.uk/itm/Automatic-Tw ... 1438.l2649

[hilldweller]

a ready made kit.

There's no point in re-inventing the wheel, unless the wheel is mega expensive.

On the face of it that looks a brilliant solution. Size is perfect. Two kits, two hall sensors, one magnet and job done. I think.

[kendo57]

Not touched it since my last post , got tied up with other stuff. Hopefully get on it again soon.

[David]

Please do...its a corker!

[kendo57]

Thought i would update this thread, I won't bang on about my health issues but it has been the reason this got abandoned.
I did forget to take some pictures but nothing exciting.

So all the engine needed was an ignition system, the original engine is fitted with twin magnetos but the model
has dummy magnetos , one housing the contact points the other the rotor arm/distributor.

The contacts are made from Tungsten cut from a Tig welding rod . A small piece was cut off the rod and silver soldered to
a M2 screw and fitted to a brass back plate. Another piece was silver soldered to some spring steel [taken from an old feeler gauge].
The two parts fit together to form the contacts , i hope you can work it out from the pictures.



The contacts are fitted inside the dummy magneto and operated from a simple cam driven from the oil pump.

[kendo57]

The other magneto has the distributor cap fitted, this is turned from Nylon bar and the holes drilled
to take the plug leads. Each lead is held in place by a brass screw which also forms the contacts.
The centre screw is missing in the picture as there is no coil lead fitted yet.
The spark is distributed by the rotor arm driven from the other side of the oil pump, this is just made
from nylon with a brass contact glued across it.

[kendo57]

I was going to test the ignition and try and start the engine but unfortunately the coil i had in stock
is a 'single wire' coil which i think is only used on bikes without a battery and AC generator.
I will have to see if i can borrow a coil or just buy a cheap one off EBay.

[Skub]

A thing of beauty.

I hope you are feeling better man.

[crust]

So impressed, a work of art, it's beautiful.

Thanks for the update.

[Zimbo]

Can't wait to see it run!

[MingtheMerciless]

[Count Steer]

Missed all of this first time around and have just sat here and gone slowly, pausing to applaud, through the whole thread. Awesome, just awesome.

I have a buyer should you ever want to make another pair of spark plug ear rings too.

PS What happened to hilldweller? He stopped logging in about the time this thread stopped. (He'll be nearly 80 now).

[Eclipse]

Hello kendo57, lovely work as always.

Do you know anywhere that sells Cast kits and plans for IC engines ?
I am currently making a Stuart Progress from castings.

[kendo57]

Hello kendo57, lovely work as always.

Do you know anywhere that sells Cast kits and plans for IC engines ?
I am currently making a Stuart Progress from castings.

Its a while since I have been to a Model Engineer show so a bit out of touch.
I am guessing you have used google and found Reeves Engineering and Engineers Emporium .
I was lucky and got mine through a private seller on Homeworkshop.org.uk but you do sometimes
see people selling on forums, you have to be quick though.
I thought about doing a Stuart engine but they seem to have really gone up in price these days.

[Eclipse]

I didn't know about Reeves so thank you for that.
Stuart Engine casting kits have slowly been creeping up in price,
the progress castings came to £146.20 but they do sell each casting
separately incase you make a mistake.