Hoglet Ignition

[seadragonfoundry]

I have been progressing well with my pair of Hoglets. Have just finished cutting the cams, I used the method described in MEB Issue 7. To obtain the angular separation between the lobes, I graduated the baseplate on which the 3 jaw chuck is attached. The Stressproof steel 1144 was obtained from Speedy Metals, it is a dream to machine.

A question please, for those who have gone before me. What did you use or where did you purchase your ignition system from?
I notice on engines shown on YouTube, what appears to be a cylindrical coil mounted above the kick start mechanism and the plans clearly allow for this but no mention is made of the ignition itself. All help gratefully received.

 

[Jasonb]

I got mine from SS Machine though have yet to hook it up, they do one specifically for the Hoglet. I also has nice small silicone wires and plug caps not the thick braided cable and metal caps like the Rxcell ones. Got to me in the UK in less than a week and there was no duty to pay

Towards the bottom of the order page

http://www.cncengines.com/orderpage.html

J

PS its a good method for doing the cams, first time I had used it on this engine

 

[crankshafter]

Hi seadragon.
I got my ignition from Roy Scholl. google SS machine and you vill find it.
What you see abowe the crankmechanism on the youtube videos is the coil from Jerry Howels ignitionsystem. I'm not sure if you can get thous anymore.
Nice work on the camshaft.I make my camshaft the same way you did. but I made it whit 4 lobes. Plans for the 4lobes did I get from Clerance Elias.
Best reg.
CS

 

[Jasonb]

Minimag do a small 2 outlet coil similar to the one you have seen - Novus2

http://www.minimagneto.co.uk/Products.php

This would be used with hall sensor and ignition circuit board/controller

 

[seadragonfoundry]

Thanks for your help. I have bought from SS machine before and never noticed the Hoglet system, thanks Jason. I will email them for some photos.It was first time for me machining the cams by this method also, I will do it better next time! For Crankshafter, I would be very interested to obtain details of the 4 lobe camshaft, can I PM you for details?Thanks
Graeme

 

[Jasonb]

If you do need any photos of the Ignition PM me your e-mail.

J

 

[BronxFigs]

PLEASE.....don't laugh, or, get pissed-off by my ignorant question(s):

Can the "Hoglett" be made to run on glow-plugs? And, if yes, would the glow plugs eliminate all the electronic doo-dads needed for spark ignition? I should've done some reading before posting this question, but I feel lazy today. Not too familiar with glow engines and ignition requirements. Are glow engines more simple than sparkers....ignition-wise?

Frank

 

[seadragonfoundry]

Thanks for your question which I really can't answer. I have never had anything to do with glow plugs but I see your point. Perhaps someone with more knowledge and experience can answer this one.

 

[Putt-Rite]

PLEASE.....don't laugh, or, get pissed-off by my ignorant question(s):

Can the "Hoglett" be made to run on glow-plugs? And, if yes, would the glow plugs eliminate all the electronic doo-dads needed for spark ignition? I should've done some reading before posting this question, but I feel lazy today. Not too familiar with glow engines and ignition requirements. Are glow engines more simple than sparkers....ignition-wise?

Frank

Glow plug engines are a kind of diesel AFAIK. You heat up the glow element in the plug with a battery. It looks like sort of a regular spark plug, but instead of a spark gap, there is a tiny coil of wire that glows. Once you start the motor, you disconnect the battery and the motor continues to run. I think I get your point tho, ignition systems are like a black art to some of us (like me).

 

[Jasonb]

Some model 4-stroke engines are run with glow plugs but I've never tried it.

The Whittle V8 is one that springs to mind
http://www.hemingwaykits.com/acatalog/The_V8_Aero_Engine___Eric_Whittle.html

 

[camm-1]

It work but you need Hot plugs that glows easyer and good compression.
You can also let the power be on the plugs then running if you need.
Dont think it is a good idea with orings on the pistons especially not if you have
Some nitro mix.
Ove

 

[BronxFigs]

Thanks for some interesting answers. So, compression ratio, fuel, type of glow-plug matter.

Interesting implications, judging by some of the posted answers.


Frank



EDIT: An interesting link was provided, and Hemingway shows a Whittle - "Aero-Eight" engine.

Question: Do multi-cylinder GLOW-PLUG engines need to use a distributor to "fire" the glow plugs? Since they fire like a diesel, is it the correctly timed spike in compression-ratio that fires the correct cylinders?

Who needs to make/use distributors, gears, wires, points, etc...if glow-plugs eliminate the need for all these complications?

 

[Jasonb]

I think the Whittle keeps the power to the plugs all the time so they are constantly glowing.

 

[gbritnell]

It's not that most any engine couldn't be made to run on glow plugs and glow fuel but there are issues. The major issue is that with a slow running engine like the Hoglet the glow plug would never stay hot between firing cycles so this would necessitate a glow driver box to keep them hot. Glow plugs rely on a catalytic reaction of the fuel and the hot wire of the glow plug to stay hot. If the plug gets too cold from fuel mixture or slow operation then it will stop glowing. Now you're switching from one type of ignition box to another. The second thing is that the compression needs to be spot on. Where the normal I.C. engine can get by with a little less compression the glow engine relies on it for operation so tolerances and lubrication would have to be much better. Another issue is what glow plug should be used? Just like spark plugs they come it many different heat ranges that suit fuel mixtures, engine rpm etc.
Personally I think a spark ignition for our small engines is the easiest route to go.
gbritnell

 

[BronxFigs]

Thank-you for helping me with my original questions. Not being familiar with how these engines operate, I had no idea that they could be temperamental, unless all operational parameters are 'spot-on" as suggested by Mr. Britnell, et al.

So....back to square one. Sparkers are more versatile, and are easier to adapt to use as ignition for model engines.

What about Peizo-ignition systems? I hardly ever see engines using this system.


Frank

 

[deverett]

So....back to square one. Sparkers are more versatile, and are easier to adapt to use as ignition for model engines.

What about Peizo-ignition systems? I hardly ever see engines using this system.

Frank

For a description, have a look at Jan Ridders' site http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_crcuit_frameset.htm

There is an English language version if you click the button at the top of the page.

He also has an extensive range of very interesting model engines.

Dave
The Emerald Isle

 

[BronxFigs]

deverett:

Just read the link you provided with additional information. I will now do some more reading. Thank-you for all the help.


Frank



EDIT: Just read the information on the J. Ridde site. Great information about ignition system designs, both pro, and con. Much obliged.

F

 

[kadora]

Hello Frank
Have a look on this
http://www.hobbyking.com/hobbyking/store/__8868__Replacement_Twin_CDI_for_CM_6_Spark_plug.html

i think this is the simplest way to fire your Hoglet with spark plugs.

I am going to try to start my we tween /see avatar/ this week
on glow plugs i prefer this system because glow ignition needs only 1.5 V
battery.
Cons You have to find proper fuel mixture /0%-20% of nitro to methyl/
and suitable plug . On the market is possible to buy super cold,
cold,medium, hot and four stroke glow plugs.
Then you need a patience to find the best plug and fuel mixture for your compression ratio and carburetor.
Basic rule for High compression 0% nitro - cold plug
Low compression 20% nitro - hot plug
Kadora

 

[tornitore45]

Hi seadragon.
I got my ignition from Roy Scholl.

Same for my boxer engine. I have not used it yet but plan to use the wasted spark method which suites a a boxer configuration whell.
May not work for the Hogles since is not phase exactly 180* of camshaft.