Hi everyone,

I moved the websites to a other server and hope the website are avalible.
If there are problems, missing pics or broken links, please let me know.
For the moment I can't exame the logfiles of this server and don't know if everything is working like it have todo.

http://www.modelbouw.gompy.net
http://modelbouw.gompy.net
http://www.electronics.gompy.net
http://electronics.gompy.net

I make a short break to load my brains and do something differend.
I make my first small electric brushless airboat 24x48cm.



Unfortionaly the snow is gone, but maybe we get befor summer still some.
On water it's also big fun, but snow is funfactor 200% with this boats.
The big 50ccm airboat have some damage and need to repair.
This little boat is made in 2 days, so we make a new one if this one is broken.

Maybe some-one can help me, I need a fiber propellor for the airboat.
It's hard to get one into the Netherlands of this format 20x8 or 20x10
I need a address or maybe somebody can buy it for me (I pay back !!)

TIA

how about a 18x8 three blade prop?? that is what i am using on a 43cc homelight chainesaw motor on air boat

Thats 4" less......I don't know how this lookslike into the cage.
The cage is made for a 22" propellor, now using a 22x10



I think a tiny propellor is given the boat a Mikey Mouse look (?)
All the pics of the boat http://www.modelbouw.gompy.net/airboat/index.htm

Hi Rob, check here, they have what you want. If they do not ship to you ,I will get it and send it to you.



http://www.troybuiltmodels.com/cgi-b...p;perpage=5000

or
http://www.chiefaircraft.com/rcmsec/...XOARProps.html


Adrian

This prop is a little to big for the cage, I've only 1/2" on the tip of the prop befor it hit the cage.

@ i7x58,

They will send the props to Holland but it cost to much, almost twice the cost of the prop.
Handling, shipping, pakkage, tax, aso.
Others notice me for Hobbyking but I can't find the right size.

(I can't resize the pics....)

Hi,

<span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">"Houston, we've had a problem"</span></span>

i can build nearly everything of any metal.
But silicium is a terrible job for me :-(

(my last experience was to discharge a capacity of 0,5F / 200V within 0,1 second :-( not planned - sure ! )

is here anyone who speaks or write german and can explain it to me ?
- i've read the thread more than one time
- i've downloaded every file from Gompys homepage (BTW: your name gompy - is there any context to a cafe in Nimwegen ? )

but i don't  get a true light :-(

i need 10 of this CDIs for this engine:



i need a little bit of support by "what i need" and "absolute NoGo" :-)

Frank

That is a good looking engine, what are the specs? and from where the plans.
You may not need 10 cdi units.
You need a system that will have 5 coils, and use waiste spark. 2 sensors, one on the crank for timing and one on camshaft to start fire at cylinder #1 and then divide ...etc.
Rob, Charlie, John and the other guys may know how to do that....I dont, I just have the idea.

Thank You
A

A CDI can handle more then 40,000 rpm, thats why race-engines use them.
Your engine is a 10 cilinder 4 stroke, this means you need for 8,000 rpm 4,000 ignitions.
The problem will be, the cilinder need at the right time a ignition.
Normaly this will do with a mechanic distibutor, the same you can do.
A ax with 10 magnets, 10 hallsensors and the electronics can do the job.[1]
You need 10 sparkcoils and 10 time the electronics for the HV-ignition part.

10x http://www.electronics.gompy.net/cdiscoot/index.html
One big 12 Volt HV-ocsilator (200-300 Volt) can feed the 10 ignitions.

[1]You can do the same with one magnet / opto and a disk.
With a shift register IC you count up to the ignition for the next cilinder, but this itn't easy todo.
First rotation of the engine is lost, this is a reset rotation to let the electronics know the first cilinder is ready to ignite.

BTW-1, if I'll build this engine I'll use 10x opto's and a disk.
BTW-2, you need a distributor 2:1 (two rotation engine / one rotation ignitiondisk)
BTW-3, the idea of I7x58 is also possible todo with the 5 ignitions.
BTW-4, I don't think you must use a advange CDI but one without it.

Hi Rob,


i would like to use 12,000 rpm max - so a single ingnition is not sufficient

thats what i'm thinking about :-)

oh - thats a detail what i'm not able to calculate.
but the HV-oszillator isn't very difficult i think - also 10 times


your explanation about one sensor i understand - but:

sounds ok :-)

i can use the camscraft - but ... (see down)

i'ld like to use it on one reason:
my idea is to run the engine on very low speed also - lets say 500 rpm

<span lang="en" id="result_box" class="short_text"><span title="Zur Anzeige alternativer &Uuml;bersetzungen klicken" class="hps">if I</span> <span title="Zur Anzeige alternativer &Uuml;bersetzungen klicken" class="hps">do not care</span> <span title="Zur Anzeige alternativer &Uuml;bersetzungen klicken" class="hps">to low</span> <span title="Zur Anzeige alternativer &Uuml;bersetzungen klicken" class="hps">speed i can also build a glow ignition engine :-)</span></span>


so - what i thougt to do / have planned in my ideas:
i use 2 distributor-cases at the end of 2 cams - half rpm of engine
every one has 5 optos or hall sensors and a disk with one slot oder one magnet - only a detail :-)
every spark got own coil

the distributors have a diameter of 40mm - so it should be possible to manufacture it with sufficient precision for ignition time of every cylinder.

your posted link:

the input for the schematic was "pickup coil"
means: a magnet rotating and every ignition got an own coil ?

the idea of i7x58 is also possible - of course.
Early 2 cyl bikes use it WIMRE.
But is the energy high enough to produce 2 sparks ?

I'll use a compression of 8:1 or 9:1 - not very high.
Is the spark able to penetrate the compressed mixture when 2 sparks are served by one coil ?

Frank

Hi Rob...
For the French 2CV timer board, is there a substitute for the SKP15N60 IGBT transistor? Very difficult to buy just one here in the U.S.
Everywhere I look, minimum order is 500 pieces!
I have it built without adding the IGBT and 3.9 volt zener, and testing it, the LED's come on as they are supposed to. As I see it operate, it's a TCI and not a CDI. If I could pick a source for the output pulse to link it to a CDI, I would try to convert it..but as it is programmed, only TCI operation is possible. It's not like the universal timer board we have with the 2 sets of software for both TCI and CDI. Unless someone writes a CDI hex file for it??

John

Frank,

What are the specs of this engine?
total CC, bore and stroke?
Are you sure you can run this baby that high? 12000RPM for a v....kind of high.Is this a race type engine?
If your stroke is less then bore....may be able but still ...
Race engines uses high bore and short stroke and develop the HP trough high RPM's do to less inertia, engine can jump quick on RPM's...for fast acceleration...Formula 1, Indy etc.
If your stroke is higher then the bore...do not even think about, they will go up 4500-5000 RPM's and will have a good tork on mid range.
I am ... cooking a V12 engine(merlin engine for more than a year now) and this will not go more that 4.500 RPM's (19mm bore-21.1 stroke)
Ignition and fuel injection will be a real chalange. I am good at mechanics but I s...@ electronics. I have Ideas but I can not make them .

Concerning if will be enough energy for 2 sparks with one coil...YES, it will work, it has been done,I seen it working.

Rob,Guys, I have an Idea for a fuel injection,I will throw it out...Based on the same CDI timing board idea; On the camshaft one sensor to know when #1 is, then based on RPM's to calculate the equal timing for the rest and the mini injectors just to pulse,open and close. Then to have a TPS(throttle position sensor)to know where throttle is. When Throttle opens to increase the fuel pump ...output and put more fuel out trough injectors.I
pump can be electrical and increase the RPM on this , or mechanical with high pressure/volume and for this to open/close a valve . Couple sensors may be need it, fuel preesure and intake presure, nice will be to monitor the temp of the exhoust. Just an Idea...can this be done?

Adrian

John,

Can you post a link to this french timer board?

Specail for Frank in German http://www.mini-cooper-clubman.de/html/cdi.html

BTW, normaly a multi-cilinder engine makes less rpm not more.
I think you need 12.000 sparks / min, the engine crank rotates with 2,400 rpm.

@Charlie http://www.electronics.gompy.net/tci-2cv/index.html

@John, I use this IGBT http://www.google.nl/search?sourceid...L404&q=g4bc30s

@Adrian, we working on a multi cilinder ignition with multi spark.
The link I given Frank looks like wat we have for the HV-part.
Now we working at the distribution for multi cilinders.
BUT, no-one of us have a 4 stroke engine at home to test IRL......we aren't Ferrari.
We can only make the electronics, test on the bench and hope it will work if someone put it in his/het car.

Adrian,

bore 24mm
stroke 22mm
total 100ccm

cylinder angle 72°
valve angle 60°


piston and rod are very light (12 gramm / 7 gramm)


i think 12.000 rpm are possible :-)

the engine should look like a formula one engine :-)

your injection sounds interesting - but such small valves ... oh my dear ...

next month i will order the parts for 5 or 10 CDIs - depending on the next inputs from here.
optical pickup or hall also ...

the distributors place is back side of the heads and connected to the camscraft



Frank

Thanks Rob. What is the purpose of the "Red" switch? Is it 5 position?

At the last page of the PDF or webpage there is a table.
With the switch you can set the advange ~+/- 5 degrees.
BTW, the switch is a BCD-switch with 8 (10) positions.

Hi Rob,

I see what it is. IT sets the Inital advance from .7 degrees to 4.9 degrees depending in the encoder position.

Rob..
What coil would you reccomend for the French 2cv TCI board? A standard CDI type coil has too low resistance to function correctly with a typical value of 3 to 4 ohms or less...making the system draw a huge amount of current, reducing efficiency. I have a rather large coil I used in testing that was designed for ignition systems with points. It typically has 5 ohms of resistance and functions as expected, but weighs almost a pound!

John

Charlie..
If you fina BCD switch that works, let us know the part number..

John

@John, I use a 6 Volt (12 Volt is smaller) mopped / bike coil.

John,

Any of these will work.

http://www.mouser.com/ProductDetail/...Wkh%2fSaW1M%3d

http://www.mouser.com/ProductDetail/...NQQz42ECcDY%3d

http://www.mouser.com/ProductDetail/...zMAfzaKA%3d%3d

Also you probably know this its not for CD ignition.

You need 16 positions Charlie, the one you sellect are 10.

http://nl.farnell.com/jsp/search/bro...atchallpartial

The one I selected are 4. so each pole has 2 positions. so that is 16 positions. you have to understand binary. 4 to the power of 2 = 16

Thoose are 8 position switches Charlie.

This is wat you need http://www.farnell.com/datasheets/105777.pdf