# NT but hot



## lotsasteam (Jan 3, 2008)

Pushed myself to dig out my few year old Hit n Miss 12cc Hoppy motor!Painted it John Deere Green installed the piston rings and temporary assembled the unit its a true ready to build kit besides cleaning up some casting flashes everything fits perfect ,the only problem with this kit are the aluminium Flywheels they are to light org 170 gram per wheel ,i need to get a minimum of 400-420 gram weight per wheel to archive the "tick over"typically for a hit n miss! Two choices : get a brass or cast iron ring mounted on the original alu flywheel : alu flywheel is 170 gram brass or iron ring =250 gr makes a total of 420 gram,or 2nd choice ordering a cast bronze flywheel 3 1/2 diameter and get it machined to fit the tapered crank! Here is the problem ,my taig lathe will not work on this size anybody volunteers to do the machining for me?


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## Nick Jr (Jan 2, 2008)

lotsasteam, looks like a robust engine, have you gotten any further? LiG


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## seadawg (Jan 2, 2008)

Pretty cool kit! Who makes it? ( I googled 12cc Hoppy motor and didn't get much back, nothing hit and miss.)


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## lotsasteam (Jan 3, 2008)

Run into a problem,the oil hole in the zylinder sleeve is missing?Fa Rauhut (in Bremen ,DE) website is down ,i called and nobody answered ,so i have to wait till i get any info about the diameter of the hole!

RAUHUT KG
WERNERSTRASSE 39
28203 BREMEN,DE

[email protected]
www.rauhut-kg.de
011 49 4217926513 (complete number call from the US)


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## lotsasteam (Jan 3, 2008)

*Here is one running(not mine*


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## Greg Elmassian (Jan 3, 2008)

That's not like the hit and miss I am used to... where it "hits" a power stroke, then slowly slows down (misses) until it gets going too slow, and then "hits" again...

This one seems to be "hitting" all the time. Maybe it is working hit and miss but at that rpm it sure does not have the "coolness" I am used to.


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## lotsasteam (Jan 3, 2008)

Right it's hit n miss look a like,the coil ,spark plug and points are missing,with a little mods it will work like a real hit n miss!


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## lotsasteam (Jan 3, 2008)

The guy in the video runs rc plane fuel and removed the Hit & Miss linkage partially ,he had some problems running it as a H&M !!
My engine will be a hit & miss like the original only it will run on coleman fuel with an oil mix added !Need to get the flywheel modified and get the ignition parts set up,besides fabricating the linkages ,muffler splash guards and mounting board !


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## Greg Elmassian (Jan 3, 2008)

Which one are you talking about, the one you are building, the one you posted a video of, or the one I posted?

confused.

Greg


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## lotsasteam (Jan 3, 2008)

Here is a how to set the TIMING SAMPLE!


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## Greg Elmassian (Jan 3, 2008)

Hmm... how can a degree wheel read correctly if it is not exactly centered with the axle... it has about a 4 inch offset....

Does not seem it can be accurate... maybe not so much error a few degrees from being "zeroed" but definitely not accurate at all degrees of the crank... 

Greg


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## lotsasteam (Jan 3, 2008)

Got a better solution or just quacking along!


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## Greg Elmassian (Jan 3, 2008)

design a mount so the gauge is coaxial with the crank centerline of course...

quack quack...

think about it...

greg


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## lotsasteam (Jan 3, 2008)

On those older engines the machining was a little bit sloppy in general so a few degrees didn't do much ,so around 1k rpm you hardly could induce valve chatter ,the worst thing happen your exhaust or intake valves where leaking or it wouldn't run at all!


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## lotsasteam (Jan 3, 2008)

Here is the ignition i will be using!
http://www.modelenginemaker.com/index.php/topic,7674.0.html


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## Greg Elmassian (Jan 3, 2008)

I'd start by adding the extra resistors he mentions in the other circuit. One limits the current through the coil, and I would think the spark is hot enough.

The other protects the transistor which is a good idea.

I'm surprised there is no BEMF protection diode in that circuit for the transistor.

Greg


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## lotsasteam (Jan 3, 2008)

Good walk through how a hit & miss works,switching between 4 stroke and hit & miss!


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## Chris Scott (Jan 2, 2008)

Maybe....

STUART MODELS
Tel: +44 01308 456 859
Fax: +44 1308 458 295
Email: [email protected]

http://www.stuartmodels.com/


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## Greg Elmassian (Jan 3, 2008)

Yeah if you read German... seriously!

Could not find one in English?


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## lotsasteam (Jan 3, 2008)

https://www.bengs-modellbau.de/en/


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## lotsasteam (Jan 3, 2008)

https://www.banggood.com/Full-Metal...ift-p-1239802.html?rmmds=buy&cur_warehouse=CN
could not resist!


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## lotsasteam (Jan 3, 2008)

The Banger running


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## Greg Elmassian (Jan 3, 2008)

So you are pleased with the build quality, but it is finicky? What for us prospective buyers is finicky? Tips/suggestions? Also, what does that allen screw adjust?

It did seem to run pretty reliably at high and low speeds.

How long can it run before you need to change the water?

Thanks, Greg


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## lotsasteam (Jan 3, 2008)

still on the slow boat,bear with me ,will test run engine and report here !


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## lotsasteam (Jan 3, 2008)

Received my Hit & Miss engine today via DHL didn't pay for this speed express ,i think its chinese courtesy to send things out ASAP because of the upcoming 14 days of china celebrations!
$259.00 plus free shipping and i spend another 4 Dollar 95 for this receipt to show my wife that i just spend 27.95 on this incredible deal!


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## lotsasteam (Jan 3, 2008)

the Microcsm Hit & Miss is a good running engine,i lubed all the motion parts used a 3.7 volt lipo for the ignition filled up the tank with naphtha (coleman fuel,almost no stink) tested the spark plug for sparks(yes indeed it sparks also it straighten up you facial hair,quite a zap)here it runs (removed the ugly blue fuel tank colour) only minus the crank is not balanced (will turn it down later)


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## Greg Elmassian (Jan 3, 2008)

Are you going to drill holes in the crank counterweight to remove/add weight?

Greg


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## lotsasteam (Jan 3, 2008)

i will machine some material away,first add some steel on the outside (Crank + piston taken out and put on a balancer with weight added on the outside till balance is good,then remove the same amount on the opposite side ,mounting testing filing away till its ok!

On the second run today the ignition crapped out, hall sensor is ok must be the ignition unit,haven't taken apart yet ,gotta get a 1nf/250 volt capacitor ,a 1m ohm resistor ,tlp-42 transistor besides the battery igniter i already have!


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## Greg Elmassian (Jan 3, 2008)

Sorry to hear the ignition crapped out.

So, balancing should get rid of that vibration.

Greg


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## lotsasteam (Jan 3, 2008)

I opened up the ignition module,that's what i found!! Already contacted vender for a replacement,!,Had an idea how to fix it ,the platine is non removable (epoxy cast around the coil) so to get the soldering iron to work i had to cut a window into the housing with a diamond disc,in order not to shorten out the electronics (aluminium grindings i tape the spot inside and carefully cut into the housing soldering was easy ,and after testing i closed the window with tape! Pics attached!


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## Greg Elmassian (Jan 3, 2008)

Not clear, did you replace the transistor only?


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## lotsasteam (Jan 3, 2008)

Used the same one,resolderd properly!


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