Squint Scale Curtiss Model K Aero I4

[Kim]

The lunar surface looks great!  And it still goes around! What more could you want? 

Kim

[cnr6400]

  She's turning nicely! Noise and smoke can't be too far away!

[Admiral_dk]

Great to see updates here - the paint job has the wanted effect 

Good to see the Pistons go up and down too 

Per     

[RReid]

Thank you guys!

Noise and smoke can't be too far away!

Yeah, and when I get there I hope the noise sounds right and the smoke smells right!

[RReid]

Chipping away at getting final sorting done. Got the cams located and pinned into place and the valve timing (roughly) set. I was about to cut the excess length off the camshaft, then decided to postpone that a little longer. Just in case. If I decide to go with a shop-made distributor, that would be the logical place from which to drive it.

Spark plugs are the next hang up. The plan all along has been to use 10-40 plugs sourced from Steve Huck's miniaturesparkplugs.com. I've used his plugs in my other engines, and the 10-40 size in my Upshur single. Unfortunately I discovered last week that he has had to close that business. Now the options are to make my own or buy the significantly more expensive Rimfires. I think I'll have a go at making them, but will have to gather some materials.

[bent]

The noise it makes already suggests a well tuned/balanced motor, no weird vibrations or clatter.  Yes, no valves on it yet which will add some noise, as will combustion, but looking great so far!
 

[RReid]

Thanks Bent!
I've since repeated that test/run-in with the engine fully assembled, but didn't make a video. Ran it up to ~1500 rpm or so and all was good.

[RReid]

Work has been underway for the past couple of days on a set of  5 10-40 size sparkplugs. These are simply copies of the plug of that size I sourced from Steve Huck for my Upshur single. The first step was to turn the main “bodies” from 1/4” hex steel stock. A die in the tailstock die holder was used to cut the threads.


With the parts screwed into a threaded bushing held in a collet, they were then blind bored from the other end using the set-up shown below and a 1/8” drill followed by an end mill to finish the bore.


The same bushing was then used to hold the parts in the mill vise while three sides of the tip were milled away to leave the familiar L-shaped ground electrode.




Reversing ends again, I did a short counter bore with a #13 drill. This forms a shoulder for the insulator to bear against and a thin-walled section that can be swaged over to hold it.


Making a set of brass washers is a simple step, but one where the parting off can lead to parts escaping, never to be found. I found that this empty “Glide Floss” package made a handy small parts catcher.


Ready for insulators and center electrodes. A sample of Corian to use in making the insulators is due to arrive today, but it hasn't made an appearance yet.

[Kim]

Those are nice looking spark plug parts there, Ron!

Too bad about Steve Huck's spark plugs.  Did he stop making spark plugs completely?  Or did he just stop making the 10-40 ones?  Hope he's doing OK.  Haven't heard from him here in a long time.

Kim

[crueby]

Tiny little sparkers!  Looking great!

[RReid]

Thanks Kim and Chris!

According to Steve, a change in tax law as regards hobby businesses meant that it no longer made sense to sell his spark plugs and he had to shut it down. Other than that I think he's doing just fine.

[Kim]

Thanks, Ron.  I'm sorry that he can't sell his spark plugs anymore.  I know many people really liked them. But I'm glad it doesn't seem that it was for health reasons or anything. That's nice to hear at least.

Kim

[bent]

I think I see where this is going (the spark plugs) but how do you keep the electrode from shorting/sparking against the housing?  Or does the Corian insulator neck down and fill all the way to the business end of the plug?  Hmm, will have to watch and see....
 

[RReid]

I think I see where this is going (the spark plugs) but how do you keep the electrode from shorting/sparking against the housing?  Or does the Corian insulator neck down and fill all the way to the business end of the plug?

Hi Bent. Yes, that's correct. The Corian extends to the end of the threaded portion at the tip.

[Vixen]

Hi Ron,

Nicely proportioned sparkies. Do you intend to swage the body over the Corian insulator, or will you use epoxy?

Mike