Glowgeek

Not that rich Jim, at least not at full throttle. It is interesting however where we can see a leaner mixture firing in the squish zone where fuel is forced inward toward the center of the piston.

Glowgeek

Oh wait, that's a flat piece of lexan, no squish zone! Maybe the cylinder wall heat is helping to combust the fuel better at the perimeter.

Glowgeek

Ok, I read over my last few posts and I sound like a horse's patoot. Sorry guys, I'm having a lot of back pain right now.

On a sweeter note I'm being sent an early high compression 80 for repair. How high of nitro can I safely run with glow ignition?

Jesse Open

It's all about flame propagation, the flame front The fuel/air at that point is pretty well homogenous .
(Seems to me)

Just as with a torch flame, A range of stages of combustion; IE , the flame front.

Hobbsy

My Feedback: (102)

I have run mine on 5% to 15% with not much noticeable difference. Some say the needle range is narrower on the lower %, but the peak is still the peak. In my book, the 5% always has a softer smoother idle.

Glowgeek

Thanks Dave, good to know.

Glowgeek

Weird, I thought I posted my intial test run info for the 125 but can't find it anywhere. After running a few tanks of fuel rich to break in new parts:

Saito FA-125
15% Nitro/17.5% Oil
Temp 68°f
Humidity 60%
APC 16x6
9170 rpm peak
1700-1750 idle
2.183 hp (calculated)
15.92 static thrust (calculated)

Hobbsy

My Feedback: (102)

Thanks Lonnie, here are four four stroke plugs, from left to right, Taipan 4c special, Glo-Devil 4c for Enya and Saito, Fox Miracle and then OS-f. The Fox has the longest reach, the OS-f is way short on threads.

Glowgeek

Looks like the os-f has 5 threads instead of 6. I wonder how many threads are in my saito heads. Hmmm

I have no fox plugs. Can you measure the fox miracle and os-f from the nose to the seating shoulder for me?

Hobbsy

My Feedback: (102)

The Saito's probably have 7 threads in the head if you add one for the gasket space, the OS-f loses a thread to the gasket, so it engages only four.

WMB

My Feedback: (1)

Hi all, haven't been here in a bit. Haven't flown in a few years now. There was some discussion on 4 Stars awhile back, what a good flyer. My 40 size was bouncy on landing, moving the CG back and doing 100's of touch and goes took care of that. I too did bend the stock landing gear many times and went with something taller for more prop clearance with a 13" prop.
My favorite engine for this plane was the Saito 65, soooo smooooth. Lots of power, good idle, good transition, runs in any orientation. Using an APC 13x6. A little on the porky side though.
Other Saitos fit to this plane:
Saito 82- Over the top power
Saito 45, old style- a little boring, no spring on throttle barrel let the low speed needle drift in and out a little effecting idle quality, aerobatics limited. Had 2 of those.
2 strokes used :
Thunder Tiger 46- very mild, my first engine, not an excess of power. I may have broken it in wrong.
Super Tiger G51- another favorite, smooth, perfect power, good idle and transition. APC 11x5 prop. Messy muffler, oil everywhere.
OS55AX- Incredible engine in every way. APC12x5 prop. Uplines fast and forever. Rarely flew at full throttle other than uplines.
I think the perfect engine for the 4*40 would be the Saito 62. I do have a Sig Something Extra kit, it will get a 62 if I ever build it.
MikeB

Glowgeek

Thanks MikeB, good real life info on the 4*40.

erieqc

In comparison what would a ys-fz53 be to a Saito power wise. I’m asking because most everyone comments that the ys engines are better power wise.

Jesse Open

Darn close to s 72 Saito but iirc a bit lighter with muffler.
Idle is excellent, steady and reliable. Transition is where the YS really shines. You can mount the fuel tank at the cg and have no cg shift during the flight. Not at all sensitive to fuel tank size. No muffler pressure needed and no vent hose .

Otherwise very similar.

Glowgeek

The YS FZ53 at 493g w/muffler is lighter than the FA65 and 80 but heavier than the FA72 and 82.

They are said to make monster power for their size and the YS63 weighs virtually the same as the 53. If I were to get a YS in that size range it would be the 63.

Good to know the tank can go on the cog, I didn't know that but it makes perfect sense. Thanks.

Hobbsy

My Feedback: (102)

Lonnie, found a 4" piece of exactly 5 mm flat bar, I drilled and tapped it for 1.4 x 32 glow plug threads, the Glo-Devil comes exactly flush, the Taipan just shy of flush, the Fox Miracle about 3/32" proud of flush, the OS-f about 5/64" of proud. the 5 mm bar almost exactly replicates the glow plug threads in the Saito head.
The picture doesn't sh

I am going to try for a better picture.
ow that very well.


Better

Glowgeek

Cool experiment Dave, thanks. I had no idea the Fox-M plug was longer than the OS-f. I wish they were still readily available. I've heard varying reports on the difference in temp range between the two but nothing that can be substantiated.

erieqc

Ok here are a few more questions because I don’t know and hopefully one of you will. Being it ys or Saito could a guy use a os g5 plug any run that on methanol?

Glowgeek

I can't answer that question but I have a question. Why run a gas/glow plug when a methanol/glow plug works so well with methanol?

the Wasp

My Feedback: (1)

hey Lonnie, how about a 4st Wonder Plug LOL
https://www.mecoa.biz/shopexd.asp?id=1694

see K&B and new Fox plugs here, but no Miracle Plug.
K&B and FOX GLOW PLUGS

Jim

Hyjinx

Because tinkering is inate to the human while being.
And the ignition module manufacturers appreciate our financial support.

FlyerInOKC

My Feedback: (6)

Its like building from a kit or plans, I don't know any experience builder who builds the airplane exactly as designed! Heck, I think scratch builders are even worse at making changes midstream.

Hyjinx

Innovation creates the future. Adaptation oils the bearings.

erieqc

I was just wondering because I can buy meth for $2.00 a gallon and I didn’t know if I have to mix any nitro with it or just mix it up the same as a spark ignition. If I can could I use a os7 plug or is there a better plug to use. I appreciate all the help and knowledge you guys can share.

FlyerInOKC

My Feedback: (6)

The biggest factor is the purity of the methanol (water free)and getting the correct amount and type or types of oil in it. The amount of Nitro will vary depending on the engine. You get some of the big glow engines like my old Super Tigre 3000 it doesn't really need Nitro but you go down in engine size and Nitro becomes more necessary.