ys sr dual plug head

[betta2500]

here we go.

[betta2500]

other pic.

[Jafa]

The machining is excellent - well done

[betta2500]

thanks.

[Pulento]

Just got mine.

Beautiful head. I installed on my T700. Do I need to drill another hole or elongate the stock hole of the fan shroud to reach the angled plug ?

[MaSt0RaS]

Originally Posted by Pulento

Just got mine.

Beautiful head. I installed on my T700. Do I need to drill another hole or elongate the stock hole of the fan shroud to reach the angled plug ?

MMmm a good question... probably yes.... If one plug is damaged can the engine work without problems?!

[betta2500]

yes you have to make a little cut,cut the hole all the way to the bottom that's what i did on mine.

[billiano]

I just got mine
I am waiting to get it in my hands.Very nice service from betta2500

P.S:The angled plug should face downwards?

[betta2500]

Always facing down.

[betta2500]

Anyone interested?

[Pulento]

Had time today to put 6 flights and the difference in power and smothness is noticeable. Definitely worth the money.

It seems to run cooler also, I´m just measuring in the same spot as with the stock head. Actually the head has bigger fins, about 3 to 4mm longer.

The only downside is the even cutting the plug hole all they way to the bottom on the shroud is really hard to remove the angled plug. I was able to grab it with my flexible Vario wrench, but didn´t tried to remove it since putting it must be harder

[fixnfly70]

Originally Posted by betta2500

Always facing down.

I have a 91ST that is in rebuild state and would like to know:

1. Clarify "facing down" upon install - angled hole @ bottom (or rear of motor)?
2. shipping to longview tx, 75601 and instructions for payment.......80 + sh sounds good to me and looks better! very nice machining!

Thanks betta!


Also - anyone with a used hatori SB-16FH you would like to sell?? am searching for one......thanks in advance

[fixnfly70]

Originally Posted by Jafa

Cars and various engines use multiple spark plugs to get the flame front to travel sideways faster and then start pushing the piston down

You can get a smoother running engine

You can use two different heat ranges - makes the idle really smooth on one plug and the stunt mode really smooth on the other plug

Some argue that it's also a bit of a safety against a flame out due to loosing the plug in flight

Exactly!

[Real] piston airplane and heli engines (made by Lycoming or Contenintal) all use dual plug for many reasons - some required by law:

1. Redundnacy, as each plug is powered by totally seperate magneto or other Hi Volt coil and wire. (FAA reg requirement too)
2. Safety - lose one plug/wire- you do not loose that cylinder.
3. Safety - loose 1 mag/coil/switch you loose 1 plug in each cyl - but not whole motor- engine out........engine will however loose 25 - 100 RPM becuase of the loss of effeciency of combustion. Each mag/coil fires 1 plug in each cyl.
4. smoother operation when both mags and all plugs firing....the little 4 cylinder 360 cu/inch motors up to the Pratt&Whitney radial R4360 (4 rows of 9 cyls = 36 cyls and 72 plugs - 4360 cu/in) all use dual ignition systems and dual plugs.....only a few types of engines stagger timing on the plugs - most fire both@ same time @ 18 - 24 deg Before Top Center.
5. This dual system is tested prior to every flight - by shutting off one mag/coil while engine running @ around 75% of full power....the acceptable "mag drop" is 25 - 100 or so RPM but a smooth drop........usually more of a drop or a rough (backfire) with either mag coil off indicates a "dead cyl" on that mag and flight should not be made.

A dyno would be required to verify any benefit of dual plug install on a .91 cu in 2 stroker @ 16000 revs, but my experience of 20 years working on airplanes for a living and working with r/c 2 strokes much longer than that I'd say there is very likely some benefit from increased combustion effenciency alone and the safety of dual plug.........Heck I used to have a dual cyl Saito FA-300T-TDP 4 stroke and it was dual carb AND dual plug.....one easily could tell when at low idle one set of plugs dropped out and when they came back online on throttle up.....I even used a remote glow unit switched to come on just above low idle to keep the aft plugs lit for smooooooth cout the revs looooowww idle.

I am buying one to see/test and report on

[betta2500]

ttt

[Pulento]

Betta,

Do you have in your hands the new YS91SR-3DS ? I'm waiting mine, let us know when you get your heads for this new baby

[betta2500]

I sure will.
Thanks.

[jake28]

Looks like your heads are really coming along beta. I new you had an awesome product my FBL 700 loooves it!
I need to get one of the newer ones with the longer fins.

[betta2500]

sure man,any time.

thanks.

[betta2500]

still have a few.

[Pulento]

Now I have about a gallon on my YS91SR-3DS with Betta's head and is running great, a bit more power on mid and even smother than the stock head.

Running with two OS8 glow plugs. Very happy with this mod