YS91ST/Extreme: wich muffler and gearing

[Knud Pedersen DENMARK]

Got my new YS91ST for replace of my OS91PS/MPII.

I´m strongly considering to by a Hatori Muffler:
The Hatori #998 or the SB16FH.

My combo is a Fury Extreme with 8.18:1, and on wildcat10% nitro.

Anybody have any experience regarding:
- gearing and 10%nitro on these two muffler?
- Rotor RPM 1800 (8.18:1)?
- the floating head (Now clamp) is that reliable?

[DavidH]

The FH muffler is reliable. There is many pilots I see using the muffler here in the States with no problems.

If your wanting to turn 1800 rpm. Then 8.18 will put the motor right in the middle on the power band. 14.7K rpm on the engine.

I have not used 10% nitro,but I have used 15%. The motor runs fine, just noticed the power is down some compared to the 30%.

David

[Knud Pedersen DENMARK]

DavidH

Any experience with the #998?

The SB16FH, does it fir the Extreme without any modifications (ex. canopy)

Should I go for the SB16FH (have to ordre it in USA.......)

:?:

[DavidH]

The canopy will have to be notched very little for the front of the muffler to clear it.

The SB mufflers are made to Hatori USA specifications. The baffling may be a little different than the 998. But other than that both mufflers are virtually identical from what I have seen. I can't get to Hatori Japan website now to look at the 998. But I believe I remember it being floating head design also.

David

[Knud Pedersen DENMARK]

Hi DavidH

Your right – the #998 is with floating head.
But it is different in size:

998:
The 998 is ~251mm from front to rear.
Inlet is 76mm from the front, and from inlet to the rear 175mm.
Diameter is 45mm

SB16FH
From inlet to for end 76mm
From inlet to back end 175mm
Total length 251

Should I pick the SB16FH – (with my 8:18 / 1800 rpm?)
Or the 998 or sb16 without FH....

[NolanManley]

I know a few who don't like the floating head. They fear engine damage in a crash. The SB16 Todd Bennett pipe was developed specifically for the YS engine. They are quiet and the engine runs very good. The SB16FH will run as good as the SB16TB pipe, just different mounting. Your choice is what matters. ;)


BTW, there is a Hatori floating flange pipe being developed for the OS 91c pumped engines (non viper) right now. Saw it at Vegas. Power and sound was very nice.

[Knud Pedersen DENMARK]

NolanManley,

As far as I now, the SB16FH is with Floating head (?) – and it´s a "Todd Bennett" (??)

[DavidH]

Knud,
The SB17 FH will be out soon. This is the muffler that is suppose to be for the OS 91. Eric Larson has one and it performs well on his model.
I have seen a couple models crash with the FH header on them. The FH performed as advertised and the muffler popped off with no damage to engine or muffler.

SB 16 aka Todd Bennett Special
SB16-FH aka Todd Bennett Special Floating head

Here is the email addy for Hatori USA. They can answer any of your questions about the SB mufflers that are imported by them.
hatoriusa@aol.com


David

[WillJames]

Eric's machine was LAYING DOWN the power at Clint's Birthday FF. Was he flying the SB-17 then David? If so, I was wondering. :shock:

[NolanManley]

As far as I now, the SB16FH is with Floating head (?) – and it´s a "Todd Bennett" (??)

Knud, Please don't confuse what I'm saying. There was a SB-16 TB special well before the newer SB-16FH.... Which only had the engine mount changed.

;)

[NolanManley]

UUhhhh Like David said! :D

[3DME]

Hello

Mabey a picture or two will help.

Mike

[Knud Pedersen DENMARK]

FYI

I have now been flying about 20-30tanks with the Hatori SB16FH on my YS91ST/Fury/Revlock/gearing8:18/ 1800 Rpm.
I think it is good:

- low noise (Lower then the MPII) :D

- Fit good, no visibly sign of vibrations :D

- performance: ?? can´t tell because I´m no “Engine-tuning-Expert” and no heavy 3D flyer. :(
But the engine almost maintain the RPM at full pitch (>10°). :D

I have broke on off the O-ring inside the floating head – I think it happen when I assembled the muffler :oops: – next time I better use some grease / oil on O-rings

:mrgreen: