RunRyder RC
 4  Topic Subscribe
WATCH
 1 page 822 views POST REPLY
HelicopterEngines Plugs Mufflers Fuel › OS 70 Muffler-It's not out there!
11-12-2005 04:36 AM  12 years agoPost 1
LS1Heli

rrApprentice

Darien, Illinois

My Posts: All  Forum  Topic

After doing tons of reading and research on mufflers for the OS .70 (which I need), I have came to the conclusion that no one really cares about this engine.

For the people out there here are the choices:

- Hatori SB70. I absolutely dispise a two piece muffler. You would spend more time figure out how to mount it then flying. Why some designed a 2 piece I will never know.

- TT PV0205 muffler. Bascially a .50 muffler on a .70 engine but seems to work ok.

- MPII 80/90. An 80/90 muffler that is designed for 80/90 engines that some people still use and swear it works fine

- Mavrikk MVPV205. Nothing more then a cheap version of the Revolution .60 muffler that Heliproz claims is "tuned for the .70". What a bunch of BS! Why the much smaller TT muffler is recomended over this one I have no idea.

- The only choice left. The SAB 70 one piece. Finnaly a one piece muffler. Disadvantage is that it is smaller than it's SB70 counterpart. Only one place carries it and they are out of stock!

Anyone out there turning this into brain surgery like I am?

Raptor 90SE

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 04:51 AM  12 years agoPost 2
ESWLFSE

rrElite Veteran

Liberty Hill, TX

My Posts: All  Forum  Topic

My SB-70 fit on my Raptor 60 like it was made for it. I see no issues with the 2-piece design.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 05:25 AM  12 years agoPost 3
Tyler

rrElite Veteran

Chicagoland area

My Posts: All  Forum  Topic

I use two Hatori SB-15 two piece mufflers. Although they perform well, tune nicely, sound great, they are not worth the hassle of mounting and maintaining them.

By the way, one of these mufflers was used on my OS 70 with superb results. Just had to deal with worn o-rings, broken mounting clamps, broken mounting brackets, loose standoffs, and so on.

I replaced my sb-15 for a zimmerman 80 one piece muffler. It is just as quiet, makes more power, and holds a needle setting better. Most importantly, I don't chase needles and glow plugs when like I did when the o-rings on the two piece sb-15 would start to leak.

Call Ron Lund at Rick's r/c about this muffler, he will know which one it is. I can't recall the model number. You could even ask Ron to look up my invoice for the exact number.

Tyler

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 05:40 AM  12 years agoPost 4
ESWLFSE

rrElite Veteran

Liberty Hill, TX

My Posts: All  Forum  Topic

From what I've read a poorly chosen muffler might allow you to spend more time chasing needles than you would mounting an SB-70.

The stock clamps needed a little spacer between them to fit right. My bolts haven't loosened yet. I have one of the standoffs slightly trimmed and mounted to the top of the skid mount using a long skid screw. You can try that if you end up forced to use the SB-70.

What about just having it welded into a one-piece??

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 05:56 AM  12 years agoPost 5
Tyler

rrElite Veteran

Chicagoland area

My Posts: All  Forum  Topic

Ths sb-15 would tune great, until the o-rings would start to fail. Of course most engines need a little click or two here and there to compensate for the weather, so needlw tweaking isn't out of the question with ANY muffler.

I simply had to learn the hard way to check those blasted o-rings before allowing myself to make drastic needle changes and change expensive glow plugs.

How frustrating is it to show up at the field with a gallon of fresh fuel, and fully charged heli, and then realise the o-rings need replaced. I always had a hard time getting the o-rings exchanged. I saw others fight the bloody install as well. Pinching the second ring is very easy. This is not a do it at the field kind of task, but I often found it needed to be done then and there if I planned to get my stick time in.

Tyler

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 06:11 AM  12 years agoPost 6
ESWLFSE

rrElite Veteran

Liberty Hill, TX

My Posts: All  Forum  Topic

How long would you say the O-rings last in gallons?

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 09:27 AM  12 years agoPost 7
jkelly

rrVeteran

Bedford, PA

My Posts: All  Forum  Topic

I am having good results with the SB-70 and I was fortunate to get a hold of a couple of the machined clamps. They're nice and were easy to install. I suppose a 2 piece is possibly better in a crash, at least that's one reason I know some guys use them. As if crashing the machine isn't bad enough but a broken crank case is the cherry on top. With that said I've crashed a MPII on a 90 and it didn't hurt the case but running the throttle wide open sure can rip the sides clean off a clutch bell and then the conrod explodes.


PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 02:52 PM  12 years agoPost 8
Tyler

rrElite Veteran

Chicagoland area

My Posts: All  Forum  Topic

IF, and I mean a big IF, I can get the muffler to seat correctly over the O-rings without pinching, I have seen the o_rings last as long as 8 gallons or so, maybe even more. I never kept count. If I pinched or stretched an o-ring, they may last as short as one flight. Those o-rings are pricey, too. I ordered viton substitutes to keep the cost down, but I still consumed a dozen sets in one year with two mufflers in service.

I bought the two piece design because of the broken crank case horror stories and pictures. However, after I realized that one of my $145 mufflers was damaged in a minor crash just enough to tweak the header coupler on the muffler side that it would no longer hold a perfect o-ring seal, I decided that the pricey two piece hatoris where more vunurable than an engine case and much less survivable due to their soft, thin, lightweight construction/materials.

Tyler

PM  EMAIL  GALLERY  Attn:RR  Quote
11-12-2005 04:26 PM  12 years agoPost 9
tmonson

rrApprentice

USA

My Posts: All  Forum  Topic

I've used a SB 70 and am currently using a Mavrik 90 sized muffler. I can't tell a difference in performance between the two. Not sure if the Mav 90 is available any more...

PM  EMAIL  Attn:RR  Quote
11-12-2005 11:32 PM  12 years agoPost 10
jkelly

rrVeteran

Bedford, PA

My Posts: All  Forum  Topic

I'm not too sure about the o-rings but mine are holding up pretty well. I put a little oil on them and slip the thing together. I noticed it can bunch up if you aren't careful but so far so good. Not sure how many gallons I have on it but it's not more than 10.

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 01:36 AM  12 years agoPost 11
George Matthews

rrElite Veteran

N.W. Ohio

My Posts: All  Forum  Topic

I have a SAB-7 on my OS 70 and raptor and I think it performs great.

George Matthews

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 05:14 AM  12 years agoPost 12
Nasscar][

rrVeteran

Delaware

My Posts: All  Forum  Topic

I'm using the Maverik 90 size muffler with good success with enya #3 and I run between 15% to 20% Morgan Cool Power.

I know most people says the OS 70 engine comes to life with 30%. I'm having with my setup.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
11-13-2005 01:35 PM  12 years agoPost 13
LS1Heli

rrApprentice

Darien, Illinois

My Posts: All  Forum  Topic

George, SAB7 or 70? I think the 7 is designed for the YS .80. So it works pretty good then?

Raptor 90SE

PM  EMAIL  GALLERY  Attn:RR  Quote
11-13-2005 01:41 PM  12 years agoPost 14
George Matthews

rrElite Veteran

N.W. Ohio

My Posts: All  Forum  Topic

I am looking at the box and it does say "SAB-7 (OS70)"
So the SAB-7 is made for the OS 70.
Yes I am happy with it.

George Matthews

PM  EMAIL  GALLERY  Attn:RR  Quote
11-14-2005 12:58 AM  12 years agoPost 15
LS1Heli

rrApprentice

Darien, Illinois

My Posts: All  Forum  Topic

Well cool..I never new that. Heliproz has that one in stock. Its a one piece right?

Raptor 90SE

PM  EMAIL  GALLERY  Attn:RR  Quote
11-14-2005 01:05 AM  12 years agoPost 16
George Matthews

rrElite Veteran

N.W. Ohio

My Posts: All  Forum  Topic

Yes it is the one piece .

George Matthews

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 822 views POST REPLY
HelicopterEngines Plugs Mufflers Fuel › OS 70 Muffler-It's not out there!
 Print TOPIC  Make Suggestion 

 4  Topic Subscribe

Sunday, January 21 - 12:49 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online