News:



  • March 28, 2024, 09:43:10 AM

Login with username, password and session length

Author Topic: Tongue Mufflers for ST.51s  (Read 890 times)

Online Dan McEntee

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6824
Tongue Mufflers for ST.51s
« on: May 12, 2022, 02:44:38 PM »
   When I got my first ST.51 way back in 1994, I tried to use tongue mufflers without much success. I got a nice, light tube muffler from Tom Lay and been pretty much using that style ever since. Some where along the way I have see photos of guys that actually found a use for the hideous muffler that came with the engine, or at least the manifold for the muffler, and made a tongue muffler out of it. I have pretty much sold off or given away most that I had because the local R/C clubs require those for the club R/C pylon racers using ST.40s, which uses the same muffler. I have repaired the broken ears and such for several guys here, and have accumulated some other broken manifolds that i am going to repair and then make them tongue mufflers just to try. Is there a favorite style or pattern that anyone else might be using that works the best?? Just use holes, or maybe slots cut into the tube. Any information to share out there?
   Thanks in advance,
    Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Air Ministry .

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 4978
Re: Tongue Mufflers for ST.51s
« Reply #1 on: May 12, 2022, 11:09:45 PM »
The ' BIG ART ' toungue mufflers , are Ex. Dubro Exhaust Extension ( stack ) material .

HERE is a rip off , but bigger ( LONGER ) AS its a RINGED ENGINE . And I dont like lawnmower mufflers ( weedeater etc ) direct on the port , so we try to let it all out ! .  :-X





You can see where sombodys laid it on the bench , put pen lines along it , got masking tape there , held it in a vice , ands used a panel file to bevel the edges .
Then carefully drawn it oveer Wet & Dry sandpaper . AND on the ends to get it dead vertical - Ends TRUE .

Real ones the end plates held with C'sunk head machine screws . Ya wanna be CAREFULL . Clamp Securely . Use Lube ,lots . Or the mount holes ( threaded ) will WANDER .


https://www.worthpoint.com/worthopedia/big-art-tongue-muffler-supertigre-46-117912313
Now I cant guess what this might be .



RUNNING IN . I do in COOL WEATHER . Carefully , unmuffled initially or LARGE muffler . AVOID picking up . Short bursts , lengthening . No Nitro .
Freezing , bitch to start . use 10 % fuel as PRIME .

Theres some Eather 11 1/4 x 4 1/2 or somesuch three blade carbon , for more relaxed 4 strokey run .For Switch half way up top or bottom loops of Vertical 8 , cording to kneedle ,
 The Black 10 x  6 3 Bl Tornados are excellent up to 2 kilo .

Theres 3/4 turn full 4 to full two . Allways , from scratch , go up ( warm Up ) into the steady 2 stroke , then back out 1/4 turn . And YOURE THERE . Miniscule for fine toon .
the CLAMP NUT so needles not stubborn , on spec. Get it Down CLINCHED so as theres no air bleed , needle'l be Just moveable . As you dont want it to .
( make a lump & rubber band or why for Transport , if your not perfect . 20 % oil 18 after a few hours . Will run on any fuel . 0, 5 , 10 % . A extra gasket ( or two ) with the 10% , if desired .

comment from Bill Bell . " Thats as good an engine run as Ive seen " ( At world chumps etc . ) so We'll picture the Tango Rip Off . 71 Oz . Usually a .46 muffler sans rear tube , sometimes .



WINDY used to ( get ) that machined down to THIS profile .   P.S.P.  stunt tounge muffler . About 1 1/2 long .

Dubro with edges whacked / routed .  8 or 10 2 mm to 2.4 mm holes .

USE MUFFLER PRESSURE IN ROUGH BUMPY AIR .

The Big Quite Mufflers work really well . With Tissue over silk detroit wing thrumming in the mist on a damp sunday morning everyone lying in bed thinks theres a U.F.O. in the Valley .  ;D

Online Dan McEntee

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6824
Re: Tongue Mufflers for ST.51s
« Reply #2 on: May 13, 2022, 08:49:49 AM »
  Yeah, I have been down that road, and made chip mufflers from the DuBro stock. ( I have some but don't think they make that any longer.)  The stock muffler manifold is mostly finished. All you need to do it plug the end. That can be done with a 1/16" thick aluminum disk that is press fit in and held in place with JB-Weld or welded in place if you have the equipment. Windy's tongue mufflers were really short, and had long slots instead of holes also. I'm looking for the least amount of restriction and back pressure I think. I'm just trying to decide if I want slots or holes., and how many of each.
 Type at you later,
  Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Air Ministry .

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 4978
Re: Tongue Mufflers for ST.51s
« Reply #3 on: May 15, 2022, 08:35:25 PM »
I was sure Id read in the aeromodellr Magazine about Bob's genisis ' Almost ' muffler - The slotted one .! Suggesting it might have some resemblance to a muffler , tho not acustically .

Got hold of a real one with 2 mm slots , my copy with 1 1/16 slots isnt quite either . Theyre just three 3/16 holes from face to third slot . these are 50 % depth .

IF you wanna trya slotted ne , Id suggest using a Razor Saw , so you get 1 mm or 1 / 32 ( preferable ) slots .

I have a P.S.P. thats drilled on the flat ( not slotted ) tho some turkeys been at it with a 1/4 drill . >:( Seem a few PICTURES of period stuff wth them DRILLED the usuall 8 or 10 holes .

5/64 is 2 m.m. , 3/32 is 2.4 m.m.

Offline Air Ministry .

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 4978
Re: Tongue Mufflers for ST.51s
« Reply #4 on: May 15, 2022, 08:44:08 PM »
This Ones on a OS 80 . The Idea ( theory ) is the shock waves arnt combined but staggered , so you get a softer ' multi cylinder ' like sound .

This isnt overly loud , ( half empty 1 ) , or is actually reasonably quite ( Glass half full !  ;) )



You can see the pinned 1/8 in ? internal ' cap ' . If your of machineist ability , got the gear and are accurate ,
Hard Alloy 1/16 or 2 mm end cap & C'sunk screws are tidy ( I used NAILS - panel pins ! driven in . )

So OUTER 2 are steel pins . You can see one sticking up . inner one is threaded for pressure line .
Theres twelve holes , three in four lines or   Outers on outer edge of the through channel /.

Find Edge hole posn's Locate & devide x 5 - fore 7 aft . stagger is 50 %  .  :P

The Long Length gets more ' cushion ' & expansion room , before the exit (s) .

One gets SWARF & swage / burrs inside the drilled exhaust holes . A knife inside so theyre not going to work loose & go up the cylinder while parked eases the paranoia . there .  ;D



genuwine scientific copy of Bob Hunts C.S.C. muffler . outboard .  . Was Quieter when it fell off .  LL~ ( noise away rather'n UP . )

The spacer is from a H P 40 . same bolt pattern . ' Chip ,muffler ' is three 3/16 in. holes . Cut drill end square for the final . to the outside of the third ' cut ' outlet .
So if you want loud , I think the flutes can work like reeds in a mouth organ, say . ! Certainly whistly rattly H F acoustic ' director .'



« Last Edit: May 15, 2022, 11:32:19 PM by Air Ministry . »

Offline Paul Allen

  • 2014 Supporters
  • Trade Count: (0)
  • Commander
  • *
  • Posts: 392
Re: Tongue Mufflers for ST.51s
« Reply #5 on: May 16, 2022, 04:16:40 AM »
Hi Dan
          There was a stunt flyer in England his name was Bill Draper, he designed the Superhawk and used the St muffler stub,
there is a photo in the May/June 2011 Stunt News, but its hard to see, looks like a pressure tap out the side
but cannot make out if it has holes in the blanked off end.
Paul
In OZ.


Advertise Here
Tags:
 


Advertise Here