RE: 4 stroke pick?  
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[Poll]

4 stroke pick?
Saito 125
  43% (40)
OS 120
  19% (18)
YS 120
  36% (34)


Total Votes : 92
(last vote on : 9/29/2008 9:49:35 AM)
(Poll will run till: -- )
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RE: 4 stroke pick? - 7/30/2006 3:59:00 AM   
TimC



Posts: 2261
Joined: 1/7/2003
From: Lone Pine, CA, USA
Status: offline 		StevL, if you're OK with a two stroke, here's a real stump puller. A 1.20 in a .61 size package.
Jett BSE 1.20L R/C with muffler** AAC
9,200 RPM
16x8 Prop
27.8oz. Weight

(in reply to StevL)
       Post #: 51

RE: 4 stroke pick? - 7/30/2006 5:41:57 AM   
Richard L.



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From: Redmond, WA, USA
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quote:

ORIGINAL: torque wrench

Motor, I went back and posted them, I need Richard to give me his .91 FZ numbers, mine aren't too good. My .91 may have a problem but it did not seem like it.


YS .91FZ swinging a Graupner 15x8 prop at 9000 rpm max on Powermaster YS 20/20, richened down to 8800 rpm for flying: Spit Show Pass @ Full Throttle

This engine has 5 gallons through it. Correction, the engine has a lot more than 5 gallons through it and has very low compression (probably needs a ring job), but it still runs like a beast.

< Message edited by Richard L. -- 7/30/2006 6:30:53 AM >

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Tamiya Panther, Tamiya King Tiger(3), Tamiya Tiger I, HL Tiger(3), HL Panzer III(2), HL Panther, HL Pershing, HL Bulldog, WSN T-34/85, HE Leopard 2A5

(in reply to Hobbsy)
       Post #: 52

RE: 4 stroke pick? - 7/30/2006 2:01:08 PM   
Hobbsy



Posts: 10844
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		Thankyou Richard, I'll run my .91 this PM on the WildCat I used in the Saitos, the CoolPower 20/20 belongs to a friend and may not be good. I run my YS' on WildCat ProMix 20% which has 18% 95/5 syn castor blend, I'm out of it though.

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       Post #: 53

RE: 4 stroke pick? - 7/30/2006 4:59:37 PM   
PlaneKrazee



Posts: 3579
Joined: 5/15/2002
From: Westerly, RI, USA
Status: offline 		The Enya 155 will make more power on less fuel than the YS110 but it is larger, weighs a few ounces more and requires you to make a velocity stack for best fuel efficiency and performance.

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       Post #: 54

RE: 4 stroke pick? - 7/30/2006 5:44:29 PM   
Hobbsy



Posts: 10844
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		OK, after much ado and experimentation I managed to squeeze 8,610 out of the .91FZ, I cannot match Richards 9,000. The things I did were, rebuilt the regulator to cure a really fat mid range and no idle, changed from a McCoy 4s plug to a Fox Miracle, good for 200 rpm because I could run it two clicks leaner with the Fox. The results were,

8,405 rpm on the WildCat 15% Premium Extra.
8,610 on the CoolPower 20/20 all synthetic.

I also tried a Davis InCowl Muffler, usually good for a couple of hundred rpm on most fourstrokes but not on this one, same rpm just a whole bunch quieter.

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       Post #: 55

RE: 4 stroke pick? - 7/30/2006 7:29:39 PM   
Richard L.



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Joined: 7/28/2002
From: Redmond, WA, USA
Status: offline 		I forgot to mention that I ran my .91FZ with just a straight pipe, which might have given me a couple hundred of extra rpm.

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Tamiya Panther, Tamiya King Tiger(3), Tamiya Tiger I, HL Tiger(3), HL Panzer III(2), HL Panther, HL Pershing, HL Bulldog, WSN T-34/85, HE Leopard 2A5

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       Post #: 56

RE: 4 stroke pick? - 7/30/2006 7:31:09 PM   
Richard L.



Posts: 8775
Joined: 7/28/2002
From: Redmond, WA, USA
Status: offline 		Also, I'm at sea level and the temp was in low 60's at the time of the tach reading.

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Tamiya Panther, Tamiya King Tiger(3), Tamiya Tiger I, HL Tiger(3), HL Panzer III(2), HL Panther, HL Pershing, HL Bulldog, WSN T-34/85, HE Leopard 2A5

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       Post #: 57

RE: 4 stroke pick? - 7/30/2006 9:04:27 PM   
Hobbsy



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Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		I'm pretty high here Richard at 28 feet, the Potomac river is three miles wide here.

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       Post #: 58

RE: 4 stroke pick? - 7/30/2006 9:57:31 PM   
MOTORMAN37



Posts: 2129
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From: CLINTONVILLE, WI, USA
Status: offline 		A YS 1.60 will make lots more power than a Enya 1.55, and it only ways a couple ounces more.

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       Post #: 59

RE: 4 stroke pick? - 7/30/2006 9:59:32 PM   
bla bla


 

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From: Oslo, NORWAY
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quote:

ORIGINAL: Richard L.

I forgot to mention that I ran my .91FZ with just a straight pipe, which might have given me a couple hundred of extra rpm.


Thats makes quite a difference. Mines being run with an Hatori Header and Pipe. Long and real restrictive, but super quite.


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RE: 4 stroke pick? - 7/31/2006 12:55:12 AM   
PlaneKrazee



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quote:

ORIGINAL: MOTORMAN37

A YS 1.60 will make lots more power than a Enya 1.55, and it only ways a couple ounces more.



That would be on twice as much fuel too.


The 155 is the most fuel efficient to power engine I have ever flown, seconded by the OS 160FX and or Moki 2.10.

The Moki 2.10 makes a 4377 of a lot more power than a YS 1.60 and when you figure fuel weight into the equation it can do it at the same weight.

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       Post #: 61

RE: 4 stroke pick? - 7/31/2006 1:15:25 AM   
Tiroloco



Posts: 114
Joined: 7/5/2004
From: Mexico city, MEXICO
Status: offline 		Have you ever took in to pieces every one of this three engines?
In my opinion O.S. and YS are better conceived/made than Saito.
I admit that I´m a Saito fan, but I have to be honest and say that Saito has some design/manufacturing mistakes than O.S. or YS.
For example, take a look at the connecting rod of both O.S. and YS, you will find a brass bushing on each side, not for Saito, they simply don´t use any bushing in to their connecting rods.
O.S. has a modular design, which allows you to change, for exemple, only the head, not for Saito or YS, you must change the whole cylinder just in case you need it.
The only mistake I´ve found at O.S. is the restrictive muffler design, I own an O.S. FS-91 Surpass II pumped and I opened the muffler exit just 1.5 mm and the engine gives the punch I can´t get with my Saito FA-100.
With this little mod, running both engines with 30% nitro Heli powermaster, I got 10600 rpm peak with my FA-100 turning an APC 15X4W (10400 for flight after riching the mixture) and with my O.S. I get 10400 rpm peak same propeller and running it at 10200 rpm.
Not bad for a 91 class 4 stroker.

Best regards.

(in reply to MOTORMAN37)
       Post #: 62

RE: 4 stroke pick? - 7/31/2006 2:05:55 AM   
XJet


 

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quote:

ORIGINAL: Tiroloco
For example, take a look at the connecting rod of both O.S. and YS, you will find a brass bushing on each side, not for Saito, they simply don´t use any bushing in to their connecting rods.


Yet you don't see that many Saito's with stuffed conrods eh? Most rods will outlast a couple of sets of rings and bearings, so has Saito got their design "just right" or are OS and YS simply overdesigning theirs? Remember that 7075 aluminum in some tempers is about as hard as low-carbon steel so we're still talking about a very durable material here.


quote:


O.S. has a modular design, which allows you to change, for exemple, only the head, not for Saito or YS, you must change the whole cylinder just in case you need it.

But that adds extra weight and the designers at Saito have obviously decided that they want to build the *lightest* engines for a given displacement -- which makes them very popular with those of us who fly 3D (where weight is far more important than it might be for a warbird or sports model).


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RE: 4 stroke pick? - 7/31/2006 2:36:46 AM   
TimC



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From: Lone Pine, CA, USA
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quote:

ORIGINAL: Tiroloco
The only mistake I´ve found at O.S. is the restrictive muffler design, I own an O.S. FS-91 Surpass II pumped and I opened the muffler exit just 1.5 mm and the engine gives the punch I can´t get with my Saito FA-100.
Best regards.

Tiroloco, Kiwi Harry Lagman also had success upping the max rpm's of a .91 Surpass by changing to a thinner walled tubing for the header pipe. I don't know if he drilled the muffler outlet or not. I've noticed myself on some O.S. four strokes, when the header pipe was bent at the 45° angle, the tubing was crushed enough to possibly impede the flow.

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       Post #: 64

RE: 4 stroke pick? - 7/31/2006 3:05:48 AM   
MOTORMAN37



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