NEW OS MAX-120AX RING !!!

NEW OS MAX-120AX RING !!!
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NEW OS MAX-120AX RING !!! - 9/28/2005 3:24:26 PM

STG

Posts: 3498
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From: New Richmond, WI, USA
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This looks great O.S.!!! Finally some new technology for 2 strokes.

http://www.os-engines.co.jp/english/index.htm

This is the second AX Series engine after 46AX.
Standard silencer is compact and easily enclosed in most cowls. Also, Extension adaptor and 90 degree adaptor offers several silencer installations.
Specifications: MAX-120AX RING

It is a torquer like the 1.6FX....usable rpm is only up to 9,500--small transfer ports(& case size).

If it is really only 21oz plus muffler that means with a good turbo jet it will be 28oz--same weight as YS110 and will beat it in power!!!!

2 strokes are back on top baby!!!

Notice no remote glow.

http://www.rcuniverse.com/forum/m_3380884/tm.htm

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RE: NEW OS MAX-120AX RING !!! - 9/28/2005 9:51:32 PM

Posts: 289
Joined: 4/25/2002
From: Birchwood, MN, USA
Status: offline

I can't say that I am pleased with some of the features of this new engine. First, the weight shown on the OS Web site is a contradiction. 647 grams divided by 28.35 grams per ounce works out to 22.82 ounces, not the 20.88 ounces shown on the OS Web site. I would think that the OS engineering staff can do better than this, so I'll blame their marketing department

. I would tend to believe the higher weight of 22.82 grams because the OS .91 FX (25% smaller) weighs 550 grams or 19.4 ounces. Here is the link for the OS 91 FX:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBY47&P=0

Second, five cylinder head bolts rather than six or eight bolts is a cost-cutting measure that results in more profit for OS/Futaba, not a better compression seal and longer lasting engine for the modeler. The OS 108, one size smaller, has eight head bolts:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCK26&P=Z

While the OS 140 RX, one size larger, has eight cylinder head bolts:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCK25&P=Z

and the OS 160 FX has six cylinder head bolts:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXUT09&P=Z

Third, even if this engine were to sell at a whopping 40% off MSRP or $270.00, it would still not be price competitive with other excellent engines in this class such as the Moki 135, Thunder Tiger 120, Webra Speed 120, etc.

Fourth, the standard muffler appears to be a copy of the Thunder Tiger 120 two-way muffler, but from the picture, it seems to extend pretty far down and could be difficult to enclose inside some cowls such as that found with an Extra.

To OS's credit, they finally moved the 120 AX needle valve to the right location.

Bruce

(in reply to STG)

RE: NEW OS MAX-120AX RING !!! - 9/28/2005 10:07:25 PM

Hobbsy

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From: Colonial Beach, VA, USA
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I think you can throw out the five head bolt issue, I have several SuperTigre, OPS and MVVS engines with four, never a problem and I think all my Enya fourstrokes have five. My two OS LAs .46 and .65 I converted to Diesel also have four head bolts and again no problem.

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(in reply to cu. in.)

RE: NEW OS MAX-120AX RING !!! - 9/29/2005 5:59:04 AM

Posts: 289
Joined: 4/25/2002
From: Birchwood, MN, USA
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I agree with you on the smaller engine sizes. Bill W. designed the K&B Sportster Series with four-bolt heads, and of course, the OS 46 AX has a four-bolt head. But I think that when you start talking 120 size engines, the span between bolts gets pretty large with five bolts. It is probably OK for normal running, but what happens during a lean run or two? In this situation, more head bolts would help by providing more clamping points to reduce head warpage.

I am not an engine historian, but I can't think of any two stroke model engines larger than 120 size that have less than six head bolts. OS's competitors in this engine class use six bolts. Why introduce a new product at a high price against strong competition and have any potential liabilities? I happen to think that OS has lost the good engineering common sense that they used to have when they were privately owned. Just look at the mess they made with the last two 70 four stroke engines they introduced.

I suppose that time will tell as to the durability of the five-bolt head arrangement.

Thanks for your reply,

Bruce

(in reply to Hobbsy)

RE: NEW OS MAX-120AX RING !!! - 9/29/2005 7:07:27 AM

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From: Baton Rouge, LA, USA
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cu.in

I don't apperciate your comments

1st, O.S. AX is a good series, specially now because they are using chrome on the 46 and instead of nickel

2nd, this wieghts less than the thunder tigre 120 or the ys 110!

3rd, Look at the cool muffler! Hell its a free inverted pitts muffler

4th, the lovley towerhobbies with thier nice 25-30 dollar off order on this engine will make it in the 220 dollar range for sure.

5th, I for one am really happy this came out

2-strokes are going to be king again.... muhahahahhaahah

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RE: NEW OS MAX-120AX RING !!! - 9/29/2005 2:35:08 PM

STG

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From: New Richmond, WI, USA
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Dang, I forgot all about the bad 70 four stroke that OS has come out with. I guess I was just expecting the best from them & wanting some new 2-stroke technology to hit the market.

Thinking about it, if OS were most concern about offering top performance they would have made the new .46ax maybe a .53 or a .56--maximized its displacement?

--------------

I have been thinking about the right prop for this motor and looking at its spects it shows max power to be a 9000 rpms and usable RPM rage to be 9,500 max. Not surprising as with its light weight it has to have small transfer ports which will cause the motor to go to sleep at high RPM. I would guess that the port timing compliments the small transfer ports making this a very torquey 120 2-stroke.

This being said, people that put something like a 15 x6apc on this motor will end up disappointed to find out it does not turn it any faster than a .91FX ( low 10's).

A 16 x6 will most likely be the a good prop to maximize thrust and still have the good forward speed, but I would guess it will pull a 17 x6apc with a little bit slower spool up. I am thinking a good 17 x6 Pro Zinger would be a very good prop as it would load the motor closer to 9000 rpm and still have fast spool up. Too bad that a 17 x6 is kind of an odd prop size.—cannot find it in a Pro Zinger or a wood Scimitar.?

A 17 x6 will be necessary if a semi tuned exhaust is used on this motor you will want to run it no higher than 9500 rpm to get max power.

Looking at Jett's 120 motor they show performance to be

BSE 1.20L R/C with semi tuned muffler AAC
16x8apc @9,200 27.8oz

http://www.jettengineering.com/

< Message edited by STG -- 9/29/2005 2:40:04 PM >

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RE: NEW OS MAX-120AX RING !!! - 9/29/2005 9:18:29 PM

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Disco Wings
What makes you think that OS uses chrome on the 40 AX?

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(in reply to STG)

RE: NEW OS MAX-120AX RING !!! - 9/29/2005 10:18:22 PM

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From: Vienna, VA, USA
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here is a bigger pic:

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RE: NEW OS MAX-120AX RING !!! - 9/30/2005 1:17:58 AM

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From: Baton Rouge, LA, USA
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quote:

ORIGINAL: MrMotor

Disco Wings
What makes you think that OS uses chrome on the 40 AX?

I called hobbyservices and they said the Bi-Metal Liner is Chrome and 2 metals.
The original AX used Nickel, then they switch to "L"

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RE: NEW OS MAX-120AX RING !!! - 9/30/2005 1:30:56 AM

Posts: 644
Joined: 4/11/2005
From: Baton Rouge, LA, USA
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Also, here are the prices:

269.99 O.S. 120 A.X. w/out muffler

299.99 O.S. 120 A.X. w/Muffler

TowerHobbies.com

Release date: Late November

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RE: NEW OS MAX-120AX RING !!! - 9/30/2005 3:20:14 AM

Posts: 3515
Joined: 5/15/2002
From: Westerly, RI, USA
Status: online

The price is high but it looks to be a good design. I am looking forward to this engine coming out. I hope it runs as well on 5% nitro as the 160FX. The small ports should give good economy.

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RE: NEW OS MAX-120AX RING !!! - 9/30/2005 3:35:07 AM

STG

Posts: 3498
Joined: 7/3/2003
From: New Richmond, WI, USA
Status: offline

quote:

ORIGINAL: Skypilot_one

The price is high but it looks to be a good design. I am looking forward to this engine coming out. I hope it runs as well on 5% nitro as the 160FX. The small ports should give good economy.

Yes. Although, I have found that the 108 gives great economy on a 10 pound plane and a 16 x6 prop & that has large ports. Will most likely improve though as you say.

How much do you think that stock muffler will weigh? It might be a real choker though as sound is more & more of an issue than ever. I think a good Jett muffler will be the way to go.

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RE: NEW OS MAX-120AX RING !!! - 9/30/2005 6:53:28 AM

Posts: 289
Joined: 4/25/2002
From: Birchwood, MN, USA
Status: offline

STG,

Like you, "I was just expecting the best from them & wanting some new 2-stroke technology to hit the market". I think that the engine will be just fine overall, and actually can't find anything else to criticize. FYI, the two-way, 90 degree Thunder Tiger 120 muffler weighs 234 grams or 8.25 ounces with mounting screws and lock washers. I would think that the OS 120 AX engine muffler would be close to this weight.

Disco Wings,

I guess you thought that I was bashing OS and the 120 AX engine. As far as OS is concerned, I still feel that they can do better, and I stated why. In the past, when OS was privately owned, I didn't think twice about engine quality or longevity, and OS was my number one choice. Back in the late sixties, I flew a Phil Kraft "Kwik-Fli" with an OS Max H60F R.C. cross-flow engine. I still have my OS 60 FSR that I flew in the seventies, along with numerous other FSR engines. I even bought a NIB 1940 OS K6 ignition engine. I'm not really that old....the engine is one of the few replicas that OS made of their very first engine that was built in 1940.

I have been an enthusiastic OS customer for many years, but I feel that they can do a better job on the products that they offer today.

Bruce

(in reply to STG)

RE: NEW OS MAX-120AX RING !!! - 9/30/2005 7:26:05 AM

William Robison

Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
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Matt:

When I first saw the picture you posted I thought "Dang, OS is trying to `Outugly' the Evolution engines." On second look I decided that while they are trying, they haven't quite made it.

Disco:

OS is still using a nickel plated liner, there is absolutely no chrome in there. OS went to ABN cylinders, and didn't bother to change the ABC on the boxes. They got caught when the 46 FX engines started shelling their liners with amazing regularity, followed by many 91s, and other sizes as well. When they brought the 46 AX on the market they called it "Advanced Bimetallic Liner," but it was still the same cheapo nickel plating. OS has finally gotten their ABN quality up to the level of the Thunder Tiger's ABN cylinders. Maybe OS sent their engineers to Taiwan to learn how to do it - I've only heard of one TT liner failure, and that was foreign object damage.

Let's hear no more about the AX having a chromed liner, please.

Bill.

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RE: NEW OS MAX-120AX RING !!! - 10/1/2005 2:18:47 AM

Posts: 162
Joined: 11/12/2002
From: The Great Midwest, USA
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quote:

1st, O.S. AX is a good series, specially now because they are using chrome on the 46 and instead of nickel

2nd, this wieghts less than the thunder tigre 120 or the ys 110!

3rd, Look at the cool muffler! Hell its a free inverted pitts muffler

4th, the lovley towerhobbies with thier nice 25-30 dollar off order on this engine will make it in the 220 dollar range for sure.

5th, I for one am really happy this came out 2-strokes are going to be king again.... muhahahahhaahah

I'm with William, they are catching up on the ugly race with Evolution. To address some of my thoughts to one of the posts:

1, Like Willia