rotflmaf Not that's comedy!



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OK Kostas -- here it is --

http://www.rcuniverse.com/forum/m_3817631/tm.htm

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Harry, I too did not see the point. It appears that the head bolts were the source of the problem.

Dar, in contrast to Tower's site, the manual says "For the best performance, a fuel containing 5% to 20% nitromethane is preferable". It also recommends three plugs: A5, A3 and #8.

In principle, I agree with this. However, if one discovers additional benefit from upping the nitro beyond recommended levels, this is good too. One should not be too rigidly bound by institutionalised thinking.

That notwithstanding, I still recommend running 15% in the .50 SX based on what I've seen in the field.

Harry,


OS apparently does not!

Since the manual that you have was written, OS has updated its home web site.
Please read [link=http://www.os-engines.co.jp/english/line_up/plug/pluindex.htm]this web page[/link].

The only aero engines, for which the A3 glow-plug is recommended are LA engines up to .40 and all smaller than .32 engines.

The .50SX does not fit into this selection and the A3 is for sure too hot for it.
The OS #8 is the only plug that does fit the bill.

The same web page says the A5 is for .61 and larger engines.

The shortcomings of the .40FX-.91FX manual immediately come into a demeaning view.

The A3 is apparently not recommended by OS for any of the above engines, but in the manual it appears...

The fuel recommendation of up to 15% nitro is indeed from Tower.


And it is not institutionalization I am after, but optimization.
Using the right fuel and the right glow-plug, will give you the best performance and the least fuel waste.


Aren't we all trying to make this hobby more affordable?

Just wasting more expensive fuel and more of it, is just putting us all in reverse.

LOL, If I believed every thing I have read in the owners manual I would have thrown out my ASP Red heads long ago. The manual says to run them on 15% nitro. I think it would have to be 40 below zero for that engine to run on 15% nitro without having a meltdown from the detonation. Maybe a missprint, they must have accidently put a 1 in front of the 5.

This link is only to a simplistic reference as a guide to beginners on a single web page devoted to their plugs. The manuals Harry is referring to are in another section of that site and all that I've looked at give a range of plugs that are suitable to be tried to find the best one for a particular application of that engine. Also it seems that every engine of any size is shipped with a #8 plug.

I'll agree that using the right plug gives the best performance but to assert that only the plug listed on that chart is the one to use is incorrect.

OH HARRY LAGMAN Thanks for the put down. First I didn't start the Super Tigre posts. And no I don't own a OS 50 . Second you better follow your own advice ,you spent your time at the field tinkering instead of reading the posts. What are you reading for anyway? Two members at our field have OS 50's and just loved them , but then late in our flying season they just puked. Early winter so I haven't seen them at the field to find out what happen to their engines. And the point is when a bearing breaks there is usally not much warning.

Hey Harry You got on BRITBAT's case for his forum post (loose head bolts) you missed the point. What about the other guys that actually had engine failures in that post. Oh you forgot to read that part too. You seem to know alot about the OS 50 bearings. But I thought those were great threshing machines with no problems. RIGHT?

Speedster - it would be interesting to know what happened to your fellow club members' engines. Do let us know when you find out.

Dar, if I'd followed OS's guide on plugs to the letter, I wouldn't have discovered how well the OS Type F works in some two strokes (examples: my Jett .90 and a buddy's GMS 1.20). If possible, I like to try two or three different plugs in a particular application just to satisfy my curiousity.

Brian,


I know exactly where the manuals Harry were referring to are. The manual is the for the .40FX, .46FX, .50SX. .61FX and .91FX.

It is the exact, same manual that you can download at the [link=http://www.osengines.com]US dealer's website[/link].


This manual does state the A3, #8 and A5 plugs as suitable.


Yet the OS web site shows the info below:


The A3 plug, although it is in the manual; according to the plug page in the OS web site, is good for non of the engines covered by this manual.

I know exactly which glow-plug is suitable for the OS.50SX; the #8 and nothing else.
...Well, maybe the A5, but only if you shim the head and use more than the recommended percentage of nitro...

And I wrote about the possibility of using a hotter plug than the suitable one for engine: Possible, but incorrect.

Hi Dar.
I checked the original OS site and the A3 is reccomended only:
<< For R/C Aircraft
Running-in, Engines smaller than .32 capacity
Engine types: 25SF, 25FX, 10-40LA>>

Kostas,


I updated that post: From 'up to .32', I changed to 'smaller than .32'...

[sm=thumbup.gif]

My first OS 50 puked and i sent it back for a new one OS promptly sent me a free replacement!!!...3 years ago... 3 summers on the new motor, 10-15 gallons later it runs great!!!

Adam,


Please read post #23 in [link=http://www.rcuniverse.com/forum/m_3402107/tm.htm]this recent RCU thread[/link].

10-15 gallons is virtually nothing...

Yet not long ago you'd have been telling him it needs new rings. Remember when you used to insist that a ringed engine had a life of 75 hours when I, and others, were telling you they'd go for hundreds of hours?

Brian,


Although I am capable of giving good, knowledgeable advice to many modelers, I keep my eyes and ears open and sometimes modify my views.

My estimate of 50 hours for ring-life and for ABN setups was from Harry Higley's books...

There was another thread here that estimated an average engine life of 13-14 hours...


Obviously, when an engine is perfectly maintained, even more sensitive setups will live much longer than 50 hours.
When, however, one tries to extract every last RPM from his engine, using the leanest possible needle setting and the minimal percentage of oil, even 13 hours may prove to be a gross over-estimate.

If someone is an imbecile and abusive to his engine, 13 minutes could be a more accurate...