O.S. .61 FX Engines
 

Well i have been searching for a thread on this Engine and have not found one yet. so i figured i would start one, So I can find out a little more about this engine i purchased. There are several threads that give bits and pieces of information. Not what i want to know. I'm intrested in finding out what variations of fuels have been used for succesfully breaking in the engine and prop Sizes used during break in Ect.

I want to break it in properly and i want to find out what fuels have been used. i know powermaster is a good fuel but unavailabe to me. So what other types are good ect. what size prop is best to break the engine in with. ect


Basically a thread that has anything to due with this engine it ups and downs. What to watch out for, how about the tuned pipe for this engine is it worth the extra cost and what does it due? buy using it does it increase the power of the engine or just give the engine higher rpm with more torque for speed.

So anything realting to the O.S. .61 FX engine experience would be great to hear about http://www.osengines.com/engines/fx.html

Thanks
Link:D

RE: O.S. .61 FX Engines
 

Link,


Do the break-in according to [link=http://www.rcuniverse.com/forum/m_1850473/anchor/tm.htm#1850473]this RCU thread[/link] and your engine will satisfy you for a long time.

If you check [link=http://osengines.com/faq/product-faq.html#q2]the OS USA Q&A batch[/link], they give you a different procedure, from what the manual (which doesn't bother to differentiate between ringed and non-ring engines) gives you.

RE: O.S. .61 FX Engines
 

It's a good engine...I've had one for several years and the only thing I've had to do is replace the bearings once. It's a little on the heavy side for this sized airplane though.

Tuned pipes and 3D type airplanes don't mix, so I wouldn't bother with one. If you want a good tuned muffler and don't mind spending a few bucks (about 70 ) a Jettstream or Nelson Ultra Thrust will really help get some more power out of it.

A 13 x 4W prop would work well too...and 10 or 15% nitro and a fuel with some Castor in it would be best...(IMO;)...(inside joke :D)

RE: O.S. .61 FX Engines
 

Well, Well, ... I have that .61FX already for about 3-4 years and although Dar is very nicely
helping here, I would say this engine takes what ever comes. It is rock solid and that means
a few things for me:
1. It is a bit too heavy and its power is a bit of shortage for the weight. In the same weight
better option is to take on .91FX; it takes about 30% more fuel but delives approx. 60% more
power output due to (I guess the lighter rigned piston).
2. It takes any fuel from 0% nitro up to 10% nitro and for more a shim should be added.
3. I had such spectacular crashes with this one so few believed the engine will be in one
piece, but it was, just wash it and it goes again. Perfect choice for slow trainer which would
be big i.e. well seen from distance and slow enough to take more than average speed.

As Suggestion: Sale it prior you even start it and for the money you get you can buy even
up to 2 pcs of any one of the Chinese copies (rigned or not) of the OS.91FX, for example
Magnum, Sanie, etc. There is no use of carrying too much weight with lower Power/Weight
ratio of OS.61FX. Of course, this would be the best to do unless someone is OS-addicted
and likes the look of the .61FX. In that case then is it better to add some money and
upgrade to .91FX. Alternatively, one can go to .50 ringed OS and there the power is the
same as for .61FX but at only 60% of the weight. I wander why OS went to .61FX, that
is looking to me as a kind of nonsense "design-trade-off". Any hints ?

Anyway, the reasons mentioned above might well explain why there isn't much of
comments on the RCU for this .61FX - people seems to circulate it on eBay :D

Cheers,
Nick





Rock-solid and resists almost any punishement,

RE: O.S. .61 FX Engines
 

Nick,


The OS.91FX does not make 60% more power than the OS.61FX.

It makes about 40% more, at a slightly lower RPM, since it breathes through same-size, or smaller bypasses (a malady of bored and stroked engines).


Try to compare them, using known prop sizes and you will also come to the same conclusions.

The piston's weight affects engine transition (acceleration), but not power output.

The piston's kinetic energy is transfered to the crankshaft (it speeds up its rotation) as it (the piston) is decelerated and transfered back to the piston (the crankshaft rotations slows down) as it (the piston) is accelerated.

This is the dynamics of reciprocation...

RE: O.S. .61 FX Engines
 

Dar,

I agree that I might be a bit too "emotional" about the 60% and they might be only 40% or
somewhere in between. I tested with even too many propellers, too many glow plugs and
used the Excel-data-sheet of Pe Reivers; there I come to the conclusion that both engines,
at least for me are pretty good at the range of 11000-13000. In fact the .61FX is a bit lower
RPM than .91FX. Surely, I am not thinking that anyone is the best for 3D; there are better
for that, for example, to my own expereince, the 2S Webra and MVVS of 15cc are lot
better for lower RPM.

But as it comes to the waste of energy of accelerating and decelerating heavier piston
I gues you need to specify why do you think that the power is not realted to that energy,
or I missunderstood you somehow; because the realtion Energy<---> Power is quite
always in place or here there is some secondary effect in place ?

RE: O.S. .61 FX Engines
 

Nick,


A discussion about the energy transfer principles does not belong in this thread.

It either belongs in a dedicated thread, or off-line between us.


It does take place, however, in all reciprocating piston engines.
Energy is never lost and if it is not given off as heat, it is just transferred to another moving, or spinning object.


As to using Pé Reivers PropPower spread-sheet; I use it all the time...

RE: O.S. .61 FX Engines
 

Loose the stock muffler and fit a Tower 75 muffler (16-17$) It will give a nice boost.
I used to own a FX 61 and it only turned APC 12.25-3.75 at 13100 rpm max peaked out. After fitting a Tower muffler plus my usual quick portjob it produced 14000 rpm on the same prop. That would pull your Twist around pretty good:) I don`t know how much each mod did contribute to the power boost, but the muffler alone will certainly help and it is cheap as dirt too

RE: O.S. .61 FX Engines
 

I have a 40 size TWIST with near 500 flights on it with a 46ax..
If I ware out this motor like my first 46ax, I will place a 55ax on it...
46 will hover with a slow pull out, so the 55 should just about perfect..

I have a 61fx on a four star 60...
The motor is heavy for the twist... could be a hand full in the air...

RE: O.S. .61 FX Engines
 

Walt & Sage,
My wife is HALF Norwegian. The OS 55AX will give Your Twist a Major improvement in Power & Performance!!! OS 61FX on My personal Planes is allot heavier and My TWO OS 55AX seem have more 3D Power and are allot Lighter. I switched out a OS 46FX with a OS 55AX on My X-50 Funtana and it Really Screams now. It feels more like 50% to 75% increase in that planes performance. I think Your Twist will do the same. It's serious improvement in all aspects of performance. You'll fly with allot spare throttle OR more Speed. Also play with different APC Props to find what works best for how You Fly and get QUICK Pull Out from Hover and UNLIMITED Vertical. I use My Tachometer and figure in Air The engine May Turn allot More RPM's!!! Be sure Break Engine in by Book and get some Break In Time on engine. KEEP it Rich so it doesn't go Lean in Air. I'd even consider adding a Oz or 2 of Castor oil to first few gallons of fuel to help protect from overheating especially doing 3D. Break In Is key to engines lasting a Long time and AX engines allittle extra Caster Oil is longetivty insurance to ME. I own 11 OS Engines and I only got back into model Aviation 2 years ago. I had 9 Years Flying U Control Combat .35 Engines Prior going into Army Aviation. I read and study allot about what makes these R/C Plans Work WELL !!! I'm Retired Aviation Maintenance Supervisor and worked also in R & D on Helicopters mostly. If looking for Plane that OS 46AX will Really Perform like putting OS 55AX in Your Twist Then Get Phoenix Funstar. http://www3.towerhobbies.com/cgi-bin...&I=LXEDP0&P=ML I get Mine from Tower Hobbies on internet. I wait for $20 to $30 Off of $200 Orders SALES. Tower Always has Sales Codes to Save $20 to $30 on Orders. Even Shipping Norway I'd Think Save Money. I love making Small Engine Plane Really Perform. All I do know I'm Fully Retired. Build & Fly My Planes. Have Fun and Enjoy. Hope This Helps? richgrow E-mail [email protected]

RE: O.S. .61 FX Engines
 

In any plane intended for fun-fly, or 3-D; weight is much more crucial than the little added power that might be available.

A heavier engine will probably make the plane significantly heavier than the weight difference between the engines... if moving things around does not suffice, you might need to add some lead in the tail...

A heavy 3-D plane flies like a floor tile...

RE: O.S. .61 FX Engines
 

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RE: O.S. .61 FX Engines
 

In short, Link.

If you have not bought this engine for your Twist .40 yet, just don't!


Any .40 will fly it better and a .40 frame engine with a larger displacement (.45, .46, .49, .51, .53, .55, .56....) will fly it much better.

Any A36-10XL size BLM with a 40A ESC will also do very nicely.


The OS.61FX for this model, is much more trouble than it is worth...

If you already bought this engine, I suggest you use it on another model that doesn't mind the added weight - not on a 3-D plane.

RE: O.S. .61 FX Engines
 

removed post due to not being very nice post.

RE: O.S. .61 FX Engines
 

Link,


You've been here on RCU for about 20 months, so you know none of us will intensionally misguide you.

What people here are telling you is that in essence, this engine is far from being a good one for this model.


Your profile states you currently have an Evolution .46 on this Twist .40 plane and what I am saying is that it flies better with this engine than it would with the OS.61FX.

A heavy 3-D plane flies like an anvil and this is what installing the .61FX will do to that Twist.


You have 4 other models in your hangar, none of which need this OS, so if you insist on using it, I strongly suggest that you add another model to your hangar...

Had you asked us earlier; before purchasing that OS, I believe none of us would have recommended that you do.


If you are having problems properly utilizing that Evo .46, I suggest you contact Barry (blw), who has several.

RE: O.S. .61 FX Engines
 

Link,

I am a bit dissapointed to read what you have just wrote. I wrote you what
OS.61FX is worth for, just a mid-size trainer with larger wings in order
to fit the excessive weight of .61FX. I am afraid that you have to live
with your mistake of purchasing this engine as long as you want
to keep it. You did not win anything here as you think. Everybody
does mistakes and nobody, even you, cannot change the gravity-law
and other laws in the Physics to counter the mistake(s) made by OS
company of have released this engine to the market. The manual
of this OS is very correct about the performance; nobody seems to
have found anything more and that resonance of another muffler
for sure depends on the exact constelation of too many factors like
Propeller, Fuel, GlowPlug etc and even Air Temperature and Humidity,
thus even if you spend more money on mufler you might never see
that effect.

If you look from another angle on what you have got as response
from RCU in general is in fact the Best Advice = sale it back to
eBay prior you have used any fuel on it and make a better choice
next time. That is why the people here talk so much about other
engines, isn't it simple ? Good luck !

RE: O.S. .61 FX Engines
 

Darzeelon

No i know no one would intentionaly mislead. No point in doing that. I purchased the engine cause i read the Twsit thread. and alot of people have been putting them on there Twist even a saito .72 is on one. And i wish i knew the post numbers to show what others who have used the engine say about it in the plane. But actually it's not important i started this thread to learn about this specific engine and the applications people have been using it on.






OS 61 engine experiences is what i really want to hear about here.:D

RE: O.S. .61 FX Engines
 

Link,


The OS.61FX is definitely not a 'dud'. With the exception of a few 'peelers' that were written about in this forum, it has a pretty good service record.

It is not particularly powerful for its displacement, as Dave Gierke of MAN magazine, in issue 05/2003 concluded.


It would be a nice engine to power [link=http://www.carlgoldbergproducts.com/airplanes/gbga1068.html]the Carl Goldberg Tiger[/link] and similar 'sport' planes, or a larger 'trainer' type, which I believe you have outgrown.

This plane will fly very nicely with a 12x6 prop, I believe; not with a 12.25x3.75W, or another 3-D oriented prop.


Because of the added weight, the OS.61FX, with a 13x4 prop, will probably not give your Twist a significantly better pullout from a hover, than does your current Evo .46...

RE: O.S. .61 FX Engines
 

Dar

Nope have a trainer it's got the saito .72 in it. i fly it now and then still pretty fun. but one is enough for anyone. Although a Piper cub would be pretty neat its kinda a trainer high wing aircraft. still i'm looking going toward a Warbird, if i can help it i want a follker tri wing good old red barron plane. but there rare hard to find in certain sizes.

https://www.balsastore.com/store/pro...l.php?prod=421
witch is way to big 1/4 scale need to find this plane in the OS 61 sized kit.

Was also considering a Speed plane for the OS.61 FX Pylon type racing plane seems pretty intresting or even a jet type aricraft with this engine on it. like a jetcat but with a 2 stroke on it i know they have jet type planes with 2 stroke engines on them have been considering that as well.

Seen an SR71 on ebay that would use a prop driven engine on it vintage model but it wasnt appealing. The old warbirds p51's p 40 warhawks ect are more apealing to my taste and old WW1 aircraft something with some histroy to it would probably be fitting for the OS. 61 FX.:)
.

RE: O.S. .61 FX Engines
 

It takes time to get on pipe and not a good choice for 3D. Plus you will go thru more glow plugs. Your going to need some tail weight to make up for .61 weight. Use the muffler you got with engine. 10-15% nitro with a blend of oil fine. A wood Zinger is light and will spin up fast. Try a 12x5 and keep RPM in the 12,000 RPM range.

RE: O.S. .61 FX Engines
 

.

RE: O.S. .61 FX Engines
 

LINK in all fairness to others on RCU , if you read your original post it sounds like your interested in buying an OS61 . Not that you already bought one and that is the only choice now.

RE: O.S. .61 FX Engines
 

Link...I picked up a few r.p.m. by rolling the lower lip of the ports on the outside of the sleeve.
I don't think aircraft engines turn enough r.p.m. to make all the other mods typically done to r/c cars engines worth while?

The tuned pipe will give ya a boost in top end at the expense of throttlability through the mid range, so it's a bad choice for 3D style flying.
I tried it a couple of times with 2 different .46's and pipes went back to a Tower/Aquacraft muffler.

Any good quality 10% nitro fuel w/ maybe a few oz. of extra Castor mixed in will work...and mine likes an O.S. #8 plug...and maybe you could use an 11 X 7 for break-in before going to the 13 X 4W for flying.

RE: O.S. .61 FX Engines
 

Was thinking it would probably make the plane to heavy and with all the advice on it not being a good idea. i think i will just stick it in a differnt plane, was considering this as a new project plane to put the OS in. :)

As in a fairness i didnt want o come off like a butthead or anything like that and hoped not to upset anyone with my thread. Still there are alot of claims that the plane would be off the hook with the 61 in it. One guys says he has a tower .75 in his twist and loves it lol.

I did come off like i didnt have the engine yet on my first post so i'm truly sorry for misleading anyone. I actually dont have the engine yet it in the mail on its way to me from hawaii. i couldnt pass up the opertunity to get a new os .61 Fx engine for 125 bucks. Considering what they usually run in price.

But there are alot of different model it will work real good in. So i'll just find an appropriate engine for the Twist and finda differnt plane to Put the 61 in i think the bobcat would be a really cool plane to try this engine in. But there are others:eek:

RE: O.S. .61 FX Engines
 

Did you see that they call it a biplane in the ad?