Gregor32

My Feedback: (1)

Im in a quandary, im tossing up between these two engines one of which will find its way into a 72" warbird at about 12lbs, everything i read about the 108 sounds positive, is there a big difference between the two of them? the 120 would be new and the 108 used but only just, i would love to hear some pros and cons.
thanks Greg

Ken6PPC

The 1.08 is heavier (26.5 oz. without a muffler) than the 1.20 (22.9 oz. without a muffler), according to OS's specifications.

Will you need to add nose weight? If so, the extra weight of the 1.08 won't hurt you.

Obviously, the 1.20 is more powerful than the 1.08. The 1.20 has parts available, while the 1.08 probably won't. They are both ringed engines, and they are both 2 cycle. Both have excellent reputations for reliability.

Just look at the facts and specs, and decide which one better accomodates your style of flying and which one you want...

I'd say either one would fly your warbird.

masama1107

My Feedback: (44)

O.S. 1.08 FSR, in my opinion, the very BEST engine OS has ever made. I own two (and selling another one in one of my ads) of them and absolutelly love them!!!
Reliability is bar none, THE BEST!!!!, power is awesome as well.
The 120 is a great engine as well, but it is a modern engine and I don't know how long those "modern engines" (FXs, AXs, etc) will last. For sure, they won't even come close to the old FSRs in longevity.
Hope this helps!!!

av8djc

My Feedback: (4)

DITTO!

David Bathe

Totally agree.
The 1.08 is an absolutely marvelous engine.
Old school long stroke... with serious balls!
I don't think the 1.20 can compare power wise.
This is old school shear grunt. A different type of power delivery. As I said in another thread, it's the closest I've every come to a 4 stroke... in a two stroke.

OS would still be making them except it totally shames everything that followed.
Thus thet've tried so hard to remove all reference to it.
Everything they've produced since has been seriously lacking "stonk"!

Ken6PPC

I have read good things about the 1.08 myself. However, I don't have any personal experience with one.

I do have to wonder... what will you do when you need a part for one of these engines? I believe they have been discontinued for a LONG time now, and NOTHING lasts forever.

I had an opportunity to pick up a used (and discontinued) Spitfire with an OS 1.08 in it at a good price, but I passed on it because of the inavailability of parts for either one, and the fact that it had fixed gear, which I don't like on a warbird. Perhaps I messed up on that one, but the plane showed some wear, and I prefer 4S engines anyway.

rcdude7

My Feedback: (264)

Nope, the 1.08fsr was discontinued recently, right when the 120ax was introduced.


The 120ax is a nice engine, but I'll bet it is cheaper to mfgr than the 1.08 and it has a different look similar to the rest of the ax engine line.

kochj

1.20 AX not having the low end that the 1.08 had????

I would hope this isn't true, but then again, I only have the 1.20 AX, and wish
that it DID have more LOW END TORQUE>..............

Perhaps, this is what was refered to ????

I will say this,,,,,,,,,,,,,,,,,,,,,,,,
THe OS 1.20 AX is easily my BEST 2-stroke, and probly my BEST performance GLow engine in my ALcohol Aircraft enge Stable....
It is reliable, has great power ( has a muffled tuned pipe) can Idle all day long, and not load up....
My BEST Sport Alcohol engine, is my OS 1.60 Gemini on ignition... ....

I have mainly focused my attention to Gas engines....
If I DO have any Alcohol/nitro engines, they have better be reliable, and the 1.20 AX is more so than my 3-Magnum .91 4-stroke engines....

hope that helps...

kenhiraihnl

i have an os1.08fsr that has been rebuilt w/ sus bearings and performance specialties' abc piston/sleeve...it'll go in a venusII (a little nose heavy), but should pull it around very nicely...it's been broken-in on a test stand, and as stated in an earlier post, it's as smooth and torquey as a 4-stroke...ken

Gregor32

My Feedback: (1)

Thanks guys for your replies, everything i read on the 108 is very positive and there doesn't seem any negatives for the ax120 so i think i will try both, also over here in Australia my LHS still has new stocks of the os108fsr's listed http://www.rojshobbies.com/Engines.html a bit pricey tho.
Regards Greg

David Bathe

Exactly, check that price.
Amazing for an out of date, old school engine.
The numbers are telling you something.

I'm all for new technology, pushing things forward, out with the old etc but 2 stroke engine tech... seems to be going in one direction: More cc's in a smaller, lighter case.. a little high reving compact jewel.
I don't know if they haven't forgotten something: Meat! They're all dinky and dandy, look beautiful, operate flawlessly... but where's the beef?
The centuries old Moki 1.80... what a monster... and that's all with 0-5%! No BS balls.
The moki 1.35 is/was pretty damned good also. I had the OS 1.08 in a CG Extra and the Moki 1,35 in the slightly larger CG Sukhoi.
Not that shabby I'll tell you.

kochj

I had not given it too much thought over the last few years, as I had moved over to mainly gas engines.....
But it does bother me a bit, how my OS 1.20AX does not have the low end grunt of a 4-stroke.....4-3D anyway.....
Yes, I have a pipe on it, but it is a very very concerverative tune.... (very long header)
IT flys very good pattern though....
I think that the future of non-scavageing 2-strokes will be shti canned in the future anyway, due to pollution
control....(look at the motocross bikes and all the recreation vehicles, and PWC's)
Soon, we will all be using 4-strokes and electric's.....

It is too bad, that they (o.s.) can't get it together though.....hmmmmmmm???

asmund

Why do you expect a twostroke to have the same low rpm grunt of a similar sized fourstroke???? It`s not gonna happen you know

kochj

Yes I realize that,,, I was just expecting a bit more.......

I have been flying my 69" yak with a 1.20 AX piped and it is a absolute rocket....
I however would have liked to have more low end...

Rudolph Hart

OK you are welcome to come over and fly my 68" dolphin models 330 with an fa220 up front,lots of propeller torque and lots of fun

kochj

Wow~.......
[sm=spinnyeyes.gif][sm=confused_smile.gif]

That sounds a bit overkill......

~~~~picts please~~`

do335a

It just so happens that I've had both the OS 1.08FSRT and the OS 1.20 AX.

I put at least several hundred hours on the 1.08 and never as much as had the backplate off. Super reliable its entire life. Very strong too, especially considering that it was not designed to be a low revving engine.

I put only about 6 hours on the 1.20AX. It was a very nice handling engine.

My preference overall was for the 1.08. The 1.20 was a lower revving design, rated at higher output and a bit lighter with smaller overall dimensions. The 1.08 was installed in many airframes and had tremendous power in anything that weighed 10 lbs. or less. In my 1/4 size clipped wing Cub, at about 14 lbs., it was not lacking in any way. The 1.20 AX was in a Sig Mayhem at 8lbs. all up weight. It performed well but just did not seem to have the grunt of the 1.08.

There's still a bunch of 1.08s floating around and you even come across them NIB. As for parts, from my experience, I would not concern myself with that. I never needed anything.

Given the stresses involved, it could very well be that these newer, smaller component, highly stressed engines turn out to be time bombs. Come to think of it, my Rossi Super Comp Turbo .21 for a car (early 1990s design) was an example of that sort of understanding. The crank, crank pin and rod were larger than you'd find in a present day 60. It was intended to top out at 30,000 rpm. No time bomb there.

skydevil1

Tower has lots of parts for the 108 in stock