Marian

I would like to move to 3d planes in .60 -91 size.
I am considering:
TH .75 : + price, power - ABC, maybe unstable quality
GMS .76 ?
Super tigre .75 : + ringed - silencer
Super tigre .91 : + ringed - silencer

And maybe MVVS, because they can be bought here for aproximately the same price as ST, but they are too loudly on tuned minipipe.

How these engines perform in 3D planes?

Marian

Gringo Flyer

My Feedback: (18)

Of what you have listed I would go with the ST90.

First of all between a .60 .75. or .90 your weight is the same but you get more power of course out of the .90.

Also the ST90 likes to swing big props at lower rpms and thats good for 3D. The only problem with the ST90 is that its a little bit heavier than some other engines in the same class.

You didnt mention it but a OS90 would be a good option.

A lot of folks are big on the Tower engines, but I have had 2 and I couldnt get either one to run right.

w8ye

My Feedback: (16)

For some reason the TH 75 has a more popular mention on RCU than the GMS 76. They are made by the same company. The TH 75 is ABC and the GMS has a Dykes ring.

Kostas1

Despite the fact that you don't list ANY OS engine,i would suggest an OS 91 FX or (for less power) the OS 65 LA with tuned pipe.
Enjoy.
Kostas

Bodge

The MVVS 91 is a good 3D engine - it's light and easily handles a 16 x 4. I hadn't noticed it being noisy, with a throttle pipe.

OS are too expensive for their performance and don't last particularly long - that from my experience.

May be cheap in Greece, but not anywhere else...

Kostas1

You said that OS engines break down very easy?
And that's your personal experience?
Then...
you must learn how to brak-in your engine 1st.
And then come back to post...
Bye bye[sm=lol.gif]

britbrat

My experience with the GMS 76 has not been positive (two examples so far) -- so-so power, uneven tuning stability & a knocking sound in one at idle.

Despite the close relationship between the engines (cousins), my experience with the Tower 75 (two examples) has been quite the opposite. Stunning power for a 75, easy tuning, good transitions. There will be more of these in my future.

xcarlos

Hi!
I had a SuperTigre G90 and i never had any problems with it.
I think the OS .91 FX-SX, 1.20 AX are very powerful and reliable 2cycle engines at any kind of use (pattern...3D).
Anyway, for a real .90 size plane (like a Funtana S90 about 9 lbs) .91 engines are not really storng enough for unlimited 3D flying.

Gringo Flyer

My Feedback: (18)

[quote]ORIGINAL: xcarlos


xcarlos is right, for a 90 sized plane to have unlimited 3D it will need something more than a 75 or 90. I have a Magnum 90 4S in a 5lb 3Der and its the perfect amount of power. The other 2 3Der planes at my field are both 40 sized and one has a 60 and the other a ST75.

So for rocket like pullout in a torque roll none of the engines will work great on a 90 sized 3Der unless you go for something like a profile.

XJet

My only reservation about the SuperTigre is the problem of mid-range loading-up.

Of the four or so ST90s in our club, they've all had difficulties with the mid-range mixture being too rich.

No amount of carb-tweaking (including rotating the spraybar as per suggestions from the importer) will clear this up sufficient to make them a really good 3D engine.

They're strong and (contrary to what others say) I've found them to prefer smaller props to larger ones.

A 14x6 is about the largest I'd throw on an ST90 and mine certainly prefer a 13x6. Go much bigger and they tend to bog-down a lot and run hot (even after being well broken-in).

For the money they're a great motor -- but just not my first choice for 3D stuff where excellent throttle response and a reliable mid-range are critical to having fun.

Kweasel

My Feedback: (29)

The Tower 75 makes lots of power but favors high rpm with the mini pipe they come with. Supertigre 75 runs and handles as well as any OS 61 I've had, and makes more power. The Supertigre 90 handles bigger props than the 75. The key to the 90 is getting rid of the stock muffler and finding one that is light and free flowing. The carb is relatively small and does not need much if any tank pressure, this also helps with and often cures the mid range mixture problems people complain about.

Marian

Hi Bodge.

Which pipe is that on the photo?

Marian

Bodge

Hi Marian,

I bought the pipe from Just Engines. http://www.justengines.unseen.org/pipes.htm

It is tuned to some extent, but with a wide band that lets it work well for 3D. It is reckoned to give similar power to open exhaust.

The MVVS seems to work well with it - responds to the throttle exceptionally well and is quiet with good power.

Ernie Misner

Xjet and all, do you think the rich midrange of the ST 90 is a function of the carb or engine/porting or whatever. In other words, does a different carb on the ST90 clear up the midrange?

Thanks,

Ernie

XJet

I haven't tried a different carb but I have tried a mousse-can muffler and that made no difference (although it did improve the power level a little).

I strongly suspect that a different carb would do the trick -- but alternative carbs aren't cheap and that makes the whole package more expensive than some of the other options.

For 3D stuff I've pretty much switched to 4-strokes now (Saito). My Mojo 60 with Saito 100 is great fun (and easy) to fly). Sure, they cost 2.5 times as much as a 2-stroke but they have such beautiful transition and instant throttle response that they make you look much better than you are when doing 3D stuff :-)

Kansas Twister

My Feedback: (1)

I'm with Xjet...if it's a 3-D airplane I want a 4-stroke on the nose.

Better transition, more torque and pulling power to get out of jams, and more dependability in hovering close to the ground situations. And I want a throaty sound rather than a high-pitched whine to go along with the aerial ballet.

For a .60 size airplane I would go with a YS-63 or Saito .72-.82; for a .90 size a Saito .100 or .125. The O.S. engines are too heavy and not as strong as a similar Saito...I've used both. Just my opinion of course; I am not trashing O.S. engines and have several...

Jimnie

Hey,
Saito 100 was perfect last year but now we have the FA-125, same size, same weight, big prop! You want 3D with low noise get the FA-125a. No pumps, no pipes, just fly it.
Jimnie

XJet

Well the SA125 is at least two ounces heavier and $60 more expensive so I figure the SA100 still has some life left in it yet, especially when you consider that the 100 makes a nice engine for overpowering some smaller planes and that, in the same situation, the 125 would be insane :-)