I am currently building a Sig Somethin Extra and am ready to put the engine on.

I have 2 engines laying around (Saito 91 and an OS 46FX) and thought that I'd get your guys input before I did it.


My questions start here. I am confused about what engine to use. I have a strong suspicion that the OS 46 does not have enough power to pull this plane around, though I am worried that the Saito 91 is too heavy. Now here's another problem. Experimenting with both engines (before I mount one of them) it looks like this plane does not have enough clearance for a prop bigger then 12". Which leads me to wonder if a 12" prop will over rev the Saito.

If I use the Saito am I limited to using a 3 blade prop, due to the lack of ground clearance?

Has anyone used a Saito 91 on this plane? How does it perform , what prop are you using and how hard was the plane to balance?

Thanks

Kev

The 46 will pull the plane around,but not unlimited vertical,the Saito should give unlimited vertical,mine at the present time has OS 70 FS,has limited pull out in hover,plan on changing to OS 90 FS when I finish some other building projects. To get prop clearence I use taller wheels,if that fails I change to taller landing gear and or wheels.

!! a Saito .91 on a SE !!

Well, let's see.

With the stock landing gear you'll be lucky to use props over 11". 12" can be managed if you make *very* short takeoffs and only three-point landings. Yuo will break a lot of props, though.

You'll have to use a steeply-pitched prop in order to load the engine properly. I run a Saito .91 on my WM Mustang, and have had great luck with an APC 11x12 prop.

It will be difficult to balance, but not impossible. I've read reports here from people that have used OS .70 four-strokes on these - the big Saito only weighs 2 oz more.

OK!
Now that I've said the above...

Don't do it!

If you put that Saito onto your SE it will have the flying characteristics of the Space Shuttle. Great vertical performance... very fast... not terribly forgiving on landings...

This plane is meant to be kept light! A good .46 is sufficient, if propped correctly (for thrust, not speed.) This plane works really well with big diameter low-pitched props - try an 11x5. If you replace the stock shorty gear with the taller one sold by TNT you'll have plenty of clearance for up to 13" props - at this point you can try a 12x4 or 12x5. You can also use a tuned muffler to bump the performance up a bit.

FYI - I have a YS .53 4C on my SE and the previously-mentioned taller landing gear. This engine weighs about the same as a .46 2C but swings 12x6 and 13x5 props with authority. This is a Wonderful combination - lots of power with low wingloading. Its like a butterfly

Depending on what kind of flying you plan to do, the OS 46FX does a really nice job on the SE. I have this engine in both of my SEs, and one is on floats. I haven't flown that one yet, but feel it will handle well. I won't be doing much "stunt flyin'" (Have you seen the movie Flech with Chevy Chase?) due to the floats.

I agree that the 91 will be awfully heavy for such a light plane.

Why add un-necessary weight like a four stroke?

That airplane flys WONDERFUL! on an a 46!!!!!!!

If that doesn't do it, add a dose of an O.S. 60fp for some great fun!!!!!!!

Yeah I know, what do I have against 4 strokes, well, if they just didn't weigh so much, and didn't sound like fart machines!!!!!!

Have fun!!!!!!!

I test flown today my third somethin extra
my first one had an os 70 four stroke
my second one had an os 60 two stroke

this one has os 46 FX and is really funy
the .70 version was nose heavy and needed big wheels for prop clearance
the .60 two stroke version was overpowered for me.

the third one fly great in the flight envelope it has been designed for with the .46 fx

here is a pic of the third one

Ill Second the 46 but I would go Thunder Tiger, if you have a 46FX buy yourself the TT 46 Muffler what a difference on the OS 46, a lot more power.

Thanks
Mike Badger
www.Aero3D.net

Heres a pic of mine:

Well, I've flown mine with an OS 46FX, Magnum 52 stroke, and a Saito 72.

I have to say the Saito is the best, but for the pleasure of flying such a great model, an OS 46FX was easily enough. SEs aren't for 3D, but for graceful, very predictable aerobatics, which an OS 46FX is quite capable of providing.

The Saito version:-

Thanks for the info everyone.

I was thinking all along that the 91 would be a little too heavy and probably to much power..I just wasnt sure.

I think I will stick with the 46 and call it a good. At this moment, I really don't want to spend more money on a new engine, but in the future I'll probalby throw a 61 on it and see how she performs. To answer the question above about what type of flying I'll be doing with it. Probably just very minor aerobatics, but mostly pleasure flying.

Hmm....guess I gotta find something to use the Saito 91 on. Any suggestions on a good Arf to put this motor on?

Kev

The Saito 91 would be perfect in an Ultra Stick.

I'll leave the choice of whether to put it in a 40 or 60 size, as I have just been very silly, and put an OS91FX in my 40 size US.

<eg>

David C.

the U_CAN_DO3D

Another opinion...

I am just finishing up the SE ARF. I built the kit several years ago. It was an okay airplane, but just didn't do much for me. I had an OS 46 SF on it. All in all, a nice model; but rather ho-hum.

Then I flew a pal's SE ARF with a YS 63. This airplane was MADE for four-strokes. With a big, low-pitch prop, the stump-pulling thrust of a good four-stroke makes the model come alive.

Okay, all of this is subjective. I am in the process of getting rid of every two-stroke plank engine I own; going strictly to four strokes.

For me, the much greater thrust and acceleration of a properly-propped four stroke just beats ANY two-stroke on any day. YMMV...

I will say that the Saito 91 is probably a bit much. But it has been done, and as long as you give yourself some more prop clearance, it will work. Do a search for TNT Landing Gear Products. They make a custom SE gear that gives you the necessary clearance. You have to drill your own holes; big deal.

Steve

The .46fx works great on the SE. Kid at the club has one with the .46 and a 11X5 prop and can hover with it all day long. Several with the Irvine .53's and these are even better. Real stump pullers.

I currently fly mine with a saito 56. I purchased the 91 also with the means of putting it on the sig. I did and it would about shake that thing to death. The tail was moving about 1/2 side to side! Everthing was balanced too. i don't use a spinner on mine. So the prop had to be balanced. The Saito 56 is a great engine for it. it doesn't give it unlimited vert, but it will pull hard, using a 12.25x3.75 apc. I have another that I need to cover that is going to have an os50sx on. That should be a great combo.

In other words, if you have the 46fx use it.