klord125

I have a NIB FS26 OS. I was wondering are these things dogs? I see they don't make them any more?? Also what size and style plane will work with it. Any info would be great. Thanks Ken

soarrich

My Feedback: (98)

I have one in a 50" Cub. Dog, no, but it has the power of about a 15 two-stroke, you just don't see a lot written about this size plane. This size plane apples to guys on budgets and it's not a budget engine.[]

klord125

I would like to put it into Bipe. I don't know whats out there for plans or a kit .15 size?

BMatthews

I'm not sure that they even make the same power as a .15 sport two stroke. But it's close. What they DO have in spades is a lovely sound, easy starting and charisma oozing out of every opening.... or is that just the crankcase vent spewing oil....

A 34 to 36 inch lightly built biplane along the lines of an antique or old timer/big rubber model would be an excellent choice for this engine. A hot little Pitts style sporty aerobatic model not so much. It's just not that sort of engine.

A WW1 scale model built up with all open frame construction to around 36 to 38 inch wing span would be a SUPERB combination. Or any number of between the war light scale designs like a Gypsy Moth or Tiger Moth.

If you could find and lighten up the old Flyline kit of the Great Lakes biplane that would be another nice option. Most of the kit is fine but it's got some BIG AND HEAVY hunks of plywood that it uses for the main structure that could be replaced with some lighter options. ALong with a few other changes and this could be a superb option for this engine.

Like you I've got one of these fine little character engines. I just haven't put it into a good home yet.

One option that I've thought about is to take the Sig free flight Cabinaire and turn it into a biplane. Or alternatively take the biplane Customaire and put the "inline engine" nose from the Cabinaire onto that design. But really either path would lead to the same results. I'd then blow it up to double or just a little smaller, flatten out most of the diheral for ailerons and build it up using a few extra and heavier sticks to come up with a proper looking old timey style of model which is nice and light and would fly with the modest power of the little FS26.

airraptor

My Feedback: (66)

I would say they have the same power as a 15 in med sized planes like 250SQ and bigger. The 26 is around 9.2 ounces with no muffler. Most 15's are around 5-6 ounces.

15's work best on a 7x5 APC for speed planes and a 8x4-8x5 for larger planes
26's work best on a 8x8-8x10 for speed planes and a 9x7-10x6 for most sport planes

My OS 30FS will spin a 9x6 APC at around 16,000

noveldoc

My Feedback: (2)

klord125

I would love to build a Tiger Moth or SE5A to put this in. I just scratched a 52"ws SE5A. It was an English plan and designed real beefy/heavy. I made alot of changes to lighten it up but not hurt the integrity. I'm not sure these set of plans would be the ones to shrink. What do you think of a Sopwith pup or Camel?? I have a set of plans for a Sopwith Pup I think 52-55"ws that I can shrink down.Its all built up but I could probably build it pretty light. Any suggestions? Thanks Ken

airraptor

My Feedback: (66)

go for it. try to keep it 4lbs or less. 3lbs would be better.
Remember keep it light and keep it scale speed and you can use "small" servos and flight gear to save even more. then fly if scale like and have a great plane.

Thomas B

My Feedback: (4)

A silly generalization. I like smaller models and am not on a budget, model wise. Model size is a matter of preference, IMO.

Had one of these back in the 1980s. Great little motor. Not a super powerhouse, but would fly any .19 size model nicely.

Patxipt

I had mine on a Junior 60 and on a .25 trainer. Good match to both airframes, although overpowering the J60

Warren B

The late David Boddington designed a very nice pair of biplanes for the FS 26. a Tiger Moth and a Gypsy Moth.
Both are simple buids for 3 channel, no need for ailerons on these old bipes, they look silly doing aileron rolls anyway, much better a barrelly rudder roll.

I have digital version of the Gypsy Moth, pm me if you want a copy emailed.

ARUP

Yes, those O.S. 26's are awful so mail it to me right away! I'll even pay postage to save you the grief! *wink*
Seriously, they're great little engines. I flew a Curtiss 'Headless Pusher' of own design with one. It had a 48" span. Just think of it... 48" span AND two wings with all those struts and rigging 'wires' (fishing string). That '26 putt-putted' that Curtiss without any problems at all. It's only when I added floats that I realized I was asking too much... it never would unstick but it sure would motor around the lake in tidy fashion!!!! The pilot was articulated to move with the controls, too!

hogflyer

I've got one of these little jewel's too. I've been thinking something like a Midwest Tri-Squire would be a great home for it. It's basically in the same ballpark as something like a Veco .19 power wise, so any trainer in the .19-.21 range, or .15-.19 sport plane should be a good candidate for it.

I've seen the Sig 1/6 scale Cub fly on a Veco .19, so if built light it may work also, but will fly in a very scale like manner. Something like a Craft-Air Butterfly may also be a good candidate.

Arup - That's one sweet looking Curtiss Pusher.

Hogflyer

Trisquire

Did you use a scale float? The full-scale float didn't have step. That would keep it from unsticking.

somiss1

My Feedback: (5)

The TriSquire/OS .26 would be a super sweet combo! The .26 is a great engine-easy to run and sounds wonderful. You have a gem!

woodycubamo

I have a OS26FS and plan on building the Tower Hobbies Taylorcraft and using the 26FS to power it. It is a .20 size plane. It won't be overpowered but should be OK. I built a Seniorita and flew it with the OS26 for many years. The Taylorcraft is slightly smaller and lighter so the OS26FS should be adequate.

Woody

Pond Skipper

I have owned 2 of the .26 and 1 of the original .20 The current new .26 on hand will go towards this project rendering when I get some build time a scratch built. The engine will spin up a 9x6 with authority. I have bought some APC pylon props to eek out more speed. First effort with a 8.75 x 8NN

Boomerang1

A 26? Wow, that's the 'big block', I had the .20!

I had it in a 48 inch scale up of my first control line plane, weighed about 3 pounds.
Same story as the other guys, a delightful engine, just not very powerful. - John.

rcguy59

My Feedback: (8)

I had a pair of the little gems on a TwinStar. No barn burner, but it worked fine. Easy starting, reliable as a stone ax and as mentioned, wonderful sound. Great on fuel, too.

Pond Skipper

This is simple mod for a 10% increase in power about 500 rpm is observed when used with a prop per some tach specs.
I have never used the muffler, fuel draw during acro never seemed to suffer negating the need to use the mufflers pressure tap for the fuel tank.
By doing so you gain additional rpm.
INTAKE MANIFOLD ASSEMBLY FS-26S-C

Ken Kehlet

My Feedback: (89)

I had my OS .26 in a SIG Kadet JR, 63" wing and all balsa. Flew beautiful, plenty of power, easy loops and predictable flying.

Never should have sold it.

Ken K AMA 1528

Pond Skipper

Ode to the 4cy OS 26 Surpass or FS- 26S- you can still find them on ebay 1 or 2 show up per month for sale the one in the pic I bought for 74 dollars. Sourced the original OS engine mount and tru turn spinner. Here is a 300 dpi resolution scale photo taken with my desk top scanner.

As shown 383.6g or 13.53oz
Engine Muffler 268g or 9.45 oz

Mr Cox

The Saito .30 weights around 10oz and is more powerful, so for modern applications you don't need the OS 26.

Keeping thing's oldschool is a different thing, and there the OS .26 seems quite popular...

Pond Skipper

Yes always a reason to buy one -here is some data on both

FS-26S Surpass- Weight w/muffler; 9.45oz (268g) price used $50 and up per ebay.
FS-30S Surpass- Weight w/muffler: 10.4 oz (295 g) price typical new $180

Stock Number: OSMG0830
Displacement: 0.299 cu in (4.89 cc)
Bore: 0.767 in (19.5 mm) - 26 is only 1mm less -18.5mm
Stroke: 0.648 in (16.4 mm)
Practical rpm: 2,500-13,000 Note per specs the 26 is 2,200 - 12,00 and 19,000 rpm FS-26C car version
Output: 0.49 hp @ 10,000 rpm - 26 is 0.41HP
Weight w/muffler: 10.4 oz (295 g)
Weight w/o muffler: 9.8 oz (278 g)
Includes: muffler, glow plug
Recommended Props: 9x6, 9x7, 10x4, 10x6 same for both engines

DaveP

I have one in a 71" Sig J-3 Cub - almost 400 flights so far. Silk & dope covering, 3.75 lbs, one more pound on floats. 10x6 MA prop, 12.5% nitro, 20% synthetic oil. Flies great on wheels or floats!

I've had parts for a Flyline Great Lakes I've wanted to build for awhile, but I'd probably put in a FS20 unless it builds too heavy. These older OS 4-strokes have a choke that's really nice for cowled-in engines.

-Dave