toucano

I have an OS .91 Four-stroke is mine. I've tried APC 12x13, Zinger 12x13, 12x10, and 12x9 and 14x7-13 (what does 7-13 mean anyway?) If I wanted the plane to go as fast as possible, what prop would be the best?

twister

My Feedback: (12)

I have a shoestring with a 91 fs 4 stroke and i have found that a 13X10 works really good for top speed and a 14X6 for lots of vertical . have to say i love the way this bird flies!!!

toucano

Twister -

I think I settled on the APC 11x13 for speed, but I'll give your 13x10 a try. There's nothing like a flight box of 50 props that just aren't right!

Yak18

My Feedback: (11)

What do you experts recommend for an OS 61FX on the Shoestring? Mine is fast with the APC 13-6 but you know, let's see how fast she'll go!

Yak

autopilot

Got my Shoestring up for the first time today, and it flies great. A friend trimmed it out for me - maybe two clicks on aileron trim & and two on elevator, and it was hands off after that. I was wondering about flaps, but it lands fairly slow - just don't use the last third of the runway for the touchdown. It's QUICK. I've got a Magnum 61 2-stroke in mine with a Pitts muffler, using a 12X6 wooden prop. Also, it looks good in the air & on the ground, as I got compliments from everyone at the field.

Mettler1

Ya know, I hope that quotes like this don't surprise too many people, we are dealing with a RACER here. The SHOESTRING is one of the few planes that you can expect to come out nose heavy. Stick a big .91 fourstroker in it, and it's going to be even more nose heavy. All of this means, that you are going to need to add more weight to the tail to make it balance !

Result - You made the little plane overly heavy, and it's going to result in SURPRISE, higher landing speeds. Put a lightweight 2 stroke .60 engine in. It will require no extra tail weight to balance, and it will land as slow as a butterfly with sore feet. [/B][/QUOTE]

Actually, if you check Tower's web site you'll find the OS 61fx and the OS 91fs with mufflers installed weigh almost the same. The 91fs actually weighs slightly less by a tiny amount.
Rather surprised me!! Two stroke mufflers weigh more than 4 stroke mufflers. :surprised

rc-sport

My Feedback: (12)

All the reports and reviews I've read all say the same thing, with the OS61 and a Pitts muffler no tail weight was needed. I installed that same combo and had to add about 4 oz of weight to the tail. I added a Sullivan fueler but it doesn't weigh that much. I don't even have the wheel paints installed. I installed a Bisson Pitts muffler maybe it weighs more than others, Beat me. Oh well its still fun to fly.

Ed_Moorman

My Feedback: (1)

One of the replies mentioned using a "heavy" .91 4-stroke. The Saito .91, an AAC engine, weighs, according to their specs, 18.3 ounces with muffler. The OS .61FX is 19.4 ounces. I would imagine this is without muffler, but it is still an ounce heavier than the "heavy" Saito. Other 4-stroke .91s are much heavier, especially the Thunder Tiger at over 26 ounces.

Mettler1

Ed, according to the Tower web site the OS 61fx weighs 23.6 oz. with muffler and the OS 91fs weighs 23 oz. with muffler.
So it's not a question weight about as it is about fitting in the cowl and type of power and sound you want. Just bought a GP Shoestring and am pondering which engine to go with.
I really like the sound of a four stroke in a scale-like plane but the OS 61fx will fit entirely inside the cowl with a pitts type muffler. For me it's a tough choice to make as I like both engines.

tmproff

My Feedback: (5)

I had a .91 Saito in mine, and was a very nice match for the plane.

carlbecker

My Feedback: (3)

I just took my shoestring up for its maiden flight. OS 91 surpass, inverted 14x6 zinger (light) and trueturn P51 spinner. No need for more motor. Fast agile and slows down real nice for landings. I use a 5 cell pack and hitec 225 servos. CG right on with no extra balance weight. I don't think it makes a good second plane but I really enjoy it.

ShoestringRacer

Just curious as to why it does not make a good second plane. Do you mean it is too much performance and it should be considered as a 3rd or 4th plane or are you just not pleased with it in general???...just curious

Yak18

My Feedback: (11)

I wouldn't think it's a good 2nd plane for these reasons;

1. It's fragile. It will not take much abuse. If you blow a landing you will blow out the landing gear and that will take the bottom of the fuse off...major damage.

2. It's fast. Three times faster than a trainer which would have been your 1st plane.

3. It's neutral. Not self righting, you fly it from takeoff to touchdown.

In a nutshell, you have to be a very competent pilot to enjoy flying it. It's not hard to fly if you know what you are doing. I know when I was on my 2nd plane I did not have the experience to successfully fly an airplane with the performance of a racer.

my .02

Yak

tmproff

My Feedback: (5)

I agree....the 2nd time I flew mine, I blew out the bottom of the fuse.....fixable, but he is very correct..this is quite a delicate plane. The entire bottom fuse is ribbed in less than 1/4" balsa, very easy to break this.

Flyguy1791

My Feedback: (4)

Mine has been complete for sometime, still trying to FIND the engine that will not tip the nose over.
I have a few NIB engs. First try was a Tigre Shark .75 figures not much more bigger than a >60... Now I'm gonna try the ASP .61 and see how that goes...

Thing is : CG is right on the money at 3 & 3/16 " from edge and inside stuff moved back as far as possible . Third try is a charm, I hope..

Has anyone else had problems like this ?
I have been flying for many years and never had to add weight to the tail area..

Tony

rc-sport

My Feedback: (12)

I have an OS 61 in mine and it never tips over, sure you have the gear in the right way?

Yak18

My Feedback: (11)

Some people have been mounting the landing gear backwards in ERROR and this causes the airplane to nose over.

The Shoestring has a long nose so you must push all your radio gear to the back of the radio compartment to get it to balance.

I have my switches and receiver behind the servos and my battery is in the turtledeck behind the trailing edge of the wing. With this setup and the OS61FX with Bisson Pitts muffler, it balances on the money and has never nosed over even in the long grass I fly off of.

Yak

P.S. This airplane is one of the best flyers I've had in over 30 years of flying.

poorbs

My Feedback: (3)

If you move the CG back a little and set the controls for a higher rate, this airplane will tumble and do many hot dog maneuvers, and with a computer radio it will knife edge forever (better have dual rates because it does snap with "over" control). If you read the directions, you'll notice that it calls for tail first landings - a landing on the mains results in a bounce. It slows nicely with no tendency to stall. Most people don't read far enough in the directions to notice that you don't need longer bolts for the aileron horns. You just harden the wood with CA and put wood screws into it - it holds just fine - the directions tell you how. Jim is right about being nose heavy with a larger engine. Keep it light and it will fly and land like a dream. I had to install the battery under the stab and run a wire to the front in order to balance it - but no additional weight was needed with an O.S. .61 FSR. It likes to nose over sometimes, so the most vulnerable part for me is the cowl. Try replacing the metal cowl screws with 4-40 nylon ones - easier to replace than the cowl from vibration.

twister

My Feedback: (12)

had a mishap with the shoestring on a dead stick landing it bounced off the runway and stalled into the bushes what looked like a cushioned blow turned out to be a torn off firewall!!! If you can some how strengthen the firewall with more glue do it cause i noticed a lack of glue on the firewall once it was apart. It is now re epoxied and flies like a champ with my O.S 91 4 stroke!!!!!!!

Ed

I duct taped my battery pack to one end of a piece of light ply the width of the pack, and maybe 7"- 8" long. Then I slid the pack down into the fuselage, and anchored the "stick" at the front with a screw, at about the trailing edge of cabin.

Jim

chuckgaudette

I've had similar experiences to what some other Shoestring owners have reported. I built the plane with the OS 61 and Pitts muffler but had to add some tail weight. I cracked one of the very delicate stringers in about my first hour of assembly and another picking it up after a dead stick landing. Surprisingly on the dead stick from about 15 feet high it landed a bit hard but level and no damage. The only thing I've had to do which no one else has mentioned is to shim the motor slightly down. At high speed it climbs even with 5 or 6 clicks of trim and then when you reduce power it dives. It sure is a pretty sight however on low high speed passes.

carlbecker

My Feedback: (3)

I have a OS 91 surpass in the nose. Its a little heavier than the 2 strokes but I use a 5 cell battery pack mounted as far back as possible and a light wooden prop. The CG came out fine. This plane needs a light engine up front. Its not real hard to have it balance proper if you plan ahead. Put 5 flights on it this weekend. Big loops and inverted flight is pretty good - does exactly what you command it to. Not bad in a cross wind either. Really happy with it.

T28pilot

My Feedback: (2)

Mine Has a SuperTiger .61 in the nose....balance is perfect....never noses over....Smokes the Shoestrings with the Saito 100's in Them.....Just a overall Great flying plane....looks kool.......goes fast.....seem to do aerobatic with the rest of them....how could u ask for more?.......i give mine 2 thumbs up

Flyguy1791

My Feedback: (4)

Well,
Just put the ASP .61 on the front and ran a tank thru. Same problem sooooooooooo,.

It seems when building this or any other plane , I try to take my time and things go smoothly , 98% time. I finially figured I would take the wing off, undo the darn landing gear and look to see what would happen if I turned things around..

Sure enough, landing gear looks like it leans forward more.
Well it seems when you think you did everything right and don't need to undo everything , turns out the fellows here in the forum were right on the money.

It looks like I'll gain another 1/2 for sure and boy is it close....No excuse though. I can't thank you all enough,

Been a long time coming.
Can't wait to fly it.

Thanks again,
Tony

rc-sport

My Feedback: (12)

Thank you...Thank you very much. ( taking bow)