I've narrowed my choices down to 2 engines..........

YS91
Saito 100

I've heard so many conflicting reports it's really hard to make a decision between these 2 engines. I assume they are pretty close on power. The YS has a pump, but at the same time is more expensive and heavier.

The motor will be going in a UCD3D.

I'm looking for Power, realiablity, cost. And am I correct to aaume the YS needs a higher nitro fuel than the Saito?

I need your opinions!

I love my YS 91. I run Wildcat 20/20 fuel - $16/gallon. The engine uses suprisingly little fuel, runs GREAT, and is probably stronger than the Saito 100.

Rick

I have a UCD ,which I now have about 30 flights on,i have a Saito 100 on mine.Theres 3 other guys at my field with the same exact setup..I can tell you this ,the saito 100 is the best running 4stroke I have ever owned,and i've had YS,OS,and everything else in between...its a sweet motor,loadsss of power esp on a 15X6 pro zinger ...I favor the Saito 100 so much that I bought 2 more,1 on my 60 size YA suhkoi & 1 for my cap.my saito 100 is in my opinion more powerful than my 120 saito buy yet only like 2 ounces heavier than the 91.I honestly dont like YS ,i've seen too many guys have too many issues with the fuel regulator system on em,they are too temper mental for my taste.thats just 1 mans opinion tho.


Steve

I tried to select an engine for my current project by asking the RCU community. I got a lot of information, but none that I could really use to make a decision with. Here's what I did.

Open up your spreadsheet and enter the following:
Engine
Engine weight
Engine power
Price of engine
Airplane weight
Estimate of fuel type and consumption

Then, calculate:
Total weight of airplane with engine
Power to weight ratio of airplane with engine.
Wing loading of airplane with engine
Performance value (airplane power to weight ratio per dollar)
Operating cost per year.

Once I did all that, I could quickly scan the data and the winner was revealed.

I would wait for the YS 110, best of both worlds!

Thanks for the info guys. Looks like it's a dead heat.

The YS110 will be nearly $400 which honestly will be out of price range. But I' sure the engine would be sweet.........

By the way, after looking at some pictures of this plane are the wings removable. I've heard people mention something about gluing the wing on. If that is the case there is no way I'll be able to fit it in my car. If the wing detatches then I'll be OK. Can someone fill me in?

The UCD wing is removable. The the stab and elevators too.

David

The wing is removeable. Two bolts hold it on. The stab is removeable too if needed. This is not a small plane though. The fuselage is 68 in. the wing is 64 in. The fin stands up about 15-16 inches (haven't measured it). So it needs some room for transporting. I'm flying mine with a YS91FZ which is plenty of power for me. Pulls vertical out of hover without difficulty. I put the tank over the CG (need to trim out one former) and the throttle servo and battery in the rear of the wing opening. Balances at 5 1/4 inches without any weight on the tail. Great flying plane.

Chris

I am not saying which one of the two is a better motor, but I think the Saito is more suitable for UCD3D. Most people find that this plane does 3D best with CG @ 5 1/2" or further aft. With the Saito 100, it's at 5 3/4" for my set-up w/ three 2-oz servos at the tail, 5-cell NiMH battery above trialing edge, and no wheel pants. Total weight is 7 lb. YS will give you better throttle response than Saito for the same prop. But we can "buy" throttle response by using lighter props, such as Zinger Pro, which is not too bad, only 400 peak rpm less than the APC on a 15x6. However, it's not saying the APC 15x6 @ 9500 is generating 4%more thrust than the Zinger Pro @ 9100. It may very well mean that Zinger Prop, being wider, provides the same thrust @ a lower RPM.

The advantage of YS is that you can put fuel tank at CG and have a consistent CG throughout the flight, w/o adding a pump to the engine. Afterall, if you have to add 2 oz of tail weight, the wing loading is still phenomenonally low. Now, putting a 31oz 1.20 4-stroke is another story, as it requires putting the battery pack at the tail, and make for hot landing due to a high-thrust idle, unless you use the 16x4W prop on the 1.20.

I was having the same dilemma about these 2 engines, until I bidded the Saito on a popular bidding site. That price difference made my choice easy. I'd say if you find a good deal on either engine, jump on it. Hint hint?

A lot of people have bad mouthed the YS91 saying that they have had problems with the fuel regulator. I run 15% Cool Power ($12 gal) in my YS91 and have never touched the regulator screw. IMHO too many "shade-tree mechanics" are messing with that thing which is set at the factory and screwing it up. This is one of the sweetest engines ever produced IMHO.

Amen!