Hi all,

I recently bought a Harrier 3D. Love the plane but the powerplant - an OS 91FSII 4 stroke using a 15x4 prop (turns at about 9,000 rpm) just doesn't seem to be enough - it can hover but at full throttle and I'm not comfortable with that. I have tried a 16x4W prop but the OS will only turn that at 7,000 rpm. I have tried a 14x6 and 15x5 but neither of those worked well. For fuels I have tried powermaster 10%, 15% and 20% and have noticed little difference.

So my question is in two parts

1) Does anyone have any suggestions around the current powerplant/prop/fuel combinations.

2) For those that suggest I try another powerplant what would be your recommendations. I was thinking of getting a YS1.10 but they seem to be hard to come by. Does anyone have a 2 stroke running in this plane that they find works well? What about a Saito 1.00.

Any suggestions appreciated.

Ian

The Saito 100 on a 15x4 APC is will beat the OS 91 for power --which is where you are in trouble.
BUT---The OS91 will run on lots of nitro and should be propped for 10000 rpm for best power - you need to open the stinger on the stock muffler as much as possible
We went thru this engine years back and found that basically it is a terrific design -which is seldom used at max power setup
So my own advice is to open the muffler --buy/borrow 30-40% Heli fuel - get a 14 x4 (aprox) prop and try again
Also ditch all purty up weight such as spinner wheelpants -use a good 800 ma high amp battery -etc.

ys 110 just blast your way out the os 91 will never give the power it takes

Dick,

Thanks for your response. Will try the nitro - is there a particular brand that has worked for you? On the muffler - I am just using the stock one - is there a better muffler on the market I could use.

Ian

how would an mvvs .91 or mvvs .77 2-stroke work on this plane????

Also, what about an OS 108FSR (BX1). If not, what is the best 2-stroke for this plane that is $230 or under???

Xanatos, i have the Harrier 3D too and i'm just gonna wait until the ys 1.10 are in stock again. I think the last shipment for the ys1.10 came in already and sold out..maybe you can oder now and be put on a list but im not sure if they even have a waitng list.

Do you plan on flying it soon cause you don't live far from me and it's cold out not to mention we are getting alot of snow right now. I don't plan on flying until april/may, at least it will have warmed up some.

There is a waiting list for the YS110. I fly the Harrier with an OS91 II and have had great results wit a 15X6 APC and 30% cool power. It could use more power but, will do whatever I tell it.

How bad do you want a NIB ys110 ...I know where I can get a couple....JW

I am glad i have had a NIB YS 110 just waiting to go into the Harrior, now if i can find time to complete the plane. I would highly recommend the YS 110. I had one on a UCD 3d and with a 16'4 wide blade it was aweswome, with Wildcat 30% Heli fuel.