ameyam

Hi,

Right before the OS 91SII was discontinued, i had obtained a 91SII & its remained my silver bullet- absolutely reliable even after i did an overhaul. Then, i came to know it was being discontinued & picked up another

Years passed by & i never ended up using the 2nd engine. I then moved to gas & the 91sii that was working became a off-season flier & the other remained NIB. Now the opportunity has come to pass off the NIB engine

I just want to cover my bases in case i need a similar size engine again & i know the 95 has replaced the 91. Need to know feedback regarding the 95. Its no alpha series engine, i know tge alpha series has much more power.

How is the 95 4c engine against the 91sII reliability & powerwise?
Ameyam

the pope

Theres a couple at our field and there good runners . I know they made a few manufacturing changes to cheapen the cost of the engine and i heard recently at the club that the 110 alpha is no longer , the thing that stopped me getting one was theres no breather to squirt afterrun into .. If it was me I would keep the 91 you can get bearings anywhere and a ring ( theres a guy on the forums making rings now )even though Frank Bowman doesnt make them anymore . Cheers the pope

ameyam

Hi pope,

actually, I have a 55ax, 65ax, the in use fs91, another fs91, 95ax, 72A and 110A with me. Out of these the 55, 65, one 91, 95ax, 72a are NIB and the other 91 and 110A are in non regular use. The Alpha series are really strong engines and the 110 was easily hovering a 4kg Reactor biplane. All these engines were horses for races but I have since mobed on from those races (sold off many of the airplanes those engines were for)

Thing is, I also have a Dle 20, Gt22, Dle30, Dle35ra and a GT33. In the last two seasons (ours is from October to May, so it is about to come to an end) I have been flying almost entirely gas. The 20 is unused and the 22 is NIB meant for a plane that's also NIB. The 30 is on a Funtana my buddy is flying and I am flying his 35ra on one of the two 35cc airplane I have air worthy.

The point I am making is I have a good collection collated when I was into glow a lot. I need to unload the same now but I need to keep some cover for a rainy day. Talking of rainy day, the monsoon should start mid June, from then, all the larger airplanes will be out of the question and the one 91 I have will be used. Hence I really need to consider giving the NIB 91 away.

If my in-use 91 conks off, I could end up having to get the 95, hence just needed to know if the engine is as much of a gem as was the 91

Ameyam

Hobbsy

My Feedback: (102)

I think you'll find that the .95 will be the more powerful of the two, it's prop recommendation starts where the .91 leaves off. I am going to get a .95 at some point and I'm confident that the mfg. processes have been streamlined and material quality has not been sacrificed. That's my take anyway. My Alpha .56 is exactly on par with a Saito .56.

the pope

Some points that may sway your decision. Remember this is not a critisisim but if your an old fart like me may make you prefer the older version .
Here goes
1- no bush on the conrod little end
2- the valves sit in the alloy head ie no bronze insert
3- the rockers are held in place by the rocker covers only.The pivot shafts are free to move sideways and would fall out if not for the covers . Me no like dat

Are these enough for me to not buy one , no . This is the one thing that anoys me about OS . They have 3 different styles of 4 strokes going at one time . The Alphas , the fs v's and the surpass all going at the same time . Saito only change the crankcase and can box cover . One last thing you call your 91 a gem so you must like it a lot so never sell my gems although l have recently and regretted it . I sold a OS 55 ,supertigre 40 and a LA 46 just to get some expensive servos and it was a mistake emotionally although it makes good fincial sense because I still have more engines than I can use and I'm going bigger . Cheers the pope

ameyam

Hi pope,

I spent the equivalent of USD225 on the engine but the guy who wants one is at 155USD. However with the airplane and its accessories included, the total additional cost was just USD 60 more, so he decided to go with it. Thing is, there is no real requirement to hold on to the 91 because I don't fly that size much now. Once you go gas, there is very little glow work you can take. My glow engines are now just for part time non-serious flying or for flying my less valuable airframes. Even in that case, I still have the 110 and I can always get a 95 if I need it.

With regards to the construction, I saw similar setup on the 110 except for the free rockers part. Can you snap that and send?

Ameyam

Hobbsy

My Feedback: (102)

I ordered a .95v this am, will report.

the pope

I dont have this engine but I do have the surpass II 72 OS . I got my info from a review in the aussie airbourne edition 241 mag , it show pictures as well as stating the info I provided in the text . Cheers
PS i guess I could scan the pics if u REALLY need it but please dont make me L.O.L.

ameyam

No, I will check out the pics on the net, don't worry

Ameyam

Hobbsy

My Feedback: (102)

Thankfully the .95v has a crankcase vent

ameyam

I meant a pic if the engine with covers open as The Pope informed. Anyway..b

Ameyam

Hobbsy

My Feedback: (102)

Pope is correct about the rocker shafts being held in place by the rocker covers, they are not likely to fall out on their own. Mine is arriving today in the big brown truck,

ameyam

Irrespective of whether they fall out or not, that some spectacular casting.

Anyway, I saw what I wanted in that pic. Remaining details will come from the manual

Ameyam

Jim Schwagle

My Feedback: (1)

My 95 is somewhat more powerful than my Surpass II 91. It runs and idles well, no problems (on 15%) and performs close to my better Saito 100. ( I have two 100s. One is somewhat of a poor performer, more like a 90, the other is powerful and it's easy to see more power than a typical 90.)

Hobbsy

My Feedback: (102)

A couple of interesting features on the .95v, the vent is cast integral with the crankcase, top dead center is marked on the prop driver. I will run it in a day or two and report. The first thing I did was to remove the two JIS screws that hold the carb and replace them with M3x22 socket head screws.

yyk1966

My Feedback: (3)

Same is the back pressure nipple on the muffler. You will probably need a fuel line clip to hold the tubing securely. I had a couple of dead stick landings because of back pressure tubing came off.
Later I replaced the "new-style" muffler with an old style from OS FS91. I think old muffler better matches the vintage look of the 95v engine.

Hobbsy

My Feedback: (102)

Thanks for the Tip Off, I hadn't even unwrapped the muffler yet.

dwmcmike

just got a 95 last Friday. It's on a Hog Bipe I've had for a few years, that previously had a Saito 100 GK on it. The Saito is headed off for some bearings and a look-see / overhaul, and will hopefully be back in the Hogs nose before too long. But we'll fly it for a while with the OS 95. So far, i've run 2 tankfulls of fuel through it, Powermaster 10% / 18% castor/syn oil, following OS's instruction sheet of running it lean for a few seconds, then opening up the HS needle a full turn to cool it down. Turning a 14/6 TopFlite power pro for break-in, I may try to run a 15/6 xoar that I used to run on the Saito on the same airframe.

So, once the wind calms down enough that I can actually go fly the thing, i'll be able to tell you how the OS compares to the Saito on the same plane. So far, the break in running has gone very well. The engine is exceptionally smooth at idle, transitions well to WFO even with a minimum of break-in and from a casual observation appears to be a very well-made engine.

Everything is out charging right now in the hopes the wind will be something less than 15mph tomorrow.

Hobbsy

My Feedback: (102)

I just spent 90 minutes breaking in the OS .95v, I must have nailed it, it has some fierce compression.

Engine===OS .95v
Fuel=====Wildcat 2/4 with 18% full synthetic
Glow Plug=Taipan 4c
Prop====Xoar 15x6

I hit a glitch while peaking for max rpm, as I passed through 9,250 the tack went black so I laid the tach aside and proceded to set the LS needle.While I did that the battery made a brief recovery and I got see a beautiful 1,950 rpm idle. I will seek more top end when I get a new Tach battery. There is one oil stain on the muffler and another on the left upper corner of the back plate. It's a keeper for sure.

dwmcmike

Had a few days of decent weather, and quite a few flights on the bipe with the OS95. Compared to the Saito 100GK, this engine pulls a lot better in verticals. Granted, the Saito had a couple of seasons on it, but it never pulled this hard. I've probably run 10-12 tanks through it on the plane now, so breakin is about done. Idle is great, starting is easy, and it sips fuel. It gets high marks from me, being one of the better 4-strokes I've ever owned. Just to fill you in, it's turning a 14-6 Zinger and is fueled with Powermaster 10% nitro / 18% oil castor/synthetic blend.