Anyone know if there is a drop in replacement for the YS 61 longstroke?
thanks, Tom

O.S. MAX-61 VF

The O.S. MAX-61 VF is a high performance engine that has been developed expressly for FAI Pattern Competetion. It employs Schnuerle scavenging and a rear exhaust port to facilitate the installation of a tuned silencer system, especially where the latter is to be built into the fuselage.

This engine features specially developed ABC type piston/ cylinder construction and a 17 mm O.D. crankshaft of heavy duty alloy steel in order to provide extra power and durability and is equipped with an O.S. Type 7D carburetor, specially designed to give good throttle response.

SPECIFICATIONS

Displacement……………9.95 c.c.(.607 cu. in.)
Bore.....................24.0mm...(.945 in.)
Stroke..................22.0mm.…(.866 in.)
Practical R.P.M…………2,000 ~ (17,000 r.p.m.)
Power output………....…1.8 PS (17,000 r.p.m.)
Weight………………………….528 g (18.6oz.)


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Schpankme

“Take every chance you dare, I’ll still be there, when you come back down.� - Nickel Creek

that's a duct fan motor, I need more of a pattern/longstroke motor.
thanks though

The VF is not a ducted fan engine, VFDF is. VF is a FIRE for pattern planes, like a small 1.40 RX.
Point is moot however, as VF is long discontinued.

Do you need it to be rear exhaust? If side exhaust is OK, Henry Nelson makes a .65 that is very strong running. Call him, he can tell you all about it. I love mine!

Jett also makes engines in both FIRE and FISE configurations that are available tuned for low rev torque.

Good luck!

The OS .61 VF is a high reving engine completely unlike the YS .61 which is much happier turning large props at 9500 - 10000 RPM. The OS .61 RF w/pump was more similar to the YS .61 in terms of performance.

John

Yeah, the Hanno was the best 61 made in my opinion with the RF a close 2nd.

I was foolish enough to sell my Hanno before I ever had a chance to run it.

John

What about the OS Max 61SF ABC-P #17712. I have one new in the box that goes to my unflownen Tipo. The YS and the #17712 are the engines that everyone ran for pattern in the late 80s. I’m not sure if the length and motor mount is the same but you could change that. They sold a bunch of the #17712s and there should be some new ones around.

I had 3 Hanno's and all 3 were the same. Crank 'um up, adjust the high end and fly. NEVER had a minutes trouble out of any of the three. And they were strong! I had the Hanno pipes also that made a difference.

I think the Hanno was built on the #17712.

I think you're right. What a sweet motor. I wish I had one in this Desire instead of the YS.

The Hanno pipe was nothing more than a red 10 cc Hatori long chamber.

John

Probably so, but it looked soooo cool!

Anyone have the "specifications" for the OS MAX Hanno 61 RF ?


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Schpankme

All I know is that they were a 61 longstroke, don't know specifics. Would turn big props and had a lot of low end torque.

Hanno specs in response to Schpankme:

Bore 24 mm
Stroke 23 mm
Practical RPM - designed to run arouns 9500 rpm, but most ran them at 10,500
Weight - a little north of 19 oz without header (they are ABC, not AAC unless you got an aftermarket piston & sleeve)
Prop - APC 12 x 12, 13 x 10, 13 x 11
Pipe - OS sold anodized read pipes that were the same as Hatori 650 at first, then changed to Hatori 700 (better)

These motors were hand built, and each has a unique serial number on the mounting flange. There were two versions, Mark I and Mark II. The Mark II is a little stronger. I have heard about unlimited vertical in an 8 lb ship. I have one currently in a 7 lb ship and it has unlimited vetical.

Hope that helps.

The Mk II used a ringed piston instead of ABC. Unlimited vertical in an 8 lb. ship isn't too tough. But, I will not argue the Hanno was THE engine in pattern in it's day. Even the YS 61 AR was just slightly down in power compared to it.

John

Continuing on with the suitable replacment idea for the YS 61.

MOKI 61 LS RE

SPECIFICATIONS

Type: Single cylinder, 2-stroke cycle, Schnuerle scavenged, ABC with ring, air cooled, glow ignition

Bore: 23.Omm (.9055 in.)
Stroke: 24.Omm (.9448 in.)
Displacement: 9.975cc (.6085 cu. in.)
Compression ratio: 7.46:1
Horsepower: 2.20 Ca) 17,500 rpm
Weight: 17.6 oz. - with muffler 23.4 oz.

Length: (back of case to face of prop driver) 3.60 in.
Height: (Mounting lug to top of head) 3.290 in.
Width: (Mounting lug to mounting lug) 2.350 in.
Crankcase Width: 1.655 in.
Mounting bolt pattern: 28mm x 51mm (I. 102 in. x 2.008 in.)

Manufacturer: Moki Model Engine Co., Budapest, Hungary

Prop: Moki 61 Long Stroke

11 x 7.......12,800
11 x 8.......12,100
11 x 10.....10,300
12 x 6.......11,600
12 x 8.......10,300
13 x 6.......11,100
13 x 8.........8,200
14 x 6.........9,000


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Schpankme

sorry there's no Pic of the Engine with rear exhaust

I just bought an OS 91 off ebay. So I'm gonna sell both the YS 61's as soon as the new diaphrams and plungers get here.

I'm glade you made your choice, it will be interesting to read the out-come of your Desire (91) Build topic, with the conclusion on how she flys.

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Schpankme

Just to answer the starting question. The Enya 60X has the same bolt pattern as the YS 61 but the front is a tab bit short.