HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 21, 2004, 05:42 PM
boo!!
Decrash's Avatar
Dallas(metro), TX
Joined Nov 2003
131 Posts
O.S 49-PI rotary wankel

Does any have one of the (overly expensive) engines? How do they compare? Are they easy to start?
I am most likey gonna buy one, I heard they have the power of a .45 but have the gas consumption of a .60 size.
Decrash is offline Find More Posts by Decrash
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 22, 2004, 02:22 PM
boo!!
Decrash's Avatar
Dallas(metro), TX
Joined Nov 2003
131 Posts
Doesn’t anyone have one of these?
Decrash is offline Find More Posts by Decrash
Reply With Quote
Old Jun 23, 2004, 06:14 PM
Registered User
Joined Mar 2004
186 Posts
The only Wankel I have seen is the OS 30.
I have a new one never flown.
I was told it has closer to a 40 power but uses the fuel of a 30.
Mine has been carefully bench run and it has a very cool sound.
Sorry but this is all I can tell you.
silverwing is offline Find More Posts by silverwing
Reply With Quote
Old Jun 24, 2004, 05:29 AM
It flies? I like it!
Joined Apr 2004
867 Posts
Drinks fuel, sounds neat, a bit low on the power to weight ratio (heavy for the output). Definitely a cool toy but not a better mousetrap.
Lomcevak is offline Find More Posts by Lomcevak
Reply With Quote
Old Jun 24, 2004, 04:57 PM
Registered User
Tony Oliver's Avatar
North-East England
Joined Mar 2002
3,397 Posts
OS Wankel

If you get one, don't dismantle it without being very careful to keep a record of where the gearing was before you took it apart.

I was given the parts of one a few years ago to clean and assemble. It's a fiddly job and a time consuming one at that.

Lousy photograph from an early digital camera but here it is. Motor ran well for its previous owner but it seems they need good cooling.

An early one owned by a club member caught fire in the air and destroyed a VK Cherokee - 'is that some film come loose?' reply 'It's not film, it's flames! The ********** things on fire'

Do you remember the old cream plastic cased servos? The ones in the Cherokee looked like well chewed mints after the heat got to them. The engine lived to fly another day.
Tony Oliver is offline Find More Posts by Tony Oliver
Reply With Quote
Old Jun 25, 2004, 12:26 AM
Suspended Account
Everett Wa.
Joined Jun 2001
5,925 Posts
The Peripheral Intake of the OS Wankel Motor 4.9cc is a very nice piece of work. The weak point is that the apex seals have to run over an interrupted surface and if over spun may catch in the port. This is very rare. The other concern is that there is a great deal of temperature differential across the end plates. In larger engines this can be addressed with side seals on the rotor. On these small engines OS has used a plasma spray coating that has been machined out of flat so that when hot it is flat (built in warp). Many engines are destroyed during “rebuild” as the builder (destroyer) try’s to lap the side plats flat. The fasteners need to be torque very slowly and in a cross over pattern so as not to upset the side plates.
As for the operation they are hard to start relative to a ringed Veco engines. Power is the same as most 2 cycle high performance sport engines of the same displacement. The rub is that the displacement of a Wankel is hard to measure when compared to a round peg in a round hole type engine. They are a lot easier to muffle that a 2 cycle engine. They do NOT respond to a tuned pipe. The carb is out of date as it is an air bleed type. Converting to one of the twin needle carb found on some of the higher-powered 2 cc car engine would be a wise upgrade. Fuel burn is the same as an open faced (no muffler) 2-cycle engine of the same power output. The OS likes small props and high RPMs 16K to 18K. I like mine as a novelty item (it is only one of two OS engines I’d own). It does run well just needs a starter to start; this in my opinion is a flaw for a “sport engine”. If you want power in this class range (price) look a the YS 45 (7.5cc), Rossi 45 (7.5), the Jett or Nelson sport class engines .40 cid (6.5cc) to .50 cid (8cc). To place on your mantlepiece or in your collection the OS is a great engine!
Konrad

P.S. The photo above is of the OS 30 Wankel. It is not the PI 49 as witnessed by the side induction. This motor is a classic circa 1979.
Konrad is offline Find More Posts by Konrad
Last edited by Konrad; Jun 25, 2004 at 12:39 AM.
Reply With Quote
Old Jun 25, 2004, 02:18 AM
Registered User
Tony Oliver's Avatar
North-East England
Joined Mar 2002
3,397 Posts
Sorry about that Konrad.

I omitted to make it clear that the motor I was commenting on was the .30

Tony
Tony Oliver is offline Find More Posts by Tony Oliver
Reply With Quote
Old Jun 25, 2004, 11:27 PM
Suspended Account
Everett Wa.
Joined Jun 2001
5,925 Posts
No apologies needed, you were factual in saying that this (photo) was of an old OS Wankel. I just wanted to point out that not all OS Wankels are the same. Side induction vs. peripheral induction on a Wankel is about as different as loop scavenging vs. schnurle scavenging on a 2 cycle engine.
Konrad
Konrad is offline Find More Posts by Konrad
Reply With Quote
Old Jul 14, 2004, 03:43 PM
Registered User
United States, MI, Commerce Charter Township
Joined Dec 2000
1,296 Posts
I believe the .49PI and the .30 are the same motor, perhaps after OS took over the motor and removed the cooling fin.

Dave
Dave Campbell is offline Find More Posts by Dave Campbell
Reply With Quote
Old Jul 14, 2004, 05:39 PM
Suspended Account
Everett Wa.
Joined Jun 2001
5,925 Posts
Dave.
Both the .30 cid and the 4.9 PI are the same size engine. They have both always been made by OS. OS bought the license from Graupner who holds the licensse from NSU for all engines that are 10cc or smaller. Graupner never made the motors that OS makes. Graupner did make a Wankel but do to a mathimatical error it was bigger than the OS. The Graupner and the .30 OS Wankel are side induction type engines. The newer OS 4.9 PI Wankel is a Peripheral Intake (PI) design. Side induction verses peripheral induction on a Wankel is about as different as loop scavenging vs. schnurle scavenging in 2 cycle engines.
Konrad
Konrad is offline Find More Posts by Konrad
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold OS 49-PI wankel jrplane Aircraft - Fuel - Engines and Accessories (FS/W) 0 Jan 09, 2006 05:36 PM
F/S - O.S. .30 Rotary 49-PI Wankel – NEW Style IA-Flyer Aircraft - Fuel - Airplanes (FS/W) 0 Sep 18, 2004 06:17 PM
O.S. .30 Wankel, N.I.B. for sale Ranald Aircraft - Fuel - Airplanes (FS/W) 3 Feb 23, 2003 12:55 PM
O.S .03 Rotary Wankel Input wanted Cuda Engines 4 Dec 29, 2002 08:43 PM