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O.S. FS 40 Marine

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O.S. FS 40 Marine

Post  706jim on Tue Feb 23, 2016 10:31 am

Something different from the usual model airplane engines.
An arguably "rare" 4 stroke marine glow engine installed in a Dumas F31 Trojan cruiser model.

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Re: O.S. FS 40 Marine

Post  OVERLORD on Tue Feb 23, 2016 12:55 pm

That's a nice set up. For a race boat, the exhaust would be restrictive, but for a cruiser as the Trojan, the exhaust pipe might give a deep rumble. Is it yours Jim?
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Dumas F31 Trojan cruiser

Post  706jim on Tue Feb 23, 2016 1:41 pm

Yes, it's mine. I built it in 1988 and had a lot of fun setting up the machinery inside.
The engine exhausts into a water-cooled brass muffler. The three tubes on the outside of the large brass tube provide cooling for the muffler, especially required in that the boat runs with the engine enclosed by the upper deck/cabin assembly. Running at part throttle, the engine would run close to an hour on the 8oz tank in the photo.
It is the sort of boat that children at a float fly meet could run around with little supervision, so it got used quite a bit.
If you look closely, you can see brass tubes leading from the radio box to the carb. One runs the throttle while the other is a remote needle valve adjustment controlled by a third servo.
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Re: O.S. FS 40 Marine

Post  OVERLORD on Wed Mar 09, 2016 7:24 am

Jim, I've seen the 2 control rods. What is the advantage of adjusting the mixture during running? Is it something particular to 4 stroke or has it something to do with the throttle?
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On board mixture adjustment

Post  706jim on Wed Mar 09, 2016 8:04 am

When I first started building the boat, I had purchased a cheap two channel radio to control it. As I got further into the project, I returned the cheap radio and bought a somewhat expensive Futaba 3 EGX which was designed to control racing boats. Lots of bells and whistles including steering rate adjustments, start up throttle function etc. As the radio came with a third channel for mixture adjustment, I included this in my setup just to play with it. The 4 stroke is actually quite forgiving for needle valve setting so this really wasn't used much in my case. However, for an all out racing 2 stroke, this would allow optimum tuning under high speed race conditions.

So, in my case, it was mostly just an experiment. I'm just in the process of changing the bearings and may post a couple more pictures. I had to press out one of the cam bearings after all of the recommended methods didn't work.
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Re: O.S. FS 40 Marine

Post  1/2A Nut on Wed Mar 09, 2016 2:45 pm

Got a running vid on the water, pic of the overall boat?
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Making a new one

Post  706jim on Thu Mar 17, 2016 10:20 pm

Here is a post I put on the Practical machinist forum where guys think up things to do with their engine lathes.

http://www.practicalmachinist.com/vb/schaublin-cazeneuve-weiler-graziano-mori-seiki-lathes/model-engine-modification-using-lathe-mandrel-317809/
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Prototype Surpass 48 marine conversion

Post  706jim on Mon Mar 21, 2016 7:38 pm

The 40 and 61 Marine engines are no longer produced by O.S.

Here is a 48 Surpass I'm converting to marine specs for a friend.



Here's a mockup of the final product. Waiting for new bearings to arrive.

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Shielded bearings or not

Post  706jim on Thu Mar 24, 2016 11:43 am

I'm replacing the bearings in my two OS marine engines. The front crank bearings had a shield on the forward facing side while the main bearings had no shields. As the new bearings came from an industrial supplier and have shields on both sides, should these be removed or just left in place?

FWIW, the 40 marine had unshielded camshaft bearings while the 48 had shields on both sides of the bearings.
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Re: O.S. FS 40 Marine

Post  OVERLORD on Thu Mar 24, 2016 1:59 pm

Jim,

Double shielded bearings are greased for their entire bearing life. The 2RS plastic versions have a bit more friction loss than the ZZ metal versions. Bearings that have a shield on 1 side are not greased and should be greased by an external source.

If you want 1 or both sides to be removed, I would clean out the bearing so it can be properly greased by the fuel. Otherwise, I have no idea what would happen to the grease when left inside the bearing. It would probably dissappear in the engine I guess.

Lieven
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Completed OS Surpass 48 marine conversion

Post  706jim on Sun Apr 24, 2016 11:45 pm



This photo shows the newly converted Surpass 48 and the OS 40 marine it was modelled after.



Here is the engine without the motor mount.
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Re: O.S. FS 40 Marine

Post  ian1954 on Mon Apr 25, 2016 1:33 pm

Jim,

Remove the shields so that the bearings are as original and leave the front shield at the prop driver on.

Lieven is correct that the shielded bearings are greased for life but life will be short at these engine temperatures. Far better to use the oil in the fuel to keep them lubricated and cooler.

The limit for continuous operation with a bog standard grease is 135 deg C (275 deg F) - higher temperature greases can be up to 170 deg C (340 deg F) before the specialist stuff is brought into play. It is doubtful that a high temperature grease has been applied to these bearings and a cooked bearing isn't a pretty sight!

I would also leave the grease on after removing the shields. Just wipe off any excess - it will help the bearing on first startup.

Those engines look superb.
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Re: O.S. FS 40 Marine

Post  1/2A Nut on Mon Apr 25, 2016 2:15 pm

Aaawwwwsum job cant wait to see / hear one running on the water summer time is here
Post a vid when you can!!!

This Site Rocks!
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Re: O.S. FS 40 Marine

Post  1/2A Nut on Sun Aug 21, 2016 10:59 pm

Updates any vid? I have a OS 26 Surpass and bought a flywheel kit for it I want to make
a scale mahogany runabout for it.

I am working on a marine drive too.







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OS 40 marine update

Post  706jim on Mon Aug 22, 2016 12:32 pm

I finally got the boat back together and made its maiden run last week. Hope to post a few pics and video within the next two weeks or so. (Had to repair an old John Deere tractor first but that's another story).

I had planned to marinize an OS 26 but after looking at the main casting, realized that it was not practical. The reason is that the access hole to remove the wrist pin is too high up and would have to be covered by the water jacket ring. The only way it might be possible would be to machine the crankcase, re-install the piston liner etc and THEN shrink fit the brass cooling ring over the crankcase which would essentially make the engine unserviceable. This is not a problem with the OS 40 and larger engines.

I may end up trying the 26 conversion anyway just to see if it could be accomplished as I have the perfect runabout to install it in. But as mentioned, once converted this way, the only way to service the engine (bearings etc) would be to press the cooling ring off of the block; easier said than done!

So, video coming soon.
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Re: O.S. FS 40 Marine

Post  1/2A Nut on Mon Aug 22, 2016 2:47 pm

The car guys mount the RC carb up top for max power unloading over 19k

Yes very tough to do what you have on the other engines but could perhaps
with a thinner brass ring.

Pic for reference:





I have owned two of the .26 and one of the .20 lovely engines.
Bench tested my latest one have not done anything with it as of yet.
I was thinking a cooling fan or a fabricated metal blade fan right on the drive
shaft. Also thought about threading soft brass tube around the fins to water
cool in conjunction. 4 cyl sound on a scale runabout would be a joy to run.



https://www.youtube.com/watch?v=X_2dtx22Zy8


Published on Nov 8, 2015

Bench tested: OS FS .26 Surpass 4 cyl. engine
Master Airscrew 9x7 Scimitar S-2 Prop
10,981 to 11,143 set bit rich as this is a jewel of an engine needs to last.
74 mph static and estimate 12,700 unloaded for 84 mph.
After this run I fine tuned the idle to a steady 3.8 to 4.1k rpm.
25% nitro 14% castor 8% synthetic.
Tru Turn 1.75in Aluminum sport spinner.


Last edited by 1/2A Nut on Mon Aug 22, 2016 3:08 pm; edited 2 times in total
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Re: O.S. FS 40 Marine

Post  RknRusty on Mon Aug 22, 2016 2:51 pm

Some of the stuff you guys do looks dauntingly challenging, but the results, as in the hydroplane video, are as cool as it gets. Thanks for showing us what else goes on with the engines I just bolt on and fly.
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Trojan F31 videos

Post  706jim on Fri Aug 26, 2016 11:06 am

It took long enough, but here are two short videos of my recently restored F31 cruiser powered by the OS FS40 marine engine.



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Re: O.S. FS 40 Marine

Post  1/2A Nut on Fri Aug 26, 2016 2:49 pm

Wow Jim she moves and she putts along great with good sound!
Thank you for sharing looks like a good spot for running der boats.
How much weight is that engine pushing?

Popcorn
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Boat weight

Post  706jim on Fri Aug 26, 2016 6:21 pm

Interesting that you asked about the weight of the boat. I never worried about it compared to various airplanes that have come and gone.
The boat and superstructure weigh in at about 7lb.
While I've never timed the boat, I think it might run around 12-15mph at full bore. I never made any effort to optimize the prop as most of the time it is run at part throttle. I'm running a 6oz tank right now which should be good for 35-45 minutes. Don't know how this compares with electrics, but you can go a long way with that sort of duration.
And, speaking from experience, the most fun you can have with a model like this is to run it from a moving boat. Take it "somewhere" for a trip and let someone else drive. Trust me, it's a hoot!
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Re: O.S. FS 40 Marine

Post  roddie on Fri Aug 26, 2016 7:33 pm

Very cool Jim! Thanks for sharing the vids. I haven't seen many IC engine powered cabin-cruisers. Sterling used to make some nice kits years ago too. I used to marvel at the Chris-Craft scale cruiser models in the model-magazine ads as a kid. The closest I ever got, was building a built-up Dumas DV10 ("Short-Stuff") for elec. power. I also have a Dumas "Atlas Van Lines" hydro kit "semi-built".... designed for .049 Cox power. I'll have to pick Brad's (1/2a nut) brain about a good Cox engine-powered running-gear set-up. He's done some VERY cool boats!
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Re: O.S. FS 40 Marine

Post  1/2A Nut on Fri Aug 26, 2016 7:40 pm

Back when I was 9 to 11 yrs old my next door neighbor in Fla. was doing large scale
boats last effort was a 4ft + tug with a IC engine. I would see projects drying out
in the back yard from initial water proofing to full detailed color paint jobs. Sometimes
he would be out back firing up engines. This was my first introduction to scale boats.

Being scale your example sounds great with a 4cyl. Local boat clubs here want to do
gas powered outriggers, another local club halves up the smaller nitro and elect. efforts.
Yet another club does sail boats. But I have no idea where the scale wood crafted majestic
boats are ran. It was always a treat to hang out with fellow modelers talking shop and
testing the latest greatest, with some BBQ and beer in the works.

I have also had a hankering for something full scale small enough to store in the garage.
At age 15 I did make a all ply mono hull and used a 38cc engine for power it took me
around the pond at a nice steady pace and was a great all around adventure from construction
to finish.

Theses days I'm thinking 1 or 2 large outrunners as the torque is impressive and easy on the
frame of the boat due to the smooth running low vibration characteristics of these types of motors.



Last edited by 1/2A Nut on Sat Aug 27, 2016 12:24 am; edited 1 time in total
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Re: O.S. FS 40 Marine

Post  roddie on Fri Aug 26, 2016 8:13 pm

A custom personal water-craft would certainly be an interesting endeavor.. whether it be for all-out speed.. or a docile craft for staying "reasonably dry" for a slow/relaxing exploration (with camera..) or getting into those great secluded fishing holes at the local reservoir! Speed seems to be more fun though! 40-50 mph is FAST when you're in a really small boat! Jet-skis are great... but they're not really "boats". They're more like "motorcycles" for the water. A jet-drive might be okay.. but I'd want a cockpit, wind-screen and steering wheel! Maybe nitrous-injection too.. Shocked

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Re: O.S. FS 40 Marine

Post  1/2A Nut on Sat Aug 27, 2016 12:24 am

Yes the idea is you can remove the sponsons and aluminum booms the whole thing can be placed in the back of a
pickup truck and stacked on a rack up against the garage wall during the winter.

I use to ski a lot at 20 mph and I can say at 30 mph you are zipping along pretty darn good on the water enough
to cut across the local lake in very short time. Ebay has some crate engines for motor cycles you can snag a  V twin 400cc
for $490 bucks that would be more than enough to run faster than most jet ski as a surface drive prop is superior in speed
per hp / ratio. Really I wouldn't want to do more than 50 mph it gets scary low to the water. The design can be wide enough
to sit two and still hit 35 mph. A three point hydro has a unique sensation as the prop lifts the tail up clear of the water the
speed kicks in like a the hand of God just shoved the craft forward to the next level of speed. Small craft like this is a cheap
way of getting there. Door skin with a fiberglass rap will be plenty strong with 1.5"x 1.5" square stock spruce framing.
Aluminum skid plates under the sponsons and back end will protect from floating sticks and such.

Fishing
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Machining parts for the OS marine 40

Post  706jim on Thu Dec 15, 2016 1:12 pm



Posted this in RC groups when discussing cam bearing removal in 4 stroke engines.

That lathe is just a little overkill n'est ce pas?
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Re: O.S. FS 40 Marine

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