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Cox Engine of The Month
January-2018
crankbndr's

Mercedes-Benz W196 with a 350-3 .049 Engine



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Recent engine acquisitions

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Re: Recent engine acquisitions

Post  1/2A Nut on Thu Nov 30, 2017 9:23 am

Thank you, I bench tested with the standard plastic back plate I want to try something like this next.

Pressure tap idea working on it..

It can also just be mounted to the fire wall and the stem is
cut to butt up against the fire wall and be blocked off from
air intake keeping the reed closed. Of course you could just fill
the stem up with JB weld.



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Last edited by 1/2A Nut on Thu Nov 30, 2017 2:40 pm; edited 2 times in total
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Re: Recent engine acquisitions

Post  MauricioB on Thu Nov 30, 2017 9:31 am

Interesting !, in the way you show in the photo, you would be pressurizing (sending pressure) to the fuel tank, which would allow you to have a constant flow of fuel! .... It's a good idea, you have to see what happens in the practice!
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Re: Recent engine acquisitions

Post  balogh on Thu Nov 30, 2017 9:37 am

1/2A Nut wrote:Thank you, I bench tested with the standard plastic back plate I want to try something like this next.

Reed for a one way valve controlled pressure tap. :brows.

It can also just be mounted to the fire wall and the stem is
cut to butt up against the fire wall and be blocked off from
air intake keeping the reed closed. Of course you could just fill
the stem up with JB weld.



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Brad,

an interesting combination, but with the reed valve closing when the crankcase is pressurized, how will you pressurize the plastic tank through the venturi?


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Re: Recent engine acquisitions

Post  1/2A Nut on Thu Nov 30, 2017 2:25 pm

I spoke too soon after thinking about it, the reed will not regulate pressure.
Piston goes down is when the reed would need to be open and that is not
going to happen.

Can fill the void with JB weld with a very thin oiled steel wire centered when filling it up.
After 65% cure time slide the wire out for the pressure vent. I plan to use a guitar string
the lower light gauge steel E string (.3M). Hope to improve fuel flow when pulling straight
up out of a down wind passes and hard turns.

The fire wall with have a ply ring  that protrudes into the back plate cavity so the engine gets
more bite with the back plate mounting screws. The TD .020 will be screaming much more thirsty
may go with 3/4oz tank.
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Re: Recent engine acquisitions

Post  1/2A Nut on Thu Nov 30, 2017 7:33 pm

Ok the solution was easy using some small oil spray extension tube made from hard
plastic worked, the hole in the tube is .35mm. I used 20mm length of it to extend
the pressure flow restriction. The throttle sleeve will reduce pressure at idle which  
should help it from going rich, full throttle NV setting should be interesting to see if
the engine picks up some more rpm over that last test. OD of the red tube is 2.1mm.




Can use this one with no pressure tap about the same weight.



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Re: Recent engine acquisitions

Post  Jason_WI on Mon Jan 01, 2018 6:26 pm

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Re: Recent engine acquisitions

Post  dckrsn on Mon Jan 01, 2018 8:18 pm

Jason_WI wrote:Blind squirrel found a nut in the woods.
https://www.rcgroups.com/forums/showthread.php?3011680-Vintage-Nitro-Engines
Nice"nut", Jason. Good way to
start the new year. Clapping
Bob
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Re: Recent engine acquisitions

Post  Oldenginerod on Tue Jan 02, 2018 3:39 am

Great pick up. Lots of potential there Thumbs Up
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Re: Recent engine acquisitions

Post  Marleysky on Tue Jan 02, 2018 8:56 am

Yeow! You’re starting the New Year on the right foot! I see a bit of cleaning and polishing in your future! Nice find for sure!

Fireworks
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Re: Recent engine acquisitions

Post  Surfer_kris on Tue Jan 02, 2018 2:41 pm

Here is my latest purchase, an un-used TT .25 engine for about $25. Smile
I have another one that's a real sweet runner, and these are very lightweight for their engine size too.

I'm really glad that I checked the inside before running it though. It turns out that it needed a bit of "de-burring" inside the crank... affraid





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Re: Recent engine acquisitions

Post  KariFS on Fri Jan 12, 2018 8:39 am

Kris, What the...? Is that left from the machining of the induction channel or has there been a reduction bushing or something inside the crankshaft?

Here is my very latest acquisition. No motor on it but still somewhat related. A few weeks (or months) ago I answered a poll about our hobby and won this:



It is the "ELF" by Vladimir's Model in Ukraine. Wingspan is 39in, flying weight 3.35oz. It is called a DLG, which means "Discus Launch Glider". A sort of a hook is installed on the left wingtip and the plane is launched like a discus. Plenty of videos on the 'tube.

It is handcrafted, materials are a bit exotic to me. Carbon fibre wing structure, thin plastic radio compartment and the tailfeathers look like they are 3D printed.



I'll need to get some very small servos, a micro receiver and a 1S LiPo receiver battery. Probably need to move on to GHz technology, I doubt there are any receivers available that would be tiny enough and compatible with my existing 35MHz gear.
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Re: Recent engine acquisitions

Post  MauricioB on Fri Jan 12, 2018 8:52 am

Surfer_kris wrote:Here is my latest purchase, an un-used TT .25 engine for about $25. Smile
I have another one that's a real sweet runner, and these are very lightweight for their engine size too.

I'm really glad that I checked the inside before running it though. It turns out that it needed a bit of "de-burring" inside the crank... affraid






Ohh affraid ! I'm surprised, I agree with KariFS will be a reduction bushing? ... I'll grotesque that piece of metal so that it has arrived from the factory like this!
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Re: Recent engine acquisitions

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