Re: 3D printed beam mount .049 backplate

**944_Jim** Thu Oct 17, 2019 8:26 pm

Jason_WI wrote:I need to find my 1/4-32 tap or order a new one.

Used to be able to buy the AP .061 carburetors pretty cheap and run a 1/4-32 die on the mounting base to put threads on for use on a TD. The source for those has dried up.

Nah, you just need to be creative!
I happen to know a jovial guy that loves to fly CL, has no interest in carbed AP .061s, has a few AP .061s that he'd like to convert to Cox TeeDee venturies, and would probably trade out these AP carbs as long as it means his APs could pull a CL plane around just fine using Cox venturies. Huh...

And he lives in the SouthEast US...and knows an adapter can be turned out to fit the AP engine with enough meat to allow internal tapping/threads for the Cox Venturi.

For that matter, start talking Norvel, and I bet he would part with Norvel carbs for venturies too! Fishing

You want me to point him to you?

PM me so I can put you onto him!

Jim in MS Eyebrows

Jason_WI Fri Oct 18, 2019 1:50 pm

Still 3 left for testing yet.

I have one of each carb type for testing. I won’t need anymore for that. Thanks for the lead though.

Jason_WI Tue Oct 22, 2019 5:52 pm

45 degree angle rear intake for Tarno or Cox TD RC 05 carbs.

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dckrsn Tue Oct 22, 2019 6:09 pm

Jason_WI wrote:45 degree angle rear intake for Tarno or Cox TD RC 05 carbs.

...or a TeeDee venturi/valve body?
Bob

Jason_WI Tue Oct 22, 2019 7:03 pm

dckrsn wrote:
Jason_WI wrote:45 degree angle rear intake for Tarno or Cox TD RC 05 carbs.
...or a TeeDee venturi/valve body?
Bob

Yes

getback Wed Oct 23, 2019 7:17 am

Jason_WI wrote:Still 3 left for testing yet.

I have one of each carb type for testing. I won’t need anymore for that. Thanks for the lead though.

Have these been tapped ? I don't have one that size , but do have carbs. R/C for TD .049 and would bee interested in testing one of the difft. styles Small Cox Logo

1/2A Nut Wed Oct 23, 2019 8:52 pm

Yes very suitable will allow less of a beam mount cutout on the fuselage and access to the intake for prime!

Small Cox Logo

**944_Jim** Wed Oct 23, 2019 9:50 pm

Ummm, Jason,
Idea #1:
Could that manifold flange be built a little longer so just a needle valve could be across it?
Then the needle valve would be off-center from the crank, but not necessarily need a Tee Dee Venturi. Something like a Medallion venturi sticking out to the side.
Idea #2:
Any chance you could print an all-in-one venturi/adapter for my AP engines to take a reedie needle valve as if I cut a Medallion venturi off and stuck it in the AP? (Another potential commercial endeavor there)

Jason_WI Wed Oct 23, 2019 11:01 pm

944_Jim wrote:Ummm, Jason,
Idea #1:
Could that manifold flange be built a little longer so just a needle valve could be across it?
Then the needle valve would be off-center from the crank, but not necessarily need a Tee Dee Venturi. Something like a Medallion venturi sticking out to the side.
Idea #2:
Any chance you could print an all-in-one venturi/adapter for my AP engines to take a reedie needle valve as if I cut a Medallion venturi off and stuck it in the AP? (Another potential commercial endeavor there)

If I make the intake longer then it would be very difficult to print. It has to print with the reed area upright. Would need a raft then. With nylon it needs a solid footing on the bed plate otherwise it will warp like a tater chip.

Not sure on option 2. I might have an AP .061 to use for a pattern on the intake.

Here is how the 45 degree needs to print. Blue green is the support material.

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KariFS Thu Oct 24, 2019 12:58 am

These are SO cool! And probably scaleable to .020 size too, right?

I like the idea of it being interchangeable with Medallion/Tee Dee, it opens all kinds of possibilities and options for adjusting the engine power and CG.

1/2A Nut Thu Oct 24, 2019 3:17 am

Yes could do with the .020 and use TD Venturi / NV or ...... NV and printed air choke for throttle.

Really the air choke can just be just two parts / the barrel and the body as anyone should be able to fined a servo arm
and screw & tap the barrel for the control arm. Don't need a set screw to guide the barrel stop as the servo can be trimmed
to do that chore. So this makes it possible for .049 and .020 next a manifold / header to control the goo and you have a friendly
engine on the ears and faster clean up between flights.

Small Cox Logo

Jason_WI Thu Oct 24, 2019 4:41 pm

Here are the 45 degree backplates printed. As you can see with the natural Zytel the right one in the picture warped pretty bad. I have 2 more printing out of glass fiber reinforced Zytel. The glass and carbon fiber version Zytel filament are more stable during printing.

I have to find my 1/4-32 tap or order a new one to tap these for tarno/TD venturi use.

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1/2A Nut Thu Oct 24, 2019 4:53 pm

Looking good via proportions should be a winner!

Popcorn

getback Thu Oct 24, 2019 5:33 pm

I have to find my 1/4-32 tap or order a new one to tap these for tarno/TD venturi use. Lookie Lookie Very Happy

Jason_WI Thu Oct 24, 2019 5:53 pm

getback wrote: Lookie Lookie

You haven’t seen my basement.

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Jason_WI Fri Oct 25, 2019 2:46 am

Glass fiber reinforced Zytel. Here it is mounted to one of my customized engines. Tarno placed for now as I need to order a 1/4-32 tap.

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1/2A Nut Fri Oct 25, 2019 3:12 am

Painting a good picture, are those beam bore holes the same dia. as what's on a TD?

Popcorn

getback Fri Oct 25, 2019 7:19 am

Now that's a basement Pumpkin

I bet it is Brad , as soon as that tap get there you'll find the other , at least that's what happen to me with a oddball one i had gotten for a .020 TD prop screw/crank. Doh!

Jason_WI Fri Oct 25, 2019 8:58 am

1/2A Nut wrote:Painting a good picture, are those beam bore holes the same dia. as what's on a TD?

Yes the hole pattern on this is the same as a TD.

Jason_WI Mon Oct 28, 2019 1:09 am

1/4-32 tap arrived.

Tarno installed. Hopefully get a chance to run it this week.

M

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1/2A Nut Mon Oct 28, 2019 1:54 am

Looks tough enough to handle the power. RC carb is well in the clear for ease of use.
Should be a real treat to run.

I have prepped a .049 for testing will use a Galbreath / Nelson plug adapter and a
vintage engine that has zero run time. #2 cylinder / 2 bypass ports and 1 flute per port.
Thick wall with single large exhaust ports.

Pumpkin

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1/2A Nut Sat Nov 09, 2019 7:07 am

This would work great for CL profile planes, plenty of influx with a TD venturi / NV.
NV is easy to get to and clear of the exhaust blast.

Hex head screws would be a nice touch and a bit longer then what was used here.

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getback Sat Nov 09, 2019 8:13 am

Look Good Brad Very Happy

Got to get off my but before it gets too cold to run anything ! Cold

27F this morn.

1/2A Nut Sat Nov 09, 2019 11:01 am

Yes Eric nice little twist makes it all more fun, I will be bench testing a handful of configurations.
This was fast to set up so will go first. I will be using a muffler to keep the noise down.
Jason has done a great effort to make this beam mount part very suitable for CL use and throttled RC!

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ticomareado Sat Nov 09, 2019 3:26 pm

Now that's some serious hot rodding. A hybrid semi-plastic Space Hopper

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