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Old 11-08-2011, 12:10 PM
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Yeah.....I think I'm gonna have to keep my Inverted torque rolls down to under a minute.
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Old 11-08-2011, 03:24 PM
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Guys; The dry clunk syndrome is something we MUST solve before next season.
Clear water bottle tanks are no way to solve it, and clunks wrapped in felt simply release broken fibers directly into your carb screen.
Header tanks sound like a good idea, but twice the stoppers, twice the tanks, twice, the plumbing, and 30+% more weight kind of scares me.
What are we going to do?
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Old 11-08-2011, 03:27 PM
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How do they set up the tanks on real aircraft?
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Old 11-08-2011, 04:20 PM
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80's ROCK RULES
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Quote:
Originally Posted by jlloyd1995 View Post
How do they set up the tanks on real aircraft?
High Wing aircraft like Cessnas are vented gravity feed system from the wings. Low wing (Cherokee style) have engine driven pumps and electric Aux pumps. Aerobatic real aircraft have the typical inverted fuel and oil system. Most real aircraft don't fly extended downlines. The Citabria and Decathlons (High Wing aerobats) use gravity feed like a Cessna, but also have a large "coffee can" looking tank can down by the pilot's feet to allow fuel draw while inverted.
There have been a few full scale aircraft use a clunk system, but they don't appear to be too common. Since full scale AC are 4 strokers, they need the oil pump shoot oil up onto dry parts when inverted.

Ronster is a full scale certified mechanic; maybe he can add to this ....
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Old 11-08-2011, 04:24 PM
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Just another IMAC prima donna
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Quote:
Originally Posted by djmille View Post
Guys; The dry clunk syndrome is something we MUST solve before next season.
Clear water bottle tanks are no way to solve it, and clunks wrapped in felt simply release broken fibers directly into your carb screen.
Header tanks sound like a good idea, but twice the stoppers, twice the tanks, twice, the plumbing, and 30+% more weight kind of scares me.
What are we going to do?
OMG!!!!!!!!



Just a shameless response to drive my posting count up
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Old 11-08-2011, 04:55 PM
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Originally Posted by divad View Post
I thought about trying a filter clunk, but it was only to filter the fuel. It doesn't work with a 2 line system. For some weird reason I like hairless better anyways
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Old 11-08-2011, 04:56 PM
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Having rebuilt and riveted together several tanks on both cessna and pipers.
They are gravity fed systems. There is no clunk on almost all Cessna's That's all the way up to the 210 Centurion series. The do have a plumbing and pumps to transfer fuel from one wing to another to even things out. Its basically a Bladder that is rolled up and squeezed through a large oval sealed inspection plate.

On the Piper 140-180 series the inboard wing bays ahead of spar are really gas tanks. You have to rivet them together and seal it up the with a epoxy sealant. The tank is actually screwed to the airframe. Once again no clunk there is a low point in the corner of the tank with a screen affair that allows you to connect a hose to it. Pumps and valves are used to get the fuel to the engine.

Typically aerobatic aircraft do have inverted systems.
Example you might see like on a Pitts would inverted oil and inverted fuel system.
I do know on some of the tanks are baffled to prevent fuel/oilfrom sloshing around.
On the Pitts its just one fuel tank that resides ahead of the pilot near the cabanes. I do not know if it has a clunk or not?
I did fly in a Super Decathlon with just inverted fuel only. It was reecomended not to sustain long period of invetred flight.

I have ran the fiber clunks and never had a problem.

I really think it is not an issue to be concerned about. The header tank will work and the fiber clunk will work. Heck if your worried about the fibers gettin loose just put a filter in the fuel line to the engine problem solved.

You could always put a little slack-ness or a mild curve in the fuel line on the way to the motor and achieve a little more time for a down line. For you unlimited guys having to draw long down lines
at idle I don't know.

I did try some designs back in the 80's that didn't work, to try and get the clunk down to the front of the tank but were fruitless. I had an idea of putting a pendlulum type swing weight on dubro smoke valve but could never get to seal up right and work quite right. I know it was Just an idea.

Ronster
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Old 11-08-2011, 05:07 PM
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What about vapor lock? When you start winding the fuel line around in circles, there are many more bubble opportunities.

What does Miranda think ?
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Old 11-08-2011, 05:20 PM
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This might have been from vapor lock?
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Old 11-08-2011, 05:44 PM
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cuttin the grass with balsa
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Quote:
Originally Posted by RoughLandin View Post
Um, I really don't want to see DivaDave's hairless clunk.
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Old 11-08-2011, 05:48 PM
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Um, I really don't want to see DivaDave's hairless clunk.
That's good! But I think this has one
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Old 11-08-2011, 06:21 PM
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On a more serious note:
As far as full sacle applications of inverted fuel and oils sytems - it does vary.

Christensen makes an inverted fuel system that has a header tank. This does seem to be the predomanent method of inverted fuel. It is sustainable for around a minute or so of inverted flight.
Others use what they call a flop tube " This method is also used in some of the oil systems as well."

I can see Darin saying in his mind "He said Flop Tube - that's cool Beavis heh heh heh eh".

Ronster
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Old 11-08-2011, 06:38 PM
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Quote:
Originally Posted by divad View Post
That's good! But I think this has one
Hey, that's a picture of my girl friend who thinks I'm a stalker. She's not really my girl friend......yet.
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Old 11-08-2011, 06:53 PM
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There isn't any kind of valve that only pulls in liquid and not air, is there?
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Old 11-08-2011, 07:01 PM
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Um, I really don't want to see DivaDave's hairless clunk.

Yeah, I hit submit before I thought that response through all the way. I was just excited that I could finally use that graphic. LMAO

At least Divad came back and clarified to help us visualize what he was talking about.
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