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Thunder Tiger Raptors 30-90 - Imperio > inverted flameout ! tank flow - help?
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

hi all - I had a very intense R/C experience today. I was practicing inverted hovering at about 100' up when the engine flamed out. I managed to push it over and auto it well enough to keep the bounce less than a foot. really high pucker factor. G3 has once again paid for itself as I was just starting to practice inverted TH-HOLD to recover.

Anyway, the engine died from lack of fuel. The header tank was less than 1/2 full even though the main tank was 1/4 full. With the header clunk line being about 1/2" it pulling from the middle of the tank. In normal flight I can drain nearly every drop before any air gets in the header tank.
My first guess is that the clunk line in the main tank is too stiff so when inverted it doesn't get near the top of the tank.

Anyone have any suggestions to get all the fuel out of the main tank inverted? Also, is it possible to do a dual clunk line/uniflow tank setup with the TT tanks?

...yep...
08-03-2006 Over year old.
 
 
unklpunk
Senior Heliman
Location: alberta canada

i have had similar issues,.. i believe your right with the stiff line not letting the clunk move freely to the top/bottom of the header tank,.. a more flexable line will fix the problem.
08-03-2006 Over year old.
 
 
SPB
Elite Veteran
Location: Athens - Greece

Or maybe it's too long and stucks in the wall of the tank.


Sotiris
Sponsored by Greekrotors
myhelis.com Flying Team
08-03-2006 Over year old.
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

Actually, they may be too short. I was very concerned about the possibility of the clunk sucking up against the back of the tank so I made the line sit something like 3/4" off the back of the tank (main) and pretty short in the header tank, figuring it'll always be full.

...yep...
08-03-2006 Over year old.
 
 
BOOGIE
Veteran
Location: LAFAYETTE LA

what is the best clunk line to use?
08-03-2006 Over year old.
HOMEPAGE  
 
 
TH-67Guru
Senior Heliman
Location: Daleville, AL-USA

same thing happened to me on my rappy 30. I initiated an inverted auto and the G's pushed the fuel back and i recovered, I cut mine to where its barely maybe 1.8th of the back of the tank when the tank is verticle. slap it all around to make sure it doesnt hit the back of the tank, also do the same with ur header tank. I use the clear stuff at the LHS, its just the right stiffness
08-03-2006 Over year old.
 
 
bmcgrady
Senior Heliman
Location: Sylacauga, AL

Also check and make sure the fuel line hasn't gotten soft. If it's the stock line that comes with the tanks that stuff is pretty bad about getting soft... almost to the point of being "jelly". That causes the line to actually collapse and restrict fuel flow, which will kill your engine.

Anyways, just something else to check...
08-03-2006 Over year old.
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

I used the pink Prather med. line on all my plumbing.
Is there a more flexiable line that would not collapse like the TT line? One to use specifically in the tanks?

...yep...
08-03-2006 Over year old.
 
 
BOOGIE
Veteran
Location: LAFAYETTE LA

Ricks has this clunk line
http://www.ronlund.com/Merchant2/me...&Category_Code=
08-03-2006 Over year old.
HOMEPAGE  
 
 
Wa11banger
Elite Veteran
Location: Huntsville, Al

Hayes is the ultimate clunk line for normal clunks. I have used it for years.. It swells so make sure to cut it approximately 1/4" to short so it has room to grow.. It will do this within the first few flights or with some beating maneuvers.

Do not use if you have a fuel magnet, The fuel magnet for some reason (weight once wet?) will tear it within very few hard manuevers.. Use parther or med blue line with fuel magnets

In normal clunk tank even with muffler pressure 6- 8 months longevity has not been uncommon for me.

Rick

Proud member of the Quick UK, Duralite Flight Systems, V-Blade, and K&B Dream Designs Teams
08-03-2006 Over year old.
HOMEPAGE  
 
 
spog
Senior Heliman
Location: Ontario, Canada

If you're not running a uniflow tank setup, the engine usually leans out when inverted. Another benefit is that the engine gets very rich when the main tank runs out of fuel.
08-03-2006 Over year old.
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

how do you run a uniflow with the TT tanks?

...yep...
08-03-2006 Over year old.
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

As the sun was setting last night I held the Titan upside down against the sun. The main tank clunk wasn't even half way down to the 'top' of the tank.

Moral of this story, make sure the clunk moves around in the tank! The pink Prather line may be great at resisting nitro abuse, but it's too stiff for the clunk line! I appreciate the link to the clunk line BOOGIE.

...yep...
08-04-2006 Over year old.
 
 
kcass518
Veteran
Location: Manhasset, NY - USA

Is that Hayes clunk line made of neoprene? How does it stand up to CP30%?
08-04-2006 Over year old.
 
 
Wa11banger
Elite Veteran
Location: Huntsville, Al

kcass518,

It stands up well, CP 30% was all I used until last year. I check mine every 90 days, I end up replacing it roughly every other inspection and not very often because it failed. Unless as stated above with a fuel magnet I do not run it with them.

Proud member of the Quick UK, Duralite Flight Systems, V-Blade, and K&B Dream Designs Teams
08-04-2006 Over year old.
HOMEPAGE  
 
 
BOOGIE
Veteran
Location: LAFAYETTE LA

How about this http://www.ronlund.com/Merchant2/me...&Category_Code=
08-04-2006 Over year old.
HOMEPAGE  
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

I like this, thanks man - options!

I'd be concerned about 'small' fuel line causing a higher flow resistance resulting in tuning changes as the heli flips around and/or the fuel level goes down. This is the reason I usually don't use the Hanger-9 fuel line that comes with their ARF's, ID is too small for my liking.

Thoughts? Anyone running the small AER1011 line as a clunk?

...yep...
08-04-2006 Over year old.
 
 
spog
Senior Heliman
Location: Ontario, Canada

A uniflow setup requires a new tank plug with two tubes instead of one. I used brass rod, with two holes drilled, and brass tubes jb welded in. It's a pain in the butt, but well worth it IMO.
08-04-2006 Over year old.
 
 
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Thunder Tiger Raptors 30-90 - Imperio > inverted flameout ! tank flow - help?
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