avicom

My Feedback: (14)

Hi I'm trying to make this clunk work properly in this tank but I can take it any more. What I'm doing wrong here. The tank stopper hole is too high and the tanks lengh is too short. Even with the brass tube in L shape the clunk will not run to top and bottom of tank. I don't want my fuel system to get air during flight. I remember too many people arguing by this type of tanks and manufactures still doing the same. What a pain in ..........![:@]

Regards
Alex

rhklenke

My Feedback: (24)

Does it sit vertically like that? Also, is there a 3rd tank in the background that I see? Is this a setup with two saddle tanks (the narrow ones) and a mian tank? If so, don't worry about the clunk in the saddle tanks too much. Just get it into the fuel when the plane is upright and banked at a reasonable angle (like when making circuits). The main tank will act like a bubble trap and if its large enough, it will drain the saddle tanks dry before it, itself empties...

Bob

avicom

My Feedback: (14)

Bob, this is the smaller tank, and is sit in that position in front of the intake. The other tank in the background is the main one and is sit on top of the intakes over the small tank. I can try to make the system to drain fisrt the smaller one. But I'm afraid to drain the fuel because gravity force knowing the bigger tank will be on top of the small one and over the vent line. I got no problem with the main. Look the configuration of tanks. This way they will look in tha plane.

rhklenke

My Feedback: (24)

I would absolutely make the system drain the smaller tank first. If the tank with the clunk problem is also the smaller tank, you are all set. Just fit the clunk towards the bottom like I said and plumb it into the larger tank. The larger tank will "filter" the air bubbles coming out of the smaller tank and you'll get almost, if not all, of the fuel out of the smaller tank. There is no problem with the first tank to be drained being lower than the other. In the Flash, the main tank is in the upper fuselage and the wing tank is in the (low) wing, at least 6" below the main tank. The wing tank empties first and mine is always bone dry when I land...

Bob

DelGatoGrande

My Feedback: (23)

i agree with Bob.

...but your L idea is also right...
only you must add +1/3 lenth more so to alow the clunk to chase the fuel and have less brass tube in the tygon
so to alow more flexybility

again you can open a hole in the midle of the tank as you say to use and fill the aper one!


or use after this tank a smaler tank and then the UAT!

http://dreamworksrc.com/catalog/prod...roducts_id=588

...again better if you drain first the small tank

or you replace it! with two smaler ones to its place!!



good luck!

Kevin Greene

My Feedback: (85)

BVM sells fuel line that is more flexable than Tygon---Also, Neoprene would work too..

Kevin

avicom

My Feedback: (14)

Thanks bob,

In that case I'll set up like you said. My only worry was making a spill during fuelling. Because the main who is the big and top one will push the fuel to the small one wich is the one with the vent to the bottom of fus. But if work in the flash it should work in my dragon also.[sm=wink_smile.gif]

Alex

Kevin Greene

My Feedback: (85)

Here is a link to the fuel line that BVM sells that is more flexable and is for inside of the tanks...

http://www.bvmjets.com/Pages/fuelcells1.htm#KA

Kevin

afterburner

My Feedback: (18)

I can attest to this as I've seen bob fly the Flash for over ten minutes with no problems and complete full circuits inverted. As a matter of fact, I've seen Bob land with ALL the tanks bone dry including the UAT.

Marty

cactusflyer

My Feedback: (4)

Bob,

I'm a little confused by that statement. Where do you think that the fuel is in a coordinated turn of say 30° , 45° , or 60° banks?

John

avicom

My Feedback: (14)

Thanks to all. I will do as Bob said. The clunk in the small one will stay in the bottom at all time at least and plumb it to the main tank wich is on top a la flash and to the UAT. Still have about one more week of work before test flight.

Happy Thanksgiving
Alex

rhklenke

My Feedback: (24)

John, In a coordinated turn, its in the bottom of the tank, level, *but* its hard to tell if a turn is coordinated from the ground and most guys tend to fly circuits with the wing towards them down a bit even in the straights, so its unlikely that the fuel is level all of the time when flying a simple circuit...

Bob

cactusflyer

My Feedback: (4)

Correct Bob.

I hear some fairly "aero-dramatic" theories though at the flying filed! I would say that if the jet has a gyro, the turns are coordinated. Aditionally, if the jet "looks right" in the turns...that is to say nose level with the horizon , not low or high, the jet is in coordinated flight. Not sure about the one wing low circuits....Unless some rudder is added, it is flying an arc.

I used to fly a Saberliner and the procedure to balance fuel was to open the cross flow valve between the wing tanks and gently step on the heavy-side rudder............It works!

Tailwinds,

John

jetnuno

Hi

I went thru the same problem. 2 saddle and one main tank. I am using tygon and wheighted the original clunk -12gr. Also I think that tight bends do not help a proper feeding in large turbines, so since I will use a P160, I decided to machine my own clunks. I machine 30gr cluncks from brass and now these are able to go up and down freely because the tygon stiffness is overcomed by the clunck weight.

Now with the hard G manouvers my clunks will brake the fuel tanks

Nuno