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Twinstar Need bigger tanks

Old 12-06-2009, 09:41 PM
  #1  
DougB1
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Default Twinstar Need bigger tanks

I know it is over kill but I have 2 O.S.52 4 strokes laying around that is going in my new Twinstar. Has anyone tried putting a larger tank in the fuse and run pressure lines to the bigger tank and then t- off from it to the smaller tanks to feed the the engines. I would be up for any suggestions on installing larger tanks for longer flight times.
Thanks
Doug
Old 12-06-2009, 10:17 PM
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Carlos Murphy
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Default RE: Twinstar Need bigger tanks

This is probably the #1 complaint about the Twinstar, I had my original "trainer" OS 40 FP engines on my first one and got 5 to 6 safe min flights.

With your 4-strokes you should get better times so I would recommend trying the stock tanks before experimenting with other tanks AND their placement.

Guy's have installed a tank in the fuse and used the wing tanks as hoppers.

After I got some time on the plane I would alternate "short" filling one tank and fly around until it ran out of fuel, these planes handle engine outs VERY well, after all they are twin trainers.

Do a search for "twin star tanks"
Old 12-08-2009, 03:27 PM
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ssmiff
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Default RE: Twinstar Need bigger tanks

Hope this picture answers your question, bought twin star as a twin trainer with OS25's but fount one very unreliable so went for SC 36's ie went with the added tanks which if I remember were 4oz
PS search this forum for other twinstars Very interesting;-)

Oops forgot to say work took over summer run out early flight times approx.8-9mins regards
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Old 12-08-2009, 08:54 PM
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aa1a
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Default RE: Twinstar Need bigger tanks

I put OS LA40s on my Twinstar. The flight time is short but tolerable. About 7 min. I had to move the battery back in the fuselage behind the wing and add some weight to the tail and to balance it. The two 4 strokes will be a little heavy and may make it hard to balance. It will also only clear a 10 inch prop between the nacelle and the fuselage so you will need a lot of pitch or 3 blades. But it will be a rocket!
Jim
Old 12-11-2009, 04:19 AM
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aerofly0610
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Default RE: Twinstar Need bigger tanks

Look at the TF DC-3 model and its placement of tanks. You could modify the wing to use the same setup.

http://www.top-flite.com/airplanes/topa0500.html
Old 12-23-2009, 06:39 PM
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Default RE: Twinstar Need bigger tanks

Hi, I am in the process of adding a 2oz. tank that is recessed into the wing between the throt. servo and the trailing edge of the wing. I got the info from another guy who was kind enought to pass it on. You will have too build or do a mod to the hatch to cover the tank but I feel its worth it. The fuel lines, Pressure from the muffler goes to the vent on the rear tank, fuel line(clunk) goes forward to the vent line on the front tank and the fuel pickup goes to the engine. I will post pictures as soon as I can of the mod. Hope this gives you another idea.
C.L. Baker
Old 12-23-2009, 08:10 PM
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Default RE: Twinstar Need bigger tanks

The Twinstar is a great little plane with two problems, small tank and the worst covered ARF on the market.
That said, I really like mine and enjoy each flight. I have safe 5 min. flights with my OS 32 f's, if I push it.

A little attention to re-design and I would guess a lot more would be sold. The boxy look could be much improved, with little effort, w/o changing the wing except to accept a larger tanks. I would pay more for a similar plane with those improvements.


Old 12-23-2009, 11:27 PM
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DougB1
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Default RE: Twinstar Need bigger tanks

Please post pictures when you get yours built. I am still thinking of putting a 8oz on the wing but would like to see yours before I do anything to mine.
Thanks
Doug
Old 01-29-2010, 07:26 PM
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oldtyme
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Default RE: Twinstar Need bigger tanks

I was able to get 6oz tanks in my Twinstar without alterations.
Old 01-30-2010, 11:26 AM
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JPMacG
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Default RE: Twinstar Need bigger tanks

I checked the capacity of the stock Twin Star tanks using a graduated cylinder. They are exactly 4 oz. This should be adequate for 10 minutes plus reserve using 25 sized engines, low nitro fuel, and some throttle management. If you put 40s on it, run 30% nitro and fly at full throttle most of the time then you will have very short flights.
Old 01-30-2010, 06:50 PM
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JPMacG
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Default RE: Twinstar Need bigger tanks

I'm assembling a Twin Star and I just noticed something related to flight time...

Using the tank, clunk and fuel tubing supplied with the kit, the clunk does not sit on the bottom of the tank! The fuel tubing is too short and too stiff to allow the clunk to fall to the bottom. If I assembled the tank per directions I would only be able to draw about half of the tank's fuel before it started sucking air. So I need either a heavier clunk or more flexible fuel tubing.

Has anyone else encountered this? What did you do?

Old 01-30-2010, 08:24 PM
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Carlos Murphy
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Default RE: Twinstar Need bigger tanks

Yes, true, just assemble the tanks as you would normally making mods as needed.
Old 01-30-2010, 08:36 PM
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JPMacG
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Default RE: Twinstar Need bigger tanks

Thanks Carlos. But what mods do you recommend? I could bend the metal tubing down so that the clunk hits bottom, but then I would have the same problem when flying inverted.
Old 01-30-2010, 09:18 PM
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JPMacG
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Default RE: Twinstar Need bigger tanks

Here is a photo showing the problem.
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Old 01-30-2010, 09:50 PM
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Carlos Murphy
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Default RE: Twinstar Need bigger tanks

You could bend the tube down a little but if you using the fuel line that came with the tank, replace it with a more flexible fuel line.

Old 01-31-2010, 12:21 AM
  #16  
JPMacG
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Default RE: Twinstar Need bigger tanks

Thanks Carlos. That worked. I bent the tube slightly downward as you said. I tried all the scraps of new tubing of various makes that I had and none was flexible enough. I found that old used tubing from another model worked. Apparently silicone tubing softens with age and exposure to fuel. Now the clunk falls to the bottom with the tank upright or inverted.

I suspect that others may be having this problem and don't know it. Some of the guys complaining about short flight times might actually be having clunk trouble in addition to the small tank.

My apologies to DougB1 for hijacking his thread. I should have started a new post.
Old 01-31-2010, 03:39 PM
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Default RE: Twinstar Need bigger tanks

oldtyme,
How did you fit 6 oz. tanks without modification??? Can you please provide the details so that I can also modify my Twinstar. I have 3 in the box that I bought from Tower last year at $109 before they raised the price to $129. I will do 1st twinstar in electric and the 2nd in .28 GMS glow engine. I already bought all the electrics paraphernalia with the fixed factory provided landing gear for a complete build and I also bought all the glow engine accessories with electric retracts for a complete build also. Before I start gluing things together on the glow Twinstar I would like to know how you converted to 6 oz. tanks without modifications to the nacelle or the wings. My other choice is to add twin 4 oz. tanks in the center of the wing as in the picture on post #2. I could drill out the necessary access holes for the center fuel tank fuel lines before I start gluing the wings together. BUT IF I COULD SEE how you did your 6 oz. tanks without modifications........then yours is the way to go. Thank you in advance for your valuable assistance.
larrysogla
Old 02-08-2010, 02:54 PM
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oldtyme
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Default RE: Twinstar Need bigger tanks

I replaced the tanks with Sullivan 6oz tanks.....but if you noticed that there was something wrong with the stock setups it would be obvious that you would replace or repair whatever was wrong.
Old 02-08-2010, 02:57 PM
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oldtyme
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Default RE: Twinstar Need bigger tanks

Larry,

It was a long time ago.....so I don't remember without taking the bird apart. I think I used either Sullivan or Dubro tanks but they fit......albeit snugly.......in the nacelles.

Andy
Old 02-09-2010, 10:22 PM
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JoeMamma
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Default RE: Twinstar Need bigger tanks


ORIGINAL: JPMacG

Thanks Carlos. That worked. I bent the tube slightly downward as you said. I tried all the scraps of new tubing of various makes that I had and none was flexible enough. I found that old used tubing from another model worked. Apparently silicone tubing softens with age and exposure to fuel. Now the clunk falls to the bottom with the tank upright or inverted.

I suspect that others may be having this problem and don't know it. Some of the guys complaining about short flight times might actually be having clunk trouble in addition to the small tank.

My apologies to DougB1 for hijacking his thread. I should have started a new post.
Bending the pickup tube downward will only hurt more. This is because the clunk will now stay towards the bottom of the tank. The first time your Twinstar is flown inverted it will suck air because the clunk will remain on the bottom of the tank.

I put my Twinstar together about 9-10 years ago and noticed the same tank clunk condition you described. I tried a softer fuel line, but it didn't last for more than a few months. Then I found an easy fix. Get yourself a couple of 1-1.5 oz. weights, drill 'em out and attach them near the clunk. It worked great for me !

Joe M.
Old 02-09-2010, 11:04 PM
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larrysogla
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Default RE: Twinstar Need bigger tanks

oldtyme,
Thanks for your valuable reply. Are you still flying your Twinstar. I have not built/finished any of the three $109 Twinstars I bought at Tower Hobbies more than 1.5 years ago. I bought all the complete radios(Airtronics 2.4 RDS 8000), electric retracts, wheels(aluminum hub/rubber air), brushless motors, ESC, Glow GMS .28 glow engines and all the Radio South hinges, pinned hinges from Tower Hobbies..........etc. I bought a whole bunch of electric paraphernalia, aluminum hubs/rubber air tires from Hobby City/Hobby King as they have very good prices. When I start building my electric Twinstar and my glow Twinstar.......what tips, suggestions do you have to avoid pitfalls in the build up??? Thanks for your valuable reply.
larrysogla
Old 02-11-2010, 03:42 PM
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BobieC
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Default RE: Twinstar Need bigger tanks

Hi

I have had a twinstar for a few years and i use it for running in engines and setting up pairs of engines for other aircraft i must agree that tanks are to small i have fitted up to .40 size 2 stroke's and at full power the landing time comes round very quickly

so i fitted a 14oz tank into the fusalage and changred the plumbing round a bit , I took the 'Carb' line out from the 14oz tank to a tee and then into the 'presure' line of the small tanks in the wings i then took the 'carb' line from these tanks to the engines

i then took a pressure line from each silencer to the 14oz tank in the fusealage

This gives me about 12mins with 40's and i land after 16-17 mins flying with fuel still in tanks with 25-36 size 2 stroke's and a bigsmile on my face

2 down sides are 1. refeulling you need to fill form both'carb' linesuntill fuel flows from both 'pressure' lines
2. a gal of fuel is used up quickly

but the plane flies fine


Old 02-12-2010, 08:56 AM
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Default RE: Twinstar Need bigger tanks

Hi!
Why don't you guys just replace the stock 4oz tank with Tettra "Bubbless" tanks??
They are the best tanks possible, long and slender and no clunk to worry about!
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Old 02-12-2010, 12:30 PM
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JPMacG
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Default RE: Twinstar Need bigger tanks

Will the Tetra tank fit in the Twin Star's tank compatment?
Old 02-12-2010, 02:59 PM
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BobieC
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Default RE: Twinstar Need bigger tanks

Hi

I am not aware of these tanks or if they fit the supplied tank is approx 45mm X 45mm X 65 and the tank bay is approx 50mm X 55mm X 75mm

the thrid tank was a easy answer as like most modellers we have spare tanks in boxes under our benches

one other good point is that when you are starting up if one engine is slow to start the thrid fills both tanks back up soboth engines run out of fuel at the same time ,i have once forgot the timer so i had 1 engine cut and then theothera second later

i also found a Tristar picture on the web


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