Main tank clunk line problems.

[Ah Clem]

"I think you have the right idea, but too concerned about it reaching everywhere. Don't worry that it can't reach all the corners. Not all tanks are symmetrical. It's more important that it move freely than each the extremes. Just get close. Same for the header tank. You should be fine."

Again, very wise Rob!

Great advice!

[aseejr]

I too had a problem with my clunk line that led to a burnt Redline TT53 motor (I think it was my fault though). Couldn't get a hold of Hayes line fast enough.....now using Align fuel line (with no issues). At first I thought of using the high quality JR line as it is really flexible but found that Align line has thinner walls....a little more flexible than the JR line.

[Vaeloron]

I learned a cool trick today to clamp fuel line. I inserted a pair of needle nose pliers into the tubing and stretched them open and slid a section over the nipple. I was actually able to use one size SMALLER than the size that was there and its clamped on real well now.

[Nitron]

The fuel pickup line does not have to reach all four corners. When the heli is sideways, it's weightless and so is the fuel and clunk in the tank. If your pulling a turn, the G force keeps the fuel and clunk together.

Try sullivan medium fuel line. I use it in my fuel tank and it lasts a reasonably long time. It's a white/clearish color and is very much softer than say, Dubro fuel line.

Curtis

[Vaeloron]

Originally Posted by Nitron

The fuel pickup line does not have to reach all four corners. When the heli is sideways, it's weightless and so is the fuel and clunk in the tank. If your pulling a turn, the G force keeps the fuel and clunk together.

Try sullivan medium fuel line. I use it in my fuel tank and it lasts a reasonably long time. It's a white/clearish color and is very much softer than say, Dubro fuel line.

Curtis

Thank you for that. I never considered what G-forces do to the fuel. This makes me feel better. I have switched to a Lynx M.O.A.S. pickup and ditched the header tank. It flew great today.

[skytrekin]

I would be weary of using to small of fuel line for fuel flow reasons. Smaller line will not flow as much as regular line. However it would seem to be pretty flexible.

If you are worried about the fuel line coming off, I have seen people use the same size line fit over itself on the nipple.

Example: take a piece of fuel tubing and cut a small section off kinda like a big O ring and fit that over the existing line on the nipple.

But in reality I have used a YS 91 for years and never had any fuel or pressure lines pop off with simply pushing the line on the nipple. Now if you fill the tank and don't vent the tank, the line will surely pop off. But that is a lot of pressure.

Some people complicate things way to much in my experiences.

[joecass2]

Originally Posted by Vaeloron

Thank you for that. I never considered what G-forces do to the fuel. This makes me feel better. I have switched to a Lynx M.O.A.S. pickup and ditched the header tank. It flew great today.

I tried using a Lynx M.O.A.S. but this made my line even shorter witch made it hang in the middle of the tank. what clunk line are you using? I also would still use the header tank. with the Lynx M.O.A.S. in the main tank the header tank will not get much air in it.

[Vaeloron]

I am using Hayes. There are a few things to take into consideration with the M.O.A.S. first of all its weight changes when it is saturated. Also remember a fuel magnet is designed to hold a short supply of fuel trapped in the element so even if the pickup is briefly out of the fuel it will not start drawing air instantly. Don't listen to the people that tested it with a fuel pump and it drew air. Pumps draw fuel much faster than an engine. As was mentioned here previously you need to take g-forces into consideration as they will pull the pickup down into the fuel. I decided to remove the header tank because it is not normally needed with a fuel magnet and it's one less part to fail. I have a few flights on it now and they have been great.

[Full Montee]

Another thing I found with my x50F was the boom clamp was slipping on the boom under force. Another x50 owner brought this to my attention. Besides flying better once I corrected the slipping issue the x50 also stopped the header tank from filling up with so much air.

[Rob43]

What did you do to correct the boom slipping? Tape under the clamp?

[Ah Clem]

"What did you do to correct the boom slipping? Tape under the clamp?"

Rob,

I cannot speak for the X50, specifically, but I had the same issue with the Raptor 50.

I put a wrap or two of tape around the boom, and it has not moved (in over five years), so that is a viable fix.

If it has a torque tube, I would just pin it with a screw as with Align, Outrage, or AleeS. That works great too!

[Full Montee]

Pinning would definitely work and be way better, as a quick fix I used tape at a fun fly.
It fixed not only the header tank empting faster but also improved tail authority in tic-tocs.

[skytrekin]

Pinning the boom on the X50 is not necessary. It comes stock with 2 screws on each side of the forward support that act as "pins" and a large pin in the tail case that prevent the boom from coming out under any piro action you feel you can dish out.

I just have passed the 3 gallon mark on my new X50 and the stock boom clamp has not slipped once since I have tightened it since the build.
A difference I have done departing the build manual is to locate the lower boom supports down to the landing gear and swapping bolts from the frame spacer just behind the tank.

My main tank clunk "the pointy one" with regular fuel tubing and header tank have worked flawlessly. Everybody has their own way of doing things. Never one lean run and perfect fuel draw every time.
Keep it simple and just fly.

[Full Montee]

Sky I believe we may be misunderstanding one another.
While at a fun fly this past September I met up with another x50 owner. His boom where the aluminum support clamps the boom was leaving wear marks on the carbon fiber boom. The wear marks were in the direction towards the front and tail of the heli.
This could be seen if you would grab the boom block and tail case and push down or pull up on the tail case while keeping the boom block steady.
Wrapping the boom with tape where the support clamps the boom solved the issue for me.
This was not seen as side to side flex which I would expect from pirouette maneuvers.
Taping the boom for me stopped the header tank from being slightly emptied before the main tank and also stopped my tail from drifting while doing elevator tic-tocs.

[Rob43]

Cool, buds. I had already taped the boom in the area of the clamp to protect the carbon from being damaged. Last night, I was looking it over and noted my clamp isn't metal-to-metal when I had tightened it, so it's not bottomed out, so to speak. I think it should be fine.

Thank you for the clarification.

[Vaeloron]

I am really happy with the M.O.A.S. I finally have the engine dialed in and flying great. I am sold on the fuel magnet in place of a header tank. It makes more sense. When you get air in the header tank its there for the rest of the flight but if you get air into the fuel magnet it comes out once the magnet touches the fuel again.

[joecass2]

i got some of the lynx clunk line it's only 2mm ID. is this going to be a big restriction? most clunk line is 3mm ID. im using a YS 60 engine. let me know if you guys think this is going to be ok.

[Rob43]

It cannot cause restriction when used as described. The short piece (between 1/8" and 1/4" long) will only fit over the line where it's attached to the barbed fitting. Therefore it will not having anything to do with restriction. It can't make the line smaller than the fitting. I have this installed on all my attachments as well. I used a zip tie on each end of my clunk lines (done this before with no problems), but may replace them with a piece of regular fuel tubing as well.

Be aware that Hayes will swell in the heli fuel, increasing in length. So, cut it to excess length, pre-swell it in fuel for a couple of days, and then cut it to precise final length for the clunk installation, and install it. (Crap - I will have to pre-swell another length of Hayes to do this...)

[Vaeloron]

I think he is planning to use it as the main clunk line. Not just to clamp the line thats there.

[Ah Clem]

I use silicon for the clamp line, as it is less likely to split than the Hayes, when stretched.