Lynx MOAS clunk - Not impressed...

[HeliBenj]

Hi guys,

I'm not sure this is the right place to discuss that topic but I have found no better. I haven't seen much discussion about this product so here's my experience.

I got a MOAS clunk for my Srimok as I didn't want to mess with the potential flame outs of a clogged filter because of a possibly separating fuel magnet. I have been running OS Bubbleless on my nitros before with great succes I must say.

I didn't like the MOAS because:
- Way to light, which requires a really thin clunk line to get it to move around any.
- When pumping fuel out of the tank through it, it sucks a lot of bubbles towards the end of the tank. Now this could well be different when engine is sucking fuel in operation because its demand is less, I don't know
- I had an almost flame out with it with half an inch fuel left doing just flips. That leads me to think it doesn't follow the fuel very well (light) AND doesn't retain much fuel at all in the sponge.

OS clunk is back in the heli with no flameouts until 99% dry...

[Y@nkee]

Hmm i was planning on using the lynx moas in my srimok, but now you might have put me off that plan, others thinks that the moas is better than the fuel magnet, just beacause of what you said about the fuel magnet disintegrating and clogging the filter.

Anyways i might go for the fuel magnet after all, i am going to use a hz-r and wont get the exhaust fumes in the tank.

Off topic:
Does this mean you have got to test your converted srimok now?

[HeliBenj]

Hi Jan, this is only my opinion, I hope more people will chime in on the subject.
In your case I would definitely go for the fuel magnet, as I understand it there is no risk of foam degradation with a crank pressure system as long as you leave some fuel in the tank at all times.

Yes I got my Converted ECO to fly but I'm not happy with the vBar yet, I need some more tweaking, only a question of time (which I lack) and then I'll report back on the conversion thread

[Raptor30_V1]

Hello,

I think, the goal of all this approaches is, to have a continous and steady fuel flow. There are IMO 3 approaches:

1.) the header tank
2.) fuel magnets and comparables
3.) uniflow systems

Funningly, before making the Yamada-experience, I flew OS-engines and the header tank worked well for inverted flight (I used to fly almost the whole tank inverted). But yes, it's noticeable, that the header still does not prevent engine from running leaner when fuel-tank level gets lower.

I never tried the fuel-magnets, as capilar forces can't keep that much fuel neither (else that would be a pretty large clunk?) .. and I completely dislike the idea of having some textile/ sponge material on a clunk as parts can separate and remain in the tank?

So, coming back to the goal, to have a constant fuel pressure to the carb, the only real simple but effective solution is a uniflow system. I never tried it myself, as my Yamada's with header tank run w/o any problems, but the uniflow-system is the only one, that obviously would solve our concerns ..

Don't know why (well, as usual, rc-idustries serves other goals than our daily problems and desires) - but the uniflow system never got realized by any manufacturer. This would be pretty simple, to have 2 clunks (at always same pressure level) delivering a pretty stable fuel pressure over the whole tank level?

So a header tank and a fuel-magnet help to keep fuel for a little longer - and, addiionally the header helps to keep the pressure drop (perte de charge) less variable over the tank volume - but not the ideal state of having constant fuel supply?

I always wondered, why some people bother about fuel supply and on the other hand use pretty small fuel-tube (inner diameter) and e.g. in-line filters adding lots to the pressure drop till the carb?

So, considering industries doesn't deliver uniflow-systems () .. what can we do?

- use a header tank to get a smoother pressure drop over the run-time and/ or to get longer flight time ..

- reduce unnecessary additional pressure drope by small inner-diameter tubing (I use 2.5mm and not 2mm inner-diameter) and lots of complicated filters etc. (20 years ago a filter inbetween tank and carb was a no-go - we focused on any detail not to get some dirt in the system)

- if having a Yamada, seal the whole tubing etc. against pressure lost (300 mbar?)

Different taste, different oppinions ,
Best Regards,

Oliver

P.S: Considering no uniflow system available (and even then) .. the Yamada-system w/o rotary/ friction parts is the best system to have more or less steady conditions ..



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[ininverno]

Dear
I am Luca Invernizzi, Project Manager of Lynx Heli Innovations.
About MOAS, I really need understand why one user is not happy, when more of 10K are..mmm??.
Can you please tell me exactly what you don't like?

[HeliBenj]

Hi Luca, thanks for chiming in, it's nice to have the manufacturer around here.

Maybe I'm a black sheep in 10K, this I don't know, I'm just telling my experience. Maybe i'm not using it correctly either. Understand I don't mean to bash on the product, just wanting to share here and maybe making it better in the future?
What I dislike is in the first post. As stated I had a near flame out on some flips. I believe my clunk line is set up correctly. Maybe a bit more weight in the clunk would solve the issue?

Also what is your 10K satisfied customers based on? Sales? Just curious

[helihot]

Hi, i'm Edouard Dechen from SC Distribution the French Lynx distributor,
In first we base the "10K happy customers" on the sales feedbacks during events, pilots, visits at shops, emails, discussions, sales... we don't do any publicity about MOAS the last year, pilots buy it cause they heard about the product efficiency.
About the MOAS, Lynx sale a lot of MOAS through the world and the pilots who had the same problems like you they changed the fuel tubing for LX0134 and keep a 5mm space between the MOAS and the bottom fuel thank.
Now, you've the right to don't like the product but it have to work well into any fuel tank. So please let me help you, contact me by the SC Distribution website and i will to send you a piece of slim fuel line tubing.

Best regards,
Edouard

[ininverno]

Dear, I will explain soem more about MOAS, maybe we can find the reason why in your set up don't worl perfectly.

MOAS was design with that weight because must be floating and not negative in the tanks, this will speed up the move responce of the moas to be were the fuel is quick as possible. (if was heavy he will be in one side, than when you flip the heli he will take more tiem to move were the fuel is).

Witch kind of fuel line you use with MOAS? we advise the thinner and flexible fuel line possible. In the end to made the best result we design our OEM fuel line , super thinner, super flexible advised for tank and MOAS. Soem user find the normal fuel line hard for the MOAS in winter time with colder temperature, than why we made Lynx one.

Many test was made using the lynx fuel line (the smaller one) and MOAS performance was increased.

One other advise (maybe not necessary for you) is that using not pressurized engine system, needle setting must open a bit compared the std clunk.
User with YS and new OS Cline report us no change or very smaller change.

The good side of MOAS is that once you use it, you don't need carry about him as other system, also the fact is light will not destroy the fuel tubing increasing the fuel line life.

Really hope my reply can help you and other to get the best form MOAS.

[HeliBenj]

First off, thanks both for the quick replies and great support. This speaks very well of your company

I'm using a thin clunk line I bought at fast lad (http://www.fast-lad.co.uk/store/thin...92-p-4552.html), quite flexible stuff (enough for the other clunks I have used until now).
Maybe MOAS needs even more flexibility. In fact the tank hole on my Srimok is located above center, and I can see the MOAS barely bends the line enough to get to the bottom, so that might be the reason. Maybe the shape of the tank causes that (it's higher than wide). I can see on say a trex 600 that could be different (longer clunk line and not very high tank).
I would be happy to try the Lynx line.
I saw in another thread people was wondering if the line is big enough to feed a 90 (OS 91HZ in my case). Any thought on that?

Lastly, if this cures the problem and if in some cases the use of This specific line is necesary for good performance, that would be worth putting some kind of advice when you go buy a MOAS in my opinion.

[ininverno]

Dear
I thinks we define the reason why...
Yes I check the fuel line you use now, this is too hard for any king of NOT standard clunk.
Lynx made this; http://lynxheli.com/product_info.php?products_id=82

I give you right about give more info about advises fuel line. i will update now the web site information.

about your or other user worry about 91 or fuel feeding, we made several bank test during design, one was (using special carburetor vacuum tester) check the max fuel draw and we terminate how many ml/sec 91 engine need max 1.11 ml/sec in the YS,
Than we test the necessary flow load to get double ml/sec (2 ml/sec) and MOAS was designed to get better flow load according this test.

Please contact your country distributor. edouard will be happy to send you soem samples of our lx0134 to test.

Any future need or assistance about our product please contact me at service@lynxheli.com
Friendly Luca Invernizzi

[nwmtech]

I can confirm the exact same issue. The second the moas touches air it starts pulling bubbles. Took me a couple tanks to figure out why I was running lean at the end of the tank. Pulled the moas and replaced with a fuel magnet again and all went back to normal. This was with Hayes clunk line which is very soft and pliable.

[johnpotter82]

I will be anxious to hear the flight test on the mods helibenj. I am looking at this system with the os- hz-r

[cadkins]

I just installed a MOAS in my new Trex 600LE. I also bought the Lynx clunk line but I did not use it as the ID was only 2mm. I installed it with the Align stock clunk line for the time being. I am also concerned with the weight of the MOAS. The Trex 600 tank has the nipple on the right side which could cause an issue with fuel supply in a sharp left turn with a light clunk.

So Lynx is recommending the MOAS with the 2mm ID clunk line? One of your reps on HF said he burned up a motor using that line and a MOAS.

I have read some positive reviews on the MOAS but they did not mention what fuel line they were using.

Chris

[nwmtech]

While a softer clunk line will be better it's sort of a moot point if the second part of the clunk hits the air you start seeing bubbles in the fuel. It's an easy test. Fill your tank 1/4 full with a hand pump then slowly start pumping the fuel back out. For me, right when the top corner of the MOAS hit the air I started seeing bubbles and it got worse the farther down the fuel went. This was with between a 1/4" and 1/2" of fuel left in the tank. I did this test AFTER experiencing the motor running lean with about that same amount of fuel left in the tank. I performed the same exact test with a fuel magnet and had zero bubbles until the bottom of the tank was sucked dry.

Simple test. Obvious results. I would encourage everyone else to try this and post if you had results that differ. Maybe I got a bum one?

[ininverno]

I thinks you made the wrong test for sure.
Test need be done in the air, during the fly, making 3d not in the static position.
Moas was designed to move into the tank more possible and capture fuel and feed engine.

Also if you like do test in static position you need respect the flow request of the engine , that is 1.11 ml/sec, if you drop more of 2ml/sec for sure you will made cavity and air will pass, is pretty normal.

Spongy you like for sure will absorb more fuel in static position, but will destroy very quickly , were Moas stay forever.

Reason we design Moas was first to stop the continuous replacement of the spongy.
If you are happy with spongy, please use that. But if you are tired to chage the spongy all the time than maybe Moas is the solution.


About 2mm fuel line we design, is recommended inside the tank, between nipple to the Moas, not for outside.
For outside tank we just released a new bigger diameter, but this is one different situation.
Material was defined to have longer spam life, we don't buy from some producer, we made our recepie to resit chimistry environmental inside the tank and we made our tubing. Lynx Team we are all competitor flyer, and everything we sale was tested for month before release, we don't like sale thinks just for sale...

Hope I explain the situation.
Try it in fly, not at home.
TTYL

[Eigil]

I have been using the MOAS in my Srimok since the MOAS came to marked. I used the Fuelmagnets for years in different models before I changed to MOAS. I am really happy with the performance of the MOAS.

I had to richen the needles just a little (a few clicks) and has never had any problems with leaning out during the flight. I do see bubbles in the fuel line when I pump the fuel out of the tank, but has no issues when I fly.
I have not yet tried the Lynx fuel line, I am using the Hayes at the moment. But I will try the Lynx fuel line shortly.

So for me at least the MOAS has the same performance as Fuelmagnet in the air, and do not break apart and clog up the filters after a period of time. My MOASes are still like new after 6 months use.

[Daniel Jetschin]

Hi

I am running the MOAS since last July, on my OS 91 HZ-R with only the best results and constant mixture for the whole duration of a tank. I'd like to share some experience on non pressurized systems, but I can only speak for pressure systems wich the HZ-R features.

Daniel

[cadkins]

Daniel,

What clunk line are you using?

[Foxden]

I'm also running the MOAS in both our Vel 50 and Vel 90 machines, I'm running Hirobo clunk line, very similar to the Lynx clunk line in that it is small and thin and very flexible, allows the MOAS to move around the tank with no problem, the stock clunk line that is included in the Outrage Vel 50 and Vel 90 kits also works well, there is a small piece of thin tubing along with the line used for interconnecting outside the tank.

[DanCopter]

I just switched to a MOAS for a trial. I've been using a Fuel Magnet for just over 12 months. When the YS SRS came out I could never really get it to run without bubbles in the fuel line so I thought I would give MOAS a try.
For me it was an instant fix, no more bubbles! I'm no pro but can throw the aircraft around a bit on it's back and upright, running right down to an 1/8 inch (to test it for flame out, I only run down to 1/2-1 inch normally) with no problems at all, am very pleased.

The fuel tubing is standard clear tubing, not the thin walled stuff or the align tubing. I don't know what the ID is but it's not the wide ID stuff.
The MOAS doesn't sink when the tank is full, just floats in the middle and near the top of the fuel as it burns down.

I was concerned about the filament being fibre based and bits getting up into the filter but so far that hasn't occured.
Next thing is to see how long it will last. I keep the heli stored with fuel- a habit from the fuel magnet but they say the MOAS can be stored dry.

Hope you get the problem sorted out.