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Nalgene bottle air trap question

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Nalgene bottle air trap question

Old 02-13-2020, 07:30 AM
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cbk07
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Default Nalgene bottle air trap question

Quick question....I assume on a Nalgene bottle air trap (ie MAP, etc) that either of the top nipples can be used for fill or feed from tank? Seems like It shouldn’t matter, but want to verify. Thanks!

Old 02-13-2020, 08:21 AM
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Canadian Man
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On that one yes. Either can be used.
On the high flow ones there will be one big and one small nipple. Small is for fill.
Old 02-13-2020, 08:28 AM
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cbk07
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Thank you for the quick reply

Also while on that subject, is there a need for high flow on a 140? When is it actually necessary or beneficial?

Last edited by cbk07; 02-13-2020 at 08:31 AM.
Old 02-13-2020, 09:04 AM
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140 you're just fine. I've seen individuals make comments that 160 is their threshold, according to BVM's page about high flow systems 180 is their suggestion, but you shouldn't see any issues with a 140 for sure.
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Old 02-13-2020, 09:11 AM
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CARS II
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I'm running a 140 and I got an air trap like the one on your picture, not a single problem in about 3 hrs of use, we learned some time ago that if you go above 140 then a bigger/diferent air trap should be use.

Tygon fuel line can be use on the fill side, I also wrap a turn of the white Teflon tape around the neck to aid the cap to seal since the bottles expand and contract when been fuel or de-fuel.

Last edited by CARS II; 02-13-2020 at 09:19 AM.
Old 02-13-2020, 09:16 AM
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My rule is if it’s a Rxi ( internal pump ) then Hi-Flow from 90N. Outside pump then 160N.
We are running P-300 Pro JetCats at 308N with a 4oz MAP twin inlet Hi flow and it works great

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Old 02-13-2020, 10:23 AM
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The Hi flow has a smaller fitting for the the fill line. Standard like that’s both are the same.
Old 02-13-2020, 10:51 AM
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To be 100% clear, the High Flow has bigger feed fittings (from and to) the fill is the same size fitting as the standard size.

Old 02-13-2020, 10:54 AM
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cbk07
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All good info. Thank you again guys
Old 02-13-2020, 12:08 PM
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Now John has introduced the new replaceable larger filter they are another step above everything else. The surface area of the pleated pick up was already 30% higher than the plain cylindrical type, the new ones are double the area-and they unscrew for replacement.


Old 02-13-2020, 03:17 PM
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A fuel system is only as big as it's smallest component. Don't forget your vent(s) and other (e.g. tank fittings.) Also, the fuel line size also matters. If the fuel pump is in the turbine, then everything needs to go up in size. As Dave suggests, 90 size is a good breaking point for a turbine with its pump in the turbine. My Ultra Flash's P-140 had a problem with a small UAT even with larger vent(s) and lines. It has a main tank and the saddle tanks.

The size of all fittings and UAT, etc. is also dependent on what your tank arrangement is. On my P-140 RXI, the turbine was not able to get enough fuel flow through the main tanks and two saddle tanks. After changing to a High-Flow UAT, it still had a problem because every fitting in the system, including the vents, tank fittings, etc.had to be high flow too. Of course bigger fittings = bigger fuel line size too. Once everything was set with high flow components, then the P-140 RXI worked correctly. Oh, I also ended up with a high flow vent on each of the saddle tanks and they were in parallel versus series.

The above being said, my K-160 with an external fuel pump, works just fine on a 4mm line between the pump and turbine. But all the fittings and lines are high flow on the inlet side of the pump. I use the smoke tank for extra fuel and the system works fine drawing through the two tanks.
Old 02-14-2020, 04:18 AM
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David appreciate your love of the MAP but seriously that filter was used extensively in my original CAT products going back 10 years, as I said back then they are the best for this application period - 'step above everything else' mmm you should be in advertising and PR!

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Old 02-14-2020, 04:46 AM
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I still use them exclusively. They are simple, small and work even when mounted at various angles. KISS. And, … they are a lot cheaper and more available than some of the other stuff out there! Lastly, when you have questions, John answers his email and phone calls! What more can you ask for?
Old 02-14-2020, 10:59 AM
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MAP bubble traps have been around way longer than 10 years.

What else is selling other than advertising and PR!
Old 02-20-2020, 06:40 PM
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Originally Posted by Len Todd View Post
A fuel system is only as big as it's smallest component. Don't forget your vent(s) and other (e.g. tank fittings.) Also, the fuel line size also matters. If the fuel pump is in the turbine, then everything needs to go up in size. As Dave suggests, 90 size is a good breaking point for a turbine with its pump in the turbine. My Ultra Flash's P-140 had a problem with a small UAT even with larger vent(s) and lines. It has a main tank and the saddle tanks.

The size of all fittings and UAT, etc. is also dependent on what your tank arrangement is. On my P-140 RXI, the turbine was not able to get enough fuel flow through the main tanks and two saddle tanks. After changing to a High-Flow UAT, it still had a problem because every fitting in the system, including the vents, tank fittings, etc.had to be high flow too. Of course bigger fittings = bigger fuel line size too. Once everything was set with high flow components, then the P-140 RXI worked correctly. Oh, I also ended up with a high flow vent on each of the saddle tanks and they were in parallel versus series.

The above being said, my K-160 with an external fuel pump, works just fine on a 4mm line between the pump and turbine. But all the fittings and lines are high flow on the inlet side of the pump. I use the smoke tank for extra fuel and the system works fine drawing through the two tanks.
What do you mean by vents?
I suspect that drawing 1 litre of air per minute through a 4mm festo line shouldn't be a problem.
But the suction lines containing fuel are critical. So main tanks/uat/filter/pump: the flow demands increase in that order.
Old 02-20-2020, 08:58 PM
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sysiek
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But remember the most important thing is to have the big vent lines to the fuel tanks or your uat tank will start to collapse and have fuel restrictions.
Old 02-21-2020, 05:19 AM
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Regarding vents: For example, in the Ultra Flash I have a main and two saddle tanks. The two saddle tanks are in parallel to each other and in series with the main tank. I could not get them to work with them all in series w/o causing the UAT to collapse, even with high flow fuel system components. Each saddle tank has its own vent line which terminates outside the bottom of the fuse. There are fittings in the bottom of the fuse that the vent lines attach to. The holes through the fittings can be constraints if the holes are not large enough. Also, some folks add some filters on the vent line. These filters are another potential constraint. Sysiek is right. If you see your UAT collapsing when at full power, your fuel system is constrained.

Regarding vent line filters: I personally do not use filters. But, I do flush the vent lines into a taxi-tank every time I fill it. That is why it may not be a good idea to reuse fuel that makes it to the taxi tank, especially if your frequently flying off grass or dirt. If I was flying off grass or dirt, I would use a separate taxi tank for filling/flushing. But I have a nice asphalt 3800' runway, pit row, ramps and concrete fuel pads here. Only time I got off pavement was at Joe Nall and that made a mess of the gear and bottom of the plane (i.e. grass clippings and dirt all over the gear, flaps, hinge lines, etc.) It think it was Bob V. that once told me, "Never fly off wet grass. Better to wait till it dries." Good advice!

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