Flowmeter?

[jasoncsc]

Can anyone tell me what is a flowmeter and its application? Is it "really" useful? Thanks!

 

[Kez]

A flowmeter is a device that measures rate of fluid flow (gases and liquid). I believe you are refering to the use of a flowmeter to help set the needle valve. I have tried that before but it will be just as easy setting it the traditional way. ie start off on the rich side and then lean 1/8 turn and send the boat out; and repeat.

Kez

 

[Mike Hughes]

The flowmeter will not make your boat run perfect. What it will do is set the carb to the same flow as it was when you had the boat haulin *ss. You must get your boat running perfect, then you can flow the carb. Next time out, your set your carb to this reading and the boat will run like it did earlier. You usually start the day off with cold air in the morning. As the day progresses, your boat will go leaner as the air warms. If the needle is set right on the edge your boat will go lean and die later in the day. You can adjust for this with the flowmeter. If you change anything on your boat (prop height and angle, prop and or pitch, weight, different glow plug, % of nitro), you will not be able to use the same reading. You must start over. Since I went to 3rd channel needle, I don't use the flow meter anymore to tune for the race. I use it to get rough setups for the 3rd channel needles and carb diagnostics.

Mike

 

[TimD]

I second Mike's comments to the letter!

I mainly use my flowmeter when I'm testing or working on the 3rd channel setup. Rarely use it at a race meeting. A good companion to a flow meter is a thermometer and a pen and a book for readings etc.. If you really want to spend money you could get a RAD (relative Air density ) guage too....

How serious do you want to go? $$$racing!

 

[Ian Inverarity]

I have seen people put way too much faith in their flow-meters to tune their engines. For example an engine with a leaky pressure hose will run lean at the same flow meter setting! I would say they are a useful device, but personally I dont use them and tune my motors by ear. I have to say the 3rd channel method is probably better and will be going to that soon. For myself I cant justify the cost of a flowmeter.

Nitrocrazed racing: Leaner...leaner.. leaner... Ops, not that lean!

 

[Mike Hughes]

That is true. At least this way you will know that it is not the carb setting. Testing a lot of boats the day of a race for a needle is a lot of work. This is the main reason I went with the flowmeter. It is a lot cheaper to go the way of the flowmeter if you have a lot of boats. Going to the 3rd needle is the best of all. A lot more exspensive then the flowmeter with servo, needle, and 3 channel radio multiplied by everyone of your boats. I personally run 6 boat at ditrict level and 14 or so at national level. Lots of $$$. Sometimes I don't even care if I get to test my boat. I usually fire it before the heat and tune during the mill. Usually not that much off unless I change something.

Mike

 

[Ian Inverarity]

14 boats! Wow! I dont think I could stand that much fun/frustration! 2 or 3 is my limit!

I am not saying a flowmeter is not a useful device, but just that I have seen people who launch their boat sounding lean to me, but they are sure it is okay because the flow meter said so! Needless to say it stops because it is lean.

The A motors I use have radio needles supplied, and my radio is already 3 channel, but I agree if all this needs to be purchased then it is probably more than a flowmeter.

Nitrocrazed racing: Bring on EFI....

 

[TimD]

Ian,

Should I bring the flowmeter over @ the Nats so you can have a play ;D ;D ;D

Smuggling the gas bottle onto the plane could be tricky

TimD racing: Permission granted to go to the nationals 1400 Kilometers away!

 

[Ian Inverarity]

Yep, bring it, I will play with some carbs! ;D

I have a 4kg gas bottle for the BBQ, so you dont need to bring yours!

Ian.

 

[TimD]

Different fittings :-

Plus we might need the BBQ!

Side note: I used my BBQ burner to heat the teflon couplers up last week! No torch yet 8) That stuff stinks :-X

 

[Ian Inverarity]

Can you get an adaptor? That is a big gas bottle, I dont think they will let you on with it. Although I do know a bloke who flies with his... 8)

I use the gas stove top for heating engines to replace bearings, annealing brass stuffing tubes and fuel lines etc, but messing with teflon indoors is a no-no. PTFE (Teflon) is simply carbon and flourine, and flourine is very nasty stuff....

Nitrocrazed racing: I remmember chemistry from high school.

 

[TimD]

It uses a "primus" fitting.....

Don't know about the adaptor.

I just bought a smaller - more portable 1.25kg bottle for it!

 

[Ian Inverarity]

Might pay to ship the bottle over seperatley, or give it to someone who is driving over. 8)

Dont want to ruin Qantas' perfect record....

Nitrocrazed racing: I just say they are model boats. I never mention they are engine powered race boats....

 

[TimD]

Hey Grub,

You are driving over aren't you? Got some spare room in the trailer for a gas bottle and a starter box? I'll shout you a few Pale Ale's as courier fee's ;D

 

[Zimmerman]

Flow meters have a place in one's arsenal. If used properly it can even indicate if bearings are going south. Sorry Mike, but if you have everyone believing how the needle changes as the air warms, etc. then you have no business messing with flow meters.

 

[TimD]

I believe it depends on what type of flowmeter you have......

Some compensate for atmospheric changes - other's don't.

 

[rcboatlover]

I have seen used flow meaters for sale in the past, and they arn't cheap, but to me they look really easy to build. I think the hard part would be finding the correct gauge to buy.

Does any one have plans to build one? I would be really interested in learning more about them.

Thanks for the help! Dale P.

 

[ClayGlover]

Flow meters have a place in one's arsenal. If used properly it can even indicate if bearings are going south. Sorry Mike, but if you have everyone believing how the needle changes as the air warms, etc. then you have no business messing with flow meters.

ok Zimm, now i'm confused :- i thought the purpose of using a flowmeter was to have a repeatable optimal air/fuel mixture setting that is compensated for air density changes due to weather. as we know, temp affects air density. help us out with some more details...

 

[Rick Kelley]

I believe what Zimmerman was trying to say was... That as the air temperature raises, the air becomes less dense. This would tend to richen your mixture not cause it to go lean.

Rick

 

[ClayGlover]

ah, yeah. mike knows it goes rich, he wasn't thinking right while typing the post

lol