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prkaye

Well Known Member
How important is a fuel flow sensor for an airplane with a Carbeurated engine and a FP prop? I've never used one while flying.
 
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The "aircraft" does not need fuel flow information...

...but as a pilot, it does provide useful information, and is another way to optimize the fuel consumption of the engine knowing MP /altitude / temperature, etc. This requires you to know and remember all of the performance parameters, charts, and operating conditions of your engine, or are able to look them up in the engine operating manual.

You can take a lot of pilot memory work out of the equation (assuming you want the information and want to fine tune the engine operation) with a fuel flow sensor that inputs its data to a fuel computer that will now show gal/ hour consumption, total gal used, gal remaining...and, if provided to your (if installed and enabled) GPS, a go/ no go for your flight plan based on fuel requirements, or issue a warning if your fuel remaining will not get you to your intended destination.

A clock / stopwatch can indicate flight time, and therefor you can calculate fuel consumption, so overall fuel flow information is also available "the old fashioned way".

Only you can decide if fuel flow information is desirable.
 
In my Cheorkee 180, I found it extremely helpful. It was more accurate than the original Piper guages. Also, with the added benefit of coupling it wih a 430/530 it provided a fuel remaning at destination estimate. Like noelf stated, it takes a lot of guess work and other calculations off your workload. I wouldn't be without one.

bob
 
One of the best instruments I ever installed. Didn't have one for the first six months. No more guesses or approximations. I know within just a few tenths of a gallon of how much is used, how much is left, how much is required to get to the destination, and being able to fine tune for fuel efficiency if desired.

L.Adamson --- RV6A
 
The advantages are many - lots of threads and postings about why. Here is one that is an example:

http://www.vansairforce.com/community/showthread.php?t=12968

Pete has really set the standard for running at peak performance (in this case best engine management for a carburetor) by knowing egt and fuel flows.

One can really learn a lot about the engine's operation through knowing fuel flow. And, of course, it is invaluable as a confirmation of fuel gauge readings. Many engine problems are easily diagnosed with a fuel flow gauge, but tough without. I'd recommend it.
 
I added one in May and would not be without it now. It is very accurate and I know what I have for fuel and also endurance time continuously. It gives me accurate information to make decisions early in a long flight.

It is especially important because the fuel level gages are not accurate above or below certain fuel levels. Fuel flow is accurate regardless of the level of fuel in the tank.
 
I flew my old Yankee around for 23+ years with nothing but the worthless sight gauges, my knowledge of it's normal fuel burn rate, and a wrist watch. Travel, IFR, everything. Did it all the time. Now that i have fuel flow and all of the information that it provides in the RV, I wouldn't want to be without it. Like XM weather, moving maps, and GPS, Fuel flow increases your situational awareness to an extent far in excess of what it costs.

If all you're going to do is fly locally for an hour at a time, a clock is fine - if you're going to utilize your RV for travel, Fuel flow is a huge plus.

Paul
 
Notes from the Field

I refer to the fuel flow indication quite often in my fixed pitched equipped RV. I like it very much. Even on local flights with no particular place to go, I like being able to lean the mixture and instantly see what the fuel burn is being set at. I usually see a full rich mixture condition at something exceeding the 9 GPH. As I proceed to lean the mixture, in real time can observe the fuel flow reducing even as I unwind the mixture control knob. I usually set the engine to burn around 6.7-6.9 GPH while in the 2400 RPM ballpark range. The VM-1000 via its optional EC-100 constantly recalculates the remaining fuel and will display that information as FUEL FLOW and FUEL HOURS. In effect, this acts as a sort of electronic fuel gauge and I find that when refueling the plane, the VM-1000 engine monitor and the totally independent EI Capacitive Fuel system gauge do tend to agree with one another. However, for the fuel data calculations to be accurate in the VM-1000, it is vitally important to remember to manually reset the total number of gallons of fuel known to be on board because the engine monitor is a computer and as we all know, garbage in....garbage out.

A fuel flow indication in whatever form you choose to buy and use it is very useful auxillary information. I don't think you will be dissapointed in its utility and usefulness.

2ef0uv9.jpg
 
Really interesting thread.

When I finished my -6 in early '93, virtually no one had fuel flow gauges in experimentals. Only a few in "spam cans".
My friend Gene Plazak had developed one for his Yankee. I installed one in my -6 primarily to be different. Soon after I had flown with it, I vowed that I would never have an airplane without one. And looky, looky, now everybody has one.
 
any pros and cons between the Red Cube and the Floscan? Apparently Dynon has switched to the Red Cube, but either will work.
 
Mel said:
When I finished my -6 in early '93, virtually no one had fuel flow gauges in experimentals. Only a few in "spam cans".
My friend Gene Plazak had developed one for his Yankee. I installed one in my -6 primarily to be different. Soon after I had flown with it, I vowed that I would never have an airplane without one. And looky, looky, now everybody has one.
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Got you beat, Mel. Flow Scan has been around for quite some time. I used an auto system in a LEZ in the 80's and in a Cozy in 90's. Both worked well with low fuel pressure carburetored engines even with the scan device before the fuel pump.

The accuracy of these systems is amazing. They keep track of fuel used, current fuel burn and can be used to set percent of power. I have a spread sheet that computes burn at a specified BSFC and calculated percent of power based on specified gallons per hour. For example, ten gallons per hour comes in at 65% power.

I wouldn't be without this information....
 
prkaye said:
any pros and cons between the Red Cube and the Floscan? Apparently Dynon has switched to the Red Cube, but either will work.
Click to expand...

Red Cube is said (By the EI tech support rep that frequents here) to be much less subseptible issues with the way it is mounted and the fittings/lines/bends coming in and out of the unit.

The Cube is also a big chunk of aluminum where as the Flow Scan seems to be some sort of casting. I have heard that it is easy to break the the Flow Scan by too much torque on the fittings.

Some say the Flow Scan can be more accurate but I say that that would be very subjective and many variables would play into that fact.

The Red Cube does have a gasket and plate on one side of it that could leak air or fuel and if you were sucking fuel thru it, that might cause you to lose fuel pressure. The EI guy says to always push fuel thru it.

The Red Cube seems to be easier to mount to stuff because of its shape.
 
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Mel said:
When I finished my -6 in early '93, virtually no one had fuel flow gauges in experimentals. Only a few in "spam cans".
My friend Gene Plazak had developed one for his Yankee. I installed one in my -6 primarily to be different. Soon after I had flown with it, I vowed that I would never have an airplane without one. And looky, looky, now everybody has one.
Click to expand...

*********************

Wow ... there's a name from the past. As a former AYA member who attended a couple of annual conventions in my AA1-A, I remember Gene for his tailwheel conversion and speed mods.

Funny how many RVers I find as time goes by who used to own Yankees of some variety. Like old home week ... :D
 
Brantel - I have the flowscan unit and it is accurate to .2 gallons over 30 gallons of fuel burn. Not any big deal to mount, although may be a little harder because of the shape.

There's nothing wrong with a casting. It allows the engineer to put more material where it's needed.

I don't know if it would be less accurate in other installations. I managed to get about 3" of straight run before and after the unit.
 
Put in a Fuel Flow - you'll be glad you did. At current AvGas prices when people ask my how fast my RV cruises, I usually say "7.5 or 8.5 gph". Whatever that equals in speed that day is what it is!

Regarding the difference between the FloScan an the EI, the EI is a bit better of a unit to be quite honest. It's calibration is better from the factory, it's less suceptible to mounting irregularities, and lastly EI as a company is some of the nicest folk aroune (and they support our VAF group).

All things being equal, if I had a system that would use either I would choose the Red Cube. Of course I've been flying behind a Floscan for years without any issue at all - so they are fine too.

My 2 cents as usual!

Cheers,
Stein
 
I must be on the other end of the scale.

I have the FFS in my RV but never used it. One of the reasons is that the Dynon capacitance fuel level sendors are so accurate that I learned to rely on them.

Remember, if you develop a leak, that fuel will not go through the FFS, so it will not be deducted from your total availble.

Truth is, a lot of the things we put in our planes that we "can't live without" aren't needed. Just go fly an old C65 powered T-Craft, Cub, or Champ and you will quickly find out what I'm talking about.
 
N941WR said:
I must be on the other end of the scale.

Truth is, a lot of the things we put in our planes that we "can't live without" aren't needed. Just go fly an old C65 powered T-Craft, Cub, or Champ and you will quickly find out what I'm talking about.
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Now you know..............the reason that I can beat 0320 powered RV9's in fuel efficiency with my "heavier" 0360 RV6A is the fuel flow sender. :) That, in addition to leaning, adjusting the C/S prop, and manifold pressure is the key to it all! :D Yes, I have to know exactly what my use is per hour.

P.S. --- I read about a new airplane in which the owner and instructor were grabbing on to the top of the wing for additional height, to see how long the taxi line ahead of them was. It was after an airshow. Seems they'd hold on to the gas cap, which loosened it, and ultimately came off. One of them believed the fuel full gauge while the other noticed the fuel gauge quickly diminish. In this case, the fuel gauge was correct, and the plane made a bad crash landing. So you are correct..................look at the fuel gauge too!

L.Adamson ---- RV6A
 
how to mount the red cube

Does anyone have pictures of your red cube install? I am working on this install now in my 9A. I had planned to mount the floscan under the center cover just in front of the firewall somewhere. However, if I mount these red cubes there they are taller than the cover so I would have to devise some additional cover plate. Another issues is how are they mounted? I know they have two holes for placing a bolt through them but where does the bolt mount to in this location? they are only resting on the belly skin in this location. I have no desire to drill through the skin and have a bolt or nut plate hanging in the breeze.

Any assistance would be appreciated from those who have been there before me.
 
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