WingedFrog

WingedFrog

Well Known Member
There have been a lot of critics about the sight windows in the fuel tank, to the point where some have decided to close them after putting some other device as substitute. After a few weeks of flying, I have come to the conclusion that these little windows are very useful and, IMHO almost irreplaceable. Indeed, as a pre-flight check item, it is the only measurement of fuel that is 100% trustworthy. Contrary to what some have claimed, it is not that difficult to read: from behind the left wing with the help of a good flash light. It is very precise with 33 windows covering 20 gallons, this is less that 1 gal per window. Reading the windows in flight? Nonsense if you did your job in preparing your flight. Even in case of inflight failure of either the tank gauge or the fuel flow meter, there is enough redundancy with these additional devices to determine what the problem is and if both seem to fail at the same time, you will not need to look at the window to know that you have a fuel leak and you better get on the ground in a hurry. I admit that a gauge that can be visualized while refueling may be useful but if it is based on a float as the Moeller gauge is, it will not be precise enough for the last gallon and you still will be at risk of overflow if you are not careful when close to full tank.
In conclusion, I am puzzled that VANs fell under the pressure of the Moeller gauge lobby, their window sight is unbeatable in simplicity and it will never lie about the amount of fuel in your tank: KISS! :p
 
Van's Can't Win

I'm chuckling over this thread as for the last several years posting after posting complained about the lack of a Moeller gauge in the -12 fuel tank. I'm building under E-LSA so I held off adding one myself, (even with all the peer pressure to do so.) Now that Van's responded to all the lobbying by adding one in the latest tank design, the VAF pendulum is beginning to swing the other way.

I have more and more sympathy for Van's every day!
 
When flying x-country my luggage compartment is always full blocking the window. Talking about KISS; the Moeller gauge is easier to install than the window (without leaks).
When refueling I use high flow to fill the tank until the Moeller indicates full and thereafter I reduce the flow for the last liters (+/-7 liters). How to do that if you can't see the window during refueling? If there is a lot of noise on the apron and you can't hear the "gorgle" you don't have any clue how full the tank is (when refueling alone).
When I check the fuel during flight I can also check the Moeller to verify the amount displayed on the Dynon. Easy to see over you shoulder.

I don't regret installing the Moeller. Further I don't think Van's is sensible for the "pressure" of the Moeller gauge lobby, I think they are good listeners and only change something after careful consideration.
 
It may work for you but not for me!

We live in a land of varied opinions or better know as the land of the free opinions. What one perceives as acceptable another one may not. May I suggest a poll to which you may be surprised at the results.;) I for one love the moeller gage and don't like the sight gage. When in the shade of the hanger using premium unleaded gas which is clear it is hard for me personally the see it in the window unless I dig out a bright flashlight. I understand the window is for preflight. But with the moeller in flight if everything fails on a long x-country all I have to do is look over my shoulder to verify fuel in the tank. Also when fueling a quick look at the moeller gauge tells you when you a getting full to slow down in order to not overfill and ruin you know what.:mad: Also in the beginning after some planes were built the material in the window cracked and had to be replaced with a different material. Some people hated going back into their tanks and this left a bad taste for them. :( It's really all about perspective) :rolleyes:
If you fly several hops a day ease is where it's at. If you fly once a week get the tube out drop it in or grab the flash light. Oh look! Its leaking dam it this time I'm sealing it up for ever! Get my drift! :)
 
Not exactly

NASA515 said:
Why do I get the feeling this forum is re-plowing the same field over and over again? Sometimes in quick succession?

http://www.vansairforce.com/community/showthread.php?t=103199

Bob Bogash
N737G
Click to expand...

Not exactly Bob, your thread is all about the Moeller gauge, my point is "Fuel Tank windows are good for you", don't bother messing with your fuel tank to install the Moeller gauge, you will get little added value.
 
gossend said:
I'm ambivalent on this.......but I feel strongly about both sides!:D
Click to expand...

I'm undecided about whether I'm abivalent about your opinion. :D

BTW, I did not install the Moeller gauge but I think the design of the site gauge makes it prone to leaking.
 
Very pleased with my modded tank from Vans

Well, I want to say that I am very pleased with the modded tank from Vans I rec'd in my finishing kit, and I certainly appreciate all the builder's efforts to improve the design and modification of the many things that I have noticed have been changed and improved by Vans.

I think this effort by the manufacturer to constantly re-design and improve their aircraft has been one of the few bright lights in an otherwise mostly dying gen av industry.
 
As William Shakespeare said "Is most tolerable, and not to be endured.
Much Ado about Nothing. Act iii. Sc. 3."

It seems most that have been flying for a year or two cover it up, and put in a Moeller.

Hey, if the original works for you, go for it. I personally do not like lots of extra places for fuel to leak, and hate the smell of leaking fuel in flight.
 
fuel leak

if the reason for covering them up is fuel leaks what about the rest of the tank, just as much chance of a seam leaking as the sight glass or am I missing something
 
crashley said:
if the reason for covering them up is fuel leaks what about the rest of the tank, just as much chance of a seam leaking as the sight glass or am I missing something
Click to expand...

Have you built a RV-12 tank yet? That site gauge is a little complicated to assemble while smearing tank sealant around. There's more than a dozen screws, the plastic sheet, a cover piece on the inside, all assembled at once with tank sealant everywhere, while you're trying to keep it off the little windows. No doubt it's the most prone to leak just with the number of places it COULD leak.

The rest of the tank is a piece of cake because unlike the other RVs, you put the sides and bottom on before the top so you can reach inside the tank and smear tank sealant wherever it's needed BEFORE you seal it up. Easy peasy.

I suppose the tank cover is also a place where leaks can occur for the same reason as the sight glass but it's also easier to assemble.

I'm not particualrly for or against the sight gauge/Moeller gauge. I think there are pros and cons each way. The Moeller is probably easier to install, less prone to leak, but it is mechanical and can fail so it needs to be verified, at least occasionally.

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fuel tank

yeah I have built a tank and luckily I have not had any leaks and over 300 hours flying with it now
flys great and I love it but a bigger fuel tank would be really good
as I often have to divert during flights to get fuel
as a lot airports here don't have fuel available
 
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