9A tank capacity

Van claims the 9A to hold 36 gallons of gas with each tank holding 18 gallons. Lately I've been doing endurance testing to see just what the plane will give me for differing settings. Today for the first time I ran a tank dry and the engine let me know that something had to change or we would be landing soon. This is the first time that I've ever done this in anything that I've flown and had the big eye waiting for the engine to sputter. Well, there was no sputter! The sound just changed and the plane rapidly slowed. As quickly as I could move the fuel selector to the other tank and turn on the boost pump the engine started running. In fact the boost pump might have played no part in returning the engine to life. This was no big deal and if there is a need to have all of the fuel in one tank on a long trip this would not bother me at all to do again. There was no warning of a fuel starvation by a fluctuation in fuel pressure, just simply the fire going out.

So, how good are Van's numbers on fuel capacity? With all usable fuel burned off the tank took 18.1 gallons to the bottom of the filler neck. Just another example of Van providing real numbers.

Best,

When the big fan up front quits, it definately gets your attention.

After draining my tanks I can get 19 gallons back in.

usable fuel ?

Hey guys, I'm installing new fuel tanks on my 10 yr old RV-6.
also installing a EI digital fuel gauge and using capacitive senders.
when calibrating, it says to start with usable fuel. Well, I've had the tanks off the plane for months (empty fuel lines) plus the new tanks are bone dry.
Should I add some fuel, level the plane, etc...then use the boost pump to pump the tank down to empty at the gascolator. That way it duplicates running dry and would be the beginning or end of 'usable' fuel...

Seems there could be an arguement made for usable fuel would mean until the engine quits and would include fuel in the lines and carb, but I think I am overthinking this and really no way of allowing for this except for letting the fuel line and carb fuel be part of the safety margin.
Any thoughts?
Thanks,

tip tanks

I was considering building a 9A, but one built by a man who had built 10 other homebuilts just became available and i bought it. It has the Titan 0360 with blended airfoil cs prop. I would like to install additional fuel capacity and prefer tip tanks. Does anyone know whether that can be done without tearing the wings apart and who might make the tanks? thanks

Fuel capacity

I have been concerned to fill to the base of the filler neck for fear that when climbing out (pitch up) that the air vent tube might get flooded. Not sure if this is a well founded concern. Still in phase 1 and yet to determine exactly where 18 gallons will bring the level from the filler neck. The precision gage reading is on my to do list.

May be others can chime in here.

Jim

Tanks

I've got SafeAir 1 tanks in my -6. Easy install and they work great. 4.4 gallons per side, no extra pumps required. Not sure if they're making tanks for the -9 but it's worth a call to find out.

a couple options....

karl said:

I was considering building a 9A, but one built by a man who had built 10 other homebuilts just became available and i bought it. It has the Titan 0360 with blended airfoil cs prop. I would like to install additional fuel capacity and prefer tip tanks. Does anyone know whether that can be done without tearing the wings apart and who might make the tanks? thanks

Click to expand...

Karl, I'm certainly no expert on this, but might be able to help summarize.
You have the 180 hp, but if you want more RANGE, then you can go higher, which the -9 is good at, and pull the black knob back a bit, say 55% power, and far outrun your bladder!
Adding tanks to a completed airframe is harder....the SafeAir basically runs a tube down the big hole in the nose ribs, thus only 4 gallons or so. ( but hey, 8 gallons of useable is another hour!)
Most guys do it while building, making another one or 2 bays of the leading edge 'wet'.
Tip tanks require more plumbing and management as a rule, and there seems to be a void where one might expect aftermarket suppliers to provide something. Trouble is, the -9 has a unique airfoil, so the market is limited.

Then you have your drop tanks, cabin tanks, air-to-air refueling probe..... that type of thing....which becomes a real engineering & plumbing adventure,......
if you like that??? go for it!

Jeff & Chuck, the Hotel Whiskey guys, build the ER tanks sold by SafeAir 1.
They do build ER tanks for the -9.
Not sure exactly how much they hold but the ones on my -6 hold 4.4 gals each. The goal is to add a little over one hour range for each aircraft.

Great Work Bryan

The sound just changed and the plane rapidly slowed. As quickly as I could move the fuel selector to the other tank and turn on the boost pump the engine started running. In fact the boost pump might have played no part in returning the engine to life. This was no big deal and if there is a need to have all of the fuel in one tank on a long trip this would not bother me at all to do again.

Click to expand...

Well done.

We teach about this and long range work in the APS classes and we demo it in flight. It is no big deal. Done properly not at 100' on climb out it is a non event. In fact it was SOP on the big piston airliners every flight.

Until you run a tank dry....you only think you have XX gallons, you do not know.

At the end of a max range flight you want to have all but the last tank dry. And all your fuel in one place. If you had to hold for an extra 20 minutes while a disabled aircraft was removed from the field, you would not want to be scratching around sucking the last few litters out of several tanks then making a landing. Especially in IMC.

And for anyone with a flop tube, do it often.

Great work and you are now a safer pilot for it.

Options ...

Mel said:

Jeff & Chuck, the Hotel Whiskey guys, build the ER tanks sold by SafeAir 1.
They do build ER tanks for the -9.
Not sure exactly how much they hold but the ones on my -6 hold 4.4 gals each. The goal is to add a little over one hour range for each aircraft.

Click to expand...

As Mel mentioned here, there are wingtip options from at least SafeAir.
I know you said that your **preference** is for wingtip tanks.

If you decide to consider other options, I installed two (2) "behind the seat" tanks from Marvin. They have 7 gallons each. I use one for smoke oil and the other for fuel but they could be tied together for 14 usable of fuel.

I worked with Marvin on a design that will fit the 6, 7 and 9, either slider or tip up. The installation is not too bad and I can send you some pictures if you contact me offline.

There are obvious advantages to the wing tip tanks but if you decide otherwise, I wanted to pass on that there is another approach that you can take with the 9.

James

After putting over 600 hours on my -9 and looking at all the long range tank options, I would go with the behind the seat option James mention.

However, if my plane wasn't painted, I would order another set of tanks from Van's and cut them down to the size I want/need and install them outboard of the stock tanks. Plumbing would be with a five way Andair valve and I would do a coiled vent line outboard of each tank. Where the two tanks come together I would make the entire leading edge section removable.

Just another thought.

Without any extra tanks, I have found flying high with oxygen you can get some amazing speed and fuel flow numbers while heading east. Heading west, not so much.

ER Tanks

I have a set of Jeff & Chuck?s (the Hotel Whiskey guys) ER tanks sold by SafeAir 1 in my RV-9. I haven?t flown yet but I am told they hold about 4.5 gals. There are two small transfer pumps that transfer fuel to the main tanks. And it is my understanding these can be installed after the plane is complete.

We ran each tank dry While on the ground) in order to calibrate each tank and when we used the strainer, we only got 1/2 strainer of fuel left in the tank. These are effecient systems that leave very little fuel. I was expecting like a 1/2 gallon or so.
Pat Garboden
Katy, TX
RV9A
N942PT