More fuel?

[RV8Squaz]

I know there are a lot of reasons for and against adding aux or long range tanks to the RV's. This is simply another data point for those considering or on the fence about adding them:

I have the standard fuel tanks in the RV-8, 42 gals total. I just got back from San Antonio. I flew non-stop from San Antonio TX to Valdosta GA (804 nm) in 4.1 hrs including an extensive re-route south of the Houston class B. I was flying at 11,000' , 173 KTAS, and winds were from the west at 20 kts for the first half and 35 kts for the second half. My power was set at full throttle (or about 20" MP) and 2550 rpm. Fuel flow was 8.2 gph and ground speeds were anywhere fom 193 kts to 210 kts. I landed with 6 gals. or about 40 mins. of reserve.

I hope this helps anyone considering adding more fuel to the RVs.

Jerry

[Mark Burns]

Jerry,
That's good information.

Do you have fuel injection?

When running the fuel that low do you run one tank dry and then have the 6 gallons in the other tank? If so, is the preference to use the right tank for the last of the fuel? Seems like that would feed better making left turns in the pattern.

I know 6 gallons is 40 minutes but in the spam cans I rent I'm usually hauling around 30+ gallons for a 1 hour flight! I think 6 gallons would make me a little nervous. (until I got used to it)

Mark

[Mel]

Originally Posted by Mark Burns

Jerry,

When running the fuel that low do you run one tank dry and then have the 6 gallons in the other tank? If so, is the preference to use the right tank for the last of the fuel? Seems like that would feed better making left turns in the pattern.

Mark

If the airplane knows which wing is low, you aren't coordinated.

[dan]

Originally Posted by Mel

If the airplane knows which wing is low, you aren't coordinated.

Thanks, you took the words out of my mouth. But if you're slipping on final with only a handful of gallons left...be careful! Hope you NEED the slip.

[pierre smith]

How many of you guys have run the airplane dry or very close to it on one tank? Do these airplanes feed just about all of the gas? I've run my -6A down to 3 or 4 gallons in the wings and it never sputtered but I've often wondered.

In the AT-6, I used to alternate from one tank to another every half hour and when the one side ran dry, I'd know how much time remains in the other side. Do any of you guys do this with your RV's?

Thanks,
Pierre

[dan]

Originally Posted by pierre smith

How many of you guys have run the airplane dry or very close to it on one tank? Do these airplanes feed just about all of the gas? I've run my -6A down to 3 or 4 gallons in the wings and it never sputtered but I've often wondered.

I've run both of my tanks dry on different tests & flights (obviously!). With flop tubes I had 0.3 gal unusable in each tank.

Last time I ran a tank dry was on a long trip with my wife. When the engine sputtered, tears ran down her cheeks. I had told her up and down what was gonna happen, and she knew it was gonna happen, but it still scared the carp out of her. Never again with wifey poo onboard.

[Mel]

I ran both my tanks dry (one at a time) during testing. With the standard pick-ups, I found no difference between draining the tanks and running them dry. 19 gallons either way.

[RV8Squaz]

Mark,
Yes, I do have fuel injection, a 200 hp IO-360A1A. I ran the right side down to about 1 gal. remaining and the left had 5 gals. The reason I kept more fuel in the left v.s. the right is because my airplane is slightly right wing heavy. The aileron trim is neutral when I have about 5 gals more in the left than the right. The other reason I left more fuel in the left wing is because I don't know what my unuseable fuel in either tank is in a nose low attitude typical of a 1000 fpm descent.
I didn't feel comfortable running the tank completely dry. I am a 7000 hr AF pilot and "shutting down" my only operating engine just doesn't seem like a good idea. I have a VMS 1000C with capacitance senders and a very accurate fuel computer. I have verified the accuracy of both the fuel gages and the fuel computer. I switched tanks when the fuel level went from 2 to 1 and fuel computer indicated 1.3 gals remaining.
I have also verified the unuseable fuel quantity in a level attitude. I did this prior to my first flight by disconnecting the fuel line going to the fuel servo and running the boost pump 'til it quit flowing. I then drained each tank meausuring the quantity I drained. On the right with a standard pickup tube I got 7 oz. On the left with a flop tube I got 13oz. I have a lot of confidence in my fuel system, but I also still rely on my watch.

Jerry

[pierre smith]

Originally Posted by Mel

I ran both my tanks dry (one at a time) during testing. With the standard pick-ups, I found no difference between draining the tanks and running them dry. 19 gallons either way.

I can see doing it once to verify feed factors and so on but I now try to avoid running dry because of the shock cooling on colder days.

Thanks guys,
Pierre

[Mark Burns]

Originally Posted by Mel

If the airplane knows which wing is low, you aren't coordinated.

I hadn't thought of that....DUH!

If you sideslip due to a crosswind with low fuel you had better think hard about it. I guess a crab to very short final would be safer in this instance.

Mark