Nonstop KPAO to KAPA

This is probably not as thrilling to others as it is to me, but I was completely surprised. I learned some things about my airplane and it forced me to expand my fuel management skills.

825.8nm
5.4 hours
32.48 gallons
ind alt 15,500'
DA ~17,400'
TAS ~ 147

I had planned a fuel stop at KDTA, but before I got there I noticed my fuel burn was well below plan. After crunching the numbers I realized I could make it all the way to KAPA with acceptable reserves. My estimate was that we would make it with about 45 minutes reserve, maybe up to an hour.

I had ran the left tank dry near KEGE. On landing we were showing about 4 gallons remaining in the right tank. The fuel fill implied we had only 3.5, but I think the tank holds a bit more than 18.

Our average fuel burn was 6 GPH, including climb, so even 3.5g was greater than 1/2 hour reserve. We lost some of our tail wind on the second half of the trip that ate into our margins.

Some notes:
I've been experimenting with running LOP for the past few months. When the MP is pulled back to an inch or two below max it works great. For this trip I only pulled back a bit more than 1/2 inch. My leaning procedure was not very scientific. I leaned until roughness, then enriched it just a bit. I noticed this was just LOP on #3, which I think was my leanest cylinder.
**
Running a tank dry was a first for me. I was a bit apprehensive, but being within glide of an airport made it emotionally easier. When I was showing about 1 Gal remaining, I switched on the fuel pump. When fuel pressure started to drop I switched tanks. To my delight the engine never missed a beat.

My wife was not happy with this procedure at all. Adding to the apprehension is that it ran a long time, maybe 10 min while pegged at zero. Anyway, it had to be done. Using all the fuel in that tank is what allowed having acceptable reserves on arrival. Now that I've done it, I wouldn't hesitate to do it again.

Another note on this procedure: pay attention to the fuel pressure gauge! I was watching it close and got distracted by ATC. I heard the pump struggling and by the time I looked at the pressure it was falling fast. Not a catastrophe if the motor quit momentarily, but its drama I don't need.
**
I've been checking the fuel gauges on this airplane since I bought it. They are very accurate. That gave me the confidence to use them for in flight fuel planning
**
The GPS496 is what tipped the balance on making this trip non-stop. Otherwise, I wouldn't have had the nerve. Continuously updated ETE + weather. Weather means wind, so I new what to expect. We also had to skirt several small thunderstorms. The XM weather allowed doing that, and in an economical way.

So, can your wife give my wife lessons on how to avoid a DEfueling stop on a 5+ hour trip?
Car or plane, 2.5, 3 max is all I can plan for.

Charlie

"Travel John"

rv7charlie said:

So, can your wife give my wife lessons on how to avoid a DEfueling stop on a 5+ hour trip?
Car or plane, 2.5, 3 max is all I can plan for.

Charlie

Click to expand...

We filled about 4 of those altogether on this trip. The gel is due to chemical reaction, so up where its cold let it sit on the glare shield in the sun before using. Otherwise it takes a long time to gel.

My last airplane (M20J) had very long legs so it forced us to perfect the in flight relief technique. It takes practice and planning.

-Avoid turbulence. do over flat rather than mountainous, in clear sky areas rather than under cumulus clouds.
-For the pilot, go right after a frequency change. Otherwise I've found that invariably they give me a freq change right in the middle
-Make rules about when, because it causes a little chaos in the cockpit. For me that's level cruise only

My wife has no problem doing it, but she had to learn to plan ahead since at some points in the flight she has to wait.

Steve Brown said:

My leaning procedure was not very scientific. I leaned until roughness, then enriched it just a bit. I noticed this was just LOP on #3, which I think was my leanest cylinder.

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Are you sure you are LOP with this technique??

What do you have for EGT monitoring?

Is there a web based program that will tell me what airports kpao and kapa are that you guys like to use?
palo alto to arapahoe county colorado?

and what oxygen system are you using?

what is DA?

Airports and stuf

Danny7 said:

Is there a web based program that will tell me what airports kpao and kapa are that you guys like to use?
palo alto to arapahoe county colorado?

and what oxygen system are you using?

what is DA?

Click to expand...

Those are the right airports:
http://www.airnav.com/

I think my O2 is 24^3 feet. It is a 4 place system, but obviously I only use 2 now. We use cannula

DA is density altitude

A meter that reads EGT

Mike S said:

Are you sure you are LOP with this technique??

What do you have for EGT monitoring?

Click to expand...

This was LOP on at least one cylinder. Since I have a switch between cylinders its difficult to tell what happening on the others.

running tank empty

steve, i always run a tank dry on long legs where i dont want to leave any fuel in the tank. my tanks were set up to have 2 gal left when they read 0. knowing my fuel burn i watch my egts which start to fall off when the tank is empty. the engine doest quit. i did this last month running from hartford ct khfd to columbus co sc kcpc. i had 4 gal left. next stop was stuart fl ksua. my burn at 150kts tas is 8 gph leaned to rough then 1 1/2 turns in. keep on flying. my hobbs turned over 3,300 hrs on my last trip which covered 13,000 miles. fl/ca/fl/ct/fl. ;love these rvs.

Steve Brown said:

This was LOP on at least one cylinder. Since I have a switch between cylinders its difficult to tell what happening on the others.

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O.K., makes sense, by your signature block it appears your a/c is carb, not FI.

Coupled with limited EGT monitoring,I think you are doing it the right----read as safest---way.

How does she do it?

My wife has no problem doing it, but she had to learn to plan ahead since at some points in the flight she has to wait.

Click to expand...

OK Steve,

Longest flight my wife and I have made to date was 4.2 hours. She has the smallest bladder on the planet so I try not to plan for more than 3 hour legs. My wife has tried and just can't seem to overcome some of the obstacles in the way. Mostly the stick, but postioning is difficult also. Curious which gel pack/system are you using for this? Our wives need to talk.
I have no problem with the little john and agree with you on your rules for going.

Remove the stick

339A said:

...Mostly the stick, but positioning is difficult also. Curious which gel .......

Click to expand...

My copilot stick is removable. We pull it out when my wife goes.

Literally - "Travel John"
http://www.traveljohn.com/

Also available from sporties

Kind of an strange subject, but its impossible to finish long legs without dealing with this. also a bad idea to limit fluid intake when flying high.

Go Lean or Go Home!

Steve,

Great trip! I run my -9a the same way. Try adding some carb heat and I'll bet you can get all the cyls LOP. At 7500 or above we get 145-147 KTAS on 5.5GPH, The higher, the better.

It is not the fastest RV travel, but it is pretty effcient!

I have not run the tank dry yet, I might try that. My personal min for fuel at destination is 7gal - I could probably reduce that, but have not needed to yet. The Dynon EMS constantly computes remaining fuel at destination, making this easy.

Here is a flight this winter - cold outside, but running lean with carb heat.

petehowell said:

....At 7500 or above we get 145-147 KTAS on 5.5GPH, The higher, the better...........

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according to your EMS your burning 5.2!!! nice, and calculated by the numbers on the screen, that's ~145.6KTAS

what engine are you using?

0-320

Hi Ian,

I run an O-320, carb, Hartzell and dual EI, similar to Steve(diff prop). I was just trying to show the Dynon display here. I'll be honest I don't know the TAS when this photo was taken and you need to consider wind effects - I can tell from the MPG that at this point we had at least some tail wind(MPG is based on ground speed from the GPS). 5.2GPH will get us better than 140KTAS, but not 145+ in still air. On a long trip, we search the winds aloft for the best situation (25-26 nmpg) if the weather permits. If you have a headwind, well....

Guys with FI can match or better these numbers - but IMHO it is the EI that really lets you run lean. You just need to be willing to experiment with carb heat and throttle position.

Works both ways

Made the return trip, APA-to-PAO, nonstop today.
It took a bit longer working against prevailing wind, 5.9 GPS flight hours. Fuel burn was only a bit more: 32.8 gal. The tank with fuel remaining took about 14.65 gal.

That works out to about 5.6 GPH total. Better than the trip out, because I started aggressively managing fuel right from the start:
Filled both tanks to the brim right before takeoff.
Ran on the right tank until just after takeoff, then switched to left. I wanted to be sure I didn't vent any fuel due to heating.
As temperature, pressure, and weight varied thought the trip, so did exact settings, but this was the approximate:
16.5"
2500 RPM
TAS 144
14,500' indicated
16,100 DA
IAS 115

Since the throttle was pulled back a bit more (@14.5k verses 15.5k), I was able to run LOP on at least 2 cylinders.

FYI: This time I ran the right tank dry and it flew for exactly 8 minutes between "0" and when the fuel pressure started to drop.

Even though it meets legal VFR minimums, I must say I'm not thrilled about landing with just over 3 gallons of fuel. I had to stay on top of keeping this thing leaned to "within an inch of its life" right up until I leveled of at 1000 AGL at PAO. Every time I passed an airport during decent I went though a little emotional struggle in deciding if it was safe to continue. I guess I'm a fuel wimp.
I'm still going to need some extended fuel to make this trip reliably non-stop. I used to wonder if 10 gallons extra would be enough, but now that seems like more than enough.

I would not want to land with only three gallons. Not a prudent way to fly IMO.

Have to agree here

I have never heard a "good" reason for running out of fuel over the contiguous 48 because there ain't one.

Great traveling machines we have but they all have limits.

I ran a tank dry

by accident once. Talk about a wake-up call! I was westbound south of Chicago, low to be under the clouds and headwind, about 1300 AGL, keeping very busy looking for all the towers and tracking obstacle alerts. All of a sudden the engine goes south! I don't think it took more than about three seconds to turn on the boost pump and switch tanks, but it seemed to take forever (maybe ten seconds) for the engine to catch fully again, meanwhile I was climbing and looking for a place to land.

Hans