That's an estimate to dry tanks... so if you do it, you better be within gliding range of something :)

Either way, the number is accurate. Can't speak for a 320-powered 7A, but my 7A w/ a 360 would do it.. I wouldn't but the plane was capable :) Figure 5.5 hours to dry tanks.. I'd never wanna sit that long, and you'd want some reserves obviously..
 
Yup, physical comfort is probably the limiting factor unless you have an in flight relief system of some sort. An extra stop will often also help with pilot fatigue on longer flights.
 
PBFNINO Range

I don't think the average sunday pilot like me does.

I'm sorry but I have to expand on the answer because I feel this is such an important subject.

I flight plan for a 11 gallon per hour burn rate and 150 kts with 1 hour reserve then if I see I have significant fuel left I will extend to a comfortable distant intermediate stop. Winds are a big factor. I have two configurations of fuel tanks 55 gallons (4 tanks) and 38 gallons (2 tanks). My burn rate at 75% power is 10 gallons/hour at 2450 rpm and that is my normal cross country cruise configuration. For racing at 2700+ rpm my burn rate is 14 gallons/hour. Saturday in the two tank configuration I flew the 143.5 nautical mile race organized by Craig Taylor at Pagosa Springs, Colorado then pulled the rpm back to 2450 and continued on to Tucumcari, New Mexico via E14 (Espanola, NM) before landing to refuel. That distance is 363.5 nautical (sea?) miles and my logged flight time for that distance (race and first leg home) was 2.5 hours (started engine at 10:36 and landed at 13:04). As I said at the beginning I plan on my demonstrated burn rate plus one gallon per hour and plan to land with approximately one hour in the tank with a ground speed that is lower than normal. I would NEVER plan based on the the factory range to tanks empty - to me, that is just a random number. I think I am fairly conservative in my fuel planning but even given that, I once had to land at an unmarked (on the sectional chart) airport because of low fuel.

The comfort thing is something I can't afford - when I'm flying I'm going some place and I don't want to be piddling away my time. Different strokes, etc. In our RV-6A with a O-360-A1A I have flown from Panama City, FL to Fayetteville, Arkansas and from Sheridan, Wyoming to Hutchinson, Kansas and Boise, Idaho to Cheyenne, Wyoming for example without refueling but I plan conservatively and pay attention to time, fuel gauges, ground speed and airports.


Bob Axsom
 
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Range

With our 0360 in the RV7a.

4 hours at ~9 gph at 185 smph equals 750 s miles with 1/2 hour reserve. Winds are the big key. Our GRT has a totalizer and constantly calculates remaining time and range which really helps. Farthest non-stop for me has been 3 1/2 hours and the plane held 29 gallons after that flight so 4 hours is just about right in VFR conditions as a max.

The fueling area at our field is not level so it can be tricky to get the tanks 100% full. We usually tell the GRT it has 40 gals instead of 42 after a fill-up but to be conservative.
 
We did 668 nautical in a little more than four hours the other day with calm winds coming back from Deming, NM to our home south of Houston. The totalizer had us with 10 gallons remaining when we landed, so we could have flown another hour and a quarter to dry tanks. We use in-flight relief packs if required to save a descent and climb from/to 11,000+ on these trips - that can be 45 minutes with a fuel stop, and a lot of hot climbing on the engine.

All a trade off, but yes - you can fly a LONG ways if you are motivated!
 
1020 NM here

Our -7 has a Extreem IO-360 with dual P-mags and we normally fly X-country at 55% pwr (21'/2100 RPM),
We fly at 50*F LOP which gives us a fuelburn at 22 litres (5,8 US GLS) pr hr.

That gives us beetween 125 and 130 KIAS, depending of GW.
At 8000', that is 140-145 TAS.
These figures gives us a range of 890 NM with 20 litres in reserve.
The range to dry tanks with these settings is 1020 NM.

Ofcourse we never fly this long; mostly our legtime is beetween one and two hours, but the nice thing about the long range, is that we don't have to think about refueling until after several legs.

We never fly fast during cruise, because flying X-country for the wifey and me is like when we are sailing: the real joy is the trip itself, not getting there... so why hurry to get on the ground somewhere? It's much more fun to fly ... :)
 
Like others, physiological reasons limit us more than anything.

818 NM is our longest nonstop leg. Double Eagle west of ABQ to Kennet MO. with reserves but we were racing the sun that afternoon. Headed east in the winter makes for short days.
 
My RV-7 / IO-360 with one Lightspeed and one mag cruises at 8500' at 6.9gph for a TAS of 180mph. My Dynon tells me that I have over 1000 mile range!

Not quite gas mileage or range related, but here's something to think about...

Last month I made a flight with my wife and full luggage from Provo, UT KPVU to Arlington, WA KAWO. We flew this flight non-stop, and not quite straight (followed major hiways and avoided fire TFRs) for a distance of about 700 miles. The flight took 4 hrs 15 min, and I landed with about 10 gal. of fuel remaining. I had headwinds which slowed me down.

Prior to this flight, my wife and I drove her 2010 Hyundai Genesis for a two hour drive from Logan to Provo.

We both commented after the flight, that we were much more comfortable flying than we were driving. The seat cushions in the RV are far superior to the seat cushions in the car. After driving the car, we both got out and had to work the knots out. On the other hand, after the four hour flight, we were able to get out and still feel relaxed!

Make sure you don't get cheap on the interior! I got my seats from Classic Aero, but I'm sure that other companies such as Oregon Aero also do good work.
 
There are so many variables that need to be considered when asking something like this. What are the winds at the altitude that you are flying at? What altitude are you flying? What is your fuel burn? What power setting are you using? What is the weight of your aircraft? So many things. To make assumptions whether an aircraft can make this trip without knowing all the facts is just ridiculous. To give you an example, I have flown my dad's RV6 (6 gallons less capacity than a -7a) from the Charlotte area to south florida on several occasions. Most of the time, I could plan on 8 gallons per hour at 190 mph at 8,000 ft with a possible range to dry tanks (no one would do this) of 855 miles. However, I have also travelled the same route many times at 12,500 ft with a fuel consumption of 7.2 gph at 230 mph (nice tailwind), making a new possible range of 1150 miles, a difference of almost 300 miles (almost the distance from Jacksonville to Miami). Would one consider this? I could fly 1025 miles easily with those conditions, and still have 125 miles left for reserves. That's completely doable, in a -6 no less. The ranges that Van's uses are averages to dry tanks, not reality considering flying conditions.
 
Range in your aircraft

We need to quit looking at miles of range but rather hours of flight time. In twenty years of flying RVs I have yet to have a crosscountry in calm air, it just doesn't happen.. Each knot on the nose cuts your range or visversa,,, classic example,,,, I did Loveland fort Collins KFNL to KEYQ Houston in 4:20 and it took well over 5:30 to come back the next day,,, yes, we were at 17.5 going down with helll of a tailwind. Northbound, I think the semis down on the hiway were making better time than I was.. Ps I did have to stop for fuel on the trip back.
 
The orginal question ...

.... in the first post was about range: do people get Vans numbers or not...

Ofcourse there are TONS of variables, but when it comes to theoretical numbers like range, one assumes atmosphere at std values, zero wind and max GW at T/O.
 
ao.frog said:
.... in the first post was about range: do people get Vans numbers or not...
Click to expand...

To answer his question, he can go fly, set up to whatever power setting he wishes and see what his fuel endurance is. Multiply that by his known airspeed at that setting and he has his answer.
 
Ron Lee said:
To answer his question, he can go fly, set up to whatever power setting he wishes and see what his fuel endurance is. Multiply that by his known airspeed at that setting and he has his answer.
Click to expand...

Yes. I COULD do that except I don't have that configuration. It's OK if people don't want to answer the question, but snark isn't helpful to anybody, and, unfortunately, it's getting harder and harder to find a thread on VAF without it. We should have a goal of respecting each other more and being more helpful. Or, failing that, be silent.

That said, thank you to the people who provided their performance specs.

I think we can move on now.
 
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I think the Van's numbers are generally conservative. Leaning to peak or LOP, electronic ignition can give you further efficiency gains.
I've made several 4 hour+ sectors at gross weight in my RV-8; typically 9-11,000', WOT and LOP total sector fuel burns averaged less than 7 gph for the airborne time and speeds generally 155-160 KTAS depending on weight, altitude, OAT etc. That is about 60% power.
So 900NM+ still air range is entirely achievable.

Maximum range is even greater if you are willing to fly at 100-110 KIAS.

In principal, maximum range barely changes with altitude, but the speed (TAS) at which it is achieved increases with altitude.

Here's an example:

P1000727.jpg
 
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My RV-6 range

Well my RV-6 with O-320 and Constant Speed prop is now over 15-years old and over 2,654.7 hobbs hours, I should be able to give a good answer.

I average 7.3 GPH fuel burn over the course of a year. I always run cruise as lean as possible and do spend a lot of cross-country time lean of peak on a carb. On a good day, (colder than standard) I can get 23" WOT, 160 KTAS, 7.0 GPH at 8,000 MSL. I flight plan at 150 KTAS all the time. I can go faster but I burn more fuel.

I have flown 3 or 4 four-hour legs in the past 15-years. I prefer a 2.5 to 3.5 hour long leg for all the reasons that others have said.

In calm air, I can get 788 sm range with the legal 30-minue reserve. That is 4.5 hours with reserve or just over 5-hours with no reserve. I like a 1-hour reserve as minimum.

Several years ago, I thought my airplane was getting slower. On the way home from Van's homecoming, I ran a little test. I set up my normal cruise at 2,300 RPM, WOT, and 7.0 GPH fuel flow. I had a 154 KTAS and GS. Touching only the mixture, I rotated in in to make the mixture richer. 15-minutes later, I had 164 KTAS and ground speed with a fuel flow of 8.5 GPH. I was still WOT but MAP had gone up 0.1" due to the extra speed coming in through Van's FAB. Turns out that me going slow was just me leaning more aggressively. It take horsepower to go fast and it take fuel to make the horsepower. Not sure who said "There is no such thing as a free lunch." IMHO, if you want to go fast, you are going to burn more fuel.

There is a sweet spot with every engine, prop, and airframe where you will get the best economy. I almost always fly at best economy.
 
MSL or DA

Several who have responded to this thread have not specified whether they are referring to Mean Sea Level or to Density Altitude. For performance numbers, wouldn't Density Altitude be the more relevant variable?
 
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