Propliner Gas Mileage

Willy

Willy

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Decided to take the JBK Boeing 307 Stratoliner on a flight across the Atlantic from Bermuda to the Azores. Just wasn't sure if it had the range to make the flight. Took off from Bermuda and climbed to FL190 (yes, the 307 is pressurized) which is almost as high as the Stratoliner will operate. Settled in at 30" MAP and with a 60kt tailwind and heading east. About 500nm into the flight, my tail wind dropped to 12kts so I throttled back to 25" MAP until time to descend when I dropped it to 20". After a late dusk landing, I was at 9% fuel.

Got 1.09mpg out of the ol' Boeing.....
 
Now calculate the per seat mileage and the old gal is doing quite a bit better than your average family car, and it is doing so with engines that are not really tuned for ultimate efficiency.

Cheers
Stefan
 
Generally the engines of the day used about 0.5lbs/hr/hp developed. Range will depend a lot on the weight of the payload. As a rough check figure about 200 gph at econ cruise of 50%. AFSD will give you your fuel flow and other data.

Cheers: Tom
 
I used a full load of fuel and payload. I was flying this for a few years with the C-75 flight model (more fuel, more payload, no superchargers on the engines and no cabin pressurization). I recently switched it back to the JBK flight model which is a 307B with the two stage superchargers and cabin pressurization, but less payload and fuel.

I've got the RKG fuel status gauge installed on the flight engineers panel which gives fuel flow along with other good to have info.
 
The B-307 Clipper is still my favorite bird to fly. Just need a long, gentle final. She's not very maneuverable as approach speed drops. Otherwise, she's a real lady. Had her up to 20,000 feet. Once. Barely.
 
The 307 Stratoliner is a long time favorite of mine as well going back to the old Vintage Air Works one.

I started this flight out after I switched flight models back at Memphis, flew down through Mississippi landing at every town that had an airport big enough for a commercial flight, turned left at Gulfport, flew across to Jacksonville Florida, then hopped up to Charleston SC. From Charleston, it was out across the water to Bermuda and now I'm in the Azores. I'm figuring on going on to Europe from here. This is one of those flights with no set destination, just see where the nose and the Wright Cyclones take me.
 
I'm in the middle of an adventure with my 307, too, but no passport needed. Started at Boeing Field and headed East in a big clockwise circuit of the U.S. I'm taking a similar appproach, just using NDBs and finding airports that look like they'll take her. Laconia, NH and Martha's Vinyard were challenges for takeoff. Right now, I'm slowly making my way down the East Coast from Portland, ME to Miami.
 
With any PropLiner the fuel load becomes a determining factor as to which runways you can or can't use. More than with modern jets. So for flights that do not stretch the max fuel range if you fuel for the flight at hand many more airports are suddenly in play.
For me that is part of the fun of flying a Propliner and flying them right. Calculate the fuel requirements including reserves and make the flight. At the destination compare fuel remaining to the calculated amount.
If at any point in the flight it looks like I might not have 1 hour in reserve I divert to another airport.
Same procedure I use when flying the real thing.

Cheers
Stefan
 
I do the fuel calculations too quite often and try to err on the side of caution. I remember reading that some propliner pilot having said "The only time I have too much fuel is if I'm on fire". But then he wasn't trying to get a Stratoliner up into the air with a short runway either.

My usual mode though is to start a flight like this with full tanks and then just use it up as I go. Things were a bit dicey in Tupelo MS trying to take off with about 80-90% fuel. Once I get it down to where I start needing to add fuel, I just put in enough to get me to where I'm going with a little extra. My next leg which will be to the other end of the Azores will be like this. Right now the basic idea is to work my way to London.

losttexan, I've done a couple of across the US flights in the 307. Also flew it in our Evita event down to South America. Have you tried Glenn Duncan's panel for it?
 
Willy, I have indeed. I stumbled across Glenn Duncan's panel a couple of years ago. It's great! Made the 307 my favorite plane. I always fly NC19903, partly because I'm still upset that they restored it (twice) beautifully, flew it in one hop to Dulles, where the Smithsonian folks drained all the fluids, never to fly again. So I keep her in the air on my computer. I also love flying the Howard 500. But if I want to just burn holes in the sky, I go to my F8F Bearcat in Howard Pardue's livery. He was a true gentleman to my son.

Watching you and Sunny in this thread, I'm starting to feel a challenge to see if I can calculate fuel myself. Right now, I'm going to go see if I can find Baltimore by dead reckoning as the sun goes down.

LT
 
Just make sure you leave yourself a safety margin. I just flew from Flores to Santa Maria in the Azores. I rough guessed the fuel, then rounded up to 50% to be sure. Landed with about 25%.

View attachment 80601

I've modded the Duncan panel a bit with some odds and ends, mostly from Milton's Spartan.
 
Cool pic. How do you get propliner AI aircraft to show? What a great way to immerse in the old days.

I will err on the side of caution. I sure don't want to dead stick land that big plane!
 
Well guessing fuel is not really planning a flight. Sure there are certain factors that, real or simulated, can't and should not be calculated down to the ounce. We do not want to be one of the "stupid pilots" that end up landing on a freeway in rush hour because they thought they can stretch the fuel better than anyone else.

We had one of those chaps at my home base not too long ago...came in as a glider in his C-172 after a 5 hour flight. Said he'd made the same flight before and had 3 gallons left at Cable airport. That's another 10 minutes of flying time from L67 and can get busy to the point where you need to circle once or twice to find a slot in the arrivals. That sort of reserve after a 5h flight should have him grounded for 3 month....and running out without any holes in the tank or other major mechanical reason for 6.

Almost all of the CC prop liners including our Connies have detailed operating notes and handbooks that allow equally detailed fuel planning. But those are still based on theoretical numbers to some degree and you may not always fly exactly like the book said.
So for an airplane you fly a lot I would make my own notes. After a few flights you have a pretty good idea about your personal gph total. Now plan a flight with your usual weight in cargo and add 2 hours of fuel to your calculated average.
Double check the fuel remaining for the next few flights and see if you usually land with about that reserve. Now you are in the ball park and can if needed reduce to an hour reserve.

In flight however the calculating continues. If you find that it takes longer than you had planned to get to your enroute fixes you need to start doing the math again. At the very least the calculated halfway point should arrive on schedule...if not break out the wiz-wheel and if in doubt land short and buy some more gas.
You meet some interesting people that way...

Cheers
Stefan
 
Sunny, I have the Cal Classics Connie. Fun bird. I'll check the docs for tips when I start learning fuel planning. Thanks for the pointers!

By any chance, have you read WEB Griffin's Corps or Honor Bound books? Interesting descriptions of flying Connies in some of the books of both.
 
You are welcome. Glad you like our Connies...they are almost all covered now ... L-049 through L-1649A. And each is different enough to require a bit of manual study :D
Not sure if I read the books you mentioned, but during development we all read just about every scrap of tri-tail story and tech-spec that we could find.

Cheers
Stefan
 
losttexan said:
Cool pic. How do you get propliner AI aircraft to show? What a great way to immerse in the old days.
Click to expand...

Back when FS9 was young, I took the CalClassic propliner AI and converted some other propliners to AI to go with them and redid the default AI flight plans using them. The TAP Connie in the front is the old FSDezigns L049 using the CalClassic AI L749 flight model. The TWA 307 in the background is the old Vintage Air Works one that flew well enough as AI that it didn't need a specialized flight model. Not as accurate as the CalClassic propliner AI flights, but I had fun doing them although it took me quite a while to run through all the default flight plans and redo them for propliners. I do have some DH 106 Comet 1s flying about doing London - Hong Kong and London - Cape Town, but that's all the jets I have in there.

If I had it to do over, I'd just use the CalClassic AI flightplans.
 
You guys are way beyond me - now. But given enough time, I'll catch up. Right now, I have to see how things are in the Chesapeake Bay.
 
Having listened to you guys, I "borrowed" 200 gallons of 110 avgas from the Navy at Oceana NAS. Afterall, I want to have enough cushion for an extra hour's flying beyond my destination:kilroy:. I mean, they fly jets and turboprops - will they really miss a little avgas?:kilroy:
 
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