Saving fuel any way they can

[switchflicker]

I seem to remember the DC4 types telling of shutting an engine down on the empty legs to conserve fuel and also to keep the engine times down.

[pelmet]

I know of a successful single engine t/o in yfb on a hs74. No starter so single engine t/o and then a windmill start.

When did that happen. Never heard that story before. Kind of odd to leave a main base to do something like that and you would have to be empty and where would you be going. Doesn't make sense.

[pdw]

Kind of odd to leave a main base to do something like that and you would have to be empty and where would you be going.

"No starter" there can be the starter failing or a weak battery, so in the pinch decides to fire up windmill style as described which warms it up in the circuit and then comes back in to load for the purpose of the mission. Seems like a harmless enough innovation if really stuck

EDIT :
With "hot fueling" is even more plausible to have been done, as the twin could then be nearly 100% empty of payload for it's 'single' take-off.

[valleyboy]

When did that happen. Never heard that story before. Kind of odd to leave a main base to do something like that and you would have to be empty and where would you be going. Doesn't make sense.

It was prior to 7F having 748's and a matter of "geterdone" and get the aeroplane home and to maintenance. The fueler did "hot" refueling in the day. Same guy took a 748 onto the 2otter strip at hall lake and pulled out the fishermen because 7F 2otter did not show up to do the shuttle to hall beach. Different days.

[pelmet]

When did that happen. Never heard that story before. Kind of odd to leave a main base to do something like that and you would have to be empty and where would you be going. Doesn't make sense.

It was prior to 7F having 748's and a matter of "geterdone" and get the aeroplane home and to maintenance. The fueler did "hot" refueling in the day. Same guy took a 748 onto the 2otter strip at hall lake and pulled out the fishermen because 7F 2otter did not show up to do the shuttle to hall beach. Different days.

Thanks,

If it was prior to the 7F days, I have to admit, I am curious as to what carrier it would be. It was so long ago that I am sure no one will be in trouble now. Single engine TO in a 748???? I am skeptical.

[valleyboy]

I am skeptical.

If you knew the captain you wouldn't be.

[The Hammer]

The single engine TO (or one in fx) in the Twotter has been completed successfully many, many times.

They only document the failed attempts. (In YLF CM used too much flap and was airborne before enough rudder control was available.) Getting airborne before VMC has always been the limitation of that bird.

Didn't Wardair get in trouble for shutting down the centre engine on the '27 going eastbound. I think they got caught when TC figured out the engine times were a lot lower on only that engine.

[Meatservo]

Yeah, see they should have shut them all down on a rotating basis. They're so close to the centre it probably wouldn't matter which one was caged.

[pelmet]

Believe it or not, the Twin Otter is one of only a few airplanes where shutting down one engine actually does help your chances. The charts support this hypothesis, in that the loss in cruise speed is actually less than the single engine fuel savings at maximum continuous power, so your specific air range will increase on a single engine. Wouldn't be my first thought, I'll admit.

I was sure that there was something specifically mentioning this in my old manuals but I have not been able to find it. Has anybody else seen this?

[tsgas]

comparing a 4 engine B 747 jet with a DHC 6 is off the wall and contributes SFA to the discussion

[switchflicker]

I'm having a bit of trouble with your 'SFA' comment. Do they not both have engines which burn fuel. And if one of those engines stops burning fuel would the total consumption be less? How much less seems to be the jist of this topic.

[Meatservo]

I tried this once. Trying to avoid a fuel stop, I climbed as high as I could (reasonably) on both engines, to see if I could get any better range at a higher altitude. I concluded that I would run out of fuel before I got home. I shut one down and drifted down to an altitude I could maintain on one, and concluded that I now had enough range to make the distance, plus reserve, but would now be arriving after dark. Since I was on floats, I was forced to make the fuel stop and spend the night there anyway. But if it had been earlier in the day, shutting down an engine would have given me the range to skip the fuel stop.

This seems like a real sketchy way to do business, except in an emergency, but you see I was very motivated NOT to spend a night sleeping in Chateau DeHavilland at the fuel cache. Turns out, I did anyway. Par for the course in those days, but I missed a good date.

[pelmet]

Deleted

[ettw]

I can tell you that I ended up shutting an engine down on the -6 on the west coast of Baffin. I loitered overhead my intended destination while company came up with a rescue plan.

Once everything settled in I did the math and had jags of gas to get back to YFB. The return trip had originally been expected to arrive back in YFB with slightly better than legal VFR reserves. I definitely would have made gas that day going back to YFB single engine.

I had options on the way back and my rescue flight was going to come down from YRB so I offered the option of going back to YFB single engine.

They opted for the rescue.

I had a wonderful prime rib supper and a nap while I waited for my AME.

ETTW

[AuxBatOn]

And if one of those engines stops burning fuel would the total consumption be less? How much less seems to be the jist of this topic.

Not necessarily. You have to increase power on the other engines to compensate for the loss of thrust on one. If you have to increase power above the optimal fuel consumption point (you are likely cruising at that point for range on all your engines), you will burn more gas to get to the same point at the same range.

If you are going for endurance, you are generally able to save some gas....

[pdw]

It's different crunching those numbers on one engine.

[GyvAir]

It's different crunching those numbers on one engine.

I've been told, but haven't crunched the numbers myself, that shutting down one engine on a single gives you optimum fuel consumption rate and maximum fuel endurance, but range is negatively affected.

[tsgas]

some people have taken the k.I.S.S. principal to the extreme. If the subject was lawn mowers than the simple subject of running 1 engine vs 2 engines would be so simple. However airplanes are a lot more complex and aerodynamics come into play. That's maybe why so many people get killed in homebuilts because they considered themselves as experts until their demise.

[pdw]

In a sense like the Wright Brothers ... or better yet like a lot of their competetors back in their day.

[pelmet]

As to the op and the 6. I would be careful before I tried that and more careful about considering the advice of those who said they have. Pilots love to seek the operational exception , and can rationalize anything they do. It might work well at very light weights but not so much if you are heavy.. If fuel is critical that is not the time to start trying to determine all the variables...

I am far away from home but when I get back, I will look up the info in a book I recently read about the 727 called "billion dollar battle" which has detailed info. Plus I will see if I can find any more on single engine ops in the old DHC-6 manuals.

Bottom line, both are cool planes to fly:)))))

Haven't found anything for the DHC-6 yet but I did find something for an aircraft in the same sort of category. Can't copy and paste so you will have to click on this link....bottom of page 207 of a book titled Aircraft Performance By W. Austyn Mair, David L. Birdsall

https://books.google.ca/books?id=7LTPM6 ... ne&f=false

[pelmet]

For what it's worth, this is what WP says about the design criteria in respect of the number of engines:

"The Boeing 727 design was a compromise among United Airlines, American Airlines, and Eastern Air Lines; each of the three had developed requirements for a jet airliner to serve smaller cities with shorter runways and fewer passengers.[3] United Airlines requested a four-engine aircraft for its flights to high-altitude airports, especially its hub at Stapleton International Airport in Denver, Colorado.[3] American Airlines, which was operating the four-engined Boeing 707 and Boeing 720, requested a twin-engined aircraft for efficiency. Eastern Airlines wanted a third engine for its overwater flights to the Caribbean, since at that time twin-engine commercial flights were limited by regulations to routes with 60-minute maximum flying time to an airport (see ETOPS). Eventually, the three airlines agreed on a trijet design for the new aircraft."

On the other hand Flying Magazine wrote in December 1963 that it was because of departure weather restrictions on twins (300ft and 1mile vs 200-1/2 for the then four engine jets) that meant the third engine gave much greater dispatch reliability.

Checked through my book about the design of the 727 called "Billion Dollar Battle". The design had nothing to do with trans-oceanic ops. The Wikipedia article above is pretty much what happened. The Flying magazine reasoning was an added bonus based on my interpretation of the book.

[pelmet]

Btw. I had the interesting experience of flying about 50 hrs with the FE after his little breaker resetting episode on the 72. While it was being investigated internally. Before he was fired. The Captain and FO....verbal dressing down. There is alot more to that story if it is the one you are referring to.
Maybe you are referencing a different incident.

As to your "try that". Challange. Aviation has changed. Some of the things we did 50 years ago when I started flying would solidify the gel coat on the hair of today's generation....which is why we used brylcream.

I think you might be referring to the incident where they were flying to Washington IIRC., and no one fessed up to flipping the breaker back on..
Nothing so dramatic in the one I was referring to, but a very similar scenario...loss of control and damage to the plane.

The incident I was referring to was TWA 841 was enroute to Minneapolis from JFK and went out of control.

This is an incident forum. Why don't you just tell us what information you have and on what incident. That is the sort of thing that can save lives, which is what this forum is all about. Seeing as you metioned it in response to my statement of extending flaps in cruise, it sounds like your FE coworker had an interesting experience. Looks like someone decided to try the Hoot Gibson maneuver in Canada(probably a cargo carrier) and had the FDR/FDIS/equivalent catch them out on it. Probably tried it just for fun. Hmmm which cargo carrier(all just guess of course).

Based on information gleaned from "various sources", I am pleased to have come to the conclusion that no Canadian carrier that I am aware of has tried something like this. An American carrier owned by a race car driver apparently had "everyone" doing interesting things though, as I was able to piece together.

Not sure why people would do this sort of thing after the big incident at TWA, though.

Closing one engine enroute isn't going gain anything either.