scandinavian13

[08SEP16] Flight Planning Tools

19 posts in this topic

In case some of you didn't know, there is actually a performance profile for PFPX included in the documentation folder of the DC-6. If you need help on where to put the files, look to the Intro Manual in the same folder.

 

All the same, some prefer to use the free - and very well put together - SimBrief site to plan their flights. Have a look at the aircraft list near the bottom. They now have a DC-6 profile available for your flight planning needs.

2

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

I was just looking at SimBrief the other day in the hopes that they would include the DC-6 profile. Thanks so much for the heads up!

0

Share this post


Link to post
Share on other sites

I really like SimBrief, however they seem to always put my cruise at FL120, no matter how long/short the flight...

 

When do you guys stay down low, when do you climb higher?

0

Share this post


Link to post
Share on other sites

Stefan,

 

The DC-6 is a prop, not a jet. While it has superchargers, it doesn't get anywhere near the compression that a jet does, so efficiency is actually lost at higher altitudes. It is most efficient from about 8000 to about 12000 feet. You can see this reflected in the performance tables if you do a little math on the fuel numbers.

 

It does possess the capability to go much higher than that, but in the case of a piston engine, capability does not mean efficiency. Cases where you'll climb higher: wind is more favorable, terrain, low weather (clouds below you containing ice, etc.).

0

Share this post


Link to post
Share on other sites

This topic was of interest to me during testing, because the DC-6 performance is not analogous to the turbocharged C-414 that I've flown for a decade.  The difference supercharging vs turbocharging.  The supercharger is engine driven and has conventional throttle to control manifold pressure.  It takes a lot of air to feed those big radials and I don't think turbochargers were a thing yet.  However, with turbocharging the waste gas (exhaust) drives the air pump and manifold pressure is controlled by a waste gate, close the gate and MP rises. The waste gate dumps the air from the pump overboard that is not required to sustain the desired MP.  By the way, there is plenty of air to also pressurize the aircraft. The supercharged engine looses MP with altitude, and you continue to open throttle to maintain a setting until 'critical altitude' whereas the turbocharger automatically adjusts the waste gate to hold MP all the way to aircraft ceiling.  This allows the turbocharged engine to perform the same a sea level as it does at FL250 and since the air is thinner the TAS increases significantly.  Set power at 75% and I'd get about 160 KTAS at 8000 ft but go up to FL230 and the same power and fuel I'd get 200 KTAS.  The DC-6 cannot take advantage of this TAS increase because the engines feel the effect of altitude.

0

Share this post


Link to post
Share on other sites

I remember years ago in DC-6 Basic First Officer new hire school our instructor on power plants drove the point home quite well as to the difference between the DC-6 and the DC-7.

"Well, the best way to tell the difference between a DC-6 and a DC-7 when they're taxiing on the ground at a distance is if the plane is being followed by fire trucks it's  probably a DC-7."

The DC-7 had what was, at least at that time, the most powerful and complicated propeller engine in history. It had an engine power optimizer lacking on the DC-6 which allowed it to operate economically at much higher altitudes. The engine section that permitted this increase in altitude was called the "Power Recovery Turbine or "PRT".

It had the unfortunate habit of "melting down" and catching fire with not uncommon regularity...............very expensive  to repair!

This is one of the reasons that the DC-6 flew for three or four years longer with my airline than the DC-7.

0

Share this post


Link to post
Share on other sites

Would someone mind taking a look at the PFPX profiles that were provided with the v4 release? The weights look off to me. I can't seem to plan a flight from KLAX to PHNL without needing a lot more fuel than it says the DC-6 can carry, even with zero payload. Also MTOW looks low to me too. Thanks

0

Share this post


Link to post
Share on other sites
On 18.5.2017 at 10:32 PM, Quink said:

I remember years ago in DC-6 Basic First Officer new hire school our instructor on power plants drove the point home quite well as to the difference between the DC-6 and the DC-7.

"Well, the best way to tell the difference between a DC-6 and a DC-7 when they're taxiing on the ground at a distance is if the plane is being followed by fire trucks it's  probably a DC-7."

The DC-7 had what was, at least at that time, the most powerful and complicated propeller engine in history. It had an engine power optimizer lacking on the DC-6 which allowed it to operate economically at much higher altitudes. The engine section that permitted this increase in altitude was called the "Power Recovery Turbine or "PRT".

It had the unfortunate habit of "melting down" and catching fire with not uncommon regularity...............very expensive  to repair!

This is one of the reasons that the DC-6 flew for three or four years longer with my airline than the DC-7.

I have heard stories about how people living below the final approach path at Oslo knew the arrival times for the SAS DC-7's by heart so they knew when to collect their clothes hanging outside so they wouldn't get oil stains from the DC-7 engines. :laugh:

0

Share this post


Link to post
Share on other sites
2 hours ago, MattS said:

Would someone mind taking a look at the PFPX profiles that were provided with the v4 release? The weights look off to me. I can't seem to plan a flight from KLAX to PHNL without needing a lot more fuel than it says the DC-6 can carry, even with zero payload. Also MTOW looks low to me too. Thanks

What are you comparing them to, and where are you looking?

0

Share this post


Link to post
Share on other sites
4 hours ago, scandinavian13 said:

What are you comparing them to, and where are you looking?

My bad, I guess I was still in a sleep haze this morning. 

I guess I just have to experiment with power settings, etc a little bit more. I'm still not sure why PFPX says I won't make Hawaii from the mainland. I thought the DC-6 used to do that.

0

Share this post


Link to post
Share on other sites
18 minutes ago, MattS said:

I thought the DC-6 used to do that.

If you are thinking of "The High and The Mighty," that was a DC-7.  Let's see, back of envelope distance KSFO-PHNL 2100 nm, avg cruise about 500 lbs/hr/eng so using 2000 lbs/hr and allow 200 kt GS due to some headwind we need 10.5 hrs and 21,000 lbs fuel.  Yeah, that is more than the DC6 can carry and you haven't added reserves, alternate and ETP allowance yet.  Don't need a fancy PFPX to tell you that, and when it does tell you  that you might want to believe it.

0

Share this post


Link to post
Share on other sites
30 minutes ago, downscc said:

If you are thinking of "The High and The Mighty," that was a DC-7.  Let's see, back of envelope distance KSFO-PHNL 2100 nm, avg cruise about 500 lbs/hr/eng so using 2000 lbs/hr and allow 200 kt GS due to some headwind we need 10.5 hrs and 21,000 lbs fuel.  Yeah, that is more than the DC6 can carry and you haven't added reserves, alternate and ETP allowance yet.  Don't need a fancy PFPX to tell you that, and when it does tell you  that you might want to believe it.

https://airandspace.si.edu/exhibitions/hawaii-by-air/online/post-war-travel/speed-and-comfort.cfm

https://en.m.wikipedia.org/wiki/Douglas_DC-6

I hate to quote Wikipedia, but there are other examples of the DC-6 flying from the mainland to Hawaii with regular passenger service. 

I am interested to hear how that was done. 

0

Share this post


Link to post
Share on other sites

The high and the mighty was a DC-4.

I see in the manual they mention a 10-tank setup and a 8-tank setup. I guess you get a few more NM with the 10-tanks.

0

Share this post


Link to post
Share on other sites
18 minutes ago, F16_Driver said:

The high and the mighty was a DC-4.

I see in the manual they mention a 10-tank setup and a 8-tank setup. I guess you get a few more NM with the 10-tanks.

I would image that explains it. Thanks. 

0

Share this post


Link to post
Share on other sites

Yup, I was wrong..., again.  I did forget about the 10 tank option too.

0

Share this post


Link to post
Share on other sites