Endurance of KA-50?

[Speed]

I thought that the endurance (how long the engines can run) was unchanged regardless of whether you are flying or just sitting on a pad. However, I just made a mission where I just sit on the runway running off of fuel tanks and a full load of gas, and it took an hour and forty minutes for my external tanks to run dry. I could have sworn they ran dry in just ~45 minutes of normal flying the other day. Is it not true then? Is the endurance changed when you are in the air? Either way, what is a good estimate of the endurance of a fully fueled (100%) Ka-50 with and without fuel tanks?

 

Why wouldn't the in-air endurance of the KA-50 be equal to the endurance of it just sitting on the runway if the same throttle setting is used on both?

 

One final edit, with full fuel, fuel tanks, and just sitting on the runway with a fully started helo I got an endurance of 4:15, 1:40 of which was burning off of fuel tanks, so that would be 2:35 on internal fuel alone. This seems to be about double what I have experienced in the air. I guess the throttle doesn't govern what the fuel flow rate is?

Edited July 13, 2010 by Speed

[AlphaOneSix]

The throttle just tells the fuel control what setting to be in. In AUTO, it means that the fuel control needs to meter the fuel to the engines in a way that keeps the rotor rpm at the nominal setting. ON the ground, that's easy, you are at nearly flat pitch, the blades are easy to spin. While flying, however, you have to add a lot of pitch to the blades, so they want to slow down, so the fuel controls toss more fuel into the engines to speed them up which in turn keeps the rotor from slowing down too much. Your fuel burn rate will only stay unchanged if your EGT stays unchanged. As soon as your EGT rises, it means you're burning more fuel.

[SDeath]

I thought that the endurance (how long the engines can run) was unchanged regardless of whether you are flying or just sitting on a pad. However, I just made a mission where I just sit on the runway running off of fuel tanks and a full load of gas, and it took an hour and forty minutes for my external tanks to run dry. I could have sworn they ran dry in just ~45 minutes of normal flying the other day. Is it not true then? Is the endurance changed when you are in the air? Either way, what is a good estimate of the endurance of a fully fueled (100%) Ka-50 with and without fuel tanks?

 

Why wouldn't the in-air endurance of the KA-50 be equal to the endurance of it just sitting on the runway if the same throttle setting is used on both?

 

One final edit, with full fuel, fuel tanks, and just sitting on the runway with a fully started helo I got an endurance of 4:15, 1:40 of which was burning off of fuel tanks, so that would be 2:35 on internal fuel alone. This seems to be about double what I have experienced in the air. I guess the throttle doesn't govern what the fuel flow rate is?

 

Rotors running fuel on the ground is always less than flying fuel flow.

The engines need more power to keep the total weight in the air.

When you are sitting on the ground the engines need only a small amount of power to keep the rotors running.

For example a 200 hp engine can turn the rotors, but you need 2200 hp per engine to get the a/c in the air. So to get to this amount of power fuel consumption increases.

[Speed]

Rotors running fuel on the ground is always less than flying fuel flow.

The engines need more power to keep the total weight in the air.

When you are sitting on the ground the engines need only a small amount of power to keep the rotors running.

For example a 200 hp engine can turn the rotors, but you need 2200 hp per engine to get the a/c in the air. So to get to this amount of power fuel consumption increases.

 

Right, that's what I figured was going on after my tests came out with such a long endurance, but can anyone give a good estimate as to what the KA-50's endurance mgiht be flying over, say, level terrain at various speeds? I suppose this is in the manual somewhere, but I'd like to hear it from someone who has tested it for himself.

[SDeath]

Sorry not for the Ka-50, I could tell you for the S-61, S-76, EC-155 and AW-139. Because I work with them every day. But that wouldn't be of much help now would it. =-)

[GGTharos]

Why not measure it yourself?

 

Start a flight for approximately 1 minute, and record fuel flow.

 

Then change one of airspeed, altitude (MSL) or gross weight and try again.

That way you'll eventually build up a chart.

 

You can calculate endurance by just using how much fuel was used in that one minute - multiply by 60, and you'll know how much is used in one hour.

 

Your most efficient cruising speed should be 130IAS (it is also the best climbing speed)

 

Right, that's what I figured was going on after my tests came out with such a long endurance, but can anyone give a good estimate as to what the KA-50's endurance mgiht be flying over, say, level terrain at various speeds? I suppose this is in the manual somewhere, but I'd like to hear it from someone who has tested it for himself.

[flanker0ne]

Find some very useful information to share with you, hardcore helicopter pilot simmer as I am.

 

 

The graphic on the Black Shark 2 manual is not very readable so is not helpful enough to become a flight tool.

But the data reported on it are accurate, as the original russian TB3-117VMA document show.

Edited February 25, 2013 by flanker0ne

[EtherealN]

Why not measure it yourself?

 

Start a flight for approximately 1 minute, and record fuel flow.

 

Then change one of airspeed, altitude (MSL) or gross weight and try again.

That way you'll eventually build up a chart.

 

You can calculate endurance by just using how much fuel was used in that one minute - multiply by 60, and you'll know how much is used in one hour.

 

Your most efficient cruising speed should be 130IAS (it is also the best climbing speed)

 

Or do a Panzertard... :D

[JaBoG32_Herby]

Rough numbers are about 550 kg/h at a cruising speed around 150 km/h as a minimum fuel consumption, giving you an endurance of about 3 h without external tanks and around 850 kg/h in hoverflight, both at sealevel and 15 °C with a usual weaponload. Fuelflow in hover equals a cruisespeed of around 220 km/h, whereas fuelconsumption at speeds less then this 220 km/h is lower than 850 kg/h and as the grafic above shows goes up to around 1000 kg/h at higher speeds or higher power demand. For my playtime estimates I know that I usualy have a minimum of about two hours missiontime based on the numbers given.

 

Regards

 

Herby

[JG14_Smil]

Or do a Panzertard... :D

 

My sister once did a Panzertard. She had to go see a Doctor and get a shot.

 

I do miss him, though.

 

Fuel flow/consumtion would not be the first thing in BS that was not correct...

Edited February 25, 2013 by JG14_Smil

[EtherealN]

"Doing a Panzertard" in this case entails taking a mission on the 104th server where striker zones are widely segregated, strapping some fuel tanks onto the Shark, and then spend something like 3 hours one-way flying to the enemy base (with me and GG in F-15s doing air cover) and surprise the heck out of people. :D

 

Did that a couple times, it was hilarious. That man has patience. :D

[RIPTIDE]

Why not measure it yourself?

 

Start a flight for approximately 1 minute, and record fuel flow.

 

Then change one of airspeed, altitude (MSL) or gross weight and try again.

That way you'll eventually build up a chart.

 

You can calculate endurance by just using how much fuel was used in that one minute - multiply by 60, and you'll know how much is used in one hour.

 

Your most efficient cruising speed should be 130IAS (it is also the best climbing speed)

I remember years ago Tyger said something like the External fuel tanks also will last about an hour at 260km/h (ergo, 260km range then.) Can't remember exact figures but it was about that.

[Bushmanni]

Hey Speed, maybe you can give some help with this:

 

http://forums.eagle.ru/showthread.php?t=93217&highlight=cruise+charts

[JG14_Smil]

sorry to go OT. I remember PT's long flights.

 

I would be happy to help gather data if needed.

[104th_Cobra]

"Doing a Panzertard" in this case entails taking a mission on the 104th server where striker zones are widely segregated, strapping some fuel tanks onto the Shark, and then spend something like 3 hours one-way flying to the enemy base (with me and GG in F-15s doing air cover) and surprise the heck out of people. :D

 

Did that a couple times, it was hilarious. That man has patience. :D

 

Did that once. Introduce new route on ABRIS and PVI-800, load Vikhrs and two fuel tanks: on route from Krymsk or Krasnodar (I don't remenber exactly), thru the mountains to Sochi. Only to have a ping timeout or game crash after almost one and half hour from take off :D

[HugePanic]

here is a chart from a Bo-105 helicopter --> classical configuration with tail-rotor.

 

it shows needed power over speed and indicated the most important factors:

Tail-rotor, induced drag, parasitic-drag, profile+compression, "other" losses

(right side, bottom to top)

 

The power-levels are:

Start-Power, max. endurance power, and endurance (route??) power

(from top to bottom)

 

As you can see, at about 120km/h (75mph) the required power is minimal, and should give the longest flight time for this helicopter....

[flanker0ne]

I'm experiencing some discrepancy between the data of temperature and RPM of the turbine (N1) with those shown in the table posted on the previous page (and in the BS2 Manual), as if the values ​​were staggered or moved.

 

Example, by matching the indexes of the engines in the EPR gauge with the Cruise, the readings of T_3 and N_1 are much closer to the higher Max Continuous.

Edited February 26, 2013 by flanker0ne

[flanker0ne]

That is what I mean with discrepancy:

 

1 st Cruise: EGT 815°C correspond to N_gg 93,9 +- 0,5 %.

Ok but the EPR index should be at K

 

Max Continous: EGT 845°C correspond to N_gg 95,0 +- 0,5 %.

Ok but the EPR index should be at H

 

Take Off: EGT 920°C correspond to N_gg 97,7 +- 0,5 %.

Ok but the EPR index should be at B, almost

[Griffin]

Just checking, did you have anti-ice on?

[flanker0ne]

No Anti Ice OFF

ISA condition: 15°C 760mmHg, almost sea level no wind

[Griffin]

I'm wondering if the table and the EGT gauge show a different thing. See the table shows the T3 temperature which is in fact turbine entry temperature. Now the question is, does the EGT gauge measure the T3 or the "true" EGT (after turbines)?

 

EDIT: Also the table assumes that the H=0, V=0 which is altitide and speed zero?

Edited February 26, 2013 by Griffin

[flanker0ne]

Температуры газов перед турбиной = Gas Temperature before Turbine

[Griffin]

The Russian flight manual states it in better detail that the gauge is in fact T3 = gas temperature before turbine. You can also disregard what I was wondering. The difference between T3 and "true" EGT would be opposite of your findings.

[flanker0ne]

:smilewink:

[Griffin]

Would be nice to have someone like AlphaSixOne comment on this.