DHC-4 performance

[qunow]

Per http://www.c-7acaribou.com/history/images/caribou_brochure_web.pdf

At 170kt TAS, the speed set in AWS, the aircraft should fly about 0.15nm per lb fuel, which mean 6.667lb=3.024kg fuel consumed per nm cruise, which should equal to about 514 kg/h fuel consumption, under the condition of "FLAPS & GEAR UP, STANDARD DAY (ISA), WEIGHT 28,500 LB, ALTITUDE 7500 FT". Compaed to 370 in game. At 160kt the aircraft fuel consumption will probably be closer to the value in game but that's 160.
And again at 160kt TAS, using VFR, max range of the aircraft should be up to 1210nm. The range at 30 passenger payload should be about 750nm.

[Talentz]

Per http://www.c-7acaribou.com/history/images/caribou_brochure_web.pdf

At 170kt TAS, the speed set in AWS, the aircraft should fly about 0.15nm per lb fuel, which mean 6.667lb=3.024kg fuel consumed per nm cruise, which should equal to about 514 kg/h fuel consumption, under the condition of "FLAPS & GEAR UP, STANDARD DAY (ISA), WEIGHT 28,500 LB, ALTITUDE 7500 FT". Compaed to 370 in game. At 160kt the aircraft fuel consumption will probably be closer to the value in game but that's 160.
And again at 160kt TAS, using VFR, max range of the aircraft should be up to 1210nm. The range at 30 passenger payload should be about 750nm.

Qunow! 

Firstly, that is a nice document. It has some good info.

However, I must pick apart some things about your OP based on reading through that doc.

And again at 160kt TAS, using VFR, max range of the aircraft should be up to 1210nm. The range at 30 passenger payload should be about 750nm

Yes, the max range of the aircraft flying at MTOW would be 1210 in "zero wind" which basically means still air. Such ideal conditions never exist. Plus, 30 pax in AWS weight in at 98kg per pax (w/bags - this example was given in the manual under Cargo transportation) So, 98kg x 30 = 2940 kg. Max Payload is 3910kg as per the document. That leaves 970kg of fuel (no cargo) to load. Lets look at these numbers:

DHC-4 max fuel: 829 us gal/4974 lbs/2256kg

So max Pax (2940 kg) + max loadable fuel (970kg of 2256 kg) = not 750nm... not enough fuel. Even more so if you take your 514 kg/h fuel consumption into consideration.

Thus, you can say that the listed 1210nm "still air" range is ferry range. Since the aircraft can't take more then 2256kg of fuel.

But you know whats funny? The actual payload/range data is listed in the document!!

PAYLOAD — RANGE
(VFR Utility Version) at 28,500 lb gross weight.
Payload for:
200nm 371 km 8620 lb/3910 kg
400nm 741 km 7774 lb/3526 kg
600nm 1112 km 6916 lb/ 3137 kg
950nm 1760 km 5417 lb/2457 kg

(Cruise  at  7500  ft  at  2  x  725  BHP,  fuel  for  take-off,  climb,  cruise,  descent,  landing  &  45  min. 
reserve)

So, yes some of the data may be a bit off. The DHC-4 appears to have better longer range performance. Since Max fuel is 2256kg, it can reach its max range with some payload left over before falling out of the sky around 950nm or so. The payload-range chart shows this. However, It also assumes a cruise speed of 157knt.

Now, lets bring this all together:

DHC-4 Caribou

Summary: The de Havilland Canada DHC-4 Caribou is a Canadian-designed and produced specialized commuter and cargo aircraft with short takeoff and landing (STOL) capability.

Weights:
MTOW: 12,928 kg
OEW: 7997 kg
MZFW: n/a
MLW: 12,928 kg (??)

Speed:
Max: 188knts
Max Cruise: 170knts
EcoCruise: 157knts

Engines:
2x PW 2000 7M2 (1450 BHP)

Range:
w/ Max payload: 200nm
w/ 3526 kg: 400nm
w/ 3137 kg: 600nm
w/ 2457 kg: 950nm
Max still air (ferry): 1210nm

Rwy Requirement:
Takeoff: 361m
Landing: 376m

Cargo space:
Cabin space total: 32.5 cu ft
Cargo belly: None

Seating:
Max: 30
Std: 26

DHC-4F Cargo Caribou

Summary: The de Havilland Canada DHC-4 Caribou is a Canadian-designed and produced specialized commuter and cargo aircraft with short takeoff and landing (STOL) capability. The DHC-4F is the Cargo only variant.

All data is same as Pax version DHC-4

Cargo space:
32.5 cu ft


Talentz

Source(s):
qunow's http://www.c-7acaribou.com/history/images/caribou_brochure_web.pdf
https://www.flightglobal.com/FlightPDFArchive/1958/1958-1-%20-%200478.PDF

[qunow]

Thanks for your analysis,

Qunow! 

Firstly, that is a nice document. It has some good info.

However, I must pick apart some things about your OP based on reading through that doc.
Yes, the max range of the aircraft flying at MTOW would be 1210 in "zero wind" which basically means still air. Such ideal conditions never exist.

Note that, while AWS do take account wind when calculating flight time, the payload restriction applied onto flights are often the same in both ways, meaning wind is not taken into account for payload range calculation.

Plus, 30 pax in AWS weight in at 98kg per pax (w/bags - this example was given in the manual under Cargo transportation) So, 98kg x 30 = 2940 kg.

The assumption I saw in AWS's chart for 30 pax is 2805 kg.

Max Payload is 3910kg as per the document. That leaves 970kg of fuel (no cargo) to load. Lets look at these numbers: DHC-4 max fuel: 829 us gal/4974 lbs/2256kg

Max payload is max payload. Not fuel. The total allowable payload plus fuel, from data listed, should be MTOW-OEW, =4589kg. The difference between the two would be the difference between MTOW and MLW

So max Pax (2940 kg) + max loadable fuel (970kg of 2256 kg) = not 750nm... not enough fuel. Even more so if you take your 514 kg/h fuel consumption into consideration.

514kg/h is the fuel consumption at 170kt. , with about 2× 900 bhp engine power. Using engine power output of 2× 725bhp, which is the setting used for both the payload range chart and the data, the fuel consumption will be noticably less than this.

Thus, you can say that the listed 1210nm "still air" range is ferry range. Since the aircraft can't take more then 2256kg of fuel.

This is indeed my mistakes, not noticing that the range for 1210nm was listed without referencing to reserve at VFR, which probably mean the range is the ferry range without reserve, contrary to what I claimed in OP. This also explained why the payload range chart does not go as far as 1210nm, as the chart is made with reserves considered.

But you know whats funny? The actual payload/range data is listed in the document!!

So, yes some of the data may be a bit off. The DHC-4 appears to have better longer range performance. Since Max fuel is 2256kg, it can reach its max range with some payload left over before falling out of the sky around 950nm or so. The payload-range chart shows this. However, It also assumes a cruise speed of 157knt.

The speed and power asumption is the same both in this set of data and in the payload range chart.

Now, lets bring this all together:

DHC-4 Caribou

Summary: The de Havilland Canada DHC-4 Caribou is a Canadian-designed and produced specialized commuter and cargo aircraft with short takeoff and landing (STOL) capability.

Weights:
MTOW: 12,928 kg
OEW: 7997 kg
MZFW: n/a
MLW: 12,928 kg (??)

MLW should probably be OEW + max payload + reserve fiel
And the document actually listed 8337kg for OEW for VFR. OEW also count the weight of crew and equipment

Speed:
Max: 188knts
Max Cruise: 170knts
EcoCruise: 157knts

Engines:
2x PW 2000 7M2 (1450 BHP)

Range:
w/ Max payload: 200nm
w/ 3526 kg: 400nm
w/ 3137 kg: 600nm
w/ 2457 kg: 950nm
Max still air (ferry): 1210nm

Rwy Requirement:
Takeoff: 361m
Landing: 376m

Here I am slightly confused by the document. The document said "While the Caribou is a STOL aircraft designed to operate from VERY SHORT unpaved runways, 1200 feet (365 metres) in length, it is capable of carrying greater payloads from ordinary runways, 2500 feet (765 metres) or more in length." despite the previous data for 361m takeoff was at MTOW, and that 361m figures already include ground roll plus overpass obstacle after takeoff.

Cargo space:
Cabin space total: 32.5 cu ft
Cargo belly: None

Seating:
Max: 30
Std: 26

From my previous DC-3 thread, seems like standard seating of aircraft is actually auto determined by system based on max seating and cabin floor space, not to be manually inputted.

DHC-4F Cargo Caribou

Summary: The de Havilland Canada DHC-4 Caribou is a Canadian-designed and produced specialized commuter and cargo aircraft with short takeoff and landing (STOL) capability. The DHC-4F is the Cargo only variant.

All data is same as Pax version DHC-4

Cargo space:
32.5 cu ft

OEW should be ~270lb less than passenger version due to lack of seats. The max payload should be increased by same number


Talentz

Source(s):
qunow's http://www.c-7acaribou.com/history/images/caribou_brochure_web.pdf
https://www.flightglobal.com/FlightPDFArchive/1958/1958-1-%20-%200478.PDF
[/quote]

[freshmore]

Look at the payload range graph on page 23. Doesn't the IFR variant at 2900kg payload have a range of 360nm. The max payload in AWS looks to be the same as the max payload for the VFR variant yet the IFR variant seems to have been used for range as the VFR 700nm range at 2900kg payload.

So I stand to be corrected on this, but doesn't it seem that the data in AWS is to some extent a hybrid of both variants. Also isn't it worth nothing the Payload range in AWS drops off to zero payload at max range yet the payload at max range in the document is about 2100kg for the IFR for a range of just under 800nm.

[qunow]

Look at the payload range graph on page 23. Doesn't the IFR variant at 2900kg payload have a range of 360nm. The max payload in AWS looks to be the same as the max payload for the VFR variant yet the IFR variant seems to have been used for range as the VFR 700nm range at 2900kg payload.

So I stand to be corrected on this, but doesn't it seem that the data in AWS is to some extent a hybrid of both variants. Also isn't it worth nothing the Payload range in AWS drops off to zero payload at max range yet the payload at max range in the document is about 2100kg for the IFR for a range of just under 800nm.

IFR/VFR are not variants. They are different flight rule. The aircraft is the same, just that they are flown differently. The main reason why the payload range chart look different, is that VFR only require 45 minutes reserve fuel, while IFR require at least reserve fuel enough to do 200nm and then additionally a 45 minites holding, which translate to a total of almost 2 hours reserve. From p.22 you can also see that operators using IFR in real life typically put more equipment on board and the radio is heavier but all summed up it is only about 300kg.

[freshmore]

I understand all that. However 300kg more weight in respect to an payload of just under 4000kg is significant.

However my point was,

2891kg translates to 330 nm AWS - The page 23 graph shows 2900kg getting you 360nm in IFR configuration. It's a bit out but seems to show a bit of a match. More than the VFR which seems to give about 720nm/2900kg.
The max payload in AWS is 3965kg and for the VFR configuration 3900kg is the max on the graph, the IFR is 3500kg or so. In this case the VFR provides a better match.

So doesn't this suggest that the range/payload in AWS might be a hybrid of both data sets, furthermore, AWS carries 0kg payload at 685nm and the graph suggest the IFR at least can carry about 2100kg 800nm. The max range of the VFR is 1210nm, presumably that is full fuel zero payload.

Therefore, shouldn't we be taking the data from one variant/configuraton.
If it was the VFR:
Max payload of 3900kg up to 200nm.
From there is drops linearly to 950nm/2400kg and from there is drops to 0kg and 1210nm.

If it was IFR:
Max Payload 3500kg.
120nm/3500kg dropping linearly 200nm/3200-3300kg and from there drops to 790nm/2100kg and then to something like <1210nm/0kg.

The IFR variant matches the range seen in game better and the VFR matches the Max Payload better. In the game payload drops off to zero way to fast it would seem. I would suggest the conclusion is the data set is taken from both as well as dropping off to zero payload too early. I'll leave the fuel stuff up to you and Talentz.