The performance of helicopters seems independant of weight and atlitude.
I am unable to pin down a cause.
So far, the characteristic is shared by, but no necesarily limited to:
Huey
Lama
Skycrane
Chinook
H125
Rate of climb at sealevel doesn’t change from minimal weight to max gross weight.
Rate of climb also stays at this high rate at very high altitudes.
eg Chinook, at max takeoff weight is pegged at over 3000fpm and continues climbing to over 40,000 feet with high rate of climb.
The air density/temperature model in FS2020 was accurate and reflected performance expectations from ‘flight manual’ performance graphs accurately.
Changes to heli weight was also accurately reflected in FS2020.
Something is very off in FS2024.
Stu
I was pretty freaked out about this. I did a back-to-back test on MFS24 and MFS20. I used the H145. I tried ascending in a hover at MCP and monitoring RoC and limits. They seemed pretty close up through FL200.
I also tried quickly adding or removing fuel and I find the RoC (again in a hover) was responding as expected.
Some things I didn’t check:
I only tested MFS20 package (maybe MFS24 native opts you into something else)
I only tested live weather
I used fuel weight to test that weight had an impact, I didn’t adjust load stations to ensure they work correctly too.
Does my testing conflict with your assessment, or did I miss the correct scenarios?
Hi
Dave? Not trying to give you a heart attack…
To test this, it is useful to have some figures from the flight manual as a reference.
Hover out of ground effect charts serve this purpose. (HOGE)
At sea level, all heli’s have excess performance at max weight. Therefore, you can use the rate of climb charts for this, as rate of climb is a proxy for excess power.
As you climb, the blades get into thinner air, and for a given set of conditions of density alt and weight, the climb rate drops to zero.
For example the Huey at max TOW, will have a situation of not being able to get out of ground effect (without foreward flight) at just under 9000’.
Another is the CH47 which has a HOGE of 10500’, we got to 40,000 and got bored.
I don’t have the 145 model. A quick google gave me a HOGE of 8995’.
At max TOW, see the difference between FS20 and FS24 in the ability to hover at 8995’. Also make sure that you use ISA sealevel conditions (15C and 2992 subsetting)
Stu
Small update on this one. Stu and I talked offline, we had some confusion around the EFB weight adjustments. Weight station updates are not committed without pressing LOAD IN AIRCRAFT. I think the legacy aircraft is a little less intuitive in the page display and it might help if that button would light up green when there are unsaved changes.
The plot thickens…
Using the Huey (because I can get into and modify the Flight_model.cfg file)
Hover out of ground effect is 9000’ ISA at 9300lbs.
9300lbs including 645lbs fuel = hover out of ground effect.
9300lbs including 1290lbs fuel= 800fpm climb
9300lbs including 10lbs fuel = a low hover only (in ground effect)
9300lbs including 5960lbs passengers and 10lbs fuel = 2500 fpm climb.
All of these are at the same weight.
The composition of the weight matters.
That is, fuel and passengers don’t weigh anything. They appear as numbers, but are not added to the actual weight of the heli for performance.
So our helis are actually performing very similar to FS2020 with the caveat, that you can’t change the mass of the heli by adding fuel, cargo or passengers using either the EFB or the config page.
ie changing the ‘Empty_weight’ changes performance.
changing Fuel load, Cargo or passenger weight does not affect performance.