Huey is underpowered

Hello,

I apologize if this has already been discussed.

Here's my original reddit post which has the video evidence

In the video the real uh-1 achieves a 5ftish hover at a stated 40-45% collective, 20-25 torque, with fuel and 5 souls. (The guy said he only needed about "half" collective to achieve hover)

In game the huey achieves a 5ft ish hover at 60% collective, 28 torque, with fuel and 2 souls.

In the early parts of the video the pilot describes his huey as a Vietnam era model and shows the door gun mounts, so I assume it's the h model that we have. He also identifies his engine, but I didn't think to compare it to dcs... whoops.

(Also, Vrs seems excessive in dcs)

What variant of the Huey is that in the video? Maybe it's a twin engine variant?

He describes the engine in the video. Looks like a single engine but I can go re watch it over lunch break

Edit: you have almost the same computer specs as me! Lol neat

Also what were the flight conditions of your test. Looks pretty cold in the video. Were the temperatures the same?

So he mentions that it was originally a D model upgraded to an H but and he lists some boiler plate H information but we don't know if that H model has the -13 or -703 engine which I think is 400 more horsepower. Yes I saw the list that says -13 but I'm not convinced they didn't just google H model and list the base engine they had versus asking which one. The DCS H has the -13. Also a military helicopter is alot heavier than a civilian one. When they go to civilian service they get stripped of alot of unnecessary equipment like IFF, the second generator, armored seats, etc. So you would need to compare the actual weights of the helicopters. And I've never bothered but people have compared the DCS huey to performance charts and its come up fairly close until you get to high altitudes. Thats not to say it couldn't use some improvement. I'd like to see VRS reduced and more pedal authority added.

Interesting points there that I hadn't considered. My test was on Persian Gulf map, and the video was in Connecticut at what looks to me to be roughly 25-30 degrees. That would make some difference, and so would the weight differences. I can't account for the weight so I can't really argue any further that the huey is underpowered.

As an aside, are the engine and rotor still be worked on? I read a post from earlier this year saying there was a rework coming.

Funny enough: Directly beneath your thread is another thread that complains about too good performance: https://forums.eagle.ru/showthread.php?t=260340 :D

I can't account for the weight so I can't really argue any further that the huey is underpowered.

Using DCS's weight, you can compare the DCS Huey to real performance charts.

IIRC - Torque required to Hover in DCS was pretty accurate (though became inaccurate at higher altitudes), while max Torque available and/or EGT has always been 'off' to a greater or lesser extent when compared to the real charts.

Current EGT's at 0 ft are similar to the RL 6000 ft Max Torque available curve and max torque is limited by EGT.

Once BST correct EGT and Torque, we should be flying to max torque 50 psi (gearbox limitation) upto approx 4000 ft and to 615°C EGT (625°C 30 min max) above that (engine limitation).

For now - EGT is king.

As an aside, are the engine and rotor still be worked on? I read a post from earlier this year saying there was a rework coming.

AFAIK there hasn't been a progress statement since 2018. Priorities change (FA-18C, F-16C, etc., etc.) but it's also possible the rework has grown to include multi-crew, which we know is coming.

Funny enough: Directly beneath your thread is another thread that complains about too good performance :D

Both threads are correct.

The DCS Huey is underpowered and EGT limited at lower altitudes, while the main rotor generates too much lift (or has too little drag) at higher altitudes.

I see, then let's hope the devs will actually still work on engine performance, because I'm not so sure they still do that...

You can see a lot of the speed/torque settings while in flight on this 360 degree video when we hired a UH-1H for a half hour.

This is with ten people on board too, so I would agree with the power gap having seen it first hand.

Starting at 31:49. Watch the airspeed indicator as the aircraft goes under 15 knots and to 0 with a negative vertical speed without hitting VRS and blowing up. I'm not sure in DCS if the excessive VRS is related to the Huey being underpowered or if VRS is a separate issue that needs work, but it needs work at some point (hopefully).

Edit: Re-checking my landing procedures, this doesn't seem too far off from the game. I'm not certain. The video doesn't seem like the huey is about to drop and blow up, but under the same power and landing angle my Huey is a split second away from dropping out of the sky.

... under the same power and landing angle my Huey is a split second away from dropping out of the sky.

The ease at which it is to enter VRS depends on GTW, so you'd need to match your weight.

 

Starting at 31:49. Watch the airspeed indicator as the aircraft goes under 15 knots and to 0 with a negative vertical speed without hitting VRS and blowing up. I'm not sure in DCS if the excessive VRS is related to the Huey being underpowered or if VRS is a separate.

Didnt watch the film but VRS isnt that easy to hit IRL.

From calculation of a weight in middle of empty weight and maximum take off weight you will be quite safe from VRS if keeping the decent speed less than 550 to 700fpm.

The risk starts getting higher at 900 fpm.

The really dangerous area is from above 1000 fpm to 2000 fpm

Heigher weight will need higher descent speed, and lower weight need lover descent speed.

Generally we teach that if you keep descent rate at 300fpm or less you’re safe. In that, theres a good margin for the most helos and weights.

I thought I had made some posts with the calculations, didnt find them though. It might have been in messages.

I’ll get back and post the calculations later.

Its possible to make quite simple calculations about the risk of getting into VRS.

The following formula is supported by a lot of different reserarches. There might be smaller differences about how to do the calculation but the result is very similar between the result of different reseraches.

Vih = Theoreticall downwash = Square root of ( T / ( 2 x p x A)

T = Rotor thrust in Newton ( Lifting force in kg *9.81)

p = Air density, 1.225kg/m^3 on a standard day.

A = Rotor Area in m^2

The risk of getting into VRS is described at a factor of Vih. 0.2-0.3 is safe, 0.4 is also quit safe bur the risk is increasing. 0.5 starts to be dangerous and 0.7-0.9 is most dangerous.

Heres the formula applied on the UH-1H:

https://i.postimg.cc/VNVtvRwZ/VRS.png' alt='VRS.png'>image sharing[/img]

As we can se its quite safe if staying below 600-700 fpm.

 

Starting at 31:49. Watch the airspeed indicator as the aircraft goes under 15 knots and to 0 with a negative vertical speed without hitting VRS and blowing up. I'm not sure in DCS if the excessive VRS is related to the Huey being underpowered or if VRS is a separate issue that needs work, but it needs work at some point (hopefully).

 

Edit: Re-checking my landing procedures, this doesn't seem too far off from the game. I'm not certain. The video doesn't seem like the huey is about to drop and blow up, but under the same power and landing angle my Huey is a split second away from dropping out of the sky.

Just checked that video. Quite normal landing. In most helos the airspeed is unreliable below 30-ish knots because the rotor vind disturbs the flow around the pitot tube. An indicated airspeed = zero doesnt mean the actual speed in the air is zero.

Its a normal descens with a normal descent angle, descent rat is around 500fpm which is some kind of standard. The helo is moving forward until almost above the landing spot. I cannot se the wind but as long as you dont go straight with the wind you wont get VRS in this case.

Normal landings is made to be as safe as possible by being in the middle of the envelope.

So, this video doesnt really have anything to do with VRS or being close to.

Thanks for the info. My point was that the video did show a nice normal landing. But when I do a similar landing in game I'm either hitting Vrs or I'm a split second away from hitting it.

So, subjectively, dcs seems to overdo the vrs aspect of its simulation. But I'm not good enough to test and provide proof.

i think you are confusing the loss of ETL with VRS.

ETL= effective translational lift.

if you don't prepare for the loss of ETL then you will enter VRS because of the increase in rate of descent. and pulling collective wont save you.

pull collective earlier. balance the loss of ETL and you will never enter VRS.

i cannot remember the last time i entered VRS in the huey..

and i do landings like in the video all the time.

That's possible. And I'm not entering Vrs, as I do pull collective earlier. But the aircraft always seems like it's a second away from just falling like a brick. The real one I'm sure is better than this

it may feel like its going to drop like a brick, but it wont :)

if you have the right torque (collective) setting to maintain altitude it wont go anywhere.

it will only drop if you reduce torque. and then only so far as ground effect will increase and stop the descent. so rate of descent decreases as you near the ground. you will never reach the ground without reducing torque further.

as long as you stay within the parameters for rate of descent when in a hover. as shown by gunnars driver.

The performance U that affects all helos( and all aircrafts) makes the helo need a lot less power at 30-40 knots with a minimum at around 60-ish for the Huey and then increase the need for power in higher speeds.

In fact, the power needed for flight at around 60knots is somewhere close to the halv of the hover power.

And, when you are comming in for a landing, and reduce speed, you get energy back which will make you climb again if you dont lower the collective. This means because of the need of lowering the collective and speed reducing, making you enter a high-power-need area of the power curve( airspeed less than the transitional lift speed.)

So when thus happens you need much more power.

What lessens this effect IRL is the ground effect, it reduces the power need significantly. It might be that the ground effect is a bit less in DCS/Huey than in real life, maybe.

I have played around with the huey a bit but not very much. I like it but it is not 100% of a real simulator, even though Ive flown some full flight sims with a lot worse feeling of collective power.

If I fly the huey in DCS as I fly real helos(closing in to 6K hrs) everything is fine and the landings does not feel strange at all. So if you have problem with the collective management, you’d probably see the same thing IRL also.

Just keep training. My guess you dont follow a normal descent angle and speed reduction, and the following need to build power with the collective in time ?