The Governor / Overspeed Governor might not yet work as it should

[buedi]

Hi everyone,

 

I´m not a real pilot, so my knowledge comes from other Sims and reading procedures and Aircraft manuals.

I flew the Dodosim 206 in FSX a lot and there the governor and the torque meter play a huge role in the startup procedure. I also fly the DCS: UH-1H a lot and I was not sure until yesterday if the Overspeed Governor is just working differently on the Huey.

 

But yesterday I came across a UH1-H manual and it seems that the Governor should work like I am used to it also from the Dodosim 206.

 

In the Huey manual they describe the Governor also as the "Overspeed Governor" and describe its functionality exactly the same as it´s for the Dodosim (Bell) 206.

 

I´ll try to describe how, according to all what I´ve read, it should work and how it works for me in the DCS Huey.

 

First, during Startup the Governor should be activated.

After you get the Turbine up and running and it´s stable in idle, the runup includes to slowly increase the throttle which in turn rises the RPM of the Turbine and the Rotor blades. The RPM increases while you advance the throttle (yes, with the governor on) until you reach the set RPM (6.600 is the default I think) where then the governor gets active and prevents overspeed, even if you increase the throttle more and would reach for example 6.900 otherwise. In fact it´s part of the procedure to advance the throttle to full open, so the governor has more room to act in both directions. So the only thing the Governor does is preventing overspeed. With the Governor switch on the collective you can then make small adjustments to the RPM if desired.

 

In the DCS Huey, when the governor is active, nothing happens when you advance the throttle slowly and when you reach max throttle, the engine spools up to 6.600 pretty fast. So the throttle is more like a on/off switch when the Governor is on in the DCS Huey and does not allow you to slowly spool up the engine. This confused me when I first flew the DCS because I expected it to rip apart the transmission by spooling up that fast.

 

This might be a minor detail, but there´s another point. Something I´m not sure if it is valid for the Huey also. But in the 206 if you spool up the engine too fast, torque rises too much and it can do serious damage to the transmission. In the 206 you HAVE to slowly and steadily rise the throttle to prevent spikes in the torque until you reach the right RPM. Also when quickly rising collective you can get spikes in the Torque in your transmission which can lead to malfunctions. Now, I don´t know if the transmission in the Huey is much more robust than in an 206 or if this is just not modelled.

 

Flying the 206 in FSX is a little bit more of a challenge here, including the Startup procedure, which is also more fun at least for me because it feels more real (that´s why I play sims) :-)

 

As I said before, until yesterday I was not sure that the Overspeed Governor is working the same as I thought it should. But it seems to me that it is not correctly modeled yet. Can someone confirm this?

Also it would be great to have some input from people who know how the real Huey works if you don´t really have to pay attention to the Torque meter when spooling up the engine. Currently in the Huey you only have to pay attention to the Torque meter during flight that you do not rise the collective too much. But it feels like it does not matter how quick you rise it, there are no torque spikes. It would be very interesting to hear what others know about this topic.

 

 

 

Edit:

For reference from the Manual I read yesterday:

TM 55-1520-210-10

Operator´s Manual

Army Model

UH1H/V Helicopters

HQ DoA

15th February 1988

c. Power Controls (Throttles). Rotating the pilot or copilot twist grip-type throttle (fig 2-5) to the full open position allows the overspeed governor to maintain a constant rpm. Rotating the throttle towards the closed position will cause the rpm to be manually selected instead of automatically selected by the overspeed governor. Rotating the throttle to the fully closed position shuts off the fuel.[...]

[...]

d. Governot switch. The GOV switch is located on the ENGINE control panel (fig 2-6). AUTO position permits the overspeed governor to autmatically control the engine rpm with the throttle in the full open position. The EMER position permits the pilot or copilot to manually control the rpm. Because automatic acceleration, deceleration and overspeed control are not provided with the GOV switch in the EMER position, control movements must be smooth to prevent compressor stall, overspeed, over-temperature, or engine failure.[...]

Edited January 26, 2014 by buedi

[skouras]

exactly my thoughts

something is going on here...:book:

[Flamin_Squirrel]

In the DCS Huey, when the governor is active, nothing happens when you advance the throttle slowly and when you reach max throttle, the engine spools up to 6.600 pretty fast. So the throttle is more like a on/off switch when the Governor is on in the DCS Huey and does not allow you to slowly spool up the engine.

 

Not sure about the rest of your post, but I don't see where you're coming from with the above. I've got the throttle mapped to the LH throttle on my warthog (collective on the RH throttle), and I can spool the engine up nice and slowly, certainly not on/off.

[buedi]

I´m not sure if we are doing the same thing here, so I recorded a short Track file to show what exactly I mean. I should have done that in the first place, would have been much more clear I think.

 

What you see here is a startup with the Governor on. I then slowly increase the throttle and nothing will happen until I hit the throttle max. position. Then the engine will spool up.

I play around with the throttle a bit and with the governor in the on and off / EMER position. I hope you see the difference and I´m really curious if this behaviour is just on my side. If it is I´m eager to find out how to get this properly working :-)

 

I have the axes mapped the other way round than you, but I don´t think this makes a difference, because the throttle is moving in game as I move the throttle on the Warthog.

Huey_Startup_Governor_behaviour.trk

[Flamin_Squirrel]

I watched your track and see exactly what you're talking about. I then tried myself and got the same problem. I don't remember seeing this problem before; I think it's a new one.

 

Good catch. Hopefully we can get this one flagged for the next patch.

[Flamin_Squirrel]

Tried again with the governor in emergency. Throttle motion is smooth in this mode so it would appear it's just norm that's broken. As you've stated, there should be little difference between the two; the only difference being you've got RPM overspeed protection in norm.

[buedi]

It was always like that for me in the Huey and I think I got it pretty early. If you override / turn off the governor, then yes, you can move the throttle smoothly from idle to overspeed all the way up :-)

I never reported this behaviour, because while the Huey was in Beta one point on the Todo list was the startup procedure, which they now changed to include the throttle idle cut off and the possibility of a hot start. I thought when this is done they also overhaul how the governor works. Now it´s out of beta (I think this was the case with 1.2.7) and we still have the same behaviour. Belsimtek also announced that they will still make changes when it´s out of beta, so I hope that they will fix the governor some time in the future. I think there´s not much (or nothing) left then for the startup procedure for the Huey to make it complete in this regard.

[b00ce]

Per the -10, you're not supposed to turn the governor on or off at anything but idle. And in the MTP manual it makes a point to tell you to roll off to idle before switching the governor to EMER or AUTO.

 

CAUTION

Throttle must be at engine idle prior to

switching governor to emergency.

 

a. Throttle - Engine idle.

 

b. GOV switch - EMER.

 

c. Throttle - Slowly increase N1, note

high RPM warning light on at

6800 ± 100 (334±5 rotor) RPM.

 

d. Throttle - Engine idle, GOV

switch to AUTO, carefully increase

throttle to full open, check

N2 6000±50 RPM.

 

C2 2-24

 

I recommend going through the MTF start-up procedure, you'll see all the little subtle things that BST put in that you don't normally notice, like the Bleed band opening and closing. :book:

[-MadCat-]

Concerning the lack of response to throtthe adjustments between idle and max with the governor in auto,

that's reported and already officially confirmed to currently be wrong.

 

http://forums.eagle.ru/showthread.php?t=117921

 

The idle - max "switch" came with 1.2.6.

 

Greetings

MadCat

[buedi]

Thanks Madcat, the comment from EvilBivol-1 in Post #6 was exactly what I was not able to find. This is why I created the Thread. It´s good to see that BST is aware of it and acknowledged it to be a but :thumbup: