Exhaust Gas Temperature rising to early when startup engine.

[P3CFE]

At the moment almost imediately after pressing the startbutton the ECT rises.

In real life this would scare the hack out of me

Normally, at about 10 percent engine rpm, Fuel flow is innitiated, and only than ignition of the mixture is possible.

Small stuff i know, but i don't think it is very difficut to correct, and hee...all for realism  right 

 

[Xupicor]

What is your throttle position when holding the Engine Start button? Both the DCS Huey and the Bell UH-1H/V manual I have here say it should be just a below the IDLE STOP position, but neither one says exactly at which point to start turning it towards IDLE STOP. I gather a 10% N1 is an alright value since we need to confirm rotors start turning at 15%?

If I set it at IDLE STOP (so, PgUp fully and PgDn to get to the locked position) - indeed immediately when I press the Engine Start button Exhaust gauge skyrockets immediately. However, if I set it at just a touch below IDLE STOP position (by pressing Idle Stop Switch -- then I get the Exhaust gauge only positively react after I move the throttle to the IDLE STOP position.

Now, if the rate at which it shoots up is correct - I have no idea. Obviously I haven't flown the Huey or anything else in real life. If you have, can you expand on my observations?

[P3CFE]

thanks for the reply

 

Throttle position is idle. according to normal procedures (but i could be wrong here !)

I wish i had flown a Huey but.. no i did not.

I started a Bo 105 heli once, but then lightoff was ocurring at the moment i moved the throttle lever to idle.

However, n1 was allready above 10 % then, because of the starter that was activated some seconds before pushing the throttle to idle.

In the DC huey, before start, i turn the throttle above idle and then back to the idle stop.

Then i push the starter..(again..i think this is the normal procedure in the huey)

Then immidately the egt rises at the first 1 % of rpm.

This is impossible in real life because the mixture in the gasproducer is not correct at that moment to get a light of.

Normally there also should be a safety in the fuel system to only let fuel pass through the fuel nozzles if n1 rpm is above a range wich provides enough air for a good mixture.

if fuel is allowed into the combustion chamber without enough air (no or little %n1) you wil have a big chance of a burn through in the combustion section....(just a flame slowly burning without beeing noticed by the thermal sensors.)

So it seems wrong to me with the huey at the moment.

 

 

 

 

 

 

 

[admiki]

40 minutes ago, P3CFE said:

thanks for the reply

 

Throttle position is idle. according to normal procedures (but i could be wrong here !)

I wish i had flown a Huey but.. no i did not.

I started a Bo 105 heli once, but then lightoff was ocurring at the moment i moved the throttle lever to idle.

However, n1 was allready above 10 % then, because of the starter that was activated some seconds before pushing the throttle to idle.

In the DC huey, before start, i turn the throttle above idle and then back to the idle stop.

Then i push the starter..(again..i think this is the normal procedure in the huey)

Then immidately the egt rises at the first 1 % of rpm.

This is impossible in real life because the mixture in the gasproducer is not correct at that moment to get a light of.

Normally there also should be a safety in the fuel system to only let fuel pass through the fuel nozzles if n1 rpm is above a range wich provides enough air for a good mixture.

if fuel is allowed into the combustion chamber without enough air (no or little %n1) you wil have a big chance of a burn through in the combustion section....(just a flame slowly burning without beeing noticed by the thermal sensors.)

So it seems wrong to me with the huey at the moment.

 

 

 

 

 

 

 

Real life procedure is to keep throttle just bellow idle stop. Once N1 reaches 40%, you move throttle above idle stop and then back down to idle stop.

Problem we have in DCS is that it does not recognise an axis until it is above idle stop (only explanation I could come up with is to prevent desync between physical axis and throttle in DCS). It should be noted that EGT rise is the same with IRL procedure.

Edited October 30, 2023 by admiki

[Xupicor]

@P3CFE - well, both the DCS Huey manual and UH-1 H/V Operator's Manual dated 1988 say the throttle should be just below idle, not at idle. You can get there, like I mentioned above (or planned to), by pressing the Idle Stop Button (low thumb-side on the collective) to unlock the lower ("below idle") range on the throttle and then PgDn to get it just below the Idle Stop. Indeed, like @admiki mentions, can't get there by using an axis, but using a button/key binding or a mouse is possible.

Kind of a bummer that the axis doesn't work in that range, because my Virpil collective actually has a throttle with an Idle Stop mechanically working like it should (locking part of it out like the Huey does) that I could use for it.

 

@admiki Hm, the order of it would indeed suggest it's 40% N1... I've been pushing it to idle way too soon all this time then. But I never got a hung start below 40% N1 -- I had hung starts (I know) when I waited. Reading through the procedure now, that seems clear just from the order. I don't know why it couldn't click in my head. Thanks for you comment! 

Edited October 30, 2023 by Xupicor

[P3CFE]

Okee, tried what you said..but that isnt working for me, i get the throttle just below idle and i get the same indications ie immidiate lightoff at 2% or so..not possible in real life..

When i was xperimenting with in between postions like halfway fully closed and idle throttle, i at one time, even got a very high EGT and no rotation of the rotor the engine seemed decoupled and burning everything inside it.

The whole starting fase mechanics of the Huey is very off in my opinion.

That beeing said, i think the huey is the best helicopter in dcs because of the flight model.

But things like the start mechanics and the grafics of the interior need an upgrade  the huey is worth it i think.

[Xupicor]

Strange, I didn't get the 2% lightoff at all when doing it by the book. I've got the game slow repaired and metashader/fxo purged after every update. Any mods on?

But yes, the startup procedure is not running as it was on the old flight model and there's a need to look into it. For example, I don't need to hold the start switch till 40% as the book prescribes. It used to be that the engine would spool down if I released below 40% -- now you can just hold it for a bit and off it goes even if you release it way early.