Overheating HS780 engines

[J0hn]

Hello chasps

I had a flight from Carlisle to Vigra in Norway today in Rick's Andover C.1 and had a problem keeping the engine temps down.

I scoured the manual for tips and used the on-board checklist to make sure everything was as it should be, but failed to get the engines below about 850°, let alone anywhere near the recommended 770°.
The checklist always had the 'Power' item red-crossed, regardless of where I put it.

I referred to the fuel trim chart and also had a play around with the values but the only way I could even start cooling them was by setting it to 0% and lowering the rpm to a dangerously low level - and this just to attain the aforementioned 850°-odd.

I only had about 780lbs of cargo, including myself and had engaged the fast engine anti-ice system as the OAT was -5°C.







On the return leg, I had the same problem, though I managed this time to avoid going into the red at all, but still well over 800°. This time I remained below 3,000ft and thus managed to avoid negative temperatures and hence more anti-ice heating all round. Whether that has any effect is another matter - what I'm concerned about is my inability to get those temps down in the first place.

Any suggestions gladly taken aboard.

Oh, while we're at it - I also have a problem every time I start up in that the right engine always seems to stick and takes ages to fire up. The left one starts up immediately - it's just the right one that's 'sticky'.
This happens in both the 780 and the 748.

J.

[robbie]

Hi J,
Looking at those strange perameters, I'd guess you'de used some rapid throttle inputs and maybe, just maybe, tripped the prop system into auto feather,
it's the only thing I can think of anyway, I'm sure the experts will have an awnser for you shortly.
In the mean time try operating the feathering motors, that should reset the props to give you some torque and reduce the TGT.

Robbie.

[DaveB]

Hello Matey..

Well.. the correct way to keep engine temps down is by use of the fuel trim (seen on the LH of the checklist with a red X against it). If you don't trim correctly, you'll never get all 4 lamps (above the ALT) out either. If in doubt, keep the checklist open and fuel trim until the X turns to a tick. ;-)

EDIT..
I've looked at those shots again and your 4 lamps are out. However, if the engine temps are still high, they're not trimmed correctly.

ATB

DaveB :tab:

[J0hn]

Thanks for the replies.

I did spend a few minutes playing with the fuel trim, but I found that as soon as I moved it above 0% the temps started rising even more. I'd moved it down to zero because I noticed that the lower it was, the lower the TGT went and apart from lowering the rpm via throttle, nothing else worked.

I do have a separate prop pitch lever set up, but I'm pretty sure that it says in the manual to leave that well alone as it is set automatically by the aircraft.

Well, I'll continue fiddling with that fuel trim on the next flight and see what happens.

I've clocked up a large amount of hours in this aircraft but this is the first time this problem has arisen - at least, the first time I noticed it (and that was only because on my first attempt at this flight ended getting virtually very wet after an engine flameout over the North Sea!).

Cheers
J.

[DaveB]

Hi J0hn

Yup.. under no account use the prop pitch lever on your rig. Prop pitch on this and other Dart aircraft is automatically governed by the throttles so to fiddle with separate pitch levers will give undesirable results ;-)

A fuel trim setting of zero is fully lean and 100 fully rich. Not sure why anything off zero is giving you an over temp condition :think: Difficult to see from your screenies which sim you're using but looking at the sea, I'd guess it's FS9 (though it could be FSX cranked down) :think: Have you changed from XP to Vista or made any other changes that might have upset the way the 780 operates??

ATB

DaveB :tab:

[J0hn]

Hi Dave

no, I've always used it in FSX SP2 and Vista (64).

I don't know why the sea looks grim - I usually get complimented on how the water looks in my sim - but I did recently turn some stuff down (not water though) because I'm running several additional programs as add-ons (like VoxATC, Air Hauler, TIR and suchlike), although I think it's more likely that I had upped the simrate and just reduced it prior to this shot being taken and FSX hadn't caught up with the textures yet.

Anyway I'll do some testing tomorrow on a similar route and see how I get on.

Thanks and GN
J.

[DaveB]

Hi J0hn..

Ah.. FSX. This unfortunately is where I have to part company Though I have it, I don't use it very often and have neither the 748 or 780 installed. Odd that it's something you've only just noticed :think: Hopefully, one of the 'X' users will jump in with some advice ;-)

BTW mate.. smashing sig picture but it's a bit on the large side ;-)

ATB

DaveB :tab:

[J0hn]

GM

I thought it was a little large, but stayed within the guidelines for size (it's 500x146), so was a bit surprised myself - maybe Photobucket resized it slightly.

Anyway - I do have FS9 but tbh I really can't stand much of it in one go. I bought some terrain 'upgrades' but still think that FSX just leaves it for dead. FSX is the first in the FS series I bought as I wasn't too impressed with any up to then (IL-2 and Lock On were my favourites, with or without the 'action') but I bought FS9 just to be able to fly the CS Herc before the FSX version was released.

Anyway, as I said, I'll test and see what happens and get a smaller sig.

bcnu
J.

[DaveB]

Hi J0hn..

A thought occured to me last night about the 780. I wonder if what you're seeing is a combination of the way FSX see's turbo props and the way the fuel trimmers are coded?? :think: I think the engines will work in a 'similar' fashion but I'm not so sure about the gauges as they were coded to work with FS9 and not FSX. While most 'proper' FS9 gauges go over to X with little trouble, differences between the old and new SDK's mean that certain things won't work in one as they do in the other. As you've not seen (or noticed) the problem before, I might be barking up the wrong tree but I wouldn't be surprised if X was the problem ;-) A lot of the guy's here use the 748 (and therefore, I guess the 780) in FSX but I can't recall this problem being highlighted. Perhaps one of em will give it a go and report back. I can't see any reason for the 748 to work and not the 780.. well, not that particular part

ATB

DaveB :tab:

[TSR2]

Give me 10 minutes and I'll check, also running FSX Acc and Vista x64...