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110 kts Maximum


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Hello

 

Despite carefully replicating the power and torque settings shown in the hand book (e.g Economy Cruise Power 75%  Torque 35 p.s.i at 6000 ft) we can't seem to get an IAS of more that 90 -100 kts.  With a light aircraft (7,400 lb) the tables show that 133 kts would be expected.

Additionally we are burning far more fuel that would be expected and we can't seem to cure a 'nose up' attitude.  Is suspect that these matters are all interrelated. (And even at Maximum Cruise Power settings we can't get more that 110 kts).

 

Does anyone have any thoughts?

 

All the best

 

Mike

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@ Mark and Data63.  Yep - the flaps are up and I am adjusting the props to give the appropriate torque psi.  I am wondering whether I am setting the Autopilot incorrectly because when I adjust the trim she reverts back to the previous setting or loses height

Thanks for showing an interest  - I will have another test flight as soon as I can.

MIke

 

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2 hours ago, expire said:

I am wondering whether I am setting the Autopilot incorrectly because when I adjust the trim she reverts back to the previous setting or loses height

 

So you are talking about when you are flying on autopilot? You cannot adjust the trim when flying on autopilot. You can change the attitude by using the nudge wheel on the yoke pedestal. But if you select ALT hold you ought to get straight and level, so you should be able to top 90-100.

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Hi Guys.  I  recalibrated the propeller pitch and throttle levers on FSUPIC and now she races along at 150 kts without the nose up.  (There seems to be some sensitivity to the order in which the throttle and pitch calibrations are carried out - throttle then pitch).

 

But the next problem to solve is why I cannot get the BETA indicator light to activate.  They illuminate only in reverse - I saw an earler question on this which I will refer to.

 

Mike

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  • 1 month later...

We have made a little progress on this problem.

 

We have the red lever of our Saitek throttle quadrant mapped through FSUIPC as the 'Steering Tiller' (which seems to work in tandem with the rudder).

 

Test have shown that as soon we touch the red lever (even the slightest of touches) the 'plane forgets its engine calibrations, the nose comes up and the airspeed drops to about 100 knots.  the only solution is to press open up FSUIPC and press 'OK' - this resents things to normal.

 

Test are on-going - but I think this is a significant finding.

 

Mike

 

 

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6 hours ago, expire said:

We have the red lever of our Saitek throttle quadrant mapped through FSUIPC as the 'Steering Tiller' (which seems to work in tandem with the rudder).

 

I would wonder if this is doing something like extending the spoilers behind the scenes. I seem to recall that the Aerosoft Catalina does something like this to create drag, even though the Cat doesn't have actual spoilers. You might use something like AFSD to see whether the spoilers are operating. Or maybe there are other candidates (air brakes or something like that?)

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Thanks Mark - I was wondering along similar lines. (I assume that you mean 'imaginary' spoilers - like you describe on the Cat?).  Excuse my ignorance - what is AFSD?

 

Our next test is to map the red lever through FSX rather than FSUIPC (using the FSUIPC assignment options) and see whether that has any impact.

 

But it is good to know that we have found a likley cause of our problems - it was getting very vexing.

 

Mike

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9 hours ago, expire said:

Thanks Mark - I was wondering along similar lines. (I assume that you mean 'imaginary' spoilers - like you describe on the Cat?).  Excuse my ignorance - what is AFSD?

 

 

Have a look here. It's a great little (free) utility that allows you to see a lot of the internal FSX variables live.

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  • 2 weeks later...

Hi Mark,

 

Happy New Year

 

Over the Christmas I was able to sit down and do some serious testing.  Based upon your observations regarding the spoilers I deleted all of the FSX joystick/yolk control assignments and replaced them with FSUIPC assignments and calibrations.  The spoiler function was amongst these.

 

Yay! Success!  She behaves impeccably now  and we have been busy flying around the Scottish islands using VOR and NDBs (no fancy GPS stuff for us - it will never catch on!).

 

There is only one minor niggle - we are unable to decouple the steering tiller (mapped to the red Saitek quadrant lever) from the rudder control - which causes a few problems in flight if the red lever is accidently moved.   So for the time being we have not assigned a tiller control and thus use the rudder pedals whilst taxiing.

 

Have you managed to decouple the tiller axis from the rudder axis in your cockpit?

 

Best regards

 

Mike   

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6 hours ago, expire said:

Have you managed to decouple the tiller axis from the rudder axis in your cockpit?

 

Nah, I use my feet to steer too! I have read that ground steering is one of the less enviable quirks of the Twin Otter :) Glad to hear you got your drag factor sorted, though.

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