Slow Speed

[alexdm]

Hi, I love the Saab 340 and I just wanted to check if it is only me but I cannot get it to go faster than 140 kts max 155. Is it normal? The documentation included with this plane indicates a VMO from 210 KIAS (25,000 ft) to 250 KIAS (16,000ft). I tried at different altitudes and with different Condition Lever positions but still no faster than 140-155.

 

Thanks!

[Silent_V]

I got the same issue. Have no idea why. I use manual to set the levers but this does not help:(And as far as I remember I saw several posts here ( or somewhere else) complaining about the same issue.<br /><br />Sent from my Galaxy Note via Tapatalk<br /><br />

[mmerelles]

I think you are mixing KIAS (indicated airspeed) & KTAS (true airspeed). Is that possible?

 

At 25,000 feet, assuming average weight onboard, the Saab 340 will deliver 148 KIAS (indicated airspeed) which is 207 KTAS (true airspeed). At higher altitudes the air is much less dense so the KIAS indicator decreases due to less pressure on the tube (indicated airspeed display) but the plane is still moving fast (true airspeed)

 

hope this helps

Edited August 6, 2014 by mmerelles

[eMko]

I also can't get the max cruise speeds - I complained on this forum 2 times with no good response. But I can get the long range cruise speeds without frying the engines, so I just plan the flights with LRC speed + margin for winds.

[JGregory]

Hi, I love the Saab 340 and I just wanted to check if it is only me but I cannot get it to go faster than 140 kts max 155. Is it normal? The documentation included with this plane indicates a VMO from 210 KIAS (25,000 ft) to 250 KIAS (16,000ft). I tried at different altitudes and with different Condition Lever positions but still no faster than 140-155.

 

Thanks!

Vmo is the MAX operating, or "allowable" airspeed… this does not mean the aircraft can, will, or should get to that speed, it is simply a number that should not be exceeded.  You should use the Charts.pdf document to find the speed ranges at various altitudes and power settings.

Edited August 6, 2014 by JGregory

[eMko]

Yes, but alexdm's 140-155 KIAS are quite a low number anyway. I usually got around 170-180 at FL220. At lower flight levels, e.g. FL150, I can get over 200KIAS quite easily. Looks like something is not right in this case.

 

I'm not at home now, but in the evening I can check my speeds again.

Edited August 7, 2014 by eMko

[baudrate43]

Alexdm

 

Were you flying with any ice heaters turned on. I was cruising along at 160 the other day and felt I should be clipping along better than that. I had the stby pitot heater on, that's the only heater I turned on initially. I turned on all the other heaters except boots and slowly watched my speed increase to 190.

 

baudrate43

[JGregory]

Yes, but mmerelles's 140-155 KIAS are quite a low number anyway. I usually got around 170-180 at FL220. At lower flight levels, e.g. FL150, I can get over 200KIAS quite easily. Looks like something is not right in this case.

 

I'm not at home now, but in the evening I can check my speeds again.

Please refer to the speed charts on pages 76-81 in the Charts.pdf.  There are several variables to be considered including altitude, power setting, weight, OAT, etc.  I can easily find mmerelle's numbers, as well as yours, within the normal parameters.  If you find the performance is significantly different from the charts, please document ALL your flight conditions and report them back to us.

Edited August 7, 2014 by JGregory

[Ubbi]

All the people i know with this "Problem" where use the Prop-Levers at the very maximum Position. In this Position the Props are spinning at a to high speed and produce not enough speed forward.

So i bet: if you pull the Prop-Lever back into the normal operation range (min to max but not the little bit above max), you will get much higher speeds (like 220-230 indikated if your Saab is not to heavy)

 

Philip

Edited August 7, 2014 by Ubbi

[eMko]

I'll try that in the evening, but no, I don't put the conditions lever to the end.

[eMko]

Hello,

 

I did a short flight between Glasgow and Manchester, 176 nm, take off weight was 22000lbs. According to the Performance charts manual page 72: at FL170 I should burn 880 lbs of fuel and it should take 50 minutes*. Weather was clear skies with no winds, ISA athmosphere. ECS were on, engine anti ice off.

 

At FL170 in ISA condition there should be -19°C and I should cruise at 214 KIAS / 276 KTAS in cruise power (manual page 77) and the power should be 78 TRQ at 1230 RPM or 73 TRQ at 1330 RPM (pages 17 and 23). Not even close, 25KIAS slower.

 

 

According to advice here I turned on the windshield and prop heating (the pitot tube heating was already on, I'm a bit more comfortable if it's not frozen :-) ). No difference.

 

With engine A/I ON, the speed should be 203 KIAS / 261 KTAS (page 80), max power is 67% TRQ at 1330 RPM (page 24). 20 KIAS slower, better result than previous situation. But I also should say that I always let the airplane stabilize for a couple of minutes, so it's a bit lighter than in previous situation.

 

 

The advisory speed for this flight level should be slightly over 180 KIAS according to page 27 of the manual, that's pretty accurate.

 

I include also the screenshots of the overhead panel - did I do something wrong, please? Do you see something suspicious?

 

 

And a screen of a weight and balance during flight

 

 

BTW after landing the burnt fuel indicator showed 460kg, but the weight and balabce screen showed that there were 1800 lbs of fuel in the tanks; originally there were 3003 lbs. I'm not very good at math at 10:45PM, but I don't think that 460kg is equal to 1200lbs.

 

Thanks for help!

 

* The SID and STAR is not included.

Edited August 7, 2014 by eMko

[Silent_V]

That's what I meant. Even using charts I've never gotten the desired per<br /><br />Sent from my Galaxy Note via Tapatalk<br /><br />

[eMko]

Please refer to the speed charts on pages 76-81 in the Charts.pdf.  There are several variables to be considered including altitude, power setting, weight, OAT, etc.  I can easily find mmerelle's numbers, as well as yours, within the normal parameters.  If you find the performance is significantly different from the charts, please document ALL your flight conditions and report them back to us.

 

Hello,

 

I'm leaving for 2 week vaccation now and I'm leaving all the electric devices at home. If you need more data than I posted, please be patient until I return - I don't own the petroleum-powered steampunk-style computer :-) .

[Goran_M]

I'll be doing some checks on the flight model and making adjustments in the coming days.