fixed wing angle of attack and cruise speed

classic Classic list List threaded Threaded
10 messages Options
Reply | Threaded
Open this post in threaded view
|

fixed wing angle of attack and cruise speed

Chris Efstathiou
Hi.
I was thiniking that if i want to make an airplane to go slower could i
use a higher angle of attack during flight thus increasing lift (within
the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need
or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly
more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a
cruising speed of 110km/h even with low throttle (40%) and at 3 degrees
wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to
a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Loic Drumettaz

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel

_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Chris Efstathiou
Hi.
Got it, thank you very much for your help.
I think i will try to increase pitch with the "pitch_neutral_default" and see what happens.
Btw i am always learning, i didn't knew the cruise throttle setting behavior as you described it, thank you again.
Chris


On 11/19/2013 08:20 PM, Loic Drumettaz wrote:

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Reto Büttner
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).
 
Regards
Reto
 


2013/11/19 Chris <[hidden email]>
Hi.
Got it, thank you very much for your help.
I think i will try to increase pitch with the "pitch_neutral_default" and see what happens.
Btw i am always learning, i didn't knew the cruise throttle setting behavior as you described it, thank you again.
Chris



On 11/19/2013 08:20 PM, Loic Drumettaz wrote:

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel



_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Chris Efstathiou
That's a good idea!
I will implement it right now, all i need is a fuel flow sensor but i know where i can find one i think.
125km with 2kgm AUW !!!
Was it a continuously<a href="http://www.google.gr/url?sa=t&amp;rct=j&amp;q=&amp;esrc=s&amp;source=web&amp;cd=1&amp;cad=rja&amp;ved=0CDEQFjAA&amp;url=http%3A%2F%2Fel.wiktionary.org%2Fwiki%2Fcontinuously&amp;ei=YKOMUprvHsrNhAeLs4HoCw&amp;usg=AFQjCNGy2FBFamvgnxfupgyaUkxnUC7GPg&amp;sig2=tMyhEZbG3HycGCrAs6_YkA&amp;bvm=bv.56643336,d.bGE" onmousedown="return rwt(this,'','','','1','AFQjCNGy2FBFamvgnxfupgyaUkxnUC7GPg','tMyhEZbG3HycGCrAs6_YkA','0CDEQFjAA','','',event)"> powered flight or it had glide sections also?
What was the average air or ground (whatever) speed?
Chris

On 11/20/2013 10:12 AM, Reto Büttner wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).
 
Regards
Reto
 


2013/11/19 Chris <[hidden email]>
Hi.
Got it, thank you very much for your help.
I think i will try to increase pitch with the "pitch_neutral_default" and see what happens.
Btw i am always learning, i didn't knew the cruise throttle setting behavior as you described it, thank you again.
Chris



On 11/19/2013 08:20 PM, Loic Drumettaz wrote:

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel




_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Reto Büttner
Hi Chris
 
See:
 
 
It was continuously powered and the speed was around 75 km/h.
 
Regards
Reto
 


2013/11/20 Chris <[hidden email]>
That's a good idea!
I will implement it right now, all i need is a fuel flow sensor but i know where i can find one i think.
125km with 2kgm AUW !!!
Was it a continuously powered flight or it had glide sections also?
What was the average air or ground (whatever) speed?
Chris


On 11/20/2013 10:12 AM, Reto Büttner wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).
 
Regards
Reto
 


2013/11/19 Chris <[hidden email]>
Hi.
Got it, thank you very much for your help.
I think i will try to increase pitch with the "pitch_neutral_default" and see what happens.
Btw i am always learning, i didn't knew the cruise throttle setting behavior as you described it, thank you again.
Chris



On 11/19/2013 08:20 PM, Loic Drumettaz wrote:

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel




_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel



_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Chris Efstathiou
Ohh my God i am getting old and forget things....
I now got to start working on my X8 wing again he he he
Chris



On 11/20/2013 02:47 PM, Reto Büttner wrote:
Hi Chris
 
See:
 
 
It was continuously powered and the speed was around 75 km/h.
 
Regards
Reto
 


2013/11/20 Chris <[hidden email]>
That's a good idea!
I will implement it right now, all i need is a fuel flow sensor but i know where i can find one i think.
125km with 2kgm AUW !!!
Was it a continuously powered flight or it had glide sections also?
What was the average air or ground (whatever) speed?
Chris


On 11/20/2013 10:12 AM, Reto Büttner wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).
 
Regards
Reto
 


2013/11/19 Chris <[hidden email]>
Hi.
Got it, thank you very much for your help.
I think i will try to increase pitch with the "pitch_neutral_default" and see what happens.
Btw i am always learning, i didn't knew the cruise throttle setting behavior as you described it, thank you again.
Chris



On 11/19/2013 08:20 PM, Loic Drumettaz wrote:

Hi,

If you want to reduce speed without using an airspeed sensor, the easiest is to set nominal pitch using pitch_neutral_default in the airframe configuration.
This will offset the measured pitch.
You can tune pitch_neutral in flight by adding settings/estimation/ins_neutrals.xml in paparazzi center.
Constant airspeed in level flight is then obtained with accurate (no static error) attitude pitch loop.

nominal_cruise_ throttle is a preset of thrust which is corrected by auto throttle loop. Reduce it will only increase the airplane altitude error, but won't help to reduce speed ( at least in steady flight)

Loic

Le 19 nov. 2013 16:41, "Chris" <[hidden email]> a écrit :
Hi.
I was thiniking that if i want to make an airplane to go slower could i use a higher angle of attack during flight thus increasing lift (within the lowest drag envelope of course)?
If i am right what settings other than minimum cruise throttle do i need or is possible to adjust?
I am asking because i have an airplane (the huge Cessna) that can fly more than safely with 80km/h
and have significantly reduced drag but the autopilot gives it a cruising speed of 110km/h even with low throttle (40%) and at 3 degrees wing pitch during flight.
I am searching for those last bits that can decrease fuel consumption to a minimum :-D
Chris


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel




_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel




_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Ben Laurie
In reply to this post by Reto Büttner



On 20 November 2013 08:12, Reto Büttner <[hidden email]> wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).

Cool ... what are these planes?


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

Chris Efstathiou



On 20 November 2013 08:12, Reto Büttner <[hidden email]> wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).

Cool ... what are these planes?



_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
Reply | Threaded
Open this post in threaded view
|

Re: fixed wing angle of attack and cruise speed

agressiva
Hello Reto, what foil you used in the long range flywing ?
Way this design ? and not a more conventional one ?


Date: Sat, 23 Nov 2013 21:23:34 +0200
From: [hidden email]
To: [hidden email]
Subject: Re: [Paparazzi-devel] fixed wing angle of attack and cruise speed




On 20 November 2013 08:12, Reto Büttner <[hidden email]> wrote:
Hi Chris
 
To optimize efficiency you can display an efficiency indicator on the 2D map using papgets. An easy efficiency indicator would be "Speed per Percent Throttle". Better efficiency indicators are "Speed per Fuel Flow" or "Distance per Litre Fuel", but this needs a fuel flow measurement. For electric planes it would be "Speed per Amps" or "Distance per Ah". The simple math needed for these indicators (one division) can be done directly in the papget. Then choose a calm day (no wind), fly large circles and manually play around with the throttle setting (using pitch neutral as described) until you get maximum efficiency. We have done so successfully with our long distance small electric planes (>125km, 140cm wingspan, 2kg weight).

Cool ... what are these planes?



_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel


_______________________________________________ Paparazzi-devel mailing list [hidden email] https://lists.nongnu.org/mailman/listinfo/paparazzi-devel

_______________________________________________
Paparazzi-devel mailing list
[hidden email]
https://lists.nongnu.org/mailman/listinfo/paparazzi-devel