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Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Jan 24, 2016 6:04 pm Post subject: Numbers

Couple questions

Has anyone reached a concensus on V speeds, or is there much variation 

between individual aircraft? I'd like to have starting points for 

Vs(vans gives Vso), Vx, Vy, Va and Vmmo.



Second question, for those that got a higher gross wt than Van's 

recommended 2700, did you come up with a justification for your DAR?

Something like whether Van's figure is for utility category or normal 

category? I know on 2 place RV's folks have calculated back from the 

known requirements for aerobatic flight to show that for the stated 

aerobatic wt and balance Gs that a certain wt would fall withing normal 

or utility G limits. Of cpurse that doesn't work for the -10 that isn't 

designed for aerobatic use. Not saying one needs justification, but 

would be nice to have.

Kelly

finally finishing

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Sun Jan 24, 2016 7:31 pm Post subject: Numbers

Here's what I use.  I'm sure there's debate about what constitutes "best glide" and other parameters.



I can't speak to GW increases.

--Dave

On Sun, Jan 24, 2016 at 5:55 PM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 Couple questions

 Has anyone reached a concensus on V speeds, or is there much variation between individual aircraft? I'd like to have starting points for Vs(vans gives Vso), Vx, Vy, Va and Vmmo.

 

 Second question, for those that got a higher gross wt than Van's recommended 2700, did you come up with a justification for your DAR?

 Something like whether Van's figure is for utility category or normal category? I know on 2 place RV's folks have calculated back from the known requirements for aerobatic flight to show that for the stated aerobatic wt and balance Gs that a certain wt would fall withing normal or utility G limits. Of cpurse that doesn't work for the -10 that isn't designed for aerobatic use. Not saying one needs justification, but would be nice to have.

 Kelly

 finally finishing

 

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jdriggs49(at)msn.com
Guest

Posted: Sun Jan 24, 2016 7:32 pm Post subject: Numbers

My DAR never said anything about my using 2800 pounds.



Sent from my iPad



 	  Quote: 	
		   On Jan 24, 2016, at 8:20 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 

 

 

 Couple questions

 Has anyone reached a concensus on V speeds, or is there much variation between individual aircraft? I'd like to have starting points for Vs(vans gives Vso), Vx, Vy, Va and Vmmo.

 

 Second question, for those that got a higher gross wt than Van's recommended 2700, did you come up with a justification for your DAR?

 Something like whether Van's figure is for utility category or normal category? I know on 2 place RV's folks have calculated back from the known requirements for aerobatic flight to show that for the stated aerobatic wt and balance Gs that a certain wt would fall withing normal or utility G limits. Of cpurse that doesn't work for the -10 that isn't designed for aerobatic use. Not saying one needs justification, but would be nice to have.

 Kelly

 finally finishing

kearney

Joined: 20 Sep 2008
Posts: 563

Posted: Mon Jan 25, 2016 7:06 am Post subject: Re: Numbers

Hi Dave



I was looking at your V speeds and noticed that the Vne is 200KIAS.  The Vne for the -10 should be 200 KTAS according to Vans.



Cheers



Les

EdKranz

Joined: 29 Dec 2010
Posts: 132
Location: Hastings, MN

Posted: Mon Jan 25, 2016 7:06 am Post subject: Numbers

My DAR didn't question it at all either. He just confirmed that I'd be testing the flight envelope at full gross, whatever I chose (2800#). I don't have the numbers with me, but I think stall only went up like 1 knot at 2800# vs me solo w/ full fuel. 



On Sun, Jan 24, 2016 at 9:29 PM, Danny Riggs <jdriggs49(at)msn.com (jdriggs49(at)msn.com)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Danny Riggs <jdriggs49(at)msn.com (jdriggs49(at)msn.com)>

 

 My DAR never said anything about my using 2800 pounds.

_________________
Ed Kranz
RV10
Finishing
www.edandcolleen.com

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Mon Jan 25, 2016 5:32 pm Post subject: Numbers

Les,



I'll add an asterisk:

*Standard day, Sea Level  

On Mon, Jan 25, 2016 at 7:06 AM, kearney <kearney(at)shaw.ca (kearney(at)shaw.ca)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: "kearney" <kearney(at)shaw.ca (kearney(at)shaw.ca)>

 

 Hi Dave

 

 I was looking at your V speeds and noticed that the Vne is 200KIAS.  The Vne for the -10 should be 200 KTAS according to Vans.

 

 Cheers

 

 Les

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=452261#452261

 

 

 

 

 

 

 

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_________________
--Dave
KWVI

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Mon Jan 25, 2016 7:55 pm Post subject: Numbers

OK, I really did add an asterisk to the AOM.  The checklist (Appendix 1 to the AOM) will probably be inaccurate for a while.  See attached.



Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape.



--Dave





On Mon, Jan 25, 2016 at 5:25 PM, David Saylor <saylor.dave(at)gmail.com (saylor.dave(at)gmail.com)> wrote:

 	  Quote: 	
		  Les,



I'll add an asterisk:

*Standard day, Sea Level  

On Mon, Jan 25, 2016 at 7:06 AM, kearney <kearney(at)shaw.ca (kearney(at)shaw.ca)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: "kearney" <kearney(at)shaw.ca (kearney(at)shaw.ca)>

 

 Hi Dave

 

 I was looking at your V speeds and noticed that the Vne is 200KIAS.  The Vne for the -10 should be 200 KTAS according to Vans.

 

 Cheers

 

 Les

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=452261#452261

 

 

 

 

 

 

 

 ===========

 br> fts!)

 r> > w.buildersbooks.com" rel="noreferrer" target="_blank">www.buildersbooks.com

 rel="noreferrer" target="_blank">http://www.matronics.com/contribution

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 -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?RV10-List

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 eferrer" target="_blank">http://forums.matronics.com

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--Dave
KWVI

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Mon Jan 25, 2016 8:10 pm Post subject: Re: Numbers

 	  EdKranz wrote: 	
		  My DAR didn't question it at all either. He just confirmed that I'd be testing the flight envelope at full gross, whatever I chose (2800#). I don't have the numbers with me, but I think stall only went up like 1 knot at 2800# vs me solo w/ full fuel. 



On Sun, Jan 24, 2016 at 9:29 PM, Danny Riggs <jdriggs49> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Danny Riggs <jdriggs49>

 

 My DAR never said anything about my using 2800 pounds.

	
	




Stall speed goes up like the square root of the weight, so a 4% increase in gross raises Vs 2% which is about 1knot. But solo you may have been 20% under gross, so Vs should have dropped 10%, or about 6 knots, not 1.



To the OP: Va is usually a calculated speed and, unless there is some reason to make it smaller, is usually the square root of the design load limit times the stall speed. Load limit = 3.8, square root of 3.8 = 1.95, multiply that tiimes Vs1 to get Va.

_________________
Bob Turner
RV-10 QB

dmaib@me.com

Joined: 25 Apr 2006
Posts: 455
Location: New Smyrna Beach, Florida

Posted: Mon Jan 25, 2016 8:23 pm Post subject: Re: Numbers

Dave Saylor wrote: "Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape."

I am not 100% sure, but I think my GRT Hxr allows me to set the VNE bug using IAS or TAS. I seem to remember that on the setup. I will check it out when I go to the airport tomorrow.

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

kearney

Joined: 20 Sep 2008
Posts: 563

Posted: Mon Jan 25, 2016 8:25 pm Post subject: Numbers

Hi Dave

 

What I did was calculate at Vne kn KIAS and used that on my AFS 4500 screens. Not perfect but it seems to work for me. 

 

Cheers

 

Les

 

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of David Saylor

Sent: Monday, January 25, 2016 8:45 PM

To: rv10-list(at)matronics.com

Subject: Re: Re: Numbers

 

OK, I really did add an asterisk to the AOM.  The checklist (Appendix 1 to the AOM) will probably be inaccurate for a while.  See attached.

 



Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape.

 

--Dave





 

On Mon, Jan 25, 2016 at 5:25 PM, David Saylor <saylor.dave(at)gmail.com (saylor.dave(at)gmail.com)> wrote:

Les,

 



I'll add an asterisk:



 



*Standard day, Sea Level  

 

On Mon, Jan 25, 2016 at 7:06 AM, kearney <kearney(at)shaw.ca (kearney(at)shaw.ca)> wrote:

--> RV10-List message posted by: "kearney" <kearney(at)shaw.ca (kearney(at)shaw.ca)>



Hi Dave



I was looking at your V speeds and noticed that the Vne is 200KIAS.  The Vne for the -10 should be 200 KTAS according to Vans.



Cheers



Les





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=452261#452261



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===========

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Jan 25, 2016 8:36 pm Post subject: Numbers

Dynon Skyview allows setting Vne as KTAS



On 1/25/2016 9:23 PM, dmaib(at)me.com wrote:

 	  Quote: 	
		   



 Dave Saylor wrote: "Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape."

 I am not 100% sure, but I think my GRT Hxr allows me to set the VNE bug using IAS or TAS. I seem to remember that on the setup. I will check it out when I go to the airport tomorrow.



 --------

 David Maib

 RV-10 #40559

 New Smyrna Beach, FL





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=452279#452279

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Mon Jan 25, 2016 8:55 pm Post subject: Numbers

Nice.



do not archive

On Mon, Jan 25, 2016 at 8:32 PM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 	  Quote: 	
		  --> RV10-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 Dynon Skyview allows setting Vne as KTAS

 

 On 1/25/2016 9:23 PM, dmaib(at)me.com (dmaib(at)me.com) wrote:

  	  Quote: 	
		   --> RV10-List message posted by: "dmaib(at)me.com (dmaib(at)me.com)" <dmaib(at)me.com (dmaib(at)me.com)>

 

 Dave Saylor wrote: "Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape."

 

 

 I am not 100% sure, but I think my GRT Hxr allows me to set the VNE bug using IAS or TAS. I seem to remember that on the setup. I will check it out when I go to the airport tomorrow.

 

 --------

 David Maib

 RV-10 #40559

 New Smyrna Beach, FL

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=452279#452279

 

 

 

 

 

 

 

 

 

 

 	
 

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_________________
--Dave
KWVI

Dave Saylor

Joined: 11 Jan 2015
Posts: 209
Location: GILROY, CA

Posted: Mon Jan 25, 2016 9:00 pm Post subject: Numbers

Les,



I may make up a placard some day (I have one for a few VAs at various weights) but for now I'll try to remember to keep it under 200KTAS.

Thanks for the reminder,

--Dave

On Mon, Jan 25, 2016 at 8:22 PM, Les Kearney <kearney(at)shaw.ca (kearney(at)shaw.ca)> wrote:

 	  Quote: 	
		  

Hi Dave

 

What I did was calculate at Vne kn KIAS and used that on my AFS 4500 screens. Not perfect but it seems to work for me. 

 

Cheers

 

Les

 

From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)] On Behalf Of David Saylor

Sent: Monday, January 25, 2016 8:45 PM

To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

Subject: Re: Re: Numbers

 

OK, I really did add an asterisk to the AOM.  The checklist (Appendix 1 to the AOM) will probably be inaccurate for a while.  See attached.

 



Which makes me wonder:  does anyone have an EFIS that presents VNE in terms of TAS?  My AF3400 does not, but it displays TAS below the IAS tape.

 

--Dave





 

On Mon, Jan 25, 2016 at 5:25 PM, David Saylor <saylor.dave(at)gmail.com (saylor.dave(at)gmail.com)> wrote:

Les,

 



I'll add an asterisk:



 



*Standard day, Sea Level  

 

On Mon, Jan 25, 2016 at 7:06 AM, kearney <kearney(at)shaw.ca (kearney(at)shaw.ca)> wrote:

--> RV10-List message posted by: "kearney" <kearney(at)shaw.ca (kearney(at)shaw.ca)>



Hi Dave



I was looking at your V speeds and noticed that the Vne is 200KIAS.  The Vne for the -10 should be 200 KTAS according to Vans.



Cheers



Les





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=452261#452261



===========

br> fts!)

r> > w.buildersbooks.com" rel="noreferrer" target="_blank">www.buildersbooks.com

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===========

_________________
--Dave
KWVI

dmaib@me.com

Joined: 25 Apr 2006
Posts: 455
Location: New Smyrna Beach, Florida

Posted: Tue Jan 26, 2016 3:05 pm Post subject: Re: Numbers

Checked today and GRT Hxr allows display of TAS VNE as IAS. So, today at 3500 feet msl and about 12 degrees C, my VNE was shown as about 191 KIAS. I haven't had a chance to check that on the whiz wheel, but the number seemed reasonable.

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Tue Jan 26, 2016 5:18 pm Post subject: Re: Numbers

I'm sure Vans' lawyers are telling him to never say anything, but I do wish the company was a little more forth-coming. Was the prototype dived to some speed? At what altitude (surely higher than sea level)? This whole business of specifying Vne as a TAS, when the FARs require specifying it (along with altitudes, if necessary) in IAS for normally certified aircraft, just bothers me.



PS Dave, your ias/tas conversion looks about right to me.

_________________
Bob Turner
RV-10 QB

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Tue Jan 26, 2016 7:34 pm Post subject: Numbers

Van's has a white paper on the subject on their website. Thy physics say 

the design flutter speed is a function of TAS. They make the case that 

extra horsepower via turbo or other engine mods risks being able to 

exceed the number in level cruise at altitude around 12K and up.

Type certified aircraft have to convert that to IAS with some empirical 

evidence of margin of safety via dive testing. Doing the testing is 

likely to be rather expensive by the time you instrument the airframe, 

mount drag chutes, quick release doors and risk loss of the aircraft if 

calculations are wrong. While loss of an aileron is relatively benign, 

loss of elevator or rudder is considerably more serious.



On 1/26/2016 6:18 PM, Bob Turner wrote:

 	  Quote: 	
		   



 I'm sure Vans' lawyers are telling him to never say anything, but I do wish the company was a little more forth-coming. Was the prototype dived to some speed? At what altitude (surely higher than sea level)? This whole business of specifying Vne as a TAS, when the FARs require specifying it (along with altitudes, if necessary) in IAS for normally certified aircraft, just bothers me.



 PS Dave, your ias/tas conversion looks about right to me.



 --------

 Bob Turner

 RV-10 QB





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=452329#452329

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Tue Jan 26, 2016 8:31 pm Post subject: Re: Numbers

 	  Kellym wrote: 	
		  Van's has a white paper on the subject on their website. Thy physics say 

the design flutter speed is a function of TAS. They make the case that 

extra horsepower via turbo or other engine mods risks being able to 

exceed the number in level cruise at altitude around 12K and up.



	
[/quote]



I've read the white paper. It contains a certain amount of nonsense. Flutter depends on TAS and air density. IAS depends on TAS and density. So between TAS, IAS, and density one can choose any two to express the equations. For example, with lift, we often choose IAS and density, because the density magically drops out of the equations. Does this mean lift doesn't depend on density? Of course not. It's included in just the right way in the definition of IAS. Now with flutter, there are many possible modes, and the relationship between density and TAS varies from one mode to the next. So it is not possible to define it away for all cases. You need, in general, two variables. It is not correct to say "flutter depends on (only) TAS".

This business of higher than standard power is a red herring. Any standard -10, when light, can climb well into the flight levels. Nose it over to come down, and you can easily get as high a speed as desired. I would like to know, whether thru analysis or testing, where certain airspeeds (IAS or TAS) AND densities need to be observed as limiting.

_________________
Bob Turner
RV-10 QB

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Jan 27, 2016 5:20 am Post subject: Numbers

I thought there general requirement to specify Vne in IAS for certified 

planes is because many planes did not have direct TAS instrumentation.



I assume that any inaccuracies resulting from density effects are 

reflected in conservative Vne figures.



We all want the freedom to build the way we want them.  I'd be very 

hesitant to publish such numbers given my lack of control over the product.



Bill "just thinking out loud"



On 1/26/2016 11:31 PM, Bob Turner wrote:

 	  Quote: 	
		   I've read the white paper. It contains a certain amount of nonsense. 

 Flutter depends on TAS and air density. IAS depends on TAS and 

 density. So between TAS, IAS, and density one can choose any two to 

 express the equations. For example, with lift, we often choose IAS and 

 density, because the density magically drops out of the equations. 

 Does this mean lift doesn't depend on density? Of course not. It's 

 included in just the right way in the definition of IAS. Now with 

 flutter, there are many possible modes, and the relationship between 

 density and TAS varies from one mode to the next. So it is not 

 possible to define it away for all cases. You need, in general, two 

 variables. It is not correct to say "flutter depends on (only) TAS". 

 This business of higher than standard power is a red herring. Any 

 standard -10, when light, can climb well into the flight levels. Nose 

 it over to come down, and you can easily get as high a speed as 

 desired. I would like to know, whether thru analysis or testing, where 

 certain airspeeds (IAS or TAS) AND densities need to be observed as 

 limiting. -------- Bob Turner RV-10 QB Read this topic online here: 

 http://forums.matronics.com/viewtopic.php?p=452335#452335 

 http://www.matronics.com/contribution 


	




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Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Wed Jan 27, 2016 7:07 am Post subject: Numbers

Seems like a few facts are muddled in this discussion.

1. True airspeed is a direct function of density altitude, there is no 

independent variable.

2. Flutter is a direct function of TAS, as the speed of air over the 

control surface induces a certain harmonic frequency.

3. Most aircraft can exceed Vne or design flutter speed in a dive. Some 

turbo charged aircraft and higher power normally aspirated aircraft can 

exceed Vne in level flight. That is what Vans was concerned about.

4. Virtually all turbine aircraft have a "barber pole" speed that is 

their limit for given density altitude. Above certain altitude it 

becomes a mach number. Same exact concept, just at higher speeds. The do 

not exceed speed varies substantially as they go higher.

There are ways to increase the design flutter speed by upgrading control 

surfaces. I don't know much about that beyond weight and stiffness of 

the surface, along with counter balancing are factors.

On 1/27/2016 6:15 AM, Bill Watson wrote:

 	  Quote: 	

 I thought there general requirement to specify Vne in IAS for certified

 planes is because many planes did not have direct TAS instrumentation.

 I assume that any inaccuracies resulting from density effects are

 reflected in conservative Vne figures.

 We all want the freedom to build the way we want them.  I'd be very

 hesitant to publish such numbers given my lack of control over the product.

 Bill "just thinking out loud"

 On 1/26/2016 11:31 PM, Bob Turner wrote:

> I've read the white paper. It contains a certain amount of nonsense.

> Flutter depends on TAS and air density. IAS depends on TAS and

> density. So between TAS, IAS, and density one can choose any two to

> express the equations. For example, with lift, we often choose IAS and

> density, because the density magically drops out of the equations.

> Does this mean lift doesn't depend on density? Of course not. It's

> included in just the right way in the definition of IAS. Now with

> flutter, there are many possible modes, and the relationship between

> density and TAS varies from one mode to the next. So it is not

> possible to define it away for all cases. You need, in general, two

> variables. It is not correct to say "flutter depends on (only) TAS".

> This business of higher than standard power is a red herring. Any

> standard -10, when light, can climb well into the flight levels. Nose

> it over to come down, and you can easily get as high a speed as

> desired. I would like to know, whether thru analysis or testing, where

> certain airspeeds (IAS or TAS) AND densities need to be observed as

> limiting. -------- Bob Turner RV-10 QB Read this topic online here:

> http://forums.matronics.com/viewtopic.php?p=452335#452335

> http://www.matronics.com/contribution

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

glastar(at)gmx.net
Guest

Posted: Wed Jan 27, 2016 7:44 am Post subject: Numbers

Bob,



you always could convert the TAS to a IAS/Altitude table if you want, 

the beauty of having it in TAS (and maybe your EFIS can display this as 

well), is that

wherever you fly your limit will be correct.



I myself prefer it that way instead of looking at a table buried on the 

lower left panel like in a Cirrus.



my 2 cents Werner



On 27.01.2016 02:18, Bob Turner wrote:

 	  Quote: 	
		   



 I'm sure Vans' lawyers are telling him to never say anything, but I do wish the company was a little more forth-coming. Was the prototype dived to some speed? At what altitude (surely higher than sea level)? This whole business of specifying Vne as a TAS, when the FARs require specifying it (along with altitudes, if necessary) in IAS for normally certified aircraft, just bothers me.

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