Climb Slope, Rule of Thumb Stats - Jul 2005

Take off is a different matter. My flight manual says the take off
distance to clear a 49 foot obstacle is 1050 feet which makes the initial
ratio of climb to horizontal distance more like 21 to 1.

===============================================

Date:         Wed, 6 Jul 2005 11:31:13 -0400
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce Schimmel <bruce@SCHIMMEL.COM>
Subject:      climb slope, rule of thumb stats
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For planning purposes, I'm trying to derive some slope numbers for my
81hp a/c.

at the end of a 2400ft runway run, fully loaded at a density altitude
of about 2000ft,

i  would expect to see (at least) 500 ft/min at 60 knots.

1. How do these performance stats compare to yours?

so (and please tell me if I've got this right):

at 60 knots, given 6000 ft to a nm, then you go forward 1 nm or 6000 in
a minute.

the ratio of vertical speed to horizontal speed would be

500:6000

2. This gives a ratio of 1:12, right?

thanks, Bruce
=========================================================================
Date:         Wed, 6 Jul 2005 09:58:10 -0600
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         William Cotton <cotton@ATMOS.COLOSTATE.EDU>
Subject:      Re: climb slope, rule of thumb stats
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Hi Bruce:

 Why aren't you using 55kts which is the best rate of climb? Bill

-----Original Message-----
From: Ximango Owners Group [mailto:XIMANGO@HOME.EASE.LSOFT.COM] On
Behalf Of Bruce Schimmel
Sent: Wednesday, July 06, 2005 9:31 AM
To: XIMANGO@HOME.EASE.LSOFT.COM
Subject: climb slope, rule of thumb stats

For planning purposes, I'm trying to derive some slope numbers for my
81hp a/c.

at the end of a 2400ft runway run, fully loaded at a density altitude
of about 2000ft,

i  would expect to see (at least) 500 ft/min at 60 knots.

1. How do these performance stats compare to yours?

so (and please tell me if I've got this right):

at 60 knots, given 6000 ft to a nm, then you go forward 1 nm or 6000 in
a minute.

the ratio of vertical speed to horizontal speed would be

500:6000

2. This gives a ratio of 1:12, right?

thanks, Bruce
=========================================================================
Date:         Wed, 6 Jul 2005 16:29:17 -0400
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce Schimmel <bruce@SCHIMMEL.COM>
Subject:      Re: climb slope, rule of thumb stats
In-Reply-To:  <008c01c58243$82274ac0$26315281@chinook>
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I used 60 cause it was a round figure, and would err on the
conservative side in calculating the ratio.

assume 55 kts, therefore 5500 horizontal feet/ minute divided by 500
vertical feet/minute is a

1:11 ratio.



On Jul 6, 2005, at 11:58, William Cotton wrote:

> Hi Bruce:
>
>  Why aren't you using 55kts which is the best rate of climb? Bill
>
> -----Original Message-----
> From: Ximango Owners Group [mailto:XIMANGO@HOME.EASE.LSOFT.COM] On
> Behalf Of Bruce Schimmel
> Sent: Wednesday, July 06, 2005 9:31 AM
> To: XIMANGO@HOME.EASE.LSOFT.COM
> Subject: climb slope, rule of thumb stats
>
> For planning purposes, I'm trying to derive some slope numbers for my
> 81hp a/c.
>
> at the end of a 2400ft runway run, fully loaded at a density altitude
> of about 2000ft,
>
> i  would expect to see (at least) 500 ft/min at 60 knots.
>
> 1. How do these performance stats compare to yours?
>
> so (and please tell me if I've got this right):
>
> at 60 knots, given 6000 ft to a nm, then you go forward 1 nm or 6000 in
> a minute.
>
> the ratio of vertical speed to horizontal speed would be
>
> 500:6000
>
> 2. This gives a ratio of 1:12, right?
>
> thanks, Bruce
>
=========================================================================
Date:         Thu, 7 Jul 2005 09:30:02 -0400
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Ted Gordon <tedjgordon@ATT.NET>
Subject:      Re: climb slope, rule of thumb stats

Dear Bruce:

Your numbers are impeccable; I think 12:1 is correct if you have a climb
rate of 500 feet per minute and a ground speed of 60 knots.

Take off is a different matter. My flight manual says the take off
distance to clear a 49 foot obstacle is 1050 feet which makes the initial
ratio of climb to horizontal distance more like 21 to 1. And that's on a
standard day on a paved runway. Most flight manuals I've seen for other
aircraft give a table of take off distances vs. altitude and temperature,
but my Ximango manual does not. I noted in Holliday's more recent glider
that a table of take off distances was silk screened onto the panel.

I'm going out to the airport today and will check on the tie downs of your
glider and Roland's. Holliday's is snug inside of course. Thanks again to
all of you for your help.

Best
Ted
=========================================================================
Date:         Thu, 7 Jul 2005 09:51:47 -0400
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce Schimmel <bruce@SCHIMMEL.COM>
Subject:      Re: climb slope, rule of thumb stats
In-Reply-To:  <LISTSERV%200507070930021470.B5B0@HOME.EASE.LSOFT.COM>
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Ted,

I calculated my climb rate based on the assumption that I've finished
my take-off roll, and this is what I generally see under loaded
conditions. In some instrument approaches, an a/c's climb ratio is used
to determine if it will clear a known obstacle.

Knowing that the Ximango will do 1:12 after a ground run of 2500 ft
should allow one to determine if an obstacle is too high or too close
to the end of a runway.

 From my experience, it's an absurd untruth for the manual to claim that
the Ximango will clear a 50 ft obstacle at 1100 ft. In whose fantasy?

b.




On Jul 7, 2005, at 09:30, Ted Gordon wrote:

> Dear Bruce:
>
> Your numbers are impeccable; I think 12:1 is correct if you have a
> climb
> rate of 500 feet per minute and a ground speed of 60 knots.
>
> Take off is a different matter. My flight manual says the take off
> distance to clear a 49 foot obstacle is 1050 feet which makes the
> initial
> ratio of climb to horizontal distance more like 21 to 1. And that's on
> a
> standard day on a paved runway. Most flight manuals I've seen for other
> aircraft give a table of take off distances vs. altitude and
> temperature,
> but my Ximango manual does not. I noted in Holliday's more recent
> glider
> that a table of take off distances was silk screened onto the panel.
>
> I'm going out to the airport today and will check on the tie downs of
> your
> glider and Roland's. Holliday's is snug inside of course. Thanks again
> to
> all of you for your help.
>
> Best
> Ted
>
=========================================================================
Date:         Fri, 8 Jul 2005 00:23:28 EDT
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         XimangoUSA@AOL.COM
Subject:      Climb Angles etc.
MIME-Version: 1.0
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Gents, 

1.  Please go back and read your Flight Handbook for the best  rate and best
angle climb speeds.  Don't assume you know what  they are.  Some of your
messages have errors. Nuf ced.
 
2.  Understand that those speeds are for max gross weight of  1874 lbs.  The
speeds are lower for lighter weights.  There  are rules of thumb for how much
lower - Richard Collins is one good  source.  There are probably lots of
others.
 
3.  And, realize that these are zero-wind numbers, which means  that the
climb angle calculations can change a LOT for a headwind or  tailwind.  Twenty
knots of wind changes the climb angle by a huge  amount.
 
4.  Finally, realize that these numbers are for  zero-lift.  Since you are
flying a glider, you should be more aware  of this dimension that an airplane
pilot.  I'm sure you recognize that  400 fpm of sink from the off-side of a
strong thermal can ruin your whole  day in the situations you are contemplating
when doing these calculations!
 
Bottom Line:  If you are going to enter into this kind of a  dialog with
yourself about climb rates and angles for your Ximango, keep your  eyeballs out
and focus on on the big picture!  There is nothing wrong with  doing static
climb calculations, but "caveat pilatus."
 
Ximango USA