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RV-7 Best climb and rate of climb

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lrsecaldwell(at)earthlink
Guest

Posted: Wed Mar 05, 2008 1:51 pm Post subject: RV-7 Best climb and rate of climb

We have a RV-7 with O0360 and FP prop (72-85).



We are in the phase I process and measuring various speeds using the 

2000 ft to 3000 ft and stopwatch metnod.



We get best glide at about 85 knots which seems about right.



However we are having difficulties getting consistant  climb speeds due 

to thermals and wind shears.



Vy seems to be 90 to 95 knots(seems high)  with best rate of climb 

around 70 knots.



What are other RV-7s with O360s and FPP getting?



Thanks.



Roger

khorton01(at)rogers.com
Guest

Posted: Wed Mar 05, 2008 3:16 pm Post subject: RV-7 Best climb and rate of climb

On 5 Mar 2008, at 16:44, Lapsley R. and Sandra E. Caldwell wrote:



 	  Quote: 	
		   

 <lrsecaldwell(at)earthlink.net>



 We have a RV-7 with O0360 and FP prop (72-85).



 We are in the phase I process and measuring various speeds using  

 the 2000 ft to 3000 ft and stopwatch metnod.



 We get best glide at about 85 knots which seems about right.



 However we are having difficulties getting consistant  climb speeds  

 due to thermals and wind shears.



 Vy seems to be 90 to 95 knots(seems high)  with best rate of climb  

 around 70 knots.



 What are other RV-7s with O360s and FPP getting?



 Thanks.



 Roger

khorton01(at)rogers.com
Guest

Posted: Wed Mar 05, 2008 3:25 pm Post subject: RV-7 Best climb and rate of climb

On 5 Mar 2008, at 16:44, Lapsley R. and Sandra E. Caldwell wrote:



 	  Quote: 	
		   

 <lrsecaldwell(at)earthlink.net>



 We have a RV-7 with O0360 and FP prop (72-85).



 We are in the phase I process and measuring various speeds using  

 the 2000 ft to 3000 ft and stopwatch metnod.



 We get best glide at about 85 knots which seems about right.



 However we are having difficulties getting consistant  climb speeds  

 due to thermals and wind shears.



 Vy seems to be 90 to 95 knots(seems high)  with best rate of climb  

 around 70 knots.


	


I can't help you with any comparative performance, but I can offer  

some comments that might help you get better data.  At low altitudes,  

such as 2000 to 3000 ft, there is little hope of getting good data  

except in a short period after sunrise.  As soon as the thermals  

start there is no point in trying to do any more low altitude  

performance flight testing.  If you want good data you need to be  

cranking the engine when the sun peeks above the horizon.  In the  

summer that will mean a very early start, but it is the only way to  

get smooth air.  On some days you might only get 30 minutes of  

testing before you can start to feel the light bumps from thermals,  

while on other days you might get several hours of testing.  Mornings  

with a high overcast are the best, as that reduces the amount of sun  

heating the ground, which delays the start of the thermals.  Once you  

can start to feel any perceptible turbulence from thermals, there is  

no point in trying to record performance data, as it won't be very  

accurate.



Even early in the morning, the wind speed and direction will usually  

change with altitude, and this affects the results.  You can minimize  

the errors induced by wind change with altitude by doing two runs at  

each climb speed, with the two runs on headings that differ by 180  

degrees.  The effect of wind on the two runs will be in the opposite  

sense, so if you average the rates of climb you will mostly cancel  

out the effects of this wind shear.



Good luck,



--

Kevin Horton

RV-8 (Finishing Kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

tracy(at)rotaryaviation.c
Guest

Posted: Wed Mar 05, 2008 4:26 pm Post subject: RV-7 Best climb and rate of climb

My guess is:

 Best glide seems to be higher than Vy on my RV-4 (or most any airplane with a FP prop) because the higher airspeed allows the engine to turn faster and make more power.  This more than makes up for the increased drag at the higher speed (up to a certain point of course). A CS prop changes the picture.

   

   Your numbers are almost identical to mine.  

  

 Tracy Crook

 On Wed, Mar 5, 2008 at 4:44 PM, Lapsley R. and Sandra E. Caldwell <lrsecaldwell(at)earthlink.net (lrsecaldwell(at)earthlink.net)> wrote:

 [quote]--> RV-List message posted by: "Lapsley R. and Sandra E. Caldwell" <lrsecaldwell(at)earthlink.net (lrsecaldwell(at)earthlink.net)>

 

We have a RV-7 with O0360 and FP prop (72-85).



We are in the phase I process and measuring various speeds using the

2000 ft to 3000 ft and stopwatch metnod.



We get best glide at about 85 knots which seems about right.

 

However we are having difficulties getting consistant  climb speeds due

to thermals and wind shears.



Vy seems to be 90 to 95 knots(seems high)  with best rate of climb

around 70 knots.



What are other RV-7s with O360s and FPP getting?

  [quote][b]

tracy(at)rotaryaviation.c
Guest

Posted: Wed Mar 05, 2008 4:28 pm Post subject: RV-7 Best climb and rate of climb

Opps, that should have read "Best glide seems to be LOWER than Vy"

 T.C. 

 On Wed, Mar 5, 2008 at 7:22 PM, Tracy Crook <tracy(at)rotaryaviation.com (tracy(at)rotaryaviation.com)> wrote:

 [quote] My guess is:

 Best glide seems to be higher than Vy on my RV-4 (or most any airplane with a FP prop) because the higher airspeed allows the engine to turn faster and make more power.  This more than makes up for the increased drag at the higher speed (up to a certain point of course). A CS prop changes the picture.

   

   Your numbers are almost identical to mine.  

  

 Tracy Crook

  

  On Wed, Mar 5, 2008 at 4:44 PM, Lapsley R. and Sandra E. Caldwell <lrsecaldwell(at)earthlink.net (lrsecaldwell(at)earthlink.net)> wrote:

 [quote]--> RV-List message posted by: "Lapsley R. and Sandra E. Caldwell" <lrsecaldwell(at)earthlink.net (lrsecaldwell(at)earthlink.net)>

 

We have a RV-7 with O0360 and FP prop (72-85).



We are in the phase I process and measuring various speeds using the

2000 ft to 3000 ft and stopwatch metnod.



We get best glide at about 85 knots which seems about right.

 

However we are having difficulties getting consistant  climb speeds due

to thermals and wind shears.



Vy seems to be 90 to 95 knots(seems high)  with best rate of climb

around 70 knots.



What are other RV-7s with O360s and FPP getting?

 



[b]

khorton01(at)rogers.com
Guest

Posted: Wed Mar 05, 2008 5:45 pm Post subject: RV-7 Best climb and rate of climb

On 5 Mar 2008, at 16:44, Lapsley R. and Sandra E. Caldwell wrote:



 	  Quote: 	
		   

 <lrsecaldwell(at)earthlink.net>



 Vy seems to be 90 to 95 knots(seems high)  with best rate of climb  

 around 70 knots.


	


One more thing: we either have a typo here, or a terminology  

problem.  Vy is the speed for best rate of climb.



--

Kevin Horton

RV-8 (Finishing Kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

khorton01(at)rogers.com
Guest

Posted: Thu Mar 06, 2008 5:57 am Post subject: RV-7 Best climb and rate of climb

On 5 Mar 2008, at 18:22, Kevin Horton wrote:

 	  Quote: 	
		   On 5 Mar 2008, at 16:44, Lapsley R. and Sandra E. Caldwell wrote:

> 

> <lrsecaldwell(at)earthlink.net>

>

> We have a RV-7 with O0360 and FP prop (72-85).

>

> We are in the phase I process and measuring various speeds using  

> the 2000 ft to 3000 ft and stopwatch metnod.

>

> We get best glide at about 85 knots which seems about right.

>

> However we are having difficulties getting consistant  climb  

> speeds due to thermals and wind shears.

>

> Vy seems to be 90 to 95 knots(seems high)  with best rate of climb  

> around 70 knots.

 I can't help you with any comparative performance, but I can offer  

 some comments that might help you get better data.  At low  

 altitudes, such as 2000 to 3000 ft, there is little hope of getting  

 good data except in a short period after sunrise.  As soon as the  

 thermals start there is no point in trying to do any more low  

 altitude performance flight testing.  If you want good data you  

 need to be cranking the engine when the sun peeks above the  

 horizon.  In the summer that will mean a very early start, but it  

 is the only way to get smooth air.  On some days you might only get  

 30 minutes of testing before you can start to feel the light bumps  

 from thermals, while on other days you might get several hours of  

 testing.  Mornings with a high overcast are the best, as that  

 reduces the amount of sun heating the ground, which delays the  

 start of the thermals.  Once you can start to feel any perceptible  

 turbulence from thermals, there is no point in trying to record  

 performance data, as it won't be very accurate.

 Even early in the morning, the wind speed and direction will  

 usually change with altitude, and this affects the results.  You  

 can minimize the errors induced by wind change with altitude by  

 doing two runs at each climb speed, with the two runs on headings  

 that differ by 180 degrees.  The effect of wind on the two runs  

 will be in the opposite sense, so if you average the rates of climb  

 you will mostly cancel out the effects of this wind shear.

One more thing - it may be more productive to delay detailed  

performance testing until you are out of the flight test phase so you  

can carry someone to record data.  It can be very difficult to  

accurately fly the aircraft, keep a look out for traffic, and record  

climb data.  If you try to do it all yourself, you probably won't  

hold airspeed as accurately as desired, which will make the results  

inconsistent.  It is much easier if you can divide the tasks between  

two people.  Just make sure you agree on which of you is in charge of  

looking for traffic, or you might find that neither of you is doing it.

For phase one flight testing, if I didn't have an automatic data  

logger, I would probably just do very rudimentary performance tests.   

Then once I could legally carry someone to record data I would do the  

detailed performance testing.

Fly safe,

--

Kevin Horton

RV-8 (Finishing Kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

mcculleyja(at)starpower.n
Guest

Posted: Thu Mar 06, 2008 9:18 am Post subject: RV-7 Best climb and rate of climb

An additional suggestion to add to Kevin's comments is to see if you can 

borrow an electronic barograph to carry aboard during your climb 

performance testing. These are reasonably common among soaring club 

pilots as part of altitude-record flight requirements.



With the barograph you will have a precise altitude-versus-time record 

that you can study after the flight to determine the instantaneous as 

well as average rate of climb during all your controlled speed climbs. 

All you need additionally is to keep a record of the target airspeed 

during each climb so you can correlate the performance shown by the 

barograph recordings after the flight. Where possible, set the barograph 

to record at the shortest time interval available such as every second. 

Check ahead of time to be sure the fastest recording rate will still 

give the barograph enough capacity to operate without running out of 

storage space before your intended flight duration. Whoever you can 

obtain the barograph from should be able to also provide the operating 

manual which will show this capability.



If you don't know of any Soaring Clubs in your area, contact the 

national headquarters for the closest club by e-mailing the National 

Headquarters at:   http://www.ssa.org/



Jim McCulley

---------------------------------------------------------------------------------------- 

Kevin Horton wrote:

 	  Quote: 	
		   

 

 

 On 5 Mar 2008, at 18:22, Kevin Horton wrote:

 

> On 5 Mar 2008, at 16:44, Lapsley R. and Sandra E. Caldwell wrote:

>

>> 

>> <lrsecaldwell(at)earthlink.net>

>>

>> We have a RV-7 with O0360 and FP prop (72-85).

>>

>> We are in the phase I process and measuring various speeds using  the 

>> 2000 ft to 3000 ft and stopwatch metnod.

>>

>> We get best glide at about 85 knots which seems about right.

>>

>> However we are having difficulties getting consistant  climb  speeds 

>> due to thermals and wind shears.

>>

>> Vy seems to be 90 to 95 knots(seems high)  with best rate of climb  

>> around 70 knots.

> I can't help you with any comparative performance, but I can offer  

> some comments that might help you get better data.  At low  altitudes, 

> such as 2000 to 3000 ft, there is little hope of getting  good data 

> except in a short period after sunrise.  As soon as the  thermals 

> start there is no point in trying to do any more low  altitude 

> performance flight testing.  If you want good data you  need to be 

> cranking the engine when the sun peeks above the  horizon.  In the 

> summer that will mean a very early start, but it  is the only way to 

> get smooth air.  On some days you might only get  30 minutes of 

> testing before you can start to feel the light bumps  from thermals, 

> while on other days you might get several hours of  testing.  Mornings 

> with a high overcast are the best, as that  reduces the amount of sun 

> heating the ground, which delays the  start of the thermals.  Once you 

> can start to feel any perceptible  turbulence from thermals, there is 

> no point in trying to record  performance data, as it won't be very 

> accurate.

>

> Even early in the morning, the wind speed and direction will  usually 

> change with altitude, and this affects the results.  You  can minimize 

> the errors induced by wind change with altitude by  doing two runs at 

> each climb speed, with the two runs on headings  that differ by 180 

> degrees.  The effect of wind on the two runs  will be in the opposite 

> sense, so if you average the rates of climb  you will mostly cancel 

> out the effects of this wind shear.

>

 

 One more thing - it may be more productive to delay detailed  

 performance testing until you are out of the flight test phase so you  

 can carry someone to record data.  It can be very difficult to  

 accurately fly the aircraft, keep a look out for traffic, and record  

 climb data.  If you try to do it all yourself, you probably won't  hold 

 airspeed as accurately as desired, which will make the results  

 inconsistent.  It is much easier if you can divide the tasks between  

 two people.  Just make sure you agree on which of you is in charge of  

 looking for traffic, or you might find that neither of you is doing it.

 

 For phase one flight testing, if I didn't have an automatic data  

 logger, I would probably just do very rudimentary performance tests.   

 Then once I could legally carry someone to record data I would do the  

 detailed performance testing.

 

 Fly safe,

 

 -- 

 Kevin Horton

 RV-8 (Finishing Kit)

 Ottawa, Canada

 http://www.kilohotel.com/rv8

-------------------------------------------------------------------------------------------

av8or(at)cox.net
Guest

Posted: Thu Mar 06, 2008 9:38 am Post subject: RV-7 Best climb and rate of climb

Try using a camcorder pointed at the panel and a  cable connection from your headset mic to the camcorder.  Then all you have  to do is talk and the information is recorded.

  

 John

 [quote]   ---

brad.reak(at)verigy.com
Guest

Posted: Mon Mar 10, 2008 1:01 pm Post subject: RV-7 Best climb and rate of climb

I have and RV7A with O360 180HP and the same Sensenich prop.  I just completed my testing a few weeks ago and here is a summary of what I did and learned.



1. Do testing early in the morning, my afternoon data was thrown out because I could never get the plane stabilized.

2. I live in Colorado at around 5000ft so had take my data from 7000ft to 8000ft.

3. Climbs were stated at about 6200ft to be stabilized by 7000ft.

4. Data was taken from 60kias to 110kias at 5kt increments, with a minimum of four runs in opposite directions.  As I learned more I took more data from 80 to 95kts.

5. The OAT varied from 5C to 8C over the test period (three mornings at the same time).

6. Plane, pilot and fuel averaged, 1525 lbs.

7. Testing always started with full fuel but fuel is burned during the test and I could only guess at the exact weight during a particular test.

8. Climb rate data from a particular airspeed was averaged.

9. Climb rate data was Graphed and Vx computed from the tangent to the best rate of climb as described in AC90-89A pages 47 and 48.



My result was:



Vy = 88KIAS

Vx = 72KIAS



Things I learned:



Wow, this was harder than I imagined.  When I look at my best rate of climb curve it is very flat from 80 to about 100kts but there is a small peak at 88kts.  The Vy data isn't very useful because climbing at 88kts produces a deck angle that is much too high to be safe, I cannot see over the nose and it's uncomfortable for pilot and passenger.  Also, I need to get the speed higher to achieve CHT under 400F on warm days.  In practice I find the 110kts is a better climb speed.



I've estimated my best glide speed to be 80KIAS.



Brad

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