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  #1  
Old 02-27-2019, 07:57 PM
AlanTN AlanTN is offline
 
Join Date: Apr 2011
Location: Linden, TN
Posts: 79
Default Updated Range Numbers

In August of 2017 I started a thread with questions about the RV-12/RV-12iS range numbers. One of the questions I asked was how with the RV-12iS at 5500 RPM and 7500 ft, the range could be 630 miles, while at 5000 RPM and 7500 ft, it was only 605 miles. It just didn't seem likely to me that at a higher speed the range would be farther. Those numbers still exist in the current RV-12/RV-12iS brochure on Van's website should anyone wish to verify that.

However, I see that they have now posted in the performance section on the webpage some new numbers that make much more sense to my engineering mind. They are as follows: At 5500 RPM and 7500 ft the range is listed as 528 miles, and at 5500 RPM and 7500 ft the range is listed as 631 miles.

These new numbers are in line with what I would expect, and I am pleased to see the update. As I stated before, I am very impressed the the current design of the RV-12iS and with the quality of Van's aircraft kits.
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  #2  
Old 02-27-2019, 08:17 PM
rongawer rongawer is offline
 
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Location: Brentwood, CA
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The 528 and 631 numbers agree with the 459nm and 549nm ranges listed in the updated POH. It’s important to note that both of these ranges are listed as “no reserve”.

I was a little disappointed to not see the ranges even longer as has been described in other threads, upwards of 30% stated by some. And that the listed 5500 rpm range for the ULS is longer than for the iS; both are no reserve numbers, so I’m interested to know if that’s accurate.
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Last edited by rongawer : 02-27-2019 at 08:37 PM.
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  #3  
Old 02-27-2019, 09:56 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by rongawer View Post
The 528 and 631 numbers agree with the 459nm and 549nm ranges listed in the updated POH. Itís important to note that both of these ranges are listed as ďno reserveĒ.

I was a little disappointed to not see the ranges even longer as has been described in other threads, upwards of 30% stated by some. And that the listed 5500 rpm range for the ULS is longer than for the iS; both are no reserve numbers, so Iím interested to know if thatís accurate.
I think you misread the ULS #'s.......
The 5500 RPM range for the ULS is 433 sm, which is far less than the 528 sm listed for the iS.
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  #4  
Old 02-28-2019, 08:25 AM
rongawer rongawer is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
I think you misread the ULS #'s.......
The 5500 RPM range for the ULS is 433 sm, which is far less than the 528 sm listed for the iS.
No, I didn't misread it. POH revision 3, section 1.2 clearly shows "nm" after the ranges listed along with an asterisk noting "No allowance for takeoff, climb, descent or reserve".

If that is an editing error, ok. You might go check it, however both the ULS and iS ranges are listed as 'nm'.
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- RV10, N1530G (reserved). Build in progress.
- RV12, N975G, "The Commuter"
- Several others that are now just great memories for me.
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  #5  
Old 02-28-2019, 08:32 AM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by rongawer View Post
No, I didn't misread it. POH revision 3, section 1.2 clearly shows "nm" after the ranges listed along with an asterisk noting "No allowance for takeoff, climb, descent or reserve".

If that is an editing error, ok. You might go check it, however both the ULS and iS ranges are listed as 'nm'.
Ok, it was I that read incorrectly. I didn't see that you said POH
The numbers that I posted (ULS is 433 sm, and iS is 528 sm)are what are on the web site and I believe they are correct.
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  #6  
Old 02-28-2019, 11:50 AM
NinerBikes NinerBikes is offline
 
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So, in the interest of brevity, are we talking in nautical miles or statute miles, for both the ULS and IS motor versions, on the webpage. Which unit of measure is correct?
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  #7  
Old 02-28-2019, 12:22 PM
AlanTN AlanTN is offline
 
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The current range numbers on Van's website appear to consistently be shown in statute miles.

The new numbers for the RV-12iS make sense to me.

But, what still mystifies me is how the range of the standard RV-12 could be nearly the same at 120 mph (435 miles) as at 136 mph (433 miles). That doesn't seem likely considering that drag increases as the square of velocity.

Another point is that if you compare 435 miles for the RV-12 and 631 miles for the RV-12iS, both at 7500 ft and 5000 rpm, the range of the RV-12iS would be 45% longer (631/435-1)*100 = 45%.

Based upon tests done by Rotax, I think 30% improvement is likely, but not 45%. Because this is larger than normal experimental error of perhaps 2%, one or both of these numbers may be suspect.

Disclaimer: This is only my opinion and of course I could be mistaken!
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Last edited by AlanTN : 02-28-2019 at 12:43 PM.
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  #8  
Old 02-28-2019, 03:32 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by AlanTN View Post
The current range numbers on Van's website appear to consistently be shown in statute miles.

The new numbers for the RV-12iS make sense to me.

But, what still mystifies me is how the range of the standard RV-12 could be nearly the same at 120 mph (435 miles) as at 136 mph (433 miles). That doesn't seem likely considering that drag increases as the square of velocity.

Another point is that if you compare 435 miles for the RV-12 and 631 miles for the RV-12iS, both at 7500 ft and 5000 rpm, the range of the RV-12iS would be 45% longer (631/435-1)*100 = 45%.

Based upon tests done by Rotax, I think 30% improvement is likely, but not 45%. Because this is larger than normal experimental error of perhaps 2%, one or both of these numbers may be suspect.

Disclaimer: This is only my opinion and of course I could be mistaken!
Typos are not mystery's, they are caused by less than perfect humans.
I imagine there is still one (if not more) in the RV-12 data so it will be looked at.
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Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #9  
Old 02-28-2019, 03:34 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by NinerBikes View Post
So, in the interest of brevity, are we talking in nautical miles or statute miles, for both the ULS and IS motor versions, on the webpage. Which unit of measure is correct?
All of the range distance values on the web site have sm after them so the intent is for them to be Statute Miles.
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RV-6A (aka "Junkyard Special ")
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  #10  
Old 02-28-2019, 04:19 PM
AlanTN AlanTN is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
Typos are not mystery's, they are caused by less than perfect humans.
I imagine there is still one (if not more) in the RV-12 data so it will be looked at.
Thanks, Scott. That was what I was hoping for.
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