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Old 09-25-2019, 10:23 AM
scottmillhouse's Avatar
scottmillhouse scottmillhouse is online now
Join Date: Apr 2007
Location: Madison, AL
Posts: 336

On my 12 for one flight I was way over pitched at 3000' on a 50 degree day with 1/2 fuel and a 170# pilot and could hold 128+ knots TAS at about 6.5 gph. Climb performance was anemic and almost impossible to maintain above 5200 rpm in climb out. Reduced pitch some and flew awhile with 124 knot cruise but found climb performance to suffer too much with hot weather and when at full gross. Tried a few more settings ending back at Van's recommendations for all around use.
Scott- 2020 donation
New RV-7A N579RV, only 70 hours now without 2020 fly-in destinations
Built RV-12, 328 hours-sold, purchased RV-12 sold, Built RV-9A, 536 hours-sold, Not completed RV-7 sold, Built Kitfox sold
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Old 09-25-2019, 10:26 AM
NORM T NORM T is offline
Join Date: Feb 2019
Location: Dallas, OR
Posts: 17

Originally Posted by NinerBikes View Post
Assuming you have 750 # bird and 60# of fuel on board, how close are you to being the mythical 225 # pilot in command? If you climb at Vx and 75 kts, what do you get for rpm readings then, since you would be 200 -275# under max gross of 1320# ? My friend, Bob, weighs 225 and with full fuel in a 753# bird, starting at 1040 ft ASL, he says that in all seasons except summer, he sees about an indicated climb rate of 1300 fpm, here in So California.
I don't know, I've never flown at max gross weight. Maybe I will check my rate of climb someday. I am happy with whatever it is.
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Old 09-25-2019, 02:49 PM
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rvbuilder2002 rvbuilder2002 is offline
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,906

Originally Posted by NORM T View Post
Hey guys, my data was just that, data, not a controlled test and obviously not repeatable. I am sorry if my numbers upset people I simply flew it on an early spring day to find my comfort zone regarding engine rpm and fuel burn. The airplane is a 2015 with the 912 ULS that I purchased flying with 18 hrs on the meter, in 2017. Flying with whatever the conditions were that day, autopilot on straight and level, with me and a maybe a half tank of non-ethanol premium mogas, much less than max gross weight, about 3000 ft msl, 2800 agl, noted the Dynon readings for what I believed were steady state for IAS in kts, fuel gph and RPM. The data indicated to me that I could comfortably cruise at about 5200 RPM with best MPG, but above that the fuel economy goes down rapidly. Flying at slower RPM resulted in data that indicated less MPG, but more hours flight time per gallon for just flying around. As for absolute values for airspeed and fuel burn, I can't control them except with throttle setting in level flight, they are whatever they are, and I accept that. I do not know the prop pitch, but I see about 5200 RPM in full power climb at about 80 kts and maybe 1000 fpm. Full power in level flight will rapidly exceed redline RPM. This is when flying near sea level.

I did not intend to stir the pot nor try for bragging rights. I think my RV-12 does what Van says it does. I like it a lot.
I didn?t mean to offend with my post.
I was just trying to point out that a little bit of data that only tells a small piece of a story doesn?t really provide any useful info. I don?t mean to offend again by saying that but it is true. With an adjustable fixed pitch prop., it is possible to set the prop so that a specific performance perameter is fantastic, but all other #?s will be abysmal. I can say from experience from literally hundreds of hrs of flight testing it is not possible to get 127 Kts TAS at 5500 RPM at 5 GPH and still have normal climb performance.
I?m not saying you didn?t see this numbers..... just saying that there has to be some other influences ( you were looking at ground speed instead of TAS, the prop pitch was way off to where climb would be severely effected, etc.).

Point being, the performance #?s posted on the web site are real and valid and we?re attained after hundreds of hours of very detailed flight testing, and if anyone thinks they are getting #?s that are different by very much, it is likely because of an inaccuracy in the data or some adjustment that will be effecting a different perameter in a negative way.
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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Old 09-26-2019, 01:32 PM
NORM T NORM T is offline
Join Date: Feb 2019
Location: Dallas, OR
Posts: 17

Scott, my post of some flight data was in response to questions regarding fuel burn experience and I am sorry I included my indicated air speeds. A lightly loaded 12 flying one time in rather ideal conditions, including high density atmosphere, and noting indicated air speed without regard for wind speed or direction as well as using rather short term Dynon readings is not my definition of controlled test results, just interesting data. I hope everyone knew that fact.

As to propeller pitch, airmen have been arguing over the merits and faults of Cruise Props vs Climb Props vs Constant Speed Props for at least most of my years on this earth. One of the features of our experimental world is the option to customize our aircraft to suit our needs and normal flying conditions, with respect for limitations. Flying my lightly loaded 12 here in the relatively open, unobstructed area in the Northwest and near sea level is obviously not universal conditions. By the way, I am slightly under 200 lbs, my 12 weighs less than 770 lbs and suits my needs and wishes quite well. I certainly agree, pilots should be quite aware of the ill effects of "lugging" an engine at full throttle, especially below peak torque RPM, and the need to care for temperatures and oil pressure. I think I am a conservative pilot and try not to push the envelope. I chose the way my 12 is fitted and try fly it accordingly. Maybe Van's designed it just for me, I like it! Thanks for listening.
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Old 09-26-2019, 02:20 PM
Piper J3's Avatar
Piper J3 Piper J3 is offline
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 1,949

Originally Posted by NORM T View Post
noting indicated air speed without regard for wind speed or direction as well as using rather short term Dynon readings is not my definition of controlled test results, just interesting data.
I don't understand what you're eluding to... air speed, Indicated or True, is entirely independent of wind speed or direction. Wind speed or direction has nothing to do with aircraft performance as it is operating in, and relative to, a moving air mass.
Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 585

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
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Old 09-26-2019, 07:28 PM
NORM T NORM T is offline
Join Date: Feb 2019
Location: Dallas, OR
Posts: 17
Default re: RV-12 Performance

[quote=Piper J3;1376159]I don't understand what you're eluding to...

Sorry I tried to contribute from my experience, apparently wasn't helpful. I still think that the 12 does what Van's says it does. Yes, I like it!
Norm out.
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