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06-30-2015, 03:22 PM
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Join Date: Sep 2010
Location: Dallas, TX
Posts: 330
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Aerobatics and the Whirlwind 200RV prop
I was wondering if those of you who have experience flying behind the Whirlwind Aviation 200RV propeller, could tell me about your experience with this prop as it relates to aerobatics. Reading from the owner?s manual ? section 2.3 starts with, ?This 200RV Series propeller is a standard, non-aerobatic hydraulically controlled propeller system.? Yet, I spoke to someone at Whirlwind and specifically asked them about the owner?s manual statement in section 2.3 and they replied with, ?This propeller is an excellent choice for cruising long distances and for light gentlemen's aerobatics (positive "G" maneuvers).? So I am interested in what the user's have to say. I am looking to do some periodic gentleman's aerobatics and want to make sure I am getting the right prop for it...and what happens if I accidentally do a negative "G" maneuver? 
__________________
Jim
RV-8 N223GT (reserved)
Finish - arrived 10/7/15
Fuselage - arrived 3/14/14
Wings - arrived 3/7/13
Builder # 83331
www.mykitlog.com/izzybear
VAF Dues gladly paid up till December 2020
"The ultimate responsibility of the pilot is to fulfill the dreams of the countless millions of earthbound ancestors who could only stare skyward and wish." - Unknown
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06-30-2015, 03:36 PM
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Join Date: Apr 2012
Location: West Fargo, ND
Posts: 1,073
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My old pal "PChunt" here on the forums has one on his -6. Hopefully he can chime in or you could PM him.
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Derek Hoeschen
EAA Tech Counselor
RV-9A #92103 - N803DK
G3X, Superior XO-320, Dual Pmags, Catto 3B
www.mykitlog.com/dbro172/
1974 Bellanca Super Viking - N16AW - Flying
RV-8 #83565 - N184DK - building
1968 Mooney M20C - N6801N - Sold
1956 C-182 - N744W - Sold
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06-30-2015, 03:44 PM
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Join Date: Jan 2008
Location: Atlanta, GA
Posts: 240
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"non-aerobatic" in this case refers to the fact that it's a normal, pressure to increase pitch, constant-speed prop. This means that high pressure from the governor will increase the pitch, which decreases the rpm. The significance of this is that in the case of a loss of oil pressure, the prop will go to fine pitch, high rpm, which gives you essentially go-around power.
"aerobatic" props have counterweighted blades. The counterweights try to keep the prop in high-pitch, low-rpm operation, and they are pressure-to-decrease-pitch. In the event of a loss of oil pressure, they go to high pitch, low speed. This is desirable for hard aerobatics, because if you unport your oil pickup in a dive, and the prop goes flat, you can easily overspeed your engine.
No reason you can't do aerobatics with a non-counterweighted prop. Hopefully this makes the differences more apparent to you!
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Ian
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06-30-2015, 03:51 PM
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Join Date: Jun 2005
Location: San Jose, CA
Posts: 78
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If you go negative for long enough to loose oil pressure a standard CS prop will go to low pitch/high RPM. When an aerobatic/counter weighted prop loose oil pressure it goes to high pitch/low RPM. On an inverted down line, with a standard CS prop, you could loose oil pressure and over speed your engine.
Brian
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Brian Dal Porto
RV-7 Tipper
IO-360A3B6D
Whirl Wind 200RV
Dynon Skyview Touch
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06-30-2015, 04:57 PM
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Join Date: Dec 2009
Location: Montreal
Posts: 1,456
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I know a guy (rver) who did unport his oil pickup and he went close to 4000 rpm. Scrap one engine and prop. But he was doing something out of the ordinary. so it is not a wife's tail.
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Scott Black
Old school simple VFR RV 4, O-320, wood prop, MGL iEfis Lite
VAF dues 2020
Instagram @sblack2154
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06-30-2015, 05:40 PM
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Join Date: Sep 2010
Location: Dallas, TX
Posts: 330
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so it's more about the failure mode
Thanks Derek, Ian, Brian and Scott... (I will pm PChunt) I did read in the manual about the failure mode going to high rpm/flat pitch and the warning that you could over-speed the engine if you did not close the throttle quickly. So, all other things being equal - is one prop as good for aerobatics as another, until/unless it fails and then the aerobatic prop will fail to low rpm (good) where the non-aerobatic will fail to high rpm (bad).
Other than Scott's example where, "he was doing something out of the ordinary", would a non-aerobatic prop be more apt to fail doing occasional, light aerobatics? Has anyone had any problem with their 200RV during or after aerobatics? I guess I am trying to figure out if it is just about the failure mode, or - Is it like doing off road driving in a jeep vs. a smart car - one won't be able to handle the strain nearly as well as the other?
__________________
Jim
RV-8 N223GT (reserved)
Finish - arrived 10/7/15
Fuselage - arrived 3/14/14
Wings - arrived 3/7/13
Builder # 83331
www.mykitlog.com/izzybear
VAF Dues gladly paid up till December 2020
"The ultimate responsibility of the pilot is to fulfill the dreams of the countless millions of earthbound ancestors who could only stare skyward and wish." - Unknown
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06-30-2015, 06:08 PM
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Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,574
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mild aerobatics with WW 200RV prop
I do mild aerobatics with my Whirl Wind 200RV prop. I try to stay slightly positive G.
I have not experimented with completely unloading the airplane for more than just an instant. The only drawback to maintaining slightly positive G is that rolling to finish a cuban eight takes me off track a bit. It might be that I could fully unload for the brief time needed to roll out, but I have not really tried it.
Also, for typical RV entry speeds, you end up being pretty well throttled back anyway, so there is some margin for overspeed. I don't recall exactly, but something like 2300 rpm and 21" MAP will get you around 140 kt IAS entry speeds. With the throttle closed that far, it would take a bit of diving to get the RPM up too high.
I'd be curious to know if others with C/S props adjust throttle at various parts of a maneuver. Certainly it would give way bigger loops and barrel rolls to go full throttle in the climb and retard the throttle as you go over the top. I just set it for level entry speed an leave it.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 625
LS6-15/18W sailplane SOLD
bought my old LS6-A back!! 
VAF donation Jan 2020
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06-30-2015, 07:20 PM
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Join Date: Feb 2007
Location: San Diego, CA
Posts: 1,670
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PM sent to "Izzybear" 
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Pete Hunt, [San Diego] VAF #1069
RV-6, RV-6A, T-6G
ATP, CFII, A&P
2020 Donation+, Gladly Sent
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06-30-2015, 08:35 PM
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Join Date: Mar 2010
Location: USA
Posts: 454
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Quote:
Originally Posted by scsmith
The only drawback to maintaining slightly positive G is that rolling to finish a cuban eight takes me off track a bit. It might be that I could fully unload for the brief time needed to roll out, but I have not really tried it.
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You can stay on heading just fine without unloading to zero or negative - just apply a little opposite rudder with the aileron input, then switch to same side rudder for the second half of the roll to upright.
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07-01-2015, 04:56 AM
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Join Date: Mar 2006
Location: Gilbert, AZ
Posts: 1,628
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I flew with a 200RV for over 1500 hours before installing a Hartzell composite prop when Hartzell became a Team AeroDynamix sponsor. I loved the 200RV and did heavy aerobatics with it. In competition aerobatics I fly with the throttle full forward during all maneuvers except spins. Any non-aerobatic prop will go to low pitch with a sustained loss of oil pressure but rapid closing of the throttle will keep RPM within safe limits. The 200RV is a great prop and performs as well as any during aerobatic flight. Go for it!
__________________
Ron Schreck
IAC National Judge
RV-8, "Miss Izzy", 2250 Hours - Sold
VAF 2021 Donor
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