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Aerobatics and the Whirlwind 200RV prop

izzybear

izzybear

Well Known Member
Friend
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? :eek:
 
My old pal "PChunt" here on the forums has one on his -6. Hopefully he can chime in or you could PM him.
 
"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!
 
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
 
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.
 
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?
 
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.
 
scsmith said:
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.
Click to expand...

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.
 
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!
 
Also note that Whirl Wind will build a 200RV prop with counterweights if you ask them to. They don't advertise it per se, but they have told me they'll do it if I ask for it. Same applies to the 74RV. Costs and weighs a little more, of course. Calling and speaking with them is time well-spent.
 
I've got a Whirlwind CS on my 8. Called the company. They said Gentlemen's acro was fine. Do them all the time including the cuban 8's. No problems.
 
In addition to oil pressure loss issues, aerobatic props are also designed to withstand snap roll and tumble maneuvers which put high gyroscopic stress on the blades and hub. If you're not doing those or any maneuvering that causes significant, extended oil pressure loss, there is nothing to worry about with a non-acro prop. Virtually all RVs see nothing but simple positive G loops and rolls. Like Smokey says, pull the throttle back if you happen to hear a surge.
 
luddite42 said:
In addition to oil pressure loss issues, aerobatic props are also designed to withstand snap roll and tumble maneuvers which put high gyroscopic stress on the blades and hub. If you're not doing those or any maneuvering that causes significant, extended oil pressure loss, there is nothing to worry about with a non-acro prop. Virtually all RVs see nothing but simple positive G loops and rolls. Like Smokey says, pull the throttle back if you happen to hear a surge.
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I wouldn't even worry about high gyroscopic stress on any composite prop. The blades are very light, compared to metal blades of the same size and the hubs are generally the same for metal and composite blades. Now, having said that, I recall that Whirlwind has taken some metal off of their hubs and this is possible because of the smaller loads imposed by lighter blades. Never heard of a hub failure due to aerobatics. Anyone?
 
ronschreck said:
I wouldn't even worry about high gyroscopic stress on any composite prop. The blades are very light, compared to metal blades of the same size and the hubs are generally the same for metal and composite blades. Now, having said that, I recall that Whirlwind has taken some metal off of their hubs and this is possible because of the smaller loads imposed by lighter blades. Never heard of a hub failure due to aerobatics. Anyone?
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In the past 10 years I know of around seven Whirlwind acro prop failures - 150/151 and 200C. Thrown counterweights, thrown blades. Not sure the failure mode of all of them. All were flown beyond "gentlemen's acro". Not sure if the actual hub failed, but Hartzell has had aerobatic hub cracking in the past with metal blades. Fixed now. None of this should concern anyone here.
 
They're fine

Flew my 7 over 800 hours and did lots of aerobatics. No issues at all. Most all positive but would occasionally pause inverted during a 4 or 8 point roll.

The failures were the early 151's and 200C's. Some being pushed pretty hard. The new blade, according to WW, is for 200 hp or more. No advantage over the 200RV if used on lower HP engine. The only thing lower will be your wallet:eek:
 
Props

luddite42 said:
In the past 10 years I know of around seven Whirlwind acro prop failures - 150/151 and 200C. Thrown counterweights, thrown blades. Not sure the failure mode of all of them. All were flown beyond "gentlemen's acro". Not sure if the actual hub failed, but Hartzell has had aerobatic hub cracking in the past with metal blades. Fixed now. None of this should concern anyone here.
Click to expand...

How many failures over the years on MT's??? I would venture far more than Whirlwind. I had a failure years ago on a three blade MT that was not reported.
The early Hoffman aerobatic constant speeds failed to flat pitch with loss of governor pressure.
If installed in EAB, 4000 r/m does not mean the engine is trashed. The parallel valve 360's have thousands of hours of operation in the 35-3600 r/m range. They will likely tolerate one overspeed to 4000 r/m. The angle valve engines are not quite as tolerant of high r/m but still survive in the 3500 r/m range. The Red Devils/Christen Eagles Airshow Team used fixed pitch props because they wanted to make noise. 25 years operating in the 3500 r/m range. Hilliard's Pitts was always angle valve 360. I can pretty well tell what the r/m is on a 75" diameter prop just by the sound. They start to make a lot of noise above 3000 r/m and a LOT of noise at 3500 r/m.
 
Thanks for your input!

Thanks everyone for your input - I really appreciate it. I now have a better understanding of the advantages and disadvantages of the non-aerobatic prop and specifically, the 200RV. Thanks also for the extra ideas as I move - more confidently in the direction of my decision. :)
 
It'll do great

I have inverted fuel and oil and a dual seat-belt with ratchet in my -8. The 200RV does great during aerobatics.

 
jrs14855 said:
How many failures over the years on MT's??? I would venture far more than Whirlwind. I had a failure years ago on a three blade MT that was not reported.
The early Hoffman aerobatic constant speeds failed to flat pitch with loss of governor pressure.
If installed in EAB, 4000 r/m does not mean the engine is trashed. The parallel valve 360's have thousands of hours of operation in the 35-3600 r/m range. They will likely tolerate one overspeed to 4000 r/m. The angle valve engines are not quite as tolerant of high r/m but still survive in the 3500 r/m range. The Red Devils/Christen Eagles Airshow Team used fixed pitch props because they wanted to make noise. 25 years operating in the 3500 r/m range. Hilliard's Pitts was always angle valve 360. I can pretty well tell what the r/m is on a 75" diameter prop just by the sound. They start to make a lot of noise above 3000 r/m and a LOT of noise at 3500 r/m.
Click to expand...

I'm going to venture a guess that those thousands of hours have overhauls between them. The aero engines I used above 3500rpm rarely had more than 50 hours on them between disassembly and inspection. Same with the props, a 4000 rpm rapid acceleration will most likely stretch the connecting rods beyond limits. This kind of event is very different from a fixed pitch prop turning at 3500 RPM. Robinson helicopters has experience with a lot of these in botched starts with the throttle opened too far.

My favorite event was Reno with the TIO-540 that went flat pitch/closed wastegate all at the same time. That was in excess of 8000rpm before the engine seized. The Hartzell retained all 3 aluminum blades, but both the prop and engine were really trash. Stretched the prop mounting studs 1/8" or so if I remember correctly.
 
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