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200RV Prop - Aerobatics
- Thread starter gciampa
- Start date
ronschreck
Well Known Member
Two of the five aerobatic qualified pilots on Team RV fly with the Whirlwind 200RV propeller. Two have Hartzells. The fifth flies an RV-4 with a fixed pitch prop... and if he doesn't switch to a CS soon we're going to spin the pistons right out of his engine! He is afraid to even look at his RPM any more. Is the 200RV suitable for light aerobatics? Check out our video and judge for yourself.
200RV is not an "aerobatic" prop
Though the Whirlwind 200RV is fine for "gentleman's" aerobatics, it is not an aerobatic prop. The operational difference of an aerobatic prop is how it reacts to oil pressure. A non-aerobatic prop such as the 200RV goes to fine pitch High RPM) with the loss of oil pressure. AN aerobatic prop uses a counterweight system to do the opposite.
The purpose of this is to minimize engine surging and not overspeed the engine with a momentary drop in oil pressure. Even with an inverted oil system, as you transfer from positive to negative "G", there is a momentary loss of oil pressure. If you are at a high RPM at the time, you risk over speeding the engine during this transition. The aerobatic prop will prevent this.
For positive "G" aerobatics, the standard prop is fine. It will also perform fine if you keep the power low during this transition from positive to negative flight so that the prop does not have time to overspeed the engine.
If you fly competition style aerobatics, even at the Sportsman level, you will want the protection of the aerobatic prop.
Scott A. Jordan
N733JJ
Though the Whirlwind 200RV is fine for "gentleman's" aerobatics, it is not an aerobatic prop. The operational difference of an aerobatic prop is how it reacts to oil pressure. A non-aerobatic prop such as the 200RV goes to fine pitch High RPM) with the loss of oil pressure. AN aerobatic prop uses a counterweight system to do the opposite.
The purpose of this is to minimize engine surging and not overspeed the engine with a momentary drop in oil pressure. Even with an inverted oil system, as you transfer from positive to negative "G", there is a momentary loss of oil pressure. If you are at a high RPM at the time, you risk over speeding the engine during this transition. The aerobatic prop will prevent this.
For positive "G" aerobatics, the standard prop is fine. It will also perform fine if you keep the power low during this transition from positive to negative flight so that the prop does not have time to overspeed the engine.
If you fly competition style aerobatics, even at the Sportsman level, you will want the protection of the aerobatic prop.
Scott A. Jordan
N733JJ
Ok, now you guys are just showing off....gee thanks, now in addition to the prop I need to add smoke....
Oh well..so much for the anniversary vacation!
Grazie
ronschreck
Well Known Member
Scott,
Everything you said is essentially correct. Let me add some personnal experience: I flew the 200RV for 600 hours before I installed an inverted oil system on my RV-8. I did several aerobatic maneuvers that cause a momentary loss of oil pressure (2-3 seconds maybe) and this never caused the prop to go to low pitch. I was concerned, however that these short periods of zero oil pressure could be detrimental to engine longevity so I installed a "half-Raven" inverted oil system with an oil accumulator that will give me about seven seconds of pressure if normal pump pressure falls off. I do compete at the sportsman level with the 200RV prop and have had no issues. Even without the modified oil system I would not hesitate to say that the 200RV is perfectly capable of performing well at the sportsman level. Would I like an aerobatic prop? Maybe. But I'm not sure I want to give up the top end speed that the 200RV provides.
Well - even thats not always strictly true - have a look at the Hartzell Claw - it uses oil pressure to increase pitch and its definitely an aerobatic prop!
I may be abandoning my aerobatic Hartzell in the near future. It will be replaced with a blended airfoil or a 200RV with the accumulator. Glad to hear that setup works.
Scott A. Jordan
N733JJ
890 hours
