Check them flaps stops...

[Vac]

The mighty RV-4 has manual flaps. Clever design with a simple aluminum bar connected to the flaps that locks into the side of the pilot's seat. There are some small, beveled blocks on the seat that hold the handle up (and keep flaps down) when the flaps are deployed. After a while (about 2000 hours, including lots of flap use for flight test), the bevel on the flaps 40 detent was pretty worn down. Warning, there is a bit of sporty language in the video:

https://youtu.be/R8VIUQTO-XU

It may be one of the few airplanes that has manual flaps and a flap position sensor. That sensor is part of the AOA system. If you have an AOA system, it's important that the system has an accurate calibration for each flap setting. If you watch the video closely, you'll see how the system responds when the flaps retract with a "bang" (momentary slow tone during the AOA excursion or "spike") The initial pitch-up is caused by the pitch trim change when the flaps retract uber fast. If you watch the "indexer" (military slang for the visual AOA display), you'll see that the trend indicator responds to the event (as well as the % lift indication), but it happens fast. Real fast. The tone does a better job of conveying the "slow" condition to the pilot.

Fly safe,

Vac

 

[ronrapp]

Wonder if the 6 has the same setup? I practice no-flap landings on occasion but have to admit I sometimes wonder why (aside from fun and variety). I mean, manual flaps can't fail... can they?

--Ron

 

[Marc DeGirolamo]

-6 flaps

Different setup for the -6.....they have a Johnson bar between the seats and the detents are down at the base of the bar.....vs on the seat of the -4. I have had mine pop every once in a while.....gets your attention for sure....

 

[gasman]

Different setup for the -6.....they have a Johnson bar between the seats and the detents are down at the base of the bar.....vs on the seat of the -4. I have had mine pop every once in a while.....gets your attention for sure....

Properly built and maintained, RV6 manual flaps have a very low failure rate.

 

[Scott Hersha]

Properly built and maintained, RV6 manual flaps have a very low failure rate.

Very low, agreed……. zero I would think.