[Moon Doggie]

Has anyone experienced a sort of rhythmic hoping, jumping or bouncing like flight characteristic? I've had this happen three times over the past year (RV-7A,140 hrs total time). The most recent occurred just after leveling off at 5,000' and reducing the throttle to approximately 18"mp,with the prop still set at 2500 rpm from the climb. I estimate the frequency of bounces to be approximately 3/second. After reapplying power slowly, the bouncing dissipated to smooth flight. The stick doesn't appear to move during these episodes. Also, with someone holding the elevator on the ground, fore and aft stick play isn't more than 1/4". I don't know if there is a connection, but all three of these events occurred after painting (80hrs ago) when all control surfaces were R&R'd. One suggestion from Van's was the MT prop governor. They said there were some with problems when mine was issued. What do you folks think?

 

[Neal@F14]

Got a slider canopy?

We experienced a strange rhythmic vibration in the RV-8 in flight which was felt thru the whole airframe and that was affected by holding the rudder to one side or the other out of the ball's center. Turned out to be the rear of the slider canopy skirt vibrating against the turtledeck due to the propwash over the canopy. Putting some soft rubber weatherstripping under the canopy skirt to dampen/cushion it from the aluminum turtledeck skin stoppped the vibration completely.

 

[Moon Doggie]

Got a slider canopy?

We experienced a strange rhythmic vibration in the RV-8 in flight which was felt thru the whole airframe and that was affected by holding the rudder to one side or the other out of the ball's center. Turned out to be the rear of the slider canopy skirt vibrating against the turtledeck due to the propwash over the canopy. Putting some soft rubber weatherstripping under the canopy skirt to dampen/cushion it from the aluminum turtledeck skin stoppped the vibration completely.

No, it's a tip up, but thanks for your input. I don't recall the speed this happens at, but it's not at high speed. I believe closer to 110 to 120kts. Maybe it has something to do with AOA, but I don't think so.

 

[pierre smith]

Hit your brakes!

A friend of mine felt this rhythmic "bouncing" on a new -7, at cruise....sometimes. I suggested that the next time it happens, hit the brakes. He did and it stopped. Unfortunately, it started again, on a later flight. This time he hit one brake first and it stopped, so he knew which side was rotating. Even after the wheels are balanced, it would be nice to have enough friction to stop them from rotating in flight but how to do that?

Best,

 

[F1R]

Tighten your axle/ bearing nuts so that they take some hand pressure to rotate them. They should not quite rotate freely.