Spycams and Hammerheads

[lluciani]

I bought a MD80 "Spycam" on eBay for $12 and mounted it on my RV8's wing tip. I made a small aluminum mount and screwed it in to the existing plate nuts. Here's a short movie I made a couple of months ago: http://www.youtube.com/watch?v=06tyP-Jj834.

The camera has enough battery to last about 1 hour. The micro SD Card I have is good for about 25 minutes of video. Since I have to start recording before starting the plane, there is barely enough time to get out to the practice area.

The hammerheads at the end of the video are not as vertical as I intended for them to be. They seemed fine when I was doing them.

On the subject of hammerheads, I have been doing them in my RV8 for about a year. I do them because there is a hammerhead in the IAC Sportsman sequence and because they are really a lot of fun.

I have never had a problem with hammerheads until a month ago. I did one where I unintentionally waited too long before starting the pivot. I think I was also pitched beyond vertical. When pressed down on the rudder pedal there was no resistance and the plane didn't respond. It stayed more or less vertical at full power and full left rudder for what seemed to be a couple of seconds. It then fell over on its back and started to rotate at the same time. As the nose passed through the horizon I chopped power and centered the controls and rudder. Slightly opposite rudder as the nose dropped down immediately stopped the rotation. I eased back on the stick to go vertical down and then pulled to level off.

I love doing hammerheads. Still, I will only do them wearing a parachute, at fwd CG (i.e. solo in my RV8) and with lots of recent spin practice.

[Snowflake]

I know that feeling about the rudder... It feels like the cable has become disconnected, right? Very disconcerting... I got that same feeling on the elevator, but I was doing a hamerhead too. I also left it a tiny bit too long before the pivot and fell out, but it fell forward onto it's belly. I pushed the nose down, then tried too soon to pull back and recover, and that same "disconnected" feeling came with the stick all the way to my lap. Had to center the stick again and wait for it to speed up a bit to get enough control authority to try again. Ah well. That's why we do these things at 4-5000' AGL when we're learning, right?

[WillyEyeBall]

Luis,
Nice video and write up with the hammerhead adventure. I especially noticed your beautiful RV-8 and went to your website for pictures and found your write-up on your first IAC contest: http://www.flugeron.com/fun/08312008.htm That's exactly the impression I had too, and hope other RVers will come join the fun.
Thanks,
Bill McLean
RV-4 Slider

[lluciani]

Thanks Bill.

Does anyone know of a good technique for picking the right time to start the pivot? I have been using my airspeed indicator (30kts) but this is hard to do while looking at the wing tip. I have also tried yarn on the wing tip with no success. It doesn't seem to do anything different on the way down to 30kts.

[frankh]

30kts works good on the 7.

If you had held the control inputs ypu might have done an inverted spin..As me how I know...

Frank

[hendrik]

No experience in power planes. In the glider I look at the wing tip and start the pivot when the wind noise sounds about right. I never look at the ASI for that. Once I started the pivot, I keep my eyes at the horizon to check how much opposite aileron I need to keep the plane from rolling on its back (long wing span -> upper wing produces much more lift). When I'm almost through the turn I look straight down and check if I need to cheat and change the direction by a bit of roll during the vertical.

In a glider starting the pivot too early has a very similar effect to starting it too late. If I start too late, I'm too slow to make it all the way round, and the plane starts falling down sidewards until the nose drops down. If I start too early, the plane side-slips upwards, the tail acts as a vane preventing the plane from turning, I lose lots of energy until the plane is too slow and starts falling down sidewards.

If there is any danger of sliding backwards, don't let the controls go. You don't want them being banged into the stops by the reversed air flow.

[tadsargent]

FrankH 30 Knots is too slow for my 7A

lluciani, if your add right rudder as the nose passes the horizion in the kick, you'll avoid the nose reacting like a pendelum on the down line.

Nice video

Stripes

[rjtjrt]

lluciani
I am reluctant to post an opinion as I am no expert when it comes to aerobatics.
However, here goes.
You appear to be describing a late rudder application with possibly an incipient Tail Slide.
A Tail Slide is a potentially dangerous as it can produce structural damage to control surfaces, especially if not handled correctly. Very bad to have elevator, or rudder, or aileron deflected even a little whilst airflow reversed. Must centralise all conrols and hold them rigidly centralised until aircraft is out of Tail Slide. I suggest you read further on this in any of the good aerobatics books, or speak to a qualified aerobatics instructor.
Secondly, as FrankH said, not hard to get into an inverted spin if a stall turn goes wrong. On upline, especially if over do the inittial pich line and tryintg to correct, if slow at top with slightly forward stick, as you "kick" rudder at top , have perfect set up fpr inverted spin (below stall, wing dropping, forward stick). It can happen fast and be VERY disorienting as unexpected and inverted spin is odd feeling and visually.
Again I suggest you speak to a qualified aerobatics instructor about both how to handle an inadvertent Tail Slide, and inverted spinning.
Best wishes
John

[ronschreck]

Luis,

Don't let the "experts" get you down. If someone on this forum has ever experienced an inverted spin in a RV, please chime in here. And if someone has by some stroke of luck, skill or genious entered an inverted spin and was unable to get out of it by simultaneously scratching their behind and picking their schnozola, please let us know.

I have spent hours trying to get my RV to spin better and the "experts" keep telling me that I might accidently succeed. I wish!

[rjtjrt]

Ron
As I said I don't claim to be an expert.
Definitely not trying to frighten anyone - aero's are fun and any pilot can do them safely if trained/knowledgeable, but there are some traps.
RV's aren't unique in aerodynamic terms.

However you are correct in one thing - most aircraft inehently want to come out of an inverted spin so recovery by Beggs method is easy.

John