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Spin testing my RV-8

WA85

Well Known Member
During Phase 1, I did several stall series with pro-spin inputs, but never let the acft depart into a spin until such time as I had total faith in myself and my RV-8. After 135 hrs and about a year of flying it, I decided I was ready to start working my way into fully developed spins.
There are several excellent posts on VAF about RV spin techniques and in particular there have been some excellent posts about the unique characteristics of the RV-8. The British spin test of the RV-8 is an excellent resource on spinning the RV-8 in various CG configurations. Despite all this great information, I still had go spin test my RV-8, particularly in its as built configuration (IO-320, Catto FP Prop, 1028Lbs empty, Dynon SV). I built it light and it is light on the nose while flying solo, but it has excellent handling qualities, especially in pitch.
After reading all I could on VAF about RV-8 spin testing, I next went and attended a spinning training course with Catherine Cavegnaro at ACE Aerobatics in Sewanee TN. Catherine is an excellent instructor and will teach all you ever wanted to know about spins. She uses a C-152 Aerobat and we did all the spin entries from a full power on aggravated stall, which made for some nice and exciting spins and you get to do the full PARE recovery. After becoming comfortable with spins and various recovery techniques, I decided which one I would use for my first ever spin in my RV-8. I chose the idle power, neutral aileron, 1G wings level entry with full LH rudder applied at the break. I did check to see if the my original clean stall configuration produced the same results, which it did, just a wings level buffet and slight pitch down of the nose with an immediate recovery with fwd pitch.
For my first spin test, I set my CG at 80.56 and wt at 1485 lbs.
So for the first spin, I drank a bottle of liquid courage (Mountain Dew) and climbed to 7000 AGL in an approved area near a safe airport. My first spin entry was done by slowing to 65 KIAS in a slight pitch up and then briskly pulling the stick to the aft stop and applying full left rudder. As has been reported by others, as the acft started to depart off into a spin to the left, the acft pitch up and down 3 times for about 3/4 of rotation, then departed into a nice tight spin. Rotation didn't seem as fast as what I experienced in the C-152 will full power, but its fast enough. After two turns I applied opposite rudder and moved the stick to just under the cross bar, recovery was nearly immediate with an easy 2.5 G pull out. I lost about 800 feet, but my technique was not precise. I did a few more LH spins using variations of pitch and rudder inputs, to just relaxing the pro-spin inputs, which after 2 turns took about 1/2 turn to recover and about 1000 feet was lost with a 2 G pull out. Again, less altitude could be lost with better technique.
Overall what did I learn; The PARE technique seems to work just fine with a fwd CG. Prompt and simultaneous opposite rudder and fwd pitch was the quickest recovery. At FWD CG and idle power, my RV-8 does not seem to want enter into a spin unless you firmly apply and hold pro-spin inputs and allow the acft to depart. I could stop the spin entry in the first 1/2 turn by just releasing the aft pitch and relaxing the rudder input. I was a bit worried that my engine would quite due to my light Catto prop and extended idle power. I did not quit, but I did get a low oil pressure warning at 45 psi once during the spin entry from it getting close to around 400 RPM.
The only surprise I might note is that my Dynon Skyview ADAHRS took about 5-8 seconds to recover to a normal attitude once I had pulled out wings level. Not a knock on Dynon at all, they talk about this in their ops manual, but I had never seen it before.
I would encourage everyone who flies an RV to go out and get spin training and learn how your RV, as configured, behaves in a spin and how to recover from a spin to prolong the RV Grin.
In my first 135 hrs of flying my RV-8, I have come to appreciate just how efficient it is with an IO-320 and a Catto prop, excellent speed and maneuverability. Now that I am expanding the flight envelope beyond straight and level flight, I coming to appreciate just how great a design the RV aircraft are.
 
As an instructor, and against the better wishes of the flight school I was working for, I always gave my primary students spin training. It is a bit unnerving and maybe even scary the first time, but once you learn the recovery technique spins are just no big deal (when performed from a safe altitude). The last thing I wanted was my signature to be in someones logbook that had no exposure to the most frequently talked about danger in aviation.

Over the years I've flown with pilots of varying experience levels in aircraft with varying capabilities. I find it alarming when an experienced pilot is afraid of doing stalls in their own airplane. If you don't want to do them by yourself at a safe altitude, find an instructor with some knowledge/experience in your model of aircraft and go do it at least once a year.
 
I find it alarming when an experienced pilot is afraid of doing stalls in their own airplane.

I remember when I was instructing full time we had a renter at the FBO I worked for who was a good and careful pilot. He told me he wanted to get his CFI to have a retirement hobby in a couple years and so we began his training. On one of the very early lessons we discovered he had a strong aversion to stalls and spins because his initial instructor years ago was afraid of them. I bet we did 100 plus stalls and spins of all kinds over the next few lessons.

A few years later I bumped into him in an airline terminal and we got to talking. He had since retired and was doing a little teaching for fun and he thanked me for taking the time to make sure he was comfortable in the flight regime so he would not pass along a fear of stalls and spins to his students like his instructor had done to him.

Moral of the story, respect the stall spin environment but get good training so you are not afraid of it. Kudos to the OP for taking the time to work carefully down the path.
 
All to the left?

I'm a little curious why the OP did all the spins to the left? Engine gyroscopic effects and airframe asymmetries can yield somewhat different behavior left and right spin. Be good to do both I would think.

Also would be good to work the C.G. farther aft. I confess I have not done that either. Curious of the experience of someone who has.

I checked the spin after about a half turn, mission accomplished from the standpoint of reacting to an inadvertent spin, you are going to command recovery immediately. But I have not explored what happens if you really let it get going.
 
Left and Right Spins

I'm a little curious why the OP did all the spins to the left? Engine gyroscopic effects and airframe asymmetries can yield somewhat different behavior left and right spin. Be good to do both I would think.

Also would be good to work the C.G. farther aft. I confess I have not done that either. Curious of the experience of someone who has.

I checked the spin after about a half turn, mission accomplished from the standpoint of reacting to an inadvertent spin, you are going to command recovery immediately. But I have not explored what happens if you really let it get going.

My -8 seems a little odd. Up to 2 turns, spins to the right are slower than spins to the left, as would be expected (due to P-factor, even at idle). In this regime, spins to the right stop rotation almost immediately upon aplication of opposite rudder even before neutral elevator. Left spins require opposite rudder, then neutral elevator and the recovery occurs in about 1/4 turn after the neutral elevator.

The weirdness is the right hand spins that go beyond approximately 2 turns. At that point, there is a noticeable increase in rotation rate and recovery then requires significant forward stick (after opposite rudder) to break the stall, and recovery seems delayed (1/4 to 1/2 turn). Left spins remain consistent beyond 2 rotations. I've done up to 5 rotations in both directions.

This is solo in an -8 with an angle valve IO-360 and 74" Hartzell BA prop. i.e. CG towards the forward limit.

Skylor
 
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Spins

P factor has minimal effect at idle power. Aircraft with clockwise rotating props always seem to enter the spin more cleanly to the right. Remember the fin is offset to counter the p factor at cruise power, at idle power spin entry the fin offset is trying to yaw the airplane slightly to the right.
The difference in rotation rate is what I would expect.
At two turns you are barely past the incipient stage.
Forward stick should be whatever it takes to stop the spin. Always lead with the rudder. You may be at a point where you want to try some accelerated spins. Power off, after spin stabilizes move the stick to neutral elevator or slightly forward. The rate of rotation will increase dramatically. Rotation should stop more rapidly with application of opposite rudder. Many airplanes will recover with only neutral rudder.
Another method you could try is to center all controls, leading a bit with the rudder.
As you experiment with moving the cg aft elevator input becomes more critical.
 
Be careful as you move the CG aft

My 8 recovers in less than two turns at forward CG. But as the weight/CG gets to the maximum/aft of the aerobatic limit it tends to get progressively flatter and the recovery takes longer. In one case I had a 6 turn spin take an additional 5 1/2 turns to recover. This was unplesant. Don't think think that an RV spin is fully developed after two turns. In mine every turn is different up to number 6, which is as far as I have taken it.
Cheers
Nige
 
There is no offset in the fin of the RV-8.

P factor has minimal effect at idle power. Aircraft with clockwise rotating props always seem to enter the spin more cleanly to the right. Remember the fin is offset to counter the p factor at cruise power, at idle power spin entry the fin offset is trying to yaw the airplane slightly to the right.
The difference in rotation rate is what I would expect.
At two turns you are barely past the incipient stage.
Forward stick should be whatever it takes to stop the spin. Always lead with the rudder. You may be at a point where you want to try some accelerated spins. Power off, after spin stabilizes move the stick to neutral elevator or slightly forward. The rate of rotation will increase dramatically. Rotation should stop more rapidly with application of opposite rudder. Many airplanes will recover with only neutral rudder.
Another method you could try is to center all controls, leading a bit with the rudder.
As you experiment with moving the cg aft elevator input becomes more critical.
 
My 8 recovers in less than two turns at forward CG. But as the weight/CG gets to the maximum/aft of the aerobatic limit it tends to get progressively flatter and the recovery takes longer. In one case I had a 6 turn spin take an additional 5 1/2 turns to recover. This was unplesant. Don't think think that an RV spin is fully developed after two turns. In mine every turn is different up to number 6, which is as far as I have taken it.
Cheers
Nige

Thanks Nigel, very informative. Yikes, after a couple of turns beyond recovery inputs, I'd be ready to step smartly over the side. I don't think I have the patience/nerve to ride out 5 more turns!
 
Second on Nigel's remarks. The RV-8 is a little different. Personally, I never spin mine with someone in the back seat. Gets too deep with CG aft.

Also, the -8 will tighten up nicely in a spin with opposite aileron, applied once developed.
 
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