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The impossible turn.

OK, first off, I do not fly aerobatics other than with my R/C models.

But, I wonder if anyone out there has any input about how an RV will act in a hammerhead turn???

When flying R/C stuff, I will either split S or pull up into a hammerhead if the engine fails on takeoff. Both maneuvers work better than a 180 turn to get back to the runway in my experience.

Obviously the RV will not perform exactly like the R/C---------but ?????????

This adds another factor to the mix------low level acro, but anyone out there ever played around-----at SAFE altitude----- with this to see what the plane will do???

rc-stall-turn.gif

Mike- deadstick hammerheads don't go so well...no propwach to pivot the airplane. And from a Vx or Vy climb, you will stall the airplane before you get vertical enough to even practice your glider hammerhead idea. As F1R says - Darwin award. In my Pitts, I can do a half turn spin in the same amount of altitude loss as the turnback, but this again would be pretty stupid, since during the turn if you can't quite make it around, you can always roll wings level before hitting the ground, which is a whole lot more survivable than not quite pulling out from a 1/2 turn spin.
 
OK, first off, I do not fly aerobatics other than with my R/C models.

But, I wonder if anyone out there has any input about how an RV will act in a hammerhead turn???

When flying R/C stuff, I will either split S or pull up into a hammerhead if the engine fails on takeoff. Both maneuvers work better than a 180 turn to get back to the runway in my experience.

Obviously the RV will not perform exactly like the R/C---------but ?????????

This adds another factor to the mix------low level acro, but anyone out there ever played around-----at SAFE altitude----- with this to see what the plane will do???

rc-stall-turn.gif
Might be helpful for a box canyon 180. But you can't wait until you're near stall speed, approaching rising terrain, and out of options.
 
VY or VX

Post above was.... Try to always climb at best rate until your at least at pattern altitude.

I was taught to climb out at best angle (VX) until you reach your turn back altitude. Get as much altitude as possible in the shortest distance.
Is there is reason to use VY instead? Is there is diference in approach to this with an RV as a training plane?
Always looking to learn...
 
Vx

Regarding Vx climb. I asked the same question to my
transition trainer. His response:
" If the objective is to get to altitude before you get too far from the airport Vx would be a better choice, the draw back being less reaction time and a greater loss of altitude to get to the 100 mph mark."

100 mph being the safe target speed to making
Steep bank descending turns returning to the airport.
 
Airspeeds

Google "Climb faster John Deakin" for an educational article about climb speeds.
I think of Vx as a speed to use for clearing a close in obstacle. The problem with using Vx to pattern altitude is that far too large a percentage of pilots will stall/spin before getting the nose down if using Vx. The greater the climb performance the greater the potential for disaster when using Vx when not appropriate.
 
Generally speaking, for light planes like RVs, Vx is almost only good for very tight obstacle clearance. The object 99% of the time is to get feet below the plane as quickly as possible.
 
Impossible Turn Test

After reading all of the posts here on VAF, and other sources of information on the ?Impossible Turn? it was time to go out and see what my RV8 minimum turn back altitude would be. Practicing at altitude did not yield much information, as it is hard to visualize what is happening without good ground reference. Even using the GPS did not add much value. So back to the airport I went. For each test, I climbed to the specified altitude at 90 Knots IAS, and pulled the power to idle while still in the climb attitude.
Test 1, 500? AGL: On Centerline of runway, Power to idle, rolled 45 degrees bank and lowered the nose to maintain 90 KIAS. First impression: The nose has to be lowered dramatically to maintain 90 KIAS! Second observation: The turn radius is larger than expected. In order to make it back to the field boundary, a turn of about 250 degrees was necessary. There was no altitude left to make the turn back to the runway; the best that could be hoped for was an on-airport crash. Starting the turn back toward the runway heading, light buffet was experienced (Thanks, Richard VanGrunsven, for making an aircraft that really talks to the pilot). Added power and went around to land and make another attempt. This test was obviously a failure. 500? is too low.
Test 2, 600? AGL: Same entry procedure as test #1. Again about 250 degrees of turn was necessary to get back to the airport boundary. The turn back to runway heading was much more difficult than I would have expected. I Lowered flaps during the turn back and was able to touch down on centerline, but had there been any obstacle, such as a row of trees, or any delay in initial response, it would have indeed been impossible.
Test 3, 700? AGL: Again, same entry procedure as test #1. It was possible to reduce the turn to less than 250 degrees and still make the runway. (I still used about 250 degrees of turn to keep it standard.) The turn back to runway heading was still uncomfortable, but I was able to lower flaps after the aircraft was established on the centerline of the runway. This test was repeated with the same result ? it can be done, but the pilot really has to be prepared for and have exactly in mind what to do.
Test 4, 800? AGL: Using the same procedures, the return to the airport was almost uneventful with the exception that the turn back to the runway centerline is still surprising. I was able to repeat this test uneventfully.
Test 5, 800? AGL, offset away from turn back direction by about 100 yards (moved to left of centerline, turn back to the right: Same procedures as Test 4, but the return to the airport was much easier.
Things learned:
*The nose must be immediately lowered to almost a dive to maintain 90 KIAS in the 45 degree bank turn.
*The turn radius will be greater than expected.
*The turn back to runway heading comes up faster than expected.
*The turn back to runway heading must be planned for, and dealt with aggressively.
*The angle of attack or airspeed and ball must be monitored obsessively to avoid getting slow or skidding.
*Do not try the ?Impossible Turn? unless you have practiced it on an actual runway to touchdown.
*Practice at altitude only helps to get the initial response (dive and 45 degree bank) learned.
*If there is no wind, turn to offset the line of flight away from the direction of the planned turn back to the runway. The return turn must be into the wind.
*Testing must be done in the aircraft that you fly
Caveats:
Testing was done solo, with half fuel (about 1450#)
The field elevation was 7600? (Pagosa Springs, CO) yielding a higher TAS than at lower elevations.
Wind was calm.
There were no obstacles in the area of the turn back circle.
 
Interesting exercise, Craig.

Which way would you offset with a strong crosswind? Why?

Thanks.
 
Interesting exercise, Craig.

Which way would you offset with a strong crosswind? Why?

Thanks.

Arlen, I think I would let the airplane offset with the crosswind. Then your turn will be into the wind and will be closer to having you lined up with the runway with a 180 degree turn. Offset is something I always try to think about before pushing the throttle forward, along with all of the other airport/runway/taxiway specifics that should be considered for each takeoff.
 
Caveats:
Testing was done solo, with half fuel (about 1450#)
The field elevation was 7600? (Pagosa Springs, CO) yielding a higher TAS than at lower elevations.
Wind was calm.
There were no obstacles in the area of the turn back circle.

You didn't mention adding any compensation for the couple seconds it will likely take to recognize (and believe) that the engine power has failed, and for the residual thrust you had since the engine was still running while doing your tests?
 
Practice

Craig. Great post. To reflect what I did differently
with the maneuver with an instructor in an RV-6.
My glide speed target was 100mph, 90knts is just a bit faster
At 103 mph. I was taught to make steeper turns 50-60 deg to get
Turning back faster. This 6 stalled in an accelerated level 60 deg bank
At 83 mph pulling 2g's in this case. So the descending 50-60 bank at 100mph was a good safety Speed for not stalling in the turn with less g's.
This was accomplished in a planned maneuver at 500 agl (at sea level) and there was no mind lag factor. I don't think it would have worked with a 5 sec delay that is advised.
Your very correct that you have to push the nose down aggressively to maintain
The airspeed. With the prop windmilling and not at idle this would require more force with immediate nose down trim and 100% commitment and focus on air speed.

I plan to practice this in an RV-3. Starting at 900 agl and counting 5 sec before steep banking the turn. My plan is to work down from 900 until I establish my min turn back Agl. The most important thing here is establishing the safe glide speed immediately before steeply banking the plane. I climb out at 100-110 mph for this reason. No where near Vx.
 
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The field elevation was 7600? (Pagosa Springs, CO) yielding a higher TAS than at lower elevations.

That is a HUGE caveat. At sea level, you'd probably have better success even at 500' AGL.

Speaking of which, you mentioned that starting from 500' the best you could expect was an "on-airport crash". If you meant stall/spin, that's bad. If you meant crunching the airplane, that's no big deal. The goal isn't to save the airplane, it's to walk away, and if you ever experience a total engine failure at 500' and walk away, the condition of the airplane will be inconsequential.

I once saw a Cessna 172 lose power at that altitude, make the turn back, and land on the airport property. The nose gear folded up and the prop was damaged, but nobody cared because the occupants were unhurt.

It's also worth noting that not all circumstances are created equal. I am based out of the highly congested L.A. basin. Turning around might be a better option for me than someone in, say, Nebraska who has other open flat-land possibilities nearby.

Every airport, every airplane, every runway, every wind/weight/CG/traffic combination is different. Aircraft configuration alone involves a large number of variables. Are you flying with a small engine and fixed pitch cruise prop out of a high density altitude location and no wind? Then your performance will have no bearing on someone with a big engine and CS prop flying out of a sea-level field with a headwind on departure.

One size does not fit all.
 
KLZU and buildings

I was always taught to land straight ahead. BUT the airport I'm based at, KLZU, with 99% of its takeoffs on runway 25, just leaves you no place to go except into the side of a building. Because of "that" and this thread, I went out and practiced these impossible turns, first at altitude, then on takeoffs. I'm not going to push here what I could or could not do, but rather the decision that I will only attempt this maneuver at my home airport of KLZU because of the buildings. Anywhere else, I will land straight ahead.

Just my 2 cents worth
 
Thoughts and clarifications

Van's Air Force is a great resource! Just reading all of the posts on this thread is a huge learning experience. Just to clarify a few points:
Al: I will try 60 degrees of bank on my next test; the reason I chose 45 degrees bank was that seemed to be the general consensus of this thread.
Ron: I'm certainly not trying to impose my ideas and experience on anyone; the purpose of the post was simply to share the experience that I had. The "on airport crash" was really meant to be an on-airport, off runway controlled landing that would probably result in damage to the aircraft, but allow the occupants to walk away.
An old, old Air Force adage stated that "any landing that you can walk away from is a good landing. Any landing after which the aircraft can be reused is an excellent landing."
Don: Again, no intent to force my ideas on anyone. Just sharing experience.
Thanks for the great comments, y'all!
 
60 deg

Craig. Putting the nose down to gain airspeed
To 100 mph and banking the plane 50-60 deg while looking
At the ground approaching quickly is not for the faint of heart
And requires 100% commitment to air speed and turning the plane around
As quickly as possible. When I first
Did this it scared the **** out of me. My instructor insisted I focus
on air speed, and we would be safe. Before I knew it we where heading back to the runway and leveling off the wings with a ton of energy and speed with no concern of having to stretch it out to make it.

I have not done this alone in the plane and plan to work my
Way into it. I am very grateful I was taught how it's done should I ever be in the situation with no other choice. Even if I was doing this at pattern, I would not do it in a shallow bank and slow airspeed.
If your going to do it you need to commit and get it done quickly with lots of
airspeed. "Air speed is life" a career pilot/ instructor drilled into me.
 
so,... let's beat this horse,.. so we're not dead

Seems to me, we are not fully framing the problem,.... if you get to the point of deciding to try and make the turn,.. (ability, training, tailwind input to touchdown speed and survivability, and surrounding conditions) ...the question is framed as how high do I need to be.

I think the question should be, between what altitudes should I even consider trying this turn. Seems most folks attempting are ending up high and fast,...when starting at "min decision altitude", so how much are you willing to add on until you are too high? Unless the other end of the runway is a lot friendlier, you've just bought a bad deal. What would be recommended for loss of altitude and airspeed at that point?
 
Turnback

The current issue of Air Classics Magazine is devoted mostly to Reno coverage. There is a short sidebar article by Hoot Gibson on dead sticking the Sea Fury after a total engine failure at race altitude.
In the history of Reno only a few Unlimited pilots have missed the runway. At least one ground loop to avoid going off the end. One of the most interesting was when Strega and Rare Bear both dead sticked to the now closed runway at the same time.
 
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