What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Impossible Turn (RV4)

PhatRV

Well Known Member
AOPA just released a new video showing a variety of real world testing using the SuperCub, C172, RV4, and the Bonanza, performing the "impossible turn" using a variety of altitudes when the engines failed.

What surprise me is the RV4 failed to make the turn-back 1 out of 3. I had assumed the RV4 excellent climb rate is advantageous for this kind of maneuver. The C172, despite its low climb rate, made it back from all altitudes, as low as 600 ft.

Link to the video:
https://www.youtube.com/watch?v=dFVFKq3QqXo

RV4 in the video:
https://youtu.be/dFVFKq3QqXo?t=290
 
Last edited:
As the narrator said, about the Bonanza (but also somewhat true for the RV), the issue is a relatively (compared to the cub and 172) higher best glide speed. The higher Vglide means a larger radius turn, so more distance to be covered to return. Note the test was done from various altitudes, not various times since lift off. If done, say, 30 seconds after lift off, the RV would have an advantage since it would be higher than the others.
As an aside, I think it would have done better if a steeper bank had been used. This needs to be done carefully, as you are pushing closer to an accelerated stall, but I think best results are obtained by banking the plane until the AOA starts beeping. I’m pretty sure that with the cub, I could hear the stall horn occasionally chirp in the turn.
 
Yep, a steeper bank angle! I practice the turnback about once a week from 600' AGL, wait five seconds, keep 90 mph and a 45 degree bank, prop to low rpm. I make it back easily in RV-4. 600' AGL usually catches me ready to turn crosswind at around 110 - 120 mph flaps up.
 
I think the test was preformed from the takeoff to the turn back altitude. With the anemic climb rate of 172, it would be located far away from the runway at a specific altitude where as the RV4 with a much higher climb rate, would be closer to the airport when compare to the 172. But the video also mentioned of the RV4 constant speed propeller slowing it down during the glide.
 
AoB

Nice posting!

It didn't look like a solid 45 degrees in the video.

I have procrastinated these tests in my RV-7 so I guess it's time to get them done.

Guidance I have heard from the chicken coop is 60 degrees for the AoB. I'll try that.
 
Last edited:
Really interesting. Here's my results---and I'm respectfully not pushing this on anybody, this is just me.
I regularly practice this about every 6 months. (Had originally done this at altitude of course, for obvious reasons) I have an 8. At my home airport, if one has an engine failure on T/O, there's absolutely no place to go, except into the side of buildings.:eek: Bummer. So I normally climb with my nose at about 18 to 20 degrees nose up. Then I pull the throttle, leave the nose there, count 1001, 1002, 1003, 1004 for the startle factor. Then of course, I push the nose down. I found that I can't go over 45* bank, or slower than 85 Kts indicated, or the plane starts rumbling meaning stall is right there. I'm also cranking out full flaps at the same time. Pulling my prop to full course pitch would help the glide ratio of course, but I'm afraid to try that so low, in case it doesn't come back. I found I can make it from 700' agl, but I've decided to not try it unless I have at least 1000'. (Fudge factor) Practice it both ways left and right. One other trick, at least at a non towered airport, is to take a 20 to 30 degree left or right cut right after takeoff for maybe 5 seconds, or whatever, the come back to runway heading. Then you're already sorta getting set up, so one doesn't necessarily have to make that full 270* turn to come back, if your engine does indeed fail.

If anyone has any better ideas, I'm all ears.:D
 
Last edited:
I was giving a BFR in an RV-8 the other day and we tried this up at 4000AGL.
Long story short, 1000' is what it took.
Granted, we were right up near gross weight and up in altitude a little but it was probably a fair representation of the average capabilities.

Could we have got that number down had we done it multiple times? Absolutely.
The problem I see with that is if you do it 6 times one day and get the number down to say 600' then set that as your personal base line, you need to continually practice it so you can maintain the proficiency in what frankly can be a very dangerous maneuver when you have the bad day.

Don't misinterpret my intent. If you have figured out what your number is and practice it regularly then I think keeping the impossible turn in your back pocket as a viable option is a fine thing. If you do it once or just take somebody else's number and never practice it, please just aim for something soft and cheap that was between the wingtips when the engine gave up.
 
It would be interesting to do a whole series of 360 degree turns at various bank angles and flap settings and speeds, to see what the lowest altitude loss is.

Dave
 
I'm surprised that they didn't mention

Know the layout of your airport.


Although not all airports have multiple runways, it may be easier to land on a parallel or crosswind runway (or even taxiway)..........
 
I'm surprised that they didn't mention

Know the layout of your airport.


Although not all airports have multiple runways, it may be easier to land on a parallel or crosswind runway (or even taxiway)..........

In that situation, the big win is making a survivable arrival - probably on something flat without big obstacles. There are lots of areas on most airports that qualify. Making it back to the actual runway is the cherry on top.

And if you're gonna practice this, get a feel for it at a safe altitude before you even consider doing it at low altitude.
 
Altitude loss is not the whole story. A tight turns gets you back to the runway with less distance traveled.
 
This is certainly not the best reporting of the turn back. But they were probably limited by print space or reading time. It is not just about altitude and skill.

EAA Webinar is the best analysis/presentation on this subject I have seen and it was based on fundamentals - the real variables. Highly recommended!!!

I was taught to unload the wing for allowing a 180 with less lateral distance/descent and avoidance of stall.

Pulling back my CS prop will greatly help. YMMV
 
Last edited:
I've done this quite bit in Cessna products on BFR's or whatever, Hopefully it goes without saying that for training I pick an entry altitude that allows for a stall recovery if it's botched.

On a 172, the least altitude loss is consistently achieved while holding best glide and a bank angle that has the stall horn going off, but yeah, It's possible to get one turned around with just a few hundred feet of altitude loss.

Probably not something I'm going to recommend somebody tries in a real engine out when they're close to the ground and freaked out anyway, unless they have absolutely no other options. A stall, or God forbid, an uncoordinated stall leading to a spin entry would almost surely be fatal.
 
The trouble with engine failures they always catch you by surprise and they very seldom happen at a convenient time or place. But training is best it shortens the time you say aw sh**t to the time you get things under control.
 
In that situation, the big win is making a survivable arrival - probably on something flat without big obstacles. There are lots of areas on most airports that qualify. Making it back to the actual runway is the cherry on top.

And if you're gonna practice this, get a feel for it at a safe altitude before you even consider doing it at low altitude.

There's also lots of talk about how great RVs are on short runways. Long runways provide more option to land straight ahead, or to make it back to some part of the airfield. The thing about long runways is they are usually at big airports. Big airports have better crash/fire/rescue. I'd rather crash on a "field" (soft mucky grass between taxiways) with a fire truck 90 seconds away than nose over in a corn field with the fire truck 15 minutes away. Then again, don't crash trying to make it back to the airfield and ignore a perfect empty parking lot. Awareness of surroundings is the important part.
 
Thinking out loud here, but wouldnt it be better to practice with prop lever full fwd (worst case scenario), since thats where it will go if engine loses oil pressure?
 
Maybe. If the engine fails it will likely be still producing oil pressure (turning). I going to try it high rpm and see how much difference it makes.
 
Maybe. If the engine fails it will likely be still producing oil pressure (turning). I going to try it high rpm and see how much difference it makes.

ABCs Wide World of Flying did a video on "extending the glide" several years ago.

Using a C-182 the difference in glide between course pitch and a stopped prop was a somewhat amazing 26%.

Of course the demonstration was at altitude where you would have time to evaluate circumstances. This might not necessarily apply on initial climb-out situation.
 
I think you can do better with flaps retracted.

You'd be best off where the flaps are providing more lift than drag... the 10 degree takeoff setting would apply. Don't go for more than that until you're sure you're too high or too fast on the final approach.
 
Using the prop control for simulated failures

Hello All,

I did some experimenting on how to simulate engine out in my airplane and found some useful information.

First off, each airplane engine/prop combo will be different. My MT three blade composite on a YIO 390 will yield prop control down to about 1100 RPM. I know people with two blade props that lose control below 1500 RPM. So it depends on your set up.

Next I did a LOT of engine out testing. That's no fuel-no power. Pulling the blue knob all the way out made a remarkable difference in glide. AND the sweet spot for the throttle was anywhere above 12" MAP. Yes, for my set up best glide involved letting the engine breath a little increasing RPM by about 150. Counterintuitive but if you are windmilling and stealing power then at a set pitch faster is better.

So once I found my true glide numbers I found the prop position to replicate the same drag with the engine at idle. For me 1350 RPM at idle is the same as best glide configuration.

For anyone who compares my airplane achieved max range glide very close to 120 MPH and 1100 fpm.

Obviously an engine seizure or prop failure will change everything, and I have no way to test that without doing something really scary.
 
Really interesting. Here's my results---and I'm respectfully not pushing this on anybody, this is just me.
I regularly practice this about every 6 months. (Had originally done this at altitude of course, for obvious reasons) I have an 8. At my home airport, if one has an engine failure on T/O, there's absolutely no place to go, except into the side of buildings.:eek: Bummer. So I normally climb with my nose at about 18 to 20 degrees nose up. Then I pull the throttle, leave the nose there, count 1001, 1002, 1003, 1004 for the startle factor. Then of course, I push the nose down. I found that I can't go over 45* bank, or slower than 85 Kts indicated, or the plane starts rumbling meaning stall is right there. I'm also cranking out full flaps at the same time. Pulling my prop to full course pitch would help the glide ratio of course, but I'm afraid to try that so low, in case it doesn't come back. I found I can make it from 700' agl, but I've decided to not try it unless I have at least 1000'. (Fudge factor) Practice it both ways left and right. One other trick, at least at a non towered airport, is to take a 20 to 30 degree left or right cut right after takeoff for maybe 5 seconds, or whatever, the come back to runway heading. Then you're already sorta getting set up, so one doesn't necessarily have to make that full 270* turn to come back, if your engine does indeed fail.

If anyone has any better ideas, I'm all ears.:D
I think the impossible turn is, well for lack of a better descriptor, foolish below 1000ft. Not impossible but foolish. RV’s have a slow stall. Really slow stall with full flaps and a good flare. So wings level and fly through crash below 1000ft is what I’ll do if doing a straight out departure.

Having said that, at a field without any traffic a 400ft crosswind and a short field takeoff will most likely facilitate an on-field landing. RV’s get off the ground so quickly that at 400 ft you’re still over the field and if turned 90 degrees at that point you have a lot of options. Also if turning at 400ft you can most likely land on field below around 300ft straightahead. So it only gets dicey at the 300 ft to 400 ft range (which is about 2 seconds). If the engine is still producing power at 400ft you will get through the 90 degrees. AT THAT POINT you can make it back.

Since you’re ok to turn Crosswind at 400ft at most fields that’s the safest thing to do. Yes it’s nice to depart at 110-120 for best performance, cooling, and fun I think if you’re looking at the “safest” takeoff with regards to an engine out the short field 400ft crosswind turnout to the side with the best outs is the safest technique.

To add another level of complexity although “no turns below 400ft is often taught” some say AND the end of the runway. There are also “Noise Abatement Procedures” and general courtesy so it may be good to ask for an early turn at a controlled field and to announce at an uncontrolled field. Lastly, of course, it depends on the terrain at your aerodrome of departure. If there are good outs that are facilitated by a different departure sequence of course that is probably safest. i.e. there’s an abandoned parking lot ahead 45 degrees a mile out from the departure end of the runway. Common sense always rules the day.

JMHO and WTHDIKA
 
Last edited:
Lots of good advice in this thread. I have experienced two engine out landings.
I certainly practiced slow flight with turns (at a safe altitude) and had quite a bit of confidence in that flight condition, with engine idling.
However, the reality is, that with our slick planes with the prop that is just turning at idle, is still generating a lot of thrust.
On my first engine out it was, fortunately, over the airport. I had time to set things up and used what I had practiced. I remember thinking I am too high and it is possible, based on prior experience, that I might just run off the other end of the runway. The reality was that without the prop turning I ended up on the the approach end of the runway. This was a real eye opener for me.
The bottom line is that you should plan to land shorter then your practicing would lead you to believe.

Having that experience allowed me to land safely in a soybean field with no damage to the aircraft in the second engine failure. Without the knowledge I gained from the first incident the result might not have been so positive.

From that time on with all subsequent airplanes I have accepted nothing less then getting engine work done at certified shops to certified standards. This has resulted in 25 years of safe engine operation.
 
Last edited:
Turn Back

Sunrise Aviation at John Wayne Airport (SNA) teaches turn backs to their student pilots. This is done because of the hostile environment around the airport. Some time ago (different flight school) a student with another student in the back and instructor in right seat landed a Cherokee on a busy city street near SNA after an engine failure. No damage to airplane.
Sunrise has some excellent videos available but I can't find the best one which is a simulated engine failure on takeoff at a dirt strip in that area.
The AOPA information appears to fall short of the information from Sunrise for the 172.
The RV4 with constant speed and the Bonanza with three blade constant speed produced very understandable results. In my experience from many years ago it took 1200 AGL abeam the numbers for a a successful power off landing in the A36 with bank limited to 30 degrees.
The bank angle is the key to this and anyone who is not completely comfortable and skilled with 45 degree bank turns near the ground should not attempt this.
Another issue that has not been discussed enough is a stopped prop. The Pitts airplanes are notorious for high sink rates power off. This is mostly because of the effect of the wind milling prop. This is MUCH worse with constant speed.
Many years ago I watched a VERY skilled Pitts S1 pilot dead stick successfully from a VERY low altitude two days in a row. In both cases the engine stopped during a tailslide. No starter. The keys to the success were two issues. The prop was stopped-even with fixed pitch the Pitts glides much better with prop stopped. #2 is that the pilot did not even consider the end of the runway. He immediately set up a modified base leg with the aiming point at least 1000' from approach end. These were very close calls, with the airplane rolling out of a 30 degree plus bank only about 20' off the ground.
One more comment on the AOPA videos- I think all the turns were well short of 45 degree bank. Very significant, 35 degree bank will probably cost 100' for the 172.
i have been working on this with my Wittman Tailwind. I am totally confident that I can do this from 400' AGL. I am somewhat confident that I can do it from 300'.
A few months ago there was an excellent video of RV4 turnback practice at a grass strip. I don't remember the exact numbers but the altitude was very low.
 
The conventional wisdom developed for 172s and Cherokees and their pilots doesn't necessarily apply to higher performance machines. For example, I've done a lot of testing of the turn back in my Giles (because there's nowhere safe to land straight ahead at my home airport), and I find I get the turn done the quickest, with the least altitude loss and wind up closest to the runway if I use a vertical bank.

My interpretation is that all of the lift goes to turning the plane and none is wasted holding it up. Of course the plane descends rapidly, but the turn is over so quickly it doesn't fall very far. A bonus is that with all of the lift doing only one thing I find it easier to fly the wing to just above the stall.
 
Turn Back

Not just wall to wall buildings to consider. In many agricultural areas fields are frequently flooded from irrigation. In some cases it is near impossible to determine the condition of a field from the air. My home base is surrounded with farm fields that are frequently irrigated. So the nightmare scenario is an attempted engine failure landing in one of these wet fields that results in the airplane upside down(a given) and perhaps I am disabled. So I'll take the turn back every time above 300' agl.
Two other issues for non tower fields that are not often discussed: No significant crosswind, no terrain considerations, turn slightly to the right, especially with side by side airplane. This will give you a good look at the runway and will slightly lessen the minimum altitude required for turn back.
If there is significant crosswind let the airplane drift away from the runway centerline. With a lot of crosswind the turnback becomes much closer to a pure 180 with no extra maneuvering.
In the Wittman Tailwind at any altitude above 400' a downwind landing becomes the most critical part of the turn back. My plan is to sidestep to the right and fly a downwind leg if I am above 400' when the engine quits.
 
Lots of good advice in this thread. I have experienced two engine out landings.
I certainly practiced slow flight with turns (at a safe altitude) and had quite a bit of confidence in that flight condition, with engine idling.
However, the reality is, that with our slick planes with the prop that is just turning at idle, is still generating a lot of thrust.
On my first engine out it was, fortunately, over the airport. I had time to set things up and used what I had practiced. I remember thinking I am too high and it is possible, based on prior experience, that I might just run off the other end of the runway. The reality was that without the prop turning I ended up on the the approach end of the runway. This was a real eye opener for me.
The bottom line is that you should plan to land shorter then your practicing would lead you to believe.

Having that experience allowed me to land safely in a soybean field with no damage to the aircraft in the second engine failure. Without the knowledge I gained from the first incident the result might not have been so positive.

From that time on with all subsequent airplanes I have accepted nothing less then getting engine work done at certified shops to certified standards. This has resulted in 25 years of safe engine operation.

Shoot---I don't think I want to fly with you:D:D:D
Seriously, what kinds of airplanes were your 2 engine failures in? RV's?
 
Turn Back

That is the one. Some incredible flying. Does show how much easier it is with fixed pitch. Makes the AOPA people look like amateur hour.
 
Vac's Turnback

Seems like energy is coming from somewhere or an RV-4 is a very different animal than the -7

My true best glide wings level is 1100 fpm. Vac's got to give energy in the turns but is still still managing some very low rate of descent. Avg less than 500 fpm?

AoA is the way to go of course, but I gotta think with personal a wings level VSI of 1100 fpm best glide I am going to see much higher rates of descent in my turns.

Gotta get out there and do it I guess.
 
Last edited:
Great Discussion

I love VAF...this is the kind of discussion that makes this site (thanks Doug) an absolute gem in the EAB world. It's not my intention to turn this into an AOA discussion (or bar fight of AOA vs airspeed), just offering some observations based on experience and lots of instrumented testing of the RV-4...

Some points to ponder in no particular order:

1. The "impossible turn" is actually a low-altitude target re-attack. This is something that air to ground guys are generally reasonably good at. Turn rate/radius and energy management is the key. In this case, you have come off target at a relatively low energy state, but the FAC (forward air controller) wants you back in ASAP on a reciprocal axis. The "target" is the TDZ, and the attack parameters are to be in a three point attitude at an energy state commensurate with touch down over the TDZ.

2. Only two factors affect turn performance: radial G and TAS. A steep, high-rate turn is more productive when overall energy is low (i.e., not very high or fast); but it can be eye watering if you are not used to maneuvering relative to the ground (think crop duster or A-10). Absolutely possible to manage turn performance using airspeed and G, but both will vary considerably depending on conditions.

3. Using AOA as primary reference greatly simplifies ANY maximum performance maneuvering in any airplane (think 1 v 1 combat or coming in to land). There is one sweet spot AOA that results in maximum sustained turn performance under any conditions: ONSPEED.

4. An airplane cannot stall ONSPEED. An airplane lands ONSPEED.

5. AOA is not effected by aircraft gross weight, G load or density altitude. It doesn't care about bank angle. If I can hear the AOA, I don't have to look inside the airplane when I'm maneuvering.

6. When maneuvering close to the ground, some use of flaps may be beneficial, depending on the airframe and pilot skill level. It's already been mentioned in this thread, but a flap setting that produces more lift than drag can be useful. L/Dmax decreases with flaps deployed and marries up nicely with ONSPEED. This isn't optimum glide performance (that happens at L/Dmax and flaps up), this is an optimum COMPROMISE of energy bleed and turn performance. If range is the ONLY consideration, maneuver in reference to L/Dmax AOA. In the video, I'm using half flaps (20 deg) in the RV-4. I'd prefer 10 degrees, but my manual flaps have only two settings.

6. Keep ground track in the cross-check (axis of attack, i.e., if landing on runway 27, heading of 270 degrees). You have to offset the turn circle from the desired ground track, and an easy way to do that is to remember to "lean into the wind." This will compress the size of the turn circle relative to the ground. You should have a pretty good idea of wind direction if you don't have a cockpit read-out since you just took off.

7. A turn-back isn't a 180 degree turn. It's at least 270. If you know how much altitude you lose in an optimum power-off 360, that will put a little extra in the bank. If you don't have a properly calibrated AOA, it's gonna' be a lot harder; but you can develop some good rules of thumb regarding Vref and bank angle.

8. Keep any altitude while you establish an optimum glide condition. It goes without saying that you don't want to stall; but if you're listening to your AOA on takeoff, it's pretty straight forward to hear the airplane decelerate to an ONSPEED condition when you begin to maneuver.

9. No slower than ONSPEED to the crash, wherever that may be.

10. There is no one size fits all answer, other than managing turn rate, radius and energy. Easier to do that when you've got some sort of energy cuing. That can be aural AOA (obviously I'm biased), but there are some good energy displays being developed by universities and NASA that will likely find their way to EAB first. The EAA "crowd sourcing" experiment for data is an awesome idea.

11. Experiment. Doesn't matter what kind of airplane. Participate in the EAA program if you are so inclined. Also mentioned above: use a three-count or something similar at the start of the drill, since there will be a MUCH larger pucker factor real-life. Work from high to low, i.e., experiment at altitude. Don't exceed your comfort level. If you aren't trained and plan to crash straight ahead or within thirty degrees of the runway centerline, amen. Be respectful in the bar fight and remember there isn't one right answer ;)

12. The flying in the demonstration video isn't hard to do--I'm not that good. All I'm doing is deploying lift flaps, maintaining ONSPEED and doing whatever it takes to get to the TDZ. The airport in the video is surrounded by farm fields on the east end, so that is a tactical advantage for maneuvering.

13. Prop drag is a huge factor in glide performance. Not much use trying to stop the prop below 3K' AGL unless you are very familiar with the technique in your airplane. Harder to do with a controllable prop.

14. Fixed-pitch props produce residual thrust in IDLE. Therefore, if you do your practice in IDLE, remember actual engine-out performance will differ. Add wind to that equation and you can see that each occurrence has the potential to be unique; but that doesn't mean that you can't practice and "what if" it to develop a gameplan for your airplane.

15. If you are going to maneuver, do it NOW. Energy will NOT improve with time if the engine isn't working.

And here is the mighty RV-4 sitting mid-field after the carburetor decided to stop participating in the combustion process recently:

3c039a_0b7c8d48df55441a867d42be28f77c13~mv2.jpg


An engine failure is never a non-event, and this one occurred during return for landing, not immediately after takeoff; but the point is that it's nice to have a good energy reference to fly when you want to max perform the airplane. Since 1979, this engine non-cooperation event number five, so my list of willing passengers is getting smaller (two, however, where in twin engined fighters--lower pucker factor when you've got a spare with lots of thrust).

Fly safe,

Vac

Here are a list of some technical resources discussing the topic:

Should You Turn Back? https://www.nar-associates.com/technical-flying/impossible/possible.html

The Feasibility of Turn Back From a Low Altitude Engine Failure During the Takeoff Climb Out Phase. https://www.nar-associates.com/technical-flying/jett/jett_wide_screen.pdf

The Possible "Impossible" Turn. https://www.nar-associates.com/technical-flying/impossible/impossible_wide_screen.pdf

Estimating the Turn Back Altitude. https://www.nar-associates.com/technical-flying/impossible/EstimatingTurnbackAltitude.pdf

The Penalties of Non-optimal Turn Back Maneuvers. https://www.nar-associates.com/technical-flying/impossible/nonoptimalcost_screen.pdf
 
Last edited:
Hey Vac

Thanks for getting in this.

And thanks again for posting that training syllabus! Anyone who hasn't seen it should take a look.

Your video was introduced on this thread as a 250' AGL turn back. Can you confirm or deny you can make that happen at that height?

-Duck
 
Affirm. 250’ AGL at L/Dmax AOA. Field elevation in the video is 250’ MSL.

V/r,

Vac
 
Last edited:
ABCs Wide World of Flying did a video on "extending the glide" several years ago.

Using a C-182 the difference in glide between course pitch and a stopped prop was a somewhat amazing 26%.

Of course the demonstration was at altitude where you would have time to evaluate circumstances. This might not necessarily apply on initial climb-out situation.

Thanks for being the voice of reason, logic and aerodynamics.
 
I doubt very much that if you had an engine failure at 250ft that you would make it back to the runway. There is the reaction and realization time that takes up precious time to make the decision to turn back. Go up to altitude and practice doing it with someone with you. Their job is to turn the ignition off with out any warning to you and then you will have a better idea of the lost time and with no thrust, the type of actual height lost. You will discover that you have very few seconds.
 
Engine shutdown

Turning the ignition off is ok and the only option available with a 65 Continental. NOT a good idea with larger engines. Pull the mixture to cutoff With wind milling prop push the mixture back in and you will get a smooth and dependable restart.
Simulated engine failure in piston twins done properly is mixture to cutoff, throttle and prop to estimated position for zero thrust, then mixture rich. This is the procedure that is "kindest" to the engine.
 
Sunrise Aviation at John Wayne Airport (SNA) teaches turn backs to their student pilots. This is done because of the hostile environment around the airport. Some time ago (different flight school) a student with another student in the back and instructor in right seat landed a Cherokee on a busy city street near SNA after an engine failure. No damage to airplane.
Sunrise has some excellent videos available but I can't find the best one which is a simulated engine failure on takeoff at a dirt strip in that area.
The AOPA information appears to fall short of the information from Sunrise for the 172.

I believe the Sunrise video you're referring to is here:

http://www.aerobats.com/seminar_02-07.html

I learned to fly at Sunrise. It was a good place to learn because students experience aerobatics from the start. They don't allow any student solos until they've done spins. As I recall, I did 1, 2, and 3 turn spins in both directions in a Decathlon prior to soloing. I might have had 15 hours total time at that point.

I also worked as an instructor there for many years, as well as teaching primary and advanced aerobatics in the Citabra, Decathlon, Pitts, and Extra 300.

I've made multiple returns from 500' AGL in a fixed (cruise) pitch RV-6 without a problem. I used 60 degrees of bank. The rate of descent is high in the turn, but the turn doesn't last very long at that angle of bank either. I found that my problem wasn't making the runway, it was overshooting after the landing. I only did this when the winds were relatively calm because I am not a fan of landing tailwheel airplanes with a tailwind.

Pilots tend to get focused on making it back to the runway. While this is optimal, it's unnecessary. All I want is to get back on the airport property, where the land is flat, there are no obstructions, and so on. I can land on grass, a ramp, a taxiway, anywhere. If the plane gets damaged, that's fine. A low altitude engine failure is a pretty serious emergency, and all I'm looking to do is survive.

It has been noted that the RV has a low stall speed. While this is true, it does develop a high sink rate if you let the speed get too slow. Just something to keep in mind.

I owned a Pitts S-2B as well. One of my favorite things to do on a flight review with experienced Pitts pilots is to give them a simulated engine failure on downwind. Because aerobatic airplanes sometimes suffer momentary drops in oil pressure during acro, the props are built in such a way that a loss of oil pressure drives the prop to high pitch (low RPM) rather than the typical low pitch (high RPM). So I give them the engine failure with the prop at low RPM, and almost without fail they badly overshoot even a relatively long runway, even with an extreme slip. It's a great lesson, and a reminder that a significant percentage of the drag comes from the prop.

--Ron
 
Turn Back

Ron-
Great post. I can't believe how many people refuse to believe the drag scenario of a windmilling constant speed prop. An excellent way to explain this is to use any light twin for example. Windmiling prop-airplane descends with full power on operating engine. Feathered prop airplane will at least maintain level flight at low altitude and may even climb a little.
My experience is that almost all the short wing homebuilts have similar issues with high sink rates at low speed. Pilots who routinely use a significant amount of power on a normal approach will have a tough time dealing with a turn back.
 
Thinking about a Windmilling Prop when building

It just occurs to me that there is anecdotal evidence about which props allow for control in windmilling situations and which revert to fine pitch because of lack of RPM, but I never saw that aspect as a buyers point to consider.

This should be available as a builders purchase consideration. Perhaps not first or second tier priorities but if one is torn between two choices, the knowledge of which one is still responding during windmilling might be meaningful.

Anyone ever seen a list of which ones retain control and which do not? Should just be a function of RPM, prop and prop governor yes? Or are some engines providing reduced gearing at the governor pad?
 
Last edited:
I owned a Pitts S-2B as well. One of my favorite things to do on a flight review with experienced Pitts pilots is to give them a simulated engine failure on downwind. Because aerobatic airplanes sometimes suffer momentary drops in oil pressure during acro, the props are built in such a way that a loss of oil pressure drives the prop to high pitch (low RPM) rather than the typical low pitch (high RPM). So I give them the engine failure with the prop at low RPM, and almost without fail they badly overshoot even a relatively long runway, even with an extreme slip. It's a great lesson, and a reminder that a significant percentage of the drag comes from the prop.

--Ron

Interesting. I commonly observe the opposite problem. Put a PP in a 172, doing a Flight Review. Pull power to idle, announce, ‘engine failure, what are you going to do?’. We’re within easy gliding range of an uncontrolled airport. Invariably, they set up an approach to try to touch down on the numbers; some come in short. When asked why instead they didn’t aim a third or more of the way down the runway, they say, ‘I never practice that.’ You do what you practice.
 
When asked why instead they didn’t aim a third or more of the way down the runway, they say, ‘I never practice that.’ You do what you practice.

That is true. Ironically, even if they DID practice it, the vast majority of their landings would still be using an aim point near the runway threshold since that's how normal landings are performed.

My flight review observation had more to do with the dramatic difference in glide ratio of a Pitts (or other aircraft with a large wide chord aerobatic prop like the Hartzell Claw) at high vs low pitch. Obviously that's not a consideration in a Skyhawk... unless it happens to be an XP or other rare example with a constant speed propeller.

--Ron
 
Wingover ?

Just wondering if there is any scope for a wingover in a turn back.
I had some lessons in a C172 a long time ago which included wingovers to chase stock from the landing area.
As I recall the a/c was allowed to slow to something below 70 knots in the climb, power off, before lowering the nose and and applying full aileron and rudder.
It seemed like a simple and quick way to achieve a reciprocal heading without the risk of a stall from trying to hold altitude in a turn.
A more normal moving stock off the runway (always work on the side of the flock or herd) is this:
https://youtu.be/Wsc4p9HJDsE
 
The thread immediately below this thread in “Safety” was an attempted turn back after engine failure on takeoff according to initial reports. Pilot VERY EXPERIENCED. RIP
 
Just wondering if there is any scope for a wingover in a turn back.
I had some lessons in a C172 a long time ago which included wingovers to chase stock from the landing area.
As I recall the a/c was allowed to slow to something below 70 knots in the climb, power off, before lowering the nose and and applying full aileron and rudder.
It seemed like a simple and quick way to achieve a reciprocal heading without the risk of a stall from trying to hold altitude in a turn.
A more normal moving stock off the runway (always work on the side of the flock or herd) is this:
https://youtu.be/Wsc4p9HJDsE

A wing over requires you have significant energy prior to starting the maneuver which is normally a 1.5 to 2 G pull-up. If you lose an engine on initial climb the nose of the aircraft needs to go down rapidly or you will stall within seconds.
 
The thread immediately below this thread in “Safety” was an attempted turn back after engine failure on takeoff according to initial reports. Pilot VERY EXPERIENCED. RIP

This military pilot with that much experience failed to make it back, what chance for the rest of us civilian, and low time pilots will succeed at this maneuver without a lot of practice at altitude
 
This military pilot with that much experience failed to make it back, what chance for the rest of us civilian, and low time pilots will succeed at this maneuver without a lot of practice at altitude

From eye witness reports he was no where near 500' AGL. I try it around once a week in the RV-4, sometime to full stop but often to the point I can see I can clearly make it.
 
From eye witness reports he was no where near 500' AGL. I try it around once a week in the RV-4, sometime to full stop but often to the point I can see I can clearly make it.

There is one HUGE difference doing what you are doing and having the engine quit on you! The engine never quits at a convenient time and you are never 100% prepared for it, it all takes time from the moment the engine quits producing thrust to you realize that fact and then figuring out what you are going to do, mean while you are going down.
 
I think there’s one question that needs to be asked and that is “Would the pilot have survived had he landed straight ahead.”
 
Last edited:
There is one HUGE difference doing what you are doing and having the engine quit on you! The engine never quits at a convenient time and you are never 100% prepared for it, it all takes time from the moment the engine quits producing thrust to you realize that fact and then figuring out what you are going to do, mean while you are going down.

True. That is why I do a five count before taking any action. I also practice engine out at 100 and 200 feet getting it down on the runway straight ahead. I am not married to turn back. I'm not married to getting back to the runway. I would prefer to crash inside the airport perimeter so that someone might find me. I live out in the stix where someone might not come looking until I didn't show up for dinner.
 
Turn Back

One thing that will never be know is how many successful turn backs there have been.
I only know of one in what I consider a high performance homebuilt. It was very close because of lack of altitude but there were no other options. Trees, buildings and rough terrain.
Rereading the first attached message in post #31, the thing that surprised me is that most of the loss of control(simulated) came from overbanking. The poor performance in AOPA experiment appears to come from under banking.
Sunrise teaches 60 degree bank turnbacks to students, why is this such a big deal. The most significant answer appears to be poor quality or inadequate initial training.
The first attachment on message #31 is outstanding. The first time I have ever seen an in depth look at how to use crosswind to enhance the turn back. The only thing that was not mentioned is the option of letting the airplane drift off centerline on takeoff if the situation calls for it.
At some point, even on a relatively short runway, letting the airplane drift off centerline in an almost direct crosswind, results in the turnback being very close to a 180 turn instead of the near 270 turn required in no wind.
The other option I use, especially in initial testing, is to offset at least slightly to the side of the runway which once again results in a turn nearer 180 than 270.
I am not an RV pilot, but have flown a number of low wing and mid wing homebuilt airplanes as well as several Pitts models and many different biplanes. There is no doubt in my mind that the low wing airplanes, and to some degree mid wing airplanes are less tolerant of misuse of rudder in low altitude turns.
The extreme examples are the Lancairs, Midget Mustang I and II, to some degree the Glasairs. Judging only by statistics the RV's are probably better than most but still very unforgiving of misuse of rudder near the critical angle of attack.
I am based on an AG strip. The other day I stopped near the airstrip and watched the AG pilot work a field. Turbo powered Air Tractor, a big heavy airplane. 60 degree plus bank on the turnarounds. A vivid reminder that training, proficiency and CURRENCY make radical maneuvering close to the ground relatively safe.
 
Back
Top