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  #21  
Old 06-05-2021, 08:42 AM
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Snowflake Snowflake is offline
 
Join Date: Oct 2009
Location: Sidney, BC, Canada
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Quote:
Originally Posted by BobTurner View Post
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.
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1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
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  #22  
Old 06-05-2021, 09:13 AM
wawrzynskivp wawrzynskivp is offline
 
Join Date: Feb 2018
Location: Incline Village Nv
Posts: 71
Default 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.
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  #23  
Old 06-05-2021, 09:24 AM
NewbRVator NewbRVator is offline
 
Join Date: Jul 2018
Location: CA
Posts: 279
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Quote:
Originally Posted by donaziza View Post
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. 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.
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
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Last edited by NewbRVator : 06-05-2021 at 09:48 AM.
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  #24  
Old 06-05-2021, 09:58 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
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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.
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Last edited by Tom Martin : 06-05-2021 at 12:06 PM.
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  #25  
Old 06-05-2021, 11:05 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,518
Default 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.
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  #26  
Old 06-05-2021, 11:37 AM
wil780 wil780 is offline
 
Join Date: Nov 2020
Location: Canada
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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.
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  #27  
Old 06-05-2021, 11:54 AM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,518
Default 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.
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  #28  
Old 06-05-2021, 12:26 PM
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donaziza donaziza is offline
 
Join Date: Jun 2007
Location: Atlanta
Posts: 807
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Quote:
Originally Posted by Tom Martin View Post
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
Seriously, what kinds of airplanes were your 2 engine failures in? RV's?
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  #29  
Old 06-05-2021, 05:35 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,518
Default 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.
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  #30  
Old 06-05-2021, 07:10 PM
wawrzynskivp wawrzynskivp is offline
 
Join Date: Feb 2018
Location: Incline Village Nv
Posts: 71
Default 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 by wawrzynskivp : 06-05-2021 at 07:47 PM.
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