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  #11  
Old 09-07-2015, 05:19 PM
agirard7a's Avatar
agirard7a agirard7a is offline
 
Join Date: Aug 2009
Location: Newport, RI
Posts: 705
Default Safe altitude

Rock, would you risk a straight in off field landing
If you lost your engine at 1k agl? My point is turning back
May be a safer alternative if A, you practiced this manuaver and
B, you where at a min safe turn back AGL.

A nose down high airspeed (100mph min and maintained)descending steep bank turn 45-60 deg will not stall the plane. The hard part is managing all that energy after you level off the wings and having brass ones with commitment putting the nose to the ground. The key to this manuaver is to not pussy foot with airspeed
or a non aggressive bank and knowing your own personal safe AGL. I have practiced this manuaver and personally have an altitude bug set at 600' above field elev. If I don't make it
Back to the runway, at least I'll be heading back toward it with a lot of energy.
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Al Girard, Newport, RI
N339AG
RV-9

Last edited by agirard7a : 09-07-2015 at 06:27 PM.
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  #12  
Old 09-07-2015, 05:24 PM
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Kevin Horton Kevin Horton is offline
 
Join Date: Jan 2005
Location: Ottawa, Canada
Posts: 2,357
Default

Quote:
Originally Posted by BobTurner View Post
Kevin, did you have the throttle full forward during the engine off test? That will help.
Keep in mind you will want an airspeed slightly slower than no-wind best glide, most of the time, e.g. taking off into some wind. Initially, while headed away from the airport, you don't want best glide because you do not want to maximize the distance travelled in that direction. As you come around to the tailwind part, best glide is lower than the no-wind number. But this only applies during the very initial, and final, segments, when you are wings level. Best performance is with a steeply banked turn, that will require higher than best glide airspeed to keep from stalling.
Bob - looking at my notes from that flight, and the data recorded by my laptop, it is clear that the throttle was at idle during the engine off testing. I agree that pushing the throttle to full would increase the pumping drag on the prop, and should result in a somewhat lower windmilling rpm, and a bit less windmilling drag. I did two test points where I stopped the prop, and for those I pushed the throttle forward. Even will full throttle and prop control full aft, it took me between 80 and 110 seconds to get the prop to stop, with the airspeed on the ragged edge of the stall with full flap (I couldn't get slow enough with the flaps up to get the prop to stop turning). And the prop would start turning again if I got faster than 85 kt.

My test results, with engine off and test results with engine at idle.
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RV-8
Moses Lake, WA, USA
http://www.kilohotel.com/rv8/
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  #13  
Old 09-07-2015, 06:22 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
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Quote:
Originally Posted by Kahuna View Post
Kevin is correct. In my practicing engine outs, I also found that my 6 cyl 2 blade metal, as it would bump to each next compression, about 3 seconds between strokes at 90 kts, at horizontal, my stall speed was ~15kts faster. It would stall my left wing and really catch your attention. This would happen as I neared the flare and would absolutely be a scary moment. My procedure is to hit the pavement, or what ever surface I happen to be landing on, at 80kts engine out. Anything less and I risk dropping a wing and crashing when the prop hits horizontal. Would be terrible to make a controlled decent to a nice landing, only to tumble and crash at the last moment.
Every departure, at throttle up, check altitude, add 1k', that's my turn back number.
Should that behavior be factored into the operational procedures of a 'normal' RV? At 80 kts in my -4 with wood prop, I'd miss the threshold at the *departure* end of most runways I fly from/to. :-) Stalling would never be an issue unless I decided to add a Top Gun move to the emergency procedures.

Charlie
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  #14  
Old 09-07-2015, 06:55 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Turnback

The guy from Oregon who writes a monthly column for Sport Aviation wrote an excellent article about this a couple years ago. RV8.
Sunrise Aviation at John Wayne airport teaches turnback to student pilots in Cessna 172. They have an excellent video of actual turnbacks to a simulated runway at low altitude.
Aircraft such as the Cessna 206 and 207 and the A36 Bonanza do not do well in the turnback. I tried it a couple of times in the A36 and found the performance to be horrible. Something in excess of 1200' just to do a 180, starting from normal climb speed. Piper Lance in simulated emergency landing takes 1200', gear stays up until base to final, flaps on short final. Pitts S1 will make it from 600' but the pattern has to be very tight. This is a 180 to land, not a simulated turnback.
There are many airports where one might not survive straight ahead. Lots of possible scenarios such as do you want to go in the water in cold weather.
Watching the Unlimiteds at Reno is a real education. They ALWAYS trade speed for altitude. There have only been a few off airport Unlimiteds at Reno in 50 years. Many more made the runway with no damage. Rare Bear must have been dead sticked at least 20 times over the years, maybe a lot more.
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  #15  
Old 09-07-2015, 07:16 PM
jrs14855 jrs14855 is offline
 
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Location: Lake Havasu City AZ
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Default Turnback

My 180 Pitts on takeoff from a 3000' runway would cross the departure end at 1000' AGL in near standard conditions. The most critical decision point in this case would be after the point where a landing could be made straight ahead on the runway-from that point to the end of the runway. After 800' AGL no problem.
Years ago I watched the same pilot make prop stopped landings in Pitts S1 from a very low altitude on two consecutive days. Base leg was approximately to the middle of a 4000' runway. Base to final turn was below 100' agl and turn was completed VERY low. A lightweight Pitts is actually a very forgiving airplane as long as one does not abuse the controls.
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  #16  
Old 09-07-2015, 07:47 PM
Smilin' Jack Smilin' Jack is offline
 
Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 873
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I am always amazed when I see charts for emergency proceedures. They are very good at giving us guide lines but you usually can throw them out in most emergencies. They are done in controlled situations. and can not take in all the conditional changes. Winds/ Temps. Pilot experience. Fixed pitch, constant speed. One plane has 30 degree of flap max another has 45. Both RV's
Each person needs to get with an experienced pilot/ Instructor and practice.. in various configurations. Then you' have a good guess at what might be a bad outcome.

One thing most pilots do not do is take winds into consideration when they take off. Any time you attempt a turn back to an airport runway should be done into the wind so you gain the benefit of a tail wind component on the turn back.

The other item and most students and pilots will hesitate... It is a big pitch change from an 90 mph climb out on an RV to a 90 mph descend and a 50 ot 60 degree bank which is required to get an RV turned around and headed back to a runway. Ask any Short wing Piper.... about a turn around.... the RV is in the same boat except the nose down/turn has to be almost instant.

If you practice enough you will get pretty confidant in a turn back... Better yet... go get a glider rating and really practice it.... from 200 feet. You'll be a much better pilot.

Rope breaks are required training in gliders...
You can turn an RV around well less than 600 feet.. but you must practice and when you pull on to the runway... ask your self everytime where is the wind... and which way will I turn should I lose it. be prepared...Practice. there are no acrobatic pilots who live without practice and lots of it.

Here is the delima on a nice winter day....
You want to impress the folks on the ground and do a short field takeoff climb out at 80mph and your 500 feet high AGL mid way down a 5000 foot strip... and you lose the engine... which is better... go straight ahead... or turn it around...? Try it..Then lets talk about it.

If you pass the threshold for landing at 500 feet AGL... How much runway does it take you to get the plane down.... into a headwind... Try it from the other end with a 10 or 15 mph tail wind. 3000 feet will go by really quick. What does Van say about slips with full flaps. What speed works best...? 75,70,65?


We all play with our aircraft... I have seen hundreds of RV's take off and hold it near the ground then zoom u p at the end of the runway... What then?

food for thought
Smilin' Jack
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Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
EAA690
APRS/ WB4JKY
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
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  #17  
Old 09-07-2015, 08:25 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,218
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Quote:
Originally Posted by Smilin' Jack View Post

Here is the delima on a nice winter day....
You want to impress the folks on the ground and do a short field takeoff climb out at 80mph and your 500 feet high AGL mid way down a 5000 foot strip... and you lose the engine... which is better... go straight ahead... or turn it around...? Try it..Then lets talk about it.


Smilin' Jack
S turn is my answer in this scenario.
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Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
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  #18  
Old 09-07-2015, 09:11 PM
johnf_1 johnf_1 is offline
 
Join Date: Nov 2012
Location: santa rosa
Posts: 68
Default 180

N95Jf has been my steed of choice since 6/86. She has had two power failures in that time, both involving stainless steel fluid hoses "guaranteed for life": the failure that resulted in a landing on the taxiway at Lakeport (and the bar there) en route to Van's is irrelevant. Relevantly, the engine did fail at or about 600-700 ft on departure on a warm day. I was able to do the 270/90 back to the take off runway with room to spare. The reality is at least RV4s are the kindest airplanes with so much excess performance...pity the poor souls who have similar experiences in 172s! Jim Ewing was an early adopter with an early H1...his 172 crashed in a canyon in the Sierras....you can imagine the H1 mindset...married to a 172 reality....not saying that is what happened, but it certainly is a possibility. John
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  #19  
Old 09-08-2015, 12:14 AM
rockwoodrv9 rockwoodrv9 is online now
 
Join Date: Dec 2011
Location: Meridian ID, Aspen CO, Okemos MI
Posts: 2,645
Default

Al, thanks for responding. It was nice meeting you at AV.

If I was at 1000', I am not confident I could do the turn. I have done it in practice but with everything else going on, it would not be my first thought. Maybe with more training and flight hours, I would take the risk. I know an off field landing is probably as dangerous as the turn, but I will be in control. If I stall, it is over. In some locations, turning back may be the best option and for sure the most convenient! The accident in Jackson Hole last year by a good pilot - probably better than I will ever be, makes me think real hard about dropping the wing to make a turn.

My plane is a tool to get me places - nothing more. I have insurance. My plane is worth a few tanks of gas - my deductible. For less than I spent on a bicycle, I will put it down wherever I think I can survive the best.

Quote:
Originally Posted by agirard7a View Post
Rock, would you risk a straight in off field landing
If you lost your engine at 1k agl? My point is turning back
May be a safer alternative if A, you practiced this manuaver and
B, you where at a min safe turn back AGL.
__________________
rockwoodrv9a
Williamston MI
O-320 D2A
Awaiting DAR Inspection
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  #20  
Old 09-08-2015, 12:36 AM
psyborgg psyborgg is offline
 
Join Date: Jul 2014
Location: Ft Worth, Tx
Posts: 6
Default Engine out

If the engine is not producing any power I would pick the nose up to stop the prop. I can assure you from experience that a windmilling prop or idling prop produces more drag than a still prop. While we always practice at idle, with the engine at a complete stop my aircraft was a much better glider!

If you have enough altitude to attempt a 180, I suggest a turn at 45deg and keep your airspeed up to account for the higher stall speed. What is much tougher situation to recognize is a partial loss, as when the cable for my carb heat broke and my O200 iced up just after takeoff. I made the turn back from crosswind after I finally realized I wasn't able to climb with the throttle full forward

I was curious as to the response to a wing dropping. Would not an opposite rudder input be more effective?
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