VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #81  
Old 11-25-2021, 08:28 PM
PhatRV PhatRV is offline
 
Join Date: Mar 2018
Location: Buena Park, California
Posts: 606
Default

The relative long runways worked out for him, 3400 and 4000 feet. From the video, he barely cleared the airport fence perimeter. I also think the airplane was light weight for the test flight. I also think it probably will not make it back at gross. However, there is a lot of flat terrain around the airport. It helps to have all the odds on your side.
__________________
RV8 standard build: Empennage 99% completed
Wing -- Closed
Fuselage -- Canopy Done. Fiberglass 80%
Avionics Installation -- 90%
Firewall Forward -- Cowl completed. Baffle 90%
Electrical -- 90%

Donation paid through 2022
Reply With Quote
  #82  
Old 11-25-2021, 09:39 PM
sblack sblack is offline
 
Join Date: Dec 2009
Location: Montreal
Posts: 1,520
Default

The way to optimize the turn back is to pull as close as you can to stall without stalling. Of course that is dangerous bordering on insane but thatís what the math says works. Lift is everything and drag is secondary. So unless you pull aggressively you arenít going to make it. Im not sure what technique was being used in these tests.
__________________
Scott Black
Old school simple VFR RV 4, O-320, wood prop, MGL iEfis Lite
VAF dues 2020
Instagram @sblack2154
Reply With Quote
  #83  
Old 11-26-2021, 01:24 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 1,023
Default

Quote:
Originally Posted by sblack View Post
The way to optimize the turn back is to pull as close as you can to stall without stalling. Of course that is dangerous bordering on insane but thatís what the math says works. Lift is everything and drag is secondary. So unless you pull aggressively you arenít going to make it. Im not sure what technique was being used in these tests.
Yep. Best glide speed goes out the window in the impossible turn. The size of the turn radius (i.e. distance flown) is what will makes the difference between making the runway or not. Unfortunately, this means flying a steep turn, near stall (think best endurance glide, not best glide angle) with elevated load factor. This is not the best safety recipe for low altitude flightÖ

Skylor
Reply With Quote
  #84  
Old 11-26-2021, 03:08 PM
swjohnsey swjohnsey is offline
 
Join Date: Nov 2018
Location: Kingsville, TX
Posts: 391
Default

You don't need to fly on the edge of a stall to make it from 500' in a RV-4. Engine out I aim for 90 mph, 45 degrees of bank or so. You can make your job easier by always setting up for a turn back by offsetting down wind (let any crosswind blow you off the center line once a rejected take-off is not an option).
Fly coordinated (no skids near the ground). Start your practice at 1,000 AGL and gradually work down to see what you are comfortable with.
Reply With Quote
  #85  
Old 11-26-2021, 04:44 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,644
Default Turnback

Quote:
Originally Posted by swjohnsey View Post
You don't need to fly on the edge of a stall to make it from 500' in a RV-4. Engine out I aim for 90 mph, 45 degrees of bank or so. You can make your job easier by always setting up for a turn back by offsetting down wind (let any crosswind blow you off the center line once a rejected take-off is not an option).
Fly coordinated (no skids near the ground). Start your practice at 1,000 AGL and gradually work down to see what you are comfortable with.
Finally someone who understands what I have been saying for a long time. In addition if you are in a side by side aircraft, in non crosswind conditions, immediately offset to the right (terrain permitting) so you will be able to keep the runway in sight on the left side in a climb.
The people who say that more than 240 degrees of turn is required are wrong. In my Wittman Tailwind the sink rate gets too high below 75 knots so that is my target speed.
Reply With Quote
  #86  
Old 11-27-2021, 11:05 AM
Jab Jab is offline
 
Join Date: Apr 2017
Location: Knoxville, TN
Posts: 90
Default

Interesting discussion and there may be some misconceptions. All things being equal, weight is not going to change the glide distance. You may have to change speed to compensate for a heavier aircraft and you wonít have as much time to figure things out, but you will end up at the same place on the ground. Wind will play an effect on this too but donít think you can glide farther just because youíre light.
__________________
Bought RV-4
KRKW
Reply With Quote
  #87  
Old 11-27-2021, 11:41 AM
PhatRV PhatRV is offline
 
Join Date: Mar 2018
Location: Buena Park, California
Posts: 606
Default

Quote:
Originally Posted by Jab View Post
.... Wind will play an effect on this too but donít think you can glide farther just because youíre light.
Thinking about weight. When flying glider, I get the better glide with more ballast. Given the low glide ratio of these short winged powered airplanes, the gliding distance won't be a factor. The speed will be higher for higher weight though, and it means higher energy at touchdown.
__________________
RV8 standard build: Empennage 99% completed
Wing -- Closed
Fuselage -- Canopy Done. Fiberglass 80%
Avionics Installation -- 90%
Firewall Forward -- Cowl completed. Baffle 90%
Electrical -- 90%

Donation paid through 2022
Reply With Quote
  #88  
Old 11-27-2021, 12:45 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,644
Default Weight

Quote:
Originally Posted by PhatRV View Post
Thinking about weight. When flying glider, I get the better glide with more ballast. Given the low glide ratio of these short winged powered airplanes, the gliding distance won't be a factor. The speed will be higher for higher weight though, and it means higher energy at touchdown.
Good to see someone who understands weight. Weight won't matter much, especially for the two seat and single seat EAB. In a jet airliner say in the 110k max gross weight range, max landing weight approximately 99k, weight with crew and min fuel 65k: At max landing weight the airplane from 30'000' to sea level will typically travel 90 nm in high speed descent. At minimum weight approximately 60 nm. Idle power, 300 kts indicated to 10'000' and then 250. Same principle in glider except the glider pilot plays a guessing game with lift. Heavier weight reduces rate of climb but increases glide performance.
Reply With Quote
  #89  
Old 11-27-2021, 12:51 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,644
Default Turns

There are people who discuss the turnback as a 90/270 turn. Charlie Precourt in Sport Aviation series on the subject states a minimum of 190 to 210 degrees of turn. The 90/270 has no place in this discussion UNLESS very unusual high terrain or obstruction is involved almost at the departure end of the runway.
Reply With Quote
  #90  
Old 11-27-2021, 01:27 PM
swjohnsey swjohnsey is offline
 
Join Date: Nov 2018
Location: Kingsville, TX
Posts: 391
Default

I'm not sure I would cherish landing in a crowded urban neighborhood. The takeaway is don't stall. If you don't make it back level the wings and land straight ahead at minimal speed. Generally, the stuff inside the perimeter fence is better than the stuff outside with folks there to give you some help.

Last edited by swjohnsey : 11-27-2021 at 01:32 PM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 05:20 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.