VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 09-29-2018, 08:55 AM
Plumbmaster's Avatar
Plumbmaster Plumbmaster is offline
 
Join Date: Aug 2017
Location: Concord, CA
Posts: 30
Default RV6A Loops 101

I'm looking for some step by step input for dong a loop in my RV6A. Powered by a 160 HP O320 with a constant speed prop but without inverted oil and fuel, I'm looking for the prop setting, entry speed, initial "G" pull, stick movement at various stages etc. I've joined the IAC and have made one acquaintance, but he's flying a different type aircraft, has inverted oil, fuel injection etc. Thus I would like to get some model specific input if possible.
The purpose here is to start a conversation about primary aerobatics only. This is not for instructional purposes and should not be used as such.
__________________
Ron Lem
"Stubbs"
1995 RV6A N89PC Bought In 2018
160 HP O320, CS Hartzell Prop
2018 Dues Paid
Reply With Quote
  #2  
Old 09-29-2018, 10:07 AM
titanhank's Avatar
titanhank titanhank is offline
 
Join Date: Aug 2007
Location: Friendswood, Tx
Posts: 221
Default

__________________
Rv-6
0-320/160hp
Dual pmags
Catto 3-blade gen 3
Smoke system
Glass panel
Autopilot
Flightline Interior
Almost rv14 seat mod
Reply With Quote
  #3  
Old 09-29-2018, 10:11 AM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,141
Default

Hi Ron,

To modify an old joke about high dollar purchases, "If you gotta ask, don't."

Seriously, don't try to teach yourself acro in an RV. At minimum, get someone who has experience to fly with you, or get instruction from a pro if you can afford it. Doing a loop in an RV is easier and simpler that a lot of other planes, but if you 'fall out' of a maneuver, the plane can overspeed much quicker than more traditional acro a/c. Years ago, a friend tried to teach himself acro in a homebuilt with similar performance and killed himself.

Having said that, I'll answer your question. In my fixed pitch 160hp RV-4, I do all the basic variations on loops and rolls starting at cruise power, and rarely if ever touch the throttle during a maneuver, even on the back side of a loop. With a c/s prop, the burden of throttle management is even less.

FWIW,

Charlie
Reply With Quote
  #4  
Old 09-29-2018, 11:53 AM
luddite42 luddite42 is offline
 
Join Date: Mar 2010
Location: USA
Posts: 393
Default

After some basic aerobatic training, your question will be self-evident even if you did not train in an RV.
Reply With Quote
  #5  
Old 09-29-2018, 04:03 PM
gottawork gottawork is offline
 
Join Date: May 2012
Location: Huntsville, TX
Posts: 124
Default

https://video.eaa.org/detail/videos/...autoStart=true
__________________
Lorne
RV6 IO360-A1A
Reply With Quote
  #6  
Old 09-30-2018, 04:48 PM
penguin penguin is offline
 
Join Date: Jan 2005
Location: England
Posts: 1,047
Default

From cruise speed, pull the stick back until only blue is visible outside.
Continue to pull until only brown visible, pull some more until the normal attitude is back. Stop pulling. Keeps the wings level.
If more detailed instructions are required take some training.

Initial speed is not critical, the amount you pull is. Modulating the pull as the picture changes from blue to brown is also important. Best way to find out is get someone to show you. Teaching yourself can be (very) unhealthy.
Reply With Quote
  #7  
Old 09-30-2018, 05:49 PM
RV8JD's Avatar
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 913
Default

Read Van's article, "An Aerobatic Epistle":

http://www.vansairforce.net/safety/A...ticEpistle.pdf
__________________
Carl N.
Arlington, WA (KAWO)
RV-8, 415 Tach Hours
(Pic 1),(Pic 2)
- Out with the Old, In with the New
(Pic)
RV-8, 1938 Tach Hours (Pic 1),(Pic 2) - Sold

Glasflügel Standard Libelle 201B, N564NS - Sold
Rolladen-Schneider LS1-f, N61MP - No longer owned
Reply With Quote
  #8  
Old 09-30-2018, 06:13 PM
luddite42 luddite42 is offline
 
Join Date: Mar 2010
Location: USA
Posts: 393
Default

RV acro is not special. Just get some training in a Decathlon and understand the RV is cleaner.
Reply With Quote
  #9  
Old 09-30-2018, 09:19 PM
gmcjetpilot's Avatar
gmcjetpilot gmcjetpilot is offline
 
Join Date: Jan 2005
Posts: 3,683
Default

Quote:
Originally Posted by luddite42 View Post
RV acro is not special. Just get some training in a Decathlon and understand the RV is cleaner.
I am not telling you HOW to do a loop. As luddite42 said, good advice, get some dual, understand before you start.

Second, there are things you should do and think of before looping your RV. You should start at 3000 feet AGL and practice stalls and stall recovery. Stalls (and spins) are always possible with a poorly executed aerobatic maneuver. Consider practicing stalls and doing steep turns to get your feel for stick force and G force.

Blue line or maneuvering speed is 134 mph. We are not doing abrupt maneuvers, just be aware. 180 mph is bottom of yellow, or smooth air speed. 210 mph is red line, never exceed.

A loop can be done easily at 3G's initial pull up. In fact all aerobatics in the RV can be done at 3G or less. Make sure your seat belts are tight and secure. With constant speed prop you can just set throttle and RPM and leave it. Fixed pitch prop may require some throttle use. Make sure your W&B are in CG and aerobatic weight. Make sure you are in an area legal for aerobatics (not on an airway), and clear the area for traffic...

A loop starts in level cruse flight (recommend start at or below yellow line 180 mph); you are +1G (straight and level), force pushing you in seat. Negative G is pulling you our of your seat (which you should not feel in a loop). We consider load factor "G" to be vertical, perpendicular to the wing in any attitude.

Initiate a moderate straight and level cruise (under 180 MPH bottom of yellow line) and pull up smoothly to 3G. (2.5-3.5 will work but beginning 3G is about right). Having a G meter helps. There is some significant stick pressure (like in a steep turn), but again don't over load and don't be abrupt. Blue line or maneuvering speed is 134 MPH.

Too little pull up you will run out of airspeed before getting over the top. Too much you are needlessly loading the plane and may have excess speed at the bottom of loop. As you go through the loop you will release the back pressure continuously, to make a round loop (not an egg shape).

At first 90 degrees look left and right out the wings to see your position in loop and make sure you are going straight (up). You may need a little rudder to keep from yawing and making the loop fall over to the side. This is your chance to get orientated. You speed should have bleed off to about 125 mph

As you reach the top of the loop, inverted 180 degrees from direction started, you have released most or all of the back pressure. At the top of the loop you will be above stall speed, say 70-80 mph (Vs = 59 mph bottom of green) and less than 1G. Anything over 0.0 G is positive. You want to have about +0.5G +/- . You want to keep some positive G. Some folks float over the top, adding some forward stick. Engines and fuel will be OK for a few seconds near zero G, I don't do that. Speed over top should be over stall with margin (and not too fast either). Again look out the wings, and look out top of canopy, to see your position over the ground; did you get off heading (typically you use a road to line up with)? Keep track of your progress through the maneuver and check your speed and attitude is as planned.

As you start down the back side you will feel the G forces built (and hear airspeed build) back up. You increase stick back pressure smoothly.... At the bottom you should be a 3G and same speed you started with (180 mph for example) and same altitude (approximately). You may even hit your own wake turbulence. Do not go over 210 Vne ever.... You will also be looking at altitude because you are trying to level off at entry altitude. At the straight down line look out wings and again see your position and heading.

Going through loop you see speed slowly decay from 180 to 70 mph for example, then build back on the back side. The initial 3G will go to 0.5 G over the top, back to 3G at bottom... If not doing another loop you release back pressure at the bottom, straight and level, going from 3G to 1G, and that is the end of maneuver.

It is way harder to explain than do. I start students doing 3G pull ups and then knocking it off and leveling off. Doing steep turns and getting warmed up for G's is a good start... As was suggested get some aerobatic dual. There are great books on aerobatics as well.... RV aerobatics are fun, easy and safe but it is serious business, so have a plan. However I say easy. To do a loop or roll is easy, to do them well, is very difficult and takes real dedication.
__________________
George
Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767

Last edited by gmcjetpilot : 09-30-2018 at 09:42 PM.
Reply With Quote
  #10  
Old 09-30-2018, 10:48 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 568
Default Aerobatic Epistle

Carl N, in which issue of RVator is Aerobatic Epistle found? John
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 10:37 AM.


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.