VansAirForceForums  
Home > VansAirForceForums

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

Keep VAF Going
w/a Donation






VAF on Twitter:
@VansAirForceNet


Go Back   VAF Forums > Model Specific > RV-3
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 03-07-2023, 06:18 AM
thinkn9a thinkn9a is offline
 
Join Date: Nov 2007
Location: Mississippi
Posts: 337
Default Runners can be useful

Runners are loops of webbing, with strength enough for climbing or tie downs, yet add almost no weight to your bag. ( available at REI etc.)

I have found the carabiners will not fit ( or easily fit) around the large tie down anchors found at many airports. The runners make it easy to connect, as you just slide it through and the clip the ‘biner through the doubled loop.
__________________
Wallace & Marietta Goodloe
9A -QB
N211LV
Phase 2 has started!
Thanksgiving time, is dues time for us
Reply With Quote
  #12  
Old 03-07-2023, 06:46 AM
Desert Rat Desert Rat is offline
 
Join Date: Aug 2018
Location: Wichita KS
Posts: 1,187
Default

How tiny is a RV3? I've never measured, but I find it hard to believe that most GA tie down pads would require you to have 70' of rope.

A 172 has a 36' wingspan and is about 25' long. The mental picture I have of one setting in the tie downs makes me think that most pad eyes are about 20' apart.

Combine that with the fact that RV's are low wings and it seems like 10'-12' per rope wing would be plenty, but thats just my mental impression, I guess I could be wildly off in my guesstimate.
__________________
Terry Shortt
AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
#72651
https://eaabuilderslog.org/?blprojec...t=all&listcat=
Reply With Quote
  #13  
Old 03-07-2023, 06:58 AM
MacCool's Avatar
MacCool MacCool is offline
 
Join Date: Aug 2020
Location: central Minnesota
Posts: 1,587
Default

Quote:
Originally Posted by David Paule View Post

Do not leave slack in any rope. The last thing you want is for the plane to move - in strong winds, that'll lead to rocking or bouncing and the dynamic overload will fail something. And the plane will be lost.

Dave

Juan Brown was talking about this relative to the latest snow storms out where he lives (4 feet of snow). He noted planes tied down at his local airport collecting enough snow on the wings and tail to exceed their negative G limits, made worse by how tight the wing tie-downs were...pushing down the tail from snow weight put even bigger lever loads on the wings that were tightly tied down. He predicts several of those planes will have been over-G'd from the snow load. Granted, not a consideration for most of us, but interesting to think about.

Knotting the tiedowns in the venerable old half-hitch manner is problematic with the Dyneema rope, for example, which wants to untie itself under load (not to mention less convenient). I'm looking around for ratcheting rope hooks like the NiteIze CamJam, but something stronger. In the meantime, I've been using some cam lock tie down straps and carry some soft loops for those occasional problematic recessed concrete anchors.
__________________
RV-9A, 2011, bought flying
IO-320D1A (factory new), C/S
Dual Pmags
IFR equipped
AFS 5400/3500, G5, IFD440 navigator,
bunch of other stuff
Reply With Quote
  #14  
Old 03-07-2023, 08:36 AM
David Paule David Paule is online now
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,635
Default

Quote:
Originally Posted by dstates View Post
For my current high wing airplane I purchased 15' long double braided nylon dock lines....What I like about a dock line is that it has a braided in loop or eyelet at one end.....
Nylon is probably one of the worst materials to use for tiedowns because the material is relatively stretchy. You'd need a large heavy diameter to make that satisfactory.

You can splice a loop into most ropes, by the way. Some splices are kind of fun.

Dave
Reply With Quote
  #15  
Old 03-07-2023, 08:39 AM
David Paule David Paule is online now
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,635
Default

Quote:
Originally Posted by MacCool View Post
Juan Brown was talking about this relative to the latest snow storms out where he lives (4 feet of snow). He noted planes tied down at his local airport collecting enough snow on the wings and tail to exceed their negative G limits, made worse by how tight the wing tie-downs were...pushing down the tail from snow weight put even bigger lever loads on the wings that were tightly tied down. He predicts several of those planes will have been over-G'd from the snow load. Granted, not a consideration for most of us, but interesting to think about.

Knotting the tiedowns in the venerable old half-hitch manner is problematic with the Dyneema rope, for example, which wants to untie itself under load (not to mention less convenient). I'm looking around for ratcheting rope hooks like the NiteIze CamJam, but something stronger. In the meantime, I've been using some cam lock tie down straps and carry some soft loops for those occasional problematic recessed concrete anchors.
The snow weight will off-load the tiedown rope's tension due to landing gear deflection.

The tendency of Dyneema not to hold a knot is why I prefer the covered ropes like Endura Braid, which do hold knots.

Dave
Reply With Quote
  #16  
Old 03-07-2023, 06:31 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 13,376
Default

Quote:
Originally Posted by Desert Rat View Post
How tiny is a RV3? I've never measured, but I find it hard to believe that most GA tie down pads would require you to have 70' of rope.

A 172 has a 36' wingspan and is about 25' long. The mental picture I have of one setting in the tie downs makes me think that most pad eyes are about 20' apart.

Combine that with the fact that RV's are low wings and it seems like 10'-12' per rope wing would be plenty, but thats just my mental impression, I guess I could be wildly off in my guesstimate.
Tiny, Terry!

Truth is that out here in the real west, tie-downs can be few and far apart. If you find them spaced twenty feet, you’ve found an airport with great funding and a manager with an attention to detail. More often, we will find very widely spaced spots filled with sand, and oftentimes, they are unusable, so you have to tie to the next one over. And the tail tie-down can be a long ways away….

I don’t carry that much rope all the time, but if I am traveling, its in teh bag (and not very heavy at small diameters…)

Paul
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #17  
Old 03-08-2023, 04:15 PM
Desert Rat Desert Rat is offline
 
Join Date: Aug 2018
Location: Wichita KS
Posts: 1,187
Default

Wow, I guess I'm lucky here in the midwest...Then again, we do have frequent 30 knot days and the occasional flying cow during tornado season, so tie downs have to be plentiful and robust.
__________________
Terry Shortt
AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
#72651
https://eaabuilderslog.org/?blprojec...t=all&listcat=
Reply With Quote
  #18  
Old 03-09-2023, 08:47 AM
rag rag is online now
 
Join Date: Feb 2012
Location: Holmen, WI
Posts: 67
Default

What is wrong with nylon stretchy rope? I would rather have the rope stretch when a wind gust loads the airplane to absorb the shock, than the shock transferring to the airplane (like a chain). The only thing I don't like about nylon is that it absorbs water. I don't understand the reasoning to not use a stretchy rope. Please explain.
__________________
Rick George
Reply With Quote
  #19  
Old 03-09-2023, 10:12 AM
David Paule David Paule is online now
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,635
Default

Stretchy ropes lead to the airplane rocking or lifting and dropping. Of course this only happens in violent wind, but that's when good tiedown performance is critical. When that sort of movement occurs, the dynamic loads tend to be higher than what a static loads analysis would suggest, and the higher dynamic load sometimes leads to failure.

Back in '81 or '82 I had an airplane tied down at the Boulder Airport in January. There was a windstorm. I went out to see how my plane was doing, and saw about a dozen wrecks scattered around. When I got there the wind was decreasing below 100 mph, and yes, standing or walking was difficult. They'd had various sorts of tiedown failures - ropes that slipped their knots, tiedown rings broken, loose ropes long enough that the plane could be pushed into another airplane, you name it.

I was an aerospace structural analyst and it was professionally fascinating to see all this and figure out what happened. I even saw some airplanes bouncing around like crazy, but surviving.

Here's another tip.... if you can tie a rope from a tiedown anchor to the landing gear, that will prevent the plane from crow-hopping sideways.

Bottom line - do anything you can to prevent rope stretch. I often double-up on my tiedown lines for less stretch, for example.

Dave
Reply With Quote
  #20  
Old 03-09-2023, 10:31 AM
Dan B Dan B is offline
 
Join Date: Mar 2006
Location: Edmond, OK
Posts: 230
Default

I use heavy dock line.

WINGS: 15'
Tail: 18'

I have found that to be adequate.
__________________
Dan Burdette
RV-9A, IO-320
Skyview, Garmin GTN750xi, TT Gemini AP
CFI, CFII, ATP
Guthrie-Edmond Rgnl, OK (KGOK)
________
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 06:57 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.