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Flying with or without wing tie down rings

magiccarpet

Well Known Member
Patron
A quick question to all flying RV-12 drivers. Do you fly with the wing tie down rings attached, or do you always remove them before flying?
What is best practice here?
Thanks a lot
Chris
 
I remove them. Probably not much chance that they would work loose and fall out but why risk it? Less drag too, although it wouldn't be noticeable. Should add that I don't often use them as my plane is nearly always hangared.
 
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I only tie down on rare occasions, so I install when needed and normally have them in the glove box. So far, in fact, I think I've only used them at Oshkosh. The rest of the time I just chock the nose wheel. I'm generally never parked outside fo the hangar for more than a few hours.
 
I'm one of the unlucky hangerless owners in SoFla. and tie down. I never remove for flight and do not see airspeed reduction or risk of loss in flight.
 
Once I forgot to remove them and accidentally flew several hundred miles in my Lancair with them hanging down in the breeze. I didn't notice any difference in performance, but did add "Check tiedown rings removed" to my preflight checklist.
 
I only remove mine at annual when I install hex head bolts as jack points to jack up one wing at a time for wheel and brake maintenance. I bought a tall hydraulic jack from Nortern Hydraulics and machined a cup on one end of a 2? OD AL bar for the jacking bolt hex head. I bored the other end of the bar to slip over the end of the hydraulic jack shaft. The AL bar is about 4? long. Works great.
 
Good Hint! Yes electralisis still exists!
Exactly

Including all nut plates.
All the other steel parts are coated, including the nutplanes and don't cause dissimilar metal corrosion.

Go ahead and leave those tie down rings installed and then try to remove them in a few years and report back. It will only get worse over the life of the airplane.
 
I see many that are concerned about corrosion live in some humid and wet environments. Out here in Phoenix with a hangar I haven?t seen any corrosion issues on my Cherokee (29 years here) or my RV-12 (6 years). However, I used to worry about glass transition temperature when I had a WAR FW-190 at summer air shows sitting on the ramp.
 
I see many that are concerned about corrosion live in some humid and wet environments. Out here in Phoenix with a hangar I haven?t seen any corrosion issues on my Cherokee (29 years here) or my RV-12 (6 years). However, I used to worry about glass transition temperature when I had a WAR FW-190 at summer air shows sitting on the ramp.

Glass transition temp?
 
Everything?

Yeah, everything is coated. Go ahead and believe that, if you want. What about the stainless firewall and all the aluminum rivets and angles attached? And how about those cad played bolts? You know, the ones where the cad playing is removed during the tightening process... Look at a standard washer that has been previously tightened. You will find the cad plating has been removed.

Point is, dissimilar metals are a fact of life. Preventing corrosion can be as simple as applying a light coat of grease or anti seize to the threads...
 
Doug,

The older fiberglass epoxies lost strength if overheated. The critical temp was called glass transition temperature, and 30 years ago people tried to avoid painting dark colors on the fiberglass so it wouldn?t sit in the sun and lose strength. In Phoenix we can actually fry an egg on a dark surface on the worst summer days. GTT was something you had to think about.
 
Doug,

The older fiberglass epoxies lost strength if overheated. The critical temp was called glass transition temperature, and 30 years ago people tried to avoid painting dark colors on the fiberglass so it wouldn?t sit in the sun and lose strength. In Phoenix we can actually fry an egg on a dark surface on the worst summer days. GTT was something you had to think about.

Still do.....
 
Aluminum Tie Down Rings

I will fly with my tie down rings

A_20_01.jpg


A_20_02.jpg


A_20_03.jpg


http://joesrv12.com/Builder Log/al_20_01.htm

Joe Dallas
 
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Nice!

Those are nice. Be sure to use a lubricant on the threads as aluminum/aluminum tends to gall pretty easily...
 
So no concern regarding the strength of those using aluminum? Shear strength if side loaded when tied down in a heavy wind? And there is a gap between the bottom of my threaded tie down extrusion and the bottom surface of my wing skin. Do you have a sleeve spacer around the top of the bolt?
 
Very very nice Joe. Much better look than those cheesy steel loops I got Lowe’s aviation supply. So...what would a fellow -12 builder have to spend to obtain 3 of ‘em? If you just want to “rough them out” then I’ll do the finishing and polish.
 
The OP question

I keep the wing tie downs in the map box and leave the tail one installed. It has saved some skin scrapes while loading on a trailer.
Hadn?t thought about the corrosion, now I?ll have to go look.
 
I took my tail tie-down ring out today. It's been in there for 7 years. I use it to ground the airplane when fueling as well as a tie down. I installed it with Loctite on half of the threads. There was no corrosion.

i-ngRKjsj-L.jpg


The shiny part of the threads is where I cleaned the dry Loctite off. I also ran a 3/8 X 16 tap in the aluminum hole and it went in with only light force on the tap handle. It came back out quite clean with no evidence of corrosion.

I consider it a non-issue.
 
Custom Parts

Thank Dave

My focus is finishing my aircraft and testing all the changes I have made to my 12.

I enjoy working on my Lathe and Milling machine.

I have had request for custom parts and I will make them for other builders after I finish my aircraft.

I will add a page to my web site and list the parts and drawings of custom Items available.

I will be starting my Jabiru 3300 Gen 4 engine soon and hope to be flying by November.

Joe Dallas







Very very nice Joe. Much better look than those cheesy steel loops I got Lowe?s aviation supply. So...what would a fellow -12 builder have to spend to obtain 3 of ?em? If you just want to ?rough them out? then I?ll do the finishing and polish.
 
Radius

I see no radius at the base of the threads it should have one there and another thing is the sharp root of the threads will be a weak point. If you notice the tie down ring shown it has rolled threads with no sharp root. Also if one uses a thread lube such as copper coat on the threads will take care of things.
 
Joe, in post #21, you link to this photo:

A_20_03.jpg


If this is a sample of your tiedown rings, please, at least generously (as much as possible) round the edges of the rope hole. Rope has decreasing strength when the radius is small. In that sense it's a bit like aluminum.

Dave
 
Details not in first post

There is a 1/4" at the end of the thread that is .374" and the hole in Vans bracket is taped to 1.5" deep using a 3/8" 16 Pulley tap and then Counter bored to 3.75 inches about 5/16" deep for the tail cone and on the wings they have a two step shank 7/16" 3/8" deep and the .374"1/4"deep to allow them to be in contact with vans Brackets and not contact the wing skins

Also I have chamfered the hole, However I use S hooks at the end of my tie down ropes


I see no radius at the base of the threads it should have one there and another thing is the sharp root of the threads will be a weak point. If you notice the tie down ring shown it has rolled threads with no sharp root. Also if one uses a thread lube such as copper coat on the threads will take care of things.
 
OK?

So still no radius at the end of the threads and the threads are still sharp in the root. Every one on here worries about stress risers in scratches which are the same. Not putting down your design just saying that its a stress point when side loaded.
 
Doug,

The older fiberglass epoxies lost strength if overheated. The critical temp was called glass transition temperature, and 30 years ago people tried to avoid painting dark colors on the fiberglass so it wouldn?t sit in the sun and lose strength. In Phoenix we can actually fry an egg on a dark surface on the worst summer days. GTT was something you had to think about.

Thank you!
 
Tie Down

With the angle less than 60° and the bolt is in a counter bore I can't see the loads needed to shear the 3/8" 2024 T3 Aluminum with a shock load from a tie down rope.
Also my aircraft is in a hanger 90% of the time.
I feel comfortable with this design.

Joe Dallas





So still no radius at the end of the threads and the threads are still sharp in the root. Every one on here worries about stress risers in scratches which are the same. Not putting down your design just saying that its a stress point when side loaded.
 
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Interesting Observation...

This thread ponders the the all-important question "Flying with or without wing tie down rings" and has 3,213 views and 33 replies.

The thread titled "Official Sensenich Propeller FAQ/Service Bulletin Revision B" only garnered 1,043 views and 6 replies.

Aren't folks worried about their props falling off?

Maybe its just the times we're living in...
 
This thread ponders the the all-important question "Flying with or without wing tie down rings" and has 3,213 views and 33 replies.

The thread titled "Official Sensenich Propeller FAQ/Service Bulletin Revision B" only garnered 1,043 views and 6 replies.

Aren't folks worried about their props falling off?

Maybe its just the times we're living in...

All RVs have tiedown rings. Only RV-12s are affected by the prop service bulletin. That's probably the reason for the higher number of views on this thread.
 
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The prop issue has some authoritative discussion from the manufacturer and an SB, while the tie down ring issue is open to discussion without conclusive evidence. That probably lends itself to more discussion.
 
Hi Joe,
We all fully understand your focus to finish and look forward to seeing your finished airplane!
Thanks,
Dave
 
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