ululi1970

I am finishing a .60 warbird. The plan calls for just one 1/4-20 nylon wing bolt and I am wondering if this is enough. Or Should I use two bolts, maybe smaller (say #10)?
Thank you
Alberto

rafeeki

My Feedback: (11)

If you have 2 and one breaks you will have one left. If you have one and one breaks you have splinters....

Pay extra attention how thesocket/ blind nutis secured in place. Reinforce it anyway.

scale only 4 me

My Feedback: (158)

Put 2 if it makes you more confident,, but in my experience a 1/4-20 nylon is pretty stout,, I've never seen one break without the plane being destroyed around it.. The weak spot is the dowel at the leading edge,, I like to use two there also.

Problem with going smaller is they tend to strip out the slot or hex easier,, kinda a pita after a while

eddieC

My Feedback: (2)

I've never seen that size plane with just one 1/4" bolt, I'd recommend two 1/4". Find some nylon or plastic large-diameter washers to spread the load, I find some in plumbing supplies. 

KW_Counter

The purpose of using nylon bolts is so they will pop off in a crash.
The separation of main parts may lessen the damage on one or both of them.
I would go with the designers original plans.

Good Luck,
KW_Counter

ululi1970

I agree that the bolts are meant to break on impact to limit the damage to the wing/fuse. In fact, I saw it in action not too long ago. I will go with the design. Thank you
Alberto

prgonzalez

I had a 40 size plane with one bolt. It broke while flying. I still have the one good set of wings. The fuse came down as a misile, the engine broke on impact. The battery pack also broke, and the receiver was also damaged. If I had to build the airplane again, I will build it with two bolts.

Pedro

OldScaleGuy

My Feedback: (2)

I vote for 2 also. Not only adds some additional insurance it also snugs up the fuse on both sides helping to any gaps that may exist.

wcmorrison

My Feedback: (2)

 I had a severe crash the other day, it took out the wing mount block.  The block with its bind nuts and two nylon bolts did not break, the glue joint gave up the ghost.  The mount pin in front broke off, second time.  It is back on reinvorced.  I reglue the wing mount block and the plane is flying again.  Tough old bird.  I rather repair it and chunck it.  it is a Great Plains 60 sized Stik.

Point is 1/4 - 20  Nylon bolts are pretty tough.  Not good for landing gear but great for wings. 

If you are worried about a single nylon bolt just go down to Lowes or Home Depot and get a metal equivalent.

Rodney

Two 8X32 nylon bolts are more than enough for that size plane, 1/4X20 is over kill.

Gray Beard

My Feedback: (-1)

If you have two dowels then one screw is fine, if you have one dowel only then two screws in the back of the wing. I like to use two steel 4-40s with fender washers on my wing if I have one dowel. The plane I have on my bench now has no dowel but uses two 1/4 20s in front and one at the rear of the wing.
Going with the instructions is a pretty good way to go with a kit. Someone else did the testing and decided what was needed for you.

CK1

My Feedback: (60)

I have flown many 25% and 30% aerobatic planes that had only one 1/4-20 bolt for each wing .Never had any issues.
If the plans call for one bolt then one should be adequate .

dadragon

there is no such thing as over kill to keep what you build together and secure.

rrragmanliam

My Feedback: (1)

Sure there is. Too much overkill in a plane makes it heavy and a poor flyer.

rrragman

eddieC

My Feedback: (2)

I think this thread died when the OP said he's going with the designer's single bolt. Must work.

Airplanes400

My Feedback: (349)

Just because the instructions call for one wing bolt, does not make it a good idea. Remember, there are good designs and there are bad designs. Two bolts are better than one. While one bolt will hold the wing in place, it's not a good idea to use just one. All good "builders" find fault with kit designs (especially with ARF designs), and make adjustments and reinforcements where needed & necessary. The head can sometimes pop off of nylon bolts ... Rare, but it has happened to me. Due to age of the bolt, or vibration on weakened bolts that have 'stretched' due to slightly over-tightening after many times. Good thing I had two bolts on my wing when that happened!

ARF manufacturers claim their planes can be ready to fly in 10 hours or less! NONSENSE !! When someone builds an ARF in that short amount of time, their plane won't last, or will have mechanical difficulties. I reinforce the bulkheads, re-glue, fuel-proof, and secure flimbsy set-ups and control linkages on every ARF I build. My ARF planes don't crash, are reliable, built solid, and don't weigh a lot more after the modifications I do.

Remember, the manufacturer is not always right ... anyone can make a bad design. So, question the soundness of the instructions and make adjustments.

ululi1970

It looks like that jury is split between one and two. I can see good points made for either one. Safety in the air vs. limiting damage on the ground...
For the record, it is a Pica Kit, NOT an ARF. The wing has two dowels (well, actually horizontal plywood tabs that fit into slots in the fuse) and it is a single piece. I will start replacing the bolts on my other planes regularly, just to be safe...
Alberto

Iron Bottom

I always use 1/4 od aluminum rod or thin wall 4130 chrome moly tubing if the plans show wooden dowels. You won't break one of these babies. Plus, they can always be salvaged and reused to give those poor trees a break.

I also like aluminum bolts. There is not even enough weight to notice on the average .40-.60 size model. Nylon gets brittle as it dries out. Of course, nylon can be stored or boiled in water to retain it's strength. Not one of the things I want to do. Years ago, most flyers boiled their nylon props to make them last. Then, there are just poor quality nylon bolts available. I'll let someone else take this risk. If I was forced to use nylon bolts, I would use two.

bikerbc

The Idea of the nylon bolts is for them to shear in the event of an impact. I dont think Aluminum bolts would do that...I change out my nylon bolts every now and then when I see wear on them...I also usually use two....Using two dosen't add much weight...

rafeeki

My Feedback: (11)

I have a different slant on this discussion guys.
First its 2 bolts for me, no other way.

Nylon bolts replaced the rubber bands we used to hold down that wing with. Now if you wish to use aluminum thats up to you, but with either nylon or aluminum you will damage your wing in a crash, the nylon bolt doesnt save the wing. If you want the wing to pop off in a crash go back to rubber bands.

IMHO

MTK

Alberto,

Many years ago the same question appeared in a competition oriented column and there were at least as many answer choices in that discussion as have been offered to you thus far. What was missing was real test data on the actual strength of such bolts.

Since I had access to real test equipment, I took it upon myself to do the testing on the standard nylon bolts from the LHS Sullivans, Dubros, whatever. A single 1/4-20 nylon bolt connected at the threads and the head to the extension jaws of the test machine (Instron extensometer), started to yield at around 90 lbs force; that means it began to destort and stretch. It continued to stretch the threads upwards of 140 lbs force without breaking. I was as surprised as you may be at that finding. I stopped the test at 150 lbs of force. The bolt never broke at that much load but it was highly destorted. Of course there are all kinds of plastic bolts available today that come standard on ARF's from who knows where.... But I'd bet that if your plastic bolt was purchased from someone reputable, strength would be similar to that in the test.

A 60 sized model probably doesn't weigh more than 10 lbs. At 10 G's of accel the single bolt would see around 100 lbs force for a second or so and then the force would subside as the accel dropped. If your model is lighter than that it will withstand more G's on a single bolt. I stopped using two bolts on my 60 sized models back then since these hardly ever weighed more than 7 lbs.

Nobody sez you can't use more bolts if you want to...I'm saying it may not be necessary.... If landing gear is attached to the wing for example, two bolts are more insurance..

Iron Bottom

Most of the low wing designs are, shall we say, are captured in the fuselage by formers fore and aft. Mid wings, generally use some kind of wing tube. I just don't see a wing shearing off without affecting the fuselage. High wing flat bottom. Maybe. I once witnessed a Sig Kadet hit a steel light pole and shear about 1/3 of the left side of the wing completely off. It flew on and landed as if nothing had happened. What was holding that wing on? Rubber bands, of course.

Yes, I know 4130 tubing and aluminum bolts are difficult to break. I like this feature. I don't get upset after a crash, and I won't spend much time repairing a model either. To me, it's just time to move on. Too many interesting models out there.

Top_Gunn

My Feedback: (6)

Unless you are going to do negative-G manoeuvres, which you wouldn't normally do with this kind of plane, you don't need much strength in the wing bolt. All the bolt does in flight with this kind of plane is keep the wing aligned. Even if the bolt were to fail in flight, which it almost certainly won't do, the wing would probably stay in place. The lift that keeps the plane flying also keeps the wing pressed in place. So the bolt isn't subject to much stress. Planes with the wing on top or low-wing planes flying inverted are a different matter, to be sure.

Iron Bottom

That's true, Top Gunn. Another thing I didn't like was that a screw driver would cam out of the screw slot and usually ruin your nice covering job. But, if they do the job for you, good on you.

MTK

The nature of the question was general in reality. Many folks fly their planes in negative G and positive G maneuvers constantly entering one mode as they exit the other. Any rolling maneuver subjects the model to negative G, albeit usually only 1G.

Why not fly your low winger with no bolt holding the wing on and then report back?