hi guys

i was thinking of converting my yamamoto to use wing bolts instead of having to use rubber bands, i know that in the event of a crash the rubber bands will probably save the wing from damage but im not really comfortable to push the plane to its limits knowing that if i pull a few too many G's the wing may depart.

anyway, i have the bolts and everything i need to fit it, but how do i fit it? :S

I can't help you on converting but from first hand experience rubber bands won't save the wing. I was flying with an instructor I lost sight of it, it went below the trees, he took over and gave it ful power and it totaled. When I found itthe wing was in 2 pieces but the dowels were still attached to the rubber bands on one wing. I had put the recomended number of bands on it (12 I think) so I would not worry about losing your plane due to rubber bands.

Oh, it was a 60 size thunder tiger.

Hope that helps

Jon

Foamy,
First of all, if you use 12 rubber bands on the wing of that plane you're not going to be able to pull it off. Trust me here, if you pull enough G's to pull that wing off the structure of the wing is going to snap long before the wing pulls off.

Converting a wing to use wing bolts is more difficult than just drilling holes in the wing and putting some bolts in it. The front of the wing will need to have a dowel, or two, through the leading edge that MUST go back into the structure of the spar of the wing. This needs to be into the spar of the wing or it will pull out in flight. For putting the bolts in the rear of the wing you will need to pull the skin off of the wing and build up so that there is a solid piece of balsa for the wing bolt to go through into the fuselage.

While it can be done, I would recommend to not worry about doing it for your trainer. It's really going to be more work than it's worth. The rubber bands are more than enough to hold the wing on. Just fly this plane until you're ready to move up to your second plane.

Ken

12 rubber bands?!!

i have a hard time fitting 4 on there!! :O the dowels are only about an inch at most, i can fit 2 120mm bands going across the wing but if i hold the plane and shake it the bands stretch and dont hold the wing on, so i can barely manage to fit 2 80mm bands parralel over the wings

I agree that the rubber bands are sufficient to hold on a wing. I've had several crashes that resulted in the utter destruction of the airframe, but the bands held. I would use bolts if it was a scale bird or a speedster where the looks and drag of the bands would matter. Odd thing as I think about it, I've never noticed the rubber bands when the plane was flying......

You can easily replace the dowels with longer ones to fit more bands. A trip to any arts and craft store or Home Depot will fix you up. As a good point of order, I found it wise to carry extra dowels with me to the field, they can and do get lost and damaged from time to time and there is nothing worse than not being able to fly because of a $0.25 dowel.

If your plane is a 40 size plane you should be using #64 rubber bands. These measure 3 1/2" x 1/4". If you are using only 2 rubber bands to hold on your wing you are pretty much asking for trouble. Yes, these are not enough to hold the wing on in maneuvers. But a bigger worry is if you have a rubber band break in flight you are going to lose your plane.

For 40 size trainers you should be using ~12 rubber bands to hold the wing on.

Ken

Foamy, ya NEED more rubber bands laddy. A bolt-on conversion is something best done during the initial assembly of a kit. It is difficult to install all of the needed support structure INSIDE a completed wing without tearing it apart. You can do a half-butt (like that word change?) job but I wouldn't. Even for gentle flying ya need more rubber.

I'm pretty sure that diving any plane into the ground at full power will break the wings no matter how they're attached. But heck, I could be wrong.

an inch of dowell out of the fuselage is plenty. the rubber bands arent laid side by side all neat on the dowell. Instead its better if they're bunched up and over lapping.
I've flown plenty of trainers with rubber bands never came close to loosing a wing. however I have seen rubber bands break but with 12 you don't notice 1 break

This past winter I converted my LT40 to bolts, but I was also doing a complete refurbishing of my plane. I wanted the bolts for convience. I always used 12 rubber bands on mine and never had a problem. As to saving the wing; I think that if a crash is hard enough to break the wing, it's not going to matter how the wing is mounted. In both of my crashes the nylon bolts broke loose, but only on one did they save the wing. I don't think that should be a concern.

If you go to nylon bolts, use the proper size. 1/4 X 20's are way to large. With dowels in the front and two bolts near the trailing edge, 6X32 nylons are plenty for up to 60 sized planes. I only use 10X32 on my quarter scale planes and 8X32's on the 120 size. By using the smaller screws (and having no gap between the wing and fuselage) the smaller bolts will shear in side loads yet have an ample tensile strength for even serious aerobatics.

Putting two dowels into the front of a wing that wasn't designed to be held in that manner is often worse than it'd be to fly with 2 or 4 rubber bands. Very often, those dowels are going into balsa leading edge and nothing else. It's not a good idea. Not even close to a good idea.

If you want a dowel hold down, cut open the wing and build up the insides to distribute the stress out to at least the spar.

Best solution is to use 8 #64s or more.

The highwing in the picture below has flown since the 70s with an OS45 and 8 #64s. It's only got two on it in the picture because it was only slapped together for the camera. And that sucker has seen some TIGHT loops and some really hard charging. BTW, the wing is a scratch built. It's fully sheeted and painted with epoxy, so there has been no flex ever to absorb any flight loads.

BTW, put 3 rubber bands on each side straight front-to-back. Then put two on, crossing them. The crossing tends to keep all the rubber bands on the dowels.

an inch of dowel on each side is plenty

yes, an inch is more than enough, put five on each side and then do two across, these two across will keep the others on, and then with 12 that wing will break in half before the bands break,

Good Flyin

12 is the magic #.

My first crash during landing broke the wing in half, I think there was a few more than 12 rubber bands though. and after fully repairing the plane with fabric/epoxy reinforcement, the second crash into trees at full throttle popped the wing off and the wing was fine, still have to glue the rudder back on though.

i cant fit 6 on one peg, i dont know if you use different bands but mine are thick white ones and with one band on each peg it almost takes up the whole peg, i can fit 2 on each peg but its a tight fit and im not sure if they will pop off in flight, but i can only just fit 2 across and 4 along the wing (6 in total)

Our #64 rubber bands that everyone over here use look like this
http://www2.towerhobbies.com/cgi-bin...?&I=LXL435&P=7

if one band takes up the whole peg, those are the wrong ones

Ok here you go, i always put the first and last two bands going across, you can see they aren't very thick, i have twelve on there with room to spare

why those look like the bands i use to tie up parcels :S

the ones in using are big fat white ones about two and a half times as thick as those ones in acarter's picture but they are VERY strong and ive yet to have one snap, but am i using the wrong bands?

Yes, you are using the wrong rubber bands. You should be using the #64 rubber bands. And you should be using 10-12 bands on the plane to hold down the wings.

Ken

If you can separate your wing from your fuselage as easily as you say, what do you think??????? There should NEVER be a gap between the wing and fuselage except when the plane is in storage.

your instructor has not said anything about the rubber bands your using?no one at your field say anything.?

Good point aerowoof. What are the others at your field using for bands Foamy???