12 Rubber Bands?

I have been building my first plane over the winter, a Sig Kadet LT40, and have it pretty much ready to fly. One thing that I am curious about in the instructions though is whether it is really necessary to mount the wing with 12 rubber bands. It really seems like overkill. Is there that much stress on them during flight?

Reply to
weeg
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On 30 Mar 2007 16:35:00 -0700, I said, "Pick a card, any card" and "weeg" instead replied:

Better safe than sorry. That's three fore and aft on each side and three each in a criss cross across the top.

-- Ray

Reply to
Ray Haddad

It's not

Yes

The other day at our field, a fellow pulled his trainer out of a dive. The rubber bands stretched, then popped off. The wing slowly fluttered to the ground, the fuselage didn't. He had 6 bands, 3 per side, on the plane. Way too few. As was said before, put the last 4 or 6 rubber bands on in a cross pattern. Right front to left rear and left front to right rear. The X pattern helps hold the others on. Just my $0.02 Paul

Reply to
42etus

The instructions of my first kit, the Goldberg Eagle 63, said to use no fewer than 14 rubber bands.

The object is to mount the wings rigidly to the plane. If you can move the wings, there aren't enough rubber bands.

Reply to
Robert Reynolds

I use 10 on mine. It really depends on the weight of your model. The larger or heavier you go, the more rubber bands you need. I would use what they suggested, more if you determine that they aren't enough.

Reply to
Vance Howard

You're gambling a few cents against a $200+ RC plane. Why be cheap about it? I have two Kadet trainers (small & large)and I use 12 to 16 rubber bands on them. You don't realize the force applied to the wing in a shallow dive or loop. There should be NO question as to the number bands. More is better, less could mean a costly CRASH.

Earl Scherzinger AMA #40329

weeg wrote:

Reply to
Earl Scherzinger

If you talking about #64 rubber bands then YES. As we have found on this NG there are rubberbands that are apparently much stronger and don't need as many to do the job. I'm thinking they are European super rubberbands. You can search this group on Google and find the thread. mk

Reply to
MJKolodziej

Dont know about the LT-40 but I had an Airmaster 40T that I didnt use enough gumbands on once. Whenever I would dive the plane would do the damnedest corkscrewloop. Turns out the front of the wing was lifting at high speeds. Needless to say I added more gumbands! On the other hand, I have a Speedy Bee ARF that I do not use the recommended amount of gumbands on. The recommended amount would either crush the wing or pull the fuse apart.

Reply to
Fubar of The HillPeople

Hey Daytripper: THAT was just plain cruel! (lol) Of course, the wing's AOA will stop changing when the wing departs the aircraft

In short, if they are #64 rubber bands, you need AT LEAST what the instructions call for. That wing has a very generous chord line, and that means there is lots of area to tilt into the relative wind when pulling out of dives. More area means more force and that needs the rubber bands.

Reply to
Six_O'Clock_High

On the other hand, if his field is in need of some entertainment, wait'll he sees how an LT-40 handles when the wing's AOA is constantly changing ;-)

/daytripper ("Look! Up in the sky! It's a pla - no, it's a flying yo-yo!")

Reply to
daytripper

Once you get the hang of building these things you can switch to nylon bolts and forget about your rubber band count.

Then of course you'll have to consider how big of a bolt to use. Most people use bolts that are too big, in my opinion....

Reply to
Robert Reynolds

Oh yes.

When I handed my cub over to the club president to test fly, he tried a spin, the wing lifted on its bands and snapped in half...

My last experience of glo planes..

You can pull up to 6-8g .. and all that goes through the bands.

It's an interesting debate as to whether you want the wing to snap before the bands break or snap because they stretched..;-)

Reply to
The Natural Philosopher

LOL

You must be talking about the proverbial 1/4-20 plastic bolt that the airframe always fails around to protect.. I generally use 10-32's because at least 50% of the time they fail and thereby protect the airframe from terminal damage.

Again, YMMV

Reply to
Six_O'Clock_High

"Six_O'Clock_High" > people use bolts that are too big, in my opinion....

--------------

A friend of mine had switched to using 10-32 nylon bolts in his pattern planes. Gotta save weight, you know.

After he lost his second Omen due to bolt failure after a few months, he went back to 1/4-20 nylon bolts and the problem ceased.

Myself, I don't like nylon bolts for models that are stressed heavily and flown a lot. I'll use metal bolts and take my lumps if I crash. Besides, when I crash, there's nothing usually left to salvage anyway. I do clean the area as a courtesy to our land owner.

Ed Cregger

Reply to
Ed Cregger

"Six_O'Clock_High" > people use bolts that are too big, in my opinion....

Now there's another debate, "build them to fly" or build them to crash? Nowadays I try to build for ease of assembly, unless it's small enough to leave the wing on. 6-32 cap screws and a ball driver IMHO work better than nylon 1/4-20 with any head. With my planes it's not a matter IF it's going to crash but when. mk

Reply to
MJKolodziej

Use at least 12 #64 rubber bands and of good quality (those made for model aircraft, are fuel proof etc,) throw them away every few months and replace. Also put them on from front to back so the most tension is at the wings front (leading edge). Helps keep the wing from lifting during flight as a few have mentioned. Wipe them off good at the end of the day and put them in a bottle or can with some talc to help absorb some of the oil out of the bands. Nothing wrong with using rubber bands, just requires and little forethought and maintenance. rick markel

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Reply to
aileron37

A small plastic container filled partially with kitty litter is a good place to store used rubber bands. The kitty litter absorbs the fuel and oil coating the rubber bands. Repeated use will tend to stretch and weaken the bands pretty quickly, however, so don't use them for more than a few flights.

At $1.75 per quarter pound, pay>> I have been building my first plane over the winter, a Sig Kadet LT40,

Reply to
Ed Paasch

On 31 Mar 2007 08:06:50 -0700, I said, "Pick a card, any card" and "aileron37" instead replied:

Months? I use mine for only one day. If I leave the plane assembled, I leave that set on until my next outing. Each flying day, I replace the entire set on the first flight of the day. Any that look the tiniest bit worried during the day get replaced as well.

-- Ray

Reply to
Ray Haddad

I agree use the cheap rubber bands all twelve and criss crossed for one flight and then dump them. They get fuel on them and with my LT

40 I love to put my plane into three or four loops just for fun. The stress is enough to just toss them away and go to Office Depot for a couple more bags. Doc Ferguson
Reply to
Doc Ferguson

I use 8 quality rubber bands and can do just about anything without fear of them breaking....and that includes vertical dives and spins with flutter. I have 300hours on my trainer and at least 80 club members who can attest to that with 8 rubber bands.

For a trainer, 8 is more than adequate. Naturally heavier aircraft may need more.

Reply to
The Raven

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