scooterinvegas

My Feedback: (1)

One of my planes balanced 1 3/4" behind my CG, and the amount of lead behind the firewall was higher than I was happy with. When I hung the weight on the end of the prop shaft, it was all most half the weight. So.......

I melted down a couple of lead tire weights and pored them into the aluminum nose cone, drilled a hole in the lead the size of the cone center bolt and balanced it. Now, I was thinking about gluing the lead slug into the nose cone and then re-balancing. But I started thinking, what glue will stick to lead. I drilled some "pinning" holes in to the lead for the glue to bite into. Will that be enough?

I'm also concerned about the forces generated on the glue/lead being that is directly connected to the crank shaft.

With the cone adapter and bolt going through the nose cone, the lead really cant go anywhere. It not like if it came lose, it would/could move over to one side causing the engine to be throwing extremely off balance.

What do you guys think?

Its a 10lb, 120 size plane with a 4 stroke glow engine.

Scoot

blikseme300

My Feedback: (118)

Scoot,

I would not do it. I would rather bolt a balance weight as far forward on the engine mount as possible.

I once had a heavy brass prop nut that fitted inside the spinner on a Surpass 120 to do the same as what you are wanting to do. CG worked but the engine ran erratically untill I did away with the heavy nut. I think the flywheel effect was just too much for good running.

Bliksem

JohnBuckner

My Feedback: (1)

I have an aversion to adding ballast to rotating components.

Much prefer a ballast box directly behind the propellor and within the cowl if there is one. Placing either a flight battery pack in it or failing that lead shot.

John

sensei

If your C/G is really that far off then you must be adding allot of lead. There is no way I would add that to my spinner. Is there anything you can do to reduce the weight of the airframe from the C/G aft?

Bob

LesUyeda

There used to be Higley "heavy hubs" that were brass prop nuts that added a couple of ounces of weight to the end of the crankshaft. As long as everything is balanced, there should be no problem.

Les

scooterinvegas

My Feedback: (1)

It's 4 1/2 oz in the spinner. I was thinking the fly wheel effect might have adverse effects. I thought I would ask here first. I will just add the weight the the motor mount. Thanks.

beepee

Good move. Anything disturb that 4-1/2 ozs from center (like a bad bump from the starter) and you could have one mighty missile on your hands.

I hate tail heavy!

Good luck,

Bedford

Avaiojet

Altering the spinner, by adding weight inside it, and your opening yourself up to liability.

People do get injured in this hobby, when modelers don't think.

Especially when injury, to others. is the last thing on their mind.

I'll tell you about weight.

Yes, for a model to fly properly, it must be balanced on the required CG for that model.

As far as what it weighs, it doesn't matter, when it's completed, IT IS WHAT IT IS!

Only during the process of building, can weight be considered. And when it's considered, how much weight can you really save?

I've never weighed a model airplane in my entire life.

sensei

Lets see, IT IS WHAT IT IS, only if you are willing to except that... During the process of a build, weight should always be a consideration. How much weight can you really save? I have a little experience with this so here we go. On a 40% aerobatic plane, between 10 and 14 lbs. 35% aerobatic plane between 7 and 10 lbs. 33% aerobatic plane, between 6 and 8 lbs, and a .32 glow size sport plane, as much as 3 lbs. this is not an assumption, it has already been done with proven results, and the flight character and performance improvement is overwhelming. You have never weighed one of your models, I guess all I can say is, that is really too bad, because the ease and joy of flying an airplane with really light wing loading is unlike anything else...

I almost forgot, aerobatic aircraft in the 52% to 55% range, between 25 and 35 lbs.

Bob

jester_s1

I'm glad you decided not to put lead in the spinner. At 10,000 RPM, the centrifugal forces would be immense.

Can you move anything forward? Your flight battery and sometimes servos can be moved, which not only adds weight forward but removes it from the back. Lighter pushrods for your tail can make a difference too.

scooterinvegas

My Feedback: (1)

Holy crap are you HIGH and MIGHTY.

I was asking for input on the use in question. Not about my ethics or intelligence.

A 10lb plane going 60 mph with a 16" prop spinning 9000 rpm, and 4oz in the noise makes me irresponsible?

To everyone else, thanks for your help.

scooterinvegas

My Feedback: (1)

This is the answer I was looking for. Now that Ive had a day to think about it, I don't want to effect the way it runs. That is too much weight to add directly to the crank of such a small engine.

Is far as mounting, I decided a big NO on glue. Remember, I poured the lead into the nose cone using it as a mold. Thats still is not safe enough. If the engine performance was not an issue, I would still do it but I would tig weld a plug in the end of the cone and re-pour the lead in through the rear hole. Re-drill on the mill and balance. That would make it SOLID. It could not move, rattle, expand or come lose. That is a moot point, because I would not want all the weight (inertia) added to the prop. Im done with this thread.

Again, Thanks for your help.

scale only 4 me

My Feedback: (158)

I don't know what plane were talking about here, but have you seen this as a option to get weight as far forward as possible?

http://www.rcuniverse.com/forum/m_98..._1/key_/tm.htm

good luck