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cdtraver 05-02-2011 03:28 AM

ballancing
 
can a person put lead weight in prop spinner to help ballance plane

Insanemoondoggie 05-02-2011 03:33 AM

RE: ballancing
 
You can buy special weighted prop washers and weighted prop nuts. I beleive Dubro makes them.

CGRetired 05-02-2011 03:33 AM

RE: ballancing
 
You can, but how would you do it and keep the prop balanced?

They (Dubro for one) makes a weighted prop nut, a rather large brass thing, that replaces the prop nut that is on the engine.

The main issue with those types of weights is that if you should happen to lose one in flight, well, what do you do then? You have a tail heavy aircraft that can be difficult, at best, to land. The other disadvantage is that it puts an undue burden on the crankshaft bearings and bushings which can, eventually, harm them.

The best bet is to move things around as best you can.... move the battery as far forward as possible, mount the engine further forward, and so on, then add the stick-on weights to the firewall to make adjustments to your CG.

CGr.

goirish 05-02-2011 03:38 AM

RE: ballancing
 
Morning CG

I also use the heavy hub from harry higley-BTW, scrambled egg beaters, southwestern style, one slice of Aunt Millie's lite whole wheat toast and cup of green tea, Lost 23# to date. Got to fly one flight yesterday, first time in quite a while.

MinnFlyer 05-02-2011 04:15 AM

RE: ballancing
 
Putting weight in the spinner is a BAD idea for more reasons that I can list.

CGRetired 05-02-2011 05:42 AM

RE: ballancing
 


ORIGINAL: goirish

Morning CG

I also use the heavy hub from harry higley-BTW, scrambled egg beaters, southwestern style, one slice of Aunt Millie's lite whole wheat toast and cup of green tea, Lost 23# to date. Got to fly one flight yesterday, first time in quite a while.
Hey Irish. I did it easy this AM. I had a couple of wheat toasts, a banana, Tropicana OJ, and a cup of Dallmayr Coffee (German stuff.. really good!!). I'm trying to get some of this excess weight off my bod.

I used a heavy hub once or twice, especially on that Tiger 120 that needed so much nose weight, but I removed it in favor of more lead weight in the engine compartment. I just didn't trust one of those up there.

CGr.

opjose 05-02-2011 08:31 AM

RE: ballancing
 
To clarify

Putting in spinner weights = BAD IDEA
Putting in a weighted prop hub = NOT a bad idea.

The latter can fit under the spinner and mounts on the drive shaft.
They come already balanced, and the additional weight helps to keep your engine from dying out at idle.

Since you are putting weight in as far forward in the plane as possible, the increase can have more of an effect than forward fuselage weights.

However also consider trying to move your engine forward.

A .5" forward movement can be the equivalent of adding 2-4oz of weight to the nose.


Gray Beard 05-02-2011 08:49 AM

RE: ballancing
 
I have used the Higgly nuts quite often in my Bipe days, they work very well. I never did loose one but CG brings up a good point that I never gave any thought to. I have never had a back fire with a two stroke though and other then one OS 1.20 four stroke that's what I used them on.
Nothing for breakfast today but tomorrow my wood working club is footing the bill for the foreman and monitors at the Village Pub for breakfast. I'm not trying to loose any weight so I can make a pig of myself!!:D From there it will be a fly day at the field. Nothing in the way of wind is forecast and it should be around 90 and clear sky. Get to maiden the Cub I built for a friend too.[8D]

CGRetired 05-02-2011 08:54 AM

RE: ballancing
 
Hmmm.. breakfast sounds good!!! ;)

I have had a couple of pops that reversed the prop and unscrewed the prop nut, so I just don't use them. It doesn't happen often, and when it did, it was on the ground. I'm not at all paranoid, but I just prefer that little bit of edge up in the air that I don't have to think about the prop nut popping off in flight.

CGr.

goirish 05-02-2011 09:02 AM

RE: ballancing
 
I've never had a backfire in the air. Normally just when I am starting a 4 stroke.

Jim Thomerson 05-02-2011 09:18 AM

RE: ballancing
 
I've run heavy hubs on many engines and airplanes with no problem. I did put lead in an ED Racer spinner and it worked fine.

chocorrol 05-02-2011 09:22 AM

RE: ballancing
 
is it actually necesary to put the weight there? or to move the engine? I mean, wouldn't be easier and better to simply put the weight on the firewall?

opjose 05-02-2011 10:12 AM

RE: ballancing
 
A prop hub weight has a longer lever moment than adding weight to the firewall....

So you can use less weight on the nose, than you would on the firewall. It also improves engine performance at idle.

However moving the engine is an even better solution as it adds no additional "useless" weight to the plane.


carrellh 05-02-2011 10:14 AM

RE: ballancing
 
I have seen one plane throw the prop in the air, about 10 years ago. I 'assume' it backfired but am not positive. It was a big P-51 with a Saito 1.80. The pilot tried to bring it in but hit a light pole and destroyed the plane.

I have seen them thrown a few times while starting, which can be pretty scary.

chocorrol 05-02-2011 10:36 AM

RE: ballancing
 
but how much weight you could need to balance a plane? I don't think the extra weight would be too much to represent any problem

carrellh 05-02-2011 10:41 AM

RE: ballancing
 
When a 'balancing' thread comes up you'll sometimes see suggestions to relocate the firewall or wing saddle to avoid adding any dead weight to a model.
While I think moving battery packs around (we have attached them to the engine mount, or made holes in the tail area) is a good thing to do, I will not go to extreme measures.
I like to use long engine mounting screws and attach lead chunks to the engine mount rather than to the firewall but it's just a personal preference.

MinnFlyer 05-02-2011 11:02 AM

RE: ballancing
 
I'm with Carrel. Move things around a little, then add lead as needed.

tony0707 05-02-2011 02:41 PM

RE: ballancing
 
HI
relocating the battery can help-,-move the engine out on the motor mount as much as is reasonably possible-,if a tail dragger use heavier wheels,lead on the firewall-,balance-,slight nose down,-no fuel in the tank-and do balance left to right as well the plane will want to center its wing when flying level doing left to right balancing-BEST REGARDS TONY

chocorrol 05-02-2011 03:31 PM

RE: ballancing
 
ok guys, you are correct, the first thing to do is moving the batteries and rx arround, I assumed our friend was asking this because he already tried to move the stuff fwd.

JohnBuckner 05-02-2011 08:51 PM

RE: ballancing
 
1 Attachment(s)
Battery runs cooler and there is no vibration problem.

MinnFlyer 05-03-2011 04:47 AM

RE: ballancing
 
1 Attachment(s)
This is another way to do it.

bkdavy 05-03-2011 05:42 AM

RE: ballancing
 
If you have to add weight to the nose, you're not using a big enough engine! :D

Brad

CGRetired 05-03-2011 06:25 AM

RE: ballancing
 
Man, do I wish that were the case. I have a Tiger 120 that needed almost 20 ounces of weight in the nose. It has an OS 1.20 AX. What size engine would do the trick>? Whatever it would be, well, that would be quite a bit bigger engine, don't-cha-think? ;)

CGr

goirish 05-03-2011 06:29 AM

RE: ballancing
 
I think the Corvette 350 cross fire would be just about the right size. Not only that, it would run on regular gas, lots cheaper than glow.:):):)

JohnBuckner 05-03-2011 06:48 AM

RE: ballancing
 
1 Attachment(s)
For those times just weights are needed forward This variation on the forward battery box when used with measured amounts of lead shot works well:

John


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