I purchased the Alpha60 ARF. ( not the combo! I purchased the engine and radio seperate ) I finished setting it up today and put it onto my GreatPlanes CG Machine and I need 4oz of weight in the tail. Even more if I move the weight forward from the tail. The engine and battery are as far back from the front as they can go. I'm lost at how I should go about adding the weight. Any ideas?

Pete

I really hate to add weight to a plane to achieve ballance so that is always a last resort for me. First, only because this is the beginners forum, I will ask if the fuel tank is empty? C/G is checked with the fuel tank empty. Also, what engine did you put on the nose that could be weighing it down so much? You probably would not be the first to put a 2 stroke .90 on a .60 size plane but that would obviously cause C/G issues in which case 4 oz. of lead would not be unreasonable. Also put the aircraft on your C/G machine at the point it does ballance and mark it and measure it and let us know how far off it is from the manuals specification. The C/G location is measured from the leading edge of the wing towards the back. This ballance point should be about 25%-30% of the wings chord (the measurement from the wings leading edge to it's trailing edge aka: front to back). for example if your wing measures a 14 inch wing chord 25% of that would be 3.5 inches from the leading edge and 30% would be 4.2 inches. Also if you can upload a picture of the plane ballanced on the C/G machine maybe we can see in it if there is anything you might be doing wrong and help you correct it. Good luck and congrats on the new plane.

Yes fuel tank is empty! The engine is the Evolution .61 the same engine that comes with the combo.

Like MrStang said, first make SURE you are balancing at the right spot.

Next, can you move the battery pack back?

I had to do the same with my Alpha 60 - 4.75 ounces of lead on the bottom of the horizontal, opposite side of the muffler. It's a big plane with a lot of wing, and 8 lbs. it won't notice the weight at all - mine will slow to a crawl on landing.

Hogflyer

I agree that while adding weight is undesirable, you could add a piano to that thing and hardly notice it

Just make a bay and hatch behind the wing mount former so you can mount the servos or battery pack back further.
But's it's an ARF and i'm not sure if you have all the tools.
it's simple if you have all the tools already and know what you're doing.

You can actaully just mount the servos to the back near the rear stabs like the bigger models. it'll give you better torque and less play.
If it bothers you that much.

While many models seem to always be tail heavy, others are notorious for being nose heavy. The Great Planes Big Stik 60 is one example. It's possible that the Alpha 60 is the same.

I cut a hole in the bottom of my Big Stik several inches behind the wings and mounted the receiver battery there. It's as far back as a 'flat' battery pack will fit in a fairly skinny tail section. A 'square' pack could go further back but I did not want to buy one at the time. I had to use a servo extension to reach from the battery pack to the switch. I secured the connectors using heavy duty thread (possibly dental floss) because I have lost a plane due to a connection like this coming loose. I just glued the wood back in place, rather than making a removable hatch, and ironed a patch of covering over it. It loks pretty good. It's on the bottom so you don't see it in the pits, and, it is invisible from 50 feet away. Even with the battery where I put it, I still needed about an ounce of lead weights under the tail.

That is exactly what I was thinking... Use an HD servo extension and move the battery back into the tail for balance. 4oz is too much to add on a plane this size for ballast alone.

As far as securing an extension cable so it doesn't come loose?
I use a short piece of heat shrink tubing that you can get at most hobby shops or electronics stores like Radio Shack and probably auto part stores too. Low cost, once shrunk over the connector it will never come loose until you cut the shrink tube off.

Have you thought about using a wood prop and a prop nut instead of a spinner? You may already have a wood prop I don't know. This may not get all the weight off the nose you need but it will help.
Also what kind of motor mount does that plane use? i have seen a few ARFs with heavy alum mounts. A glass mount would only be a few bucks and be lighter.

David

Another way to loose weight off the nose of the Alpha 60 is to take that flywheel off the hub, or just replace the flywheel/hub with the anodized blue hub Horizon sells for a few bucks.

Hogflyer

If your engine mount is one of those that clamp down on the engine mounting lugs make sure the engine is slid as far back as you can move it. Later on you can make it a tail dragger which will move the weight back a little more.
Fred

Why don't you just splice the wires and just solder them. This way you don't have to worry
about extra connections. A soildering iron is only $.99 at the $.99 store.

Depending on how you make a hatch..all you have to do is secure the pack to the hatch with tie wraps.

I mean..if you're pickiy like me...if I actaully had to add wieght..I'd probably cut into
the film and epoxy the lead on the inside anyway, to keep it all nice and purdy.lol

That's the ticket..... a tail dragger. This way you can add more wieght to the back and use those
scale tail wheels too

Thanks for all the tips. I got my plane balanced now and this is what I did.

I made an access panel on the underside of the fuslarge about 10 inches from the back . I placed my Battery in the access panel compartment and packed foam around it. That was not enough weight so I added 2oz lead weight in the compartment and she balanced perfect! Very slight nose down. The panel door is secured with 6 screws and I reinforce where I screw into the Bulsa with cherry hardwood. I painted the access panel and it look very neat and tidy. You cant see it unless you turn the plane upside down. And I have very easy access to add or remove the lead and battery.

Pete

Pete,

I balanced mine where the factory recommended, and found that I needed to additional lead in the tail to allow it to flair decently on landing. I haven't checked my actual CG, it's probably near the factory aft limit. The only way you can tell for sure by flying the plane.

Hogflyer

Good job Pete.[sm=thumbs_up.gif] Let us know how it flys.

david

can you show us some pics pete?

here is some pics

Looks good.
For future refference the farther away from the CG you put weight the less weight you will need.
It looks like you put the weight in front of the battery. If you had put it behind the battery you may have only needed 1-1/2 oz. All the way back to the end of the tail and maybe less than 1 oz.

hey nice job on your door in the rear of your plane ive been working on a alpha 60 the past month and im getting ready to install the engine fx 61 so i might have the same problem was wondering what you made your door from and how you cut it out on the plane also what engine did you choose? thanks for your time joe

Engine is the Evalution .61
For the access panel I just cut the covering with a hobby knife. The cover panel is made from Basswood. Its a little stronger then Bulsa. Its about 1/16 thick. I also used cherry hardwood strips and CA them into place to give the screws more to bite into.
I went to Walmart and in the craft area they sold 12" x 12" X 2" foam for $1.97 and cut that for packing.

I will not be able to fly her until May as I live in the Yukon ( Next to Alaska )