RCKen

My Feedback: (9)

Wow, once again time as gotten away from me again. It's amazing how quickly things can get behind. I've been pretty busy at work, and around the building room I've been working on getting some projects finished up and moved out the door. Unfortunately, documenting this build got put on the back burner. It wasn't intentional, but it did happen. So, with that said, let me work on getting caught up. We are actually getting close to finishing up this project. What's left is balancing the plane, and then covering the plane.

With the plane completely assembled “in the bones� it's time to balance it. It's important to note that when a plane is balanced we need to make sure that the CG is in the correct location (this is balance from front to back), and just as important it to laterally balance the plane (side to side). Many people fail to make sure the lateral balance it correct and wind up with a plane that doesn't fly as well as it should . With a lateral balance that is not correct you will have a plane that will always dip a wing in flight. This can be corrected with aileron trim, but a heavy wing can also cause some weird things to happen when performing maneuvers. Spending a little bit of time to balance laterally will be rewarded with a better flying plane, so I encourage everybody to make sure it's correct.

Ok, let's jump in and start to check the lateral balance. The easiest way (for me at least) to check this is by using heavy (25 lbs test) fishing line. Very simply, we're going to use the fishing line to pick up the plane and see where it balances. Tie one end of the fishing line around the tail section of the plane (picture #1) and the other end around the shaft of the motor behind the spinner (pictures #2 and #3). As you can see in picture #4 set the plane level on your work surface with the fishing line attached ready to check the balance. Now pick up the plane using the fishing line. If you have a hard time doing it yourself get somebody to help you lift it. The trick is to lift the plane so that you aren't touching the plane at all. Looking at pictures #5 and #6 you can see that the plane is dropping the right wing. Before making any adjustments you may want to check your balance several times to make sure you getting a true reading of the balance of the plane. Since we know that the right wing drops we will have to add some weight to the left wing. This next step is why prefer to balance before covering the plane, because if we had the plane covered we would have to cut the covering to add weight to our wingtip. This way we can put it in place before covering. You can use anything you want to adding weight, but most hobby shops sell lead weight that has a self adhesive backing on it. Another great source for weights is your local tire change shop. They will usually save the old weights used to balance tires in a big can. If you go in and ask for them they will usually give them to you at no charge. The weights that I used here actually are sold for adding weight to pine car derby cars. Like I said, you can use just about anything. As you'll see in just a minute how you attach the weight becomes very important when you are adding weight. But first, find out how much weight you are going to need to get the plane to balance (pictures #7 and #8). Very simply, start placing weight on the tip of the left wing and check the balance. Keep doing this until the plane will now balance when you lift it up (pictures #9 and #10). As I said above, how you attach your weights becomes very important at this point. Why? Because epoxy adds weight. If you are using self-adhesive weights there won't be any added weight at this point, but if you use epoxy to put the weights in place you need to take into account the weight of the epoxy. Because of this you will actually have to put in a little bit less weight because the epoxy will make up the difference. Once your weight is in place recheck your balance to see if you got correct. Trust me, it may sound a bit difficult but you'll get the hang of in pretty quickly. Pictures #11 and #12 show the weights epoxied in place at the wingtip. Once final note here, you want to put your weights as far out on the wing tip as possible. If you try to put your weights in closer to the fuselage you actually have to add more weight to get it to balance than you will if it's placed at the wing tips.


Pictures
1. Attach the fishing line around the tail section
2. Attach the fishing line around the crankshaft of the engine
3. Attach the fishing line around the crankshaft of the engine
4. Set the plane level on your work surface.
5. Lift the plane using the fishing line
6. Observe the wing tips as you lift the plane
7. Use weights on the wing tips to adjust the lateral balance
8. Use weights on the wing tips to adjust the lateral balance
9. As you add weight to the wing tips recheck your balance until the plane hangs level
10. As you add weight to the wing tips recheck your balance until the plane hangs level
11. Epoxy the weights into place in the wingtips
12. Epoxy the weights into place in the wingtips

Until next time

Ken

RCKen

My Feedback: (9)

Continuing on with the balancing of our plane. With the lateral balancing done we now need to check where the CG (Center of Gravity) of the plane it. The instruction manual tells us that the plane should balance on a point 3-1/2� behind the leading edge of the wing. The CG on any airplane can be adjusted to better suit your type of flying, but when initially building and flying the plane you need to start with the CG at the recommended location, and then adjust the CG position later on. There are several different ways to mark where the CG is supposed to be, but for clarity I'm going to mark this on the side of the fuselage. In picture #1 you can see that I am using a straightedge to drop down a line from the leading edge position on the fuselage. From here I measured back 3-1/2� and marked the location (pictures #2 and #3). Now place the wing on the fuselage and transfer that mark to the underside of the wing on both sides of the fuselage(pictures #4 and #5). To check the location of the CG we need to now lift the plane at this mark and see if the plane balances. There are several different ways to lift and check the CG of the plane. In these pictures I am using the CG machine made by Great Planes, but you can get by without one. You can actually make your own setup fairly easily. Use two 1/4� pieces of dowel rod, 1/2� wood plank for a base, and two rubber pencil erasers. Drill two holes in the planking and glue in the dowel rods into these holes. Cut the dowel long enough so you can lift the plane up. Put the rubber pencil erasers on the end of the dowel rods. Now you can lift up the plane can set it on the dowel rods to check the balance point. You can also use your fingers to lift up the plane. Or have a friend help you, extend the marks for your CG out to the wing tips, and then each person lift the plane with one finger at the CG mark. A little experimenting and you'll come up with the method that you prefer to use. In pictures #6 and #7 you can see that I have placed the plane on the CG machine on the marks that I made earlier. The plane should rest left or just slightly nose down when it is balanced (picture #8).

I was pretty lucky on this plane as it did balance on the first try. But if it had not balanced we would have had to adjust the balance point of the plane. Usually you can get away without having to add weight here. Before adding any weight we can move the position of the receiver and battery to adjust the balance point of the plane. After moving these around the plane still isn't balanced then you will need to add weight, but most of the time you can get it to adjust just by moving these around.

In my next post I will put up more pictures of the plane being balanced.


Pictures
1. Using a straightedge to drop down the leading edge of the wing.
2. Measure back 3-1/2� to mark the location of the CG
3. Measure back 3-1/2� to mark the location of the CG
4. Transfer the mark to the underside of the wing
5. Transfer the mark to the underside of the wing
6. Place the plane on your balancer at the marks on the wings
7. Place the plane on your balancer at the marks on the wings
8. The plane should sit level, or just slightly nose down, when it is balanced.


Until next time

Ken

RCKen

My Feedback: (9)

I'm not going to go into a lot of detail on this post. I'm simply going to post more pictures of the plane being balanced. I'm showing these from different angles so you can see how the plane should look when it's balanced. As I said before, the plane should sit level or just slightly nose down when it is balanced. When the plane is properly balanced you should be able to leave the plane sitting on the balancer without worrying about it falling. For these pictures I left the plane on the balancer for about 30 minutes and in never moved during that period.

Ken

RCKen

My Feedback: (9)

For the next steps I do need to apologize because I don't have many pictures. Pictures of the sanding of the plane were lost when I had the memory card get corrupted, and unfortunately there is no way for me to reproduce it. So I'll do a written description of what needs to be done. It's not a huge loss though as sanding down the plane is pretty straight forward and easy to understand.

First things first, we need to prepare the fuselage for sanding. Many may wonder just what there is to prepare. What we need to do is fill in any dings, dents, holes, low spots, or anything else that just doesn't sit quite level. Trust me on this one, your covering material isn't going to cover up all of these holes in such. On the contrary it's going to make them stand out. So we need to spend a little time now filling them in. I'm not going to go into a huge discussion of each hole that needs filled, but rather there pictures show examples of what will need to be filled. You'll need to go completely over the entire plane structure and fill in any low areas. This would also include any low spots in the balsa itself.

Ken

RCKen

My Feedback: (9)

There are several different filler materials that you can use to fill in all of the spots on your plane. Your hobby shop (or Tower and the others) will carry balsa specific filling materials. Please note that there materials are among the most expensive out there, and there are others that are cheaper and do the job just as well or better. One substitute that a lot of modelers use is lightweight spackle which is available at Lowe's/Home Depot, Wal-mart, or any hardware type store. I myself prefer to use Elmer's Wood Filler. I feel that it's a bit lighter than the spackle, it spreads better, sands smoother, and is a wood color that helps it blend in to the wood of the plane.

These pictures here simply show what the spots look like when filled. You want to use as little filler as possible. Just remember, any extra filler on the plane is just going to have to be sanded off. So only use enough to fill in the low spot you are trying to get rid of.

Ken

RCKen

My Feedback: (9)

Sanding. Let's talk about sanding for a little bit. First of all, I absolutely hate sanding. There isn't any part of building that I dislike more than sanding. Whenever I have a build project stall it's usually at the point that I'm ready to sand the plane. Yuck!!! Now, with that said, there probably isn't any other step that can impact the look of the finished plane more than sanding. A poor sanding job can make and outstanding build look like junk, and a great sanding job can make a mediocre build look like a work of art. The covering is going to magnify every mistake in the finish of the plane, so please don't think that you can just cover up any “ugly� areas. So giving some extra time here can really pay off in the finished product.

Ok, a few words about where to sand. If you have a wife, girlfriend, significant other, parent, pet, or any other entity that you can get in trouble from where you live you may want to think about where you sand your plane at. When you sand the dust goes EVERYWHERE. And I mean everywhere. If there is even the slightest chance of you getting in trouble for making a mess you don't want to sand there, trust me on this one!!! Always wear a mask when sanding because breathing in that dust just isn't any good for anybody. If you have any electronics anywhere near, DO NOT sand there. The dust gets inside of electronics and coats everything making them run hotter, and eventually burning them out. It's also not a good idea to sand in the same room that you will be covering in. The reason is because you want all dust removed from the surface of the plane when you cover it, and trust me you're not going to be able to get all the dust off of everything. My best advice is to go outside and do your sanding. I have a sun room that I sand in, I NEVER sand in the house. I know modelers that take a lawn chair out beneath their favorite shade tree to sand. Wherever you want to sand, just make sure you can be comfortable and have plenty of ventilation. A good work surface helps too. I usually lay down a couple of old beach towels to put the plane on while I'm sanding. This helps protect the surface of the plane as you sand it down.

Ok, what are you going to need. At a bare minimum you are going to need sandpaper. 80 grit, 150 grit, 220 grit, and finally 400 grit is what you will need to finish out your plane. Like I said, that is the bare minimum, you can actually sand the entire plane with nothing but just the sandpaper. But there are several things that will help speed up the process. Sanding bars and blocks are very helpful. You can buy sanding bars and block, but you can also make your own if you are watching you budget. I simple block of 2x4 makes a great sanding block. Use some 3M 77 adhesive spray to attach the sandpaper and you're all set to go. While I said you can get by with just sandpaper, sanding bars will help you do a very professional job. The problem with doing it by hand with just a sheet of sandpaper is that it's very easy to sand high and low spots into the wood. But by using sanding bars you can sand an entire area level. Several different lengths are handy for final sanding the plane. 6�, 12�, 18�, 24�, and 36� are the sizes that I use. All of those sizes are available from Hobbico if you want to buy sanding bars. But an alternative is to be a piece of extruded “L� shape or “T� shape aluminum from the hardware store. You can then cut your own lengths of bar from this material. One final tool that really helps here is a Mouse sander made be Black and Decker. This can save you a lot of elbow grease. But a huge word of caution here, be very very careful with the mouse sander. It can eat through a lot of balsa wood in a hurry if you aren't careful. Because of this I usually don't use the mouse with anything less than 220 grit paper.

Before we sand we will need to completely strip down everything that we installed on the outside of the plane. Engine, spinner, control horns, control rods, or anything else mounted on the exterior of the plane need to come off before we sand the plane. I also like to take out everything on the inside of the plane like that can fall out while we sand. It's just easier to sand when you don't have stuff like the receiver falling in your way.

As I said, I am missing pictures of the sanding process. But it's pretty simple here. If you do have any questions about sanding please feel free to PM me to ask. The process of sanding is to make the wood surface level and smooth prior to covering. You'll want to sand the entire plane with each progressively finer grade of sandpaper. Large flat areas should be sanded with the sanding bars. This will let you sand them level. As you sand areas like this watch out for any low spots. You'll be able to spot them because the dust from sanding will collect in them. Smaller low spots can be sanded out, but don't take away too much wood. Most low spots should be filled with filler and sanded smooth.

Ok, this is going to sound a bit odd, but you'll know that they wood is ready to cover because it will have a smooth “soft� feel as you run your hands over it. If it feels rough, or you can still see the grain of the wood then you need to keep sanding.

Ken

b_man

Great Thread Ken, I wish That I had found it earlier I'm also building the LT-40 and have just mounted the tail feathers looks to be dead nuts on ,will try your digital cameras trick to check it. I don't like the way the wing sits on the saddle fuz did you have to make any adjustments there???
Barry

go-kartowner

Well Ken, You have just taken a good day and squished it into oblivion. If I have to fill every little hole, space, void, nitch. It will take me WEEKS!!! Now I will have to fill in almost every external joint on the whole plane due to loose fitting parts. Also I hate sanding. No, hate isnt the right word for it. I despise sanding. No, still not right. I DESPISE SANDING TO THE ENDS OF THE EARTH!!! Well now that my little outburst is over, sanding will also take at least a week of continuous work. Also if you have to carve fairing blocks, PLEASE save youfself now and buy the Great Planes razor plane. I wish now that I had. Check out my build [link=http://www.rcuniverse.com/forum/m_3992242/tm.htm]here.[/link]
Karter

RCKen

My Feedback: (9)

go-kartowner,
Sorry to ruin you day!! Actually filling and sanding doesn't take too much time. You can fill the entire plane in 20-30 minutes. I despise sanding too, so I know how you feel. But on the LT-40 I think I only had to spend about 2 hours max sanding it.

I've got one of those GP power planers, and it's still hanging on the wall of my shop. I don't use it. The problem is that it eats too much wood at too quickly. I use a hand plane and I feel that I have better results.

Ken

bruce88123

I think he meant the hand razor plane Ken. That is what I recommended to him in his thread. I also have the power plane and I put it back in the box too. I agree that there are few applications for it in my world. Hand plane=Good, power plane=overkill IMO .

And Karter, just don't put on too much filler so you won't have to remove the excessive amounts.

go-kartowner

Are we both talking about [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXAA64&P=7]this[/link]? BTW it is a MAS razor plane, not GP.
Karter

Arghhh... bruce posted while I was typing. I thought ken and I may be talking about different things and yes it is the one bruce reccomended to me.

RCKen

My Feedback: (9)

That's the one!!!! That's exactly what I use. I prefer that over the power planer from Hobbico any day of the week!!!!

Ken

bruce88123

And just so you will know what the other one we were talking about is Karter.

http://www2.towerhobbies.com/cgi-bin...?&I=LXAEY2&P=7

I just haven't found a good application yet. That said, I'm sure there is one somewhere.

go-kartowner

Ahhhh...Well, you could use it in scratch building, carving one piece balsa wheel pants out of those big blocks. Getting rid of those nasty callouses that old people get on their feet (thats really the reason Bruce and Ken have them, they just don't want to admit it) Those are a few of the many reasons to get one that I can think of. (Just thimk of how happy the old people will be when you get to the nursing home the remove their callouses!)
Karter

RCKen

My Feedback: (9)

I still use the hand plane on big blocks of balsa too. In fact, I'm working on a Dynaflight Super Decathlon and the wingtips have to be carved from 3"x3"x18" blocks of balsa. I still left the power planer on the shelve and used the Master Airscrew hand plane to get the job done!!!

Old??? Then you must be referring to Bruce, but not me!!!!

Ken

bruce88123

Hey -hey , That's enough of that. He means MinnFlyer or Bubba, not us. Besides I can't get to my callouses with it because my bunions get in the way. Does Great Planes have anything that works well on hang nails? Gotta have a power cord on it though. [sm=bananahead.gif]

krossk

My Feedback: (27)

That's what the thicker blades for the Slot Machine are for! Besides, I thought the problem was bending over to reach your feet...[sm=bananahead.gif]

bruce88123

You been watching my web cam again?

maineac58

I am assuming that the plane. etc has been delivered by now. Have there been any posts and pictures of the proud owners?

RCKen

My Feedback: (9)

It has been delivered, but I haven't received any pictures yet. Seabee promised a video of the girls flying it. I'll post that as soon as I get it myself.

Ken

jeff1127

I'm new to the hobby and new to building and I have to say the work you put in this build thread is AWESOME!!!
And the fact that you did it for someone so deserving makes it even sweeter.

I'm building a Goldberg Eagle II and the tips you have included will certainly help me.

Others have said it and I want to add my appreciation for all you've done. You are one of the finest examples of the good people to be found in this hobby.

bruce88123

The basic building techniques demonstrated in this thread apply to virtually all kit building. Variations will occur of course but the basics never change.

Most importantly:
Read the instructions thoroughly.
Trial fit all components before glueing.
Take your time.
Expect small errors and don't let them get to you - compensate or correct.

maineac58

Still no pictures or posts from SeaBee???? Has anyone heard anything from him at all?

RCKen

My Feedback: (9)

He called me a few weeks ago. He's had some medical procedures this summer that have kept him from getting out and trying the plane yet. But they got it in one piece. And he's promised me pictures and video of the flights when they get out and fly it. I'll definitely post them when I get them.

Ken

maineac58

Ken,
OK Thanks, being as I am also fom Maine, I wondered if he might have had some more medical problems.
Would actually like to meet him and the family at some point.

Thanks again

Carl