eaglelope

You are too kind... really. My covering skills are fabulous, as long as you are more than 10 feet away from the plane.

Two weeks ago I had my Chippy out for her second weekend. After the maiden flight jitters I had a day planned of trim flights and fun. I had a nice smooth takeoff, turned out and flew the pattern once. OK so far, so I did a nice big loop. At the bottom of the loop I heard a loud pop and saw something flittering down.

I still had control so I brought her by to see if I had lost wheel pants, wheels, canopy, whatever. Nope... everything wa in place but the plane just didn't seem stable on the roll axis. I carefully turned out to set up for a landing. As I did, I noticed that all of the covering on the top right wing panel had ripped off.

I was able to bring her in without so much as a scratch. It's nice to know you can fly with 3/4s of a wing.

I got more practice at recovering the wing and every seem got a re-heat. One day, I will really learn how to cover.
Mark

RVM

The covering ripping off made that loud pop? That's interesting. How on earth did this get ripped off suddenly enough to make any noise at all?

You know, there could have been some chipmunks hiding in the grass with some anti-aircraft pellet guns and that might have caused it...

hah ok bad joke ignore that...

I hope you get your plane back in the air soon.

By the way, how much did your plane weigh in at?

RVM

Ok, got started tonight. Yay!

Here is a picture of my new, smaller work area. The bench is a 2'x4' folding buffet table with a particle board top. It is perfectly flat. On top of that I have a sheet of 3/4" MDF, which is also perfectly flat. For a surface I have a sheet of Celotex. I hate the material, but unfortunately it has proven to be the best surface to pin things to. It holds onto pins well and stays flat.

I laid out all the parts on the floor to take inventory. It's all there.

What would I do without my Box-A-Balsa? rawr!

I took all the sheeted parts (ribs, formers etc.) so that I could sand them while they were still in their holders (forgot the correct term for the wood that the part was cut from hehe). I used 240 grit sandpaper on a 5.5" and 11" Great Planes aluminum sander. This isn't heavy sanding; I sanded just enough to smooth things out.

RVM

These are my excess glue removal tools. The red tube is just a piece of Sullivan Nyrod tubing that I cut at an angle to make a sharp point. You can neatly scoop glue with it. A small bamboo stick cut the same way works just as well, but I find the plastic to be easier to clean. The yellow thing is a tiny spatula I got from Lee Valley. I got a pack of like 6 of them in different colors and they are extremely useful. I use them to apply small amounts of filler, spread out glue, take up excess glue, squeegee glue and numerous other tasks. It's on one of my small cutting boards/weight distribution tools (very advanced!), which is a piece of 3/4" MDF.

Here are some pictures of needles and syringes I also got from Lee Valley. I got two packs, and there are 5 syringes in each pack. They also come with something like 5 or 7 blunt tip needles in various diameters from around 22ga. to 18ga. I don't have a picture of it, but there is also an accordion type syringe/applicator thingee and it comes with 16ga. tips. I find the 20ga. and 22ga. to work best for Titebond. The filled syringe is in a cup of water so the glue doesn't dry. You can also see my vat of "T" pins.

Just another picture of a few other tools I use a lot. The Fourmost Miter Sander is great for making perfect angles. I just cut trusses and whatever else oversize, and use that to sand it to the perfect fit.

eaglelope

Not certain about the weight, I don't have anything other than bathroom scales at the moment. Taking the diffenrence in weight with me holding the plane and not, it looks like 7 pounds. I'll try to find something with a little better accuracy.

If you look at the leading edge of my wings, you'll see that they are red. I originally covered the whole wing in white Monokote and planned to paint the leading edge with LustreKote (bad idea). I trimmed off the ugly results and covred the LE with Metallic Red MonoKote that overlapped the white by about 1/4". The seam faced away from the slipstream.

I must have not ironed the seam down very well on the right wing panel because the white came up from under the red and was instantly ripped off in the slipstream. The red trim on the LE was stilll intact with no residue from the white that was underneath it. I gotta blame that on my poor workmanship. That sudden ripping was the pop/swoosh/flutter sound I heard. I like the ack-ack Chipmunk explanation better though.

I got her covered again (cutting stars in blue MonoKote is getting old) and back in the air last week. So far, so good....

Mark

RVM

Construction begins.

Here is the first step - creation of the little sanding tools. I used medium Handibond CA for this. It didn't want to bond the joints very well, so I'm guessing this glue is going bad. The parts didn't come together perfectly square, but I do not think this will affect the sanding. I'll test the tools on some scrap before I use them, and if they don't work I'll just make some replacements.

Here you can see the horizontal stab framed up sans the trusses. There is a small problem here. The center support piece doesn't quite fit. No problem, I'll just trim a piece of balsa to make up the difference. With enough glue this should be plenty strong enough, especially considering this whole stab is going to be sheeted.

Not everything aligned correctly to the plans, so some of the trusses don't exactly line up as intended. Also you may be able to see that the sticks are inconsistent in their size, as are the other parts for the tail. After carefully measuring them, it all varied by as much as 1/32" - 1/16". It's going to take a good bit of sanding to even the surface out. I think the whole horizontal stab is going to end up 1/16"+ thinner than intended, not a big deal, hopefully. The horizontal stab is framed up minus the sheeting.

I did the same basic construction for the vertical stab and found the variance in stick proportions to be quite less. I finished framing up the vertical stab, but again, found that one of the parts didn't quite fit. I sanded it down and squared it to receive a scrap piece of balsa, which I fit into place. This part should work out fine.

RVM

The last thing I did was build the balances for the elevators and the rudder. These are laminated balsa, which I did with aliphatic glue. To prevent warping and get a good bond, I put the parts under a fair amount of weight with solid, flat surfaces on the bottom and top. I used a sheet of wax paper underneath and folded over the top to keep any glue that might seep out from sticking to the MDF.

That's about all I was able to get done. The glue has to fully cure before I can sand the parts down to be ready for sheeting anyway.



While most of the wood in this kit actually seems to be quite good and appropriate (light balsa for sheeting, heavier balsa for ribs and doublers etc.), I am disappointed so far because of the very inconsistent sizing of the sticks and, to a lesser degree, the central supports for the horizontal stab. Also the fact that some of the parts didn't line up with the plans, or with each other, was irritating. I hope this is not something I will have to deal with throughout construction.

RVM

Man I just hope I can stay down around 7lbs.

I can see how that might have made a loud noise. Your plane still looked great. Wanna cover mine for me?

RVM

I was right concerning the amount that would need to be sanded to get all the parts even. The unsheeted horizontal stab ended up being only 1/8" thick and still isn't right. The vertical stab is not much better. I'm going to go pick up some replacement sticks and cut out the laser cut support parts from sheet balsa. At least this way I can make the parts to actually fit the plans. The sticks should only be a few dollars and I already have the sheets that I would require. Good thing I'm not in a hurry.

Hopefully I won't have to do this on anything else...

eaglelope

Looking good so far. As I recall, one of the things that gave me fits was sorting out all the stick sizes. I think there were at least hald a dozen differnt sizes and some were very difficult to discern by sight alone (of course that was about the time I had to switch to bi-focals too... ). Not sure if that's what you're runnin ginto on the stab or not but thought I'd mention it.

My kit had some wood problems too. One of the pieces of aileron stock was as hard as a rock. I couldn't sand it or slot it with anything. I actually bent one of the Dubro hinge slotting forks on it. You might check that in case you need to order any replacements.

I took mine out again today and I'm really liking this plane. I think I need a little more right thrust but the plane already flies better than I do. I tried my hand at doing a blender today (sort of a vertical diving roll to inverted flatspin kind of thing) and the Chippy did pretty well for a non-3D bird. She's very forgiving. Here's a few pics from my camera phone.

RVM

You've got a really good looking bird eaglelope.

I was wondering how well a Chippy could do a blender. It's one of my favorite maneuvers.

I may call Goldberg tomorrow and make them send me some new parts. In the meantime, if I'm not too busy, I'm going to go ahead and start on the wing. I'm going to double check the spars and whatnot though, and instead of trying to work with bad materials, if there are any, I'm just going to replace it from the beginning.

RVM

Alright, I was able to start on the wing tonight, sort of. I got as far as checking all the ribs, which are cut from good quality balsa. I glued on the doublers to ribs 3 and 5 of both wing panels. Good thing I use aliphatic, as on the first doubler I accidentally glued it on upside down. hah!

3 of the spars were warped, from very mild to fairly bad. I took the straight one and pinned it down, and wet the concave side of the warped spars and stuck them between some MDF with weight to get them straightened out.

You can never have enough clamps! I need more... grr

RVM

If the spars don't straighten out perfectly, I may replace the basswood spars with spruce. Any opinions on this? I hear it is a better wood for this application anyway.

RVM

I did a good bit of work on one wing panel last night.

I was able to get the three warped basswood spars straightened out. This is a good thing because I really didn't feel like buying anymore wood for the plane. The basswood is also more than strong enough for this application.

The trailing edges still had a lot of flash left on them, so I had to sand that down. You'll also notice in some of the pictures that the trailing edge is actually wider (top to bottom) than the end of the ribs, so to get the sheeting to lay correctly I'll have to sand it down even more.

I glued all the ribs onto the spar, and was about to take a picture when I dropped the camera onto rib #6. It shattered, literally. Probably due to the tension placed on most of the pieces because of their less than perfect fit. Of course, it doesn't help matters that the camera landed directly on top of the rib, either. I wasn't even going to try and piece this part back together. Instead, I took rib #6 from the stack for the other wing panel, pulled out a sheet of 1/16" balsa that wasn't too soft, laid the rib on top for a guide, took my knife and cut a new one. I think the replacement came out rather well. You can definitely tell it's not from the same wood stock as the rest of the ribs (or kit for that matter), but it fits in there almost perfectly and since I'm not using clear covering I really don't care. [8D]

To get the spars set correctly, you have to use a gauge supplied with the kit. It basically allows you to put the top spar on with a certain offset to the bottom spar (top and bottom being relative to the building board) to facilitate proper dihedral. Well, the spar was too long. I had already lined up the outside end of the spar to the end of the plans, so I had to cut off about 1/4" from the inside. I did it without a miter, as there wasn't enough room to use one, so I very carefully eyeballed it and slowly sawed through, keeping the blade at 90 degrees. It worked well and I was able to get the spar set correctly. Then I found a problem with the spar - it was too thick. The second spar was about 1/32" higher than the topmost part of the ribs. I took it off, laid it on my MDF cutting board and went to work with a 22" bar sander and 100 grit sandpaper. A few minutes and a few test fits later the spar rests nicely where it is supposed to be.

RVM

I got the ribs and spars set and glued in. After letting the glue dry a bit (I gave it 15 minutes or so), I double-checked the alignment of everything. Perfect, front and back. No warps, bends or otherwise undesirable discoveries were made. Save one. If you look at the picture of the end of the spar again, notice that the trailing edge is short. Well, you can't see the TE in the picture, but you can see the rib. I had to move rib #15 in 1/8" (the TE was short by about 1/8"). Not a big deal, but it goes to show that Goldberg (or Lanier, since I believe they now own Carl Goldberg) needs to pay closer attention to quality.

Anyway, I went back over all the joints with Titebond II. I didn't use excessive amounts of glue - enough to make a nice fillet is all that was necessary. The last picture is of the wing this afternoon, with all the glue fully dried. So far so good. If I have time I'll try to finish this wing panel up tonight.

By the way, I used medium CA on the wing panel. It's not my preference but it proved to be the easiest and most accurate way to glue the parts. The reason is this: many of the parts were less than a perfect fit. Quite a few had to be forced, and quite a few had to be supported. Very few fit "just right". Aliphatics simply dry too slowly, and there was no way I could see to clamp things together until it cured. So, I took my bottle of CA, stuck a long tip on it to control the flow of the glue, and went to work. I put a small bead on all the joints and held it in place until it set. I put the fillet of Titebond on to fill in any gaps the CA didn't get, and to add a bit more strength to the structure. The Titebond also covers up the CA, which I think looks ugly when it dries.


Also, I called Carl Goldberg today. The service representative on the phone was very friendly. I requested all the wood required to build the tail feathers and their control surfaces be replaced; he had no issue with that. He simply asked that I go through and tell him the dimensions of the sticks I needed and the part numbers for the laser cut stuff and he sent it on its way. Great service and support!

parrthd

oh now this is just great............now i've come up on ANOTHER kit that's looking like it would be fun to build.......oh well lemme get my pen out and add this one to my list of "future projects" LOL

RVM

hah! If I have the wing completed by Sunday I'll bring it to the field with me.

parrthd

sounds like a plane....er i mean plan LOL i might try to bring the skybolt fuselage (depending on room)

hows about planning on getting to the field around 12 or so? by the time everythings set up everyone should be outta church and all that so we shouldn't disturb anyone.

RVM

That should work perfectly. [8D]

parrthd

i had the intention of asking you in the last post..... what have you decided to do on the shear webs? front, back, or cut to go in between the spars?

RVM

As per the plans, which would be on the front of the spars. As was pointed out to me, it's not worth the trouble of putting them between the spars.

RVM

I've been too busy getting married this past week to really update this thread any. Of course, there wasn't much to update with, since I did no building. That is, until tonight! I was able to get a little bit done.

I glued in some balsa supports for the 5 hingepoints. I want the barbs to be fully encased in wood and glue. I'll probably use Elmer's Polyurethane glue (same thing as Gorilla Glue), though I am still considering epoxy.

I also got the first of the landing gear supports glued in. This actually fit rather well.

I sanded the top of the ribs and trailing edge to accept the TE sheeting. Also, I had to true the sheeting as it was considerably warped. It made it a bit smaller than I had intended and therefore the sheeting doesn't quite fit to plans. I'll put the other side of the TE sheeting on at the same point for this wing panel, and I'll probably do the same for the other wing panel as well. There are a few precut sheeting sections that may not fit perfectly because of this, but I'll cut some scrap wood to fit and with some light sanding it should fit flawlessly. I again used MDF and some weight to keep the sheeting held down while drying.

I also got the 3/16" balsa glued in. I don't know what this part is called - truss of some kind I would imagine. Anyway, it doesn't quite fit right. Most of the notches in the ribs are 7/32", while the stick is 3/16". I also had to use tape to keep the stick held into the slots since nothing lined up as precisely as one would expect.



The TE is warped this way and that because a few of the ribs are either too long or too short. I'm going to go ahead and finish sheeting it with this problem, but I think what I will do to even it out is sand it down level. After this, depending on if it will effect my hinging, I will either leave it alone or cap the TE with some balsa. The reason for this is that the TE might be too thin, front to back, to accept the hinge points without some overhang of the hinges, even with the balsa supports I glued in.


I noticed that not all of the ribs are 90 degrees to the spar they were initially glued to. A few are off by a small amount. This may account for some minor fitting issues. I don't believe this to be the case, but I'll give the benefit of the doubt to the manufacturer.

parrthd

glad to see you got back to some building. that wing panel is taking shape. i've not got a lot done on the skybolt but i'll post within the next day or two.

RVM

It's funny that with this kit, the quality of the wood seems to be quite good, but the quality of the laser cutting is mediocre. I remember my die cut kit in the 90s coming together with a great deal more accuracy. I believe if this kit were up to the standards of my BTE then this would be a near perfect build so far.

I think my next plane will be scratch built, if only because I'm a perfectionist.

DVI

I built my Chipmunk about two years ago. I power it with a OS61FX engine. It flys very well, does great snaps and spins.
I have never posted a picture before, But will attempt to do so.[img][/img]