Jim Clausen

ZOR,

I do not disagree with you but the height of the elevator is dictated by the plans so therefore I had five axes to deal with. All of the other items you have defined are within spec as it sits right now.
I also checked and double checked each measurement before I locked into place.
Jim

doxilia

My Feedback: (3)

Good job Jim!

I can relate to the difficulty in aligning and installing the stab - just did it myself this past week. It took me three days in all to reach satisfaction. The first day I spent just measuring things about 25 times to "discover" where discrepancies come from. The second I adjusted according to my findings and tack glued with CA (my joint was glass/wood so the tack gluing is a little more forgiving). I aligned the "anhedral drop" using the floor as a reference as I don't have a table large enough to permit measurement of an assembled 60 size classic. The only problem is that floors in old houses like mine can be 1/8" off when they report being flat... At that point, I came back the third day and once elevated and sighted from a good 15 feet away, things become more evident. I was able to "crack" the tack gluing on one side and correct - I was about 3/32" too low on the left. My joint is now symmetric, level and square to the fuse.

I'd venture that installing an anhedral stab in a classic such as the Tipo is perhaps the most complex and hardest part of the build. I feel like I've overcome a major obstacle, now it's on to getting the rudder hinged, sanded to shape and the fin tip glued in place and glassed.

You're getting close to priming!

David.

doxilia

My Feedback: (3)

The nice thing about building a wood Tipo is that the datum line or tuck line happens to be the stab incidence line as well. This makes incidence adjustment and/or measurement less of a task than it may be otherwise. In some classics, the stab is located so their chord lines sit precisely on the "fuse top" with a fairing to encompass the space between the vertical and the stab top airfoil (e.g., the Blue Angel).

On the glass Tipo, the tuck line is harder to establish because curvature is molded into the fuse. When building a wood version, the tuck line can be inscribed on the fuse sides and then the curvature is produced about it. Since the fuse sides are flat about 9" from the stab LE, the tuck line can be preserved and used as an incidence reference when installing the stab.

David.

Zor

Hi Jim,

No doubt you have things well under control and doing a fine job.

As I wrote in my previous post "Not all six are always needed".

My post was more aimed at the writing that there was only three axis in geometry.
That is true and covered by my 1 to 3 but I wanted to consider that the orientation is also very important which I covered in 4 to 6.

I wrote before somewhere that I never glue the feathers.
I like to be able to adjust the decalage from stab to wings by shimming and be able to easily remove the feathers in the event of needed repairs.

I aim at having a model that is a free flight while being able to radio control it.
That was our aim when we started making our radios to conrol free flight models.

Ah! ___"The Good Old Times".

Zor

Jim Clausen

Vasek,
You may think that there are only three but if you check into CNC machining centers you will find 5 and 6 axes machines and in robots you might have as many as 8.
Zor defined six for the location of a horizontal stabalizer in post # 150 and he is correct in my mind.
Jim

hrrcflyer

Hey David,
Just think of it as practice for a certain "Illusion".............LOL

Jim,
You are doing as awesome job on you Tipo. Keep up the great work.................

BTW, Sorry for hijacking your thread.

David

vasek

My Feedback: (4)

Jim, I'm not familiar with robots, but in a placing of a stab I can only think of 3 axis; pitch, roll and yaw

any rotation of the stab can be defined by these 3 axes. The "elevation" or height and the forward position of the stab is not determined by "new" axes but rather a system of coordinates in the basic 3 axis reference environment (X,Y,Z)

One can always evoke the axis of symmetry, but the stab has it's own axis (or axes) of symmetry regardless of it's position in space.
The alining of the two (stab & fuse) requires rotation(s) about the 3 axes (X,Y,Z) plus some linear movement (up-down; back-forward) which is determined by coordinates in the basic 3 axes (X,Y,Z) environment...

Cheers,
Vasek

vasek

My Feedback: (4)

oh, and forgot to say that I do understand the frustration of placing a stab in the correct location, and it may seem like there are 9 axes to work with! Been there, done that [X(]

Zor

vasek,

Glad to see you now got things correctly.

I do not know if you ever disigned a model but I cannot think of the other 3 axes (plural of axis) from 6 to 9 you say "and it may seem like there are 9 axes to work with! ".

When designing even the simplest models we have to consider all these variables.

Any explanation forthcoming ?

Regards de Zor

doxilia

My Feedback: (3)

I think we all get the picture on what's entailed in getting an anhedral (in particular) stab installed in a classic - 3 axes (since space is 3 dimensional... at least in low gravitational fields... ), 3 positional parameters on each axis: fore/aft, left/right, up/down. It almost sounds like quark theory but so be it...

I suggest we return the thread to Jim who will soon show us a fully assembled Tipo!

David.

Jim Clausen

Today I was able to get the front retract door made and put in place. It is held in place with eight #2 pan head allen screws. The hard part for me was to get the opening for the gear cut in. I will clean up the opening for the gear tomorrow, take some pictures and post them. Do I need to close up the inside of the front wheel well so that air cannot get into the inside of the fuselage????

I also got the gap between the trailing edge of the wing and the rear lower fuselage filled and fared in.

I still need to cut slots in the fuselage to accomodate the pull pull rudder and elevator rods. Maybe I will tackle that tomorrow.

I also figured out the application of the HobyCo wood filler. I just did not have it thin enough to be able to brush it on. So once I get the front of the fuselage sanded down to the final shape I will start the process of applying this wood filler. Then comes more sanding. After that sanding comes the primer coat for the paint.

Jim

Jim Clausen

I was trying to get the pull pull rudder system and the elevator push pull connections in place today. I was taken aback when I put the elevator in place and saw that the rudder movement was restricted. I have taken a picture for viewing. There is no doubt that the elevators will need modifing. I will try to complete these connections tomorrow.
Not a lot more was accomplished today.
Jim

Jim Clausen

I now have the pull pull setup for the rudder complete. I crossed the cables to get a better angle to the rudder clevis cletes. I did not have any 2-56 clevises that I wanted to use so they are on order. Because I did not have the clevis I have not completed the manufacturing of the pull pull cables. I want to make sure of the length before completing that task.

I started the task of putting on the hobby co wood filler on the lower part of the wing and one side of the fuselage. It is taking multiple coats which just takes time. I plan to sand out the bottom part of the wing then prime it before starting on the upper side. I am doing this because of how soft the wood filler is and thought it would protect the surfaces better if primed.

The elevator modification is almost complete, I just need to put a thin piece of ply on the area that I removed and sand it flush with the other surfaces.

Tomorrow is another very hot day here in Georgia.
Jim

doxilia

My Feedback: (3)

Hi Jim,

got your email and thought I would reply here. The closing off of the nose gear retract bay is not mandatory - some people like to do it others don't. If you don't need access to the nose gear from the inside, you can close it off and do any maintenance from the bottom. Some like to make a rectangular cutout for the NG which makes maintenance easier others prefer the tailored cut look with either a hatch or simply insertion or removal from the wing LE bulkhead.

Using Hobbico wood filler is a nice way to fill the glass grain but you don't really want to be priming directly onto this stuff - the substrate in my opinion would be better if it is "filled glass". You want it to be hard - if you paint on to a certain "thickness" of the soft wood filler, it will crack and cave in eventually. The filling does take some brushing, drying and then sanding until the grain of the glass looks uniform. I wouldn't recommend filling and priming the wing in stages - fill it all first and then when its smooth, filled and hard, prime it. You're basically priming filled glass which should be hard.

BTW, the same goes for the primer. Prime it thicker after a couple of "mist" coats so the primer aids in producing a smooth, and mostly, uniform surface. You will want to fill the primed surface with automotive type filler (e.g., Bondo) in the low spots prior to sanding it out. You pretty much want to sand away all of the high build primer and filler at first in the aim of producing as smooth and uniform a surface as possible. Once you are satisfied you can then proceed to a final uniform primed surface allowing the paint to adhere. All of this also depends largely on what type of paint you are using but, in general, that's the typical approach.

If you can, take more pictures, it's easier to follow and enjoy your thread with them!

David.

Jim Clausen

Attached are pictures of the lower part of the wing. I have sanded it down as can be seen. My next step was to prime but after reading Doxilla's statement I am not too sure about that.
Should I coat those surfaces with either epoxy or polyester resin???
On hold awaiting some comments.
Jim

doxilia

My Feedback: (3)

Jim,

as long as you have a filled glassed surface, you should be in shape to prime. I was just commenting on the fact that you don't want to be priming on a substrate of filler on top of your glass work. If it seems too soft to you, you can always brush on a thin layer of resin (polyester, polycrylic, epoxy or whatever else it is you used to glass your wing) and then sand that down. Just keep it light, otherwise the model will wind up weighing in excess of 9 lbs.

David.

Jim Clausen

I have been creating the fillet radii on the tail feathers and sanding and sanding the wings and fuselage. It seems like I have a long way to go on the sanding of the fillet radii on the tail feathers. I will post some pictures when I get completed.
I did pick up some primer yesterday but I still think that that is at least a week away.
Jim

doxilia

My Feedback: (3)

Jim,

while you are working on fillets, I found that making a fillet on either side of the wing chin block makes for a nice fairing into the wing. In order to facilitate the finishing of the wells, I also brushed on a couple of coats of finishing resin. Being balsa, you'll also want to fill those and sand them down. I used 1/64" ply to line them which makes for a slightly easier finish since it doesn't have to be filled.

A couple of other thoughts:

The ventral fin and bottom of the fuse in the glass version (which was made from a wood plug) is considerably rounder than the picture below. The bottom of the rudder is also sanded to that contour so it seems one continuous line. I think your model will look nicer and will take primer and paint better with more pronounced compound curves. You are still in time to sand the bottom round - you'll have to sand through the glass work but the small area shouldn't take too long to re-glass and fill.

I see that you used the cool Robart hinges. You'll want the centerline of the control surface (base of the V-form) to touch the model at the hinge line. A larger groove into the control to accept the hinge point until the hinge line is snug takes care of things. Air passing through those hinge lines won't be a good thing.

Last little detail that you might want to do is to add some 1/16" sheet around the servo wells down to the hardwood blocks on which the servos mount. Pretty straight forward and makes for a nice finish. Your wells are likely wider than the servos so the smooth wood will look nice compared to the beady foam.

Man,... that guy David, what a pain in the... Gets me to do all that unnecessary work!

I'm looking forward to seeing the primer! I was hoping to prime my wing center section today but humidity is up there - tropical thunderstorms all day yesterday. It's like being in the Caribbean up here in the summer these days!

David.

Jim Clausen

First comment is that I do not feel tht that guy David is a pain. I also agree with the recommended changes, some of which I was going to do anyway.
Currently I am fighting another gout bout in my feet so I am almost immobile.

David, Please email me on your daughters status.
Jim

Jim Clausen

I have been able to do a little this week.
The radii at the lower part of the wing chin block has been added and almost sanded to final form. The servo pockets have been lined with balsa and sanded flush with the airfoil.
The radii at the tail feathers is rough sanded in and some places need more material. I have added some pictures to show where I am in the process.
I plan to work on the tail feathers more tomorrow if time allows. Have some things I must do in the morning and do not know how much time this will take.
Jim

Jim Clausen

I have spent the last two days trying to get the transition between the vertical fin and the fuselage to look decent. I cannot seem to get all of the contours to blend and look smooth like I think that they should. I will keep trying filling and sanding. I will post results if I ever get any.
Jim

doxilia

My Feedback: (3)

He, he... fun isn't it!?

Jim, I'm not sure how you're going about it but masking tape is your friend. The fillets in the pictures above look plenty meaty which is good. I would mask surrounding areas that don't have filler to avoid gouging the wood, then sand them down a fair bit until most of the filler is gone except for a 1/8 - 3/16" radius. It can be rough since you'll build it up to ~ 1/4" to 3/8" radius next.

Once the wood is clear and smooth, remove your masking tape and reapply one strip carefully on the top and one on the bottom curving them around the LE to meet at ~1/4" in front of the stab root LE. Likewise, the masking will be separated from the stab at the fuse 1/4". Don't worry about the TE as you don't want much of a fillet there to speak of - just something minor. When you prime the fuse, it will fill in nicely at that spot.

Once your prep work is done, you can then proceed to produce the final fillet. It looks like you might be using bondo type material. Try using epoxy and microballoons (the white kind) mixed to a creamy slurry - it takes quite a bit of MB. You will be able to get a better contour with no need for sanding by using this stuff. You lay it down between the masking tape (by the way you also need to mask the stab of course same distance as the fuse) with a mixing stick and then dip your finger in alcohol to smooth it down into a nice contour. Some of the mix might come off on your finger - just wipe it off with a paper towel. Keep your finger clean and wet with alcohol. The mix will absorb some of the alcohol and if your finger gets dry, you'll start to "smear" the mix so keep it wet and keep it running. One single pass across from LE to TE.

I like to do both sides on the bottom or top first as it is easier not to have to flip the fuse and you can make them symmetric by eyeballing them. I use 30 min epoxy. When you're done with the smoothing, you'll probably be ready to remove the masking tape as it takes about 15 minutes to get the contour right. If you don't lift the masking tape when the mix begins to set, you'll end up with a mess but you don't want to do it while the fillets are still wet - let the alcohol evaporate and the mix set a bit. Peel off the masking over itself to avoid lifting the mix. It will leave a nice uniform line and fillet. Also, if you lift at the right time, the mix will "settle" down leaving no ridge at the mix/wood junction.

Once that is all done and the mix is hard (wait a day), remask surrounding areas, take a small piece of 400 grit and sand lightly to remove any "speckles" off the surface. This will provide a good base for primer.

I'm not sure when you painted last but when your model is ready for finishing, make sure that the glass work is nicely filled and sanded to 400 grit. I have been using a sandable base primer to show me the imperfections, followed by bondo and then wet sanded down to 600 grit. Once the dents and pinholes (I have many more of these than you will since my fuse is glass) are taken care of, I am using a high build automotive polyester primer - great stuff. A tad expensive but worth it. 80% of the work is in the prep as always. The actual paint is kind of a "treat" after masking, prepping and sanding for hours... But then, you probably know all this.

David.

Jim Clausen

David,
All of these fillets are a buildup of microbaloons (brown in color ) and 30 minute epoxy. I have no bondo involved. I am goin about this very slowly. The area that is giving me fits is where the vertical fin joins the fuselage and those contours. I'll get there, I just do not know when.

I picked up a Don Lowe original Phoenix 8 this week. It was posted on RCU. I now have it in my hobby room and will work on it as a distraction from the radii issues.
Jim

doxilia

My Feedback: (3)

Jim,

cool. I wasn't sure what you were using but I know that brown MB and sanded Bondo have a very similar appearance. The brown MB supposedly sand much better than the white ones - different stuff (phenolic vs ?).

I'm surprised you're having problems in that area since the design basically contours the fin right into the fuse since it is an extension of it. Is it in the area where the LE blocks meet fuse top sheet? A little spackling filler should take care of that area since it is just a slight fill if any. The stab/fuse fillets will pose a different story I believe when you advance on the primer/filler/sanding/primer/filler... where was I...?

In a nutshell, I'd recommend you get them as close to perfect before you even touch the fuse with primer - particularly the ones on the bottom. It's been a while since I've done this kind of stuff and it proved to be a pain in the as.. In any case, you will in all likelihood need some body filler when you are priming. There is some green stuff whose name I forget which is supposed to be much better than Bondo. I've been using the latter and it is ok but you really have to watch the thickness of it - it cracks on sight. I was quite happy with my stab fillets prior to attacking the primer but sure enough, I've gone through 5 layers of primer/filler/sander before applying the final coat before paint. It didn't help that I rested the chin on a wet cloth (forgot to swap it after wet sanding... ) before the primer had fully flashed. I've been pretty lazy and didn't build myself a fuse FW holder in order to be able to suspend the fuse. That will change prior to paint which doesn't forgive.

I probably mentioned it above but I've been using a very cool automotive Dupli-Color polyester resin based primer. It flows on like butter and wet sands like a dream - leaves behind a light paste residue which can easily wash off. Then again, if you have a compressor you have the luxury of all kinds of paint.

Below are some shots of where I'm at with the fuse - for inspiration. Tomorrow I will sand lightly to 400 grit (and remove the little fly caught in my primer... [:@]) and then it will epoxy white time! The wing center section is done - rest will be MK. Killed a little grass in my back yard. [:-]

Wish me luck!

David.

doxilia

My Feedback: (3)

Thought you might also like to see where I started with the wing center section. Although it felt smooth and continuous to the touch, it required plenty of prep work prior to the final coat of primer. It now looks like a single continuous smooth area so I'm a happy camper. White is done. Flash for 48 hrs. I'll post some pics once I've got the red on the underside.

Last pic is LK Missile Red test - no where close to MK. It's more orange than red. Will have to substitute for better match.

David.