RE: Bernard Dumas' Canadair CL-215 (Full Version)

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g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (6/27/2006 3:52:25 PM)

The work so far: all the formers in place, keel and last (lower) 5x10mm stringers to go...



Kmot -> RE: Bernard Dumas' Canadair CL-215 (6/27/2006 5:44:23 PM)

g-box: You are an impeccable builder! This is a fascinating build thread to watch.

Did you move to Italy from England or America? Your command of the English language is also impeccable.

Cheers!



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (6/27/2006 5:52:47 PM)

Thanks a lot! Much appreciated kudos! And glad you like it of course.

I'm 100% Italian... but not -that- proud of my soccer team [X(] [8|] [:D] right now!



bernard.dumas -> RE: Bernard Dumas' Canadair CL-215 (7/4/2006 6:59:07 AM)

The choise of the 2 x 70 Surpass seems excellent, the 90 might be to heavy and not really necessary.

I still have the moulds to make the cowlings and nacelles but unfortunately I cannot manufacture these items for you.
I am currently working on two other time consumming projects : a big Corsair F4U-7 of 2.50 m wingspan and I am also restoring an old car.

But if I you come in France I can borrow you the moulds (to heavy to be sent by mail,DHL , UPS or similar) if interrested contact me by mail.

CU

Bernard



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/8/2006 1:45:05 PM)

I had to pause a little for other reasons...

Back to the tail: I cut the keel out of 3mm lite-ply; I cut it a little bit longer and higher.

Prior to CA it in place I had to make sure all the slots were aligned. That meant widening some of them: when it happens I prefer to make the joint tight by forcing some balsa into the slot to achieve a snug fit again.

I also decided that the slot in bulkhead C31 had to be deepened to accept the keel.

After you're satisfied with the fit, simply CA the keel in place checking everything is square once more.




g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/8/2006 1:50:06 PM)

First pic shows keel notch in C31.

Next are the remaining 2 10x5mm stringers (basswood): again check all the slots align and since the fuselage tapers, file all the slots to the appropriate angle. If the fit is poor here and there, gap with scrap balsa.

CA the stringers in place.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/8/2006 1:51:45 PM)

Note the stringers aft end.



Kmot -> RE: Bernard Dumas' Canadair CL-215 (7/8/2006 5:41:31 PM)

That is a very narrow taper on those stringers at the aft end. Are you going to reinforce them inside?



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/9/2006 9:33:21 AM)


quote:

ORIGINAL: Kmot

That is a very narrow taper on those stringers at the aft end. Are you going to reinforce them inside?

You're right, I will.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/10/2006 6:47:02 PM)

Yesterday I finished the hull. I will sheet it before proceding to the next steps since the fuse is upside down over the plans and the sheeting itself will keep everything aligned.

I nice day of trimming here and there.

I started with the MAIN GEAR BOX sides: simply cut them following the -slope- of the hull.

Sand all the formers flush with the keel or viceversa. You need to sand down the lowest stringers as well.

Former C34 carries some designing mishaps: I noticed it earlier in the process but left it in place; it is very easy to correct.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/10/2006 6:52:27 PM)

When dealing with the taper on the lowest stringers you'll loose every reference past former C42: help yourself with a ruler and draw a line that will guide you through the rest of the sanding.

Here is the rudder post after the internal balsa reinforcements (as Kmot suggested) and sanding.

I wanted to better support the sheeting around MGB and installed those balsa -ribs-. May proove helpful.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/10/2006 6:58:11 PM)

Last are -formers- C43, C44 and C45: use 3/8" wide stick (always 1/8" or 3mm thick), cut longer, place, trace notches, cut and CA in place, sand flush with hull.

That's it! Sheeting next. I'm pretty curious since I'll use Gorilla Glue for the first time. Let's see how it performs. I'd better get used to it a little prior to...



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/13/2006 8:09:22 AM)

Do you think I'll need a water rudder?

Where should it be placed? At the very aft end to increase arm as much as possibile? Is it OK if it won't be right on the centerline of the hull but a little right or left? I don't want to cut through the keel... but I can place it right next to it, let's say 1/8" away from the centerline.



Kmot -> RE: Bernard Dumas' Canadair CL-215 (7/13/2006 4:40:15 PM)

Giacomo, how do you like the Perma Grit tools? Do you recommend them?



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/13/2006 6:04:53 PM)

Absolutely! They're not cheap but they last forever! I got mine like 5 years ago and I haven't replaced them yet.

I have the 14 cm sanding block you saw in the pic but I'd suggest the longer ones as well... I think I'll get the 28cm (11") or even the 56cm (22") soon.

I also got some of the round files available, but I didn't use them as much as the block.

One thing I still have to investigate is what's the best solvent to remove clogged residues. Never tried that but may need to in the next ten years [:D][:D] ...

HTH,



Kmot -> RE: Bernard Dumas' Canadair CL-215 (7/13/2006 11:16:11 PM)

lol, thanks! :D

I am going to get some of these. I have hesitated because of the cost. But yours have been going for 5 years already is good enough for me! ;)



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/18/2006 6:39:50 PM)

Ok: I need to plan where to install the water rudder.

Any advice would be much appraciated.

Attached is a pic with the side view of the bird.

Thank you,



John Hawkins -> RE: Bernard Dumas' Canadair CL-215 (7/18/2006 9:26:34 PM)


quote:

ORIGINAL: g_boxwood

Do you think I'll need a water rudder?

Where should it be placed? At the very aft end to increase arm as much as possibile? Is it OK if it won't be right on the centerline of the hull but a little right or left? I don't want to cut through the keel... but I can place it right next to it, let's say 1/8" away from the centerline.


I would definitely use a water rudder unless you plan on using differential throttle. Before my current project I built an 89" Grumman Albatross and had the same concern as you about cutting the keel so put it off to one side. That works fine but on the 124" Emily just completed I put it through the keel. I meant to scab pieces on the sides but things got covered in before I realized I had forgotten. The fuse is planked without stringers and takes its strength from that so I figure it is plenty strong as is. I believe the 215 uses thin sheeting so perhaps that is a different situation. None the less scabs on either side of the keel should make up for passing the rudder shaft through it.

The Emily rudder is behind the second step and that has worked well so far (8 flights) even in 20~30k wind. With the Emily a rear mounted rudder would be out of the water unless the shaft was very long as can be seen in this screen capture:

I don't know how the 215 sits in the water. Although there are several models of it locally I didn't notice how they were set up. Seems to me that at least one used a long extension shaft down from the air rudder which doesn't look good to me. I would place the rudder forward to keep it in the water when taxing. A larger size would compensate for the lesser moment.

Here's a reference to the question in the Emily thread.
Emily thread



John Hawkins -> RE: Bernard Dumas' Canadair CL-215 (7/18/2006 9:34:47 PM)

I found a picture of one of the 215's flying here. I outlined the rudder to make it stand out.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/19/2006 9:13:40 AM)

Thanks very much for all the inputs John! I'll take care of them as I plan water-rudder installation.

I don't like long shafts as well. From what I saw the 215 waterline is very high (she sits in the water deep)... but I may place the rudder some inches back from the step just to avoid turbolence. I'll let you know.

Thanx again,



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/21/2006 7:19:46 PM)

I decided to practice a bit with Gorilla Glue prior to use it for the first time on a model.

I wanted to test:

1. how much does it expands once cured
2. what happens if you over-apply
3. how well does it fill imperfections
4. how sandable it is

I made 2 quick 'structures' to be sheeted with balsa. One is perfect while the other features some artificial defects and it will be used to test 2. and 3.

Instructions say to

1) dampen one of the surfaces to be glued with a wet towel: humidity seems to activate the glue;
2) apply only a thin layer of glue; it is very easy to do with the applicator tip: simply hold the bottle upside down gainst the surface, squeeze a bit and slide the tip while the glue is coming out... easier done than said, really!

The thin layer was spread on the perfect structure only.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/21/2006 7:27:07 PM)

3) Clamp or weight down for 3-4 hours; it is indeed necessary otherwise the foaming glue will move the joining surfaces around!
4) squeeze all the air out of the bottle to increase shelf-life ;-) ...

Results:

- over-application leads to picture one: imperfections were filled anyway;
- a thin layer produces little or no -oozing- at all;
- adhesion is incredibly strong; GG penetrates balsa very well (check the darker section of the stringers close to the sheeting, fourth picture) and sands incredibly easily!

Way to go for every sheeting job! Longer to set and requires weighting down but well worth it IMHO !



John Hawkins -> RE: Bernard Dumas' Canadair CL-215 (7/21/2006 9:06:04 PM)

Looks like that is working out great for you. I used it for sheeting my last foam core wings and was very happy with it. It seems to expand and lock into the foam very well. With expoxy if you use too little there is the risk of delamination. If you use too much it weighs a ton. The expansion qualities are great for locking things into foam particulary if the fit is a little loose. I use a spray bottle in that case and get the foam fairly damp. I think that makes it expand more.



Kmot -> RE: Bernard Dumas' Canadair CL-215 (7/22/2006 4:25:14 PM)

Very informative report on the Gorilla Glue. Thank you! :)



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (7/23/2006 8:43:12 AM)

Thanks! And John is right about sheeting foam cores with GG: it is the ideal adhesive for that!

Now, back 100% to the tail and to the project for the next week prior to summer holidays.

I didn't know if it was necessary but in the end I added cross-sectional elements to the last three stick formers I made; those formers aren't shown on the plans so you'll have to fit and cut them -on spot- . Once in place it is very easy to sand them to shape using the keel and the lower stringers as a guide.

Said that, it was time to finally sand the hull. To achieve the most uniform material removal it is necessary to use the longest sanding block available! Otherwise you'll end up with a saw-tooth keel and hull...

Gorilla Glue was used to sheet the hull with 1.5mm balsa. You must be sure to apply enough pressure all around the surface to be joined regardless of their position: it may be tricky so plan in advance. I must practice a lot with it [8|] ...



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