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

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Kmot -> RE: Bernard Dumas' Canadair CL-215 (10/4/2006 4:54:02 PM)

Ciao Giacomo! Any more updates?

-Tom



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (10/6/2006 3:39:02 PM)

Quite busy right now [:@] ...



Kmot -> RE: Bernard Dumas' Canadair CL-215 (10/8/2006 10:34:58 PM)

Understood. I know how it can be sometimes! Ciao.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 5:31:31 PM)

Hi gentlemen!

Christmas time inspired me to get back to the long-abandoned building board for some more dust-time!

Sheeting the hull ahead of the step

A rather uncomplicated matter given the simple shape but... things got though approaching the nose. Rememeber I couldn't bend those very soft 5x5 balsa sticks?

I wanted to run one(*) balsa sheet from the step to the nose but I couldn't. Bending the grain was really too much -close to the nose-. I decided to end the parallel-grain sheeting up to bulkhead C20 and continue with cross-grain from there on.

I added some scrap balsa (red arrows) around the bulkhead where they'd meet (green line) to provide better support and anchoring.

After-thought: a better (and too late) way to sheet it is to end the parallel-grain up to a point where a single cross-grain sheet would be required. Bending is indeed critical but only -really- close to the nose. Hull will be fiberglassed so it isn't really a structural matter... Additional support (scrap balsa) is advised anyway.

Sheeted with Gorilla Glue, applying pressure with the custom-bar sander and masking tape. Remember GG foams... make sure things stay where they belong...

(*) Hull width requires you to join balsa sheets to cover it in one piece. I prefer to do it prior to sheet for a better surface at the joint.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 5:38:26 PM)

The cross-grain sheeting bends easily and follows the composite curvature of the hull up to the nose given the appropriate amount of -help-.

Gorilla Glue really turned out fantastic for this kind of jobs: fills the gaps, sands easily and is both light and strong!



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 5:45:07 PM)

The last 2 sheets were glued at the same time.

Everything was then trimmed masking the thin 1.5mm sheeting itself.

I'm satisfied with the results. Except for the sheeting pattern.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 5:59:29 PM)

Wing holding plates (WHP)

They're 10mm ply and should be placed at the locations shown on the plans.

They look rather beefy so lightnening holes will be drilled once wing attachment is completed.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 7:45:39 PM)


quote:

ORIGINAL: g_boxwood
After-thought: a better (and too late) way to sheet it is to end the parallel-grain up to a point where a single cross-grain sheet would be required.

Just added a pic to clarify a bit what I mean (lower pattern). Or at least this is what I hope... Dotted lines denote joined sheets.

I need advise on splash rails: are they needed? I saw a few model designs feature them.

Do they:
- improve water handling?
- prevent water from hitting the props?
- help get onto the plane quicker?

Thanks,



Strykaas -> RE: Bernard Dumas' Canadair CL-215 (12/19/2006 8:30:14 PM)

Great !

quote:

need advise on splash rails: are they needed? I saw a few model designs feature them.


They are even used on the real ones : "prevent water from hitting the props?"

[image]http://eu.airliners.net/photos/photos/6/1/7/1130716.jpg[/image]

What is Gorilla glue btw ? Any link ?



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (12/20/2006 7:35:01 AM)


quote:

ORIGINAL: Strykaas

Great !

What is Gorilla glue btw ? Any link ?

Thank you, Strykaas.

[GG is a polyurethane glue, you can find more in this thread (page 2, posts #46 and #47)

http://www.rcuniverse.com/forum/m_4400160/mpage_2/key_/tm.htm

and in this useful post that stresses how every kind of gluing job needs a -specialized- adhesive (IOW you can't use GG instead of -every- other adhesive):

http://www.rcuniverse.com/forum/m_3895442/anchors_3895442/mpage_1/key_gorilla%252Cglue%252Cconcerns/anchor/tm.htm#3895442

I suggest reading post #49 directly.]



Strykaas -> RE: Bernard Dumas' Canadair CL-215 (12/20/2006 10:44:43 AM)

Thanks !

Here is the pictures I wanted to post :

[image]http://www.clubhyper.com/reference/images/cl215g3.jpg[/image]

[image]http://www.clubhyper.com/reference/images/cl215g5.jpg[/image]



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/7/2007 2:36:47 PM)

Happy new Year to everyone! I know I'm late but I've been away... from town and ADSL...

Although I was away from my workshop I did my homework and CAD modeled the MAIN GEAR: I basically drew again all the components already drawn by Bernard just to get a better understanding of the involved cynematics. Again, everything is very well thought-out and the gear looks incredibly scale as well (check out previous Strykaas pic)!

I first modeled the gear in Rhinoceros and here are the resulting renderings.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/7/2007 2:42:29 PM)

I then turned to the more engineerically-oriented SolidWorks: it turned out to be THE tool for such kind of jobs and I even got the complete gear to retract via a linear actuator (as it should be).

Nonetheless SW revealed some minor issues here and there, in the form of interference between some of the involved components; it won't be a problem to fix them anyway.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/8/2007 5:40:41 PM)

I got the animation into .AVI format and I posted here on RCU Videos; here are the links:

- front view:

http://www.rcuvideos.com/view_video.php?viewkey=a15a815563df9827f48f

- dimetric view:

http://www.rcuvideos.com/view_video.php?viewkey=8ad8561b150d93000ddf

I also attached pics a few more pics showing the gear in the up position.



Strykaas -> RE: Bernard Dumas' Canadair CL-215 (1/8/2007 9:21:58 PM)

wow good work :) !

One remark though : air tube throw looks very limited which might induce play once fully retracted / extended (e.g. rattling at low rpm). I would make it as big as possible and get that air tube anchor point as far as I can from the rotation axle. See what I mean ? Keeping it scale under these circumstances is not easy.



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/9/2007 6:25:28 PM)

Hi strykaas! Thanks for your comment! I don't know if I did understand it right but I'll provide some additional infos about the setup that may help to clear things up. Here is the complete system:
[image]http://www.geocities.com/g_boxwood/SOLID_07.gif[/image]
As you see each leg has its own cylinder, while the 3rd -floating- cylinder is for the locking mechanism. Locking in the down position occurs when the 2 highest arms align (along the green line): loads from the ground are transferred up to the hinge where they are fought by reaction forces (blue arrows) coming from the anchor point. This is what keeps the gear down, not the air cylinder.

To unlock, the highest cylinder (the floating one), pushes the arms away, the arms rotate and the hinges flex, moving toward the fuse. At the same time the retracting cylinders pull everything up without locking it in the up position.

Sorry for the description but everything will be much more clear now. As I said I probably didn't understand exactly what your concern was so please feel free to get back to it so we can deal with it! That would surely help!



Kmot -> RE: Bernard Dumas' Canadair CL-215 (1/10/2007 4:43:48 AM)

Hi Giacomo!

Wow!! Your work continues to just astound me! And not only the balsa wood work but the CAD and animation. You are quite something! :)

-Tom



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/11/2007 7:08:02 PM)

Thank you Tom!

I uploaded the videos showing the cinematics with all 3 air cylinders: not that much different anyway.

Front view:

http://www.rcuvideos.com/view_video.php?viewkey=3fd865d366d5d9ee810b

Dimetric view:

http://www.rcuvideos.com/view_video.php?viewkey=67653eb51d4eb40acaa8



maddog 71 -> RE: Bernard Dumas' Canadair CL-215 (1/15/2007 3:00:20 AM)

Hello guys don't mean to intrude on your forums. But some one told me about your CL-215's on here .Thought I would come over and take a peek! Any way here is a photo of me and my dads project

MADDOG



maddog 71 -> RE: Bernard Dumas' Canadair CL-215 (1/15/2007 3:16:19 AM)

BY THE WAY HERE IS A COUPLE MORE PICS. Its estimated to be about 55 pds powering with two g-45 gas motors !
MADDOG



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/15/2007 6:41:49 AM)

Welcome on board maddog!

Very nice project! And really big as well!

Did you scratch built it from your own plans? What wingspan?



maddog 71 -> RE: Bernard Dumas' Canadair CL-215 (1/15/2007 5:40:29 PM)

Hello Giacomo
In regards to our CL- 215 its 12' or 144". They were enlarged from Steve Gray plans out of Model Airplane news. Around 50% larger
with some of our own modifications. The fuselage comes apart at the middle just behind the landing gear at the step. For easier transport
and the wings breakdown into three pieces stabilizers also come off! Well gotta go to work I drive a truck so won't be back till next weekend.

[:D] MADDOG



Strykaas -> RE: Bernard Dumas' Canadair CL-215 (1/15/2007 8:18:52 PM)

Giacomo,

That was it. The missing floating cylinder at the top was the answer to my remark. There was no way you could get solid lock in 'retracted' position without this additional cylinder.

Keep up the good work !

By the way, how are you going to build this gear ? Do you have access to any milling machine ?



g_boxwood -> RE: Bernard Dumas' Canadair CL-215 (1/16/2007 8:01:31 AM)

quote:

ORIGINAL: Strykaas

That was it. The missing floating cylinder at the top was the answer to my remark.

Perfect then. Thanks for telling [:)] ... there are a few things that still need to be worked out though. Keep the good advises coming!

quote:

By the way, how are you going to build this gear ? Do you have access to any milling machine ?

No, I'll provide all the info and the CAD drawing to a friend of mine who's a craftsman in this regard: it will take some time 'cause he works and he does alu accessories for me in his spare time (being paid of course). I figure it will take some time but I can't see any other option. I guessestimate I'll give him between 300 and 400 USD for this job. This is probably less than what Robart would ask IF they made the unit.

QUESTION: is there any air cylinder available that is best suited for retracts? Does anyone have any advise: I see Robart makes them but also some other brand like Skymaster...

http://dreamworksrc.com/catalog/index.php?cPath=46&sort=products_sort_order&page=6

I need around 1" stroke, bore isn't a concern but they are all around 3/8" which is fine. Will they be strong enough at 11 pounds @ 100 psi? I'm using 3 of them... or at least every wheel has its own, the unlocking cylinder may be -weaker-.



Kmot -> RE: Bernard Dumas' Canadair CL-215 (1/16/2007 4:49:27 PM)

I was going to ask what the top cylinder does. Then Strykass claimed it helps lock the gear. I still don't understand. How does the top cylinder lock the gear? I can't see any movement in the CAD video. [sm=confused.gif][sm=spinnyeyes.gif]



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