CA Models Osmose Delux ARC

[Jim Woodward]

Hi Guys,

I decided to build a new pattern plane for the remainder of this season and for next after selling my other planes. I decided to go the CA Models Osmose, Delux ARC version purchased through Luiz of Netbox Hobby in Miami, FL. I first saw the plane back in December when I picked up a 38% Extra 330 to build and I was impressed with the quallity of the planes then. Thank you Luiz.

My first impressions of the delux version of this kit is that it is very similar to the quality of the ZN Line and PL Prod kits I had built in the past. The fuselage forward 3rd is CF, then transitions into kevlar. There is also a thin foam lining around the fuselage. The chin cowl is also CF, and I have elected to add the CF canopy section as well in place of the fiberglass frame and clear canopy of the stock kit.

This is ARC minus tank, servo, nose-ring, and engine mounting. A significant ammount of work is done to the plane such as all wing/stab/rudder wood work and alignment, but you are left to installation of the tanks and such. I think this strikes a good point where we can customize the gear installation, and the hard work is basically done. Upon receipt of the kit I checked the alignment of the plane on my 'truth' board, and it was obviously "straight" to my eye, and measuring I'm glad to report!

That said, here we go: I first decided to create light-ply/cf stiffened formers that would strengthen the center area of the fuselage, and double as tank mounts. These were hardly any weight, and yet added incredible strength to the fuselage wing area.
Thanks,
Jim

[Jim Woodward]

I guess I should say that I first made templates for those formers out of 1/16" balsa, then cut the ply pieces. I lapped all joints with a skim of Hysol.

Happy with this, I looked at the adjusters next. The adjusters has some considerable play up and down. I studied this for a minute and decided it was due to the fuselage side flexing in and out when pressure was added to the adjuster. To "stiffen" this area, I created a light-ply CF stripped 1/2 former that ties the wood mount of the wing adjuster to the fuselage side and fuseage floor, then to each other. This single 1/2 former added AWESOME strength to this area!!! At this point the only play in the adjuster is between the clearance of the 4-40 adjuster screw and the adjuster cage. Not sure how to get that out, but I'm satisfied with the improvement. This is easy enough to add that I would suggest you guys check out your planes, and see if you detect fuselage side wall flexing in that area.
Jim

[Jim Woodward]

After this I installed the rudder servo plate. This is a phenolic plate and while lite, you need to examine it a bit. I added a small section of ply on top of the plate, and two lenghts of ply below the plate to stiffen it a bit. After marking its location, I glued in some triangle stock, then glued the plate on top of that stock. The fuselage is now VERY Stiff throughout the radio compartment
Jim

[Jim Woodward]

Because I'm going to run FUT 9650 servos in the stab for the elevators, I want to mount my throttle servo, header tank, and battery forward fo the gear plate. Here are the trays I came up with. I'm using the header tank as "free-ballast" incase I end up a bit tail heavy due to tail mounted servos, not because the motor needs one to run properly. The battery will be A123 1100 mah pack, no regulator.

I am using dual elevator servos for my own reasons. #1, there are no glue joints inbetween the servo and the surface! The mini servos are mounted and use MK hardware, Hangar 9 ti-prolink, and MK bb clevis. On almost every DEPS in the past one of the glue joints is eventually going to break in the system, and I decided to forego that on this plane.

Seeing these pictures reminds me that I had already mounted the landing gear. There was no surprise there, other than to mark your own holes and position the landing gear far enough back as to not interfere with the chin cowl. Still though, some minor clearing of the chin cowl was necessary to clear the gear.
Jim

[Jim Woodward]

On to the firewall. This kit happened to make it out of the factor with a "straight" firewall, instead of being offset for right thrust. No biggy - I knocked out the original firewall and Luiz supplied me with a new CF firewall. I took to installing the firewall and nose ring assemblies.

At this point, I believe the best stock nose-ring to use is sold by www.buddengineering.com Jerry's nose-rings require no modification, and float nicely around the front of the YS. I'm also using Jerry's engine mount again. This is the 4th plane I'm used his mounts on and have had very good luck with the system (Thank You Jerry).

To install the motor, I propped the plane up on its tail and let the spinner/prop/nose-ring/motor/mount assembly rest on the nose of the plane, which sets the angles just right. I pushed up the new firewall and tack-CA'd everything into position, preyed, then took it all apart on the bench. Not having broke any of the tack joints, I then Hysol'ed everything into position. This was the easiest and fasted engine mount I've ever had, and that spinnner ligned up perfectly - very happy with the result.
Jim

[Jim Woodward]

More engine installation pics.

[Jim Woodward]

A quick note about the chin cowl and canopy - after reseting the new firewall I decided to forego the "quick" spring clamp, in favor of using hex-head servo screws threading into wood tab and yellow nyrod. I really don't like to use blind nuts in these areas, in case you have one strip or spin, and all of a sudden you can't remove the canopy or chin cowl! The chin cowl is held on by two pins in the backc, and two screws in the front. I'll have to get a picture of it later.
Jim

[Jim Woodward]

Stabs - like I said, Futaba 9650 servos, MK hardware, Prolinks, and Sullivan control horns will all be mounted in the stabs. Monocote is already done Servo mounts are 1/16" balsa frames with 1/8" light ply rails. I did not recess the servo into the stab further as to less angluar differences between the control horn and the servo horn.
Jim

[zzw26n]

Mr. Woodward! just an awsome job!

[BreadBowl]

Damn you work fast Jim! Looks good, when do you think it will be airworthy? I take it also that you sold your Abbra?

[Jim Woodward]

ZZW26N - All in a days work right ?

Ryan - thanks. I am hoping to have it airborne in 2-3 weeks. I sold the Abbra to my closest friend for a backup for his nats trip this summer. Due to other issues, he was still not able to attend though.

I think the Abbra is a great flying airplane. There may be better, but I was very happy with how it went through P & F09. I like what I see in the Osmose too. The fuselage is mid-wide in the nose, and wide through the wind saddle area and it carries the width for a while into the tail moment. The TE's are pretty thick. Wings should finish out 15-15.5 oz or so. I'll post some pics of them later. I should have one wing finished monocoted tonight. I think CA Models have come a long way in quality. The wood work, rounding of tips and such, looks pro to me.
Thanks,
Jim

- as to working fast - when I'm in the garage wood chips better be fly'n!

[Jim Woodward]

Hobby Shop ALERT! Those control horns on the stab are from Sullivan, two for $4.95. Because the ply hardpoints were already installed, I needed a control horn that surface-mounts so I decided to give these a try.
Jim