A winter project!?

[pierre sarault]

An Andy Lennon Snowy Owl Brian Kizner will remember. It had crashed after I inadvertently reversed ailerons on my radio...(not a good thing). Well, the fuselage, T tail and wings are recoverable...i actually started to repair the wing spars...repair photos later. Here's the original.

It was built very light and the wing spars were obviously not meant to withstand torsional loads,,,so I'm reinforcing!

Perhaps it can be used as a photo platform = it is very stable, can fly slowly and has NACA leading edge "droop" and immense flaps.

It will be converted to a tail-dragger.

Any ideas?

[pierre sarault]

Here are some pics of the original (before its crash)
Photos of the recovered and partially repaired parts to follow.

[briankizner]

I remember well the day we acquired that plane as well as several others. We purchased them about 12 years ago from a master builder who was afflicted with Alzheimer's. The late Andy Lennon was a Montrealer (lived in DDO, I think) who was a great designer of RC aircraft. He was regularly featured in the RC magazines of the 60's and 90's.
As I recall, the Snowy Owl was an excellent flier. The problem with all its advanced features was that the complexity meant a lot of finicky details to adjust and keep track of in order to fly. Good luck with the project.

[pierre sarault]

Thanks to Brian for his comments.

Here are some pics of the beginning of the repairs; it is possible the plane will be reconfigured as a tail-dragger and the servos for the ailerons will be relocated in the wing instead of the intricate levers and torsion rods inside the wing towards a central position for the servos (that's the area where the original structure was weakest). A mini-servo will be located in the fuselage near the rudder to actuate the elevator (a T tail arrangement)...otherwise the pushrod was binding a bit from all the way forward the fuselage (servo tray).

The black stripes in the photos are carbon fiber strips added to strenghten along with multi-ply plywood veneer epoxied in place (wing).

The actuation mechanism for one of the flaps binds a bit so the wing will be openend at a particular location underwing to correct the problem (bellcrank mount / bolt / linkage?).

The designer and the builder forgot to configure access points (hatches) for some of the sophisticated control mechanisms as well as structural robustness of the center section of the wing (should have made it 2 sections)

The "New" Snowy Owl will possibly feature an above-wing Canopy and a cylindrical cowl (as for a radial engine)...

It should look like a slow transport plane...maybe floats or skis should also be considered?

[pierre sarault]

The story continues in Fevruary and March = go to these newer posts

7827

7828

7829

7830

[Sempai-mj]

THe round cowl really changes the look of the plane. cool.

[dhamultun]

Can't wait to see it fly!

[pierre sarault]

Thanks for your comments...
David, indeed it should be interesting to fly!
The following are more pics of the rebuild / mods.

I am also addding strength to the original without much added meight.

Pics show the Wing hold-down / fuselage beam, the servo mounts for Throttle and Rudder , the sub cowl cover, the cockpit panels and bulkhead taking shape (patience they say...and making things fit right).

Planning on an 8 Oz. fuel tank (yes its an internal combustion engine OS 0.40 SX)

Soon, the wing braces and servo mounts...to be continued...

Your comments are welcome!

[pierre sarault]

Continued...
The custom cockpit fits...basswood used with lite ply..the glazing has been cut but will be installed only when the rest is painted and the fwd section covered with monokote or ultracover (black).

The seams for the clear glazing will be covered in trim tape and the cockpit will have a much trimmed printed photo of an instrument panel (its an inexpensive solution).

A balsa cover/fairing over the wing bolt-down is next among other things such as fuel tank cradle, servo installation, wing servo support, fuselage covering, electrical and electronics,...etc.

[Kevin Rochon]

Très bien Pierre mais n'oublie pas le poid est un enemi, il semble y avoir beaucoup de Ply(peut être faire quelques trous?) et le Basswood? n'aurais-tu pas pu utiliser du balsa? Le cockpit n'est pas structurel.

C'est juste des suggestions.

[pierre sarault]

Thanks Kevin for the comments;

the ply is 1/8" thick Lite-Ply (plywood layers with a balsa layers in-between) and as you can see from the basic fuselage (the part that was originally there...the original design used multiple 1/4" thick hard plywood (5+ layers) bulkheads which I have cut down. In the repaired fwd section of the fuselage, I do not use conventional bulkheads and the fuel tank braces/supports and any eventual bulkhead are going to be foam-core with a veneer laminate on one side (very light but strong).

Holes in the lite-ply fuselage sides were planned since the beginning, I just have to find a proper hole cutter about 1/2" to 3/4" max. dia....if I had a laser cutter I would have designed an interesting cutout pattern...but I don`t...

I agree Kevin, the cockpit framing with a base of lite-ply is a bit on the strong side also a bit heavy. I could have used something other than basswood; I did try balsa but I wasn`t satisfied as the framing was warping (actually snapping off one of the fwd struts) as I tried to bend the clear plastic windscreen glazing around the outside frames. Keep in mind the cockpit is also an access hatch held in place by screws through the fuselage sides.
More coming up soon and thanks again...lets see if I can find a sharp hole cutter...any ideas???

[pierre sarault]

Progress report:
Coming along OK...now a spring project (time lacking)..
Engine fuel system, fueler test fitting, 8 oz. tank, servos connected and throws tested, elevator servo installed in aft fuselage (bend is sharp to T-tail/elev.).
Cockpit glazed and white "framing" done...this was demanding as the glazing had to be "made to measure". The modified exhaust system also fits nicely with the bent tips - the original mods had been made to go in my old Me-109F. A photo also shows the fuselage underside with exposed LG fittings (will be faired-over)...torsion bar suspension. Also shown is weight reduction tricks like the pink foam fuselage plug covered with thin balsa (using Shorgum) and ultracote.
Next, before covering fuselage I have to do some pre-balancing by moving battery way up front (engine is small (OS 0.40 SX)), maybe adding PA-2 (pilot assist) up front and dry fitting the wing mounting dowels and front bolt anchor brackets ...then testing the CG...
Then its going to be the wing servo mounts, the servo installation, the flutter reducing panels forward of the ailerons, the wing repairs and covering....and re-balancing the whole to the design CG...

Question: Does anyone have a spare dummy radial engine approx 5" dia. they would be willing to part with or sell?

Looking forward to finishing this project and to call out "test flight" at the field!
Actually this might be a good camera or launch vehicle platform...lets' see how it flies...

Thanks for your input and support.
7950

7951

7952

7953

7954

[pierre sarault]

Well, the last few weeks were wet (rain) and busy for me but I did get around to the most difficult part = reconnecting the wing's control surfaces and the flaps to servos. The original layout and servo tray had been destroyed and was impractical anyway. It was revealed by probing around and looking at the original dwgs. that in-wing servos could NOT be retrofitted, instead the pushod/bellcrank arrangement already in place would need to be used. Also the ailerons are controlled by a single servo actiuating two 30" long torque shafts which send movement to each side and an articulated secondary shaft via 2 control horns...sounds complicated? Well, it is as Brian Kizner stated some time ago! As the servo mounting tray and sub-frame neededreplacement, I used foam-coer lined with veneer both sides and used lite-ply for the servo mounting trays. Had to position one tray for the ailerons at approx 20 degrees to avoid binding of the short arms connecting to the torque shaft control horns! It works! I also added extra carbon fiber strips to reinforce the secondary spar (I don't like the original design = too flimsy). Forward, a small bustle aft of the cockpit helps to fair the junction between wing and cockpit, the ABS angle brackets (test units shown) couple the main wing spar to the mounting spar in the fuselage with nylon bolts. The rear portion of the wing is plugged-in with bamboo spikes in a bulkhead just aft of the fuselage center section...phew!!

Next is covering with 21st Century fabric heat-shrink covering...(yes I still have some like for the original)...that's going to be quite a task!8002

8003

8004

8005

8006

[briankizner]

Sure, Pierre, blame me. Looks like a great project for you and your solution looks less complex. Having the servos connected more directly ought to be less sloppy with fewer possibilities for failure.

[pierre sarault]

Thanks Brian, it is a challenge and I am learning some new tricks...in great part thanks to you.

Cheers,

[pierre sarault]

Well, even though it has taken "forever" it is almost ready!
Would probably be great on floats!

Lots of adjustments made and some yet to be made.
Will eventually swap out the OS .40 SX for my OS .50 Ring type = to help with balance and add power (the "T" tail is heavier than it looks because as Brian Kizner once remarked, this model is complex and the internal controls are also complex and on the heavy side.

Applying the Century 21 fabric is not like applying Monokote...but it worked out fine...yes this plane's got lots of patches...

Next pics when its in the air?

(Been busy with contract with end-of-month deadlines...only little time for hobby)

Hope to be able to go in a few weeks...

p.s.: for those who wanted sun and heat...your order was filled...but i'm not sure it came through HK...

Cheers

8094

8095

8096

8097

[briankizner]

beautiful work as always

[Kevin Rochon]

Looking good Pierre!

There seems to be a lot of building and or fixing this summer:rolleyes:

[pierre sarault]

Thanks Brian, hope it all works out in the air!

[pierre sarault]

Kevin,
I saw some of your posts, but I wasn't sure...yes a lot of building and repairing...also its either too hot or its raining...
Hope to see you soon...I'll probably start off with an old trusty plane , then the repairs, then...

[pierre sarault]

Well, Kevin, Brian and all of you out there...the repaired Andy Lennon Snowy Owl is ready for its test flight!

As you saw in previous posts, it has been modified...twice and now the servos have been adjusted, the Balance Point Set (CG) and she is ready to go...

Had to elongate fwd. fuselage a bit more (2") and switched engines from OS Max 0.40 SFR to OS 0.50 SX (ring). Beefed up the LG also. The dihedral is per original spec. but I find it on the high side, it will probably balloon a bit out of a turn and I added flutter mitigating resistance on the lower aileron surface.

The cockpit actually adds transversal strength to the fuselage and could be modified to house an FPV camera...but I'm not there yet $.

[Kevin Rochon]

Nice Pierre, original design. So when is the maiden?

[briankizner]

nice work. I bet it will be a very gentle flier.

[Sempai-mj]

Cool plane, putting the bigger engine was a good choice!