Avro CF-100 Canuck - Twin 70mm EDF

DamoRC

Elite member
Mentor
I should be working on the C-130 as part of March Madness, but I get easily distracted. Came across one of these on Youtube, had a couple of 70mm EDFs looking for a home, and thought "Why not?" Andre was considering this plane for a twin 64mm build at one point but I don't know if he made any progress.

CF-100s_423_Sqn.jpg

They also had a "podless" version (the pod positions could carry a variety of armaments).

No pods.jpg

So I got to work, originally planning for approx 40 inch wingspan.

1 First Plans in Skectchup.jpg 2 Half plane and profile done.jpg 2a Sketchup Half plan and profile.jpg 3 First 3D ish assembly.jpg 4 fuse disks added and sized.jpg 5 paneled full fuse.jpg 6 paneled fuse with other components.jpg 7 full nacelle.jpg 8 full fuse and nacelle.jpg 9 Fuse and Two Nacelles 55 inch.jpg

At this point, trying to model in a 70mm EDF with an appropriately large exhaust (~85-90% FSA) while having some form of taper at the exhaust, I realized that the plane was going to need to be a bit bigger. By the time I had scaled it up so that the exhaust diameter was fine and the nacelle looked kinda-sorta scale-ish, the plane had grown to a 54 inch wingspan. So it's going to be a bit of a beast. I flattened out the parts and printed them out.

First set of plans.jpg

This is what the current Sketchup model looks like.

Version 1_0.jpg

DamoRC
 

Attachments

  • CF-100 Final Full.zip
    1.5 MB · Views: 0
Last edited:

Zephyr1

Elite member
I'm very excited to see how you put the EDFs through the wing! It's something I've thought about doing before but never figure out. Good luck!
 

DamoRC

Elite member
Mentor
I'm very excited to see how you put the EDFs through the wing! It's something I've thought about doing before but never figure out. Good luck!

I think you may be disappointed :(

The earlier drawings in the first post were based on a simple plan and profile view, making it look like a mid-winged plane. In reality it is a low wing, so I am gonna totally cheat with the EDF units. The wing will be flat-bottomed, and the EDF housings and fuse are flat-bottomed where they meet the wing. So basically, the plan is to attach the EDF units to the fuse so they share a common flat bottom surface and then the combined units will sit directly on the lower surface of the wing. Only the area from the outboard side of the EDF to the wing tip will have an upper wing surface (and perhaps a fillet to fill the gap between the EDF unit and fuse). Then spars on the lower and upper wing surfaces that go through the fuse and EDF unit to hold the whole thing together. Not pretty, nor elegant, but effective (I hope).

DamoRC
 

DamoRC

Elite member
Mentor
Starting the build - progress thus far.

Printed out a tiled version of the plans - all 52 pages! Cut and taped the sheets - this is not going to be a low part-count build.

12 IMG_3246.JPG
13 IMG_3247.JPG

Started with the fuse parts. Each part is cut and scored according to the plans and the scores are widened a little by running a blunt-ish skewer along the cut. Each part also has 2 frames that need to be cut - these are to hold the part shape while the Gorilla glue sets. This is a pic of the fuse parts dry fit into their frames.

14 IMG_3248.JPG

At this point the first problem with the parts is observed - look how narrow the tail piece is at the end. Given that this piece is going to hold the double foamboard layer V and H stabs close to the end, I am going to need a little extra GG in here to make sure the piece is strong and stiff.

This is just an example of how the parts look when they have GG added to the score cuts and are then folded and glued together at the seam with hot glue.

15 IMG_3253.JPG

Having glued and framed the fuse parts, moved onto the nacelles. Here are the nacelles dry fit into their frames with the fuse parts glued up and drying in the background.

16 IMG_3252.JPG

Going to re-use the nacelle frames for the second nacelle, so while the first is drying, moved onto the EDF holder. Order of operations here is important. After marking out the piece, cut the EDF hole first and confirm that the EDF will fit snugly but easily into the hole before finalizing the part. This frame is reasonably fragile, so if you cut it completely and then try to fit the EDF it will warp and possibly split.

17 IMG_3249.JPG 18 IMG_3250.JPG 19 IMG_3251.JPG

Should get the second nacelle setup today and start putting some of the parts together.

DamoRC
 
Last edited:

DamoRC

Elite member
Mentor
A lot more progress today.

This is the EDF mounted in the rear of the nacelle. This is ready for attachment to the rest of the unit but I want to wait until I have a better idea of where the wiring from the ESC will go. The nacelle is mocked up in the second picture.

IMG_3259.JPG IMG_3260.JPG

The tail feathers were cut, twice for two layers of foamboard for the V- and H-stabs. They were laminated using gorilla glue with various weights applied to keep pressure on the layers.

IMG_3258.JPG

The V- and H-stabs interlock with each other and to allow the twin elevator servo wires to pass through the fuse reasonably concealed I added some trenching to the V-stab.

IMG_3262.JPG

Multiple wooden spars were added to the tailfeathers. Although the gorilla glue laminated the pieces just fine, the H-stab had a little flex out near the tips that I wanted to remove and the V-stab has quite a bit of weight to hold up so better safe than sorry.

IMG_3264.JPG

Then the tailfeathers were installed to the rear-most fuse part.

IMG_3265.JPG

The fully assembled fuse is pretty long (Baron added for scale)

IMG_3266.JPG

And this is what is looks like with the two not-quite-finished nacelles.

IMG_3267.JPG

DamoRC
 
That's looking grand :) How do you find working with Gorilla glue versus hot glue? Do you prefer it because it gives you more working time? Is there any weight advantage?
 

DamoRC

Elite member
Mentor
That's looking grand :) How do you find working with Gorilla glue versus hot glue? Do you prefer it because it gives you more working time? Is there any weight advantage?

Thanks!

I use the GG mostly on these tube type constructions, in the score cuts, because it allows time to get all of the lines done and get the tube mounted up in frames to make sure the shape holds. One dry, its stiffer than hot glue and easier to work (sanding etc). This was the first time I have used it for laminating two layers of foamboard for the V- and H-stab. If its fresh, its easy to work with. For everything else I use hot glue.

DamoRC
 

FoamyDM

Building Fool-Flying Noob
Wow DamoRC. That looks so good.

So how do you figure out the CG on this untested plane. from the original plane plan, build a glider, balance it at the 1/3 wing chord and chuck? I saw this because my Bloody Black Widow flew. But a little elevator got it crazy. based on the projects I see out of you, you must have tackled this somehow. What do you think?

-FoamyDM
 

DamoRC

Elite member
Mentor
Wow DamoRC. That looks so good.

So how do you figure out the CG on this untested plane. from the original plane plan, build a glider, balance it at the 1/3 wing chord and chuck? I saw this because my Bloody Black Widow flew. But a little elevator got it crazy. based on the projects I see out of you, you must have tackled this somehow. What do you think?

-FoamyDM

Thanks FoamyDM!

I typically use one of the online CG calculators to get a guestimate and then go pretty conservative on the maiden, maybe 10 to 15 degrees nose down when balanced on the guestimate. This seems to work for me. I never do the chuck glider thing (I probably should).

Thinking of the CG after finishing the fuse last night, I may have to reconfigure the nacelles. The EDFs are going to be behind the CG, and coupled with a heavy tail, I might have problems getting her to balance even with the 2 x 2200 4S batteries that I plan on using. I would like to avoid having to add dead weight as she is already heading for around the 4.5 -5.0 pound mark AUW. I could move the EDFs to the next section forward in the nacelle, but then I’ll be losing thrust. So I am going to wait until the wing is built before gluing up the nacelles completely and see if I can get her balanced.

DamoRC
 

DamoRC

Elite member
Mentor
Getting closer...

Added a nose cap, canopy (which doubles as the hatch), wired the EDFs, mounted the nacelles to the fuse, and got half a wing finished.

IMG_3268.JPG IMG_3271.JPG IMG_3273.JPG IMG_3276.JPG IMG_3277.JPG IMG_3279.JPG IMG_3280.JPG

DamoRC
 

DamoRC

Elite member
Mentor
Thanks guys!

Almost done, finished the wing which includes a CF tube spar, cut reliefs into the fuse and nacelles, and mounted the two together.

IMG_3282.JPG IMG_3288.JPG IMG_3289.JPG IMG_3290.JPG

AUW now looks like it will be somewhere in the 4-4.5 pound mark.

Waiting on HK for a pair of matched ESCs (I think they are way behind processing orders because of the warehouse sale) and the weather has been pretty wet so no real chance to finish or fly for a couple of weeks I think. Planning on doing a metal type finish like the Okha with some red and black like these (although I am not going to add the wing tip pods).

IMG_3283.PNG
No pods.jpg

DamoRC
 

Ketchup

4s mini mustang
Nice job. I obviously can’t fly either because of rain but I might work on my mustang. I will wait to see this at the field when it doesn’t rain though!
 

DamoRC

Elite member
Mentor
Thanks Ketchup!

Weather held up for most of the day so managed to get some painting done.

One thing about the metallic paint, it reveals all of the flaws in the build because the foamboard comes up a little dull but remnants of hot and gorilla glue turn up bright and shiny!

All it needs is a few RCAF roundels and maybe some detail on the nacelle.

IMG_3291.JPG IMG_3293.JPG IMG_3294.JPG
IMG_3295.JPG

After spending all of this time designing, building, and painting, only today did it dawn on me that I hadn't checked whether the thing would fit in the car.

Thankfully, after a complicated process, I was able to get it to fit. At one point I thought I was in a chapter from Dirk Gently's Hollistic Detective Agency, having gotten the plane to fit, I could not get it out again. But it's all good now.

IMG_3299.JPG

DamoRC
 

Grifflyer

WWII fanatic
If the plane didn't fit...

but anyways it looks GREAT! Quick question what are you're specs? I remember reading something about 40 inch wingspan but it looks much bigger than that.
 

DamoRC

Elite member
Mentor
If the plane didn't fit...

but anyways it looks GREAT! Quick question what are you're specs? I remember reading something about 40 inch wingspan but it looks much bigger than that.

Original drawings were for a 40 inch wingspan. Then I noticed that the exhausts of the nacelles were tiny compared to what I would need for a 70mm EDF. So I compromised between a larger wingspan, which is now 54 inches, and not quite scale exhaust (it’s good for the 70mm EDF, but still not as narrow as the scale drawing).

This might make a nice 40 inch wingspan for 50 mm EDFs. If anyone has a pair of 50mm EDFs looking for a home I can scale down the model and post plans.

DamoRC
 

Grifflyer

WWII fanatic
Original drawings were for a 40 inch wingspan. Then I noticed that the exhausts of the nacelles were tiny compared to what I would need for a 70mm EDF. So I compromised between a larger wingspan, which is now 54 inches, and not quite scale exhaust (it’s good for the 70mm EDF, but still not as narrow as the scale drawing).

This might make a nice 40 inch wingspan for 50 mm EDFs. If anyone has a pair of 50mm EDFs looking for a home I can scale down the model and post plans.

DamoRC
Wow that's pretty big, and too bad I only have one 50mm edf:(