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Sep 16, 2019, 02:39 PM
RC 4 Life
sparks's Avatar
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The nacelles are all the same formed parts.
Fitting them are done by trimming and test fitting.
The good news is the inboard nacelles are larger than the outboard. This means you should fit the inboard ones first. If you screw up you can use it outboard.

Skip ahead to fitting the bottom nacelles because the photos are better.
When you get it very close lay sandpaper on the wing, put the nacelle in place and pull the sandpaper out for a close to perfect fit.

Gorilla glue is applied to the edge of the plastic and the nacelle is put in place.
A weight is applied while the glue foams up. The Q-tip is used to wipe away any glue that makes it out from under the plastic.
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Sep 16, 2019, 02:41 PM
RC 4 Life
sparks's Avatar
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You are sort of on your own when it comes to retracts for this model.
They seem to come and go every two months and recommending a bolt on set would be disappointing at best.
The units I chose were modified to take dual main gear tires and was intended for A panther I believe.

You are looking for a set that can be used on a 7 pound model with 90 degree rotation and a long enough strut length.
There is plenty of room in the nose to hide the gear but the mains were very tight as you will see soon.
Sep 26, 2019, 03:25 PM
RC 4 Life
sparks's Avatar
Thread OP
I did remember to mark the hole for the retract mount, turns out the hole was not necessary since I had to add a couple plywood strips to get it deeper into the nacelle.
Those foam plates we counted on to set the motor angle has to be removed just aft of the balsa strip we saved earlier.
To remove only the material necessary to clear the wheels I wrapped the tire with sandpaper and rotated the wheels.
Sep 26, 2019, 03:29 PM
RC 4 Life
sparks's Avatar
Thread OP

Nacelle fit

Back to the fitting.
Lay the nacelle in place on the wing aligned with the nacelle mount ring.
Lay a marker or pencil on its side and draw a line to trim to.
Repeat this step until the front of the nacelle starts engaging the mounting ring.
As it gets closer to fitting; tip the pencil upward so the mark made will have you remove less material.

Rough sand the edge of the plastic and apply gorilla glue to the edge of the plastic.
Put the nacelle in place and clamp it to the mount ring with a rubber band.
Apply downward pressure with strips and let the glue foam and do its work filling gaps and forming a fillet inside the nacelle.
Sep 26, 2019, 03:33 PM
RC 4 Life
sparks's Avatar
Thread OP


In the first shot you can see a trim line near the base of the cowl half to the left.
On the cowl half to the right you can see a step in the surface.
When trimmed ; the trim line mates with the step in the opposite cowl half.
(Very hard to tool for )

Assemble your cowl with tape and try a test fit on the mount on the off chance that your foam ring “grew” somehow.
Now is the time that the aft end of the cowl is adjustable.

Glue these joints one side at a time so you can concentrate on the trim line matching the formed step. Do not use superglue . . . . once more . .
Do not use superglue. Model cement works best.

On a side note :
This is the first time I used my 3D printer to make a cowling tool.
It came out fitting very well and looking great.
There was a learning curve involved and it did great as a master tool but will not hold up for production parts.
Sep 27, 2019, 10:27 AM
Bronco Team Builder
Wade Joos's Avatar


Nice work
You are amazing
Sep 28, 2019, 02:25 PM
Electric Coolhunter
Thomas B's Avatar
Originally Posted by Wade Joos
Nice work
You are amazing
That is absolutely true. Sparky never ceases to amaze.

Looking forward to flying with him at BEST next week!
Latest blog entry: RC events for 2019!
Sep 30, 2019, 08:41 PM
Registered User
I like your Constellation build. The S3 Viking looks nice too. What nacelles did you use on your Viking
Last edited by CARL SCHIMNOWSKI; Sep 30, 2019 at 10:00 PM.
Oct 09, 2019, 06:20 AM
RC 4 Life
sparks's Avatar
Thread OP
After the Citation crash I had a pair of motors looking for a home so I started on the viking.
Motion RC has the replacement Nacelles on their site and they are not expensive.
Oct 09, 2019, 06:26 AM
RC 4 Life
sparks's Avatar
Thread OP

Belly fairing

While the cowls are having their seems filled with epoxy putty from west systems I thought I would work the wing to fuselage belly fairing.

That’s right, more sanding.

I used 60 grit sandpaper against the wing to turn it into a sort of sanding block.
Then rubbed a block of foam against it blowing away the bits as I worked.
Don’t think I sanded the whole thing I gave it a rough cut to get close first.

On the aft block I was able to get away with guessing at the size needed.
Note that both foam blocks have a balsa plate to mate with the wing saddle.
From this point I used thick paper taped to the fuselage as a sanding guard while the fuselage as used as a sanding guide.
(sanding guards and their use is in the book)
Oct 09, 2019, 06:31 AM
RC 4 Life
sparks's Avatar
Thread OP

Back to the cowls

I made small foam blocks the width of the scoop and started testing how thick it had to be to support the cowl level on the model.
Once happy I applied gorilla glue and bonded them in place. The tape is there to be sure it didn’t move.

I wanted to use just one screw in the top scoop to mount the cowl by taking advantage of the nice flat square shape the scoop makes up there.
It worked OK for a while but in the end I had to use two more small screws at the aft bottom edge at about the 4 and 8 o’clock position for a secure cowl.
Oct 09, 2019, 06:36 AM
RC 4 Life
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Thread OP

Motors & mounting

Agree or disagree but I kept mounting the motors simple.

I put a small tab of two-sided tape on the back of my motor mounts loosened the screws so it could come off the motor with a tug.

Next, I supported the wing with the front facing straight up. I lowered the motor into the cowl and centered the motor bell housing with the cowl inlet then pressed down.
The mounts stuck to the firewall and I was able to remove the motor and mark the firewall screw positions.
Since I knew the firewall angle was correct and the cowl position is correct all that was left was centering the motor with the cowl. it was just that easy.
Oct 09, 2019, 07:12 AM
Father by day, hacker by night
JornWildt's Avatar
Nice trick with the double sided tape. I've struggled with that operation on another model.
Oct 09, 2019, 12:30 PM
RC 4 Life
sparks's Avatar
Thread OP
Not very professional but so easy when the firewall is correct .
Oct 20, 2019, 05:45 PM
RC 4 Life
sparks's Avatar
Thread OP

Aileron Servo

The marks for the aileron was faint but I confirmed its position with the plans.
I placed the servo on the wing where I wanted it and traced around the servo.
I used a hobby knife to cut the hole being careful knowing there are wires there waiting below.
After powering up the servo and confirming the servo arm was centered I applied Silicone to the rib that will hold it and pushed it in place.
What I haven’t shown is that I taped off the surface so paint will stick later and pushed in a little silicone around the edges for a firm installation.

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