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Jul 07, 2018, 08:02 PM
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bstanley72's Avatar
Here's an update on mine.

Iíve struggled here. I donít have a great deal of experience painting and Iím having problems under spraying my masks. I used regular blue painters tape when laying down the red, and you can see it bled onto the white. I got some frog tape and used it for the straight lines with black, this mostly solved it. However, the lettering is an issue. The best way I could come up with on the lettering was to print them out on photo paper and then use 3M77 to stick them down. Iíve done this before, and it worked pretty well. But not here.

Iím certainly open to suggestions on what to do at this point. Iíll try touching up the white tomorrow with a small modeling brush and see where that gets me.


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Jul 07, 2018, 09:22 PM
No RTF flies like your own SB
mperaltaoz's Avatar
Hi Bstanley72,

I saw your photos and the underspraying on the straight lines seems relatively easy to fix with touch up paint so you shouldn't have any problems there. This happens to me a lot and I always fix it with touch ups.
The letters are a different story...

I never paint letters or decals in general.
What I do is to print them out in standard white paper with a colour laser printer. I then cut and apply them to the plane with WBPU by giving a coat to the area and the back of the decal, laying it in place and then going over it with a foam roller. The area and the decal must be wet enough for them to keep together.
It is important here to use a foam roller and not brushes as they will peel the colour from the decals.

Once all the decals are dry I cover the plane with a couple of coats of WBPU for a nice finish. Decals look like plastified and keep in place very nicely.

For this plane I applied the Critical Mass decals as they are in the file by cutting them as two words. You could do the same or stick them letter by letter (more work).

Looking forward to see the outcome!

BTW love your working area. Mine is a mess 99% of the time and my wife keeps nagging about it
Jul 07, 2018, 11:35 PM
Build straight - Fly twisty
Whiskers's Avatar
A thing that can be tried stop paint from seeping under masking tape is to first spray the edges with the same colour as the background.
So in your case you'd mask up to do the black letters and then spray the edges with white, when the white paint had dried you then spray the black paint on to the letters,
The theory is that the white paint does the bleeding, does not show in the final result, and prevents the black from getting beyond the mask.
Jul 08, 2018, 06:49 AM
Went to mow a meadow
frank48's Avatar
Plus one ...

You can also spray the edges of the tape with some clear WBPU or similar and this will seal off the edges
Jul 08, 2018, 08:03 AM
Registered User
bstanley72's Avatar
Mperaltaoz,

Your decal trick is what I plan on doing for the Taco Bell Logo, Tasmanian devil etc. Now wish I had done for the letters as well!

Whiskers, that's a good idea, makes complete sense. Wish I had thought of that before!

The good news is it looks great from 10 feet away, and I'm more of a does it look good in the air kind of guy. But, it still bugs me a bit. I'll try some touch up paint and see where that gets me.

Thanks fellas!
Jul 08, 2018, 09:14 PM
No RTF flies like your own SB
mperaltaoz's Avatar
If you are touching up white, do yourself a favour and get a sample pot of ceiling paint.
It is much better than any acrylic paint when it comes to covering other colours.
Jul 09, 2018, 08:31 AM
Registered User
Captain Dunsel's Avatar
You can also cut letters, etc., from Oracover/Profilm/Ultracote and iron it on, over the paint. Just keep the temp at the lower end of the setting (about 220F, I believe).

Likewise, you can buff the covering film, spray paint it, then iron the painted film on over the painted surface. Again, the key is to keep the iron just hot enough to soften the adhesive, whilst not hot enough to melt the paint or the foam.

CD
Oct 11, 2018, 06:07 AM
No RTF flies like your own SB
mperaltaoz's Avatar

Split flaps and scale canopy


Hi there,
I just gave the Critical Mass another upgrade...
Split flaps and a scale canopy made with my new vacuum forming machine.
I haven't flown her yet, but the flaps look pretty good.
Hopefully I'll test the this weekend.
Oct 11, 2018, 06:38 AM
Build straight - Fly twisty
Whiskers's Avatar
Fan-bloody-tastic mate!
Oct 11, 2018, 05:38 PM
Registered User
bstanley72's Avatar
Here's mine pretty much ready to go.

Mperaltaoz, where do you balance yours? Mine came in pretty tail heavy and I have added a fair amount of nose weight to get it to balance at about 28% back on the leading edge. Wing is 290 mm at widest part, so I'm balancing it at about 80 mm. Mine is a bit bigger than yours coming in at about 1350 mm wingspan.

It's so heavy I'm worried about it flying. All up weight is about 3,475 grams with a wing area of about 3,400 square centimeters. This is giving me a wing cube loading of 17.6, far into racer/warbird territory. It is heavier with a smaller wing than my FMS 1400 Mustang, so this concerns me. I've actually considered stripping the electronics out and making it a static model hanging from the ceiling in my shop, but I just don't think I can do it. I built it to fly, and I want it to! I think I definitely made the newb mistake of overbuilding things and coming in heavy.

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Oct 11, 2018, 09:59 PM
No RTF flies like your own SB
mperaltaoz's Avatar
Hi Bstanley72,

Wow! That plane looks amazing... well done!
Let me try and help you there with some calculations.

Mine is 1116mm wingspan and it's weight w/o battery is 1400g (with battery about 1650g-1750g depending on whether I use 2200mAh or 2700mAh).
The CG is 90-100mm from LE measured as in the photo below.
The wing area is 26.5dm2 which gives us a wing loading of 66 g/dm2.
The power train is 4S, 790Kv motor with a 12x8 propeller which pulls about 2.7kg thrust and 700W power.
She flies really well, and lands well too (although a bit hot sometimes, reason why I recently added flaps).

Yours being 1350mm wingspan, it means that you've scaled it up approx. 21% bigger, or 1.21 as a multiplier.
With those numbers, your AUW should be 2117g (2.1kg) for similar characteristics I guess...
If you followed the same proportions, your wing area would be 38.8dm2. So, at 2117g the wing loading would be 54.6 which is nice and low... but at 3475g it would be 89.6g/dm2 -> that sounds definitely too high.

I've got a Hall Bulldog Racer 1300mm wingspan with a wing loading of 77g/dm2 and it is a handful to land. She comes hot every single time

Re CG, I guess yours should be at 108mm-121mm from LE.

I think you might have a weight problem there... Is there anything you can do to remove some weight?
If not, I'd suggest to definitely add flaps (as landings would be very hot otherwise) and give it a try like that.... or as you said, keep this one as a display model and build a lighter one!


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