BBA/Winter Build 2017/18 - Top Flite Corsair

[nhk750]

Good stuff here, I'm getting ready to purchase paint for my fiberglass cowl and thinking about Rustoleum black with semigloss clear coat. So I will heat the cans up a bit. I want it slightly glossy but not to glossy. I wonder why your semigloss came out textured? I love the engine, awesome!

 

[wilmracer]

This is one of the times that I'm extra impressed with Joshua's build ethic. I completely agree with his decision, but it is a tough call to make. You're on a time crunch (we leave in 8 days), things are going well but still hectic, and then you hit a snag. The finish on the control surfaces was not terrible, but didn't have the level of perfection Joshua wanted. Most modelers I know would have just gone with it knowing that most people wouldn't notice the difference after final assembly. Joshua went to the time-consuming effort to strip the semi gloss and now has an evening or two of touch up to get these to the level of perfection he's looking for. That is a level of focus and dedication that deserves a lot of respect.

 

[willsonman]

Thanks, Carl. I always try to do things "the right way" not always the best way or the easiest. I'm just trying to get it done in a limited way. I have the time... I think, but only just. I still have a goal to try and get her back on her legs by the weekend. I'd like to get her out to the field for a taxi test, if the weather cooperates.

For my paints, I keep them indoors as I have had lots of paints go bad over winter months and it frustrates the daylights out of me. It's possible the nozzle could have just gotten improperly cleaned after my last use last year when I finished the Bugatti. The finish on the Bugatti certainly does not look as poorly textured. Either way, the shine was just too much anyway for the look I wanted. Had it not been so textured I would have just shot the matte over top and been done with it.

 

[rockyboy]

Do your warm your paint cans before spraying? I seem to recall you saying you do, but if not, sometimes splotching results from the paint being too cool and/or the propellant too cold to develop adequate pressure.
Simply setting your can in a bowl of hot water for 10-15 min. can make all the difference. When you take it out and shake it, it should feel warm. If not, let it sit a while longer.

Thanks for the tip - with temps back in the 40's here I'm going to try that tonight!

 

[Tench745]

I do it even when my paints have been kept inside. Pick up a can of paint from your shelf, it will nearly always feel cold to the touch. In my experience, warmed paint always sprays better, even with a partially gunked-up nozzle. I've had mixed results with Rustoleum and Krylon matte. They always turned out a bit too grainy for my taste, but then I was spraying it on 1/48 scale models.

Little side-story, I had a really hard time finding a "flat" paint that wasn't Testors Dullcote. After a bit of research I found out there is an industry standard for what amount of reflectivity qualifies as gloss, semi-gloss, matte, and flat.

 

[rockyboy]

After spraying some Krylon "ultra flat white max-cover primer" tonight and getting the thinnest possible color with massive bleed through even after three coats, and then a Krylon Satin White that dried super shiny, I'm really sick of the paints at my local hardware store.

I love how the Ironlak Sugar line of spray paints went on and will bite the bullet and order more. They are very opaque, give fast even covering, and very flat finish - but they are also betwen $12 and $15 per can. Oh well, you get what you pay for sometimes.

 

[willsonman]

Part of the reason I use the interior paints is how evenly they go down. The latex/acrylic makes for a nice finish that is rather flexible from expansion/contraction in temperatures but it has to be thinned to shoot it through an airbrush which means you HAVE to apply multiple coats. Not really a big deal as it get the perfect results and being thinner... it dries fast with the hair dryer. I thin my paint with windex with at least 60% windex in the mix. I have found that 50/50 (or 1:1) is too thick and will clog my airbrush.

Parts are re-painted and the canopy as well. There is a way to tell that they have been re-done but I'll keep that to myself.

 

[willsonman]

In reviewing the list...

Clear coat
Pretty sure I can get this done in one evening. Weather is expected in the 60s so I'll be pushing to get this done as soon as I get home from work.

Canopy installed
Its 4 holes in the canopy and screwed in. How hard can that be! LOL

One more oleo and wheel paint
work out linkage for the boost tab on the elevator
battery tray
install battery hatch with hinges and magnets
All this should take one evening so probably tomorrow.

reassemble cowl flaps, dummy radial, cowl
glue in ALL control surfaces (includes re-connecting linkages, and checking for centering)
finish bombs
CG check/ weight check
Currently scheduled to be done on Friday.

Taxi Test
Saturday. The weather looks half-decent to actually fly it but it will be a cold morning and the wind will likely pick up by the time it warms up. We shall see but I'm not going to push my luck. I really just need to get her on her legs and do a shake down.

 

[willsonman]

Clear coat application:

Got it all done in about an hour. The sun was out with a slight breeze. I used the hair dryer as well in spots to accelerate things but I left it all in the sun for an hour and a half and it was perfect to touch and handle.

Small parts


Wing showing amount of reflection. Enough but not too glossy.


Showing color.


Fuselage side


And the other. I like the shine a lot in this picture at the front end.


The money shot. All that hard work on details peering through. Enough to grab your attention from a distance and when you get close it sucks you in further.


De-masked the canopy. No overspray on the clear parts.

 

[willsonman]

You didn't think I was done, did you?

The wing control surfaces are all installed. I used TitebondII so I wanted that to cure overnight before I made adjustments to centering and such. The flaps were tricky but manageable as the set of three have to be installed as one flap... six hinges plus the internal control rod.


Cowl flaps had their control ring rod re-installed. Screwed in and servo horns screwed in. The dummy radial was bolted back on... still on true center. The cowl was also installed along with the prop and spinner.


Tail surfaces installed. Each surface has three hinges along with the internal linkage arms.


The canopy was cut and the front portion was glued. I use Formula 560 canopy glue as it dries clear but I roughed up the inner lip of the canopy for more grab. I also used a needle to poke small holes through the primer/paint to allow the glue to have more grab. Rear portion is in rough position... not installed at all yet.


Not to be overlooked, I got the ordinance assembled. I opted out of yellow stripes as I did not like the look of the green/yellow with the blue. It will make them VERY hard to find but I can always 3D print more.

 

[willsonman]

To-do list update:

Rear canopy installation.
One more oleo and wheel paint
Touch up paint on tail gear
work out linkage for the boost tab on the elevator
battery tray
install battery hatch with hinges and magnets
CG check/ weight check
Oil cooler grills (remembered this one last night)

Most of this can be done tonight but not likely to get it all done. The canopy glue can take DAYS to dry so I'll likely not even consider finishing the canopy for at least another day but I will check the glue.

 

[rockyboy]

Spectacular!

Love seeing it come together :applause:

 

[Joker 53150]

Lookin' good! The detail level in the pics appears to be spot-on, and the only problem I have is laughing every time I see the big BM. But that's just me being childish.

 

[willsonman]

Yes, Mr. Bowel Movement... Again... Bob MaHaffie. I hafta say also that I'm just getting giddy over going to SEFF. It is going to be a great time.

 

[Grifflyer]

Amazing work, I love the level of detail!

 

[jaredstrees]

Wow, I go away for a week and miss a ton. Looking fantastic!

 

[willsonman]

Crossing the SEFF finish line here folks...

Battery tray installed at an angle. The horizontal former acts as a front hold-down for the top of the batteries and I used a piece of triangle stock on the top and aft portion as a means of allowing the screws to angle into the ply plate. I'll likely be putting holes in this to shed some weight but its in there and two screw to remove it makes it easy. Needs a strap too.


Boost tab linkage. Yes, its bulky. I opted for something more robust out of safety concerns. If something were to break or even come loose it would cause some flutter in the elevation plane. Never a good thing. Still, its there and something I've never done before.


Battery hatch has two pin hinges. I cut a small recess into the wood and used CA to secure the hinges. Cut the excess so that my meaty hands will not catch on anything and rip them off. Additional trimming on the hatch allows perfect open-closure with zero binding. Single rare earth magnets on the fuselage and hatch hold things together.


Here, I've installed the wing to start a systems check and open up the gear doors to install the oleos (both are painted now). You can see how the hatch is fairly well-concealed with the slight gap looking more like a panel line. Just a few touches of paint on the hinges completed the look.


Whats left? Well I got all the paint touch ups done and I'm really happy with how she is turning out. I did plug her in and noticed that the cowl flaps needed a quick adjustment. Pop off spinner, prop, cowl and it was done. Tail gear retracts perfectly. I need to label things a bit better... I plugged in the main gear doors to the bomb drop channel. and somehow did not plug in the bomb drop. I think I'll also cut the nylon bolts as they are really long and the extra length serves no purpose. I did bust out the scale but it was acting up and I do not trust the reading so I'll look in on weight later.

So with all of that I have just a few things to do this evening.

Rear canopy installation
Oil cooler grills
Systems check/ CG check/ weight check

The rear portion of the canopy will take some time. I need to fabricate some brackets that will be epoxied to the lower front of the canopy to bolt onto the slide mechanism. The rear guides will be easy once that is done. Just a couple of holes and epoxy the guides in place. A few odds and ends here and there but nothing major.

 

[wilmracer]

I'm really interested in the boost tab linkage. I've also never done one and yours looks great. I'm certain you've checked already, but it doesn't bind at all at your intended high-rates/full-throws, right?

 

[willsonman]

I'm glad you asked about this. So basically this is a geometry issue. You need enough height to clear the linking rod and the control surface. So when the elevator goes up, the tab goes down and you can bind at the trailing edge of the rod. When the elevator goes down, the tab goes up and the binding can be at the leading edge of the rod. The key is to make sure the height of the hole for the linking rod is the same at the front and back to make the tab even with the elevator. in all respects. Getting the mounts at the far trailing edge of the H-stab and the leading edge of the tab will help a lot to prevent binding. Also, the thickness of your rod. I wanted this to be a bit more flush and the oly way to do that was to use a smaller linking rod. Something that I did not want to do. I could have just used a simple rod with some z-bends in it but I did want it to be serviceable. I had considered using a threaded rod with a z-bend on one end and a clevis on the other but thought it looked ugly... too RC and not scale. ANother option was just 90-degree bends at the correct location and use plastic keepers but I did not have any.

Hope that answers your question.

 

[rockyboy]

Here's some neat stuff on the geometry of boost tabs from the 1943-1945 patent filings

https://patents.google.com/patent/US2370844

Had no idea about these things before! There is also a balance tab that is similar in construction but where boost tabs are usually powered, balance tabs are controlled by static linkage and the control surface is powered.