F4F-4 built as FM-1 Wildcat by Landlubber Mike - FINISHED - Tamiya - 1/48

[Landlubber Mike]

6 hours ago, Egilman said:

Two words Brother, Panel Scriber.....

 

Use it just like you would to scribe panels but continue on through the part for seperation..... with the scriber you can cut the oblong shapes out in one piece as well....

 

One other thing brother, they wouldn't droop on a carrier deck..... The control surfaces would be mechanically locked to prevent flutter damage from the wind when sitting on the deck....

 

Thanks everyone for chiming in here!  

 

I have a few panel scribers, and while they work great, they are triangular in shape down to the blade so what I've found happen is that you end up scribing out an increasingly wider section the deeper you go.  Given that the elevators are probably 3mm thick, if not a little bigger, the kerf (not sure if there is a more appropriate term when scribing) was getting to the point where it was just easier to mill them out with a micro milling bit.  Are there others that are more scalpel like in application?

 

As for the drooping, while there was a hand crank, I don't know whether they were mechanically locked or not.  I found a number of pictures suggesting that both the ailerons (damn, I suck at terminology and I just talked to Lou the other day who corrected me) and the elevators did droop.  Here are some pictures of different Wildcat variants, for example, from the Squadron In Action book on the Wildcat.  

 

 

 

 

 

 

Some other random pictures I have on file as well (first might be an F6F Hellcat, but likely similar engineering):

 

 

 

 

At this point, I'm not going to change things.  It was a little tricky getting them to sit in the position, but what I finally did was use CA, and once dried, followed up with a very thin line of two-part of epoxy along the underside seam.  I was worried that CA can be a little brittle and I'd likely knock one or all of them off at some point in the future, so the epoxy gives me a little more peace of mind.  So, I think they are stuck there, whether correct or incorrect 😐

 

Edited January 6, 2021 by Landlubber Mike

[lmagna]

Also, in regards to your "flaps", yes they are really called ailerons and normally work in opposite directions forcing one wing upward and the other downward at the same time. This is not always true with some modern aircraft but we are talking about the F4F not some 21 century super fighter. At any rate while it is true that this is how they worked on the Wildcat, they also assumed the position you have placed them when the wings were folded.

 

 

So if your intent is to model the plane with the wings folded you are right as rain in their position.

 

WHOOPS! Sorry Mike, didn't see your above post before posting my mediocre example. 

Edited January 6, 2021 by lmagna

[Landlubber Mike]

Lou thank you!  And your example is better than mine - great picture!

 

The picture is also great for showing how many more planes could be carried by a carrier.  The wingspan of the F4F-4 was 38 feet.  When folded, the wingspan was reduced to 14 feet 4 inches.  That enabled the Navy to increase the number of fighters assigned to a squadron from 18 to 27.  American ingenuity!

 

In looking at the Squadron book, apparently the early F4F-4s - which were designated as the XF4F-4 - were made by Grumman to include a hydraulic wing fold system.  During tests, the weight of the aircraft made it inferior to the F4F-3 when it came to speed, climb, and maneuverability, so the final production of the F4F-4 came with the lighter manually folded wings.  

 

 

Edited January 6, 2021 by Landlubber Mike

[Egilman]

 

1 hour ago, Landlubber Mike said:

Are there others that are more scalpel like in application?

Yes Mike, All scalpels are knife cut meaning both sides of the blade have an angle.... There are some panel scribers that are square and cut a flat bottom groove.... Those are the ones used for separating panels....

 

Micro-mark panel scriber

Edited January 6, 2021 by Egilman

[Egilman]

2 hours ago, Landlubber Mike said:

As for the drooping, while there was a hand crank, I don't know whether they were mechanically locked or not.  I found a number of pictures suggesting that both the ailerons (damn, I suck at terminology and I just talked to Lou the other day who corrected me) and the elevators did droop.  Here are some pictures of different Wildcat variants, for example, from the Squadron In Action book on the Wildcat.  

The hand crank for the flaps was purely mechanical in operation, and as you look at your pics and Lou's pic, all the flaps are completely closed when the wings are folded......

 

If you notice in the pic of the Wildcat being parked on the deck, (and the video I posted earlier in the thread) the pilot is still in the aircraft and the engine is running while they fold the wings, all the control surfaces are in neutral position cause the pilot is holding them there.... After the wings are folded and the aircraft is pushed into position on the deck the pilot leaves the aircraft and the crew chief installs the control surface lock which is a device that consists of a ring that goes over the control stick and has four elastic, (think bungee cord) straps with hooks on the ends that are hooked to spots in the cockpit to prevent rapid and violent movement of the control surfaces... Without it yes the elevator would hang down at the limit of it's travel...... What your seeing on the parked 'cats is the slight droop the the elastic cord allowed them to hang..... Probably from well used control lock devices with a bit of slack.... 

 

As far as the ailerons go looks to me that you got it right, that's not a detail I even noticed before, probably stems from them being mechanically linked and when the wings are folded the pivot point for the Aileron linkage is in a different location than the pivot point of the wing panel itself essentially causing the ailerons to move in the same upward direction when the wings are folded, it is clear from the pics (and video) that while the pilot is in the aircraft the surfaces are in neutral position....

 

The Grumman sto-wing folding system

 

Grumman developed three different ways to do it, but the one first used was used on the Wildcat and subsequently used an other aircraft.... And yes the aileron connection was mechanical and had a different pivot point (and method of pivoting) than the wing panels hinge point.... Not all wildcats had the same system and some Ailerons did deflect like the FM-2 other earlier versions did not....

 

Thanks for bringing up the point and giving me the desire to research it...

 

You are correct, they took that upward and outward slant when completely folded.....

Edited January 6, 2021 by Egilman

[Danstream]

Hi all. just one little note in addition to the discussion above:

3 hours ago, Egilman said:

Without it yes the elevator would hang down at the limit of it's travel......

Actually, hinged control surfaces (i.e. elevators, rudder and ailerons) are statically compensated. In other words, there are balancing masses - located inside or visible outside - that bring the center of mass ( or center of gravity if you want) of the surface to lay on the hinge line. (this is done to avoid that inertia forces trigger unwanted dynamic effects on the controls). Therefore, once left alone, control surfaces remain in their last position and are not influenced by gravity. Now, in most of cramped cockpits, before getting off, the pilot often pushes the stick forward to make room for his legs. This results in the elevators hanging down in most cases before the ground crew take the plane under their care. Other times, if a control locking device is not at hand, the control stick gets tied up using the seat belts and this might often results having in the elevators pointing up.

I though you might have been interested about the above and it is not my intention to appear pedantic.

Kind regards,

Dan.

 

Edited January 6, 2021 by Danstream
Typos corrected.

[Canute]

Using good, clear photos is your best source or evidence. They prove (or disprove) all our conjectures. Good research helps us build accurate models.

[Egilman]

1 hour ago, Danstream said:

Actually, hinged control surfaces (i.e. elevators, rudder and ailerons) are statically compensated.

One more little detail... For aircraft designed after 1940 your correct...... Prior to that Aircraft hadn't hit the compressibility wall..... Balanced control surfaces, (at least for US aircraft) came out of Lockheed when they were working out the problems of compression stall and elevator lockup at high speeds with the P-38... They found that counterbalanced control surfaces counteracted most of the bad effects of compressibility.... (not all of them though)

 

The F4F, FM2's and the like were designed well before that, The Hellcat had hydraulically compensated control surfaces but the wildcat did not have such... It was the last of the seat of the pants, fully manually controlled fighter planes.... Besides it wasn't fast enough to reach compressibility in any flight regime.....

 

Ever....

[Egilman]

56 minutes ago, Canute said:

Using good, clear photos is your best source or evidence. They prove (or disprove) all our conjectures. Good research helps us build accurate models.

Absolutely Ken, all else fails, check the pictures....

[Danstream]

Dear @Egilman, you are correct, however, the static balance of the surfaces was not introduced because of compressibility effects, but to avoid dynamic effects (dynamic couplings). You can see, f.i.,  balancing masses when mounted externally to the wing in aircraft as early as the Ju-87 or the Bf 109. It is true that I do not know the exact date for their introduction and I will see if I can find a more precise information.

Greetings,

Dan.

Edited January 6, 2021 by Danstream
clarifications

[Landlubber Mike]

7 hours ago, Egilman said:

 

Yes Mike, All scalpels are knife cut meaning both sides of the blade have an angle.... There are some panel scribers that are square and cut a flat bottom groove.... Those are the ones used for separating panels....

 

Micro-mark panel scriber

 

Thanks!  I was using some from UMM that have an angle.  I'll have to try these out.  I actually have similar dental tools my brother gave me that I might try as well.

[Egilman]

10 hours ago, Danstream said:

the static balance of the surfaces was not introduced because of compressibility effects, but to avoid dynamic effects (dynamic couplings).

Actually Dynamic Coupling is a compressibility issue on an aerodynamic basis... Compressibility first shows up in control surface flutter... This is where the air pressure building up along the leading edge creates turbulence along the surface, when the turbulence reaches the control surface, they start to flutter.... (flap like a flag in the breeze) As airflow (speed) increases, the center of pressure bleeds back along the surface and pushes the turbulence past the end of the control surface, flutter stops and what is called dynamic coupling takes over, the pressure of the flow of highly compressed air overcomes the control moments mechanical leverage and they seem to lock up, the pilot doesn't have the strength to force the controls to move against the pressure stream.... Another obscure name for this is control surface weathervaning..... the control surfaces follow the flow of air......

 

So yes Dynamic coupling is a compressibility issue.... The faster the airplane goes thru the air, the stiffer the controls become, until the pressure is built up enough that the controls seem to lock up to the pilot...

 

Hydraulics alleviated this problem for a few years, (hydraulics can easily apply ten times the force a man can to the control surfaces) But, as airplanes kept getting faster and faster, compressibility rears it's ugly head again and again... Eventually NACA developed the Area Rule, (a revolution in aerodynamics) which ended the problems of compressibility by creating space along the surfaces of an aircraft in airflow to allow the airflow to decompress before passing over the control surfaces....

[Canute]

Also developed the all moving horizontal tailplane or stabilator(stab). Re-positioned it to get it out of the airflow behind the wings.

[Egilman]

1 hour ago, Canute said:

Also developed the all moving horizontal tailplane or stabilator(stab). Re-positioned it to get it out of the airflow behind the wings.

Absolutely Ken, that was a natural outgrowth of getting the control surfaces out of the compressed airstream....

 

One thing Dan brought up was counter balancing control surfaces to prevent dynamic coupling....

Adding counter balances to elevators on aircraft was first done to control flutter... The mechanical effect was to increase the mass of the surface so it would be less effected by turbulence.. when they realized that there is just so far they can increase mass before they affect controllability, so they went to mounting the extra mass ahead of the control surfaces pivot point, (counterbalances) This had the effect of increasing mass without increasing the required force to move them... It also had the effect of taking less pilot input effort to move the control surfaces making the aircraft super responsive.... In essence it increased the mechanical advantage of the controls, which of course made the aircraft able to fly faster..... (greater stability in the control surfaces allow faster airflow over the surface, hence the airplane can fly faster)

 

But like everything else it had it's limits and the mass of pressurized air would also increase as the plane flies faster until the point that no amount of mechanical advantage could overcome it's effect...

 

This is what happened to both the P-38 and the Corsair as originally designed..... The counterweights and widening of the elevator on the Lightning overcame most of the compressibility effects except at the most extreme edge of the speed envelope... Moving the elevator pivot point forward and adding hydraulics on the Corsair overcame the flutter problems associated with it's prototypes....

 

It was all a learning process, the advancement of engineering and the understanding of dynamic the processes involved.... These aircraft were designed to fly right out to the edge of the flight envelope....

 

And one of the most amazing things to me, is all of it, engineering and advancement of science, can be directly related all the way back to the Wright Brothers....

 

[Canute]

They were the model for all aerodynamic study. They invented or better developed a model wind tunnel and pushed the engineering of smaller, higher horsepower engines. And they used wing warping to turn the a/c. I remember NASA doing tests in the 80s or so, investigating adaptive wings which weer essentially warped wings. Glenn Curtis and co developed the ailerons, which were easier to adapt to the wings back in the day. The Wrights were geniuses.

[Egilman]

Yep, Inspirational genius's..... 

 

Took them ten years to prove in court that Curtis's ailerons were just a different mechanical interpretation of their patented inspiration on how birds controlled their flight....

The unfortunate thing is it cost them their company and world wide leadership in aeronautical design.....

 

By the time they got back into designing airplanes they were so behind the curve they could never make up the lost time....

The list of their contributions to flight is very long, starting with the creation, (out of thin air so to speak) of the whole science of Aeronautics...... They were the first to understand what was happening with wind flowing over a wing and how to adapt it for control.... Most of the terms used to describe it were coined by them, they established aspect ratio as a measure of lifting capacity for a given airfoil shape and with their invention of the constant velocity wind tunnel, what that capacity was in real world terms.... The proper form of a propeller was a rotating wing which would actually provide thrust rather than just move air.... The list is almost endless.... They hand carved the most efficient propellers ever made... (78% efficient even modern engineering hasn't come close to matching that even today)

 

Hundreds of books have been written on what they accomplished, but most do not know, the public sees them as the first to fly, the more educated understand they were the first to build a truly three axes controllable airplane.... (they designed the Wright Flyer deliberately to the absolute edge of controllability to prove it, as unstable as possible and still be able to fly) And that is only 1% of what they accomplished... 

Edited January 7, 2021 by Egilman

[Landlubber Mike]

Well, it's taken me a while to get here, but finally got the fuselage primed.  Woohoo!

 

 

I love using Mr. Finishing Surfacer right from the can.  It dries (very quickly) in almost a baked on consistency and can be sanded, unlike Vallejo which is prone to peel.  Its leveling properties are almost magical.  I had a spot where too much spray had accumulated so I was preparing myself to have to strip it off and re-spray, but I came back a half hour later and everything was perfect.  The gray is nice because it highlights any flaws or other issues that need correcting.  Fill, sand, re-spray -- piece of cake.  Highly recommend it.  Really stinks though, so make sure you have a spray booth with exhaust or a nearby window.

 

 

I'll inspect for any issues tomorrow, and then I might be able to get the base colors on.  I'm still considering black-basing the entire plane, then slowly coming back to a white underside and gray topside.  Will have to sleep on that one though.

Edited January 8, 2021 by Landlubber Mike

[Old Collingwood]

Very tidy smooth finish Mike.

 

OC.

[Landlubber Mike]

Thanks OC - I have to say, this primer really does all the work.  

[Old Collingwood]

Just now, Landlubber Mike said:

Thanks OC - I have to say, this primer really does all the work.  

Tamiya surface primer  give me good results  - just needs spraying out doors though.

 

OC.

[Landlubber Mike]

I spray mine in a booth that is vented out a window.  The booth is in my basement, and this stuff still stinks up the joint.

[Old Collingwood]

1 minute ago, Landlubber Mike said:

I spray mine in a booth that is vented out a window.  The booth is in my basement, and this stuff still stinks up the joint.

The sacrificies we make not using Acrylic....

 

OC.

[Canute]

I believe those primers are lacquers, hence the stink/odor.

[Old Collingwood]

2 hours ago, Canute said:

I believe those primers are lacquers, hence the stink/odor.

Indeed Ken.

 

OC.

[Landlubber Mike]

I'm a big fan of acrylics, especially when it comes to clean up.  I hate cleaning out my airbrush after using Tamiya or other lacquer/acrylic lacquers.  What I've found, however, is that Vallejo primers can pull up when taped, especially when painted on metal surfaces.  For areas like the cockpit where I won't be taping, I use Vallejo primer just because it's easier.  For areas like car bodies, plane fuselages, etc., I think the lacquers are a much safer bet.

[Old Collingwood]

8 minutes ago, Landlubber Mike said:

I'm a big fan of acrylics, especially when it comes to clean up.  I hate cleaning out my airbrush after using Tamiya or other lacquer/acrylic lacquers.  What I've found, however, is that Vallejo primers can pull up when taped, especially when painted on metal surfaces.  For areas like the cockpit where I won't be taping, I use Vallejo primer just because it's easier.  For areas like car bodies, plane fuselages, etc., I think the lacquers are a much safer bet.

Do you find you need to give the Vallejo primer a good few days to harden before putting paint  layers ontop?   I find if it hasn't had enough time its still soft and scrape off with a finger nail.

 

OC.

[Landlubber Mike]

With any brand, vallejo, Mr. Finisher, etc. I generally leave on my primer coats undisturbed for at least 24 hours.  I've had Vallejo peel even after that period.  For example, on my last build, I had used Tamiya tape inside the cockpit to help seal it when painting the fuselage.  It pulled the paint and primer off the instrument panel - which probably had been primed and painted weeks before given the rate I build.  I can't recall whether the paint that was pulled was off plastic or metal though.  

 

On metal, Vallejo primers don't seem to have very good adhesion.  The Vallejo primer I used on the PE frames for the open panels on this build scraped off fairly easily, and I've had that happen a number of other times.  Maybe I haven't pre-treated/cleaned the PE frets enough, or maybe oils from my hands left a film on the PE, I don't know.  I picked this up a while back but haven't used it yet.  I might try spraying the PE frets down with this stuff first to give a better base for Vallejo to stick to.

 

 

Of course, it's totally possible all this is due to user error, which, if you ask my wife, normally ends up being the case.   

Edited January 8, 2021 by Landlubber Mike

[Canute]

On metals and resins, a swipe with acetone or denatured alcohol should clean most of that. I've washed resin boxcar kits in Dawn and warm water (not sealed up though) to remove mold release, plastic/resin dust and finger prints.  Dry the kit, but don't touch it with bare hands after that. Rubber gloves are fine.

 

Sometimes you may need to etch brass. Usually some kind of mild acid, such as white vinegar, does the trick. A short bath should do (5 min). Again, don't touch with your bare hands after you've cleaned it.

[Old Collingwood]

1 hour ago, Canute said:

On metals and resins, a swipe with acetone or denatured alcohol should clean most of that. I've washed resin boxcar kits in Dawn and warm water (not sealed up though) to remove mold release, plastic/resin dust and finger prints.  Dry the kit, but don't touch it with bare hands after that. Rubber gloves are fine.

 

Sometimes you may need to etch brass. Usually some kind of mild acid, such as white vinegar, does the trick. A short bath should do (5 min). Again, don't touch with your bare hands after you've cleaned it.

I did an experiment  (by accident)  to test the different hardness of the different vallejo products  - in my mixing  saucer I use  (its a plastic plant  one pinched from the garden)   anyway  after a couple of days I clean it using hot water under the tap and a wire scourer  - I found that the vallejo primer really resisitant to clean off  and the same with Black  and Grey, the Reds and Blues   and Brass  and Alum colours  are more easily removed  - so that tells me after a couple of days  the primer does need that time to fully harden  but when it does  its solid  same with the Black / Grey.

 

Well thats my science bit out the way.

 

OC.

[Lt. Biggles]

Looking forward to seeing the process you use for building up the colours! If not too much trouble can you post pics of each stage? As I’ve not painted a plane with an airbrush before so am on the learning path! I think for mine I’ll black base and layer from there. Such fine lines of over doing, under doing, over weathering, under weathered!