Scale Improvements For Mustangs

These suggestions are directed mainly toward the Top Flite GS Mustang which is the most popular of the sport scale Mustangs currently available.  However some of the comments apply to other Mustang kits on the market as well.  It's my personal opinion that no matter how well the surface painting and detailing is done, it's not quite as impressive if the outline and shape of the model hasn't been optimized first.  However, scale is like beauty - 'it's in the eye of the beholder'.  So it's a personal choice. 

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Basic Changes

Stabilizer Tip - this one is easy.  On the the Top Flite GS specifically, the tip in the top view is too rounded.  (The vertical stabilizer is OK.)



Metal vs. Fabric Covered Elevators - starting in Feb, 1945 production P-51D's had metal skinned elevators (the rudder retained fabric covering).  Many restorations have gone to metal elevators.  So to be as scale as possible which type of covering should be checked using photos of the specific Mustang being modeled


Dorsal Fin – it should be triangular in cross section and have a constant small radius all along the straight portion.  At the start of the curve to meet the vertical stabilizer the radius increases until it blends with the leading edge of the vertical.



Pilot Size – So many I see are much too large.  Rather than go by the stated scale for a pilot figure, use photos of pilots in full size Mustangs to help get the correct size.  Note that most pilots flying restored Mustangs wear crash helmets which makes their heads look larger than if they were wearing leather helmets .  Also note that the top of the pilot’s head will usually almost touch the canopy – the better to see better over and around the long nose no doubt!

(This is also an almost perfect side view of the spinner profile.)



Horizontal Stab – it's 5/8" too low on the Top Flite GS ARF / RTC kits – (but is correct in the builders kits).  It's easy to scratch a fix or I have an inexpensive kit to raise it.


Wing Fillets – All you have to do is compare those in the kit to a photo of a full scale Mustang to see they can use improvement.  Most who replace them build them up using various methods.  RC Universe has had several threads about this.



Tailwheel – it should retract forward.  Sierra has a couple of sizes that retract correctly.

Underwing Scoop – the overall shape needs improvement, especially the intake opening.  (I plan to have a fiberglass replacement in the near future for Top Flite GS Mustangs.)




Canopy – the kit windshield is not very scale-like and the rear of the canopy is much too pointed.  And the windshield and canopy sections are not faired into the fuselage as they should be.  Note the shape of the windshield bow and the side windows below.  Finally, using screws to attach it seems to accentuate the impression that the canopy is just tacked on. 

The Aerotech canopy for the Top Flite GS Mustang fixes these shortcomings and was available with a sliding option.  However as of Sept 2012 Aerotech accessory line has been sold and it's unclear if this canopy will be available in the future.



Main Gear Struts – The full scale Mustang's upper main gear legs are 4" diameter. To be the correct size the kit’s should be 3/4" diameter.  Some builders have "sleeved" the upper struts with aluminum or brass tubing to improve their scale appearance.



More Difficult Changes

Cowl - almost none have a large enough spinner and a realistic shape, particularly in the area of the intake scoop. 


Spinner - None of the commercially available spinners are exactly the right shape.  Beyond the contour, most of the popular spinners are as long as their major diameter.  However the Mustang's spinner's length is shorter than it's diameter, making the most of the spinners look like they were taken off a turbo prop.  Here's a comparison of the the available 'Mustang' spinners in 5 to 5-1/2" diameters.


 Dihedral – the Top Flite GS kit has a little over 1/2 what the full scale Mustang has and it's very apparent once you’ve seen a full scale Mustang.  Specifically the full scale wing panels have 5° dihedral measured at the center of the 25% chord line.  Putting 5° in the trailing edge would be very close.  Although the effect of this change hasn't been reported to my knowledge, theory and other Mustang kits with the right dihedral suggests it will not affect normal flight, that it will improve stability slightly in landing mode and that it may be slightly detrimental to high G inverted maneuvers.  A consideration is the retract installation often will have to be modified.



Main Gear Oleos – On the full scale Mustang as the weight comes off the struts they extend a few inches.  The popular retracts can be modified to do this.  However the wheel wells then must be moved to the wing centerline to accommodate the longer strut, turning it into more than a simple modification.  Note the position of the wheel to the outer landing gear door on the ground and in the air 



Main Gear Geometry – The location and angles of the stock landing gear along with the wing structure not correct.  The landing gear legs should be further forward in the wing and should be raked forward 11° when down (with reference to the wing chord line) and raked aft when retracted.  Getting the geometry right would require mounting its pivot at a compound angle in the wing.   Moving them forward would require that the leg be cantilevered out from the retract mechanism toward the front of the wing which only worsens the all ready complex mounting needs.  It's a tough problem.



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