Tailhook Topics

by Tommy H. Thomason

Wednesday, September 21, 2016

Kitty Hawk 1/48 F2H-2/2P Banshee

This is a work in progress. What is here so far is based on the assembled kit on display in August at the U.S. IPMS Nationals and photos of the production sprues and instructions. However, I have just received a kit from Kitty Hawk that allows me to examine one in detail.

There's a good summary of what the kit includes here: http://www.cybermodeler.com/hobby/kits/kh/kit_kh_80131.shtml

The first impression is very, very favorable. There are many detail features like a complete gun bay for the F2H-2 and a camera bay for the F2H-2P, the seldom-seen speed brakes, and options for extended flaps and folded wings. Assembly and fit are facilitated by the presence of small tabs and posts and corresponding slots/ledges and holes. For example, if you choose to close the gun bay doors, which have a neat representation of the piano hinge at the top edge, there is a lip on the other three sides that sits on a ledge in the opening of the nose to minimize fit problems.
I held back initially on some of my observations about the assembled kit and photographs of sprues when they fell into one of three categories: 1) the problem would be fixed before production, 2) distortion due to lens effects, and 3) the builder was working without instructions or familiarity with the subject and therefore had to guess where some parts went. (In the latter category, for example, the assembled F2H-2 had the right-hand ammo cans on the left side of the nose).

Some of the problems already noted on modeling websites are exaggerated by camera effects. Yes, the model is a little sway backed but not as bad as photos would have it and it can be reduced by some shimming. The overall fuselage height and length are to scale: the kit is not tubby. The canopy ledge is not too steep; it is as close to the right angle as I can measure. The engine inlet looks a lot better than it does in the picture although it is a bit too deep.

There are some things that could be fixed or not. Few will notice that the nose landing gear yoke is too long or the vertical tail is a little oversized in height and chord. However, there is that excessive upward bulge in the engine nacelle. It is by no means eggplane-like in appearance, but if you think of the Banshee as being sleek as I do, it is distracting. I'm in the process of determining if there is a reasonably easy fix to minimize it.

In the meantime...

(Note that the box art canopy is based on the short XF2H-1 sliding section and the windscreen with the straight-sided windscreen.)

This appears to be an excellent basis for an F2H-2 and -2P but could benefit from some corrections and additions. Some have questioned the fuselage length versus height from the pictures but the length of the assembled kit that I handled was correct and the height of the fuselage looks about right. There is a question about the shape of the engine nacelles.

The kit does not include the fighter's gunsight, only the -2P view port. The gun sight was a Mk 8 Mod 0 that set in a trough in the glare shield similar to the photo view port's.
This is one of several pictures of this gunsight on the web site, http://www.aircraft-gunsights.com/usn-collection/

 Another omission is some of the detail stuff behind the headrest.

I'm not sure about the size and angle of the armor plate behind the ejection seat. It's present in the illustration above but doesn't seem very prominent in pictures, if there at all.

Note the fixed links on each side of the forward lower edge of the canopy. They have rollers on the bottom that slid back in a trough that angled upward as it went aft so the canopy bow rose to clear the pilot's head.

Nose landing gear improvements/corrections:

The wing flaps need some work to be accurate. The two inboard flaps should not have mostly parallel leading and trailing edges; the trailing edge tapers forward so that the flaps are parallel to the ground when extended. The outboard flap should incorporate the trailing edge of the wing but not the entire upper surface.
Although the two inboard flaps (shown in the color inset above) are separate structures, they are actually bolted together to form one surface and are roughly parallel to the ground when extended.


Another view of the wing upper surface included on the outboard flap trailing edge. Note the corresponding "cutout" in the upper wing trailing edge.

The top of the engine "nacelles" appears to be bulged upward and the intakes, not raked enough when
viewed from the side.
Note also the position of the nose wheel relative to the wheel well on the assembled kit.

The kit has the two most inboard pylons staggered longitudinally. It would appear that they were in fact not staggered. Unfortunately, I don't have station data for them.

Only the two inner-most pylons could be loaded with 500-lb bombs and if they were, the adjacent most-inboard pylons could not be used. All four of the most inboard pylons could be loaded with 250-lb bombs; the pylons on the outboard wing panels could only be loaded with 100-lb bombs. All eight pylons could be loaded with rockets.
Note that the tip tank is not mounted square to the wing tip but is notably angled downward.

The following illustration (note the correction to the size of the box from the original post) provides the lines-drawing information to check the engine nacelle size and shape if you are so inclined. Note that the cut of the nacelle is slightly outboard of the fuselage and therefore does not include all of the interface of the nacelle with the fuselage going aft:

An F2H-modeling post from several years ago: http://tailspintopics.blogspot.com/2009/12/f2h-banshee-modeling-notes.html

Two recommended references:
http://www.ginterbooks.com/NAVAL/NF73.htm


















http://www.milavnarc.com/f2h_banshee_in_detail_scale_part_1_digital_book.html


















More later...

Monday, September 12, 2016

Things Under Wings - Post-War External Tanks

Early on, AD-5s were seen with external tanks that were clearly not the so-called high-speed ones developed by Douglas in conjunction with the Mk 8X bomb shapes*. This is an example.

I haven't been able to find any data of these tanks other than examples, no two of which agreed in dimensions, of 150-gallon tank drawings on Standard Aircraft Characteristics for some airplanes. I was also initially confused by conflicting results from scaling photographs until I realized that there were probably two different but similarly shaped variants, a 150-gallon tank and one with a 300-gallon capacity. The result:
 I'd appreciate it if anyone can provide any information for these tanks, even just dimensions.

 *http://tailspintopics.blogspot.com/2011/07/douglas-low-drag-external-fuel-tanks.html

Thursday, September 8, 2016

Skale Wings 1/72 Douglas AD-5W Skyraider

11 September 2016 Update: I've been adding to this post over the past few days but I am pretty close to declaring victory. Note that this is not a build review; all I've done so far is dry fit the radome and the fuselage halves. There is a build review started HERE. It is in Russian but there are lots of pictures and Google Translate deciphers most of it.

The kit that Skale Wings graciously sent me well over a month ago finally arrived from Ukraine today (I had despaired and finally ordered one from Hannants last week, which should also be here soon).

The excellent news is that the kit is injection molded, not resin, and also not simply a mashup of the undersized Monogram AD-5 fuselage and the Hasegawa wing/cowling, although it is clearly based on (but not simply copies of, e.g. the main landing gear is a bit more detailed than Hasegawa's) those kits. The fuselage size is in the ball park and the kit includes a better-than-average instruction sheet, what looks like a good decal sheet with four option, vinyl masks for the canopy, and engraved panel lines on well-molded parts (there is some flash and cleanup of mating surfaces is required but the sprues and runners are petite) : a very good first effort from Skale Wings.

There are some hiccups, like the shape of the upper part of the front of the radome (the radome is a very, very difficult shape to define: I've tried to do it a few times without becoming satisfied although I think I'm close now), the erroneous presence of the narrow-body's catapult hooks located in the wings (and the wrong forward-facing landing gear doors), a not quite right aft canopy, two seats in the aft cabin rather than one, the external tanks mounted too far aft—but all-in-all, a far better starting point than trying to enlarge the Monogram fuselage and come up with a radome, not to mention that everything I've noted above, and detailed below, is either fixable without undue effort or can be ignored.

The Cockpit

Beginning with the instrument panel, the right side was basically a duplicate of the APS-20B Indicator in the cabin as shown in this sketch, only with a hood added for viewing the radar screen.

This is the pilot's instrument panel. Note the curved protuberance at the bottom and the center pedestal under that.

The AD-5 seat was an elegantly shaped aluminum shell.

The headrest and back were covered with a cloth-covered cushion. A parachute and seat cushion were located in the bucket.
The kit provides control sticks for both the left and right side of the cockpit but Navy AD-5s only had a stick on the left side.
The stick was on a pedestal that moved back and forth for pitch control. The kit stick (D2) might need more of pedestal.

None of the cabin detail provided will be seen since the opening between the cockpit and the cabin was closed off with a light-proof curtain. However, for completeness, there was only one crew seat back there, rather than the two provided in the kit, with the rest of the cabin filled with electronic gear.

The kit's radar operator's instrument panel resembles an AD-5N's rather than the AD-5W's shown here:
The Canopy

However, unless you go to the trouble of opening at least one of the aft hatches, any detail in the cabin will go unseen:
The canopy provided in the kit is pretty much a copy of the Monogram AD-5's "blue-room" version. The AD-5W aft canopy hatch and the section between the hatch and the sliding canopy were redesigned early on to be all metal, except for a small window (which could be blanked from the inside by a cover), to allow the radar operator to better view the radar scope. In the process, the hatch was reshaped to have a bulge over the operators head, with the fore-and-aft center section being unchanged.
One option to view the rear cabin is Falcon's vacuform canopy (Clear-Vax) set number 4. It includes an A-1E canopy that should fit this kit. You'd have to cut out the rear hatches and vacuform bulged ones, but that's no hill for a stepper...

Deleting AD-6 Features

Skale Wings unfortunately did not delete some of the AD-6 specific features on the underside of the wing (the lower wing half also includes the hole for the cannon barrels).
The oil cooler air outlets (the top two Xs) can be left alone on an AD-5W build since they are covered by the radome.

The catapult hooks moved to the main landing gear struts of the AD-5. Note that the forward-facing gear door was notably different than the AD-6's included in the kit since the AD-5 did not have the doors covering the wheel wells.
The oil cooler outlet was moved to the side of the fuselage just above the wing leading edge.
This is very faintly represented on the kit fuselage. Note that the door, which was hinged on its forward edge and opened outward like a cowl flap, does not extend as far aft as the trough it closes off. The door doesn't open very far, at least not that I've seen in photos and is usually closed tight on the ground (you need the oil temperature to be above a minimum value for takeoff).

Dive Brake Well

The AD-5 had only a single dive brake, the one under the fuselage. I knew that it had been deleted from the AD-5W but I only very recently learned that its well was not closed off as it had been on the AD-4W (to the extent possible, the basic AD-5 airframes were identical when they left Douglas).


For a bit more on the dive brake well, see http://tailspintopics.blogspot.com/2016/04/ad-5w-belly-detail.html

Dorsal Fin

The Skale Wing's representation of the intersection of the dorsal fin with the fuselage is a bit crude. Monogram's is much better and looks much more like this:
On the other hand, the Skale Wings kit  depicts the air inlet on the leading edge of the vertical fin and Monogram's does not. (Both omitted the orange and white running lights on the sides of the fin.)

Radome

The shape of the APS-20 radome is very difficult to pin down, at least to my satisfaction. I've spent a several hours off and on over the past few years trying to do so.  The Skale Wings version looks pretty good to me except for the excessive recurve at its upper front. This is how it should look (and where it is located relative to the lower intake; also note the radome intersection with the wing root just aft of the leading edge):

This is the kit's radome and my suggested correction (the fit with the fuselage isn't all that good anyway):

Drop Tanks

The kit comes with two 300-gallon drop tanks that appear to be accurate in size and shape. However, they are located too far aft on the pylon. It appears that the location of the tip of the 150-gallon tank was used to incorrectly position the tip of the 300-gallon tank:

In any event, most AD-5Ws are pictured with only one drop tank, invariably in that case on the right-hand side, almost always the smaller 150-gallon one, and sometimes the 150-gallon tank that predated the Douglas high-speed shape. The reason is that the AD-5W could loiter for over four hours on internal fuel alone, about three carrier cycles. Two 300-gallon external tanks gave it an endurance of 11 hours, which probably exceeded the radar's mean time between failures. As it happens, the Monogram AD-5 comes with 150-gallon drop tanks that are just slightly undersized but acceptable representations.

Decals

Color profiles and decals are provided for four different AD-5W/EA-1Es. Note that the LSO sight lines for angle of attack indication should only be on the left side of the vertical fin. The name of the Kearsarge is misspelled, but it doesn't appear on the AD-5W in the profile and the name is misspelled that way on the accompanying text of a photograph of it that is available on line.

On many (most?) AD-5Ws the national insignia on the underside of the wing is located well outboard like those on the attack-mission ADs, which was done to avoid the stores pylons on the outboard wings.
 (Also note the presence of the dive brake well.)

Radio Antennas, etc.
 There is a stall strip on the leading edge of both wings just outboard of the wing pylon.


My go-to references for configuration detail are Steve Ginter's Douglas AD/A-1 Skyraider Part One (Navy Fighters Number Ninety-Eight) and squadron/signal publications A-1 Skyraider Walk Around Number 27 by Ed Barthelmes and Richard S. Dann.

Monday, August 22, 2016

A4D Skyhawk, One More Time

4 September 2016 Update:

The A4D engine's tail pipe was centered within the aft end of the fuselage tail cone on supports, which allowed cooling air to flow between the tail pipe and the fuselage:

The original production aft fuselage ended at the lower point of the "sugar scoop'. For some reason, the tail cone was extended a bit farther aft for (or maybe during) A4D-5 production (the A4D-5 prototype modified from a -2N still had the original tail cone; A4D-2s and -2Ns subsequently received the modification at overhaul). At some point after that, possibly in conjunction with the installation of the P-408 engine, a constant-section lip was added, further extending the tail cone slightly. However, this lip was also seen eventually on A-4Bs and Cs by the late 1960s.
Informed comments and corrections are welcome.

I've spent some time reworking the length-comparison illustration that I did once upon a time.
However, it didn't change noticeably.

Questions have arisen about the size of the A4D stabilizer and width of the fuselage in various kits. This is a top view that I created from pretty good Douglas drawings and dimensional aero data for the wing and horizontal tail (root chord, tip chord, and span). Note that the interface of the horizontal stabilizer with the vertical fin is notional.
Some of the questions stem from comparison of kits with the Dana Bell's A-4E multi-view drawing in Detail & Scale Volume 32. It would appear that his fuselage is too wide and the horizontal tail slightly too large, among other errors. According to Dana, he didn't do the research for the drawing, only redrew (traced on mylar with rapidographs, the good old days) and added detail in accordance with the information that he was provided.

For a lot of other A-4 stuff, see https://tailspintopics.blogspot.com/2013/03/a4d-4-skyhawk-collector.html

Friday, July 22, 2016

Grumman F8F Gunsight

According to the F8F Pilots Handbook for all Bearcat types, "Early model day fighters were equipped with a Mk 8 Mod 6 (gunsight), while later models are equipped with a computing sight unit Mk 8 Mod 0".

The Mod 6 was a simple fixed reticle sight that projected deflection rings and cross hairs on the windscreen.  The Mod 0 was a gyroscopically controlled range-finding sight that provided lead; it projected cross hairs and ranging images on a reflector glass mounted on the gunsight itself.



I don't know that the change in the gunsight had anything to do with the change in the windscreen angle of the -2 (see http://tailspintopics.blogspot.com/2016/07/grumman-f8f-bearcat-windscreen.html) but it's possible that it was necessary to provide clearance between the Mod 0 sight and the center panel of the windscreen.

Dave Collier adds the following background:  Most of the F4U-4s that I worked on had Mk 8 Mod 6 Sight Heads. Unfortunately we had two aircraft which were equipped with the Gun Sight Mk 18 Mod 6 System which used a Sight Unit Mk 8 Mod 0 that was part of the Aircraft Fire Control system (AFCS) Mk 6 Mod 0. Because this system was still classified “Top Secret” in 1954-55 we had to post an armed guard on the planes whenever the flight line was not in operation. I did not enjoy the winter nights carrying a shotgun to protect the planes. In 1956 we received AD-5Ns which had Mk 20 Mod 4 sights. He also referred me to this interesting website: http://www.aircraft-gunsights.com/usn-sights/