YT International Douglas Dauntless SBD-5

 

 

 

 

 

Click here for finished model slideshow

Click here to go to end of build thread

 

 

 

 

The YT International ARTF model out of the box is finished to represent a Dauntless SBD-5, number 45. (SBD-5 signifying Scout Bomber Douglas - design iteration 5).

This particular aircraft was a U.S. Navy Douglas SBD-5 Dauntless of bombing squadron VB-16 off the aircraft carrier USS Lexington (CV-16). VB-16 operated from Lexington during the period September 1943 - June 1944, and was for a time one of only two Dauntless squadrons assigned to Pacific fleet carriers. The squadron participated in the famous attack against the Japanese Fleet during the Battle of the Philippine Sea in June 1944.

USMC VB-16 consisted of 36 Douglas SBD-5 Dauntless operating from the Lexington. The aircraft carried the new tri-color national insignia with a red surround but this slowly began to be replaced by Insignia Blue. In November 1943 the U.S. Marines began their assault on the Gilbert Islands and the SBD-5's of VB-16 took part with some still wearing the red insignia surround.

Ok, enough of the history and on with the model build. As the general outlines, finish and markings of the model are surprisingly accurate for an ARTF, it's worth adding further scale details during the build. Research shows SBD-5/45 did indeed have the red surround to insignia so all OK there. The model is 1/7th scale and should provide a fair representation of the full size Dauntless when built. The kit arrived in a huge box, parts being well packed with no damage on first inspection. Quality of the parts is good, very solid construction but not overly heavy and the airbrushed 3 colour finish with main decals applied looks authentic and true to scale.

WING BUILD - Build starts with the wings, installing servos and linkages for ailerons, flaps and dive brakes. Aileron servos are mounted on hardwood beams (replacing the hard balsa ones provided!) epoxied to the underside of hatch covers. Cutouts are already made with hatch supports and the supplied hatches all fit well. Some of the hardware items are a bit utilitarian and while perfectly servicable, have been replaced for a more robust connection or scale appearance.

16th January 2011

 

 

Wing panels with left hand panel aileron linkage fitted.

   
     
 

Aileron linkage upgraded from M2 to M3 rod and clevises and smaller horn.

 

The lower flap and upper dive brake are both operated by a single servo with 2 pushrods. Not practical, see note below re change of plan.

     
 
 

First minor problem with kit. Each pushrod should connect to upper dive brake and lower flap with a ball joint assembly which had parts missing from this kit. By modifying the servo position so it was at 90° to the hinge line it was possible to make and fit 2 GF horns and use standard clevises, offset to avoid clashing. As the pushrods fit in different holes in the same servo arm the outer hole pushrod has more travel than the inner one. No problem, the full size Dauntless dive brakes have 37° up travel and the flaps have 42° down travel so connecting the upper hole pushrod (more travel) to the flap gives some scale differential. - Change of plan!! Upper dive brakes are now fixed since can't have dive brakes and flaps operating together. May add extra servos later for working dive brakes (separate from flaps).

     
First outer wing panel almost finished, ready for some scale detail
Scale detail and weathering started.
     

Model is being finished to represent an aircraft in active service, well worn and stained due to constant action during the battle of the Philippine Sea. Scale details are applied using templates cut from thin card and masking tape. Shapes and lines are drawn using a soft pencil then rubbed by finger to represent staining and weathering (no Hammerite here lads!). Landing light is from self adhesive alum foil. A thin spray of satin fuelproofer will be used to seal markings. Aileron horn will be painted to match aileron colour. Top surface weathering next then start on the right outer wing panel followed by the centre section.

     

13th February 2011 - centre wing panel fitted with flaps, retracts and wing mounting hardware. Tried to get replacement retract cylinders to convert to air up/spring down but these are not available for the YT Dauntless. Normally wouldn't bother but since the retract air tank will be fitted in the central underwing bomb a 'wheels up' landing could cause quite some damage. YT were very helpful, spent a while on a Sunday evening with their technical support guy (thanks Martin) discussing the issue. Although YT offered to look at a custom conversion decided to stick with air/air and make sure retract system is sound and well maintained (then keep my fingers crossed).

 
     
Wing centre panel with belly pan fitted and weathered a bit
Position where the central bomb (with retract air tank inside) will be fitted

20th February 2011 - Back on the fuselage, a 13mm (2 x 1/4") ply spacer was needed to position the engine to suit the cowl front face

At this point a bit of vandalism (sorry, surgery) was required to allow the wraparound silencer to fit in place. The Dremel soon opened the lower fuselage front up and part of the bulkhead was also removed.

To strengthen the bulkhead again a 6mm ply plate was epoxied horizontally between the bulkhead and the next fuselage former.

A 3mm ply back plate was epoxied in place then hard balsa side pieces were added to complete the silencer cavity ready for filling, sanding and painting when epoxy dries.

Silencer fits easily into the cavity with air spaces at sides and back. Got the domed prop nut from ElectricWingman at a very reasonable price (just over a fiver delivered). Just the right scale for the SBD-5 (and SBD-4) versions which didn't have a spinner like earlier versions.

 

A litho plate will be fitted to cover the cavity and the exhaust outlets cut down flush with fuselage shape.

     

5th March 2011 - More surgery! Top decking areas cut away to allow some cockpit scale detail to be added

Moulded fuselage seems sturdy enough to cope with 'non-standard' cut outs
Dummy radial engine made from unpainted ABS moulding from Vortex Vacforms
Added a few valve pushrods etc and painted - pity about the Walbro carb sticking out so far. Gap left for cooling air and manual access to choke lever.
Cut outs for fuselage 0.5 calibre MGs made and cowl weathering started.
Exhausts made up and fitted, not included in kit which would have been nice
     
Twin MGs made from ali tube and fitted and ready for action
   
 
The radio gear tray extends too far into the front cockpit area so..
..more surgery to cut out the servo mounting apertures..
..which are replaced by cyparis beams in the area between front and rear cockpit cavities
Servos for rudder, elevator and throttle installed with a new platform for radio gear
Original cockpit areas looked a bit bare so slash and burn time again!
Dashboard with printed instruments was cut away and a new scale panel made up from ply with acetate for glazing instruments (found on the Internet and printed out). Thin ply shroud made up and painted matt black.

Gun breeches made from balsa/dowel, painted and fitted in scale positions either side of panel

 
     

Canopy windshield fitted, rest of canopy sections will be parked in area between front and rear cockpits

Optical gunsight made and fitted. A few more basic cockpit details to be added for now then further detailing can be done later. Need to move on, summer is coming!
     
Rollover pylon from balsa and litho..
..painted and headrest fitted
13th April 2011, back on the build after a few weeks off due to bereavement
Retract air tank built inside the 1000lb bomb. Bomb was cut in half with a bandsaw, tank secured inside with foam then rejoined halves (Join is under the rearmost yellow band). Air line exits through a small hole in the bomb into the wing centre section.

Disappointed with performance of YT retracts using variable valve to slow down retract rate. Wheels up works fine, slow and scale like but on down cycle wheels drop fast to about 2/3rd travel then slowly continue till locked down. System tested 100% leak free, pistons cleaned and greased, heavy wheels replaced by lighter scale wheels but still no joy. Robart and Ultra precision UP8 variable valves tried with the same result. The UP8 works perfectly on the B-17 retracts both up and down. Looking for any suggestions if anyone has come across this before and found a solution, may try spring loading wheels in the up position but need to move on for now.

     

 

2nd August 2011 - back after another layoff, fitting the tail parts, linkages and closed loop cables. Quite a lot to be fitted into the tail cavity. Several holes in the bulkhead and elevators in the wrong location but easily sorted.

While working on the tail end decided to install a working retractable arrester hook with a servo used to retract the hook and a soft spring to lower when the servo returns. No parts included in the kit but easy to make the bits required.
Set of parts made from plastic tube, Paxolin (us auld gits use it!) and liteply
To avoid cutting the fuselage too much, 'keyhole surgery' was used with the crank and closed loop cables assembled and inserted through the cutout before the pivot housing and hook were fixed in place.

Quite congested in the tail cavity but managed to squeeze in linkages for rudder, elevators, steerable tail wheel and return spring for the arrester hook

Arrester hook extended (lowered)..
..and retracted.
..and lowered again, this is fun!

Probably more bother than it was worth but an interesting exercise. Landings will also be 'interesting' if the hook fails to retract during a flight!

Scale tailwheel fairing made up from balsa

Percy pilot and Gary gunner in the 'office' - JP latex pilots painted with acrylics, rear firing MG from balsa and dowel

Canopy sections cut away and secured with 2 csk screws each side
 

Displacement gear required on full size to ensure clearance (12" min specified) between bomb and prop when bomb released in a vertical dive. Non-working gear on model made from balsa/ply. Fixed since retract air tank is enclosed in bomb!

4th September 2011 - racks (balsa and ply) for 100lb bombs made up and fitted

May have overcooked the weathering just a bit! However, the SBD-5s did tough work in a harsh climate so the finish took a bit of a beating with most aircraft looking very weather worn and tatty.

9th October 2011 - a few more details added, fuel dot (petrol version)
Carrier deck restraint point/towing hook from litho
Aerial and mast made and fitted
Insulated connection point to take aerial into fuselage
Engine installed and plumbed in - on the last lap, yipee!!
Done!
   

28th October 2011 - After 9 months on and off the Dauntless build is complete. Mostly enjoyable and without too many problems. With a bit of extra scale details and weathering the kit can be made to represent a reasonable scale rendition of the full size. Since it took so long to build to completion a full recheck of all the key building stages will be done, linkages, fasteners, electronics etc. Finished weight will be around 16.5lbs.

As it's late in the year, test flights will be held off until Spring next year when hopefully the weather will be kinder.

Click here for finished model slideshow

 
 

 

Wingspan - 72 "

Recommended engine 108 2S, 120 4S or 26cc petrol

Power - Evolution 26cc petrol

Radio - Spektrum DX8 2.4

Elevator, rudder servos (2) - Hitec HS-645MG

Aileron servos (2) - Hitec HS-325HB

Flap/dive brake servos - (3) Hitec HS-325HB

Retract servo - (1) Hitec HS-81

Operating tailhook servo - (1) Hitec HS-325

Throttle servo - (1) Hitec HS-325HB

Retracts - YT international supplied, air up/air down

Target flying weight 13 - 15lbs (5.9 - 6.8kg)

 

 

YT International website (Warbirds section)

YT International website (Home page)

 

 

 

 

 

 

Any queries e-mail billgl@lineone.net