Jerry Bates 1/5th Hellcat

[Nick Somerville]

 

My next build on 6 beautifully drawn sheets based on Bentley drawings ( so should be accurate). I had planned a 1/5th Bearcat from the same designer but opted for the lighter wing loading of the Hellcat as there is an example at the nearby Yeovilton Air Museum. At 96” it’s a big span but I can just fit it in my Campervan if I build it as a one piece wing. The plan details three parts but one saves weight. Folding? No way!

 

A laser-cut parts set and my list of additional strip/sheet/ply has been ordered Slec and should be with me shortly. Slec have taken on Belair, which is a good thing imo as I have always enjoyed great service from them.

 

In the meantime I have fabricated the elevator and rudder torque links and horns. The plan suggests a servo for each elevator half but personally I don’t see the need on a warbird below 20kg. There are plenty of powerful high quality servos to choose from and flying a warbird in a scale manner, including scale aeros, barely taxes the elevator. That said I have upped the wire to 4mm and have silver soldered twin horns either side of the elevator ball link to maximise the joint strength. Elevator will have a carbon pushrod and the rudder internal closed loop. The support hinge parts are three layers of 3mm epoxy board glued and barbed for adhesion when gluing.

Engine will be a Saito FG R90 . If anyone has one sitting on a shelf with no plans to use one please let me know. I know they make great ornaments but ….
Retracts Robart pneumatic. Wheels are tricky as they need to be fairy narrow. 5 1/2”. Tbc. Cowl and canopy will come from Fighteraces in due course.

[Nick Somerville]

 

Stab almost complete. Sheeted in 3/32 instead of the 1/8th specified, as I really want to keep the tail end as light as possible. The plan specifies an American hinge system unavailable here, so have opted for the largest sized Robart hinges. As the pivot is 12mm behind the rear spar, brass tubing has been blocked in place and protrudes behind for added support.

 

 

Here the tips have been glued in place and await shaping. At over 1m span I realise that avoiding hangar rash when transporting the model is likely to be an issue. To mitigate against leading edge dings a 2mm carbon rod has been let in prior to shaping. Actually made a good centre line to sand to as a bonus. Tip blocks have 1/64 ply cores for the same reason. 
 

There are a pair of the Robart hinges on each side but the inner hinge points are integral to the elevator torque rod as shown  on my first post.

 

[andrew exton]

watching with interest might even encourage me to get mine out the shed & try  and carry on  with it

 

andy

[Nick Somerville]

 

Here we have the main frame of the elevators. Still the outer hinge blocking to add. A few ribs have been moved from the plan position to match the Bentley drawings I have. At this stage it feels heavy and I shall be sanding away more of the ply 1/32nd core. 
 

As it was raining I visited The Fleet Air Arm Museum yesterday to get some photographs of the Hellcat in Hangar 3. Took me a while as I was distracted once again be the quite amazing Corsair they have in the same hangar. Off topic but worth adding a couple of photos.

 

Anyway back to the Hellcat, it was a timely visit as the shaping of the elevator leading edge is next and without the visit I would have got it wrong. 
 

 

This shows how the rounded leading edge transitions to a v shape at the start of the tip. This v continues around to the trailing edge. I would have just rounded it so good to know.

Edited September 1, 2023 by Nick Somerville

[Nick Somerville]

 

 

Stab and elevators now completed. The shroud at the t/e of the stab is let in G10. The elevators are about 40grams heavier than the stab despite every  effort to sand as much of the 1/32 ply core away. I will fabricate the trim tabs after covering the tailplane.  Fin and rudder next. 

[Chris Freeman 3]

Very Nice Nick, the Hellcat is an interesting aircraft that makes a good model. I managed to get a half built Byron kit that needs to be finished. Too many projects and not enough time.

[Nick Somerville]

Some progress due to the autumnal weather.

 Fin ready for other skin glueing in place. I added the /8th spars and the diagonals to increase rigidity. The skins are .4mm as opposed to the .8mm specified. This saved a fair few precious grams.  L/E and tip block to add.

 

 

.8mm ply core for the rudder. Block backing to the front post for the Robart pin hinges and the actuating torque rod and horn  made earlier firmly blocked in too.

[david tilbury]

coming on really well Nick.....:-)

 

Nice work!

[richard dalgleish]

For inspirationMy 1/6 scale Bates Hellcat. 80" span, flies like a trainer.

Edited September 29, 2023 by richard dalgleish

[Nick Somerville]

Looks great Richard. What’s  hauling it around and which retracts?

[richard dalgleish]

23 hours ago, Nick Somerville said:

Looks great Richard. What’s  hauling it around and which retracts?

Zenoah 45 and Sierra retracts. 

[Nick Somerville]

With the tail parts finished a while ago I was unable to progress due to not having either the retracts or an engine. Having now settled on the engine choice (Saito FG 90 R3), currently on order,  dimensions were sourced from the web and the firewall prepared for mounting it. 37mm was cut back from the front of the fuselage/engine box so that the Saito can be mounted on 40mm stand offs. This means that the servos and links to the carburettor can be positioned on the cowl side of the engine box rather than buried inside potentially fouling the fuel tank. A further benefit is plenty of air circulation around the ring muffler.

 

 

The hole is for the carburettor Venturi to poke through where it can draw cooler air. 
 

 

The supplied engine mounting plate was 1/4 birch ply which is barely enough to hammer the T nuts in from behind without weakening it. A layer of carbon cloth and a further 1/8th of light ply was epoxied together and heavily clamped. Not much extra weight, much more strength and the light ply at the rear ideal to bash the t nuts into. Once glued in, thick bamboo skewers were glued into pre drilled holes to further strengthen the joint and 1/2” triangle balsa all around on the inside.  I will leave any triangular support at the front until I have servos, batteries and ignition organised.

 

After marking the former positions thin strips of 3/32 were glued either side prior to gluing the formers. Simplifies keeping everything straight and greatly increases joint strength

 

 

Not entirely sure why several of the former protrude below the wing saddle line on the fuselage box but I am sure it will become apparent. The building board is from a damaged length of melamine shelving purchased for a few quid at a local hardware store. I have bolted it to some aluminium section to keep it true and it will aid turning the assembly so I don’t have to lean over when planking the far aide.. my workshop is very small with no space for a central table.

[Nick Somerville]

Short lengths of balsa have been stuck down onto the melamine with cyano to accurately jig the base of the rear formers in place. The longerons will keep them vertical once added. 
 

 

[Nick Somerville]

 

Air reservoir located as far forward as possible. Not entirely sure its a good idea to have it somewhere where it can’t be replaced but I figure a failure is pretty unlikely. I have chosen a scale hatch position to locate the Powerbox Sensor Switch and the twin remote charge sockets for the main batteries. The air fill valve will also fit inside. The hatch on the full size is top hinged but have made a sturdy bottom hinge that will only show as a panel line. I will add a dummy hinge to the top of the litho hatch door that will also help to pry it open against magnets.

 

With all the stringers in place time for some sheeting next.

[Mike Chantler]

On 13/09/2023 at 16:36, Nick Somerville said:

 

 

Stab and elevators now completed. The shroud at the t/e of the stab is let in G10. The elevators are about 40grams heavier than the stab despite every  effort to sand as much of the 1/32 ply core away. I will fabricate the trim tabs after covering the tailplane.  Fin and rudder next. 

Lovely build. Curious as to what the G10 is?

[Nick Somerville]

Thanks Mile. G 10 is glass fibre sheet. The stuff I have is about .6mm thick. I purchased a roll of about 2X3m off BMFA classifieds a few years back and use it a lot. It’s a stronger alternative to 1/64th birch ply (a favourite material) and only a tiny bit heavier. Cuts easily with scissors or by scoring and snapping. It isn’t suitable for compound curves but otherwise has a myriad of uses.

[Mike Chantler]

Nice 🙂

 

[Nick Somerville]

Getting some sheeting in place. Using a mixture if thick cyano and aliphatic glues. Turning the board after adding each piece as sheeting one side first could be a recipe some longitudinal distortion.
 

 

 

 

[Tim Flyer]

A really nice build Nick👍

[Nick Somerville]

Due to the way the control horns sit in such a tight space for the rudder and elevators I need to complete the covering, priming and hingeing of these parts early in the build. This includes glassing the stab and fin so some 48grm cloth on order from my usual eBay supplier.

 

Rudder and elevators covered in natural Oratex and freshly simulated stitching trailed lines from a tiny glue bottle and nozzle filled with pva.
 

 

Once dried back the pinking strips, from Mick Reeves, are added. 
 

 

Here the full size.

 

[Nick Somerville]

Finally back in the workshop after an enforced break due to a long overdue bathroom renovation.  Although I am still waiting after two months for my retracts to be manufactured by Robart I have been kindly lent a set, which means I can get on with the wings. 

A 500mm x 50mm aluminium tube and phenolic sleeve  are being employed for a two piece wing. The belly pan will need to be made removable for attaching them but I think prefer this to a three piece wing.

 

I am at the stage where I am ready to sheet the top of the centre section. Once done I can frame up the rest of the wing on the board with the centre jigged up for the dihedral.

[Nick Somerville]

 

The centre section was jigged up and the outer panels were framed up and top sheeted one at a time. I do enjoy sheeting! The ailerons will be built up separately along with the flaps areas. There is a large overhang where the flaps  separate and are hinged so I am sheeting this area separately with a carbon balsa laminate for rigidity.

 

[Nick Somerville]

I have been a bit confused (usual) regards the flap construction and although the upper shroud is now in place I have made a start on the ailerons whilst the brain fathoms the flaps.

 

Here’s one of them. Pretty straightforward but as the full size had fabric covered ailerons it’s a bit of a work around. Sheet underside for rigidity and a laminated trailing edge with carbon tow inset and a 1cms strip of G10 below. Nice and stiff.  I can simulate the rib stitching and pinking strips on both sides once covered, though the upper side will be more realistic. Still to add are the reinforcements for the hinges. 

 

Below are the upper and lower wing areas with the flap shrouds. As previously mentioned this is a G10/balsa/carbon laminate to cope with the large overhang.
 

 

 

[Andrew Calcutt]

Superb work,that is a big project but will be worth it

[Nick Somerville]

 

 

Aileron hinges in the lasercut parts kit were ply and not durable enough, so 2mm glass fibre sheet has been employed.  After marking  out a dremel was used to drill around the shapes few drilling and then they were sanded and filed to shape. One if those tasks that you inky want to do once in a while!