40B – Landing Gear & Engine Mount

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Time to dust off the engine mount!

There were a few jobs to complete on it before mounting it on the fuselage …


Last Jobs before Mounting on Fuselage

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Machine Drilling nutplate attachment holes.


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Riveting nutplates. These are used to fasten P-Clips for the brake lines.


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Filing off the powder coat on a few of the attachments to ensure a good electrical contact with the fuselage.

The manual gets you to ream the attachment holes, but mine really only needed removal of the excess powder coat.


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The AN823-4D Elbows for the brake lines need to be attached before the engine mount is fitted. It would be hard to get access afterwards.


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Top Tip … Easily missed this one, since it isn’t mentioned until Section 48-04, Exhaust System!

Unless you have spotted this earlier, two pop rivets need to be removed from the Right Vent Assembly to allow a blanking plate to be attached.

This is MUCH easier without the engine mount in place : )

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Landing Gear Legs

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I decided to fit the gear legs prior to attaching the engine mount to the fuselage.

My helper Tim organised a couple of drift pins as specified in the manual. These will also be used later to help with aligning the wing attachment bolts.

Once the axles are aligned using the pin they are clamped firmly …


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… and then reamed to open up an under-sized hole.

We found it possible to double check the hole alignment visually prior to reaming … peeping through the hole you can see if the under-sized hole is perfectly concentric.

After removing stray powder coat the legs fitted easily into the engine mount, and a similar process is used to ream their attachment holes.


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Here’s the fuselage up on trestles so that the rotisserie could be removed ready for attaching the engine mount.

Tim & I managed to lift the fuselage by the wing spar, and Coral helped out positioning the trestles.


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It didn’t take long to attach the engine mount.

A long socket extension helps with torquing up the bolts.


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The legs are supported top and bottom of the mounting tubes, which need to be greased.

We decided to smear grease throughout the whole tube for corrosion protection.

We also sprayed LP3 Oil into the legs themselves.


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Legs on!


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The axles have a bead of silicone around the joint to prevent water ingress.

The bolt washers also have silicone underneath prior to torquing the attachment bolts.


Aligning Axles

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Checking the axle alignment involves stretching a thread between two blocks mounted on the axles parallel to the “axle flat”.

Any gap between the thread and block surfacee has to be within 0-1.0 mm, which is 0 to 0.7º toe out.

I was hoping that the care we took reaming the legs would mean no correction was required, but as you can see, the left axle was just out of tolerance.


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Shims are not provided in the kit, but various sizes are available to order from the Van’s Aircraft Accessories Catalog … U-00013A (0.75°) and/or U-00013B (0.5°) Axle Shims.

I used a 0.75º shim for the left axle which resulted in 0º toe.

Actually, when the shims arrived I realised they were made by Grove Aircraft … and they also supply a 0.25º shim not mentioned in the Vans manual.


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The right leg needed a 0.5º shim to give 0º toe.

I had forgotten to remove the Van’s axles from the kit order once we’d decided to use Beringer Brakes, but actually they proved useful for this process. The Vans ones are parallel, enabling the 3 inch block to be parallel to the axle flat.


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The Beringer Brake Axles which we’re installing have a tapered axle, which would have made the alignment process harder.


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The tailwheel spring installation went easily.

Again the attachment hole has to be reamed … Vans mention clamping the spring in position once a drift pin has been used to align the holes, but our spring was held firmly enough in the tube so that a clamp wasn’t needed.

As you can see, I fitted the JDAir Yoke with a lightweight tailwheel rather than the Vans stock tailwheel.

The geometry of the Fork allows for better ground clearance … pretty essential for a lot of the grass strips in the UK.


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G-STRV has landed!

We felt a milestone had been reached seeing her sitting happily on her own wheels!

Happy Dance : )


 

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