BUMBLEBEE

With a large Mustang on his shopping list, Neil Diment changes tack and is seduced by the 3D capable Bushmaster from Legacy Aviation. Flying pictures by Al Morrow.

Let me cast your mind back to happier, more settled times... It’s August 2019 and I’m at the Nats with my mate, Billy. Two Scotsmen on the annual pilgrimage and we’ve headed into the Nexus Models tent so that I can check their price on the new Hangar 9 P-51 and look at some power options. Hanging from the ceiling Billy spots what appears to be a fairly large Turbo Beaver. 'Awf'y nice model that. Crackin’ scheme too!', he muses.

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When deploying the flaps, you'll need a down elevator mix of around 12 - 15%.

I can only agree, but it’s not what I’m here for. I check out the P-51; it too looks 'the business'. Desire surges within. It deserves a nice petrol four stroke, so I head to the desk and check the price on a Saito FG30. Billy is now deep in discussion with Paul about the Turbo Beaver. I offer my services as interpreter...

BUSHMASTER
It transpires it’s a 'Bushmaster' made by Legacy Aviation, a division of Extreme Flight. A bell rings between my ears - this company makes really high-quality 3D aerobatic machines. My own interest is awoken. It comes in three sizes: 65 inch, 84 inch and a whopping 120 inch wingspan.

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A 6S pack allows the big model to be hauled around in an impressive fashion.

The one suspended above is 84 inch span and flies on a 6S LiPo. My 5000 mAh packs are at the heavier end of the recommend batteries but will do the job. Paul confirms it can fly a wide envelope and a float kit is available. Billy is sold on it. We check Paul has a few of them with him and retire for a nosebag, a 'wee swally' and a discussion. The next day we both bought one!

I decided against the P-51 as I already have a couple of warbirds close to that size. The question I had to ask was, 'Which one will I fly the most?' It has to be said a model with big tundra wheels and the ability to swap them for floats without drama will bring more flying opportunities in Western Scotland.

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On the bench. You'll probably need a bigger board for this one!

A quick squiz on YouTube confirmed the model's abilities in more talented hands than mine, but given that I love flying indoor 3D I thought it would help me translate some of that to the great outdoors and help advance my flying some more.

YELLOW & BLACK
When you saw the article title and looked at the pics you might have thought that I am merely referencing the yellow and black scheme? But no, I’m ashamed to say that the lockdowns have made me watch a lot more TV. And I’ve now seen a Transformers movie!

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A vast cave of lovely bits and lots of fresh air inside the strong fuselage structure.

Bumblebee is an innocent looking VW Beetle that transforms into a huge yellow robot with impressive capabilities. And now that I’ve been flying my Bushmaster for a while the comparison seems appropriate - this innocent, albeit not that scale looking 'Turbo Beaver' is capable of flying very gently, but it can also deliver some truly wild antics!

ASSEMBLY
The model comes in 'traditional' ARTF format. The box is well packed and the major sections are nicely separated from each other. You get what you’re paying for here as Extreme Flight also include a padded wing bag with handy pockets for the substantial wing tube and supports.

Unpacking all the parts leaves a pleasing impression of quality and attention to detail. This is certainly not a cheap model but I’m still left wondering how the company produces components to this level of quality for the price. It really is exceptional. All components are beautifully made and covered. There's no need for the iron at all and the structures are very light, yet very strong.

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My fold-down work bench was supplemented by a ply panel on trestles.

The manual is detailed, with instructions and photos of matching clarity. Each step is logically thought out so there’s no benefit in altering the order they are tackled in. The hardware for each step is individually bagged and clearly labelled. Again, all of this impresses and inspires confidence.

For this build I decided to make life a bit easier and stick to the recommended motor. Captive nuts are pre-installed and the Torque Revolution 4016T/500 Mk2 has a good reputation, so I ordered that from Nexus. They recommended the Hobbywing Platinum 100A ESC rather than the 80-amp Airboss that the manual mentions, along with six Hitec HS225MG servos. If you intend to wring the model’s neck with continual 3D flying then maybe you should consider a higher spec servo, but so far the Hitecs have done me proud for my mixture of tentative 3D, energetic aerobatics and general flying.

POINTS TO NOTE
I’m not going to wax lyrical on the build, but I should mention the following. Even in its mid-range size of 84-inch span this is a pretty big aeroplane and whilst a lot of the assembly can be accomplished on a standard large workshop bench attaching the elevators to the fuselage requires some extra room. These need to be glued into a pre-cut slot hiding under the covering. This was new to me as all my previous builds have had two-piece elevators.

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Those big wheels can shift an impressive amount of water.

The manual stresses the need to measure between known points on the wings and the elevators on each side, ensuring all is straight, and that the measurements are identical before committing with glue. If you subscribe to the 'get all the hinges epoxied in early' method and haven’t read the manual thoroughly first, you will have a profound 'DOH!' moment when you reach this stage as the hinges are only epoxied in once the front and rear sections of the elevator have been individually slid into the slot.

This was also my first pull-pull rudder, with the tailwheel slaved to it via a solid link. Both these stages induced some cursing but thankfully I got through them okay. Otherwise, it was plain sailing - job done!

MAIDEN TIME
As you can see this is a decent sized model. Transport is made easier by the two-piece wing and my estate car swallows it easily. I reckon she’d fit in a medium sized hatch but do take some measurements. I set the model up using the recommended control deflections in the manual. Based on my experience, following them and taking off on low rates for the maiden flight is a very good idea!

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It won't be long until the optional float kit is needed!

On the higher rate setting the elevator imparts a somewhat lively performance and those without 3D experience will struggle. Having spent a few winters flying indoor 3D, I opted to levitate into the wide blue yonder using the high end of the suggested deflections. This was absolutely fine on all the other control surfaces, but with the elevator on high rate the first take off did induce a certain 'puckering'! Once I’d got used to the extreme sensitivity on the elevator over two or three circuits, I lined her up for a twitchy landing and reduced elevator travel by 30% and added a smidge more expo. Aha, much better! She now flew comfortably, and I started to enjoy it a lot more.

Wow, what a machine! A mate had questioned whether the motor would be up to the job and whether a plane this size could fly authoritatively on six cells. My answer is a resounding 'yes', although with a couple of caveats:

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Extreme Flight’s Bushmaster is way more capable than a first glance would suggest.

My 50 - 90C Admiral batteries deliver a good punch. Also, EF suggest fitting a beech 16 x 7 or 16 x 8 prop. I fitted a 16 x 7 Xoar and I’m going to swap it for the 16 x 8 before practicing more prop hangs and taking on torque rolls. More on this shortly...

But for general flying and ambitious aerobatics there is more than enough oomph on the 16 x 7 and the plane is capable of some serious hooliganry. Rolling circles, inverted circuits, effortless square loops and, thanks to all that drag, touch ’n’ goes off a half-Cuban. In all but true 3D I have yet to find its limits. The CG specified in the manual is spot-on and with that achieved the plane is completely neutral when inverted and those big slab sides keep her steady in knife edge. There’s no shortage of rudder authority so you can use that to pull her vertically away from knife edge.

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Flying again. Can you spot the repairs?

The manual mentions setting the flaps up using a program mix and using them as additional ailerons. When using them as flaps there is a need for a down elevator mix of 12 - 15%. I haven’t tried using them as extensions to the ailerons yet, so whilst the roll rate is swift and crisp enough for normal aerobatics, you’ll definitely want to set that up for torque rolling in the prop hang and have all that elevator movement back for 3D too.

So now, at least 50 odd sorties on from the maiden, I’m feeling WAY more confident and I'm pushing the envelope ever further. I’ve not yet brought her in low right in front of me and flicked into a prop hang with the tail inches off the deck yet. But, at a more conservative height, I’ve slowed her down in the vertical to the point of literally hanging the plane, then deliberately tail sliding her a few feet before applying full power and flying out vertically.

Then came a day, with the wind blowing at around 15 - 20 mph, that I foolishly tried this again. It was not really the weather for it but, hey, I had an audience...

MORE PROP, VICAR?
I duly hung the Bushmaster up, but too high (yep, the wind is stronger up there!) and too far out. I throttled down a bit and my Bumblebee began to slide downwards. I tried to get her to fall nose first into wind and recover from there, but I was now approaching fare paying passenger status as she drifted, sinking like a stone, rather quickly downwind, and she fell out really awkwardly, with the tail of the aircraft now pointing upward into wind. Full power, full up elevator and the nose started to rise, but not quickly enough - this was now a damage limitation exercise - so I cut the power and kept that stick all the way back...

We’ve all felt that sickening feeling as a gentle 'crump' audibly confirms what our eyes have just told us. A mate accompanied me on the walk of shame to examine the crash scene; he's a way more experienced flyer and so predicted a more favourable outcome. But I am mentally preparing to ask if anyone’s got a bin bag and listening to the chorus of 'if onlys' now chanting between my ears; if only I hadn’t attempted that manoeuvre on such a windy day; if only the ground had the common decency to be nine inches lower; if only I wasn’t such an idiot... You know the drill!

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I found my own limits well before reaching the model’s!

But Simon’s experienced eye called it accurately and the gear had torn out quite cleanly. Unfortunately, one of those big wheels had punched a hole in the fuselage, the elevator had popped clean out of its slot and that lovely Xoar prop was 'gubbed'. But it had done its secondary job, selflessly sacrificing itself for the greater good of the motor, its mount and the box, which all still seemed to be solidly connected. There was no damage at all to the wings and even the spinner was fine. My sinking feeling floated slowly back to the surface thanks to the life jacket of a repairable aircraft. It could’ve been a lot worse, so lessons learned...

Once I had got her home the model's smart design and use of quality materials revealed their benefit. The wheel hole was dealt with by pushing it all back in and wicking in thin cyano. On close inspection a few cracks were obvious in some of the fuselage frames, but most just need a bit of thin cyano wicked into the joins once they had been correctly aligned. A couple were bad enough to need a ply brace on each side of the frame.

Remounting the tail was easy; it all lined and measured up true so after I’d checked it many times thin cyano was wicked in. I know there are health concerns with cyano but its use here really brought benefits in the crash - I can only wonder what carnage would’ve resulted if the tail feathers were epoxied in...?

BACK TO THE SKIES
I was a bit worried about the 're-maiden' of this plane. How would my repairs hold up? Would she still fly acceptably?

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Bushmaster is a winter hack that you'll probably want to fly all year round.

I needn’t have worried. She still tracks straight and true and I’ve gradually pushed the envelope again, but I won’t be prop hanging and attempting torque rolls until I’ve sorted out the program mix and have it on a '3D mode' switch - and fitted a 16 x 8 prop!

Would I recommend this plane? Yes, unreservedly, especially if you want an aeroplane that 'transforms' from a big pussycat into an absolute animal, depending on how you set the throws and approach your flying. It's a large scale, float capable winter hack that you’ll still want to fly all summer.

If you only have room in your life for one model that can be almost any aeroplane that you want it to be then, Ladies and Gentlemen, I give you the Bumblebee. But not this one. It’s mine, I love it and I’m keeping it!

DATAFILE
Name: Bushmaster 84
Model Type: High wing sports utility (with hidden talents)
Manufactured By: Extreme Flight (Legacy Aviation Division)
RRP: £439.99 (may be subject to change)
Wingspan: 84 ins (2136 mm)
Fuselage Length: 64 ins (1626 mm)
Wing Area: 800 sq.in.
All-Up Weight: 8.5lbs (3.86 kg)
Wing Loading: 24.5 oz./sq. ft.
Power System: Torque 4016T/500 Mk2, Hobbywing Platinum 100A ESC, Xoar 16 x 7 prop
Battery: 6S 3300-5000 mAh LiPo
Functions: Rudder, Ailerons, Elevators & Flaps

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