Technical

Homebuilt wings

If you’ve ever thought about building your own aircraft, maybe now is the time to start! There’s a huge range of aircraft to pick from and modern kits have never been better…

Pilots can all agree that flying is an amazing experience, but imagine what it’s like to fly an aircraft
that you’ve built, which you’ve
personalised exactly how you want it? Thousands of pilots have done just this, and today’s modern kits and equipment make it easier than ever to build your own aircraft. 

In the UK, you can build your own aircraft in a number of different ways, but the most popular route is via the Light Aircraft Association (LAA), under the supervision of one of its UK-wide network of inspectors. There are around 200 approved designs you can choose from, though most new builders choose from around 30 of those, as they are the most current, supported types.

Permit Aircraft typically offer some of the best combinations of great handling and performance. There’s even an option for some specific types to be approved for IFR flight too.

Homebuilding is an excellent way to get the aircraft you want, to your personal specification, and to spread the costs over time, if you’re trying to keep to a budget. 

Plans or kit?

Only a handful of people build from plans, but it’s probably the cheapest route into homebuilding. There’s machines to cater for all requirements too, but don’t forget, if you plans-build, you’ll be responsible for sourcing all the materials and parts for your project. It’s a mighty task, but well within the realms of an organised builder.

For that reason, most builders opt for a kit aircraft, and today’s modern kits have evolved to be quite advanced in their presentation, with many designs having structures that self-jig if you follow the instructions correctly. There’s three types of kit, and you’ll typically hear them referred to as a ‘flat-pack’, which is the whole airframe supplied in component form. Then there’s the ‘quick-build’, which will see a partially constructed airframe, typically a fuselage tub and partially finished wings, delivered to the builder. Finally, there’s ‘fast-build’, which sees individual sub-assemblies, delivered mostly complete, with the bare minimum to do before inspection and closure of the structure. Some options include pre-covering and pre-painting. Opt for this level of kit, and you’ll  ‘just’ find yourself having to complete the instrument panel, install the engine and associated firewall-forward components – and fit the interior trim. 

While fast-build might sound too good to be true, it’s not. Francis Donaldson, Chief Engineer of the LAA explains. “We appreciate that many people don’t want to spend years in the workshop building their aircraft and want to see a quicker result. However, it’s a fine line because we have to preserve the 51% rule element, to qualify as Annex 2 under the EASA basic regulation and in concept, to ensure that the builder can meaningfully take responsibility for the major portion of the build, and importantly, to allow an LAA inspector to have a fair chance of inspecting the whole aircraft rather than having to rely on any formal inspections / quality control on the part of the kit supplier. That said, assembling such a kit can be done in relatively short time and given a reasonable degree of care and the supervising influence of an LAA inspector, the risks of expensive mistakes are minimal and the whole thing is a very pleasant creative experience.”

While many homebuilders tackle projects on their own, there’s no reason that you can’t team-up with friends to build. Think about how you’ll divide up the work and the shares in the aircraft, and make sure everyone understands the commitment. A good building partner will make the building experience more fun.

Space to build

There’s a clue in the word homebuilding… you’ll want to see what space you have around your home for a workshop. If you want the best chance of making fast and continual progress on your project, then make sure it is just a few steps from your everyday life.

I’ve seen photos of builders working on major portions of aircraft in one-bed flats, and I’ve known husband and wife teams decide that for a few years, building their project in their living room would guarantee better progress than having to step outside to go to the garage.

Any space you can free-up for building at home is good.

“I don’t need any more space…” said no homebuilder ever! So it’s about trying to find the biggest space you can. For the typical UK homebuilder, the space of choice will probably be a garage. A two-car garage will provide enough space in which to house a typical two-seat kit aircraft during the course of construction.

If you’ve only got a single-car garage, don’t worry, these are usually pretty useful for most two-seat designs, and while you may not initially have all the space required for some of the bigger rigging jobs that will occur later on in the project’s life, you’ll be surprised just how much you can achieve in the early stages of airframe construction. An empennage kit, wings and fuselage are all possible to build in stages in a single-car garage.

By the time the fuselage needs the engine fitting, many builders get creative and add temporary structures to their garages to create additional space. Yes, there will be some occasions when you’ll need to rig the basic airframe – we’re talking fitting both wings and maybe the empennage – but it’s usually only a short time that the airframe needs to assembled like this. You might find working just a ‘long day’ with it temporarily assembled will be enough, and for that, a cheap gazebo in the back garden or on the driveway is a good temporary solution.

If you’re not fortunate enough to have a spare garage, then a temporary wooden cabin in the garden can make an excellent workshop. No matter what space you end up with, make sure its clean, bright, has storage and workbench space. Crucially, it’s got to be a  comfortable place to spend time in all year-round, otherwise it can be more tempting to stay indoors on those very cold days, rather than pop out to the workshop!

Building with wood means assembling parts, which then glue together to make an airframe

What to build?

When it comes to selecting what aircraft you want to build, first of all you’ll need to decide on what type of flying you want to use it for. One, two or four seats, side-by-side or tandem seating? Just a fun-flying aircraft, or a serious tourer? VFR or IFR? Want to stay straight and level, or fly aerobatics once in a while? Your answers will help you refine your kit choices. It might even be that airframe component size figures in your decision making. If the type you choose has a 30ft span one-piece wing, have you got space to accommodate that?

If you’re left with a few to choose from, then take time to research each one. Is the design a mature one with the inevitable bugs ironed out of it? Does it have a comprehensive build manual? Is the company or UK agent behind it one that will still be around ‘X’ number years in the future when you need remain kits or parts? An excellent UK agent, or very supportive company can be hugely helpful in the course of a build project, and you’ll get a good feel for this by talking to builders already building these aircraft in the UK.

Material types

Your choice of which aircraft type to build will almost certainly be the deciding factor for which material you’ll be working with. Looking at popular homebuilt kits of the last 10 years, aluminium appears to be the choice of most builders. Aluminium has the advantage that once you’ve finished fitting the skins to the airframe structure, that’s your final finished surface and it needs no further preparation to be ready for flight. Of course, that also means that your skills with the rivet gun will be forever on display. Learning to rivet with a rivet gun and bucking bar isn’t hard, and you’ll find your skills get better, the more you build. A popular alternative to conventional solid rivets is blind-riveting, where the builder uses a tool to  mechanically pull specially made rivets from the outside of the structure. It’s easier and has less chance of errors, however pulled-rivets are more expensive. Don’t think that a metal aircraft will mean no you won’t have to deal with fibreglass though, as the material is used for the curved shapes of non-structural parts like cowlings and fairings.

Tube and fabric is a time-honoured, but effective, way to build an airframe. This is a KFA Safari

A number of kit aircraft have a steel-tube fuselage with wood or metal-structured wings that are then both covered in fabric. Complex operations like welding are completed at the factory, so you won’t need to learn how to weld.

Wood airframes use techniques that are roughly similar to metal aircraft, just that the parts are cut from strips of spruce and Douglas fir and sheets of plywood. The parts are then assembled using modern aerospace glues. For many aircraft builders, wood is a friendly material and quite forgiving of mistakes. Once a wooden airframe structure is complete, it’s either skinned in plywood, or covered in fabric, or a combination of the two.

There’s a number of options for fabric covering a homebuilt, including Ceconite, Poly-Fiber, Super Flite and Oratex. All are glued on and shrunk using an iron, but they vary in the way they are finished and painted, except for Oratex, which is pre-coloured.

Composite aircraft kits on sale today usually require bonding components together in the same way you might with an Airfix fit. This allows for often rapid progress in assembling the basic airframe, and the surfaces of the moulded components typically need very little finishing by the builder.

Composite kits do tend to be more costly though, and require very accurate control of temperature and humidity in the workshop to make sure the materials cure correctly. A more old-school composite method requires the covering of foam cores with glass cloth, which while simple, is labour-intensive to fill and sand to a fine surface finish ready for paint.

Whatever material you’ll be building with, it pays to be well trained in the basics. The LAA has a network of inspectors – you’ll need to arrange for one to oversee your project, they will be able to help you get started.

Composite kit aircraft are usually assembled from multiple premoulded parts

If you want to get a real flying start, the LAA also run a range of educational courses at locations around the UK for all the different construction methods. And remember, most of the popular homebuilt types have very active internet forums and these are an invaluable way to help you meet other builders.

Your material choice will also influence one other homebuilding factor, selection of the right tools. In my experience, spending a little extra to get the best tools you can afford right at the start will enhance your building experience, particularly as in some cases you’ll be using them for thousands of repeated operations. As a smart tool buyer once wrote, “The most expensive tools you can buy are the ones you buy twice.”

Getting some help

If you think you’d rather have a little more help, then some manufacturers offer builder assistance schemes. LAA’s Francis Donaldson again. “The LAA is happy to see amateur builders having the opportunity to carry out some or all of their build under supervision and instruction. It saves a lot of ‘thinking time’, and usually results in a better quality job. The important thing is that the amateur builder still does the actual work, and gains a full understanding of the educational value of the project and an in-depth understanding of their aircraft, just as if they had built the whole thing at home.”

Aluminium skins and formers are assembled to create an airframe structure, in this case, a Zenair fuselage

Making changes

It no surprise that making changes to a build can sometimes be the path to difficulties and delay. On this LAA’s Francis Donaldson has some wise words. “Beware of products on sale to amateur builders that may not be as proven as their advertisers would have you believe. Of course, the ability to experiment is part of the ethos of flying non-certified aircraft, but sellers unsurprisingly don’t stress that element when trying to persuade you to part with your hard-earned cash. Engines in particular are an area where it’s easy to be taken in by sellers claiming to have a tried and tested alternative to a Lycoming, Continental or a Rotax, sometimes at a temptingly lower price. Sadly, there’s a long history of underdeveloped or downright unsuitable engines being brought to market that just aren’t up to the job. Every new design of engine needs years in service to get the bugs out of it. Don’t become part of an extended research and development programme – an engine that goes silent all of a sudden might very well wreck your pride and joy.

“Finally, keep in mind that even if the powerplant, propeller or whatever modification works for you, a non-standard fit may have a marked negative effect on the resale value of your aeroplane. The kit supplier’s ongoing support is crucial too. They put a lot of effort in finding the optimum spec for their design, so don’t be surprised if they are less than sympathetic if you decide to go your own way and ignore their advice.”

Rotax-powered Zenair CH750 which shares seventh spot, alongside Van's RV-10, as one of the most popular homebuilt aircraft in the UK. See the table below.

“Stick to the instructions and resist the temptation to make modifications”

Get building!

It may sound obvious, but once your build is underway, try and do something towards it each day, no matter how small! Stick to the manufacturer’s instructions and resist the temptation to make modifications, as the LAA will require you to submit each one for approval. Save your creativity for designing and building the instrument panel. It’s by far the best place for any builder to easily put their individual ‘stamp’ on their personal machine.

Don’t worry too if at some point you think you’ve bitten more off than you can chew! Any project of this size might be daunting if considered as a whole – the analogy of trying to eat an elephant is often used – you’ll only manage it in little chunks!

Finishing will often creep up on you, and when it does, if you want to make the first flight yourself, you’ll have to demonstrate that you have recent experience in a similar type of aircraft. LAA Engineering can suggest suitable test-pilots though, if you’d prefer not to. If you’ve built an approved design, the flight test programme is typically accomplished in just five hours flying.

Yes, building an aircraft is an all-engrossing project that will require considerable personal effort, but to look out of the cockpit of your new aeroplane as the world passes by beneath you is a reward that’s hard to describe. If you want to do this, you can. Good luck!

Once you’re done building at home, you’ll need to find a way to get your project to the airfield. With access to a trailer, or by renting a 7.5 tonne truck, you can do this yourself… or there are firms that will move it for you

UK’s most popular kit aircraft

We looked at new kit registrations made with the LAA between August 2019 to July 2021 to see what the UK’s most popular kitplanes are…

  • While it’s not really a surprise that Van’s Aircraft, the world’s biggest kitplane company tops the list, what is interesting is that its two-seat tandem model, the RV-8/8A, which celebrated its 25th anniversary last year, seems to be enjoying a boost in popularity, with 15 new kit starts registered.
  • Sharing second place with 12 starts each, is the Sling Aircraft Sling 4/TSi and the Van’s Aircraft RV-7/7A. The Sling TSi seems to have caught many builders attention with its pairing of the Rotax 915iS with a four-seat cabin, giving a good mix of useful load along with an efficient turn of speed. The two-seat side-by-side RV-7/7A remains a very popular kit choice for the UK, following in the footsteps of the earlier RV-6, which still holds the record for world’s most popular individual kitplane.
  • Third spot with 10 starts belongs to the Van’s Aircraft RV-14/14A, its newest and most advanced kit. This two-seat side-by-side design is most commonly powered by a Lycoming IO-390 engine.
  • The Eurofox is fourth with nine new starts. This two-seat high-wing kit is fabric-covered and is available as nosewheel or tailwheel, with quick-fold wings.
  • Eight kit starts nets the Aeroprackt A32 Vixxen fifth place. This STOL high-wing two-seater is powered by a Rotax 912ULS and its large, highly glazed cabin offers great visibility.
  • Sixth spot goes to the Sling Aircraft Sling 2, with seven kit starts. This low-wing, two-seat machine uses the Rotax 912 and 914.
  • The Van’s Aircraft RV-10 and the Zenair CH750 share seventh spot. The RV-10 is a four-seater with a huge useful load and good short field performance thanks in part to a Lycoming O-540 engine. The CH750, and its latest Cruzer derivative is a two-seat, high-wing design, with excellent STOL capability.
  • Three designs share eighth spot with four kit starts each. The Bristell NG-5 Speedwing is a two-seat, side-by side low-wing machine with an aluminium airframe and uses a range of engines. The KFA Safari is a tube-and-fabric, high-wing two seater that’s been designed with rough-field use in mind. The wings fold to help with hangarage. The Van’s Aircraft RV-12/RV-12iS is a two-seat, low-wing aircraft that uses the Rotax 912, or the 912iS. Unlike the other RV models, it is assembled with pulled-rivets, and has removable wings. Power comes from an ultra-fuel-efficient Rotax 912iS.
  • With three each, the Kitfox Mk7 Supersport and Lambert Mission M108 share ninth spot and are remarkably similar. Both are tube and fabric high-wing aircraft with folding wings, and using Rotax engines. Build assistance is offered by Lambert Aircraft at its HQ in Belgium.
  • And finally, sharing spot number 10, is the TLAC Sherwood Ranger biplane and the TL Ultralight Sting Carbon S4. The Sherwood Ranger is a two-seat biplane kit that is made in the UK. A range of engines are available to use, if you want that ‘wind in your hair’ feeling! The Sting Carbon S4 is the only composite kit that features here. Its carbon airframe comes pre-finished in white, the low-wing, side-by-side two-seater can be powered by the Rotax 912ULS or 912iS.

Other ways to build…

A few other routes allow you to build an aircraft in the UK. The British Microlight Association oversee a number of sub-450kg 3-axis and flexwing types. Rob Mott, BMAA’s Chief Inspector told FLYER, “Currently, the British Microlight Aircraft Association (BMAA) looks after approximately 75% of all homebuilt (amateur-built) and 99% of factory-built UK Microlights. At the request of importers and members, BMAA started looking seriously at homebuilt microlights around the turn of the century. The popularity of homebuilding microlights surged with the BMAA introduction of the original X’Air. Others soon followed suit; the SkyRanger (Classic, Swift 1, 2, 3 and Nynja variants), X’Air Falcon, Easy Raider (discontinued), Air Creation (KISS, iXess, Tanarg & Bionix), Savannah MXP-740 (later VG – Vortex Generator), Escapade (now Sherwood Scout), EuroFOX (nose & tailwheel) and the Eurostar SL.

“Many people don’t realise that BMAA approves homebuilt VLA (Very Light Aircraft) – up to 750kg and 45kt stall speed. Numbers are increasing each year, the most common BMAA VLA is the SkyRanger Nynja, but Pipistrel is catching up with different versions of the impressive Virus SW.

“Overall, BMAA is approaching 800 projects, with around 80% completed and flying. As with factory-built microlights, our homebuilders can take full advantage of new engines, propellers and non-certified avionics. The fitment of touchscreen EFIS and autopilots becoming increasingly commonplace. BMAA has new 600kg and VLA designs currently undergoing certification.”

If you opt for a one of the single-seat de-regulated (SSDR) types, like the SD-1 Minisport or the TechPro Aviation Merlin, then you have total responsibility for the project. You can even build your own design. You’ll just need to register the completed aircraft with the CAA.

Talking of the CAA, there has long been a path to build and operate aircraft on a CAA Permit. Occasionally used for types that fall outside of the LAA or BMAA’s remit due to weight or horsepower, the scheme is not for the faint of heart, nor wallet…

How about building your own single-seat jet, powered by four mini-turbine engines? This amazing machine, the Conway Viper designed and built by Barry Conway shows just how much you can do within the allowances for the SSDR (Single-seat deregulated category).
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