When is it going to fly?
Colin Goodwin Reports on progress with his RV-7 build, now on its wheels
How are you going to get it out of the garden?” and “When will it be finished?” have been asked more times than there are rivets in the aeroplane, but last weekend a pal asked a new one. “Do you think,” he ventured, “that you’ll be able to spend as many hours flying it as you have building it?” My goodness, that’s a cruel one. I haven’t kept a tally but looking at those who have, I must have spent at least 2,500 to 3,000 hours in the workshop. If I fly the RV 100 hours a year, which will take some doing, it’d take about thirty years before the flying time overtakes the building time. At which point I will be eighty years old. It is, I suppose, possible.
I left you last time with a shiny new engine sitting on its stand. Fitting the thing was a keynote moment, though almost an anti-climax. My block and tackle, purchased on eBay for thirty quid, looked convincing enough and so did the roof beams that I planned to attach it to. Nevertheless, the thought of the assembly collapsing and �20,000 worth of engine falling onto a concrete floor gave me nightmares. The easiest way to fit the motor is to fit the engine mount to the engine while the latter is on its stand, because the rubber mounts put up less of a fight. Once you’ve done that, you can lift the whole assembly and offer it up to the firewall. The advantage is that you’re then threading bolts through holes that are parallel. I fetched my mate Mike from next door and we had a go at it. Mike used to play rugby so he’s an ideal engine wiggler.
The roof didn’t collapse and the block and tackle did its Chinese makers proud. Just over half an hour of fiddling and the engine was securely bolted to the fuselage. Now, my goodness, she is looking like an aeroplane. Best of all, ahead of me is some proper mechanicking where I can bolt things together and make good progress.
The next job was to fit the undercarriage legs, which on a taildragger RV fit into tubes incorporated into the engine mount. The legs are springy steel and pretty meaty. To say that they’re an interference would be underplaying the wrestling match it took to get them to fit in the tubes. I tried lubricating them, Scotchbriting the insides of the tubes and more, but only elbow grease eventually got them inserted in the correct position. Fitting the wheels was easy, and now for the first time Dumbo is sitting on its undercarriage. Later the spats and leg fairings will be fitted. But now to the wretched cowlings.
At least you can repair fibreglass
Unlike the Perspex canopy, where big mistakes are virtually impossible to remedy, you can at least repair and rebuild fibreglass if you make a botch of it. Mind you, I hate the stuff so the last thing I want to do is start having to create bits from scratch. Better to take it carefully and measure ten times and cut once. The cowlings are supplied slightly oversize because it’s likely that no two fuselages are the same. I think with the hole-punched RV-7 kit they probably are, but it’s not too difficult to trim the cowling to the correct size. Here I would like to toast Albert J Dremel who, in 1932, founded the Dremel Company that produces the eponymous rotary tools (actually now owned by Bosch). A cutting disc in the Dremel cuts through fibreglass like butter and very accurately with it. I’m not going to take you through the weeks of sanding and cutting: suffice to say that after a lot of swearing and arm ache, the cowls fit very snuggly and I think should not contribute too much drag.
- 1 Ground tests for ZeroAvia's 19-seater’s eco-engine
- 2 Flight test: Piper PA-23-250 Aztec
- 3 100 years of Fournier: a history of aviation’s original ‘green’ promoter
You get some very sexy bits to play with at this stage. Like my Vetterman exhaust system. There’s a choice of a crossover four-into-two system or a four-into-four arrangement. I asked Mr Vetterman which system most people choose and he said the latter, which was what I wanted to hear because it looks like a V12 E-Type Jag’s tail pipes. They certainly look cool, I just hope they’re not too loud.
There are no set plans for the layout of the engine bay and where all the various pipes and hoses go. Design engineers in the car world use software known as anti-clash that tells them if one component is going to bash into another. For example whether a suspension arm at full compression will touch an exhaust pipe. It’d be handy to have something similar for this project. I had a near miss with one of the hoses that will direct cooling air onto the drive gears of my electronic magnetos. I carefully riveted the duct onto the baffle (we’ll come to the wretched job of fitting the baffles shortly) and worked out a route for the duct to follow. Only trouble was that I’d forgotten that the oil dipstick tube had not been fitted. A few anxious moments followed as I ran up to the office to fetch it and check that the ducting would fit around it.
Amazing tool collection
It’s amazing the number of tools that you collect on this journey. You can buy ready-made Aeroquip hoses, but I decided to make my own so that the lengths will be just right. I’ve a fetish for Aeroquip and its blue and red anodised fittings. I’ve bought a thing called a Koul Tool that was invented by an American hot rod builder for assembling braided hose. It cost �65 but it makes the job far easier and avoids you spearing yourself with the frayed ends of the braiding. You never see stuff like this?or any other tools, for that matter?for sale on Van’s forums. People seem to be loath to sell their tools when they’ve finished their projects, possibly because they think they might be building another aircraft in the future (which I certainly won’t be) or because the tools become mementoes of the struggle.
A new Van’s model, called the RV-14, has just been unveiled at Oshkosh. It is a bit like a 7 but with more space inside. Just as the 7 is a lot easier to build than the 6 that went before it (the RV-6 isn’t predrilled) I’ll bet that the new aircraft goes together even more easily, and that parts made for it fit with less fettling: the early baffle kit for the RV-7 came with hand-drawn plans and was, according to Peter Reid (a member of my support network), a ‘right challenge’ to fit. You have to do a lot of cutting and trimming anyway?but at least my kit has proper plans and instructions. The only snag is that the baffles are not designed to incorporate the air filter ‘snorkel’ that you use with a horizontal fuel-injection system, so you have to go off piste a bit with the assembly. Van’s has a technical helpline that you can call but I’ve found that if you’re straying away from the standard design the suggestions are less helpful.
Good to take a break
I’ve learned that it’s very good psychology to give yourself a break from a less enjoyable job by switching to a task that gives a quicker reward, so I put the baffles on hold temporarily and started on wiring up the engine. It’s pretty simple, thanks to Dynon supplying a fantastic loom with the FlightDek 180 EFIS. There are cylinder head and exhaust temperature probes to hook up, and then the various T & P senders, a manifold pressure sender and a few other gizmos. The P-Mags are fairly simple to wire up but there was one complication: because I had already wired the panel before I decided to fit these mags instead of mechanical units, I hadn’t allowed for a power feed to come through the firewall to the mags. Simple to do; just another couple of wires off the main fuseblock. The tricky bit is that I had to get underneath the panel to do this. Extremely uncomfortable and there’s a danger of getting wedged under there and having to wait until Mrs Goodwin gets home to carry out an extraction.
A few wonky rivets aren’t going to cause an aeroplane as tough as this one to fall apart in the sky. Just when pals suggest that because Goodwin has built it the wings might fall off. With eight close-tolerance bolts holding each one on they probably won’t. What would do for Dumbo and its builder is a simple mistake at this stage of the build. I read a scary tale in the Light Aircraft Association’s mag about a test flight that ended in an emergency landing because the nut and bolt holding the throttle linkage together came apart. Nothing as dramatic as an aileron coming off, but enough to cause a hairy situation that fortunately in this case resulted in no injury to occupants or aeroplane. Because I’m using a Superior engine instead of a Lycoming both my mixture and throttle cables are non-standard lengths and will require customised brackets. I’m going to get my engineering pal Jerry Parr from Booker to have a look at my set up, as well as my engineer. I suspect designated test pilot John Michie will want to have a good look at details like throttle cables, too.
Parr has been an enormous help. Ex-RAF, head of engineering at Booker and multiple Vans builder, Parr swaps a lifetime of experience for a curry and a couple of Cobras. His last visit involved a masterclass in tie-wrapping. I’ve never been able to tie a shoelace properly but I am now a dab hand with a tie wrap. Perhaps I should replace my shoelaces with them.
The old hands are right about the ninety per cent finished, ninety per cent to go. Now it really looks like an aeroplane with an engine on its front, seats fitted and an instrument panel that can be switched on, visitors think that it’s nearly ready for flight. Well, it’s nearer than it was. The RV UK website lists aircraft that have flown for the first time and a couple of months ago an RV-8 built by a chap called Bob Ellis took to the skies. I’ve been in contact with Bob since the beginning of my project and like so many people he’s been a huge source of encouragement. It gives you an enormous lift when you see someone else finish; someone who started at around the same time. It proves that it is possible and that those piles of bits do eventually all fit together.
Inspired by Bloom’s determination
On the other side of London, Bloom is beavering away with glue, wood and fabric. Nick is also a great inspiration. He’s building an aircraft that is totally different to the RV, but I love his approach and determination. He’s almost tempted me into painting Dumbo myself because, as he says, then you’ve really done it yourself. I think, however, that good sense might prevail and I’ll get a professional to do it. Specifically, Mick Allen at Turweston, who has painted many an RV.
The next time you read about it, ‘the aeroplane in a garden shed’ should at last be finished. Don’t ask me when that will be, because I’ll give you the same answer that I give to everyone: It’ll be flying when it’ll be flying.