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Advantage of a homebuilt if you cannot do any significant work on it yourself, and solutions?

I was asked this Q by a prospective pilot the other day.

It reminded me of this thread

One obvious solution is to use a company to do it. But then what is the advantage?

Going back to basics, the person may actually want a particular type which is a homebuilt. In my case, I would really like the Lancair Evolution (except that’s useless in Europe but that’s another story). In that case, you just have to get it, and do whatever it takes.

The first thing is that homebuilts are definitely not cheap. An RV or a decent small Lancair in a good condition can be €80k to buy, built. I don’t know what the kits cost. Since you can buy a (pre-GT) late TB20 for that, clearly people buy them for different reasons. And the reason I usually hear is operating cost.

But if you look at where ownership costs actually arise, it seems clear that the case relies on DIY maintenance. A given type of aircraft construction (say, aluminium airframe and a Lyco IO360, and for a reasonable level of safety, will require similar maintenance actions.

An Annual done by a company will come out around €3k. Nearly all the work is a visual inspection and, you hope, lubrication. Then you get remedial work but the cost of that is usually small unless the aircraft has had abuse in the past.

The 50hr service done by a company will come out around €500-800. I used to pay £600 12 years ago, IO540 engine, basic service (oil + filter = £100). 5-6 man-hrs labour.

So where do the owners who use a company achieve savings?

The other approach is to have a syndicate member who does the work, but fairly obviously he will get fed up with that sooner or later, unless there is some kind of a payoff. The payoff can’t be done as a share % offset because that is equivalent to a one-off payment whose “value” will eventually run out and then you are back to the start. So the other member(s) need to pay something on an hourly basis. The only scenarios I am familiar with where this works have been with syndicates around a certified type, and one of the members was an engineer. Such a payment (cash, obviously) would still be a lot less than paying a company, though.

Regarding flying costs, something like 75% of the DOC in Europe is simply avgas. To reduce that, you simply have to fly a smaller plane (cockpit volume).

The next Q is why one would want to fly a homebuilt, if there is no cost advantage. One can install more interesting avionics, but that is a one-off cost saving which will in any case probably be buried if you are buying one already built.

Administrator
Shoreham EGKA, United Kingdom

Not an expert on homebuilts, but here goes:

No TBOs, no ADs, no ICAs, no Part-M, etc. Generally no imposed bullshit from the respective CAA.

But most of all: one can use uncertified parts and compoments, which cost a fraction of the certified ones. Whoever has had the pleasure of paying outrageous money for, say, a ridiculous Piper trim switch, a Cessna gear bolt, an STEC autopilot or similar has wished for an uncertified aircraft.

Finally, the possibility of modifying (or having it modified, doesn’t matter) to one’s liking. Especially if EASA reg, and especially on rare types, there can be very few STCs.

Mainz (EDFZ), Germany

I am aware of the parts cost but looking at the picture I know, I have never changed a trim switch, a gear bolt, an autopilot, etc. I changed a landing gear pump for example but the Socata cost was about 2x the OEM (Parker) cost, a difference of some £500, which is hardly a huge factor on the whole landscape of ownership and flying.

And if you do have a plane which needs a lot of parts replacing all the time then you will be looking at a lot of downtime and not much flying. I fully accept these do exist; I know of plenty of owners whose planes spend a lot of time grounded – both certified and homebuilt. A number of people aren’t making the Carcassonne fly-in because they are grounded…

As regards TBOs, that’s mainly the engine, but there isn’t a TBO in Europe for private ops either. You can run on-condition. But would you run an RV or Lancair engine to 4000hrs with compression down to 20/80 and the oil filter filling up with metal, just because you legally can? On a plane which perhaps doesn’t have particularly brilliant low speed (forced landing) behaviour?

It’s probably true that on most registries you can disregard ADs but that brings me to the delicate issue of how much in savings one can make and still be relatively safe. Not many ADs can be really said to be totally pointless. The Lyco crankshaft AD may or may not be pointless depending on your cynicism on corporate behaviour; definitely the early serial numbers were hardened but not tempered and they did snap, but thereafter the picture is muddy, and yes the final list of crankshaft serials was probably a CYA exercise, but you don’t actually know that and if it wasn’t Lyco certainly won’t be revealing that. And many ADs have a trivial compliance cost e.g. top fuel line inspection (5 mins), the Socata landing gear bolt cutting into the spar (5 mins)…

That was my point about required maintenance actions not being that different.

Administrator
Shoreham EGKA, United Kingdom

A lot of the home builds run on Rotax 912S which burns a lot less fuel (20/h mogas). Yes, that means that the aircraft are lighter but that’s a price worth paying if it means that you can fly more hours without worrying about the cost.

I also imagine that many who can’t do any engineering would hope that in time they’ll be able to do the 50hr themselves.

So essentially they need to fund the annual only. The routine maintenance they will eventually be able to do themselves, and the cost per flying hour is reduced to a point where extra hours don’t really cost much.

EIKH Kilrush

Within the scope of this thread, better performance for a given purchase price and level of complexity is one issue. A decent finished RV7A costs $70-80K, climbs at 2000 fpm, cruises substantially faster than the typical GA retractable and does aerobatics, on 9 US gallons per hour. Or throttle and lean back to 6.5 GPH and still go fast up high. My alternate approach has been to cruise slower and climb slower… but I paid half as much to buy my certified type.

In the US, most owners of homebuilts do 100% of their own work, except for stuff which an A&P would also subcontract, e.g. propeller overhauls. The advantage is that you don’t need an A&P friend to supervise your work. You do need an A&P sign off for annual inspections if you didn’t build the plane, but that is often free. Also, you can build up engines yourself out of new and used components you obtain cheaply for various reasons. Components which can’t be legally overhauled often present no technical barriers to being rebuilt by uncertified methods. My alternate approach has been to have the A&P friend, fly behind a certified engine, but (again) pay half as much to buy the certified plane.

Also I don’t like seeing myself coming and going as I would in an RV7

Last Edited by Silvaire at 02 May 21:29

Peter wrote:

I would really like the Lancair Evolution

You certainly do not want to maintain the turbine yourself anyway, unless you have several years of experience working on them and a hangar full of special tools and equipment, that cost much more than one aircraft. To my knowledge there are no un-certified turbine parts available for turbines (except for a couple of turbines built from the ground up as non-certified), so maintaining the turbine costs exactly the same as any turbine in a certified plane. Even the un-certified turbines have only one method of fixing them: send it to the factory. There simply is no way for anyone without a “factory authorization” and the right tools and equipment to do anything useful on them (all the non-certified ones have FADEC for instance).

The Evolution is not really a homebuilt as such. It’s a factory built non-certified aircraft where you can spend a couple of weeks at the factory pretending to be a homebuilder. I really don’t see how operation or maintenance cost for an Evolution could be very much less than a certified single turbine aircraft. But, there is no EASA regime, so any odd mechanic can maintain it. The question is if you want any odd mechanic to maintain your € 1.5M turbine powered, pressurized aircraft ?

There is a point in complexity where the average homebuilder cannot follow anymore. That point is anything more complex than an RV. There are lots of very fancy homebuilts around, but they are not built or maintained by average homebuilders. Even the Rotax 912 is way too complex for people to fix themselves, but then, it very seldom needs fixing, in contrast to a Lycosaur.

What I mean is, as long as you are ahead of the aircraft technically speaking, there are almost no limit to what you can save in terms of maintenance and operation costs. The more complex the aircraft gets, the more reliant you are on others, or you would have to spend disproportional more time maintaining it. An RV or similar complexity seems to be at the sweet point where things add up (easy and cheap to maintain yourself or by someone else). An Evolution is way beyond that point.

ENVA ENOP ENMO, Norway

LeSving wrote:

You certainly do not want to maintain the turbine yourself anyway

A guy once based near me had a Legend Turbine, built as a way to reduce his maintenance hassles after owning and flying P-51s and T-28s over a long period. It was a beautiful well publicized plane into which he had sunk a lot of money and done meticulous work. From what I understood talking with him as he toiled away on it, the plane ended up being more trouble to maintain than those old warbirds… and eventually he sold it. My educated guess is that the plane may have cost him about a $500K loss.

Last Edited by Silvaire at 02 May 23:31

One of my criteria in looking for a homebuilt, was that I wanted an aircraft that had no parts that could only be sourced from the factory (some do). For example, on mine I’ve had to get fairly substantial parts of the landing gear rebuilt and I’ve just finished a complete tailwheel assembly. It certainly tends towards the ‘simple’ end of the spectrum, which is perhaps why the formula works.

There’s clearly going to be a level at which you say ‘enough is enough’, and if I were to break the spar I would sell it on as a project. But at least it means you’re unlikely to have to scrap the plane for want of a single part that isn’t made any more. Even though I’m limited in terms of things I can adjust without getting them signed off, I’m not limited in terms of the work I can theoretically do myself. And in practical terms, that means a fair amount.

Also, £500 may be trivial if you’re aiming at something sufficiently high-end, but a lot of aircraft simply aren’t like that. For my Turbulent, most people who need new wheels go for AZUSA go-kart wheels which are about £50 a pair in contrast to wheels for certified aircraft that seemed to start at £1000 or so. An aircraft like that costs £6000 or so. Hangarage round me is about £1200 a year, so £500 here and £1000 there on certified parts would certainly change the economics of ownership.

Last Edited by kwlf at 03 May 00:35

You certainly do not want to maintain the turbine yourself anyway, unless you have several years of experience working on them and a hangar full of special tools and equipment, that cost much more than one aircraft.

That depends on the airframe. The PT6 will never be cheap to maintain, obviously. The rest of the plane… it depends on what is in there, and the build quality will largely determine how much of it will periodically fall apart. The one I saw close-up had a very high build quality (like the Lancair/Cessna 400). It was way above the homebuilt Lancairs I have seen before which were much closer to the traditional fibreglass homebuilt standard.

There is a point in complexity where the average homebuilder cannot follow anymore. That point is anything more complex than an RV. There are lots of very fancy homebuilts around, but they are not built or maintained by average homebuilders. Even the Rotax 912 is way too complex for people to fix themselves, but then, it very seldom needs fixing, in contrast to a Lycosaur.

That depends on the ability of the owner and what resources he can put together. Almost nobody would work on a Lyco engine. It goes to an engine shop… and whether a Lyco needs fixing or not is determined by its operation; it is nothing to do with the plane it is mounted in.

But at least it means you’re unlikely to have to scrap the plane for want of a single part that isn’t made any more

That is not so hard to achieve – if you have a total “owner manufactured parts” concession, without needing to obtain/generate supporting design data which is what is required for the certified N-reg version of it (rendering it nonviable in most really useful cases).

But you need quite a lot of resources and expertise to be able to make your own bits. I have a workshop with a lathe, a turret mill, a drill, 2 bandsaws, a TIG welder, etc, but I would not use that to make the case for a homebuilt to an average mechanically-minded person.

Getting back to my OP, I can well see that at say a < 10k purchase price level, a homebuilt is a really good way to go. If you bought a PA28 for 10k (which is possible) it would be a very shagged one, and a money pit. But what about the 50k-100k range? That is where most of the homebuilts with a reasonable performance exist.

Administrator
Shoreham EGKA, United Kingdom
some £500, which is hardly a huge factor on the whole landscape of ownership and flying

To some people, that means 10 hours of flying … not negligible. Again, one person’s truths may not apply to everybody.

EBZH Kiewit, Belgium
49 Posts
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