Soleair

That reminds me of last time I was in a street market in Bangkok. A guy was calling his display of watches, with the line: "Rolex watches - genuine copies!" I was tempted to buy one just for that. Bruce

ARV wanted to use aluminium rather than composites for the Super2 airframe. But it's hard to get away from a fairly boxy appearance when you're limited to curvature in a single plane (sorry). By using Supral, compound curvature of the aluminium components allowed the styling of composites, but manufactured in ally. Supral starts as a flat sheet. It is positioned over a female meehanite mould, sealed, heated to about 450º, & blow moulded to shape. Between the main frame, which supports the wings, u/c, seating, etc, and the firewall, where all the shaping & change of sections occur, there are only 4 components: the floor pan; 2 side panels, & the upper cockpit coaming. The floor pan included a tunnel (like you used to get as a transmission tunnel in older cars), through which ran the radiator plumbing. The side panels included 2 styling strakes halfway up. Both the floor tunnel & the strakes were there to stiffen the structure. The upper coaming embodied a constantly changing recessed channel that the canopy fitted into snugly. And yet all these details were included on the moulds, so instead of many small, fiddly bits of aluminium fabrication, these features, plus joggles where the panels joined, were all included in those 4 parts as formed. A massive saving in fabrication time, as well as the styling advantages. ARV was the first, and as far as I know, still the only Approved aircraft company to use superplastic aluminium in primary structure. Because of the 'eggshell' concept of the cockpit area, this material was amply strong & stiff enough for the loads imposed. Indeed, at least one ARV pilot crashed into trees, tore off the wings, & cartwheeled to a stop. He emerged unscathed from the cockpit. It may be that Alcan's legal eagles have since insisted that the material is not to be used as primary structure, but such is the impact of the litigious society on suppressing development. Bruce

Here is an example of a new engine in a new airframe (& here is one review from Flight Internationa). Conceived from scratch as an attempt to get away from using heavy, expensive American aero engines from the 1950's. No progress without someone willing to depart from entrenched tradition. Bruce *p.s. I'm 67. Does this count as old?

The problem of a cheap engine for ultralights has been around since these planes first started to appear. It was the cost (and weight!) of imported Lycoming & Continental engines that put off any but those with a large private income from building their own light planes. I built my first ultralight - a Pterodactyl - in 1978. The engine used as standard was a 350cc Sachs 2 stroke. It was light, nominally 25hp, but a bit of thumper as a single piston. The prop used was 36" dia, bolted directly to the crankshaft. The noise it made at high revs was deafening, due to the prop tips approaching supersonic speed. This setup didn't produce much thrust, so after I'd learned to fly the Dactyl (by trial & error, no schools or licences in those days) I set out to improve the thrust from the standard engine. I built a test rig using a spring scale to measure static thrust, which came to 70lb. I then built various reduction drives, using vee belts and toothed belts (I never used chain drive, because the combination of reduction ratio & power I needed exceeded Reynold's published figures). I played around with ratios, and made several different props. The setup I finished with produced 180lbs static thrust, using a 54" prop. (I subsequently bolted on a Robin 50hp engine, which with a 58" prop gave 280lbs.) After I'd put a few hours on this gear, I was approached by other Dactyl pilots, so made systems for them. Now, this is where what appears to be a fairly simple mechanical problem - that of building a reliable, light weight, & low cost reduction drive, begins to reveal its problems. I started getting failures, necessitating deadstick landings in remote paddocks. One of my customers was cruising at 2500' when his engine suddenly overspeeded. The entire reduction gear had detached, and subsequently went through the tiled roof of a house. I got a call from CAA (UK CASA), about 2 weeks later, that I'd rather not think about. The problem is fatigue. The Dactyl engine mount was very light & whammy, as was the entire airframe. The single cylinder 350cc engine was very lumpy. The airflow onto the pusher prop was far from clean, leading to asymmetric airflow into the prop. At certain revs, vibrations started to trigger harmonics somewhere in the system. This is always going to be an issue in a light structure with an engine producing any reasonable power, as the tail tends to wag the dog. Anyway, in the end I did get a system to work, at least for 120 hours before my beloved, & much modified, Dactyl died of other causes. The moral of the story is this. Yes, there are lots of small engines around that can be bought cheaply. Yes, at first glance, a reduction drive looks simple. But unless you have access to precision casting, milling & turning, and some pretty solid engineering nouse, it is much harder to make a simple, light, robust & fatigue proof reduction gear than you'd think. That's why the only retrofit bolt on redrives I know of that are sold are gearboxes, and they're not cheap. Nor would it be cheap to pay for the engineering needed to produce your own design. And incidentally, I have spent nearly all my working life as a mechanical engineer, and about half of that working with aircraft. Please don't write me off as someone who is saying 'it can't be done'. I know it can, because I've done it, at least with some degree of success. I'm just saying it's a lot harder than it looks, so if you go down that road, be prepared for a long & winding one. You might do better to look at direct drive, using a 4 stroke industrial motor (Briggs & Stratton & Honda, as well as numerous Chinese copies of these, exist in various power outputs. Motorbike engines too, might work). The downside will be the weight will approach what you hoped the thrust would be, and the thrust will be what you hoped the weight would be. Bruce

I built a MiniMax Eros, using almost only wood & sheet Dacron. I went for the kit, which is only lengths of wood & raw metal stock, so it's effectively scratch built. Mine took in excess of 2000 hours build time, over a 2 year period. No special tools. I made my own propeller. I paid around $5000US for the kit. Many people have tried converting motorbike engines. Almost nobody has succeeded in producing a reliable power unit. I bought the MZ202 engine, paying $5200. By the time you add instruments, paint, miscellanea, shipping, duty, & Greedy Suckers' Tax, my plane was over $15000 in the air. But I have to say, the fun factor is priceless! I think about the cheapest proper flying machine you could build today would be a powered GOAT, probably using a small PPG motor. Bruce

Oh dear! What a shame you have only eaten such poor quality Indian food. I too have had to walk out of an Indian restaurant after being served sad, boiled lumps of chicken floating in a thin gruel harshly spiced with raw chilli powder, all too obviously microwaved to order. Inedible, and yet the place was full of people apparently enjoying this travesty of a great cuisine. In fact, there is no such thing as just 'Indian cuisine'. Every region has its own distinct traditions. different meats, spices, herbs, vegetables, & methods of cooking feature depending on which region of the vast Indian continent the meal originates from. A true curry is prepared from individual spices, often freshly dry roasted before being ground & used at the time of cooking. Some meals need marinating for a few hours, but other than that a good curry will be prepared fresh on the day. No artificial colours or flavours are ever used in a proper curry: they simply aren't required because of the colourful mix of ingredients and the superb taste of a minimum of 4 or 5 spices, but often 15 or 20 herbs & spices used in a single dish. Fresh vegetables figure strongly, and the Indians have an almost infinite number of ways of cooking them. Ditto fish, prawns, etc, but it is not strictly against the Hindu faith to eat meat. Goat meat features strongly in Indian cooking, & it does curry very well. Hindus are forbidden beef, & Muslims pork. I do urge you not to write off this ancient, varied & infinitely rewarding treasurehouse of seductive spiced food. I strongly believe there could be very, very few people who would honestly prefer tinned pap & ersatz 'spaghetti' to a well prepared dish of proper Indian curry. Trust me, you are missing out on one of the best of all cuisines if you judge all curries on the basis of a few badly mass produced rubbish offerings. I blame the people who are prepared to pay for such insults to the palate with folding money: just say no! Incidentally, I'm not Indian, but have been an avid amateur curry cook for over 30 years. Done well, it's food of the gods, in my book. Bruce

That depends on the airframe. My MiniMax manages 75knots & 1000+ fpm on 60hp.

FT, in the statement you made which I quoted in post #186, you made no mention of the age of these engines. You made a bald generalisation regarding air cooling & 2-stroke technology per se being "bad". That was the self-evidently - and demonstrably - misguided assertion to which I was replying.

Better not tell that to the thousands of Rotax 447s & 503s reliably powering many RAA aircraft. Although they have collectively amassed hundreds of thousands of trouble free hours with their awful combination of technologies, they might realise they shouldn't be working and all suddenly stop.

+1 for Castrol TTS

Excellent resource, & very well written. Thank you very much for your time & effort in putting these notes together. Bruce

I can see two good points. . .

During a preflight on my microlight back in the UK in 1980 I found a shotgun pellet hole in my plywood winglet. There were some very antagonistic anti-aircraft people who lived in the housing estate next to the airfield I was based in. One of them was arrested for shining a mirror into pilots' eyes on final. Bruce

I can find no mention - & therefore, no prohibition - of the number or type of engines. So a replica scale version of an Airbus A380 jet is theoretically possible, within the other constraints of 95:10. And my 95:10 MiniMax "go's" 2 or 3 times a week, Nev. Bruce

95:10 does not limit type or number of engines. Provided you build light enough, multi engines & jets are not prohibited. Not sure how the licence rating would work, though. . . Bruce

Fair do's, Kasper - the ARV Super2 is a bit better looking than that!

Great questions, & the silence is deafening. I for one confess abysmal ignorance on this. I just stay below the yellow arc when it's lumpy. But as a single seater with max 10kg baggage at reduced fuel uplift my options for exceeding the envelope are perhaps more limited than some. No excuse, though. I look forward to learning more. Bruce

Bex, I'm trying to SAVE the 16 year old student $45,000!

Your proposed kit cost budget is $50,000. Having built your kit, you are allowed to perform some of your own maintenance on it, thus saving some money. Instead, you could buy a used rag & tube ultralight for as little as $5000. That leaves you $(50,000 - 5,000) = $45,000 to spend on maintenance until you break even on the two choices. And as Tony pointed out above, if you get your L1 ticket (at no cost) from RAA, you can do a lot of routine maintenance on your own aircraft. Obviously there's lots of differences between the example aircraft, but I was trying to point out the cheapest, & quickest, way to get into the air. I'm not suggesting you don't ever build. I've done it (see my avatar), & thoroughly enjoyed it. But the cheapest way to own an aeroplane it aint.

True. But you can buy an awful lot of professional maintenance for $45,000.

Good to hear of your enthusiasm for getting airborne. I'm sure you'll love it. Be careful of what seems 'common sense' as regards the cost of acquiring an aeroplane, though. In particular, buying & building every kit aircraft I know of is going to cost you waay more than buying used. There are often Jabirus & Cessnas around that are perfectly airworthy and that you could buy for half of your budget. And if you really want to have the most fun flying, at the lowest cost, look at some of the rag-&-tube ultralights that come up for sale from time to time. Thrusters, Drifters, or Trikes if you want to go weightshift. There's a 2 seat Quicksilver 3 axis for $16k over in Classifieds; a trike for $11k, & you can pay as little as $5k for an airworthy aircraft. It is of course essential to take advice from a suitably qualified person before you part with your hard earned savings, but there is no doubt that you will save a big bunch of cash buying secondhand over building a kit. Have a look through various market sites & you'll see what I mean. And instead of building for 2 or 3 years, you can be gaining experience in the air, which will help you decide what type of aircraft you want to build later on. Bruce

A taildragger does not have a tailwheel, just a skid. Hence the name. A.Pedant

The future is here, folks. . . DeLorean Aerospace DR-7 VTOL Aircraft

Impressive. But. . . what happened next? I wouldn't fancy manoeuvring on the ground in that wind.

Yes. Over here you can build under section 95.10 of CASA airworthiness regs. This means single seat, max gross 300kg, stall speed can't remember but maybe 40knots. The RAA run the ultralight aircraft. There is lots of info on homebuilds on their site. Cheers Bruce