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CHEAP DIY ULTRALIGHTS? FAIR DINKUM.


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I'm surprised at how expensive cheap ultralights are. My fascination in ultralights began with ''Those Magnificent Men in Their Flying Machines''.

 

Can anyone recall the Frenchman I think it was who flew sitting under the wing in between a pair of bicycle wheels.

 

The aircraft was wood, wire and cloth of some sort probably powered by a motorcycle engine or something.

 

I always imagined to build something like that would be cheap.

 

As a kid I remember my father bought me a go kart with a Victor lawnmower motor on it. People soon starting putting twin Mc Cullough? motors on them and priced us out of the fun of a family sport that anyone could afford.

 

It seems the same thing has happened with DIY aircraft.

 

Surely there is alternative motors to the Rotax etc what with the high revving high torque lightweight motorcycle motors available today.

 

Surely we can replicate those sort of flying machines cheaply.

 

Even home builders now use aluminium, Dacron? and Rotax motors. (Hence what I call not cheap)

 

Can't we use timber, lightweight canvas, bicycle wheels and a motorbike/lawnmower engine of some sort?

 

What are your views?

 

Maybe you know of aircraft built in this fashion.

 

Google ''Cheap Ultralights'' and you'll see that the cheap ones are all aluminium etc and still expensive.

 

I read of ultralights you can build in your backyard using materials and tools available in your local hardware store.

 

To my way of thinking a cheap ultralight should be able to be built for around $3000 and then that aircraft would qualify as cheap.

 

Or am I in fairyland?

 

 

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I'm surprised at how expensive cheap ultralights are. My fascination in ultralights began with ''Those Magnificent Men in Their Flying Machines''.Can anyone recall the Frenchman I think it was who flew sitting under the wing in between a pair of bicycle wheels.The aircraft was wood, wire and cloth of some sort probably powered by a motorcycle engine or something.

 

I always imagined to build something like that would be cheap.

 

As a kid I remember my father bought me a go kart with a Victor lawnmower motor on it. People soon starting putting twin Mc Cullough? motors on them and priced us out of the fun of a family sport that anyone could afford.

 

It seems the same thing has happened with DIY aircraft.

 

Surely there is alternative motors to the Rotax etc what with the high revving high torque lightweight motorcycle motors available today.

 

Surely we can replicate those sort of flying machines cheaply.

 

Even home builders now use aluminium, Dacron? and Rotax motors. (Hence what I call not cheap)

 

Can't we use timber, lightweight canvas, bicycle wheels and a motorbike/lawnmower engine of some sort?

 

What are your views?

 

Maybe you know of aircraft built in this fashion.

 

Google ''Cheap Ultralights'' and you'll see that the cheap ones are all aluminium etc and still expensive.

 

I read of ultralights you can build in your backyard using materials and tools available in your local hardware store.

 

To my way of thinking a cheap ultralight should be able to be built for around $3000 and then that aircraft would qualify as cheap.

 

Or am I in fairyland?

Maybe, maybe not. The first one I saw was on downwind in Las Vegas and he was sitting in a plastic chair on a piece of 2” round tube; he lived.
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I read of ultralights you can build in your backyard using materials and tools available in your local hardware store.To my way of thinking a cheap ultralight should be able to be built for around $3000 and then that aircraft would qualify as cheap.

Steve, When I built mine back in the mid-eighties I expected to be able to do it for $3000, in fact, it ended up closer $7000 and I had no expense on tools as the only tools I used were what I had in the shed at the time.

So far I`ve made 1 set of skins for my home built and 3 sets for my Drifter! each time the cost of materials went up! from memory, the last set for the Drifter cost me between $800 and $900 for materials alone so I reckon if I do another set it will be well over $1000... At the moment, with the value of the Aus $ it would probably cost around $3,500.00 for a set of skins, for the Drifter from America.

 

Surely there is alternative motors to the Rotax etc what with the high revving high torque lightweight motorcycle motors available today.Can't we use timber, lightweight canvas, bicycle wheels and a motorbike/lawnmower engine of some sort?

You can`t just get any engine and put it on an Ultralight! with high revving engines, you need a reduction gearbox, then you need to be able to drive a prop with it, Rotax`s are popular because they have a purpose-built gearbox, with mine, I used a Robin Fuji 440 engine and chose a timing belt reduction drive.

If you want to build a 95-10 single place Ultralight, as I understand it, you can pretty much choose the materials and the engine you want but I can`t see how anyone would be able to build a safe to fly Ultralight, for $3000.

 

You might find this site interesting! Rotax engines, Rotax 377, 447, 503, 532, 582, and Rotax 912 aircraft engines, parts & ultralight aircraft accessories.

 

Frank.

 

 

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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

 

 

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How inexpensive your aircraft is will depend on how much you are willing to do yourself, and how far or fast you want to go. Aircraft metal is not overly expensive, nor is aircraft hardware. It is possible to design and build your own under CAO 95.10 or CAO 95.55, but they've been making it harder. I you are really committed, you can make your own prop, and redrive fitted to whatever engine you choose. You will have to make compromises like trading an automotive/marine engine will save dollars but gain weight.

 

Don't expect it to be cheap if you expect someone else to make it for you.

 

It's not difficult to find all the information you need to educate yourself on construction techniques and basic designs, but you will find a lot of very negative people out there who will tell you that you just CANT use anything but an aero engine. Be prepared for those people, and don't bother arguing with them, because they will never be convinced otherwise.

 

 

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...you will find a lot of very negative people out there who will tell you that you just CANT use anything but an aero engine. Be prepared for those people, and don't bother arguing with them, because they will never be convinced otherwise.

I really wanted to go the BMW R1150 motorbike engine with a TakeOff redrive, but was put off by a South African flyer telling me they were fine - IF you don't mind mucking around adjusting it constantly.

I'm not mechanically minded.

 

 

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I guess it come down to what you are willing to do in order to aviate. If it came down to a choice between constant tinkering or not flying, I'm pretty sure I'll go with constant tinkering.

 

 

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If you’re looking for a reasonably priced 95-10 how about a ‘resurgem’ powered with the four cylinder 2stroke radial, take off and land 25kt cruise 50kt tricycle undercarriage Hyde. disc brakes, wet wings, trim and electric start $4,500ono. It’s sitting in my hangar, I’m now to heavy for it but am still flying the Lightwing.

 

Also have a 447 sitting all wrapped up to keep the hornets out

 

 

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Find a good engine cheap!.

 

Take a hacksaw to a four cylinder VW motor, and have 30 hp two pot motor, lots of people have done it, 1\2 VW :

 

What airframe?, Slow draggy type high wing "PUP"

 

Sleek low wing all metal."HUMMEL"

 

And composite ? : Swan Aeroplane | Modern Wings / with a 30hp motor, not many.

 

spacesailor

 

 

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Take a hacksaw to a four cylinder VW motor,

You can run the 4 cylinder case with just 2 pots, obviously a little heavier. There is a book and articles around for building a proper 2 pot VDub, as well as parts suppliers.

A 250cc MX motor with the gearbox hacked off (in minutes) that you can pick up with one hand would be my choice. Better still a 500, harder to get though. Plenty at bike wreckers dirt cheap. 50hp flat out but an easy 30 at reduced revs for long life. No difference in power, but the 500 does it easier. Simple 520 chain drive reduction setup. That's 2 stroke btw, stay away from the 4 strokes.

 

If you need more, then look at jetski engines, plenty of used ones around in large range of sizes and hp.

 

As mentioned above, go to the Goat website for ideas and free plans. the Affordaplane plans are around also. Look at the Ison Airbike too.

 

 

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How inexpensive your aircraft is will depend on how much you are willing to do yourself, and how far or fast you want to go. Aircraft metal is not overly expensive, nor is aircraft hardware. It is possible to design and build your own under CAO 95.10 or CAO 95.55, but they've been making it harder. I you are really committed, you can make your own prop, and redrive fitted to whatever engine you choose. You will have to make compromises like trading an automotive/marine engine will save dollars but gain weight.Don't expect it to be cheap if you expect someone else to make it for you.It's not difficult to find all the information you need to educate yourself on construction techniques and basic designs, but you will find a lot of very negative people out there who will tell you that you just CANT use anything but an aero engine. Be prepared for those people, and don't bother arguing with them, because they will never be convinced otherwise.

Good advice. Thanks
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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

 

 

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Thanks Bruce

 

I did have a look at the layout of the small hp/ light weight engines, & came to the conclusion the 1/2 VW @ 85bls/ 36kgs, was well developed plus a few manufacturer's, were putting out parts to supplement the build.

 

Now it's a high spec component supplier's with high prices to match. Two plug heads & Nikosil cylinders on an old VW do's seem overkill.

 

spacesailor

 

 

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