Saturday, 13 October 2007

Download a copy of my Shoestring Pilot ebook and read about the entire build from start to finish.

The most expensive part of any paramotor is the engine. My machine uses a Yamaha KT100 Kart engine, which can be picked up second-hand very cheaply. Spares are inexpensive and easily available, making the KT100 a viable alternative to anybody considering building a paramotor, especially if you're on a tight budget.
With my tuned exhaust, redrive ratio and propeller combination, I managed to get a very respectable 55kg of thrust.
Read how I did it in my Shoestring Pilot ebook. --------->

----Scroll down to read sample pages of the book----

Friday, 12 October 2007

I need a plan!

Ok, after searching around on the internet for ages I came across three web sites that offered plans to build your very own paramotor or powered paraglider as it's also called. The first one was easyup which I've been aware of for a couple of years but never really felt confident enough with what was on offer to commit to buying the plans and after reading some pretty negative comments on the "out-dated design" I'm glad I stayed away.

The second web site I found offering plans to build a PPG (powered paraglider) was Skytribe which are based in South Africa, I really like the feel of this web site and it has some really useful info available and if I knew what engine I would finally end up with I would have definitely considered buying the Skytribe plans, I have subsequently spoken to Dave (the owner of Skytribe) for some advice on my engine choice (which I'll tell you about a bit later) and he has been very helpful and friendly (even though I didn't buy his plans).

The third web site I found (and the one I ended up going for) was that of Jeff Baumgartner's Skybolt design. I had a good look around the site and did quite a bit of research on the Skybolt and everyone seemed to agree that it's the best design out there for the D.I.Y. PPG builder and probably the best designed PPG yet. As well as the Skybolt being very strong and easy to build (helped by the fact you get a 2 hour step by step construction DVD with the plans) the frame is bolted together as opposed to being welded. This means that if (or more like when) the frame gets bent the damaged piece can simply be unbolted and a new section bolted in and you're ready to fly again, good ay!

So my mind was made up, and the Skybolt it is. So I ordered the plans and a week later they arrived from the US. I was very impressed with what I received, which was about 12 detailed drawings, x2 construction DVD'S and a copy of "Risk and Reward" all for $110.00 (£58.47) including shipping, I was well pleased and really eager to get going and build my very own flying machine. Before I start building the frame though I needed to decide on what engine I'm going to use, which I'll tell you about in my next post, until then bye for now :-)

Build cost so far £58.47

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Thursday, 11 October 2007

Choosing an engine.

I've decided what I'm building and am very happy with my choice of design, now I need to find a suitable engine.

A purpose built PPG engine like the Corsair Black Devil, Radne Raket, Simonini, Solo 210 etc are too expensive for my limited budget, even second-hand, so I'm going to have to look at alternatives. After doing a lot of searching, two choices were available to me, 1: a motorcycle engine and 2: a go-kart engine.

Motorcycle engines are easy to get hold of and can be inexpensive, so that is what I'm going for. A 125cc 2 stroke should do the job and as luck would have it, I was given just that, a Yamaha DT 125cc .

As you can see from the picture the engine was still in the frame and had been sitting in somebody's back garden for 3 years, so it wasn't exactly a good runner but hey, it was free. So I set about taking the engine out of the frame so I could see what was what. Once I had removed the engine I could see it was in pretty bad condition and water had got into the magneto and corroded the electrics, not good!

The more I stripped down the engine the more I could see that it needed a lot of work and money investing in it to get it running again. I also found out that the engine was only 12hp which was not going to be enough power for me, this combined with all the modifications I was going to have to make, made me decide this wasn't a good choice of engine, I needed something which was going to be a lot more straight forward to modify and had more power.

Build cost so far £58.47

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Wednesday, 10 October 2007

Animal Attraction.

Having decided that using a motorcycle engine wasn't for me, (although others have gone down this route), I continued my search for a more suitable engine. A few weeks had passed and in that time I had managed to sell the Yamaha DT 125 engine and frame to raise a bit more cash to put towards another engine.

A month later I came across a Briggs and Stratton world formula go-kart engine which was offered to me at a great price, so I jumped at the chance and put down a deposit only for it to be refunded back to me the next morning because it had got stolen from the guy's shed, what a bummer, I was very disappointed, I thought I'd found my ideal engine, as it needed no modification, it had just enough power at 14.5Hp, (which is the same as the Bailey 4 stroke PPG engine) and it was brand new, oh yes and a real bargain. In a matter of hours I'd found and lost another engine. In hindsight though it was a little on the heavy side with only just enough power and it was a 4 stroke which apparently don't make very good PPG engines. Well this made me feel a bit better.

Another month had passed when I got the chance to buy another B&S engine from the same guy but this time it was the 8 Hp Animal model. Nowhere near enough Hp for what I wanted it for but I brought it anyway as I knew I could resell it and make a bit of money to put towards my PPG fund.

So I'd got through three engines! but still didn't have anything to work with, until a couple of months later that was.

Build cost so far £58.47

Next page ->

Tuesday, 9 October 2007

I've found what I've been looking for.

When I first started looking for an alternative PPG engine I was aware that the Yamaha KT100 kart engine seemed quite a popular choice for some PPG builders, Skytribe even offer a set of plans designed around this engine and as I said in one of my earlier posts, "if I'd have known I was going to end up using the KT I would have considered using the Skytribe design".

The engine is 15Hp stock and with a bit of tweaking some say you can get it up to 20Hp. Also being a 2 stroke it's quite a bit lighter than the B&S WF four stroke I was going to use, and a much simpler design. The KT has a good reputation for reliability and seems more popular in America, Australia and some parts of Europe than they are here in the UK. So when one came up for sale on ebay I snapped it up. The engine had been fully rebuilt, came with a carb, airbox, exhaust and a brand new pull start all for £125.00, that will do nicely thank you.

Finally I've got an engine I can work with, it would have been nice to have a bit more Hp but as long as I get a decent climb rate I'll be happy, I'm not bothered about building a rocket ship, I just want to fly.

Build cost so far £183.45

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Monday, 8 October 2007

A prop - er job!

Before I can get started on building the frame I need to build a reduction gear mechanism and buy a propeller. A reduction gear is needed to reduce the speed of the propeller so it spins at its optimum rpm, above 3000rpm and the propeller becomes inefficient. The KT reaches 15hp at 10.500 rpm, so I need to reduce this at the propeller by 4.1 this will get the propeller spinning at 2625 rpm, which should be just about right.

But before I start work on the reduction gearing, I need to decide on a prop, sounds simple enough but there are a lot of variables to consider to gain maximum thrust. An adjustable pitch prop is the ideal solution because you can tweak the prop until you find the optimum pitch for your engine. Unfortunately these are too expensive for my budget so I'm going to have to find an alternative.

Weeks of research and lots of questions later, I've decided on a 48" x 23" pitch wooden propeller from tp-propellers. The prop is designed for the Top 80 PPG and as luck would have it, has the same rotational direction as the KT, I've had it made with slightly more pitch than the standard Top 80 prop, that way if I find that the engine doesn't get up to speed I can trim a little of the end a bit at a time until it reaches the sweet spot, (thanks Jeff).

So I ordered the prop and 2 weeks later it arrived and what a lovely thing it is too. Suwicha, from tp-propellers has been very patient in answering my million and one emails and I would have no hesitation recommending their services, and the price? £77.00 delivered, a real bargain in my opinion.

Next step, building the reduction gear.

Build cost so far £260.45

Next page ->

Sunday, 7 October 2007

Hanging around!

Well it's been a while since my last post but there has been some progress, although it's been rather slow and frustrating. After some thought I decided to get the redrive made at a machine shop as although I have access to a lathe I haven't used one since my school days. I had a very reasonable quote from overseas to make the complete redrive kit i.e. small pulley, large pulley including bearings and main shaft, belt, prop retaining disc and all the necessary bolts etc. I was told it would take around 2 weeks before it would arrive, so while I waited I thought I'd get myself a harness, I decided it was best to buy one before I start work on the frame so I can check that the fixing points are going to be in the correct place.

The Skybolt can accommodate many different harnesses including the Apco Skycruiser, which is what I decided to go for. Because the harness is such an important part of a PPG I decided to buy a new one and after shopping around on the internet I found that offered the best deal £220.00 including karabiners and shipping. The harness comes in 2 sizes M & L, as I am over 6ft I went for the large. The people at Aerolight were very helpful and the harness arrived from the US within a week of ordering, which is more than I can say for the redrive kit, 2 weeks and it hadn't arrived, 3 weeks and still no sign of it, 4 weeks more delays but promises it would be shipped soon, anyway I'll tell you more about the redrive saga in my next post.

Build cost so far £480.45

Next page ->

Saturday, 6 October 2007

The powers of reduction!

After many weeks of waiting the redrive kit finally arrived, this marked a milestone in the build as I haven't been able to move forward with building the frame until I had the redrive fitted to the engine. I was very excited and couldn't wait to open the box. When I did, I was mortified, as the kit was very badly packed and the hard metal parts had damaged the softer aluminium parts as there wasn't any padding and the parts had just been packed loose in the box! There were a few other problems as well, so all in all a real disappointment. It felt like I'd taken one step forward and two steps back.

I contacted the chap who made it and after some negotiations compensation was agreed. All of a sudden the £120.00 cost didn't seem such a bargain any more.
In the end the ratio turned out 1:3.8 rather than 1:4.1 which means the prop will be spinning a little faster than first expected but it will still be under 3000rpm, so it should be fine, hopefully!

Build cost so far £600.45

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Friday, 5 October 2007

The build begins!

Well the time has finally arrived to start building my frame. Quite a lot has happened since my last post, so I'll do my best to fill you in on the details. Originally I was going to be building a Skybolt but in the time it's taken me to get the parts together, Jeff the designer of the Skybolt has designed version 2. This incarnation is much simpler than the original using 100 less machined parts. It's still a bolt together construction and most importantly just as strong. Also the design is much better suited to my engine choice and needs very little modification to mount it. So even though its seems like it's taking ages to get things going it's worked to my advantage, so I suppose good things really do come to those who wait! Thanks again Jeff.

The frame is mostly made of aluminium with some chromoly steel tubing used in the joints, lower hoop and harness mount. The aluminium used is a grade known as 6061-T6 which is aircraft grade, cheap in America but expensive and difficult to get hold of over here in the UK, so after some discussions with various people I was advised that normal 6063-T6 grade with a wall thickness of 1.6mm would be a good substitute. It's cheap, easy to get hold of and bends real good. It hasn't got the same springiness as 6061-T6 but because of the bolt together design of the Skybolt V2 any part that gets bent is easily replaced.

Another compromise I had to make was with the chromoly steel, Like the aircraft grade ally I found this very tricky to source in the UK so I decided to use 1.5mm wall thickness mild steel instead, it will make the frame a little heavier but hopefully this shouldn't be a problem.

All I had to do now was try and find someone who would sell me the small quantity's I need, as most aluminium and steel stockists will only sell you around 5 or 6 metre lengths. After lots of phone calls and emails I finally found a place in the Midlands who would sell me exactly what I needed and at a very reasonable price of £65.00 including delivery, this also included the aluminium I needed for the engine and re-drive mount that I've got to make. I managed to get 11ft of 19mm mild steel tubing through a friend of my Dad's for only £3.00 which is remarkable as the cheapest I was quoted was £28.00, thanks Dad.

Nuts, bolts and washers were the next thing to source, on the plans American spec aircraft grade AN bolts are specified and as they do such an important job I didn't bother looking too hard for a cheaper alternative. I found quite a few companies in the UK who stocked all the nuts, bolts, and washers needed at a fair price (about £25.00) but I thought I'd shop around to see if I could get them any cheaper, which I did. I found a company in the States called who quoted me around £16.50 which included shipping and a few extra nuts, bolts and washers to boot. They were extremely helpful and quick in answering my emails and delivery took just 5 days, amazing. Also the money I saved would buy me my harness plastic end caps that I will need, (I'll tell you more about them in a later post).

All I need now to start construction of my V2 is a copy of the new plans (thanks again Jeff you're a star!) a couple of hole saws (19 & 22mm) that cost me about £15.00, a new blade for my saw, another £5.00 and a pipe bender which I brought many months ago off of ebay for £16.00 plus a 8x4 sheet of 22mm thick MDF to use as a work surface £16.00, oh yeah and some Scotch-brite pads to polish up the aluminium which cost me another fiver (ebay again).

So hey ho, away we go, I've been waiting a long time for this!

Build cost so far £725.00

Download a copy of my Shoestring Pilot ebook 
and read about the entire build --->

The shape of things to come!

Using 3D max, I have created an exact 3D scale model of what my finished PPG should look like, this should save me a lot of time and expense and means I'll be able to see how things are going to fit together before I start on the build. I've also used the program to design my re-drive/engine mount, making sure the thrust line is in the middle of the rubber anti vibration mounts.

So watch this space!

Download a copy of my Shoestring Pilot ebook 
and read about the entire build ----->