Building "Cowboy Up", a Cheetah Kit

[Bigglesworth]

Heya Everyone.

 

Those of you who have been reading the other Cheetah thread will know that I am in the process of building a Morgan Aeroworks Cheetah kit. I have been working on it for a few weeks now and have realised that I have the time to keep an ongoing progress report with pictures and more. So, for the sake of anyone interested in buying one, or anyone who wants to learn form my mistakes, this is the thread.

 

Also if you want to track my progress and laugh at my mistakes, feel free to read it and post comments, questions and other things.

 

And if you see me making a mistake, For Goodness Sake TELL ME Before I Go Any Further.:)

 

I normally work on the plane on the weekend, so over the coming week I will try to fill in the basics of what I have already done. (and why I did it and how I fixed it up :)) Then starting next week, you will get a running commentary on what I've been doing.

 

As to the title of the thread; Cowboy Up is the name of my plane, I will paint it large on the side like on a BnS ute. Next to the RM decals.

 

Look forward to your comments, and to seeing you in the air.

 

Biggles

 

 

 

[Bigglesworth]

The Beginning

 

So I suppose the start is when I learned to fly. I have about 56 hour total spread out over 6 years on planes ranging from a Bantam to a C150. I have done my PPL theory but have only got my RA licence. I got this in a Gazelle which is a plane I enjoy flying but consider hopelessly slow.

 

Anyway I would have been content to hire planes from the club, but the airport is 1 hour drive away. By the time you get there the weather is sour.

 

So I wanted my own plane. Of course it had to be fast, flash, be able to land in a nearby paddock, and it had to be a chick magnet :)

 

Oh, and I had to be able to afford it.

 

That last one left my choices between a 2nd hand drifter or thruster; so much for the other criteria.

 

But I kept looking at all these planes I was dreaming of, and I started looking at kit planes. I mean, after all I was a part time mechanic and a carpenter's assistant the rest of the time; if I couldn't build a plane, then there was something wrong.

 

In any case, the kits were still too expensive, only the Cheetah seemed reasonable. And the fact that Garry answered all my questions about it, even when I told him that I couldn't afford it, made me want one even more.

 

And then, by Natfly 2007 I had a bit of money saved up from working 7 days a week, 6:30-5:00 so I figured I would check out this plane with a view to buying it.

 

I was impressed by the plane at Natfly. Garry took me for a spin, but I only have 56 hours, I can't tell what's good or not. I just liked the looks of it, and the performance specs, and I felt that, even though I might run into problems, Garry was a good enough bloke to get me out of them.

 

I sent off the deposit on the 27.4.07. 11 days after my 20th Birthday.

 

 

[pylon500]

Just a quick note, when using felt pens, be sure to remove before painting or doping fabric as the ink will tend to bleed up through the layers of paint, especially white!

 

Hey, maybe you want to paint it in COW colours.

 

Arthur.

 

 

 

[Bigglesworth]

Thanks for the tips, they will be followed, well, not the cow colours.

 

The name comes from the fact that I always loved that expression, for those of you who don't know it, it means bull***t off, just do it. Cowboy up and get on that bull, that sort of thing. And thats what it was like for me to take on this project. Also I see myself as a cowboy of sorts, and it should take me up.

 

 

[Bigglesworth]

A week in The Town With The River (Taree)

 

It took Garry about 4 weeks to get the kit ready after I sent the deposit, but it took me longer than that to arrange the necessary moolah, so it was the last week in June when I drove the 10 or so hours to Taree. (I won't bother you with the stress it caused me when my ute failed rego the week before I had to leave, just say lucky I'm a mechanic).

 

So I get to Taree

 

And I start work.

 

This plane really is incredible. By mid-morning I realised why there wasn't many photos available of the early construction stages: they were completed before I had time to get my camera out.

 

By the end of the first day, I had the walls of the fuselage built, and started to pull them together.

 

If anyone is going to build a Cheetah, spend some time at the factory. With Garry giving me directions I saved weeks of scratching my head, and I was sure of what I built. And, for the whole 6 days I worked there, Garry only charged me $600 for the privilege of telling me what to do.

 

Thats right, just $600 for saving weeks of time, getting a better job done, and learning heaps on the way.

 

And you couldn't ask for a better place to work in than the factory, plenty of space, all the necessary tools, good atmosphere; they even let me listen to my country and western music while I worked.

 

So back to work, the next 2 days didn't go so quickly. Gussets, gussets and more gussets, the basic shape was the same, just stronger,

 

On day 3 I started on the elevators. This was good because I hadn't done much fibreglassing and wanted to make sure that my standard was good enough. It was, but it was there that I made my first mistake: the root rib is angled and because of this angle it must be drilled 1/4 inch further back for the shaft. Mine isn't. Therefore my elevators are 1/4 inch longer. No big deal.:confused:

 

I got to the spars next. Or to one spar, I ran out of time for both.

 

The way to cut the angles down is first cut the bulk with a circular saw (messy job) then clean it with the power planer, and lastly sand it with a belt sander. Of course I thought I could do this better, I tried to smooth the edges with the planer. Uh Oh. BIG mistake. Firstly it took off too much from the edge and looked horrible, 2ndly, no safe edge on a planer: one deep chunk out of the spar angle. And now I have some rubbish aluminium to dispose of. :;)1: A new spar angle cost me $65 and I took better care this time. Warning. BE VERY SURE YOU KNOW WHAT YOU ARE DOING WITH A PLANER BEFORE YOU TAKE IT TO YOUR NICE NEW AEROPLANE!!

 

Then I had to put the spar together. The correct method is get the distance right at the start and the end of the taper, then make sure the angles are straight. I got this pretty right the first time, but one hole had to be slotted slightly (about 2 mm, solid rivet fills this).

 

Then I was running late, I wanted to do the solid rivetting before I left, so I needed to clean the parts off as soon as I could. Garry lent me a drill and some sandpaper and I did it that night. I was camping in the back of the ute so no problems with aluminium chips getting everywhere.

 

The Saturday morning was my last day. I got the the spar rivetted no problems, and then had to load the fuse on the roofrack and the rest in the back. It fitted but I had to put the camping gear in the front and could hardly see my mirrors.

 

But I made it home with everyone staring at me.

 

I enjoyed the trip, it was like "so what you have a WRX, I have something faster here, don't look down on me".

 

One big step done.

 

 

 

 

 

 

 

[slartibartfast]

Great start Bigglesworth. Garry told me you were a hard worker. Something about not even stopping all day to relieve yourself.

 

Keep up the good work and we'll see who gets there first. Hopefully it will be a tie.

 

Ross

 

 

[Yenn]

Looks good. Is it all solid rivets?

 

 

[BigPete]

Well done Bigglesworth - I enjoyed reading your report - keep us posted and hope to see you in the air soon.

 

regards

 

 

[Brett]

Well I hope when my kit aircraft arrives that I will have even half the enthusiasm that you obviously do :)) I have a plan to have mine built in around 12 -14 months but unfortunately I will only really get weekends to build as after work im usually to buggered ,,,thinking that building when tired may not be a great idea as its usually when mistakes happen...well for me anyway... Good luck

 

 

[Bigglesworth]

Looks good. Is it all solid rivets?

Solid rivets only in the spars and a couple in the rudder hinge, it was important for me to do some of them at the factory because I hadn't done solid rivetting before and had no idea about it. It is actually pretty easy but unless you know how much the rivets need flattening, you could easily make them too flat and crack.

 

 

[Bigglesworth]

The workshop and what goes on inside it

 

When you set out to build a kit aircraft, one of the main things is where will you have the space to build it. Garry built his in a single garage, but since it was full of tools, he had to work partly outside and I didn't like this idea. Might be alright during the day but when I'm working up until the wee hours of the morning ( only routine work [e.g. sanding] at that time of night, otherwise major mistakes are made), I want to be able to keep everything under roof, and closed off from the frost outside.

 

Luckily my boss (where I work as a small-engines mechanic) is a good bloke and he offered to let me use the last bay of the workshop. He even cleaned out all the dead motors for me. And got an electrician to put lights in.;)

 

No heater though:sad:.

 

So, waiting for me when I got home was an almost empty single bay, slightly longer than normal, which I could use exclusively for building in. All the tools I might need were in the workshop next door so I didn't need the clutter of tool storage, just the ones I was using at the moment (and, me being me, for the last week or so. I never seem to get around to clean up:;)1:).

 

So first I needed to equip it with a work bench. I made mine 1200x4000, and I'm glad I did. It means I have less floor space, but I can fit a full sheet on it which is very handy, and it has to be long enough to hold a full wing when I get that far.

 

We also made sure that the customers couldn't see the last bay, too many question take up too much time .

 

Then all I needed was a couple of small benches or trestles to sit the fuse on.

 

And all was set.

 

I also had to unroll the sheet metal........... BE VERY CAREFUL WHEN DOING THIS.

 

I had an empty patch of floor long enough, and there was me and my boss holding it; all should have been alright. But.......his mutt of a dog decided to get in the way, and we both reached out to get it out of the way at the same time, and SNAP ~ there went the metal. All would have been well it we had been unrolling straight, but life isn't like that. One side landed on a water pump............ Total damage: one crunched corner where it hit, plus 2 sheets with 200mm creases in the middle of them. OUCH :black_eye:. One sheet I was able to cut around the crease, with the other one, I put the damaged bit in the middle of the fold in the tail. After folding it, there is no more sign of the crease ;).

 

While on the subject of sheet metal: when I got home I didn't want to cut anything until I was sure of what I was doing so I kept looking at the cutting guide and the sheets I had left with increasing worry. You guessed it; I had cut way too much off for gussets. This is not clear in the guide since it has the cutting list for the single seater and then says what to do differently, but it is not very clear. So do your calculations BEFORE you cut. I can tell you now that you can take 500 off the 3rd 25thou sheet (1&2 are for the wings), then another 500 off one of the wing sheets, the other uses the end for the parcel shelf. Then if you are still short, there is cutoff from the edge of the wing sheets, that will work better than what I did. So, basically I needed another 4 pieces of 600x600. Not too much of a cost, but freight might be a problem. Not to worry; I was going to get a bit more anyway and sheet the inside of the fuselage, it looks better that way. I will get the sheets when I need them which is still a way to go. I might stuff up more and need another sheet on top of that;).

 

Basically the first few days I spent on the plane by myself, I wasn't game to do anything major, just put on more gussets and cut out what was marked, like the rear bulkhead and the firewall. Was good to get the firewall on, it held the front square, I have got the diagonals correct to 2mm which should be good enough.

 

The rear bulkhead I made slightly larger to the side of the head. When I was in the demonstrator, it was there that I was hitting. The Sierra uses a larger all round bulkhead and Garry offered to make me a tracing of this but I didn't want to add too much drag. I only increased it by about 7mm at the maximum point.

 

I also got joystick made, (it only needs a couple of holes drilled [the hard one is already done] and the stops cut to depth) and then could mount the elevator cable.

 

I was also spending a lot of time tinkering with bits and pieces trying to understand it a bit better. And writing emails to Garry with questions, comments and complaints. He must already be getting sick of me, but he has always helped me out to the best of his ability. More power to him.

 

 

 

 

 

 

 

[Bigglesworth]

Great start Bigglesworth. Garry told me you were a hard worker. Something about not even stopping all day to relieve yourself.Keep up the good work and we'll see who gets there first. Hopefully it will be a tie.

Ross

If it is to be a tie, you will have to work just as hard as me (or are you a lot quicker worker than me, probably). Are you prepared to work 9am-1am without longer than 1/2 hour for meals and other breaks?;) That includes checking my email accounts and replying to any comments on this forum.

 

Maybe you just get to work during the week, that leaves all my effort for nothing .

 

How's progress going on yours? I still haven't got around to doing a photoshop (or in my case GIMP) of my colourscheme, it would take me too long. And image manipulation is hard with only the touchpad mouse on my laptop. I take my laptop to the workshop and then can look at all the photos of Garry's plane to copy from. The problem is that Garry did a lot different (small things) from what the kit is.:confused:

 

{Note to all readers: Anyone who builds a kit should take a camera with them to the factory and photograph everything that is being build at that time, it is really helpful}

 

Keep working hard,

 

And feel free to post images of yours in my thread; you never can have too may pictures of these beautiful planes;).

 

 

[Bigglesworth]

....... In The Woods

 

The woodwork was next. That is the floor, seats and the cargo bay. The floor and seats are supplied but the cargo bay is optional extra since everyone has their own idea of what it should look like. Like me needing it big enough to fit in my guitar, and/or my swag and a gun rack.

 

So basically it is purty easy. First cut out the basic shapes, the lay them under the fuse, trace around them, mark where the gussets and uprights are, mark around these and cut. Using my carpenter's skills I got it down to almost perfect. Of course we couldn't have that, there was no way I could get it into position. So I had to take a bit off certain areas, all cutouts were made 45 degrees and then, with a lot of bending, it fitted in. Of course then, I couldn't get it out. So when I went to fit the rudder pedals, it needed a really short screwdriver (bit in a ratchet) to get some of the screws on.

 

Watch those pedals, the nylon blocks are a bit too tight. Before you put them on, trial fit them to the pedals, they should be firm but not too tight. When I fitted them the first time, it was hard just to move them, wouldn't have needed rudder trim, pedals will stick anywhere you leave them;). So I had to pull it all off, file them out, and put them back on. Also remember to lubricate the shafts with vaseline or similar.

 

Only when you are happy with the pedals should you rivet off the floor. When positioning the pedals, sit in it and find where they would be comfortable. And remember to take in account the seat upholstery; you can always put foam behind you, but it is hard to move the seat back.

 

With the seat, don't be too fussy as yet. I was, got it nice and neat, then I had to cut out more for the trim tab, and will need still more for the drag spar and the seat belts. Waste of time getting it nice now.

 

[attach]IMGP1067[/attach] [attach]IMGP1068[/attach]

 

The seats are held in at the front by a screw each which is threaded into the steel frame. I paid a bit of extra attention here and got the screw hole right on the edge of the frame. This means it will hold down evenly and look neater too. It is not necessary to be this fussy, but, thats me.

 

The cargo bay is choose your own adventure. Nothing is supplied for it. So first of all was a visit to the hardware, and believe me, after working with the quality wood that is supplied for the floor, all the common types of wood weigh an incredible amount. I eventually settled on a 3 ply for the bay since was the lightest they had. When I compared it th the seat, I found that the 3 ply was almost the same weight and nothing near the strength. But most likely only a fraction of the price. I decided not to bother trying to get the good quality wood and just use the the cheap stuff. For now anyway. Lucky I did too, because I would have had no chance of getting the stiffer wood in place.

 

I extended the cargo bay 1 section further than Garry, and to make up for the extra weight, I only put a small back on it. Now it fits a guitar, and longer things can be extended over the back provided;

 

a, they are lightweight,

 

b, they don't foul up the elevator gear (that leads to a small case of death).:black_eye:

 

[attach]IMGP0993[/attach]

 

So that was the easy part done

 

 

 

 

 

 

[Bigglesworth]

Decking my plane

 

If you are like me and have never done much with sheet metal before, you will understand when I say I was very scared of this phase of building. So much metal, so critical and so easy to get wrong. And my luck seems to be out to beat Murphy's; "even if its not possible for something to go wrong, something will go wrong".

 

As it was I needn't have worried overmuch. It was reasonable once I knew what I was doing. I started this job by annoying Garry by ringing him and getting his personal opinion on how it should be done and why the dimensions are wrong on the plan and what should be done about it.

 

So, basically the turtle (rear deck) was first, it looks harder, but because of that, it is easier. I started by making up the material for it by joining 2 sheets together and cutting out the right shape. The correct dimensions are: Front, the circumference of the bulkhead plus lap, Rear, 440mm (from plan, includes overlap), length, measure it, allow 15mm for cover at the rear, 10 for having to trim the front because I'm an idiot and it didn't sit square, and a bit more to cut off later, just for fun (thats rec. flying isn't it? just for fun?;)).

 

I had a mate to help me cut out the basic shape, so with his help we had to get it wrong. It was my fault really, but don't tell him that. See, I rough cut the section off the main sheet. Which meant that I didn't have a factory edge to measure from for the centreline. And believe me, a set square is ineffective above 1 metre.

 

In any case thats how we did it, then rivetted the sheets together (countersunk rivets, I used them in most places. They are not meant to be used so I will need to buy extra, Garry just wanted to save time for builders, but I want mine pretty). Later when I went to put the deck on, it didn't line up at the front bulkhead. Oh dear. Just where I wanted a nice factory edge.

 

I got it rough in position, marked the 2 sides of the bulkhead, took the sheet off, scored it with a Stanley knife, then pulled the strip off. Nice and neat.

 

The back end of the sheet has to be pre bent. this isn't hard, but it looks really awful and I was certain I'd regret putting creases in my nice shiny sheet. As usual with anything I'm certain of, I was wrong.

 

I tied ropes over the top to hold it down and G-clamped it to the longerons before rivetting it off. Only later I noticed that the front has the right lap (25mmm) but the back is supposed to have excess lap and the top should be at the specific height of "just above the elevator horn". So mine is high about 50mm. Big deal.

 

The front deck is only held to the front bulkhead, the rear one is just to give it shape and to fall over when I was trying to pull the sheet on top of it. In the end I cut out a template to hold it in shape and that still didn't work all that well. But I figured 'the rear bulkhead is only meant to be siliconed on, silicone fills large gaps'.

 

So I drilled and clecoed it off, then marked the front cutout for the cabin.

 

Took the sheet off, cut out the cabin, cleaned up the sheet, put it back on and Hey Presto!, it fits perfect. Don't ask me where that gap in the middle went, maybe it was needed in another life and that suits me.

 

I haven't rivetted off the front, I still need to get in to get to the fuel tank (another story) and things like that. So now it is clecoed and I have no more 1/8 clecos for use in other places. Remember: Even if you have enough clecos, BUY MORE CLECOS. You never know what they might be handy for.:confused:

 

On a side note, Clecos are totally unknown outside aviation. If you have any friends who thing they know about metalwork, talk to them about clecoes, they will be suitably squashed. Believe me, I've done it.

 

Anyway, now my plane has better curves than ***** ***;).

 

 

 

 

 

 

 

[Bigglesworth]

The tail of the tale, or verse vica

 

I have mentioned what happened to the tail in the other Cheetah thread. What I didn't say was that it wasn't my fault. It doesn't matter if I say this or not because no-one believes me anyway.

 

Basically, I took the shape off the plans and made all the measurements relative to the fin post when they should have been to vertical.

 

So it all is sloped back 5 degrees. Might even be better, I will wait and see because I am not changeing it.

 

To make the tail, I first found the centreline, then made the ribs out of sheet and rivetted them on. I rivetted them from the side of the tail which means the tail sheet has bumps in it. Could be better, but it will still fly.

 

I then cut out the tail plane, making sure to measure my plane before relying on the plan. And good thing, it needs to be about another 50mm wider.

 

So this was cut out, then the prebending. This is easiest to do free (not over a tube). I wasn't too keen about putting too much pressure on it with nothing to stop it folding, so I put one of the smaller canopy bars inside it which just sat loose and gave me peace of mind. The more pre-bending the better, so I tried to keep going until it sat perfect. But it was not to be. I put a 2x4 over it, stood on it, JUMPED on it, held onto something heavy and jumped on it, stood on it and pulled myself down. But it was all for not enough. At ~72kg I am simply not fat enough:;)1:. I need to eat more. But for now the tail is good enough.

 

I put it on, rough marked the base, cut that, then marked it again, cut it again, etc. etc. For about 4 hours. And it still isn't quite perfectly scribed. Later Garry tells me that you just put No More Gaps in the holes and don't bother being fussy. Its easy once you know.

 

It is the sheet which holds the tail straight, so line it up good before rivetting.

 

The forward fin looks easy. The bend I did tighter than the tail, so that the join would be better. At the front I stopped the 'legs' about 40mm from the apex which made a neater finish with the top bend in a straight line. I didn't work out exactly as I planned but No More Gaps will fix it.

 

The forward fin is rivetted to the fuse (at 3 inch centres I later found out. After I had done 1 inch;)) and also to the tail. I drilled and clecoed it to the fuse, and then drilled the holes to fix to the fin. Still wasn't smart enough. When I rivetted it down, the rivets pulled harder than the clecoes, and all the holes into the fin were out by about 1mm. Ran the drill through them and hope they expand to fill the gaps.

 

The rudder is also drawn the wrong shape in the plans. The top, same deal as for the fin, and the bottom, the rear corner is 100mm up fron the extended bottom longeron. Not, as I made it, from a right angle. Still, it looks alright, and Garry says he has never known his to 'sit down' on the tail, so I should be alright.

 

The rudder post needs to be tapered, I did this with a leather hammer, I think it will look smooth when it is covered, if not, it might need a bit of fill, but I doubt it.

 

The top nylon block fitted in easy enough. Only, I had a lot of lap on the fin sheet, so I wanted to keep the rudder back, I almost did it too far, the hole is borderline for edge thickness. But being nylon, the bolt will wear down first anyway.:)

 

Also, to even things out, I put the bottom end too close to the fuse and almost had to cut too much out for the stops. Again just borderline.

 

 

 

 

 

 

[Bigglesworth]

Up to date

 

There, now you know where I am up to.

 

Actually I have done lots more, but nothing major, so it will either be forgotten or covered as past details in future posts.

 

Tomorrow night is the start of the weekend:). Work on Cowboy Up starts after my main job and continues until Sunday night.

 

So now the posts will be real time. If you want to start adding comments, I would love to hear from you.

 

 

[Guest Flyer40]

You're an inspiration Biggles, I've been following your progress with great interest.

 

In fact because of the postings of you and Ross, I've been sufficiently motivated that I've been in touch with Garry and I'm going to Taree tomorrow to see the Cheetah in the flesh.

 

Keep the information coming, I'll never get tired of reading it.

 

 

[Thruster87]

Looking at your pics they don't seem to have any metal-prep [alodine etc treatment] is this what is the norm? and you mentioned using counter sink rivets but did you dimple or just counter sink the rivet holes? Just following your progress with interest Cheers

 

 

[Bigglesworth]

Looking at your pics they don't seem to have any metal-prep [alodine etc treatment] is this what is the norm? and you mentioned using counter sink rivets but did you dimple or just counter sink the rivet holes? Just following your progress with interest Cheers

I'm not treating the metal since it doesn't say to anywhere. I have no idea if this is normal or not since this is the first plane I have built. I once asked Garry about the corrosive properties of the aluminium and he said something about seeing it in use for many years without any corrosion, so I am hoping it will be fine without treatment.

 

The countersunk rivets are drill sunk everywhere except on the trailing edge side of the 'D' box sheet on the wing. This has to be dimpled. Basically, wherever it doesn't need to hold much it is just drilled, and when there are high forces, dimple it.

 

 

[Ultralights]

as an aircraft sheety by trade, i have never worked on a commercial or military aircraft that has untreated aluminium, absolute minimum is Alodine/Alochrome solution treatment and zinc chromate or similar primer. bare metal finishes are usually clearcoated, heavily waxed or coated in "corroguard" its a dull aluminium coloured surface treatment it can be seen on the surfaces of the wings on most airliners, and leading edges of stabilisers. the bare metal surface of the vampire is heavily waxed, but close inspection has shown signs of mild corrosion starting to take hold on some outer surfaces, especially in areas that are regularly handled, such the wing leading edge skins near the cockpit, tailbooms and areas you grab during pre-flight checks.

 

Even though aluminium provides its own protective layer of aluminium oxide, the oxide covering is very fragile, and where the coating is damaged, shaken loose, blown off etc , then corrosion will continue deeper in that area.

 

at least at an absolute minimum, treat and paint the areas that touch against or join parts of the structure or other skins.

 

for curiosity sake, the standard procedure for joining aluminum structures in Boeing aircraft is alochrome treat, zinc chromate prime, 2 coats of Polyurathane paint, then assemble wet with sealant before riviting, though Airbus and BAE use a non curing yellow barrier compound called JC5A instead of sealant. though im not sure how this would go with Recreational aircraft where weight is a prime consideration..

 

 

[Thruster87]

As a ex-LAME I also think it would be a great great great idea [almost compulsory] to metal-prep/treat in some way as ultralights suggested. Happy building

 

 

[Bigglesworth]

I asked Garry about protection and he said the secret was in the metal. Don't ask me what it is (ask Garry). Its not GA grade but it is easier to work with and has good enough corrosion resistance not to need treating.

 

Trust Garry to do something different which makes things all around easier .

 

BTW Flyer40, Garry tells me you had a fly in the demonstrator today, what do you reckon?

 

 

[Ultralights]

that sounds a bit strange! the secret is in the metal? if its aircraft grade aluminium it should be Alclad, the alloy is coverd with a layer of pure aluminium to help with the corrosion resistance, but any scratch, hole or cut will break the alclad and be a corrosion start point, if its not aircraft grade aluminium then it most likely would be 500 series alloy, which is a commercial grade alloy.

 

 

[Thruster87]

Magnesium in nonhardening type alloys (5000 series) makes them especially immune to aqueous corrosion [great for boat building /fuel tanks etc], but when present in the grain boundaries as an anodic magnesium aluminum compound, it may promote stress-corrosion cracking and intergranular corrosion and as such are generally not used for high stress aircraft manufacturing. Does sound a bit odd "the secret is in the metal" Cheers

 

 

[Guest Flyer40]

BTW Flyer40, Garry tells me you had a fly in the demonstrator today, what do you reckon?

I am very appreciative of Garry giving me a flight in the demonstrator and was impressed that he was happy for us to wander around the workshop and learn as much as we liked. We spent a lot of time checking out the Sierra that was under construction and looking desirable with hydraulic disk brakes and dual sticks. His knowledge and confidence in his abilities is kind of reassuring.

 

It was my first flight in an ultralight so it was as much about sampling ultralights as it was about sampling the Cheetah. It took me a few minutes to get used to using a centre stick with my left hand but Garry said I settled down on the controls quickly. Also took a few minutes to get used to the nose-low cruise attitude and stop climbing.

 

I'm no high-time veteran test pilot, but to me control harmony was impressive with light stick forces and no need for lots of rudder. Very sporty and easy to fly.

 

It was a little bumpy, which I appreciated because it gave me the opportunity to see how an ultralight behaves in those conditions.

 

My only criticism was that noise and vibration got really intrusive at cruise speed, compared to what I'm used to. However I think there were reasons for that and that its fixable.

 

However I now have a personal dilemma, and it's no reflection on the Cheetah which is an impressive aircraft. But after lapping up the luxury of a 182T with leather and glass, integrated autopilot on the G1000 etc..... well you know what I mean.

 

So I've got some serious thinking to do and lots of ideas to explore. I might be criticised for saying this, but regardless, how close could I get a Cheetah to a 182?

 

Mal