Design a plane?

[Deskpilot]

Good on ya Yenn. Let's all remember though, this is a design to tempt others into the world of 'ultralight' ugh, recreational flying and building, or visa versa. As has already been stated, we all have our wish list but that's not the point of the exercise. Remember KISS, don't come up with something radical such as cunards, they'll more likely scare others away. Easy build is probably the main factor to keep in mind, so only basic curves, if any. But there again, not a flying brick.

 

Perhaps first decision should be high or low wing and why. Irrespective of whether you agree or not, we go with the majority vote. Let keep personal build methods prferences out of it for the time being.

 

 

[dreemhi]

Ok, I think Deskpilot is probably right, everything needs to be simple, practical and cost effective.

 

Taking it one step at a time, I think it should be a high wing monoplane. My reason, from a non technical perspective, basically everthing then hangs below the wing and contributes to the ability to keep the blue side up. And why bother with two wings when you can lift the entire craft, including pilot, with one.

 

I'm eager to hear the opinions of others:yin_yan:

 

David

 

 

[pylon500]

Going back to the first post by Yenn I see this was initially a 'Design Concept' post which leads us to debate on layout, materials and construction methods.

 

The post then goes on to some preferences with regard to layout;

 

My preference is low wing, occasional 2 seater, tractor configured Jabiru 2.2 engine, minimal equipment ie. no DG. ASI(?) etc. Cruise at 90kts, safely use 600m strip, tailwheel configuration and of course be RAAus registerable.

Without having to do too much research on design, there is a kit available here in Australia that, with a little modifying, will fullfill all these requirements, although I'm not sure I'd want to fly an aircraft of this performance without an ASI ?

This would be Garry Morgan's CHEETAH.

 

Converting to a tail-dragger would be easy enough as the undercarriage is bolted to a steel sub frame.

 

This would just need to be extended slightly to carry the U/C at a forward position, and a little 'beefing' up around the rear fuse area would hold the tail wheel.

 

To get shorter shorter field operations, you may need to install flaps....

 

I have debated this with Garry on occasions, he says his engineer wants to add too much structure to carry the flaps, and Garry is happy with the weight and approach speeds currently available.

 

You would have to debate this with him yourself!

 

While I don't endorse any particular kits or brands, I have flown the CHEETAH and believe it shows a good starting point.

 

Have a look at;

 

Morgan Aero Works

 

Arthur.

 

 

[Yenn]

pylon500.

 

The comment initially by me about no ASI was a terrible slip up. I meant no Artificial Horizon. It would not be legal as RAAus registered without an ASI. Sorry about that, but your picking my mistakes is what this is all about. I know there are several suitable kits but my aim is to get a few people thinking and researching as a group.

 

For instance micgrace's idea of a simple wing is good but where would we find info on the wing? What coefficient of lift at what angle of attack etc.

 

Tomorrow I will sort out what we have and that should give us a high or low wing and we can take it from there.

 

 

[Guest brentc]

I think the home-built jet is a 75%? Panther replica. There is an article on it in the SAAA magazine from near a year ago. Kingaroy is correct.

 

 

[Yenn]

Having looked at your suggestions it seems that the preferred design would be:- Single seat, high wing, steel or aluminium tube with fabric covering and fibreglass cowlings, no flaps, 80hp engine, minimalist complexity and instrumentation.

 

Some want nosewheel without a steerable nosewheel to reduce complexity, but would it then need steering by brakes and would that be less complex?

 

A VW engine has been suggested and I have no current info on them. My preference is to go with a Jabiru 2.2 which is a proven engine, fairly light and also easily available. What do you think? For single seat we are looking at 190lbs for the passenger (86kg). I am using lbs as most of the available info is US and they are still in the stone age. Fuel for 4 hours which would be about 40 litres which weighs 62 lbs. A small amount of baggage would be needed, say 10 lbs, which gives us a load of 262 lbs. From Bill Whitneys design course he recommends that a single seater will have a payload of about 34% of Max weight. This gives us a max weight of 771 lbs.

 

Now we need a wing to lift that weight and it will have a max coefficient of lift of about 1.35 according to Bill although there are plenty of wings with different coefficients, but this will give us a start. An aspect ratio of about 6.5 to 7.5 is recommended and we need a speed of max 45 kts for RAAus registration.

 

The formula for wing area (S) is (2 * max weight) / (Rho * Velocity squared in f.p.s. * Coefficient of lift. Which is (2 * 771) / (.00238 * 76 *76* 1.35).

 

Aspect Ratio (AR) is Wing span squared / Wing area and should be about 7.

 

All the above numbers can change with different wing designs and we need to decide on a wing section and wether or not it should be tapered.

 

I will work out some numbers using NACA 23012 section which was used in the high wing Cessnas.

 

Time is running away from me today.

 

 

[facthunter]

Design a ?

 

Keep the chord parallel for simplicity, nice rounded tips and some washout will make it behave nicely when slow & won't cause a problem with a 90-95 knot aeroplane. Have an elevator trim tab as a backup to the elevators for safety and a decent sized fin & rudder. Remember a camel is a horse designed by a committee. N...

 

 

[Guest bazdavis]

As for me if I could I would love to design my own 2 seat highwing pusher anfibian ! now you not only have aerodynamic problems to solve but hydrodynamic ones as well.

 

 

[facthunter]

Design a seaplane

 

I reckon they have to be made of plastic ( everything else rusts) Is there anyone out there with experiences of operating in salt water?

 

Letting your mind wander for a moment, how would a scale walrus with a rotecradial look? You'd only need about half a lifetime to build it. I have a particular love of flying boats nurtured somewhat by having access to a relatives weekender at Kilaben bay, right opposite the Rathmines ramp where the catalinas lived during & just after the war. Catalinas & sunderlands (occasionally) were still flying in there. P.G.Taylors Catalina Frigate Bird 2 was prepared there. It was in pristine condition prior to being flown to Chile.

 

Being something of an urchin (in retrospect) if there was any inkling of activity with the Cats. a few of us kids would get out the row-boat & position ourselves over near the ramp to get in the way.

 

The service guys would have to come out in the black & yellow crash boat & tow us back over the other side out of the way, & we would get a good view of the proceedings & a nice high-speed tow.(Where are you Douglas Stivano?)

 

In a wonderful co-incidence, Guess what I followed into Avalon on thursday, That's right . The HARS. Black Cat. & then after taxiing across the main runway I was held, and the 1049 Superconstellation landed immediately behind me & the glorious sound of 4 dirty big wright radials being throttled back as the connie flared for landing rumbled through my fabric covered plane. Theres no sound like it. We are very fortunate to have this precious metal still flying. Sorry if this is a bit nostalgic It happens. Nev

 

 

[pylon500]

More for Yenn.....

 

Your numbers and request still feels a bit like a Morgan CHEETAH.

 

Fuel for 4 hours which would be about 40 litres

I'm not sure if you can get 10 litres per hour from either a VW or a Jabiru!

 

without a steerable nosewheel to reduce complexity

Most forms of nosewheel are a pain!, but if you must use one, have a look at the steerable nosewheel on a Victa.

It has direct steer, no scissor link, no trailing arms and a good caster angle which will respond to brake steer as well.

 

I think the Zenith machines use a similar system?

 

Tapered wings only if you want the extra work, as for the NACA 23012 section, it's OK, but maybe a bit thin from a strength and speed point of view?

 

I think the idea of 7 to 1 aspect should be looked at as a minimum, 8 to 10 will give better efficiency.

 

Arthur.

 

 

[Yenn]

Thanks Pylon500.

 

This started as an exercise to see if anyone was interested and has fizzled a bit. I must get in and do some more, but as it has been so dry and my dams are empty I have been dragging mud around the countryside.

 

I get 10l per hour from a Jab 2.2 in the Corby but it is only idling really so I will allow for more.

 

 

[dreemhi]

High wing, metal frame, 80 hp, its starting to sound like a Superpup/Aeropup, Bushbaby or Skyranger. From what I can see you are looking at about $40-50K for a finished unit(using everything new) for any of these. It would be sensational if we could come up with a design that any average flyer could scratch build for around $20K. Gary morgans Diamond, comes close. Short of going back to Weedhoppers and the like, anybody know of others?

 

David

 

 

[pylon500]

Having returned from Narromine, I could now also suggest having a look at a plane built by Richard Faint up in Queensland.

 

It's all metal, single seat, low wing with trike gear, and built for around $10k!!

 

See some photos here.

 

Arthur.

 

 

[Ultralights]

Would that be This aircraft here??

 

 

 

and Built for $10K!!! :;)2: great effort. looks like a really neat little airplane!

 

 

[Yenn]

That is quite an impressive looking plane. I think Richard used to fly a Vampire or some such twin boom, small engine plane, had lots of hours on it from long distance flights.

 

I have been a bit lazy lately with the project, been working out tail sizes, very slowly. My main occupation has been cleaning out my two dams. Every cloud has a silver lining, no wet season meand I can get rid of 2 feet of mud and all the nasty weed in the dam. It's slow work with an old David Brown tractor and a 5' blade, but it keeps me off the streets.

 

 

[wanabigaplane]

Hi BrentC. Thread closed, so answer here.

 

I bought the Tornado from Sunirmalya, who bought it from Chris.

 

Arthur Armour taught Suni to fly in it.

 

I am planning to put it on the market soon and get back to the Sapphire.

 

I met Chris at Narrowmine last year.

 

Jack.

 

 

[wanabigaplane]

Lil Tinny

 

Saw the above 'plane at Narrowmine.

 

Built by Richard Faint from Watt's Bridge.

 

He previously drove a Sapphire which I think exceeded 1000 hours.

 

There was an article on the Sapphire site about some of his exploits.

 

 

 

[wanabigaplane]

Ant Builder

 

Also seen at Narrowmine - start with a sheet of aluminium...Jack.

 

 

 

[Guest Prometheus]

I'd love a tandem two seat rectractable. A scaled down version of the PC-9A would be nice. 110-120kt's cruise.

 

I'd even paint it up in Roulette colours... without the "R" on the side of course.

 

 

[Yenn]

Prometheus that is a good starting point. It is just about what I would go for myself. How about making a start, just the basics?

 

 

[dreemhi]

Guys, when this thread started we threw in more ideas than anybody could handle. Since Natfly I'm convinced I would be happy with any aircraft that was there and if I had a choice I'd probably choose the one Dick Smith arrived in. The sad truth is the cheapest one just went up nearly 2K and out of my immediate reach. I've got ideas but I have to be the first to admit I don't really have a clue how to design an aircraft beyond concept sketches. Maybe there is a case for a designers forum, where those that know can share their expertise. Meanwhile where do I start in turning an idea into a viability? Or where can I buy plans for Richard's or similar design?

 

David:;)3:

 

 

[facthunter]

Design a plane.

 

We all have very different ideas of what we want and should start by looking at what is available, There's no shortage and the numbers grow almost daily.That is how dynamic this movement is and its a world wide phenomenon. N...

 

 

[wanabigaplane]

Google the PIK-26.

 

Now think aluminium wing on foam ribs

 

Fibreglass fuselage

 

45 HP hummel engines half vw engine.

 

Jack.

 

 

[Ultralights]

Foam ribs and aluminium skins, sounds like Micheal Colomban trade marks, he designed the Cri Cri, and MC01/Bambi series of aircraft

 

 

[Deskpilot]

I was thinking of foam ribs as well, with three alloy spars, leading edge, main and aileron/flap mount at the rear. Why flaps? We all want a minimum of 80 knots on a lower hp motor, so we have to rule out a high drag wing section. Now I'm no aeronautical engineer but that seem to add up to a high stall speed, therefore, flaps of some kind.

 

As for the fuselage and tail feathers, would a simple bolted alloy frame, shaped with foam and then fibreglassed, fit the bill?