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jedi

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Aug 8, 2009
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2,225
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Sahuarita Arizona, Renton Washington, USA
I am looking at a long weekend with stay at home orders and expect we may all have an interest in some stay at home aviation entertainment. What could be more interesting than to design the perfect aircraft. As stated many times aircraft design begins with mission specifications.

OK, The clock is running. What are the specifications for the perfect virtual aircraft.

Rules:

1. It must be affordable. Not saying by who or how much it could cost but is must be cost effective. A bicycle is cost effective, A car is cost effective. To some, a boat is cost effective. To even fewer individuals an aircraft is cost effective. A train is not cost effective.

2. It must not violate normally accepted physical principles. F=ma, E=m(C squared), entropy/enthalpy theory, etc.

3. It must function on planet earth within existing physical parameters. No Zeppelin masts on top of tall buildings. That includes Sky Car charging stations.

4. It must be new design requirements. No physical item shown on the internet can meet these specifications.

5. Reserved for additional rules.

Specifications required include

1. Minimum, maximum and designed range and speed.
2. Occupant capacity.
3. Maximum empty and gross weight. or payload. Edit: Per post #8.
4. Maximum operating cost and purchase cost.
5. Storage requirements.
6. Any additional limitations to be avoided.

Note: It is ok to reference and existing design. For example; a tailwind with 45 knot stall speed and wings fold in less than 5 minutes with no more than 25 pound weight increase and 10 hours build time.

Or, A Cessna 150 with room for two, 220 pound occupancy and no more than 150 hp. Other specifications the same except cruise speed of 100 kts.

Be reasonable!
 
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jedi

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Aug 8, 2009
Messages
2,225
Location
Sahuarita Arizona, Renton Washington, USA
That's the beauty of it. No design is necessary. Only mission specifications within some reasonable possibility.

The goal is to determine where design effort is desired. Do you want more speed, better storage, less initial cost and what are you willing to give up.

I would settle for FAR 103 specifications if it could be taken in and out of my driveway and fit in the garage and cost only $10,000.

Ok, a little more. Cruise speed of 45 mph or greater. No paraglider wing. Takeoff and land within 500 feet standard day, climb 300 feet/min, not noisier than a motorbike.

The specifications keep getting refined. This is a design by committee that will result in several widely different aircraft and hopefully something more that one member would like to have.
 
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Hot Wings

Grumpy Cynic
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Retractable gear that can retract for loading. The ideal plane needs to be as easy to enter/exit as any existing auto. Durand Mk V with such a gear would be one example.
 

Tiger Tim

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Apr 26, 2013
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3,409
Location
Thunder Bay
I want a cheap hot rod with room for my giant self and a carry-on size bag. 400nm range, cruise at 150 knots, 4gph or better, tolerant of Avgas and Mogas. All the better if I can be flying for less than $15k after some creative scrounging.

I’ve often wondered if a Corvair-powered Davis DA-5 would get close to that.
 

Victor Bravo

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Jul 30, 2014
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KWHP, Los Angeles CA, USA
I propose the sheet metal "equivalent" of the Luciole, also known as 21st Century Moni:

  • Single seat, minimum 85 MPH cruise, 100-110 reasonable target
  • 30HP mildly tuned/massaged small block V-twin, to yield a $3500 finished cost for the engine and upgrades
  • 22-25 foot span, non-exotic / non-twitchy / non-temperamental airfoil
  • EITHER folding wings OR rear fuselage removes with screws (Nemesis 1 racer) to fit in trailer or container
  • No 3D metal stampings, a handful of foam/glass fairings are fine, F/G cowl is fine
  • At least 75% blind rivets, flush or button head, 25% AN rivets OK in spars, cockpit/crash cage, firewall, etc.
  • Scratch-Buildable with ribs hammered over wood blocks, bent angles or common extrusions, 2D curves in all aluminum parts
  • Target of $2000 max in raw aluminum sheet and extrusions for primary airframe structure (fuselage, wings, tail, controls)
(I'm actually cheating on the OP's hopes for a totally new discussion, the above was also precisely what I was trying to shove down everyone's throat in the 21st Century Volksplane epic)
 

mcrae0104

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3. Maximum empty and gross weight.
I would modestly suggest that Wo and We (requirement #3) are not requirements for GA aircraft; rather, they are the result of other specs such as payload, range, speed, etc.

Unless there is a common set of needs, of course, this exercise cannot result in a single aircraft design. But, FWIW, the "fixed points" for my own project include the following. We each have a slightly different mission.
  1. Vso 60 mph, Vne not important (it is a result, not a design point), Vc 175 mph, range 600 sm min.
  2. single seat
  3. We & Wo disregarded; payload = 275 lb, provide space for two carry-on sized bags (extended travel/camping) and one folding bicycle
  4. Operating cost max: $75/hr including fuel and engine rebuild fund, all other costs excluded; purchase cost: $35k airframe raw materials, engine, avionics, instruments, etc.
  5. Storage: standard T-hangar acceptable. Removable wings required due to workshop limitations and not intended for regular dis/re-assembly.
  6. Other limitations: not less than 1,000 fpm climb at S.L. because I will be operating at much higher DA than SL/SD. Must be able to fly into LXV in summer weather.
 

jedi

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2,225
Location
Sahuarita Arizona, Renton Washington, USA
I would modestly suggest that Wo and We (requirement #3) are not requirements for GA aircraft; rather, they are the result of other specs such as payload, range, speed, etc.

Unless there is a common set of needs, of course, this exercise cannot result in a single aircraft design. But, FWIW, the "fixed points" for my own project include the following. We each have a slightly different mission.
  1. Vso 60 mph, Vne not important (it is a result, not a design point), Vc 175 mph, range 600 sm min.
  2. single seat
  3. We & Wo disregarded; payload = 275 lb, provide space for two carry-on sized bags (extended travel/camping) and one folding bicycle
  4. Operating cost max: $75/hr including fuel and engine rebuild fund, all other costs excluded; purchase cost: $35k airframe raw materials, engine, avionics, instruments, etc.
  5. Storage: standard T-hangar acceptable. Removable wings required due to workshop limitations and not intended for regular dis/re-assembly.
  6. Other limitations: not less than 1,000 fpm climb at S.L. because I will be operating at much higher DA than SL/SD. Must be able to fly into LXV in summer weather.
Thanks VB and mcrae0104. Those are good starting points. Lets put in some likes and suggestions.

Modification accepted: Specification #3 3. Maximum empty and gross weight or payload.

Thanks to all for comments. The hope is to get enough support for a set of specifications that a follow on design study might be considered.

It might be a good idea to create classes of interest such as FAR 103, Light Sport, EAB, Reno racer, A to B transportaton, etc. Across the pond and Down Under add in here; SSDR, EULS, etc.

In the end, BC (Before Christmas), points can be tallied to see where there is enough interest to do more than a one off design.
 

pictsidhe

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Jul 15, 2014
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North Carolina
I know that I am not the only person wanting a trailerable aircraft. Making it simply fold into garage would really make it popular.
Type?
I'd usually like a sport plane. Bush planes look like they may be fun in areas that aren't split between trees and people...
Engine. Lots of cheapskates here. For a single place, a good industrial conversion would be popular.

I'm already working on the 'perfect' 103 sport plane 😜 A bush 103 may follow that.
 

Hot Wings

Grumpy Cynic
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Nov 14, 2009
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Rocky Mountains
A companion thread to this one might be a Vaporware powerplant?
Pictsidhe noted that many of us are satisfied, or will be, with a converted industrial. This limits building the plane I would really like to have as it needs more power. and there are no cheap water-cooled industrial engines suitable for conversion.

A quick detach rear fuselage, a true 60 hp water-cooled engine, a constant speed prop and some flutter mitigation modifications would make my Quickie project (at 1.2 scale) pretty much ideal ............... for one plane in my quiver.
 

BJC

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Oct 7, 2013
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12,020
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97FL, Florida, USA
1. Minimum, maximum and designed range and speed.
2. Occupant capacity.
3. Maximum empty and gross weight. or payload. Edit: Per post #8.
4. Maximum operating cost and purchase cost.
5. Storage requirements.
6. Any additional limitations to be avoided.
Vs of 50 knots or less.
Vne of 200 knots
Range with internal fuel, 300 nautical miles.
External tank for additional 200 nm.
Single seat.
Low wing, conventional LG.
Empty weight of 650 pounds or less.
Aerobatic weight of 1,000 pounds or less.
Max gross weight of 1,200 pounds.
Operating cost is too subjective, but:
Lycoming IO-360 BXX with P Mag ignitions
Fixed pitch prop, pitched for 3,000 RPM max straight and level at SL.
Inverted fuel and oil.
Total loss electrical system, with EarthX battery, light weight starter.
Cost less than 1/3 of a new DA 20.
Span NTE 26 feet. Fit in a standard T hangar.
Minimum electronic instrumentation.
No radios or nav equipment.
Limit loads of +10 / -8 g.
Va of at least 140 knots.

Edit: Add symmetrical airfoil and tapered wing, with (almost) full span ailerons.

Build it, and I will buy it.


BJC
 
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Hephaestus

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Jun 25, 2014
Messages
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Location
YMM
I want a cheap hot rod with room for my giant self and a carry-on size bag. 400nm range, cruise at 150 knots, 4gph or better, tolerant of Avgas and Mogas. All the better if I can be flying for less than $15k after some creative scrounging.
This has been my 'mission' project for a decade now, Since I was doing the commute to the oilsands. But I always seem to be getting distracted by side quests. Except I still want 200+kts, but there's always throttle back for economy :)

I've had a simplified rohr 2-175 sketched out forever with a yamaha 4 cyl on the back. But once you take the duct out - the rudder becomes much harder to get looking 'right' (and I don't like the tip winglet/rudders option). The big delta gives you that sqft'age to keep TC off your back calling it high performance with enough fuel to make a long haul.
 

pictsidhe

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Messages
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Location
North Carolina
Vs of 50 knots or less.
Vne of 200 knots
Range with internal fuel, 300 nautical miles.
External tank for additional 200 nm.
Single seat.
Low wing, conventional LG.
Empty weight of 650 pounds or less.
Aerobatic weight of 1,000 pounds or less.
Max gross weight of 1,200 pounds.
Operating cost is too subjective, but:
Lycoming IO-360 BXX with P Mag ignitions
Fixed pitch prop, pitched for 3,000 RPM max straight and level at SL.
Inverted fuel and oil.
Total loss electrical system, with EarthX battery, light weight starter.
Cost less than 1/3 of a new DA 20.
Span NTE 26 feet. Fit in a standard T hangar.
Minimum electronic instrumentation.
No radios or nav equipment.
Limit loads of +10 / -8 g.
Va of at least 140 knots.

Build it, and I will buy it.


BJC
That wasn't looking too far from an RV-3, until I got to the g loads. Perhaps with a wing upgrade?
 

BJC

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That wasn't looking too far from an RV-3, until I got to the g loads. Perhaps with a wing upgrade?
Close.

I edited my post to include “Edit: Add symmetrical airfoil and tapered wing, with (almost) full span ailerons.”


BJC
 

pictsidhe

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Close.

I edited my post to include “Edit: Add symmetrical airfoil and tapered wing, with (almost) full span ailerons.”


BJC
An enlarged One Design wing might be good. Maybe in metal. Thicker than the RV3 and tapered, so would allow more g before adding more spar.
 

REVAN

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Dec 6, 2016
Messages
226
Location
Tucson, Arizona USA
I would like a Part-103 compliant ultralight where no pilot certificate, aircraft registration, insurance or taxes are required.

Like a paramotor, it would be cheap to purchase ($8k to 12k price range) and it would store in my garage. Unlike a paramotor, it would handle windy conditions and turbulent air with grace and safety, and it would have very nice control and handling characteristics in all flight modes (especially at stall).

It would be capable of cruising at 48 to 55 mph, but would also be capable of flying slow enough for foot launching and have good off-field performance, because I generally don't want to use it at airports unless attending an airshow, or fly-in. I'd prefer it to have an easy foot launch where I can just run off the ground, but something with bush capable landing gear could be acceptable as well.

It would fit in a cargo trailer, or possibly even the back of a pickup, with no more than 2 minutes of preparation to go from transport to flying configuration, or back. It would be resistant to hangar-rash, or in this case trailer-rash, and also be quick and inexpensive to repair if something does happen.

It would have redundant propulsion for safe operation at low altitude and over hostile terrain. It would run on 87 octane mo-gas without expensive 2-stroke oil mixed in, and be able to squeeze 2.5 hours of cruise out of 5 gallons of fuel.

It would be easy to convert it over to float operation so I can fly it off the water when I want to do that, and it should also be able to carry camping gear in case I want to use it to go camping on some remote mountain lake.

How does this sound to the rest of you-all? Am I alone, or is my 'perfect aircraft' perfect for you too?
 
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Hot Wings

Grumpy Cynic
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Rocky Mountains
Other than the redundant power a part 103 gyroplane with a good pre-rotator could fill most of the above list of wants.

Regarding the 60 Hp VW engine: (thread drift)

I've got all the needed tools, a collection of cores and the experience to build them.
Unlike Pops I've just never been able to emotionally bring myself to feel comfortable with one for aviation use. I've seen too many broken ones over the years, both ground bound and aviation converted. I know there is nothing fundamentally wrong with them - it's just my personal problem. A purpose built head and a tweaked version of the Force One hub would go a long way toward making me feel comfortable enough.
 

Geraldc

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Nov 12, 2011
Messages
407
Location
nz
I think it needs to be an inflatable airplane but with normal covering and inflatable ribs spars longerons and fuselage rings.
 
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