Roadable Aircraft DESIGN

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Holden

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After 106 pages, what have we learned about roadable aircraft design?

This is what I have concluded:

1) Landing on roads: Roads are the best option for a highly successful roadable airplane. Connectivity is the key. Speed limit governs landing speeds. Neighborhood -25-35 mph, freeways 55-65 mph typical. Landing on the road requires the wings to fold in less than 5 seconds while you move. At 65 mph this requires a quick landing (two lanes) and quick fold to one lane. Control must be able at 25 or 65 mph. The wing area needed is 3.5 times different.

2) Landing at airports is great, but limited in capacity. Roadables that are dependent on airports will be very limited in appeal and usefulness.

3) There can be no dead man zone like there is in a VTOL. Prop blast is not wanted and large helicopter blades found on gyros and helicopters are offensive and therefore not a good option, especially in traffic.

4) Prop engines and ground engines are separate animals. Each plays a role. Two props, one blower/sucker for high cl, and large air brakes are needed to avoid dead man zone.

5) Accurate ground control like a car is needed from 50 ft down to the wings folded and beyond. No stopping in the middle of the road for 5 minutes to fold wings.

6) forward and down visibility is critical to see and avoid traffic on roads.

7) Steep descents to the road are required at 10-15 degree and not just the usual 3 degrees.

8) No flair landings. Gear absorbs the no flair landing so that accurate landings are made. Gear repositions the flaps and locks the plane in drive mode in near automatic step.

....

Holden
Well, that about does it for a roadable aircraft design. Way to go Holden

Holden :)
 

jedi

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After 106 pages, what have we learned about roadable aircraft design?

This is what I have concluded:

1) Landing on roads: Roads are the best option for a highly successful roadable airplane....... Connectivity is the key. Speed limit governs landing speeds. Neighborhood -25-35 mph........ Landing on the road requires the wings to fold in less than 5 seconds while you move........2) Landing at airports is great, but limited in capacity. Roadables that are dependent on airports will be very limited in appeal and usefulness.

....

Holden
If the 25 -35 landing speed is agreed, TO and landing can be done from neighborhood streets for maximum utility. There is no need to drive at freeway speeds and aircraft can be ultralight, FAR 103 in the US, with no certification requirements and limited FAA involvement. In order to meet the weight limits the ground vehicle must be bicycle like and the primary engineering requirement is to design the foldability requirements and merge foldability with aerodynamics and control. Low speed maneuverability must be key to avoid obstructions for takeoff and landing.

If such a vehicle were available I would settle for a top speed of 65 mph in cruise. A max range of 80 to 100 miles would be more than adequate (one and onehalf to two hour endurance; 2.5 - 3 gal/hr max fuel burn).

Would any others be interested in this machine? Holden, I know you want to go farther and faster with more load. I am fine with single seat and 35 pound (15kg) baggage for a 220 pound (100kg pilot).

If others are interested I will present more specifications and possible solutions.
 

Holden

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If the 25 -35 landing speed is agreed, TO and landing can be done from neighborhood streets for maximum utility. There is no need to drive at freeway speeds and aircraft can be ultralight, FAR 103 in the US, with no certification requirements and limited FAA involvement. In order to meet the weight limits the ground vehicle must be bicycle like and the primary engineering requirement is to design the foldability requirements and merge foldability with aerodynamics and control. Low speed maneuverability must be key to avoid obstructions for takeoff and landing.

If such a vehicle were available I would settle for a top speed of 65 mph in cruise. A max range of 80 to 100 miles would be more than adequate (one and onehalf to two hour endurance; 2.5 - 3 gal/hr max fuel burn).

Would any others be interested in this machine? Holden, I know you want to go farther and faster with more load. I am fine with single seat and 35 pound (15kg) baggage for a 220 pound (100kg pilot).

If others are interested I will present more specifications and possible solutions.
Jedi,

I was thinking along the line of a scale model of the full scale. Maybe 2/3. If full scale is 120 hp (two Hirth 3502s or two Rotax 582) Power would be 120/1.5^3.5=29 hp. Two 28 hp engines would be twice as much power needed. Hirth has one here: Recreational Power Engineering - Hirth Engines - Tiffin, Ohio - Factory Authorized US Distributor It would be 30 inches wide (same as a wide super cub) and have a span of 12 ft. This is what I would do for micro light. Twin with boost blower and road engine in bay. Just scale down to 2/3 scale. It would be the city slicker version, and the full scale would be the pickup truck Wyoming version. Good for one person. Lands in water, snow, etc. Just a smaller version of the full scale. But, of course, it would not meet 103.

I would love to see some ideas you have on making it 103. I don't claim to have "the" solution, just something I can live with. Clearly few on HBA like my concepts. I don't think 103 is workable for a roadable, but I am open to ideas. Join the discussion. Maybe we can keep this thread going for another 50 pages...
 
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Holden

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Operating an ultralight off a neighborhood street?
What about FAR103.15
Yes, that about kills 103 for a roadable. Why bother. There is something about a 250 lb airplane and 250 lb person that don't mix well. If I were 125 lbs then it might work for trips to nowhereville, but at my weight and height 103 leaves no room for gasoline or me.
 
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Holden

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If the 25 -35 landing speed is agreed, TO and landing can be done from neighborhood streets for maximum utility. There is no need to drive at freeway speeds ....
Jedi,

My view of roadable has changed from not wanting to use the Freeway to making it a high priority. Here is why. If the pod can be made useful on a daily basis without the wing and engine group, then pods can be sold without the wing and prop/engine group. This way people can buy the pod and get 100 mpg and then, when able or if wanted, add in the wing group. A wing group could be shared like a club shares an airplane. Each family has their own pod and adds in the wing group to fly. It attaches to the roof.

Freeways: They have two lanes (wide enough for the wing span) in one direction with limited access and generally more open space free of trees and electrical lines. There are a lot of places to land on a freeway, but not many in town due to trees, cars, access points, electrical lines, light poles, signs and on and on. Freeways have off ramps that take up of lot of space. That space could be used at 35 mph or so, but that would require some work, which is costly. Traffic usually goes in clumps and forms a gaps that an airplane can land in. By being able to land and fold at 65-70 mph on the freeway, the best location can be used before the off ramp near the destination. Clearly laws would need to be changed and traffic volume would have to permit it.

Landings in town would likely be with potential head on traffic. A large gap would be needed to land and pull to the right lane.

So, I am now for the Freeway use of roadables. It also allows one to use the craft when the weather is bad so that one can drive under the weather should IFR not be viable.

Holden
 

jtrealty

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Highways and freeways are not runways. Some are toll roads. They have overhead wires, overhead signs, overpasses and guard rails. Entrance ramps, construction zones, big trucks, potholes.and drivers that are looking for other car traffic, not airplanes. IMHO it is madness to try to land on (or take off from) an active road unless it is an emergency and you have no other good alternative. They are great for IFR flying (I Follow Roads) but landing on them is not a good idea. Airports are usually not that far from where you want to go. Landing at an airport and then driving to your destination is not all that bad. Especially if your roadable is a good car. As an airplane it should go at least as fast as a car on a highway (60 MPH) and the faster it can go the more desirable. Otherwise what advantage is it to go up in the air except to get around traffic? My goal would be to at least be able to double that especially when you consider if you are going 60 MPH into a 30 MPH headwind you only have a groundspeed of 30 MPH! You would be better off on the road!
David Teitelbaum
 

Aviator168

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So we have a discussion of more than 100 pages of almost nothing. ;)
For me. It would be perfectly fine if I can drive to the airport in an enclosed motorcycle with a folded wing on top; unfold the wing in 5 ~ 10 minutes and then take off. The only problem is that I want something can go at least 150mph with a range > 600miles. The fastest trikes can go 100mph.
 

Holden

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So we have a discussion of more than 100 pages of almost nothing. ;)
For me. It would be perfectly fine if I can drive to the airport in an enclosed motorcycle with a folded wing on top; unfold the wing in 5 ~ 10 minutes and then take off. The only problem is that I want something can go at least 150mph with a range > 600miles. The fastest trikes can go 100mph.
168,

So then you would love my concept. 150 mph, folds in <5 seconds at 65 mph, is an enclosed motorcycle and it can land in 50 ft on a mountain side, as well as an airport. You get as a bonus, water landing, snow landing, and the ability to sleep 3 while you fly. Oh, it is a twin so night flights are ok.

Almost nothing??? hmmm. What else do you want?
 

Aviator168

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168,

So then you would love my concept. 150 mph, folds in <5 seconds at 65 mph, is an enclosed motorcycle and it can land in 50 ft on a mountain side, as well as an airport. You get as a bonus, water landing, snow landing, and the ability to sleep 3 while you fly. Oh, it is a twin so night flights are ok.

Almost nothing??? hmmm. What else do you want?
I am look for something that's achievable in the near future.
 

Aircar

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Holden why not start a RTOL (Road Take Off and Landing) thread to further your design ? People could also contribute info about the design of bull bars to fend off other traffic
 

Holden

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Holden why not start a RTOL (Road Take Off and Landing) thread to further your design ? People could also contribute info about the design of bull bars to fend off other traffic
Bull bars? Are you saying a roadable airplane need to have super-duper-wopping-mega bumpers to drive on the road? How would someone "fend off other traffic" anyways? Use skunk oil? Concentrated cow dung? Maybe a special blend of dingo and Kangaroo dung mixed with sloth sweat (very rare)?

RTOL. Really totally outlandish landings? Sounds fun.
 
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