Will circular runways ever take off?

[[email protected]]

I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?

I supposed the banked sides of this concept help.

BBC story "Will circular runways ever take off?"
http://www.bbc.com/news/magazine-39284294

http://www.endlessrunway-project.eu/project/index.php

SAE paper Flight Operations on a Circular Runway
http://papers.sae.org/660283/
Abstract:
Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.


Chris

[Matt Herron Jr.]

Hmm...interesting idea. first blush thoughts:

headwind changes to a crosswind, changes to a tailwind as you land/take-off?

banked runway means lateral load on the aircraft changes as speed increases, meaning you are slipping or crabbing on the ground?

turning take-off requires higher AOA to produce higher lift in turn? more chance of stall?

Americans don't know haw to drive in a round-about!

the real reason it won't work: drinks slide off the table in 1st class as you taxi to the "threshold".

[Bruce Hoult]

On Thursday, March 16, 2017 at 9:18:32 PM UTC+3, wrote:
> I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?
>
> I supposed the banked sides of this concept help.
>
> BBC story "Will circular runways ever take off?"
> http://www.bbc.com/news/magazine-39284294
>
> http://www.endlessrunway-project.eu/project/index.php
>
> SAE paper Flight Operations on a Circular Runway
> http://papers.sae.org/660283/
> Abstract:
> Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.

It's a interesting idea. Would be a very nice solution if a heavily loaded aircraft could do one or two circuits if necessary before lifting off. Helicopters sometimes do this in ground effect inside the boundaries of a field or clearing to get sufficient sped to climb away.

But 3.5 km diameter!! 2400 acres (970 ha) inside the centre line! That's huge. Only the world's biggest airports have a runway longer than 3.5 km, and very few would have runways that long in different directions.

Maybe you could do this to increase the capacity of LAX or LHR or Kingsford Smith, but for most cities it's a vast increase in the area of an airport, and decrease in the flexibility of siting it around hills or suburbs or bodies of water.

2 km diameter or less and you might be talking -- that's exactly half a G lateral acceleration at 250 km/h (1.12 G total loading)

[Bruce Hoult]

On Friday, March 17, 2017 at 12:16:31 AM UTC+3, Matt Herron Jr. wrote:
> Hmm...interesting idea. first blush thoughts:
>
> headwind changes to a crosswind, changes to a tailwind as you land/take-off?
>
> banked runway means lateral load on the aircraft changes as speed increases, meaning you are slipping or crabbing on the ground?

Smoothly increasing bank on the runway so you can start on flat ground at the start of the takeoff and go up the sides as the speed increases, keeping crab at zero.

> turning take-off requires higher AOA to produce higher lift in turn? more chance of stall?

Not a lot.

At his suggested size of 3.5 km diameter, total G loading at 250 km/h would be 1.04 G, requiring a 2% higher takeoff speed and a 16 degree banking to be balanced.

At 2 km diameter those figures would be 1.12 G, 6% higher takeoff speed, and 27 degrees of bank.

At a very sporting 1 km diameter the figures would be 1.4 G, 20% higher takeoff speed, and 45 degrees banking.

OK, those all assume a constant 250 km/h, so actually it would be worse than that once you allow for the extra loading of the higher speed.

The suggested 3.5 km diameter is certainly very mild! Just almost impossible to find a site for.

[Bruce Hoult]

On Friday, March 17, 2017 at 12:44:54 AM UTC+3, Bruce Hoult wrote:
> On Friday, March 17, 2017 at 12:16:31 AM UTC+3, Matt Herron Jr. wrote:
> > Hmm...interesting idea. first blush thoughts:
> >
> > headwind changes to a crosswind, changes to a tailwind as you land/take-off?
> >
> > banked runway means lateral load on the aircraft changes as speed increases, meaning you are slipping or crabbing on the ground?
>
> Smoothly increasing bank on the runway so you can start on flat ground at the start of the takeoff and go up the sides as the speed increases, keeping crab at zero.
>
> > turning take-off requires higher AOA to produce higher lift in turn? more chance of stall?
>
> Not a lot.
>
> At his suggested size of 3.5 km diameter, total G loading at 250 km/h would be 1.04 G, requiring a 2% higher takeoff speed and a 16 degree banking to be balanced.
>
> At 2 km diameter those figures would be 1.12 G, 6% higher takeoff speed, and 27 degrees of bank.
>
> At a very sporting 1 km diameter the figures would be 1.4 G, 20% higher takeoff speed, and 45 degrees banking.
>
> OK, those all assume a constant 250 km/h, so actually it would be worse than that once you allow for the extra loading of the higher speed.
>
> The suggested 3.5 km diameter is certainly very mild! Just almost impossible to find a site for.

Updated figures, allowing for increased takeoff speed feeding back into G loading and required bank angle..

Assumed straight runway takeoff speed 70 m/s, 252 km/h, 136 knots, 156.5 mph

3500 m diameter, 257 km/h, 1.044 G, 16.6 deg bank
2000 m diameter, 271 km/h, 1.155 G, 30.0 deg bank
1609 m diameter, 285 km/h, 1.276 G, 38.4 deg bank
1414 m diameter, 300 km/h, 1.414 G, 45.0 deg bank
1155 m diameter, 356 km/h, 2.000 G, 60.0 deg bank

The figures head to infinite speed and G at 1000 m diameter.

[son_of_flubber]

On Thursday, March 16, 2017 at 2:18:32 PM UTC-4, wrote:
> has anyone ever tried landing on a curved flat road

I hear that if you need to landout in a field that slopes left to right, you drop the right wingtip a bit during a curving final and then you hold the bank during the curving roll out. The bank keeps the uphill wing tip off the ground until you're stopped.

I've never done it, but the fella that told me this claims that this is the best way to landout in one of our 'better' neighborhood landout fields, and that 'lots of people' have done it in that particular field. As I understand it, you set it up so that at touchdown, you're rolling somewhat uphill and simultaneously across the slope, and you try to stop rolling before you start to roll down hill. I've walked the field and tried to visualize the pattern and the roll out, and it kinda makes sense provided you can also thread your way between a couple of big trees on the leading edge of the field.

[[email protected]]

Circular runways were tested extensively by NACA in the 50's and 60's. General consensus was that, with training and practice, they worked well but were unforgiving with overshooting or undershooting your final approach.

[[email protected]]

Just like with U-line control airplanes! Mine was a P-51D with a Cox 0.049...

Sure made this pilot (more of a crasher) dizzy!

[WB]

On Thursday, March 16, 2017 at 7:38:03 PM UTC-5, son_of_flubber wrote:
> On Thursday, March 16, 2017 at 2:18:32 PM UTC-4, wrote:
> > has anyone ever tried landing on a curved flat road
>
> I hear that if you need to landout in a field that slopes left to right, you drop the right wingtip a bit during a curving final and then you hold the bank during the curving roll out. The bank keeps the uphill wing tip off the ground until you're stopped.
>
> I've never done it, but the fella that told me this claims that this is the best way to landout in one of our 'better' neighborhood landout fields, and that 'lots of people' have done it in that particular field. As I understand it, you set it up so that at touchdown, you're rolling somewhat uphill and simultaneously across the slope, and you try to stop rolling before you start to roll down hill. I've walked the field and tried to visualize the pattern and the roll out, and it kinda makes sense provided you can also thread your way between a couple of big trees on the leading edge of the field.


My very first landout was like that. Landing in a nice long field that had a pronounce slope (except the slope was right to left). Landed diagonally going up the slope, left wing down with some opposite rudder to keep the nose headed uphill. And, yes, the glider did start rollng back down the hill and wheel brake would not hold it. Frantic activity for a second or two as I "bailed out" to stop the glider before it built up speed going backward. Luckily, the glider rolled into a slight hollow that slowed us down while I scrambled out.

[Josh Fletcher]

Its a cute concept... But no one has discussed Instrument approaches.

I don't see any aircraft that could do a CAT III Circle approach to auto land while trying to make a banking turn on a sloped runway. Much less a pilot that could shoot a hard IFR approach to mins in windy conditions and then try to transition to a curving and sloping runway.

Then the issue with Takeoffs. The presenter was saying that they could launch 3 aircraft at the same time on one circle runway..... I call BS.... they will never clear 3 aircraft to TO off the same runway at the same time... What happens if someone aborts the TO? What happens if someone has an engine failure/fire at V1 and can not fly the published. Even with multiple parallel runways, ATC does not launch simultaneous departures just for that reason.

I could go on and on about the issues that would need to be addressed that they so conveniently don't talk about... I am sure many of them would be the same issues that caused NASA to drop the project in the 60's

thats my 2 cents
J


BTW... Under VFR... I routinely landed in a circle my Aviat Husky in a field that was to short for straight in landings and takeoffs... so I don't hate the idea, just don't think its practical. Especially for some of todays pilots that have no stick and rudder skills and rely on the automation entirely to much..

[OHM Ω http://aviation.derosaweb.net]

On Friday, March 17, 2017 at 11:32:16 AM UTC-5, wrote:
> Just like with U-line control airplanes! Mine was a P-51D with a Cox 0.049...
>
> Sure made this pilot (more of a crasher) dizzy!

Cox 0.049. Piffle! Flew CL in the 60's with a Fox 0.35. He-man stuff. I cannot tell you how many mixture adjustment screws I broke moving the control the wrong way while inverted. Oops.

[Bruce Hoult]

On Sunday, March 19, 2017 at 6:07:48 AM UTC+3, OHM Ω http://aviation.derosaweb.net wrote:
> On Friday, March 17, 2017 at 11:32:16 AM UTC-5, wrote:
> > Just like with U-line control airplanes! Mine was a P-51D with a Cox 0.049...
> >
> > Sure made this pilot (more of a crasher) dizzy!
>
> Cox 0.049. Piffle! Flew CL in the 60's with a Fox 0.35. He-man stuff. I cannot tell you how many mixture adjustment screws I broke moving the control the wrong way while inverted. Oops.

I have no idea what it was that I had as a 10 or 11 year old in '73 or '74. But the story is maybe interesting :-)

I went to school in a small village (Hikurangi). For some reason I was in the newsagent near the school when I noticed a boxed but clearly opened model plane on the shelf. I asked about it and was told that it had been sold twice, but neither buyer had been able to make it run, and it had been returned. I said "I bet I can make it go" and was told "If you can make it go you can have it -- take the engine now and bring it back tomorrow".

Challenge accepted.

I don't remember anything about the plane except it was control line and the engine was a "diesel" (i.e. pure compression ignition, no glow plug to start it) and rather incongruously called a "Merlin" which I knew even then was the name of the engine in a Spitfire.

So a quick google turns up:

http://www.modelenginenews.org/cardfile/merlin.html
http://www.modelenginenews.org/cardfile/images/merlins.jpg

And that's definitely it. Mine must have been the "Super Merlin" as it had the plastic fuel tank bolted to the back of the engine.

0.75 cc. I didn't know that then. I guess that's 0.046 in the lingo you guys are talking.

I don't know what the previous customers had been doing, because it took me less than five minutes to get it running, even starting from absolutely zero knowledge about model aircraft engines (though I was already experienced with 2 stroke lawnmowers and chainsaws and motorcycles).

Got to love the modern internet...

https://www.youtube.com/watch?v=WykvN6vYEiU

I reckon I got it going easier than this guy does! And I didn't have any bench mount .. I just held it by the fuel tank with my spare hand.

So, I took it back to the shop, demonstrated that I could get it going, and the owner gave me the model plane that went with it.

My brother and I had a few hours fun playing with it with nothing serious happening. Until our father asked to try it. "I did a couple of hours in a Harvard when I was in Cadets in 57". Right. Well .. he got about two turns around the circle, then it was straight up, straight down at full power (no choice about that), and a plane smashed to smithereens.

And that was the end of that.

[Martin Gregorie[_5_]]

On Sun, 19 Mar 2017 04:28:57 -0700, Bruce Hoult wrote:

> And that's definitely it. Mine must have been the "Super Merlin" as it
> had the plastic fuel tank bolted to the back of the engine.
>
Nice one. When I wur a lad most of the engines we had were diesels, but
were the older Mills 0.75 and the Milles 1.3 (ccs of course) and mostlyt
went on the front Keilkraft Phantom Mites and Phantoms respectively, easy
to fly and made from sheet balsa.

> 0.75 cc. I didn't know that then. I guess that's 0.046 in the lingo you
> guys are talking.
>
An .049 engine is just under 0.8cc. Americans have innumerable
competition classes. all based around engine capacity in both 'U-
control' (control line) and free flight, so just as the most popular
engines were the Cox PeeWee and TeeDee .049s, there was also a Cox
TeeDee .051 so you could fly a model in one class with a TD 049 on it,
then replace that with a TD 051 and fly it in the next class up.

TeeDees were the motors to have until Leroy Cox lost his shirt when the
slot car craze imploded, his fantastic machine tools wore out and the
engines got progressively worse. TeeDes were machined from bar stock to
such good tolerances that breaking a new motor in involved bolting it
onto the model, giving it 30 seconds of rich 4-stroke running and then
leaning it out and letting it scream.

> I don't know what the previous customers had been doing, because it took
> me less than five minutes to get it running, even starting from
> absolutely zero knowledge about model aircraft engines (though I was
> already experienced with 2 stroke lawnmowers and chainsaws and
> motorcycles).
>
> Got to love the modern internet...
>
> https://www.youtube.com/watch?v=WykvN6vYEiU
>
Easiest engine to start I ever had was an ED Racer (2.46cc diesel). I
bolted it to the bench, filled the tank, quick squirt in the ports and
flicked it over slowly to get some lube on the bearings - and it started
with that first flick.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bruce Hoult]

On Sunday, March 19, 2017 at 4:49:07 PM UTC+3, Martin Gregorie wrote:
> On Sun, 19 Mar 2017 04:28:57 -0700, Bruce Hoult wrote:
>
> > And that's definitely it. Mine must have been the "Super Merlin" as it
> > had the plastic fuel tank bolted to the back of the engine.
> >
> Nice one. When I wur a lad most of the engines we had were diesels, but
> were the older Mills 0.75 and the Milles 1.3 (ccs of course) and mostlyt
> went on the front Keilkraft Phantom Mites and Phantoms respectively, easy
> to fly and made from sheet balsa.
>
> > 0.75 cc. I didn't know that then. I guess that's 0.046 in the lingo you
> > guys are talking.
> >
> An .049 engine is just under 0.8cc. Americans have innumerable
> competition classes. all based around engine capacity in both 'U-
> control' (control line) and free flight, so just as the most popular
> engines were the Cox PeeWee and TeeDee .049s, there was also a Cox
> TeeDee .051 so you could fly a model in one class with a TD 049 on it,
> then replace that with a TD 051 and fly it in the next class up.
>
> TeeDees were the motors to have until Leroy Cox lost his shirt when the
> slot car craze imploded, his fantastic machine tools wore out and the
> engines got progressively worse. TeeDes were machined from bar stock to
> such good tolerances that breaking a new motor in involved bolting it
> onto the model, giving it 30 seconds of rich 4-stroke running and then
> leaning it out and letting it scream.
>
> > I don't know what the previous customers had been doing, because it took
> > me less than five minutes to get it running, even starting from
> > absolutely zero knowledge about model aircraft engines (though I was
> > already experienced with 2 stroke lawnmowers and chainsaws and
> > motorcycles).
> >
> > Got to love the modern internet...
> >
> > https://www.youtube.com/watch?v=WykvN6vYEiU
> >
> Easiest engine to start I ever had was an ED Racer (2.46cc diesel). I
> bolted it to the bench, filled the tank, quick squirt in the ports and
> flicked it over slowly to get some lube on the bearings - and it started
> with that first flick.

Young folks now with their LIPOs and ESCs and digital proportional control and digital response curves and control mixing and trim and and and ... don't know what they're missing.

Oh to be a kid now! Well, a kid with money, anyway. I never had that either.

[Dan Marotta]

Bruce,

Your story made me smile, especially the full power vertical "landing".
Been there, done that...

Cheers,
Dan

On 3/19/2017 5:28 AM, Bruce Hoult wrote:
> On Sunday, March 19, 2017 at 6:07:48 AM UTC+3, OHM Ω http://aviation.derosaweb.net wrote:
>> On Friday, March 17, 2017 at 11:32:16 AM UTC-5, wrote:
>>> Just like with U-line control airplanes! Mine was a P-51D with a Cox 0.049...
>>>
>>> Sure made this pilot (more of a crasher) dizzy!
>> Cox 0.049. Piffle! Flew CL in the 60's with a Fox 0.35. He-man stuff. I cannot tell you how many mixture adjustment screws I broke moving the control the wrong way while inverted. Oops.
> I have no idea what it was that I had as a 10 or 11 year old in '73 or '74. But the story is maybe interesting :-)
>
> I went to school in a small village (Hikurangi). For some reason I was in the newsagent near the school when I noticed a boxed but clearly opened model plane on the shelf. I asked about it and was told that it had been sold twice, but neither buyer had been able to make it run, and it had been returned. I said "I bet I can make it go" and was told "If you can make it go you can have it -- take the engine now and bring it back tomorrow".
>
> Challenge accepted.
>
> I don't remember anything about the plane except it was control line and the engine was a "diesel" (i.e. pure compression ignition, no glow plug to start it) and rather incongruously called a "Merlin" which I knew even then was the name of the engine in a Spitfire.
>
> So a quick google turns up:
>
> http://www.modelenginenews.org/cardfile/merlin.html
> http://www.modelenginenews.org/cardfile/images/merlins.jpg
>
> And that's definitely it. Mine must have been the "Super Merlin" as it had the plastic fuel tank bolted to the back of the engine.
>
> 0.75 cc. I didn't know that then. I guess that's 0.046 in the lingo you guys are talking.
>
> I don't know what the previous customers had been doing, because it took me less than five minutes to get it running, even starting from absolutely zero knowledge about model aircraft engines (though I was already experienced with 2 stroke lawnmowers and chainsaws and motorcycles).
>
> Got to love the modern internet...
>
> https://www.youtube.com/watch?v=WykvN6vYEiU
>
> I reckon I got it going easier than this guy does! And I didn't have any bench mount .. I just held it by the fuel tank with my spare hand.
>
> So, I took it back to the shop, demonstrated that I could get it going, and the owner gave me the model plane that went with it.
>
> My brother and I had a few hours fun playing with it with nothing serious happening. Until our father asked to try it. "I did a couple of hours in a Harvard when I was in Cadets in 57". Right. Well .. he got about two turns around the circle, then it was straight up, straight down at full power (no choice about that), and a plane smashed to smithereens.
>
> And that was the end of that.

--
Dan, 5J

[Dan Marotta]

I don't think being a kid these days would equip one with the rich
experiences we had. Imagine carrying a knife to school! When I was a
kid, every boy had a jack knife in his pocket. Some days, at recess, it
would be fun to just whittle on a stick. Funny thing, nobody ever got
stabbed or cut. Imagine having easy access to mercury. What fun it was
to play with! Did you ever run with scissors? Ride a bicycle or horse
without a helmet? Drive 120 mph with no seat belts in the car? Kids
these days have no idea how much they missed! But they do get trophies
just for showing up... My Dad taught me to shoot when I was 8 or 10
years old. Now that I'm 69, I still haven't shot any body. Imagine
that. Maybe I could even now get a world record with or without an
engine (a motor is electric)...

On 3/19/2017 8:11 AM, Bruce Hoult wrote:
> On Sunday, March 19, 2017 at 4:49:07 PM UTC+3, Martin Gregorie wrote:
>> On Sun, 19 Mar 2017 04:28:57 -0700, Bruce Hoult wrote:
>>
>>> And that's definitely it. Mine must have been the "Super Merlin" as it
>>> had the plastic fuel tank bolted to the back of the engine.
>>>
>> Nice one. When I wur a lad most of the engines we had were diesels, but
>> were the older Mills 0.75 and the Milles 1.3 (ccs of course) and mostlyt
>> went on the front Keilkraft Phantom Mites and Phantoms respectively, easy
>> to fly and made from sheet balsa.
>>
>>> 0.75 cc. I didn't know that then. I guess that's 0.046 in the lingo you
>>> guys are talking.
>>>
>> An .049 engine is just under 0.8cc. Americans have innumerable
>> competition classes. all based around engine capacity in both 'U-
>> control' (control line) and free flight, so just as the most popular
>> engines were the Cox PeeWee and TeeDee .049s, there was also a Cox
>> TeeDee .051 so you could fly a model in one class with a TD 049 on it,
>> then replace that with a TD 051 and fly it in the next class up.
>>
>> TeeDees were the motors to have until Leroy Cox lost his shirt when the
>> slot car craze imploded, his fantastic machine tools wore out and the
>> engines got progressively worse. TeeDes were machined from bar stock to
>> such good tolerances that breaking a new motor in involved bolting it
>> onto the model, giving it 30 seconds of rich 4-stroke running and then
>> leaning it out and letting it scream.
>>
>>> I don't know what the previous customers had been doing, because it took
>>> me less than five minutes to get it running, even starting from
>>> absolutely zero knowledge about model aircraft engines (though I was
>>> already experienced with 2 stroke lawnmowers and chainsaws and
>>> motorcycles).
>>>
>>> Got to love the modern internet...
>>>
>>> https://www.youtube.com/watch?v=WykvN6vYEiU
>>>
>> Easiest engine to start I ever had was an ED Racer (2.46cc diesel). I
>> bolted it to the bench, filled the tank, quick squirt in the ports and
>> flicked it over slowly to get some lube on the bearings - and it started
>> with that first flick.
> Young folks now with their LIPOs and ESCs and digital proportional control and digital response curves and control mixing and trim and and and ... don't know what they're missing.
>
> Oh to be a kid now! Well, a kid with money, anyway. I never had that either.

--
Dan, 5J

[Gert Bass]

>Its a cute concept... But no one has discussed Instrument approaches.
>

I'd like to see that discussed, too. But I see enormouse safety
potential there - as it is basically an endless runway.

We only need the tight vertical and lateral guidance for precision
approaches BECAUSE of a defined TD point and limited runway length. As
long as you can fly a nice DME arc around that tower you don't even need
vertical guidance as long as you descend slow enough - sooner or later
you will see the runway - and even if you don't you would touch down
maybe a little hard but on the "start" of the runway with all the
distance in the world to remain. Laterally you should still be rather
precise, but then again not really, because if you aren't lined up
perfectly just keep that arc going, correct a bit and you are dead
centerline.

This requires a completely different viewpoint. I would say it
practically eliminates the need for a go-around - because why would you?

I don't see the advantage for wind really, but that's not a big issue in
the first place.

[[email protected]]

On Thursday, March 16, 2017 at 11:18:32 AM UTC-7, wrote:
> I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?
>
> I supposed the banked sides of this concept help.
>
> BBC story "Will circular runways ever take off?"
> http://www.bbc.com/news/magazine-39284294
>
> http://www.endlessrunway-project.eu/project/index.php
>
> SAE paper Flight Operations on a Circular Runway
> http://papers.sae.org/660283/
> Abstract:
> Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.
>
>
> Chris

This might be a good idea for auto towing. We have 2800 ft of straight runway at our gliderport. At 780 ft field elevation with a tow vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL auto towing a 2-33 with two people in it. Except for the problem of the wind causing a portion of the circle to be towing the glider downwind, a circular runway would seem to be a good way to extend the runway length indefinitely, and get more altitude for a given rope length.

[Steve Leonard[_2_]]

On Wednesday, March 22, 2017 at 12:24:42 PM UTC-5, wrote:

> This might be a good idea for auto towing. We have 2800 ft of straight runway at our gliderport. At 780 ft field elevation with a tow vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL auto towing a 2-33 with two people in it. Except for the problem of the wind causing a portion of the circle to be towing the glider downwind, a circular runway would seem to be a good way to extend the runway length indefinitely, and get more altitude for a given rope length.

I am envisioning the NTSB report now...

[Frank Whiteley]

On Wednesday, March 22, 2017 at 11:24:42 AM UTC-6, wrote:
> On Thursday, March 16, 2017 at 11:18:32 AM UTC-7, wrote:
> > I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?
> >
> > I supposed the banked sides of this concept help.
> >
> > BBC story "Will circular runways ever take off?"
> > http://www.bbc.com/news/magazine-39284294
> >
> > http://www.endlessrunway-project.eu/project/index.php
> >
> > SAE paper Flight Operations on a Circular Runway
> > http://papers.sae.org/660283/
> > Abstract:
> > Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.
> >
> >
> > Chris
>
> This might be a good idea for auto towing. We have 2800 ft of straight runway at our gliderport. At 780 ft field elevation with a tow vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL auto towing a 2-33 with two people in it. Except for the problem of the wind causing a portion of the circle to be towing the glider downwind, a circular runway would seem to be a good way to extend the runway length indefinitely, and get more altitude for a given rope length.

Reverse pulley is what you need.
http://www.coloradosoaring.org/thinking_pages/ground_launching/reverse_pulley/default.htm

[JS]

On Wednesday, March 22, 2017 at 4:53:51 PM UTC-7, Frank Whiteley wrote:
> On Wednesday, March 22, 2017 at 11:24:42 AM UTC-6, wrote:
> > On Thursday, March 16, 2017 at 11:18:32 AM UTC-7, wrote:
> > > I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?
> > >
> > > I supposed the banked sides of this concept help.
> > >
> > > BBC story "Will circular runways ever take off?"
> > > http://www.bbc.com/news/magazine-39284294
> > >
> > > http://www.endlessrunway-project.eu/project/index.php
> > >
> > > SAE paper Flight Operations on a Circular Runway
> > > http://papers.sae.org/660283/
> > > Abstract:
> > > Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.
> > >
> > >
> > > Chris
> >
> > This might be a good idea for auto towing. We have 2800 ft of straight runway at our gliderport. At 780 ft field elevation with a tow vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL auto towing a 2-33 with two people in it. Except for the problem of the wind causing a portion of the circle to be towing the glider downwind, a circular runway would seem to be a good way to extend the runway length indefinitely, and get more altitude for a given rope length.
>
> Reverse pulley is what you need.
> http://www.coloradosoaring.org/thinking_pages/ground_launching/reverse_pulley/default.htm

Isn't the circular runway standard float plane technique on small lakes?
Jim

[Gert Bass]

>> > This might be a good idea for auto towing. We have 2800 ft of
straight runway at our gliderport. At 780 ft field elevation with a tow
vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a
maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL
auto towing a 2-33 with two people in it. Except for the problem of the
wind causing a portion of the circle to be towing the glider downwind, a
circular runway would seem to be a good way to extend the runway length
indefinitely, and get more altitude for a given rope length.
>>

This can actually be done on any normal glider field in the form of
towing up an down the runway. The towcar doesn't have a very big turning
radius, so no need for even a large (wide) field. And the glider is
already in the air when the towcar reaches the end of the field and can
make a much larger turn - kind of a teardrop reversal. The towcar can
also slow down a lot for the turn because the glider slingshots around
it. Like a waterskier who overtakes the boat turning.

This can be done several times back and forth and if the tow cable can
be lengthened/reeled out it could reach much higher altitudes than with
a winch launch. But it's rather crazy and a bit like below - better one
good straight setup unless you have a really loong field.
Of course very safe on a circular track if available ;)


>Isn't the circular runway standard float plane technique on small lakes?

Yea theoretically it is always discussed and for helos in confined areas
as well. In practice I find it doesn't work.
When do you need it? When you are loaded heavy. That means you use full
power to barely start climbing. The turning actually does use up that
little extra power every time I experimented with it - because you bank
quite a bit as space is tight. So setting up the departure in the
longest straight line possible has always been just as good if not
better and looks a lot more sane ;)
Now, turning slightly into wind or to go over the lowest trees that are
off the straight departure is standard, but is far from spiralling

[[email protected]]

On Thursday, March 23, 2017 at 11:31:26 PM UTC-7, Gert Bass wrote:
> >> > This might be a good idea for auto towing. We have 2800 ft of
> straight runway at our gliderport. At 780 ft field elevation with a tow
> vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a
> maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL
> auto towing a 2-33 with two people in it. Except for the problem of the
> wind causing a portion of the circle to be towing the glider downwind, a
> circular runway would seem to be a good way to extend the runway length
> indefinitely, and get more altitude for a given rope length.
> >>
>
> This can actually be done on any normal glider field in the form of
> towing up an down the runway. The towcar doesn't have a very big turning
> radius, so no need for even a large (wide) field. And the glider is
> already in the air when the towcar reaches the end of the field and can
> make a much larger turn - kind of a teardrop reversal. The towcar can
> also slow down a lot for the turn because the glider slingshots around
> it. Like a waterskier who overtakes the boat turning.
>
> This can be done several times back and forth and if the tow cable can
> be lengthened/reeled out it could reach much higher altitudes than with
> a winch launch. But it's rather crazy and a bit like below - better one
> good straight setup unless you have a really loong field.
> Of course very safe on a circular track if available ;)

Regarding the up and down the runway multiple pass auto tow, with the turn around at the runway ends: Have you actually done it, or do you know anyone who has?

Our runway is dirt and is quite wide, at least 200 ft. so a turn around might be possible without slowing the tow car too much. We also have two shorter, narrower runways that meet together and also with the main runway ends, forming a triangle. Not an equilateral triangle, but fairly close to it. I'm wondering if this triangular circuit could be used to make multiple laps around the circuit on auto tow. One thing I thought of is that instead of a payout winch to let out more line, you could just start out with more line laid out in the first place in order to get higher. However, the trade - off with that idea would seem to be that the tow car would be further down the runway at the start of the tow, so the glider would not get as high by the end of the first runway run as you would with less line out at the beginning of a one leg straight auto tow. So the glider would have to make the first turn around(s) at lower altitude that can be reached with one straight run. Hopefully with each pass, you could eventually get higher than the single pass run. We found by trial and error that about 1100 ft of rope seems to work out for the highest auto tows in still air on our 2800 ft. runway on one pass straight ahead auto tows with our 1-26 and 2-33. We have also towed a DG-100 using the same length rope and tow vehicle. The DG was able to get about 150 ft higher than the 1-26, probably due to better, aerodynamic efficiency.

>
>
> >Isn't the circular runway standard float plane technique on small lakes?
>
> Yea theoretically it is always discussed and for helos in confined areas
> as well. In practice I find it doesn't work.
> When do you need it? When you are loaded heavy. That means you use full
> power to barely start climbing. The turning actually does use up that
> little extra power every time I experimented with it - because you bank
> quite a bit as space is tight. So setting up the departure in the
> longest straight line possible has always been just as good if not
> better and looks a lot more sane ;)
> Now, turning slightly into wind or to go over the lowest trees that are
> off the straight departure is standard, but is far from spiralling

Not a float plane pilot, but I read somewhere that float planes also taxi around on the water in different directions when it's glassy in order to make wakes that allow the floats to break the surface tension on take off and get the plane airborne easier?

[[email protected]]

On Wednesday, March 22, 2017 at 4:53:51 PM UTC-7, Frank Whiteley wrote:
> On Wednesday, March 22, 2017 at 11:24:42 AM UTC-6, wrote:
> > On Thursday, March 16, 2017 at 11:18:32 AM UTC-7, wrote:
> > > I saw this story and it reminded me, has anyone ever tried landing on a curved flat road or something similar to a circular runway?
> > >
> > > I supposed the banked sides of this concept help.
> > >
> > > BBC story "Will circular runways ever take off?"
> > > http://www.bbc.com/news/magazine-39284294
> > >
> > > http://www.endlessrunway-project.eu/project/index.php
> > >
> > > SAE paper Flight Operations on a Circular Runway
> > > http://papers.sae.org/660283/
> > > Abstract:
> > > Inherent advantages of an infinitely long runway, optimum technical location at the center of the circle, and safety enhancement by increased directional stability during aircraft ground roll generated interest in the circular runway concept. The Bureau of Naval Weapons originated a project to determine, within the realm of aircraft behavior, the feasibility of flight operations from a circular runway.Utilizing an existing circular track at the General Motors Proving Ground near Mesa, Arizona, tests were conducted with a T28, an A1-E, an A4-B, and a C54. It was determined that pilots readily adapt to operations from a circular runway, that aircraft lateral and directional stability is more positive than on a flat runway, that tangential approaches are no more difficult than approaches to a straight runway, and that low visibility approaches are much simpler than to a straight runway. Flight operations from a circular runway are feasible.
> > >
> > >
> > > Chris
> >
> > This might be a good idea for auto towing. We have 2800 ft of straight runway at our gliderport. At 780 ft field elevation with a tow vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL auto towing a 2-33 with two people in it. Except for the problem of the wind causing a portion of the circle to be towing the glider downwind, a circular runway would seem to be a good way to extend the runway length indefinitely, and get more altitude for a given rope length.
>
> Reverse pulley is what you need.
> http://www.coloradosoaring.org/thinking_pages/ground_launching/reverse_pulley/default.htm

Thanks for the link. It looks like another interesting approach!

[[email protected]]

Here is another interesting variation on the theme. Hang glider pilots have utilized the "step tow" method to gain higher altitudes when using a pay-out winch. Here is an example: https://www.youtube.com/watch?v=q1d0Jc-EfJ8

RC

[[email protected]]

On Sunday, March 26, 2017 at 12:19:25 AM UTC-4, wrote:
> On Thursday, March 23, 2017 at 11:31:26 PM UTC-7, Gert Bass wrote:
> > >> > This might be a good idea for auto towing. We have 2800 ft of
> > straight runway at our gliderport. At 780 ft field elevation with a tow
> > vehicle like a V-8 Chevy Suburban or a V-8 pickup truck, we can get a
> > maximum of about 800ft AGL auto towing a 1-26, and maybe 475ft AGL
> > auto towing a 2-33 with two people in it. Except for the problem of the
> > wind causing a portion of the circle to be towing the glider downwind, a
> > circular runway would seem to be a good way to extend the runway length
> > indefinitely, and get more altitude for a given rope length.
> > >>
> >
> > This can actually be done on any normal glider field in the form of
> > towing up an down the runway. The towcar doesn't have a very big turning
> > radius, so no need for even a large (wide) field. And the glider is
> > already in the air when the towcar reaches the end of the field and can
> > make a much larger turn - kind of a teardrop reversal. The towcar can
> > also slow down a lot for the turn because the glider slingshots around
> > it. Like a waterskier who overtakes the boat turning.
> >
> > This can be done several times back and forth and if the tow cable can
> > be lengthened/reeled out it could reach much higher altitudes than with
> > a winch launch. But it's rather crazy and a bit like below - better one
> > good straight setup unless you have a really loong field.
> > Of course very safe on a circular track if available ;)
>
> Regarding the up and down the runway multiple pass auto tow, with the turn around at the runway ends: Have you actually done it, or do you know anyone who has?
>
> Our runway is dirt and is quite wide, at least 200 ft. so a turn around might be possible without slowing the tow car too much. We also have two shorter, narrower runways that meet together and also with the main runway ends, forming a triangle. Not an equilateral triangle, but fairly close to it. I'm wondering if this triangular circuit could be used to make multiple laps around the circuit on auto tow. One thing I thought of is that instead of a payout winch to let out more line, you could just start out with more line laid out in the first place in order to get higher. However, the trade - off with that idea would seem to be that the tow car would be further down the runway at the start of the tow, so the glider would not get as high by the end of the first runway run as you would with less line out at the beginning of a one leg straight auto tow. So the glider would have to make the first turn around(s) at lower altitude that can be reached with one straight run. Hopefully with each pass, you could eventually get higher than the single pass run. We found by trial and error that about 1100 ft of rope seems to work out for the highest auto tows in still air on our 2800 ft. runway on one pass straight ahead auto tows with our 1-26 and 2-33. We have also towed a DG-100 using the same length rope and tow vehicle. The DG was able to get about 150 ft higher than the 1-26, probably due to better, aerodynamic efficiency.
>
> >
> >
> > >Isn't the circular runway standard float plane technique on small lakes?
> >
> > Yea theoretically it is always discussed and for helos in confined areas
> > as well. In practice I find it doesn't work.
> > When do you need it? When you are loaded heavy. That means you use full
> > power to barely start climbing. The turning actually does use up that
> > little extra power every time I experimented with it - because you bank
> > quite a bit as space is tight. So setting up the departure in the
> > longest straight line possible has always been just as good if not
> > better and looks a lot more sane ;)
> > Now, turning slightly into wind or to go over the lowest trees that are
> > off the straight departure is standard, but is far from spiralling
>
> Not a float plane pilot, but I read somewhere that float planes also taxi around on the water in different directions when it's glassy in order to make wakes that allow the floats to break the surface tension on take off and get the plane airborne easier?

The historical evidence, i.e. back issues of Soaring Magazine, indicate that death of the pilot is the reason the practice of reversing an auto tow is not recommended nor endorsed. You have to go back to the '30's and 40's but there are graphic warnings in the letters to the editor. I learned on a winch in the '70's and even the practice of "kiting out the wire" is fraught with potential disruptions and anomalies. Entanglement of the aircraft is probably the chief bugaboo, and I might hazard a guess that with the lighter weight high-strength lines available now, it will be an even greater risk.. 1/8 inch steel has a lot less aerodynamic potential than the "spectra" used for its high tow potential.
Two of my dear friends (both having been instructors and nationally rated pilots), aerotowing a 2-33 in the 80's related how in turbulence the tug surged forward then slowed enough that the rope came back in a loop, wound around the wing and they were only able to extricate themselves by "ruddering" out of the loop a moment before it snapped shut.The rope/wire glider combination has to be kept straight at all times.

[[email protected]]

No

[[email protected]]

A curved runway idea!!! What a LAUGH!!

Posted by an email name "Green Eggs and Ham"



Do you like
Curved runways to land?

I do not like them,
Sam-I-am.
I do not like
Curved runways to land!

Would you like them
Here or there?

I would not like them
here or there.
I would not like them
anywhere.

[Bret Hess]

I can still remember how mercury feels in the