Turf Glide Tundra tires on AR-1

Abid

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Large Turf Glide Tundra Tires option on AR-1. ($2000.00 at time of order or $2900 retrofit). Perfect if you fly from grass strips more than from tarmac runways. Softer pressure and wider grip for soft field operations and adds almost 2.5 inches of further travel on mains.
 

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Abid

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Did you make the front tire larger too?

No but it can be done with little effort. It will make getting in and out a little harder because it will raise the height in front seat.
In a soft field scenario, you really want to get the front wheel light as soon as possible ideally on takeoff and keep it off as long as possible on landing. So having a smaller diameter tire in front and larger diameter on mains allows even more rock back which allows the front wheel to come up earlier. It will get your gyro off at slower speed but it won't be ready to fly. The pilot will have to keep it near ground and build speed to Vx before allowing it to climb. Technique matters otherwise with a cranked keel that allows a good pilot to utilize more soft fields, also allows bad pilots to prang it in falling behind power curve on takeoff climb. Those pilots should not be doing soft field stuff anyway. This is one reason Magni does straight keel I have heard to save you from yourself. But it restricts good pilots from utilizing full range. Different ideas for different folks I guess.
 
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Abid

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Can you explain what this means, please?

The tire is taller than standard tire and literally the first thing that travels when you drop the gyro down is the tire and then the landing gear. In effect it allows an extra 2.5" of travel in suspension. Standard AR-1 had about 3 inches of suspension travel in 7075-T6 leaf spring and tire would smash down only after that because standard tire runs at around 45 psi. Now its close to 5.5 inches and tire goes first because it is at 12 psi.
 

Resasi

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More so for taxiing and the first stage of a take off.
That certainly seems the conventional wisdom with soft/rough/long grass ops. Though as I have just posted, even though the Wagtail Trojan's main wheels are much larger than the nose wheel it handle pretty rough terrain very well.
 
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DavePA11

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In all my soft field flying it's the front tyre that dictates how capable the machine is off airport.
More so for taxiing and the first stage of a take off.

wolfy
I agree. Had one landing in my SC M912 up a grass hill before rain at night and the landing was near zero forward speed, but since steep incline the front tire contacted the grass sooner than normal. Well under the grass it was mud so came to a quick stop using all of the front suspension. If the tire was bigger I expect would have been less likely to dig in as much.

It really got my heart pumping on that landing and with almost zero forward speed, can’t imagine what would happen if the front tire dug into the surface or went into a gopher hole on take off speeds. I have landed in grass airstrips that did have gopher holes along the taxi way, but had my 29” tires on my Cub. Several non bush nose wheel planes with small tires taxied within inches of these holes before I was able to tell them. Almost caused a prop strike. This was in upstate New York in private strip along river…owner recently passed. He had a covered bridge to get to the island with grass strip. He didn’t seem to care about the non bush planes.. :)
 

Abid

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In all my soft field flying it's the front tyre that dictates how capable the machine is off airport.
More so for taxiing and the first stage of a take off.

wolfy

Your machine has straight keel or cranked keel? You want that front wheel light as soon as possible. The shorter front wheel allows more rack back angle (angle of the disc) and that allows front wheel to start getting off the ground sooner. Cranked keel is a positive in doing that
 

Abid

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I agree. Had one landing in my SC M912 up a grass hill before rain at night and the landing was near zero forward speed, but since steep incline the front tire contacted the grass sooner than normal. Well under the grass it was mud so came to a quick stop using all of the front suspension. If the tire was bigger I expect would have been less likely to dig in as much.


So about what you just wrote.
Imagine if you had a cranked keel instead of a straight keel. Then also think about if the diameter of the front tire was a bit smaller than mains.
What would that have allowed you to do?

It would allow you to rack up more allowing to keep front wheel from touching the ground longer because well geometry.

In a soft field landing, per PTS you are expected to land softly with power on and not allow front wheel to dig in and instead taxi off with a little speed (keeping power on) and stick back to keep front wheel light. Coming to a full stop in such a situation is not desirable exactly because you can dig in.
I even keep power on and wheelie forward to a better area. You have to have the practice to be able to wheelie with just mains on the ground lightly touching it but that is why soft field serious operations require these practice exercises on a particular model so pilot has got it all down before doing it for real. I can't say I have landed in a uphill steep climbing terrain but those would be my thoughts. Plenty of thunderstorms with rain that makes South Lakeland plenty soft here but its level.
In an tri-gear airplane or a trike (WSC) where there is practically no geometrical stop of a back keel hitting the ground, I can see this logic but in a pusher gyro with keel being the limiting factor, it is different.


D. TASK: SOFT-FIELD APPROACH AND LANDING

REFERENCES: FAA-H-8083-21; Gyroplane Flight Manual.

Objective. To determine that the applicant:

1. Exhibits knowledge of the elements related to a soft-field
approach and landing.
2. Considers the wind conditions, landing surface, and obstacles.
3. Selects a suitable touchdown area.
4. Establishes and maintains a stabilized approach at the
recommended airspeed, with gust correction factor applied, ±5
knots.
5. Establishes and maintains proper ground track with crosswind
correction, as necessary.
6. Makes smooth, timely, and correct control application during
the flare and touchdown.
7. Touches down smoothly, at a minimum forward airspeed with
no appreciable drift, and with the longitudinal axis aligned with
the intended landing path.
8. Maintains sufficient speed to taxi on soft surface.
 
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Abid

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I saw the other post Resasi is talking about and here is that video of the South African gyro that they made for military ops in rough terrain. Notice they have the same idea, even more exaggerated. Cranked keel. Smaller diameter on front wheel and high HP engine.


If the pilot knows what they are doing, they can take advantage tremendously of that cranked keel and smaller diameter front tire. If they don't, then they need to be saved from themselves and yes a bigger front tire could do that to a point and reduce potential capability and also a straight keel can save a pilot from themselves while reducing potential capability. It is a tough call for a designer.
 

Tyger

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I have landed in grass airstrips that did have gopher holes along the taxi way, but had my 29” tires on my Cub. Several non bush nose wheel planes with small tires taxied within inches of these holes before I was able to tell them. Almost caused a prop strike. This was in upstate New York in private strip along river…owner recently passed. He had a covered bridge to get to the island with grass strip. He didn’t seem to care about the non bush planes.. :)
You must be talking about "Island Bob" Ferenczi. I imagine those were woodchuck holes on his island.
I heard they buried him at Saratoga National Cemetery and a bunch of "bush" planes landed at the cemetery in his honor!
 

DavePA11

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Yes Tyger - Island Bobs runway. Ah I’m not sure what a wood chuck is, but have seen the holes it makes! Yes recently passed and bunch of planes were there to honor him. He was nice guy to allow people to land at his place. I found him a bit gruff, but didn’t know him well.

Browns runway in VT is nice place to visit too. Owner is very nice but unique too.
 

wolfy

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Your machine has straight keel or cranked keel? You want that front wheel light as soon as possible. The shorter front wheel allows more rack back angle (angle of the disc) and that allows front wheel to start getting off the ground sooner. Cranked keel is a positive in doing that
My current machine has a straight keel but with just enough height.
I have a powerfull prespinner. With high rotor rpm all thats needed is airspeed over the disk, a flatter disk (within reason) allows faster increase of airspeed. With less of a pre spinner (lets say sub 200) more rock back will help get a rotor up to speed.

I agree a cranked keel will allow more rock back but also,
If your geometry is unchanged and you have just added larger mains your head angle has less rake back and will require more airflow before the front can start to become light, that means more ground speed in light wind conditions. Not ideal in soft field.

I didn't see anything in the trojan video that I would consider soft or overly rough field. Even the pindan (red dirt) strip was slightly rough but it was all hard ground.

Try operating out of course sand river bed islands and sand tracks ect, high ground speeds need to be avoided especially for the front wheel.

Your machine will still be a good thing, just not up to what I call off airport opps. With a say 600x6 or turf glide front tyre it will be a lot closer.

wolfy
 

wolfy

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I also agree Abid with your smaller front once the rotor is up to speed it will be easier to keep it light or off the ground, but on take off naturally you have to get the rotor up to speed first.

wolfy
 

Abid

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My current machine has a straight keel but with just enough height.
I have a powerfull prespinner. With high rotor rpm all thats needed is airspeed over the disk, a flatter disk (within reason) allows faster increase of airspeed. With less of a pre spinner (lets say sub 200) more rock back will help get a rotor up to speed.

I agree a cranked keel will allow more rock back but also,
If your geometry is unchanged and you have just added larger mains your head angle has less rake back and will require more airflow before the front can start to become light, that means more ground speed in light wind conditions. Not ideal in soft field.

I didn't see anything in the trojan video that I would consider soft or overly rough field. Even the pindan (red dirt) strip was slightly rough but it was all hard ground.

Try operating out of course sand river bed islands and sand tracks ect, high ground speeds need to be avoided especially for the front wheel.

Your machine will still be a good thing, just not up to what I call off airport opps. With a say 600x6 or turf glide front tyre it will be a lot closer.

wolfy

Our angle stops are 2 degrees higher than MTO and 4 higher than Magni to begin with towards the back but I have adjustability in the stops that can allow a couple of degrees more.
The increase in height of these larger tires in not much. 1.5 inches. Mainly its the width and area and low pressure.

I could do the front wheel change rather easily if I feel that is needed after testing fully.
 

Tyger

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Yes Tyger - Island Bobs runway. Ah I’m not sure what a wood chuck is, but have seen the holes it makes! Yes recently passed and bunch of planes were there to honor him. He was nice guy to allow people to land at his place. I found him a bit gruff, but didn’t know him well.

Browns runway in VT is nice place to visit too. Owner is very nice but unique too.
I have heard that August (Island Bob's) is still open to visitors this summer, although continued operations are in some doubt...
Are you talking about "Mortimer Brown Landing" (1VT8) NW of Rutland? It wasn't on my radar till you mentioned it.
I met the owner of "Gar Field" (7NY1) yesterday at Schenectady airport. I got invited to visit "any time" :)
I love visiting small grass strips.

PS I found some good pics of Island Bob and his bridge (and of his island after a flood!):
 
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