learning tractors

[WHY]

Having watched the many post about design and characteristics of the tractor gyro it is clear that those of us who are interested in the tractor certainly have a lot of extra "learning" to do, especially in the ground handling department and in the take off and landing department of the tractor.

I can remember when I began my fixed wing instruction, I had a "old" instructor ( about my age now) who was very firm about the fact that I should learn to first fly a "taildragger" type plane and then move on to the trii-gear. His opinion was that if you learned the taildragger first then you could easily learn about any tri-gear. He didn't mention that there were many different types of taildraggers and how they each seemed to have there own special quirks, for instance my first taildragger was a Aeronca 7-AC, probably the easist taildragger to learn in especially with the newer Scott tail wheel.

Once I learned this aircraft I thought I had done pretty good, then tried a Piper PA-11, it was like I didn't know anything about tailwheel planes but eventually got good at this aircraft, then tried a Taylor craft L2-M with the small hard rubber tail wheel, again it was like I had never been in a taildragger and never did get the hang of the L2-M.

Now comes the tractor gyro with the tailwheel and a completely different nature to it, in the fixed wing craft the first thing was always to "get the tail up" and then all the touchy handling disappeared, now with the taildragger gyro it would seem the the most desired take off and landing method is the "three point" lift off " and the tail first or "three point" touch down".

While some taildragger time in a fixed wing is certainly going to be of some help, it is obvious that the "exact" nature of the taildragger gyro is going to be distinct and special and require special consideration in training.

Tony

[John Stahl]

Tony
I have come to the conclusion that a tractor gyro in a tail dragger configuration will never catch on for two reasons. First there is no training available in a tail dragging gyro. All the training that is available is in tricycle gear pushers.
The second I believe that no mater how well designed the tail dragging gyro is the rotor is got too much control and will tend to make the tail dragging gyro want to ground loop.

For a tractor to catch on it will have to be a tricycle gear Configuration then there is no problem getting training and the rotor management in not as critical.

John

[TractorFan1407]

Hello all, I need your assistance if possible, I am building a website all about tractor videos, to date I have gathered 386 different farming tractor brands and I hope to document every agricultural tractor make and model ever made. I am especially looking for videos and pictures of rare oldt imer tractors, such as Farmhall, McCormick International or Minneapolis-Moline. I can be contacted at the following email address admin (at) youtractor.com. Any content you provide will remain your property and you will be credited with it.

I look forward to hearing from you

Patrick Malloney

[TractorFan1407]

Hi, anybody able to help?

[John Stahl]

http://www.youtube.com/watch?v=Xfh8InsLxWA

http://www.youtube.com/watch?v=On_mY-DpeAw&feature=related

http://www.youtube.com/watch?v=dWhViFYEFJY&feature=related

http://www.youtube.com/watch?v=_EFt7cLCRSY&NR=1

http://www.youtube.com/watch?v=eHsyVab3LoM&feature=related

http://www.youtube.com/watch?v=PbalOh4smnM&feature=related

http://www.youtube.com/watch?v=Y4MwxHCzGbY&feature=related


As you can see tractor on this forum has nothing to do with farming.
Tractor here means that the engine pulls the gyro through the air.
A pusher gyro pushes the gyro through the air. Here are a few examples of a pusher gyro.

http://www.youtube.com/watch?v=s1-Fo7uQlrY&feature=related

http://www.youtube.com/watch?v=cq7tG-vk050&feature=related

http://www.youtube.com/watch?v=cfBpQix1P1Y&feature=related

http://www.youtube.com/watch?v=MBhkvZlPrWk&feature=related

[gyromike]

Hi, anybody able to help?

Did you even look to see what this Forum is about?

[Alan_Cheatham]

For those who criticize the tail dragger tractor gyro get the Littlewing video from Ron Heron. When comparing the ground handling characteristics to a typical tricycle gear gyro the Littlewings are much more graceful and don't appear to have any problems, especially at the low speeds they take off and land at.

There is an advantage in having a tail dragger configuration on a tractor gyro in that unlike an airplane which can accelerate to it's take off speed and then "rotate" it's wing into a higher angle to lift-off a gyro needs to have it's rotor tilted back during the take off roll in order to accelerate the rotor to flying speed, and the tail dragger configuration allows greater rotor-to-tail clearances during this phase of operation.

[brett s]

The second I believe that no mater how well designed the tail dragging gyro is the rotor is got too much control and will tend to make the tail dragging gyro want to ground loop.

A ground loop is from not having enough control authority to stop the yaw rate once started, not from having too much.

More control via the rotor should be a good thing here, just use it properly! Sure, bad pilot technique will always bite...

[DennisFetters]

What I posted on tractor gyros some time ago may help with understanding some other characteristics to look out for;


Small Tractor vs Small pusher Gyro
03-30-2007, 01:12 PM
Those that forget history are doomed to repeat it. No truer words were ever spoken.

Tractor Gyroplanes still have the same problems they have always had. Just do a little history study and learn.

Tractor gyros are fun to fly, and fly reasonably well.

Tail dragger gyros, tractor or not, have the same problems that any tail dragger aircraft will have.... unstable on the ground and wants to switch ends. Sure, fly them, there fun, just easer to make a mistake.

The real problem with a tractor is "P" factor of the propeller. Gyroplanes are famous for slow and low flight, just where you can get in trouble with a tractor and can't recover.

As an example, you are flying by your friends low and flow, fat dumb and happy. At this point, the airflow to the propeller is entering at an angle, and this means one side of your propeller has a bigger bit of air, which creates more thrust on one side of the propeller,which creates a yaw to the gyro.

This is OK, the pilot is holding enough rudder in to counteract the yaw. But then he decides to give an input with the rudder to yaw the nose to impress his friend, and BAM!! The gyro violently yaws to one side and begins a spin, and the pilot has no rudder control even with full power, and augers into the ground!

What happened? The rudder left the slipstream of the propeller thrust and didn't have enough airflow to counteract the p-factor of the propeller, and as the gyro spun, the rudder could not reenter the slip stream.

Solution? have enough altitude to reduce the power, regain forward gliding airspeed, and resume powered flight. Also design your tractor with a center H tail, so the outer rudders will catch the slipstream in this case.


Thank you for your thoughts Dennis,

Would you please help me understand why the P factor would be greater in a tractor?

I was not able to find reports of Tractor Autogiros spinning in the thirties and forties. There was a lot of talk about them being spin and stall proof. Where would I find reports of accidents in that era?

I’m sorry; I am not able to imagine your example. Why is it that the spin could not be countered? What was the forward airspeed in your example?

Thank you, Vance


03-30-2007, 03:36 PM
Sure.
P-factor is not greater on a tractor verses a pusher, it is about the same. The advantage of the pusher is that the rudder is only one or two foot behind the propeller, so you always have authority over P-factor.

A tractors rudder can me 10 foot or much more away from the propeller. If you are at slow airspeed, where you are relying on the propeller wash to counteract the P-factor, then your rudder must stay in the wash to retain authority. If you abruptly yaw the aircraft, it is possible to remove the rudder from the prop wash, because there is a delay due to the distance between the prop and the rudder and the time it takes for the wash to reach the rudder. Due to this delay, the rudder would stay ahead of the prop wash in the spin.

The term spin proof and stall proof is being used to compare the gyro to an airplane, and it's true, a Gyroplane will not stall of spin, for the same reasons an airplane would. As you know, when an airplane stalls or spins, it was due to a loss of lift.

In the case where a tractor Gyroplane, it will not stall, per say, nor will it spin for the same reason as an airplane would. But, Gyroplanes, as you have seen, will spin without stalling.

In the case example I have given earlier, it is the P-factor that pulls the tractor Gyroplane in a spin.

[John Stahl]

When you are taking off and you do not make a three point take off. When your tail comes off the ground if your rotor is not level the rotor can pull your gyro into a ground loop.

I believe that rotor management is very critical during take off.

The older gyros all had winglets or tabs on there Horizontal stabilizer. Do I understand correctly, they were there to help prevent spins? The more I learn the more I realize how smart the early gyro designers were.

Why the dorsal fins?? I have an idea but I would like others to give me there theories

[DennisFetters]

The older gyros all had winglets or tabs on there Horizontal stabilizer. Do I understand correctly, they were there to help prevent spins? The more I learn the more I realize how smart the early gyro designers were.

Why the dorsal fins?? I have an idea but I would like others to give me there theories

Yes, like I posted above.

The dorsal fins on the wingtips were to prevent "adverse roll with yaw". As you added rudder and turned the nose, the wing and body would tent to be drug down, so the turned up tips would make the advancing wing tip stay up, while the lagging wing tip would push down, keeping the wings level.

[Passin' Thru]

Did you even look to see what this Forum is about?

Amazing, isn't it? ;):sad::D

[John Stahl]

The dorsal fin I am talking about is on the top and bottom of the fuselage

[brett s]

One reason is probably to simply get more vertical stab area - you're always limited in height because of blade clearance.

[chuter]

I put my lower vertical fin on to accomplish some of what a tall tail does on a pusher; catch the swirling prop wash to hopefully cancel out some of the yaw from the wash hitting just the top vertical surface.

[DennisFetters]

The dorsal fin I am talking about is on the top and bottom of the fuselage

Sorry, I missed the post until now.

It does the same thing. In a yaw, the dorsal fins help twist the tail to counteract adverse roll with yaw.

[DennisFetters]

I put my lower vertical fin on to accomplish some of what a tall tail does on a pusher; catch the swirling prop wash to hopefully cancel out some of the yaw from the wash hitting just the top vertical surface.

To accomplish any torque cancellation, the surface of the empennage must be in close approximation to the propeller.

In this case of a tractor, the vertical stabilizer would be too far back from the propeller. As the prop-wash travels back, it cones down in diameter due to the accelerated air causing a low pressure area and being crushed into a smaller diameter by the slower surrounding air. As this occurs, the swirling air off the prop begins to straighten out somewhat, having less swirl and in a much smalled diameter, therefor loosing much of the ability to use the stabilizer to counteract torque that far back.

[chuter]

In this case of a tractor, the vertical stabilizer would be too far back from the propeller. As the prop-wash travels back, it cones down in diameter due to the accelerated air causing a low pressure area and being crushed into a smaller diameter by the slower surrounding air. As this occurs, the swirling air off the prop begins to straighten out somewhat, having less swirl and in a much smalled diameter, therefor loosing much of the ability to use the stabilizer to counteract torque that far back.


Maybe so, but I did a rag-on-a-stick-with-the-gyro-tied-down test and found that just in front of the tail the airflow was one way above the fuselage and the other way below the fuselage.

It may not be enough to make much difference but there was an obvious change in direction from top to bottom.

[DennisFetters]

Maybe so, but I did a rag-on-a-stick-with-the-gyro-tied-down test and found that just in front of the tail the airflow was one way above the fuselage and the other way below the fuselage.

It may not be enough to make much difference but there was an obvious change in direction from top to bottom.

I agree, and did the same test. There will still be some swirl, but it will not be enough to make much of a difference.

[TractorFan1407]

Sorry I just thought that people might have been interested.

[kolibri282]

What about a Porsche (Ferrari red) or a two wheel?....;-)

PS: pictures taken last weekend at a local festival.

[C. Beaty]

Stop it! Or I’ll post a picture of my 1960 Martha Furgeson (I know it’s Massy but I prefer Martha).

[RotoPlane]

Oh yeah....well I may do the same for a 1955 Ford-Furgeson diesel...if I still had them. Loved that little tractor....

[kolibri282]

(I know it’s Massy but I prefer Martha).
Of course! Tractors must be female, just like ships.

By the way, do you have that one for tow tests with your new XXL gyro, Chuck?

[C. Beaty]

By the way, do you have that one for tow tests with your new XXL gyro, Chuck?Nope. Just for mowing weeds and keeping the county Weed Inspector off my back.

[PalmPilot]

The tractor-pullers are kind of cool, and I agree, ships should be a she... :)

With regard to Tractor Gyro's, since there are so few, this is good information and helps people better understand them.... Thanks Dennis, great explanation!

Mike

[Jean Claude]

The real problem with a tractor is "P" factor of the propeller. Gyroplanes are famous for slow and low flight, just where you can get in trouble with a tractor and can't recover.
Dennis, It seems to me that the "P" factor is proportional to the forward speed. For a gyroplane, thrust asymmetry should not exceed 1/2 inch. A slight shift of angle of the engine can probably compensate the yaw torque (by blowing on the tail).

To accomplish any torque cancellation, the surface of the empennage must be in close approximation to the propeller.
In this case of a tractor, the vertical stabilizer would be too far back from the propeller. As the prop-wash travels back, it cones down in diameter due to the accelerated air .
In my opinion, is the opposite: Since more far from propeller, the airflow is more accelerated, and a VS or HS should be more effective.
As this occurs, the swirling air off the prop begins to straighten out somewhat, having less swirl and in a much smalled diameter .
The conservation of angular momentum says that when the radius decreases, the angular velocity increases. Then, the V.S efficience to conter the torque should be the same. (It seems to me)
Jean Claude

[C. Beaty]

The Cierva C-30 used an inverted airfoil on one half of the tailplane for torque compensation.

Ron Heron has mentioned that for his LittleWing, the main wheels were placed on scales and tailplane differential incidence was adjusted for equal weights with engine running at cruise power. I’m not sure this gives correct torque balance in flight but it’s a start.

Contraction of the propeller slipstream is in accordance with Bernoulli. Pour syrup out of a bottle and the stream contracts as it is accelerated by gravity. Has nothing to do with the surrounding air.