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IF the mains are forward of the C of G it's a taildragger.. The attitude it sat on the ground. used to "resemble' the stalled angle but with flaps and ground effect that doesn't always happen. Once it's sitting on 3 wheels it won't porpoise. You can hold the stick right back,the attitude is fixed and you can steer on the tailwheel. Nev

 

 

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Hi Doug,

 

Would we assume that your series of questions are aimed at avoiding getting a tailwheel endorsement when the Thruster is ready for you to fly it?

 

If so, it really doesn't matter what name you give to the landing gear, it'll still have the CG behind the mains/centre of resistance while rolling down the runway, so it'll still prefer to switch ends and depart the runway sideways unless you prevent it from doing that.

 

With that in mind, it's very unlikely that someone will successfully takeoff and land a taildragger without training, not very often anyway ...

 

 

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HaHa, HinC, no, you'd be perfectly wrong. If one did try that. the tail wheel would have to be soo close to the mains it would be impossible to steer at high speed. Whilst on that subject, why is the Thruster inclined to "go anywhere but straight ahead"

 

For what it's worth, at this stage, I'm toying with a new design.

 

 

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Things that make planes want to go off course on take off or landing. Particularly as it applies to tailwheel equipped planes.

 

(1) locating the mains too far forward.

 

(2) poorly set up tailwheel Castor and steering.

 

(3) Engine thrust not offset or large torque or gyroscopic effect.

 

(4) Fin and rudder small or ineffective Needs tail strake or longer fuselage etc

 

(5) insufficient back elevator to get tailwheel on ground when landing..

 

These are the common ailment (faults) Nev

 

 

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Why is the Thruster family a bit touchy on ground handling ?

 

Well the issue is primarily one of wheels too far forward of the cofg so once it starts to wiggle it wags really strongly.

 

The bigger two seaters are worse than the Single seaters and the reasons are:

 

1. For construction simplicity the springs come straight off the bottom of the Aframe and for simplicity that frame is in the plane of the leading edge.

 

2. The two seaters have higher Aframes and longer spring legs - higher ground angle and also moves the cofg on the ground even further rearward of the mains

 

1. And 2. Mean it’s set up to swing easily into a ground loop

 

Add in 3. The fact that the main legs are springs with absolutely zero damping and they are long. The wiggles start easily with this leg setup and are compounded by the undercarriage geometry.

 

So basically you probably couldn’t design a worse/more susceptible to ground loop undercarriage without a lot of effort !!!

 

Having said that I did a few flights in a t500 two weeks ago and the grin is still with me so go figure - love the Thruster and just get a good training in it for its behaviours.

 

How would a better solution look on a Thruster ? - have the main legs closer to the cofg - move the Aframe backward and use v struts to front and back spars. Change the legs from steel springs to be like the UK t600 that uses a tripod leg setup with rubber in compression for suspension

 

But then again - it wouldn’t be a Thruster and you’d have access issues for pilots if you move the a frame back

 

 

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Tony Hayes was working on a riggers angle of incidence mod. when he left us. I think he knew a lot about them. You don't want a plane to be too intimidating. The gusts and winds rabbit holes and runway bumps will challenge you enough, if you fly enough. The thruster was my very first U/L in 1986 . Nev

 

 

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Things that make planes want to go off course on take off or landing. Particularly as it applies to tailwheel equipped planes.(1) locating the mains too far forward.

(2) poorly set up tailwheel Castor and steering.

 

(3) Engine thrust not offset or large torque or gyroscopic effect.

 

(4) Fin and rudder small or ineffective Needs tail strake or longer fuselage etc

 

(5) insufficient back elevator to get tailwheel on ground when landing..

 

These are the common ailment (faults) Nev

(6) alignment if main wheels; toe out for taildraggers

 

 

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Why is the Thruster family a bit touchy on ground handling ?Well the issue is primarily one of wheels too far forward of the cofg so once it starts to wiggle it wags really strongly.

 

The bigger two seaters are worse than the Single seaters and the reasons are:

 

1. For construction simplicity the springs come straight off the bottom of the Aframe and for simplicity that frame is in the plane of the leading edge.

 

2. The two seaters have higher Aframes and longer spring legs - higher ground angle and also moves the cofg on the ground even further rearward of the mains

 

1. And 2. Mean it’s set up to swing easily into a ground loop

 

Add in 3. The fact that the main legs are springs with absolutely zero damping and they are long. The wiggles start easily with this leg setup and are compounded by the undercarriage geometry.

 

So basically you probably couldn’t design a worse/more susceptible to ground loop undercarriage without a lot of effort !!!

 

Having said that I did a few flights in a t500 two weeks ago and the grin is still with me so go figure - love the Thruster and just get a good training in it for its behaviours.

 

How would a better solution look on a Thruster ? - have the main legs closer to the cofg - move the Aframe backward and use v struts to front and back spars. Change the legs from steel springs to be like the UK t600 that uses a tripod leg setup with rubber in compression for suspension

 

But then again - it wouldn’t be a Thruster and you’d have access issues for pilots if you move the a frame back

Look at a cessna 180 or Drifter side on it's the same as a Thruster, I have never experienced the Thruster difficulties that people speak of.

 

 

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Look at a cessna 180 or Drifter side on it's the same as a Thruster, I have never experienced the Thruster difficulties that people speak of.

If you like i'll add an item 2.5 to the list ... the ground angle of the thruster is more than both of the aircraft you list - particularly the drifter ... and a couple of degrees additional ground angle pushes the cofg further behind the main wheels than either of these aircraft ... add item 2.75 that the latteral stiffness of the Thruster tailwheel mount is MUCH lower than then the other aircraft as well ... making tailwheel wiggle all the more likely

So really the thruster is not an easy plane to fly compared to other tailwheel aircraft ... but its still a lovely plane and would be on my top 5 favorites

 

 

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The only time I had a problem with a Thruster in over 500 landings was the time I tried a wheeler landing.

 

As far as Tony Hayes goes, he thought he knew everything about them, but I preferred to do things my way. He used to say you couldn't 3 point a Thruster.

 

 

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Ive flown all of the thrusters other than T600 tailwheel and all of them can be three pointed ...HOWEVER in the T300 and T500 you are right on the edge of the stall angle so IF you get it wrong it is not pleasant.

 

I prefer to glide approach and wheel land them all ... but can do tail low and three point as well depending on how i'm feeling :-P

 

 

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Toe out?When I made R/C models - all taildraggers - it was always slight toe-in.

My Babe was all over the place. I discovered the wheels pointed slightly inwards, so I swapped the u/c legs and now they point slightly apart. Landing it on tar is now a doddle, even in a crosswind.

 

 

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I based my toe-out on discussions I found on flying forums. It seemed to make a difference, although I can't discount slight improvements in pilot skill.

 

My take on it Marty, is that if the tail swings to the left, the left wheel steers slightly left and the right wheel, pointing across the line of travel, produces drag, tending to pull the aircraft back into line.

 

If toed in, the left wheel would dig in and aggravate the swing.

 

 

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I based my toe-out on discussions I found on flying forums. It seemed to make a difference, although I can't discount slight improvements in pilot skill.My take on it Marty, is that if the tail swings to the left, the left wheel steers slightly left and the right wheel, pointing across the line of travel, produces drag, tending to pull the aircraft back into line.

If toed in, the left wheel would dig in and aggravate the swing.

Hold on... if the tail swung to the left, yes I agree the left wheel steers slightly left which helps - but the right wheel exerting drag would exacerbate the swing rather than pulling the aircraft back into line, wouldn't it?

 

If the tail is swinging to the left, then the nose is going right. Adding drag on the right wheel is only going to make the nose go further right, which pulls the tail further left. Same principle as turning the aircraft with differential braking.

 

Sorry OK - just trying to understand this. Not saying you're incorrect, trying to get my head around it.

 

 

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IF the mains are forward of the C of G it's a taildragger.. The attitude it sat on the ground. .....snip..... . Nev

I’m not sure that’s true.

 

The Sokol pictured earlier clearly must have the c of g behind the mains otherwise it would be sitting bum up, nose down, prop kissing the tarmac. But seems everyone has been happy to say its not a taildragger.

 

 

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S

 

I'm also having a hard time explaining my concept of how toe-out helps keep a tail dragger straight...but it seems to work.

I was of the understanding that it improves things for crosswinds. For example a left wing low (take off or landing- wing down into wind) you need right rudder so that with toe out, the left wheel will be tracking straight(ish).

 

 

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I’m not sure that’s true.The Sokol pictured earlier clearly must have the c of g behind the mains otherwise it would be sitting bum up, nose down, prop kissing the tarmac. But seems everyone has been happy to say its not a taildragger.

Do you reckon then that you could put Joe Average Cessna driver in it then and they would handle it ok?

 

 

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I was of the understanding that it improves things for crosswinds. For example a left wing low (take off or landing- wing down into wind) you need right rudder so that with toe out, the left wheel will be tracking straight(ish).

That makes more sense.

 

 

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Jaba- who. What they marketed it as is anyone's guess. They may have claimed it overcame "some" tailwheel problems. I have flown one , when they were new and it was a demonstrator and I have a friend who still has one. I started flying on tailfdraggers so It was no deal.. You just had to be careful you didn't land with the tail too low and put to much weight on the "rear " wheel. A mustang is not much different. and quite a few warbirds. I'll still stick to my definition happily. Where are the "everyone's" who say it's not a taildragger. Taildragger is a colloquial term any how. It's where the mains are that matters. Nev

 

 

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