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Disc Brakes


Guest fly

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Hi to All,

 

Looking for feed back on disc brakes, especially on Thrusters.

 

Any experience with the............. Black Max 1000 set up from Free Bird Aviation,

 

Any info or advice on any other brands or set ups.

 

Differential braking on Thrusters, A plus or minus ??

 

A question for Tony, Please.

 

Can A Thruster tip forward onto it's nose under heavy braking, Tail up, Tail down ????...............thanks ..FLY

 

 

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Guest High Plains Drifter

Fly,

 

if you are putting differential brakes on, it would probably pay to put on a castering tail wheel. I would also recomend toe brakes.

 

Differential brakes allow far more control over your take off and landing ground run.

 

If you are concerned about tipping over I would apply brakes simular to an automotive antilock brake system. To practice - at a fast taxi speed (near flying speed), quickly apply then release the brakes to see the efect. As the feel for the brakes become self evident, you can gradually slow down the taxi/brake practice speeds.

 

HPD

 

 

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Guest TOSGcentral

Yes you can put a Thruster on it’s nose – you can put anything on its nose if you try hard enough. But in the case of the Thruster the machine is very forgiving, has a huge prop clearance and (when instructing on them) allows a lot more latitude for the student to “get it wrong†and therefore learn faster, without too much wear on the instructor’s nerves!

 

However, the most likely time for a nose over is when landing, still tail up and moving quite quickly – then applying brakes.

 

A sense of proportion is essential when looking at brakes on a Thruster. What do you want them for?

 

Personally I believe that they are essential for safety reasons if you are involved with paved surfaces and particularly parking areas because the aircraft often just will not stop and especially so if going down hill and/or down wind.

 

They are also handy to hold the aircraft while doing pre take off checks (especially the mags).

 

But in general operations from grass the rolling resistance is quite adequate to control the aircraft and brakes are not needed.

 

So – my philosophy on brakes is simple. They are normally not needed and anyway should NOT be used at any speed above normal taxiing! They most certainly should NOT be used in any part of the landing until the aircraft is down to normal taxi speed (unless in a dire emergency in which case you better check your own airmanship as to why you put yourself in that position in the first place).

 

Differential Brakes are really just icing on the cake. They can be handy but again are just added complication and very much of an overkill. I have tried them and feel that they just lure you into unwise operation. The Thruster will turn well enough and tightly enough to put excessive repeat force through the tailwheel and ventral fin as it is – without turning it tighter!

 

If your Thruster is not turning well on the ground then you would be better off looking at the tailwheel geometry (which I did an illustrated article on in a recent TOSG Bulletin) and get that geometry right. If you still feel the need to turn tighter then I suggest you examine you operational behaviour with the aircraft and use it in a more planned fashion so that you do not have to turn it so tightly!

 

A couple of words on something HPD has said regarding castoring tailwheels – DON’T!

 

Apart from the legality (unless you want to trot out and get an Engineering Order) they would be lethal on a Thruster! The aircraft is so normally prone to swing and weathercocking the last thing that you require is to reduce tailwheel resistance to the swing or weathercock!

 

Toe brakes are virtually out of the question due to pedal design, routing the control cables and lack of vertical space.

 

Bear in mind that the vast majority of damage to Thrusters is caused reasonably evenly between loss of control in a bounce situation – or – swinging off the runway and hitting something!

 

Aye

 

Tony

 

 

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Guest High Plains Drifter

Fly,

 

Tony is an old codger who has been flying for a long time, and flying Thrusters a long time - I would listen to his advice.

 

My Thruster experiance finnished near twenty years ago, so my recolections of whats do-able in Thusters is a bit rusty.

 

I would query Tony though about how you can stop runway excursions.

 

HPD

 

 

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Guest TOSGcentral

OK – Preventing agricultural excursions, casual unintended sightseeing on the ground – or just basically leaving the runway!

 

The absolute basic is STOP ANY SWING INSTANTLY! Just do not let a swing develop either to the point that the in-built and unstable ground loop couple becomes more powerful than the controls that you have – or – you are going to occupy more space than is available in order to re-sort the direction.

 

Until a pilot has instinctive fine rudder control on a Thruster then over-control can be as much or more of a problem than what you were originally attempting to cure.

 

A simple technique is to use the rudder by “jabbing†or “tapping†the pedals – first jab to stop the swing, second to straighten it up, then a succession of jabs to bring it back into the middle of the runway.

 

Most people attempt to do this in one go, do not get the control off early enough, and then (finding they have the same or a worse problem going the other way) have a mad panic and over-control back again. This the start of the classic Pilot Induced Oscillation that is very much wrapped up with the Scanning/Processing/Controlling sequence employed by the brain and the time lag neatly gets you 180 degrees out of phase with what is going on!

 

The over-control process is an unstable fugoid situation that usually winds up with breaking something! It is more commonly found in a bouncing situation.

 

So – any deviation in direction must be instantly stopped by a light but positive jab on the relevant rudder pedal!

 

A swing is caused by one (or a combination) of three things.

 

  • Engine effects on opening or closing the throttle rapidly and by a large amount. Cure: Stay ahead of the aircraft and consequently use the throttle smoothly – plus – know what the engine effects actually are.
     
     
  • Cross Wind weathercocking the aircraft. Cure: Operate the aircraft only within both its cross wind component limits (15 kts) and your currency competence (which may make even a lightish cross wind too much of a handful for you. Use the wing down technique in conjunction with a wheel landing procedure where you are keeping the fin and rudder up above the wing wake and the aircraft is still under full three axis control at the point of touch down.
     
     
  • Wing drop during a low speed, high amplitude bounce. Cure: Primarily use wheel landing techniques but stay current on three pointers but practice these in ideal conditions just to stay current.
     

 

A short story on the latter point that may make you smile. At Watts Bridge a rather headstrong individual was competing in a fly-in competition and the current bit was spot landings.

 

The T300 arrived in a huge cloud of dust, nearly fully stalled, too high, and dropped a wing in the spectacular bounce that ensued. The judges (as is usual) were lined up like crows on a fence two wing spans from the spot landing point to award points.

 

On the second arrival the T300 swung violently through 90 degrees (virtually in its own length) and headed for the judges. Said judges (who probably had not achieved more than a sedate trot for many years) were suddenly highly motivated to challenge serious sprinting records to avoid being hit by the now totally out of control aircraft!

 

Nobody was hurt but I got a couple of hours work fixing the undercarriage. I did not mind that but it was the second time that day I had done it on that aircraft for the same reason. Some people just do not learn!

 

Note: I have available a couple of manuals that I wrote to tidy up areas of knowledge and skills that are not (in my opinion) treated adequately, or at all, in basic training. They cover all aspects of operating taildraggers and are liberally illustrated.

 

The Students manual costs $35 and the Instructors version costs $42. Both are inclusive of postage and available only directly from myself.

 

Aye

 

Tony

 

 

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It is very hard to put a Thruster on its nose. I nearly did it once by taxying down a steep hill, lost control and shot across the runway to put one wheel in a hole. The tail went up until all I could see was grass, then fell back down again.

 

Of course if you have to land it with the tail up and then apply brakes anything could happen , but why not 3 point it. It isn't too hard and a lot safer than wheeling it on.

 

Others may disagree but I have done several hundred Thruster landings 3 point but only 1 wheeler.

 

 

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re disc brakes

 

Ok I have taken your advice on board and thank you all for time and effort taken to respond to my questions. both long and short,,,,,,,,,,, all appreciated...... HPD,YENN, TOSG.

 

I agree good brakes are a important safety factor on the ground and for run up checks, also far better to be able to stop in a hurry if needed.

 

And brakes of course are needed to stop your wheels spinning after you take off to reduce wheel bearing and tyre wear due to air friction, you don't have to ask your passenger to lean out and grab the tyre , some of them think your joking !

 

Tony I have a copy of your student tail wheel conversion manual,

 

After I read it I thought hard about selling my T500 and returning to the safety of a Bantam,.... but I decided to give the Thruster a go, that's if I ever finish the rebuild! and get it in the air

 

.

 

Wheelersand three pointers ,,,,,,,,, Now thats a point of differing opinons ?

 

I know wheelers look after the air frame, but are three pointers an necessary part of shortfield landings ??

 

A...question

 

Does a Falcon 3 1/8 VSI need an opening in dash panel same as ALT with provision for Adjuster at lower left.

 

Once Again thanks for input...FLY

 

 

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Guest TOSGcentral

VSI Question - self sorting! If it has an adjuster like an adjustable QNH altimeter then obviously you will have to cut a slot for it. Must admit that I have never seen an adjustable VSI before myself though.

 

Your comment about post take-off application of brakes is valid - especially if you fly on the big balloon tyres that go out of balance so quickly and really shake the aircraft up for a minute after take-off.

 

Three point landings v's wheelers is a subject I seem to be regularly drawn back into so I will repeat what I have said previously.

 

Yes you need to be current on 3 point skills as it is the preferred landing in an emergency situation as it does give the shortest and slowest ground roll - so there is less chance of hitting anything (eg in long grass) in a strange area.

 

However, while the wheel on landing is normally harder to do and harder to teach - that is not the case in the Thruster. And that form of landing is far kinder to the airframe while avoiding some of the present control difficulty areas until we have fixed the wing angle of incidence situation.

 

I find that most adherents of the 3 pointer tend to be traditional because they are skilled enough to do them (and generally they do not have to fix aircraft that have been abused after too many 3 pointers that did not go well).

 

Yenn started quoting figures and mine may be of interest. I have done over 9.000 wheel on landings on Thrusters and only a couple of hundred three pointers. That compares with my overall history where the other 16,000 odd landings (on about 150 types total) were three pointers (excepting the nosewheel aircraft of course that I never bothered with much as they bore me to tears).

 

Bottom line is really that we should operate aircraft according to their actual needs rather than our personal preferences.

 

Aye

 

Tony

 

 

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My thruster only uses the small wheels as well and have no brakes at the moment.

 

This is no longer than 50m or so.

 

Was going to fit brakes to mine but thought its just more weight to put on it.

 

 

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Hi Fly, I have black max 1000 brakes, I think their great but a bit pricey. You can get them direct from usa cheaper. Proably made in china anyway. I'ts easy to say thrusters don't need them but I found them important for warm up time, short take offs, taxing the list goes on. The discussion on to wheel it on or three pointer is one of choice but I remember asking my instructor who taught me to wheel it on when would you choose to three pointer and his response was never. I've checked my log and have 520 landings with only half a dozen being three pointers just to say I've done some. My thruster which has good brakes, landing slow can stop in a very short distance. I wouldn't challenge any one but it would be interesting.

 

Regards Terry

 

 

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Re disc brakes

 

Hi Terry,

 

Thanks for info on black max, your right about price, aircraft spruce is the way to go.

 

Did you fit them up ?? How about a pic or two on their adaption to the thruster springs please.

 

Have you also the non return valve used as a hand brake.

 

Wheel it on seems the go ...............FLY

 

 

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Hi Tony, thanks for info as usual.

 

I dont have a VSI as yet, on order. I am cutting in anticipation !

 

I like the vert compass card as opposed to the pedestal above dash type,

 

besides a southern hem version, is a compass a compass . I have seen a few aircraft fitted with both vert and pedestal, Is this necessary for some reason that I am unaware of ? .............. FLY

 

 

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This thread seems to a bit about Thrusters in general. Yenn said that it was hard ti stand a Thruster on its nose. Not so. I landed into fairly stiff headwind on my 200 metre strip (wheeler of course), I turned around and taxyed back to the other end, perhaps a little too fast with the tail wind. I inadvertently put the stick back and the wind got under the elevator and up went the tail. So here I was skating along on the nose, fence coming up fast, what to do? Pull stick back again, quick dab on the throttle got the tail down again, then stood on the right rudder and another dab of the throttle for a controlled ground loop.

 

 

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I have not tried to do a nosestand,but,the point being raised by Yenn is not as black and white as you may think.All that I would like to point out is that on a 582 Thruster Gemini the prop is only centimetres in front of the nose of the pod so you may avoid a propstrike,whereas on a T500 it is maybe 50 or 60cm in front (maybe more?) so it would be nearly impossible to avoid a propstrike if the nose of the pod hit the ground.Just an observation.

 

 

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