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To rack or not to rack

Guest fly

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Hi All,


I have a drawing by D Belton labelled 1/10/85 TST SPRINT , thruster custom built trailer.


What I would like to know, if any one can help.


Are the 2 upright supports, front and rear of trailer which consist of two bays 5 inches wide each and 23 inches deep labelled 2 and 3 in the drawing [ if you have the same as I] desinged to carry the wings racked or assembled? .........does one ever carry assembled wings ?


What are the 2 inch wide scat belt webbing loops for ? to carry wing stays ??


When the wings are racked they are close to 20 feet[ T500] in length, are they transported as such ? or disassembled further { harbour bridge etc ] to reduce length


How much overhang of pod , prop etc is legal out the back?


Any info or advice do's and dont's from previous thruster packing and transport adventures, besides wrap well and tie tight, would be appreciated


All replies are as usual much appreciated.... thank you..............fly



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Guest TOSGcentral

Hmmmm! I would dearly love a scanned copy of that drawing for several reasons:


  • The TST was not built until 1987
  • The (one only) Sprint was built in 1988
  • The harbour bridge wing tip former did not come out until 1988.



To answer your questions:


First up there were two distinct types of Thruster Universal trailer. Neither was intended for the wings to be carried other than ‘racked’. This is for the several reasons of sideage wind, contamination to the wing skins and the trailers lacked the vertical support to take rigged wings. Having said that the racked wings can be carried rolled in their skins with the ailerons still attached. They will fit in the mounts provided.


The webbing is to support the racked wings and the lift struts are piled on top usually.


The trailer can take the full length of the racked wing.


The trailers were designed to take the Thruster without exceeding maximum overall length. However, you will have more than the 4’ permitted rear overhang so must mount a red flag/banner type thing on the rearmost portion.





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Guest TOSGcentral

Fly was kind enough to promptly send me a scan of the drawing.


It is of the later model Thruster Universal trailer so the comments given above are accurate.


The appearance of 'Sprint' and a partially obscured 'T designator' certainly has my interest although they were almost certainly added later to a blank drawing when allocated to an aircraft handbook.


If anyone else has any documentation with Sprint or T100 on it then I would appreciate being told. They are still around. I recently obtained an original factory brochure for the T100 from Steve Meddings. Infuriatingly it had no drawings or photos on it.


Chances are that a brochure was also prepared for the Sprint???







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  • 3 weeks later...
Guest TOSGcentral

Thanks Joan.


Just an identification point on the photo Joan has supplied.


'DF is a TST but has been retrofitted with a T300 pod and has the full height T300 windscreen as well. So it looks a little different from the normal TST although the wings (apart from the retrofit aerofoil section lift struts) are quite standard.





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On top of what Tony has written the wings came with a tough polycloth bag that the wings were slid into for further protection. there were some foam blocks also inserted into the wing to keep the tubing from damaging itself. the only time wings were transported assembled was in the large enclosed trailer that carried two Thrusters. the original trailers were manufactured by Classic Trailers in the Sutherland Shire, Sydney.





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Trailer with assembled wings


Hi Guys,


I scratchbuilt a trailer to carry my Thruster, and it carried the wings fully assembled.


Each wing bolts to an approx 4ft square rectangular frame of 1" RHS, using the standard wing attachment points. Each of these rectangular frames is pivoted where it attaches to the trailer, so the wing can go from horizontal for attachment to aircraft, to just past vertical for stowage on the trailer. The horizontal position has the wings at the same height as the aircraft so in theory one can just wheel up the fuselage and attach a wing,( in practice it is nearly impossible). In the stowed position there are shaped wooden blocks with padding to support the wing ends. I added a small jib which could swing out and support the weight of the wing during assembly, but it never worked properly and I removed it later. The wings are stowed leading edge down, bottom face to the outside.


The fuselage is towed tail first, with the rudder and tailplane attached, and the rudder locked with padded clamps. The towball is 200mm horizontally in front of the back of the rudder, the trailer main frame is two 50mm RHS at 1800mm apart, and the rest of the skeletal frame is 25mm RHS and triangulated everywhere (i.e. a space frame) as a result the entire frame is rigid, so there is no twisting or bending which would cause rubbing of the wings, the Thruster is securely bolted to the frame at the tops of the springs, so everything is one big stiff structure. The propellor boss overhangs the trailing ends of the wings by ~ 200mm


The lights and number plate are mounted on a duckboard, which attaches to the wing ends at the rear, so technically there is no overhang. It was registered in NSW as a "boat trailer" in about 1994, they had no issue except wanting longer mudflaps.


The springs were really long and soft automotive leaf springs. It's nearly 8'wide (2250mm), with a hollow axle. It could be made narrower, but I have the wide wheelbase (2200mm) Thruster anyway. I screwed tarpaulin studs (like they use on utes) to the frame, and fitted a shaped tarpaulin front end. You can't tow it with a tarpaulin over the whole thing as it flaps a lot. I've never had issues with crosswind towing or speed wobbles upto 110km/hr.


I've used it to drag the Thruster upto Mackay from Newcastle on two occasions, so that's 6,400 kilometers total on long trips, plus several local trips.


Only issues were


(a) bent mudguard due kangaroo


(b) cracked welding around mudguard- added braces


© fuel consumption


(d) finding big enough parking spaces


(e) nowhere to put the elevator, propellor, toolboxes and other paraphenalia


Given the extra effort required in handling the assembled wings, and the careful choreography to get the fuselage onto the trailer I don't think there is much benefit compared to racking the wings on the "universal trailer" (I still have to remove ~ 10 battens anyway to accommodate the cockpit width). If you were to make a sufficiently large fully enclosed trailer, then you could carry the wings fully assembled. But the trailer would be the size of a large caravan, this may be a viable option where you are using the trailer instead of a hangar for storage. The wings & fuselage would fit together better (i.e. narrower trailer) if the wings are carried leading edge up, but it would be difficult to support the weight on the flap edge, and the prospect of damaging the flaps through handling is always an issue.


From my experience the only reasons you would use a trailer are


(a) as a cheaper alternative to hangarage


(b) to recover a damaged aircraft.


In my opinion, for long distance travel the best approach is with two aircraft and one large ground vehicle, and do it as a two family holiday.


Cheers, BobT



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Guest TOSGcentral

Good stuff Bob! A wealth of ideas and experience there.



A few additional comments if I may.



I would not minimise the trailering side loads – been there and done that with much glider towing. I have never had a problem with a Thruster, racked, on a Universal as they are normally so heavy-on at the draw bar/coupling.



On the other hand you can get modified trailers that look much like standard Uni’s.



Scott brought his newly acquired TST through here a few weeks ago and this trailer had certainly been tweaked. It was almost in perfect balance when loaded – ie you could lift the draw bar with just a couple of fingers. In my view that is ‘conditionally unstable’ and could result in some spectacular swings as the result of bow waves from passing large vehicles. No ‘war stories’ here about that sort of thing although I have had a few spectaculars myself and some consequent dramas.



Bottom line is make sure that you have at least 20 kg lift weight on the draw bar when putting the trailer onto the prime mover. A bit heavier is OK but watch the crushing force on the car’s rear suspension as you can have your wheels in contact with the wheel arches.



The towing layout of the Thrusters is also of interest as they normally tow tail first.



With anything other than a rear enclosed Thruster then you are towing a ‘tail parachute’ that adds significantly to drag (read fuel consumption) and can add to swing problems if the trailer is marginally balanced.



On top of that the aircraft itself has a reversed airflow so any dust, rain etc goes into the cockpit – and instrumentation. You should therefore seal the cockpit as best you can for towing to avoid this sort of thing and improve rear end airflow.



My major disagreement is with Bob’s last statement in his post – which is fair enough in itself for an experienced Thruster jock. But I know my way around Thrusters and did get caught myself. So one ‘war story’ for you but some common sense first.



Flying any newly purchased aircraft home, particularly over long distance, can be quite an experience if anything is wrong with it. You are going to find that out and your first landing could well be a forced landing somewhere that you have never been! This is particularly exciting if you have no, or little, time on the type – especially a Thruster!



There is only one solution to that and it is long distance trailering. Get the new aircraft home, get to know it, fly it in familiar surroundings that reduce your personal pressure if something does go wrong.



This is my standard advice to anyone who calls on this issue. It may be a bastard to organise a trailer but do it. You can get plenty of free advice from TOSG!



OK – the war story! Like many ancient flying instructors I have the traditional back complaint – a yellow streak a yard wide right down the middle! I am very careful about what I do because I go where many of you may not wish to go. That is not bravado it is merely a case of weighing up the possibilities and ensuring that you have answers before the question is asked.



So I had a ferry flight to do on a sale. I knew the aircraft – it was one of the Super Thrusters (Flaps, fully enclosed, full drag reduction and all the rest of it) and I had already briefly flown it – but seen it fly often. I also trusted the owner.



At the time I was recovering from a particularly unpleasant viral skin infection that was sensitised by heat. I felt that I was more or less OK and knew that I would have to command the ferry flight – but I took an experienced Thruster instructor with me as ‘safety pilot’ as I was still a tad unsure about myself.



There were a few minor dramas on getting going but nothing too taxing. 20 mins of course keeping flying demonstrated that I in fact had a bent aircraft on my hands and the consequent fuel consumption was going through the roof.



That latter point is a challenge in a Thruster because the tank sight gauge does not come readily to view.



The heat in the fully enclosed cockpit became extreme for me and my virus was organising a barn dance to celebrate. We took it in turns to unstrap and strip back to shirt sleeves – our flying jackets being stuffed under the seats.



We then had a radio failure and had to divert to fix it as we had a large MBZ to cross. We also refuelled and did some calculations that turned out a tad grim.



My co-joe, although by now was doing most of the flying, turned out to be not quite as adept on Thrusters as both of us thought he may be and I had to do the landing. The weather was still lovely and clear but damn the wind speed was going up – on the nose – so there were various incantations to the gods and the whiz wheel with the results being a bit gloomy.



45 mins later we were back on the ground buying yet more fuel to ensure that we could make it to Watts in one go. That was a tricky strip being at 90 degrees to the prevailing 25 knot wind and tree lined both sides so you got curl-over and wind shadow gradient. The co-jo lost it again so I landed it again and was starting to feel really evil.



I elected to do the take-off as I had had enough excitement for one day and let him have it once we were over 1500’ agl – it was only a basic map reading exercise and course heading after that!



But no peace for the wicked! I steered us through that bloody horrible little corridor alongside Coolangatta and then relaxed a bit. Meantime we were on the Brisbane main freq and being regaled by some banner towing twit just inside the CTZ having an argument with ATC and they were arguing about a few hundred yards. But it was obviously important to somebody or other. It was also difficult to intrude with our routine airspace clearance calls that at least BN did acknowledge!



Next challenge was my co-jo lost the plot and was heading for some impressive large sheds on the southside of Bne that he was convinced were the ‘railway museum yards’. They had been built out years ago and there were now a lot more such sheds and we were 15 degrees off course and about to join the banner towing guy in being abused by BN ATC. I pointed out that the bend in the Brisbane river had been there for several thousand years, had not moved recently, and we were supposed to bisect it exactly for entry into the Amberly military CTZ.



So I did that bit and the MBZ passage myself and by now I was really ill. I kept control for the landing at Watts because I did not want a problem then and we did arrive with the revised flight plan of 15 ltrs left in the tank.



We put the bloody thing away, I went home and went to bed with a full bottle of port and felt much better the next day! And I arose to what would be three weeks detailed work finding out what was wrong with the aircraft and fixing it!



There are two important flight safety issues here. Do not fly when you are still ill even if you think that you will be OK and have a safety jock with you. Things may not go as planned but as pilot in command you have to COMMAND and be able to cut it. I was too marginal in these circumstances and actually had few reserves left.



Even if you actually know the aircraft (or think you do) be very prudent about taking it on a committed first (and long distance) flight – things (so many things) can go astray. Best to trailer her in and take it in your own time in your own known surroundings.









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Trailering : Best way to get your new plane home




Thanks Tony for pointing out my omission.


One of the most obvious reasons for trailering it is on aircraft acquisition. Having a new pilot fly an unfamiliar (and most likely dodgy) aircraft long distance is a recipe for disaster. You should assume if you buy an aircraft from anyone but Tony, that it almost certainly has one or two minor irregularities, which can be hazardous in all but the most competent pilots hands.


Most aircraft accidents are not caused by a single factor, but a combination of individual factors, each of which is manageable individually. An unfamiliar aircraft in an unfamiliar location already has two factors stacked up, toss in some equipment failures, a bit of illness, failing light, low cloud, fuel, a missing map... suddenly all the holes line up on your pieces of swiss cheese.


The moral here, as is Tony's war story is always to have a backup, other options, a spare, redundancy, an alternative, plan B, an alternate strip, he was lucky enough to have a spare pilot!


I bought my aircraft as a complete aircraft, but with "some assembly required" from the Thruster "Factory", I modified an 8x5 trailer to pick it up.


I hadn't finished my license by this stage.


But the reason I built the trailer was to take the Thruster up to my family in Mackay over Christmas.


I actually passed my license and passenger endorsement about 2 weeks before the first trip to Mackay, I didn't have a X-country endorsement at that stage anyway.


So I based myself just north of Mackay and flew around for a couple of weeks from there just honing my "aviating" skills. You really need to build up a lot of experience before undertaking any kind of epic adventure.


A year later I went up again by trailer, and with considerably more experience under my belt, this time we went as far as Hamilton Island (including a 5 mile overwater leg) This time we were mixing it with 767's into Proserpine, and the really windy Whitsunday strip, and finally flying into the Control Zone on Hamilton, with an interesting landing and takeoff on a 3km bitumen strip in 15 gusting 20kts, with some really interesting orographic wind flows. (On takeoff we were at 2000' before the end of the runway).


So in summary, I had some 6000km of trailer miles, before I went on my epic adventure (7000km Red Nose round trip) and even then I did it in company. (But I think I'm crossing over to the other topic!)


As far as trailer balance goes I think mine is about 5% on the towbar, and a bit more with full jerrycans, RTA recommend around 10%, and I'd agree with that. It's easy enough to push it around with a jockey wheel (But always remember to completely remove the jockey wheel and carry it in the boot!). My previous experience with towing trailers is that having a low c.g. and wide track yields good stability, and that's what I built into the trailer. Soft springs tend to destabilise the trailer. Standard leaf springs with rear shackles add stability, novel suspension types should generally be avoided.


Cheers, bobT



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Thanks Joan.Just an identification point on the photo Joan has supplied.


'DF is a TST but has been retrofitted with a T300 pod and has the full height T300 windscreen as well. So it looks a little different from the normal TST although the wings (apart from the retrofit aerofoil section lift struts) are quite standard.



She's also got original-style curved 2-leaf undercarriage springs. you can't see them but you may notice the pod is sitting slightly lower than you may be used to seeing - about 2 inches in fact, which I believe makes it slightly easier to get into a three-point attitude than with the later straight 3-leaf springs.

I know Tony disagrees 025_blush.gif.9304aaf8465a2b6ab5171f41c5565775.gif





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