What can be done???

[Downunder]

Goodyear Inflatobird. One of the many efforts to make a glovebox pilot retrieval aircraft for the USAF...

Nah.....this is the one I was thinking of......actually a trike....great for a bit of fun in a paddock or on the beach.

Comments seem to suggest $12000 is a bit rich.......

 

 

 

[Phil Perry]

Not true in the UK Scott - schools have to use factory built aircraft AFAIKCheers

 

John

Not strictly true John. . . . .

You are allowed to learn to fly in your own kit built aircraft, providing that it doesn't have multiple owners, ie, as with a syndicate, unless the syndicate owners are of the same blood family ( . . .. then it's OK. . . .[?] )

 

. A solo owned kit aircraft is legal for full ab-initio and further training in the UK at the present time, but things are quite fluid, and with the European Union throwing all sorts of regs at us at the moment that could well change. . . .

 

Phil

 

 

[Bob Llewellyn]

Nah.....this is the one I was thinking of......actually a trike....great for a bit of fun in a paddock or on the beach.Comments seem to suggest $12000 is a bit rich.......

 

Oh well, the French are just... french. Having got that bit of racism out of my system, the stresses in such a fabric balloon are actually quite high, and the technology of garaunteeing the stitching strength etc is pretty high. Look like fun though.

The InflatoBird packed into an 18" diameter tube, about 6 feet long, plus the power plant (a 72hp McCoullacghragh); and inflated into a 2-seat, side by side motorglider. The same USAF requirement spec gave us the 2nd application of the Rogallo wing, the Bensen gyrocopter, and I think started the WASP jet platform program...

 

 

[Guest Crezzi]

Not strictly true John. . . . .You are allowed to learn to fly in your own kit built aircraft, providing that it doesn't have multiple owners, ie, as with a syndicate, unless the syndicate owners are of the same blood family ( . . .. then it's OK. . . .[?] )

 

. A solo owned kit aircraft is legal for full ab-initio and further training in the UK at the present time, but things are quite fluid, and with the European Union throwing all sorts of regs at us at the moment that could well change. . . .

 

Phil

Thanks Phil - I interpreted the earlier post to assert that it was unconditionally possible to use kit built aircraft for training. The UK rules are, in practice, similar to the Aussi ones - flying schools can only use factory-built aircraft. ?

 

Cheers

 

John

 

 

[M61A1]

Oh well, the French are just... french. Having got that bit of racism out of my system, the stresses in such a fabric balloon are actually quite high, and the technology of garaunteeing the stitching strength etc is pretty high. Look like fun though.The InflatoBird packed into an 18" diameter tube, about 6 feet long, plus the power plant (a 72hp McCoullacghragh); and inflated into a 2-seat, side by side motorglider. The same USAF requirement spec gave us the 2nd application of the Rogallo wing, the Bensen gyrocopter, and I think started the WASP jet platform program...

I read an article written by some US Navy pilots on some flight testing done in the Goodyear Inflatoplane, it was very interesting, I believe it was scrapped because of structural issues, despite having wire bracing to keep the wings where they should be, they still occasionally folded.

 

 

[Bob Llewellyn]

I read an article written by some US Navy pilots on some flight testing done in the Goodyear Inflatoplane, it was very interesting, I believe it was scrapped because of structural issues, despite having wire bracing to keep the wings where they should be, they still occasionally folded.

...but it bounced off the ground and kept going!!... didn't it?

 

 

[M61A1]

...but it bounced off the ground and kept going!!... didn't it?

Ummmmmmmmm....nope

 

 

[Bob Llewellyn]

Ummmmmmmmm....nope

....oh. Maybe that's why there are not more of them around...

 

 

[turboplanner]

So I take it we can rule out that alternative for revitalising grass roots flying then.

 

 

[Bob Llewellyn]

So I take it we can rule out that alternative for revitalising grass roots flying then.

Actually, with FEM for design, it should be much easier to come up with an inflatable structure that'll stay up (the french trike appears a logical evolution of their high-performance parawing technology, not an exercise in FEM). Costwise... how much do two parawing canopies cost?

 

 

[Dafydd Llewellyn]

Look, the way to get cheap entry-level aircraft is NOT to build crap using commercial alloy tube & pop rivets, or any such approach. The only way that works, is to build quality products that are sufficiently durable that they are still viable when they get to their third owner. Forgotten your first car? I bet it was decidedly second hand - mine certainly was. I soon learned which makes & models were heaps, and which ones kept going. It's exactly the same with aircraft, only a greater percentage of them in recreational aviation were not built to last.

 

The reason for this is that the idiots who wrote the design standards did not make durability a prime requirement; if they had done so, we'd have a considerable accumulated pool of sound, entry-level aircraft by now. We've lost two decades through this bloody stupidity. That's water under the bridge - but FFS do NOT continue to make the same idiotic mistake. Stop looking for the mystical $10K off-the-shelf flying machine, and start refusing to purchase crap. Think of your resale value, instead. An early Jabiru with one of Ian Bent's engines in it would be about the best you could do in utility per dollar, with what's around currently. OK, if you're a Drifter fan, LOL - but it's not everybody's ideal flying machine.

 

Start pushing for a small weight increase with the added weight used to make it more durable, instead of using it to add bells & whistles. If people do this NOW, we'll have a decent pool of good third-hand aeroplanes in a decade. If you go the other way, all there will be in another decade is a lot of useless scrap tube & sailcloth, and people still looking for a cheap entry-level aircraft.

 

If you want recreational flying to grow, this is the ONLY way.

 

 

[Bob Llewellyn]

Look, the way to get cheap entry-level aircraft is NOT to build crap using commercial alloy tube & pop rivets, or any such approach. The only way that works, is to build quality products that are sufficiently durable that they are still viable when they get to their third owner. Forgotten your first car? I bet it was decidedly second hand - mine certainly was. I soon learned which makes & models were heaps, and which ones kept going. It's exactly the same with aircraft, only a greater percentage of them in recreational aviation were not built to last.The reason for this is that the idiots who wrote the design standards did not make durability a prime requirement; if they had done so, we'd have a considerable accumulated pool of sound, entry-level aircraft by now. We've lost two decades through this bloody stupidity. That's water under the bridge - but FFS do NOT continue to make the same idiotic mistake. Stop looking for the mystical $10K off-the-shelf flying machine, and start refusing to purchase crap. Think of your resale value, instead. An early Jabiru with one of Ian Bent's engines in it would be about the best you could do in utility per dollar, with what's around currently. OK, if you're a Drifter fan, LOL - but it's not everybody's ideal flying machine.

 

Start pushing for a small weight increase with the added weight used to make it more durable, instead of using it to add bells & whistles. If people do this NOW, we'll have a decent pool of good third-hand aeroplanes in a decade. If you go the other way, all there will be in another decade is a lot of useless scrap tube & sailcloth, and people still looking for a cheap entry-level aircraft.

 

If you want recreational flying to grow, this is the ONLY way.

Just look at all those Skycraft Scouts still on the flightlines!

 

 

[turboplanner]

Dafydd, you are talking about the next class up. I would agree that FRP sandwich gives a good strength to weight ratio, but there is a cost penalty, and space frame/rivetted aluminium or space frame/fabric can be made to perform at a much lower price. There are many Buyers in that class being priced out not by the airframe but the necessary replacement engines. 80 hp costs too much.

 

The grass roots class needs a max 50/60 hp where the owner can replace pistons, barrels etc at a fraction of the cost.

 

 

[Dafydd Llewellyn]

Dafydd, you are talking about the next class up. I would agree that FRP sandwich gives a good strength to weight ratio, but there is a cost penalty, and space frame/rivetted aluminium or space frame/fabric can be made to perform at a much lower price. There are many Buyers in that class being priced out not by the airframe but the necessary replacement engines. 80 hp costs too much.The grass roots class needs a max 50/60 hp where the owner can replace pistons, barrels etc at a fraction of the cost.

Sure - but the number of them in usable condition for a new-entry buyer is pretty limited - and Skyfoxes have a 4000 hour life, don't forget. As I said, the legacy of the early design standards has prevented the accumulation of a sufficiently large pool of suitable aircraft. That's history now. The reason Skyfox went out of business was that the damn thing was too costly to build, to compete with the early Jabiru. The early Jabs used 65 HP engines, remember? They've been upgraded because that was what was available. You could put one of the certificated 65 HP twins in an early Jab, I suppose, but nobody'd use it for training. It would be a dog on a hot day or away from sea-level. I really don't think that sort of aeroplane is desirable for a new entry purchaser; he's likely to leave it in the trees at the end of the strip. A bit of performance is cheap insurance. From my experience of them, the Jab airframe beats anything else hands-down for its manufacture cost. They'd be ideal for vacuum infusion, instead of the wet layup Jabiru used to use for them.

 

 

[terryc]

Sure - but the number of them in usable condition for a new-entry buyer is pretty limited - and Skyfoxes have a 4000 hour life, don't forget. As I said, the legacy of the early design standards has prevented the accumulation of a sufficiently large pool of suitable aircraft. That's history now. The reason Skyfox went out of business was that the damn thing was too costly to build, to compete with the early Jabiru. The early Jabs used 65 HP engines, remember? They've been upgraded because that was what was available. You could put one of the certificated 65 HP twins in an early Jab, I suppose, but nobody'd use it for training. It would be a dog on a hot day or away from sea-level. I really don't think that sort of aeroplane is desirable for a new entry purchaser; he's likely to leave it in the trees at the end of the strip. A bit of performance is cheap insurance. From my experience of them, the Jab airframe beats anything else hands-down for its manufacture cost. They'd be ideal for vacuum infusion, instead of the wet layup Jabiru used to use for them.

Hi Dafydd, from where I sit I see an over supply of aircraft in the raa mag and other places not selling too well and when they do it appears for less than the asking price.

 

 

[Dafydd Llewellyn]

Hi Dafydd, from where I sit I see an over supply of aircraft in the raa mag and other places not selling too well and when they do it appears for less than the asking price.

Sure you do. Ask yourself why they are not selling.

 

 

[Downunder]

In response to the first post, I don't think it is only the type of aircraft which has driven prices up.

 

Fuel, insurance, cost of living, leases, etc probably contribute more to the overall cost.

 

Simply having a cheaper aircraft may notsignificantly reduce costs and you need to have an aircraft which appeals to students.

 

We have grown into a massively risk adverse nation and to the outsider a "real" aircraft looks safer so it "must " be safer.

 

Perhaps the rag and tubes have gone the way of the horse and cart and will survive with the efforts of a few dedicated individuals and enthusiasts.

 

This is life..........

 

On another note, I think the marketing of the RA inustry has been poor. I took a workmate to my hangar for a fly and luckily there were trikes, gyros, water bombers and various aircraft about. He spoke about it being an "amazing underground subculture" largely unknown by the general population.

 

 

[Dafydd Llewellyn]

There's a place for welded steel tube - in engine mounts, the cabin structure, the odd space frame where one needs the bits inside to be readily accessible. It's too costly to use extensively. I'm quite fond of it, where it's appropriate; I had an aircraft welding licence for a decade, before it got too expensive to keep renewing. There's a place for rivetted aluminium, too; it's lighter than composite for a given stiffness. This makes it good for control surfaces, especially when they are mass-balanced. Given good tooling, it can be quite quick to build; I built a rear fuselage in it - it took a week, much of which was learning time, and weighed 35 lbs., and the structure was not skimped - there's a reason it has been around for so long. Use for single-curvature parts. It's also lightning-resistant - tho that's not a concern for ultralights. Not hail-resistant in thin gauges. There's a place for composites; with clever design, it's possible to come up with an indefinite-life wing, for instance - and they cain't be beat for double-curvature or complex shape parts. However, most of the composite designs one sees are decidedly ordinary; you can't tell from the glossy exterior. English wheels are for craftsmen - not for production. I've just re-covered a set of Blanik control surfaces, in Poly-Fiber. Very satisfying, and good for the karma - but far too labour-intensive for production. The best airframe will use a mixture of construction, each where it suits best. There's no single magic answer; be very suspicious of anybody who claims they've found one.

 

 

[Oscar]

Having just done some extensive repair and upgrade work on a 'totalled' early Jab. can I offer a few observations?

 

What may be considered as 'low-tech' composite structure has some considerable advantages in terms of a general, robust knock-around airframe. Certainly it does not produce the best performance/weight figures such as the high-tech c/f machines offer - but you can examine damage by knock-test and shining a light through the laminate. By comparison, a highly-stressed c/f component that is suspect following a potential damage situation requires laboratory-level equipment to be thoroughly inspected, so the most likely safety procedure is going to be complete replacement.

 

A Jab can be repaired - even some relatively major repairs - pretty much 'in the field', provided attention is paid to things like laminate orientation and reasonable environmental conditions for the lay-up of repair patches (temp and humidity conditions). You don't need an autoclave, even vac. bagging equipment (though the latter can make a difference to the appearance and confidence in the quality of the repair). By following good composite repair practice, you'll get a result that us structurally indistinguishable from the original - and that can be tested by applying test loadings.

 

Jab basic airframes are pretty much unaffected by environmental conditions; you don't have to have concerns about whether it is kept beside the coast in prevailing salty sea-breezes or in high-humidity areas, which can kill wood structures rather quickly - Skyfox Gazelles have vulnerabilities in those conditions. Steel-tube structures can be badly affected by the conditions present when they were assembled - Lightwings are known for varying life of some tubes vs others, that is unpredictable (but certainly repairable).

 

Stressed-skin aluminium aircraft can be seriously affected by a slip-up in prep. or failure to isolate dissimilar metal components. In 1993 I was at the NASM restoration facility at Silver Hill, Washington DC. and saw the work being put into Enola Gay to recover from previous restoration work that had allowed fine sand-basting particles to lodge between the skin and the longerons on the tail-cone - which had almost torn her apart along the 'seams' as moisture trapped by the sand particles and the difference in the alloys between the skin and the longerons combined to produce persistent electrolysis. Electrolysis and fatigue are the killers for stressed-skin aluminium aircraft.

 

Fabric-coverings have UV deterioration life issues; they don't last indefinitely. With modern Stits fabric and good paint, that can be a pretty damn long time - and fabric-covered aircraft (such as the Wittman Tailwind) can be damn hot performers. So far, we don't have anything definitive for Jab. airframes in regard to UV deterioration, but no doubt it will emerge eventually.

 

The point I am trying to make here is: Jab airframes trade-off ultimate performance/lb. for a basic toughness. If you are in the market for a relatively low-cost aircraft to buy and operate, an older Jab is far less likely to have hidden costly problems than almost anything else for the money you'll pay.

 

 

[Bob Llewellyn]

Having just done some extensive repair and upgrade work on a 'totalled' early Jab. can I offer a few observations?What may be considered as 'low-tech' composite structure has some considerable advantages in terms of a general, robust knock-around airframe. Certainly it does not produce the best performance/weight figures such as the high-tech c/f machines offer - but you can examine damage by knock-test and shining a light through the laminate. By comparison, a highly-stressed c/f component that is suspect following a potential damage situation requires laboratory-level equipment to be thoroughly inspected, so the most likely safety procedure is going to be complete replacement.

 

A Jab can be repaired - even some relatively major repairs - pretty much 'in the field', provided attention is paid to things like laminate orientation and reasonable environmental conditions for the lay-up of repair patches (temp and humidity conditions). You don't need an autoclave, even vac. bagging equipment (though the latter can make a difference to the appearance and confidence in the quality of the repair). By following good composite repair practice, you'll get a result that us structurally indistinguishable from the original - and that can be tested by applying test loadings.

 

Jab basic airframes are pretty much unaffected by environmental conditions; you don't have to have concerns about whether it is kept beside the coast in prevailing salty sea-breezes or in high-humidity areas, which can kill wood structures rather quickly - Skyfox Gazelles have vulnerabilities in those conditions. Steel-tube structures can be badly affected by the conditions present when they were assembled - Lightwings are known for varying life of some tubes vs others, that is unpredictable (but certainly repairable).

 

Stressed-skin aluminium aircraft can be seriously affected by a slip-up in prep. or failure to isolate dissimilar metal components. In 1993 I was at the NASM restoration facility at Silver Hill, Washington DC. and saw the work being put into Enola Gay to recover from previous restoration work that had allowed fine sand-basting particles to lodge between the skin and the longerons on the tail-cone - which had almost torn her apart along the 'seams' as moisture trapped by the sand particles and the difference in the alloys between the skin and the longerons combined to produce persistent electrolysis. Electrolysis and fatigue are the killers for stressed-skin aluminium aircraft.

 

Fabric-coverings have UV deterioration life issues; they don't last indefinitely. With modern Stits fabric and good paint, that can be a pretty damn long time - and fabric-covered aircraft (such as the Wittman Tailwind) can be damn hot performers. So far, we don't have anything definitive for Jab. airframes in regard to UV deterioration, but no doubt it will emerge eventually.

 

The point I am trying to make here is: Jab airframes trade-off ultimate performance/lb. for a basic toughness. If you are in the market for a relatively low-cost aircraft to buy and operate, an older Jab is far less likely to have hidden costly problems than almost anything else for the money you'll pay.

Yeah, well, if you want that kind of speed, or economy, or comfort, go and buy a Jab then. For reliable longevity, the Thruster TST family has a few members at over 10,000 hrs TT; and a good pre-flight is equivalent to an airframe major inspection on a jabiru... unlike the Drifter, they don't have multiple-sleeved spars, which is about the only thing att all difficult to inspect on a Drifter (provided you're limber enough to have frequent suspicious squizzes at the underside of the fuselage boom adjacent to the rear bulkhead of the floor raft, or bathtub, or whatever you may call it). Both the Drifter and Thruster two-seaters provide an indefinite life, with good safety, by thorough pre-flights (and timed maintenance on the donk...)

 

 

[dlegg]

I dunno, just my view, but I think it is just a generational thing with young adults now growing up with computers, gaming etc. Older ultralight type aircraft, which there are really a lot of around and quite cheap to buy, simply don't rate with this generation. Not fast enough, too much trouble to learn in, ancient technology(apparently). Hell, these kids don't even want a push bike any more.

 

I tried to get my son interested, he enjoyed the actual flying, but bailed out when he perceived the work load of studying the BAK and nav, met etc as "uncool and over the top Dad" Can't I just fly the thing? Maintenance, preflight, commonsense, WTF? And travel to the airstrip.....I enjoy the country drive......it's just a chore for these young adults, looking at there smart phones all the way. The magic of flight just doesn't have the same impact as in my generation. They just don't seem able to smell the roses anymore............

 

 

[fly_tornado]

There are just a lot of more exciting activities that require less commitment than aviation. Road bikes. Dirt bikes. Jet skis. Cars. etc. they are all eating away at the aviation industry.

 

 

[nong]

The parts count and number of joints in Drifters and Thrusters make them uneconomic.

 

As already pointed out, they cost a lot to build. As the various joints "work" in service these airframes become "loose". This can only be remedied with man/hours.

 

I love two-strokes but really, who wants to burn eighteen litres per hour to travel fifty miles?

 

Lets acknowledge that Rod Stiff has already provided the champion of economy aircraft. The J120 is surely a monster bargain in the "bang for the buck" stakes.

 

This thread has come up with no concept close to what Jabiru has achieved.

 

Jabiru airframes are an example of the previously mentioned "design for less maintenance"concept.

 

 

[Dafydd Llewellyn]

I think you need to refine the definition of "longevity". Some airframes achieve longevity by the "George Washington's Axe" method - I would put the Drifter in this category as well as things like Austers, and most fabric-covered aircraft. Others achieve it by using materials that are corrosion-resistant and readily repairable; the Jabs tend to fall into this class - if you understand and have the capability for, the correct repair techniques. Others achieve it despite using corrosion-prone materials, by careful protection processes; most stressed-skin metal airframes are of this type, but with varying degrees of success.

 

However there are other factors to consider: How easy is it to inspect? This can be a major issue for many forms of composity construction; the transmitted-light method has its limitations. For metal structures, what is the life of the protection system? The economic life of the airframe is pretty much dictated by how good its original corrosion-protection system was - unless the manufacturer used 6061 alloy, which is vastly more corrosion-resistant than the higher-strength ALCLAD materials.

 

Does it have a finite fatigue life? Most structures do in reality, though it has not always been calculated and declared in the maintenance instructions. Be cautious where nothing is stated about the fatigue life of the structure; there's a generation of airframes out there for which the design standard did not require calculation of fatifue life.

 

A "GWA" class aircraft can be restored to as-new condition by extensive replacements - provided you can get them. The multiple-sleeving of the Drifter spars does present a difficult inspection problem, however. The process is always labour-intensive. What really matters is how frequently it is necessary; the Jab was outstanding amongst early ultralights in this regard - apart from the undercarriage legs.

 

A stressed-skin metal aircraft can be extensively restored by de-rivetting and replacing corroded panels - but that's a job that requires extensive experience of aircraft sheet-metal techniques, and may need extensive jigging if it gets past the superficial stage. It can easily cost more than the original purchase price of the aircraft. It gets very expensive if machined, heat-treated parts are involved, and impossible if a major forging is involved, unless you can find a replacement part. A corroded stressed-skin metal airframe is something to avoid, unless you're a fanatic restorer.

 

It is dangerous to generalise on composite airframes; some are practically unrepairable; others can be extensively repaired. Again, unless it's fairly superficial, it's a specialist exercise. The Jabirus have generally proven to be amongst the best in this regard - but there are parts of them that may not be repaired.

 

This subject needs a library of data to understand fully; the best single starting point is FAA Advisory Circular 43.13-1. However it's a minefield for a first-time aircraft purchaser. A prudent would-be purchaser should look up the Airworthiness Directives that exist for the aircraft types he's interested in; they can tell you quite a lot about which types to avoid. Also study the maintenance manual and the spare parts catalog, when you get to the short-list stage. The better these documents are, the easier will maintenance be, generally speaking. After that, go talk to somebody who specialises in maintaining that type of airfraft.

 

 

[Oscar]

Yeah, well, if you want that kind of speed, or economy, or comfort, go and buy a Jab then. For reliable longevity, the Thruster TST family has a few members at over 10,000 hrs TT; and a good pre-flight is equivalent to an airframe major inspection on a jabiru... unlike the Drifter, they don't have multiple-sleeved spars, which is about the only thing att all difficult to inspect on a Drifter (provided you're limber enough to have frequent suspicious squizzes at the underside of the fuselage boom adjacent to the rear bulkhead of the floor raft, or bathtub, or whatever you may call it). Both the Drifter and Thruster two-seaters provide an indefinite life, with good safety, by thorough pre-flights (and timed maintenance on the donk...)

Isn't a spar what you have when you taxi a Thruster through a puddle?