Sling 4 Around the World

[richard C]

These guys are amazing. I was there only a few days ago. Mike and I went flying in the standard Sling and I was blown away by its performance, handling and cabin space.

They told me about their plans for a 4 seater - and now we see it taking shape. They really get stuck in.

The best of luck to you guys.

Keep us in the picture, and let's have lots of photos.

All the very best - you deserve it.

Jim

IMG_4248.JPG

Jim - can I put you on the spot ? You have flown many types - what did you think ? She's a beauty, ne ?

[Kwagga]

Sling 4 around the world would be something...sling 4 around the world with 4 on board .... amazing

[jimdavis]

These guys are amazing. I was there only a few days ago. Mike and I went flying in the standard Sling and I was blown away by its performance, handling and cabin space.

They told me about their plans for a 4 seater - and now we see it taking shape. They really get stuck in.

The best of luck to you guys.

Keep us in the picture, and let's have lots of photos.

All the very best - you deserve it.

Jim

IMG_4248.JPG

Jim - can I put you on the spot ? You have flown many types - what did you think ? She's a beauty, ne ?

Richard, it was a short flight on a miserable gusty day with a mean crosswind so I wasn't able to do everything I would have liked - like settling down at different power settings and looking at airspeed and fuel flow etc. But despite the conditions I thoroughly enjoyed the aeroplane.

I was amazed that it had a big plane feel, it didn't have that skittish feel that many very light aircraft have (particularly with the elevator) and yet the controls are responsive, positive and beautifully harmonized - in fact it is an absolute joy to fly. Also, being based at the coast I was expecting really sluggish Reef performance, but not at all - the Sling fairly jumped off the ground and climbed like hell. Stalls, with and without flaps are simple and straightforward - no wing drop or anything silly, and steep turns are a non-event with only the lightest stick pressure to keep the nose on the horizon. Visibility is fantastic, and being a low wing, you can see whats going on in the circuit while you are turning. Also, being a low wing you don't have to tie it to the planet every time the windsock lifts away from the pole. Finally, the real reason that I love it is that it let me do a greasy landing in that gusty crosswind - a real ego-booster. How could you not fall in love with the Sling. What would I change? I'd like toe brakes - but apparently they are on the way, and I would like manual trim - instead of the electric one, but that's just me.

All together a wonderful aeroplane. If I was still in the flying training business now I would be banging on their door for as many as they can produce.

JIm

[richard C]

Mark G took me for a flip - exactly the same experience. Flew on rails. Steep turn after steep turn with complete ease and confidence. No skittishness whatsoever. Felt big, stable and yet fully and willingly responsive. For a low hour (ppl) like myself, it just felt like the easiest and safest aerie I had ever flown in, and yet still sporty - certainly no plodder.

[Dave Mc Naught]

Incredible to see the Slings taking shape when I visited The Airplane Factory this weekend. Well done guys.. will be following the Sling 4 route. Here's the link to the Aircraft Type discussion forum on Avcom..

viewforum.php?f=176

[pieter001]

I can only imagine that the SLING 4 will be a fantastic aeroplane if the 2 seater version is anything to go by. The Airplane Factory has also proven that once committed, they get the job done and well at that.
I would be very keen so see other engine options! I've got nothing agains the Rotax, but 115hp I'm sure is not going to be moving the airframe through the air at great pace I imagine. The ADEPT 280hp ADEPT may be a little too much, but something like a IO 320/360 could be a fantastic combination.
It is time we get something that can potentially challenge the RV10 as a homebuilt metal 4 seater. This market is hugely popular and OWNED by the RV10 is seems. The SLING 4 with a 200hp could be a fantastic and affordable rival in this segment and it still is proudly SA!

[2000andmore]

To all at the Airplane factory,

An absolutely amazing achievement.....to build a new aerie in this short space of time. Fantastic effort guys. May I wish you a safe flight to Oshkosh, where I will meet you on arrival! When I saw the prototype a few weeks ago, I thought that there was no chance of you completing it in time for Oshkosh.

I love flying the Sling. I am instructing on one at Johannesburg Microlight Academy. It is a great aeroplane and an excellent trainer too.

Good luck,

Gavin Lundie

[NickG]

A simply amazing Project time-line. Saw the Sling up close at the Wonderboom show a couple of weeks back - it is very roomy ...and very purdy too!

Probably sensible to avoid the nearly 4,000 km West Coast to Hawaii leg.

Are there plans during this trip to fly any of the legs high in the flight levels on oxygen to boost ground speed by taking advantage of the retained power at altitude of the turbo charged Rotax 914?

[WillemGouws]

Mike, James, Jean and team

Well done on another mind blowing project! Good luck with the completion and the flight. We look forward to visit the factory and to see the completed aerie.

Your comments on the engine choices will be interesting. Obviously starting with the Rotax 115HP but perhaps a Lyco 320 could result in this aerie being a 130 - 140knot family touring machine? I believe the 160HP Lyco is about the same price as the Rotax 115HP. It will be important to be able to run on Mogas, and I believe that the 160Lyco caters for that.

Anyway, well done and good luck.

Please keep us posted on departure dates etc

Willem

[jpitman]

Today represents exactly two weeks until departure of the Sling 4 to Oshkosh. Here's last night's update on the Airplane Factory website -

The behind the spar and both leading edge fuel tanks in each wing of the Sling 4 have been pressure tested and there are no leaks. They will therefore be finally assembled into the wings over the next few days.

Meanwhile, the greatest single challenge facing the team is the development of the canopy in the tight time constraints facing the project. Far more complex than the standard 2 seater sliding canopy, the 4 seater canopy comprises 5 sections with mid-located gullwing doors which are visible, opened, in the undercarriage-less photograph some entries up. This design will give additional rigidity to the entire airframe structure. The canopy frame, however, which is to be constructed from carbon fibre and glass fibre with epoxy resin, is a complex structure will take some time to prepare. Luckily for The Airplane Factory Manfred Springer, who lives on the airfield, has a 6 by 3 m 3D routing machine and has prepared a blank of the canopy from which a female can be cast. Jean is working on the problem day and night and will be doing everything necessary to ensure that by the end of this coming week a fully functional (and knowing Jean, probably also beautiful), canopy arrangement is available).

Simultaneously Terry is on the final straight with the small brackets and other finishing elements of the centre fuselage on Solid Works. Most of the remaining centre fuselage parts will be punched out tomorrow (Saturday) and construction on the centre fuselage will commence in earnest on Sunday/Monday. Although the control arrangements are slightly different in the Sling 4 and the additional seats and changed wing placements require some changes, conceptually the Sling 4 centre fuselage arrangements are materially the same as on the standard Sling. Three months ago 10 people, 5 of whom had absolutely no mechanical experience, built a Sling in 7 days. (For a teaser on that see http://www.youtube.com/watch?v=yShaGeKPGyo). Now, with an entire factory full of experienced aircraft assemblers, the Sling 4 (sans canopy anyhow) should be a cinch to complete in 6 days. Of course unlike with the 7 days aircraft, the rear fuselage and wings are already almost complete!

More news will follow after the weekend. For those doubters, however, The Airplane Factory’s confidence that the aircraft will be completed by next weekend is demonstrated by the fact that the Director for Civil Aviation in South Africa, Mr Thwala, has agreed to launch the prototype at 10h00 on Monday morning, 11 July, 9 days hence. We are honoured to host Mr Thwala and we also invite those who are interested in seeing ZU-TAF completed to attend the gathering. We promise a full tour of the factory to those who are interested.

Until next week, sala kahle.

Computer rendering - Sling 4 canopy frame.jpg

Sling 4 canopy blank - routed by Manfred.jpg

Terry and Ruan hard at work.jpg

[jpitman]

To answer two of the questions that have been posted -

Nick G - do we intend to fly any of the legs on our planned trip at high altitudes using oxygen so as to get maximum benefit from the turbocharged engine?
We don't - mostly because we don't really need to and it adds a bunch of complications. Since we decided to change direction early during the week we're also flying into the wind most of the way - so altitude may not help us much - in fact we may want to be flying lower. Also, very heavily overloaded at higher altitudes the wing needs to fly at higher angles of attack and I'm not sure we'd actually obtain such a benefit. Finally, and especially on the first half of the trip, with only two crew on board, the endurance can quite comfortably be increased to in the vicinity of 30 to 36 hours with a couple of jerry cans on the back seats. That's quite substantially more than is required anyhow.

Willem Gouws and Pieter001 - on the question of Lycoming and more powerful engines in general for the Sling 4

Different engine options are something we speak about quite often at The Airplane Factory. There are currently two Sling builders who are planning Jabiru 120hp engines for their aircraft. We're assisting them with the installation and will are interested in testing performance once flying. One obvious problem with a Lycoming 320 engine is that it weighs at least 45 kg more than a Rotax 914, a very substantial extra weight to put right up at the front of the plane. A Rotax 914, being turbocharged, also gives 115hp right up to about 15 000 feet. At a 3% loss of hp per 1 000 feet, up here at 5 500 feet in JHB, with the density altitude about 8 000 on most days, a 150hp Lycoming motor is in any event only giving about 114hp. A Jabiru 120hp is giving less than 100hp. Finally, the Sling 4 is a light 4 seater with a reasonably high drag wing, fairly low(ish) wing loading, lots of lift and accordingly not so much speed. A large engine making it faster means more gas burnt without that much benefit. Instead we have plans to develop, as our next aircraft, a 180 knot 5 seater high wing aircraft which will use, at least for starters, a substantial Lycoming or Continental engine. Don't' hold your breath though, it's gonna take a while!

For some teasers on what a movie about the 2009 flight around the world might look like, see http://www.youtube.com/watch?v=kA7DGqoPdgg

[pieter001]

Thanks for the update, it is well received.

Now the effort is against time, so I wish you the very, very best in all and everyone in the team's effort. Will chat to Michiel and see if I can hitch a lift with him to the lunch maybe....

Look forward to the next update.

[frikie]

Gents I looked at your clip, is there more?
Loved it.

[Steve]

Computer rendering - Sling 4 canopy frame.jpg

Get Jean to take a look at the Glasair III canopy...

[WillemGouws]

Thanks for the feedback James and good luck with the next 7 days!