South African aviation scene.

[F10]

Things have been quite vibrant in South Africa with recreational flying in the last decade or two. Jabirus being built in George, is that still a thing? Sling aircraft, gaining popularity and respect, Bushbaby, SA version of the Kitfox which seems to have cooled off? Anyone got news or news of any interesting developments?

[Yenn]

It is the home of MGL instrumentation.

[Bruce Tuncks]

I reckon they have a better govt regulation setup there...  maybe our lot have too much money and power.

[Thruster88]

There is this aircraft,  something jabiru could match if they embraced the 915.

 

https://www.slingaircraft.com/aircraft/sling-hw/

[F10]

Yeah, the Slings are pretty cool! I think they are now building them in the USA under licence.

[LJS]

On 11/05/2021 at 4:47 PM, Thruster88 said:

There is this aircraft,  something jabiru could match if they embraced the 915.

 

https://www.slingaircraft.com/aircraft/sling-hw/

I have a strange link to the Sling Aircraft. One of my instructors - Steve Roe - had a hand in the design of the sling back in the early 00's

[RFguy]

How about just copying the molds for the J230D mm for mm  ?

A fibreglass outfit could do that. 

 

The J230 airframe is super...  The glass fuselage is very forgiving. 

 

It is interesting there are some hybrid designs like the Glastar- cro-mo tube frame, glass exterior and surfaces.....

 

 

 

 

 

[pmccarthy]

How about a J230 from carbon fibre? It would have a great load capacity.

[RFguy]

I don't know much about carbon fibre (CF).

Not sure if it  deforms and bounces back under load like fibreglass. Big plus.

I am sure it can if you get the right lay-up. But then any repairs are complex...

 

The fibreglass construction is by all evidence forgiving and reproducable. 

 

There would be some weight advantages to CF. From what I see the glass plane for the same size isn't any lighter than the tube+sheet metal aircraft (like the Brumby I know) , but certainly is easier to get nice organic streamlined, smooth hulls and shapes.   Given what a powerplant weighs, not sure that there is much reason to go much lighter in a J230 size aircraft.  Nice to have a bit of weight  (stored energy). 

 

 

 

Edited June 21, 2021 by RFguy

[marshallarts]

On 22/06/2021 at 6:13 AM, RFguy said:

Nice to have a bit of weight  (stored energy)

I couldn't agree more.  I'm not a pilot these days, but was back in the 1980s and 90s.  And for a glorious few years we owned an old Beech Debonair - now that had a bit of heft to it!  Built like a tank, it shared a lot of components with the Bonanza, and even a few with the Baron I think (e.g. landing gear).  MTOW was about 1350kg if memory serves, and that weight certainly gave it a lot of stability in the air.  I really wouldn't want to fly anything really light, and the thought of a 600kg MTOW makes me shake my head a bit.

[pmccarthy]

But 600 kg is where you are going if AVMED gets you in the crosshairs.

[marshallarts]

3 minutes ago, pmccarthy said:

But 600 kg is where you are going if AVMED gets you in the crosshairs

Well that may be true, and it might happen if it were the only choice.  But the likelihood of my getting back into flying is vanishingly small, so it will probably never be a decision that I have to make.

[Bruce Tuncks]

Carbon is a lot stiffer than glass, and this is good and bad. With glass, the resin fails first and this gives a milky appearance to overstressed areas.  Not so with carbon.

Carbon dust also kills you faster than glass dust. Carbon is biologically more active.

BUT carbon is lighter.And stiffer. Modern big-span sailplanes have to use carbon or the wings would twist and muck up the spanwise loading.

If you wanted to make a super fast Jabiru you could make cantilever carbon wings instead of the strut-braced glass ones. This would give you about 15 knots and cost about 30,000 dollars. It would also make it unrepairable, at least by a mug like me.

Personally, I like glass better and yes I know this shows my age.

[RFguy]

ahh I dont think it would give you 15 kts..... Those wings are pretty good already....
maybe 3 kts without the struts  but I agree with your general thrust (no pun intended).

 

[Bruce Tuncks]

My son, the stuck-up Lancair owner, says struts cost 15 knots, but what would he know.

When I sharpened the trailing-edge of my old struts ( yep, they were real round at the back), I hoped for 3 more knots but alas I can't see it.

Later Jabirus have a different strut extrusion which is already sharp at the back.

I have been told though that there is a law of diminishing returns on aerodynamic improvements so bugger it you can't do ten things at 3 knots to get 30 knots.

[Thruster88]

The nose wheel on a 150-160 knot RV-A only costs 2knots compared to an identical tail wheel model. 

[F10]

Yeah interesting this, I got rid of the wheel spats on my Gazelle, two rear ones were already off and gone walkabout when I bought the aircraft, only nose had it. It to me it’s like the three Musketeers..all or nothing! Looks bit like a Tripacer, one of those aircraft that actually looks better without spats in my view. So, question is, what is better, losing 3 kg weight, or the drag? Weight loss will reduce drag very slightly, but to me, at speeds below 100 kts, drag becomes less of an issue, exponentially. Remember, twice the speed: equals four times the drag, four times the lift and control effectively four times better. All those vary as the square of the IAS, simply put.

[Bruce Tuncks]

I have wondered about skeleton spats for the Jabiru. the wheel is exposed, and the spat consists of a front and rear fairing . This makes pumping up the tyres easier and keeps the spat slimmer. They don't look good though. Anybody tried them?

[Old Koreelah]

On 04/07/2021 at 4:36 PM, Bruce Tuncks said:

I have wondered about skeleton spats for the Jabiru. the wheel is exposed, and the spat consists of a front and rear fairing . This makes pumping up the tyres easier and keeps the spat slimmer. They don't look good though. Anybody tried them?

Westlands did; bloody ugly result:

 

[Old Koreelah]

I never liked the look of wheel pants; to be effective, they need to be large and carefully designed.

I built mine as part of streamlining efforts. Got the glide ratio up from about 1:7 to almost 1:10, which should make a difference if things go quiet.

 

Testing with and without the spats showed a respectable reduction of over 10% in fuel burn and about 4% more speed, so they work.

 

But… if I land on a black soil paddock they might block up with mud and lead to a nose over. One reason all this wet weather has put a dampener on my flying.

 

[RFguy]

can you convert to retractable ? (whole wheel or retractable spats ?)

[facthunter]

If you have mud around your spats should be nowhere to be found. Even pumping the tyres up is a drama.. Nev

[Yenn]

I have cutaway wheel pants on the Corby. Don't know what speed saving is as I put them on from day one.

[Old Koreelah]

10 minutes ago, Yenn said:

I have cutaway wheel pants on the Corby. Don't know what speed saving is as I put them on from day one.

Can we have a pic, Yenn?

[Thruster88]

Pilot Bambi checks out the new Sling high wing. I think they will sell a lot of these. Performance, reliable engine, parachute. It works for Cirrus.