Va and fantastic plastic

[skippydiesel]

I wonder where "STOL" starts and ends today.

If you look up what stol means in the early days it was anything less than 1500ft. A j3 or 3 with a Franklin or the real power house, the Conti 65 armstrong start were all classed as stol. But they really relied on the curvature of the earth to get airborne.

I would say that ANY of our RAAus planes will qualify. My SP 500 at MAUW gets of and over 50' at 400m. If I am solo and half fuel take off is 300m @ 50' and I can put it down in slightly less, tho that scares the Sturt Highway traffic a bit.

Strangely we seem to need to take off and land 2 to 3 times in that distance nowadays.

My advice is to look at the book specs, add a little bit and you will still be under the old stol.

BTW, a lot of pilots don't help themselves coz they build a heavy plane looking for that perfect paint finish then put every instrument they can think of that is worthy of IFR, then have backup instruments as well.

Keep it light, keep it simple, look outside- not at your wizbang panel and enjoy the ride.

Ken

 

Hi Kenisa - Turboplanner is probably technically correct, however I have always just thought of it as the potential of an aircraft to make Short Take-offs and Landings as compared with other aircraft in a similar weight/performance range.

 

Unlike Turbo I do not think the pilots ability has anything to do with this description. True to be able to use STOL you need to be trained/experienced but we are talking about the aircraft's potential ,not the pilots ability to realise it.

[Blueadventures]

Thank you for the invitation/opportunity Blueadventure.

 

First, as most/all of you know, I am in partnership with another enthusiastic pilot, with the aim of promoting and selling the ATEC aircraft range in Australia.

 

Having got that out of the way on to the list you have asked for:

 

My short list of aircraft that ALL fall within the RAA type and have a 600 kg Max take of weight.

 

Pipisteal Virus SW 121

erformance specifications can be found a://www.pipistrel-aircraft.com/aircraft/cruising/virus-sw-121/

The performance of this aircraft has been repeated verified by third party competition ( CAFE Foundation's Green Flight Challenge etc)

 

ATEC 321 Fayeta, 321 Faeta NG & 212 Solo (The 122 Zephyr is a bit slower at 124 knots cruise)

Performance specifications can be found at ATEC Aircraft - Czech manufacturer of light sports aircraft | ATEC Aircraft

Unfortunately I do not have independent verification of these aircraft performance BUT am willing to arrange a TIF so that you can verify, first hand, my claims

 

• The above aircraft all stall at around the 30 knot mark and can cruise in excess of 130 knots at 18L/h or less. All use Rotax 912 engines. With the exception of the ATEC 212 Solo there are flying aircraft in Au
  

 

I am sure there are other aircraft (that have very low stall, combined with high cruise) but non come to mind at this time.

 

Rerefence: "Please re read my comment as I specifically spoke of the Jabiru performance in general. Therfore your comment is not warranted."

 

The start of this conversation: "I see there is a lot of fantastic-plastic aircraft coming out of Europe. you can have it all it seems, speed, low weight, full MTOW, low drag etc" - seems to be a fairly broad question. You dont have to read or agree with my statements but to say they are "not warranted" is a bit harsh.

I find it interesting that in the replies you state you promote / sell Atec aircraft and say stall speed is around 30 kts for the 121. In earlier post you say 32 kts. Spec says 35 kts. I view this type of talk as misleading by sales reps to get a sale and now see why you numbers are so good and better than the book figures. My replies in threads are to tell the story as accurately as possible to others in the real world findings.

[skippydiesel]

I find it interesting that in the replies you state you promote / sell Atec aircraft and say stall speed is around 30 kts for the 121. In earlier post you say 32 kts. Spec says 35 kts. I view this type of talk as misleading by sales reps to get a sale and now see why you numbers are so good and better than the book figures. My replies in threads are to tell the story as accurately as possible to others in the real world findings.

 

 

So I abbreviated a very little - my apologies.

 

The Faeta stalls at 28 knots, the Faeta NG at 30 knots, the Zephyr at 32 knots - all single pilot. Naturally you must increase speed with load (additional person) so add about 3-5 knots. You should also consider variation of air density altitude, wing cleanliness, As with all aircraft, these figures, while achievable in most situations, will vary slightly between individual aircraft and must be considered indicative and best kept above, particularly when close to terrain.

 

I stand by the above and am happy to arrange a TIF for those who are genuinely interested in discovering the truth/fact.

 

The hard reality is there are a small number of (RAA type) aircraft with a genuinely wide operating envelope. The rest ,while excellent aircraft in their own right, can not even come close.

 

Most of the ones with a sub 35 knot stall, struggle to reach 100 knots in cruise at 18L/h or worse.

 

For the most part, those that can achieve a 120 knot plus cruise (18 l/h) have stall speeds above 40 knots - some are struggling to remain within RAA stall requirements.

 

(Rotax 912 ULS fuel consumption is being used as indicative of energy/power needed to reach the air speed quoted. All air speeds are indicated)

 

My factual point is - for about 20 years now, there have been available RAA aircraft that seem to defy the old "truisms" about aircraft being fairly limited in their flight envelop. In the past (and certainly what I received in training) the pilot must decide does he/she want low/slow/STOL or high cruise and high stall long TO/Landing characteristics. Supposedly you cant have both.

 

There is no secret to this capability - As Nev has pointed out, clever wing design coupled with efficient flap design ,allows for wider flight envelope .

 

That the above facts, still seems to cause consternation and denial with the old guard, is to me absolutely gob-smacking but there you go, we are all entitled to our opinions.

[skippydiesel]

Which planes are you speaking of Skippy?

High speed is not always the fastest way between two points. If you have to land to refuel your high speed plane, while the slower one keeps on, then the slow one could be faster. For short runs, say less than 100 milse speed makes little difference.

70 miles at 140 kts takes 30 min plus manouvering on ground, but at 100 kts it takes 42 mins plus the manouvering. Say 38 mins ompared to 46. Not so much really.

 

Hi Yenn - True speed is not everything however, in my mind, speed as related to fuel consumption/power setting is indicative of air-frame efficiency.

 

You dont have to use the aircraft's max power/fuel consumption speed (pilot choice) but when making comparisons between aircraft the strait/level speed at which an aircraft can fly, at a given fuel consumption, allows for the potential purchaser/user to make value judgements.

 

My my little Zephyr, prop setting- advantage TO, is good for about 120 knots at 500 ft ASL, 18l/h (if I hold my breath & squint) - I rarely fly above 110 knots and usually cruise at 100-105 knots, for a fuel burn between about 12.5 -14L/h (the later with passenger). I flight plan at a conservative 14L/h.

[facthunter]

A lot of basic designs just don't try to "clean up" the plane that much, so you hit the wall at about 85knots Fabric and struts (or worse) wires get draggy fast. Composites free up the way for cleaner designs, there's no doubt about that . You can "power" your way to higher cruise speed but it's increasingly wasteful of fuel as you are getting into a L/D place that is not efficient, The plane can be fun as it's extra power will give you acceleration on the ground.

At the top end of efficiency you need detailed and clean design, flaps retracts and C/S props. You need to be seeking 145 knots OTA and things are getting expensive. A jab 230 is about118 knots from my recollection not from a book but (landing) the over the fence speed at max wt is at the allowed limit. Nev

[skippydiesel]

My craven apologies Nev, got to take you to task again.

 

Ref: "You can "power" your way to higher cruise speed but it's increasingly wasteful of fuel as you are getting into a L/D place that is not efficient..."

You are of course correct but moving the "goal posts" with your introduction of the "power" comment .

 

I am an admirer oft Robyn Austin (Sonerai World Record Plane - Robin Austin who )proved beyond any doubt that amazing performance can be had from an aerodynamically well constructed/designed air-frame, without the need for more power.

[Blueadventures]

So I abbreviated a very little - my apologies.

 

The Faeta stalls at 28 knots, the Faeta NG at 30 knots, the Zephyr at 32 knots - all single pilot. Naturally you must increase speed with load (additional person) so add about 3-5 knots. You should also consider variation of air density altitude, wing cleanliness, As with all aircraft, these figures, while achievable in most situations, will vary slightly between individual aircraft and must be considered indicative and best kept above, particularly when close to terrain.

 

I stand by the above and am happy to arrange a TIF for those who are genuinely interested in discovering the truth/fact.

 

The hard reality is there are a small number of (RAA type) aircraft with a genuinely wide operating envelope. The rest ,while excellent aircraft in their own right, can not even come close.

 

Most of the ones with a sub 35 knot stall, struggle to reach 100 knots in cruise at 18L/h or worse.

 

For the most part, those that can achieve a 120 knot plus cruise (18 l/h) have stall speeds above 40 knots - some are struggling to remain within RAA stall requirements.

 

(Rotax 912 ULS fuel consumption is being used as indicative of energy/power needed to reach the air speed quoted. All air speeds are indicated)

 

My factual point is - for about 20 years now, there have been available RAA aircraft that seem to defy the old "truisms" about aircraft being fairly limited in their flight envelop. In the past (and certainly what I received in training) the pilot must decide does he/she want low/slow/STOL or high cruise and high stall long TO/Landing characteristics. Supposedly you cant have both.

 

There is no secret to this capability - As Nev has pointed out, clever wing design coupled with efficient flap design ,allows for wider flight envelope .

 

That the above facts, still seems to cause consternation and denial with the old guard, is to me absolutely gob-smacking but there you go, we are all entitled to our opinions.

Thanks Skippy. I’m still keen form your info about the MTOW of the factory and kit builds (121), are they for example 450 / 540kG ? Also what is your aircrafts Empty Wt, MTOW and max fuel capacity. Also what is the demonstrated stall speed two up at MTOW, say 540kg. A mate up here has one just north and when flying again I’ll take up a fly.

[facthunter]

Another quote out of context skip. Unhelpful if we seek truth. I was referring to draggy planes and even supporting your concept of clean designs IF you read it carefully. Nev

[skippydiesel]

Thanks Skippy. I’m still keen form your info about the MTOW of the factory and kit builds (121), are they for example 450 / 540kG ? Also what is your aircrafts Empty Wt, MTOW and max fuel capacity. Also what is the demonstrated stall speed two up at MTOW, say 540kg. A mate up here has one just north and when flying again I’ll take up a fly.

 

Both models of Faeta are "rated" to the Australian max TO weight of of 600 kg. All existing Zephyr's in Au are 544 kg. A new Zephyr has not been imported for quite a while, so while I believe this model would also be 600 kg. my partner in the business thinks it will remain at the European 544 kg until an increase is requested (at import) - we will see..

 

The two seat ATEC's are all aground 300 kg empty (my Zephyr is 297 kg) but each aircraft will vary according to fit out.

 

Fuel capacities range from a nominal 60L -100L - you nominate what you want at time of purchase. The Zephyr is limited (at this time ) to a max of 80 L in fuselage. The Faetas go up to 100 L in 2 x 50 L wing tanks.

If you are looking for more fuel capacity,may I suggest an in flight transferable bladder, such as the Turtle Pack.

 

Stall speed (two up with full flap) will vary for each model 122 Zephyr 35 knots @ 450 kg, 321 Faeta 321 28 knots @ 472.5 kg. 321 Faeta NG 33 knots @ 472.5 kg

 

I believe the the aircraft you are referring to, based at Gladstone, is the T tail Faeta. This aircraft has been fitted with a glider tow system, which includes a three (long) blade propeller optimised for this duty. For best all round performance (especially cruise), the two blade is recommended by ATEC.

I recommend:

1. Down loading the POH - read 2.2 Air Speeds & 4.8 Descending & Landing. Take special note of all relevant air speeds and apply-

2. First, at safe altitude, practice landings, so as to gain confidence in the aircraft's slow speed handling characteristics, which for some is initially unnerving but you get used to it. Remember to use more rudder, in preference to ailerons, when practising slow flight.

3. Then on landing apply POH speeds & altitude experience.

[Paulmilo]

Hi Blueadventures - I have some concerns about, what I consider, to be your Jab/parochial view.

 

Don't get me wrong I am an admirer of the Jab fleet BUT your view of what is possible at both ends of the flight envelope is just incorrect.

 

There are RAA aircraft that can demonstrate a stall of 28 knots and a cruise of 135 knots (75% power/18L/h), same day, same engine, same load conditions,

 

Out curiosity - aircraft model?

[skippydiesel]

Out curiosity - aircraft model?

Faeta NG - located in the Hunter Valley NSW - for photos go to Faeta

[Bruce Tuncks]

One of the few crashes we have had out of Gawler was a stol type plane which was doing a practice slow approach ( 40 knots). Unbeknown to the pilots, a seabreeze tendril caused a sudden tail-wind to appear from nowhere in the last 100 feet or so. The effect is much greater with an initial low airspeed... a sudden removal of 20 knots is catastrophic if you had 40 knots to begin with, much less so if you started with 60 knots, which is what I approach with in a Jabiru.

[Bruce Tuncks]

You can get better performance with money. In particular, you can have a cantilever wing from carbon instead of a glass wing with a strut. The cost of this is about $50,000 more. Just compare a CTLS with a Jabiru. The weight of carbon cantilever is more than a strut/glass wing, but not by much.

But for some of us, the performance per dollar really matters and the Jabiru suits me. I would find it difficult to justify spending twice as much.

[Kyle Communications]

So whats the current sell price of a new Faeta in Aussie dollars delivered to Brisbane...since we are talking dollars per perfomance?

[Kiwi]

Faeta NG - located in the Hunter Valley NSW - for photos go to Faeta

 

But not at MTOW "Faeta NG 33 knots @ 472.5 kg"

What is the stall speed at 600 kg?

[biggles]

But not at MTOW "Faeta NG 33 knots @ 472.5 kg"

What is the stall speed at 600 kg?

 

‘Published’..... 37 knots @ 600 kg.

[Kiwi]

‘Published’..... 37 knots @ 600 kg.

 

Thanks, it's a bit confusing with SD's post.....

"Stall speed (two up with full flap) will vary for each model 122 Zephyr 35 knots @ 450 kg, 321 Faeta 321 28 knots @ 472.5 kg. 321 Faeta NG 33 knots @ 472.5 kg"

[skippydiesel]

Thanks, it's a bit confusing with SD's post.....

"Stall speed (two up with full flap) will vary for each model 122 Zephyr 35 knots @ 450 kg, 321 Faeta 321 28 knots @ 472.5 kg. 321 Faeta NG 33 knots @ 472.5 kg"

Hi Kiwi - apologies for any confusion.

The figures I have quoted are from the ATEC POH for each aircraft.

As a European manufacturer they focus on their standards which are as I have posted.

It not so hard to work out that the stall speed incenses with weight - you can do your own 600 kg estimate.

 

I am not totally reliant on the ATEC factory for data - I fly a 20 year old Zephyr, its stall speed is seems to be a little lower than the POH. My partner, in selling ATEC aircraft, has a near new Faeta NG - again he reports a real world stall a little lower than the POH

[Kyle Communications]

So now we know the price..well when that version of Sport Pilot was published in April 2018...most likely higher now due to the dollar as back then the Euro was about 0.65 its now 0.60

 

As the snipet says thats a lot of dollars per knot...not so much if in a syndicate of course and that is probably the best way to get into one. Then again even a factory built savannah is now about 120k I think. If you want a factory built RANS S-21 by the time you get it here and flying it is not much change out of 240k...Blackshape Prime is about 300k too....it makes building your own very attractive

 

Edited August 30, 2020 by Kyle Communications

[RFguy]

BACK TO THE CONCEPT. I stirred quite a argument with this topic, didn't I ?

 

yes the ATEC planes look fantastic, as long as you are in clean continental european laboratory air.

 

Faeta . This on paper is an amazing airplane :

 

and the POH is very detailed on Manoeuvre and Gust Envelope etc for all weights and speeds.

This presumably comes out of their fancy CAD and modelling programs. page 13 etc. POH

The designers know LOTS about this airplane. There is HEAPS of detail.

 

Va = 85 kts IAS (no weight specified against this number?)

Vra = 96 kts IAS "max speed in turbulance"

typical cruise 110-120 kts

Vc = 134 kts.

The Gloadings are quite high compared to similar ACFT.

 

However the devil is in the detail ! weight needs to be specified for those Va and Vra since those numbers FALL with reduced ACFT weight .

 

Compare to little Jabiru J120

Va : 102 kts IAS (@MTOW 500kg). 85 kts at 350kg

typical cruise : 100 kts IAS

Vc : 112 kts IAS

 

so if you are reasonably heavy, Va and typical cruise are similar so no biggie. hard to get into trouble

and I dont hear about too many wings or engines or tails falling off Jabs (until they collide with terrain).

[skippydiesel]

Kyle & RFguy -

 

Dexters Faeta NG is fairly well "optioned up" (higher cost) It is also the more expensive of the two Faeta models.

 

The Faeta V specifications quoted - All are conservative and are at max Euro weight standards, except where specified otherwise.

 

As for typical cruise; Dexter likes speed, he cruises at 130-134 knots (indicated) where ever he goes - I believe at 53- 5400 rpm for 17-18L/h fuel burn.

 

I notice you focused on the upper end of the flight envelope - dont forget that having great low speed handling and reasonable sized wheels will make for stress free arrivals and in the unfortunate event of a crash more likely to walk away.

[David Isaac]

Kyle & RFguy -

 

Dexters Faeta NG is fairly well "optioned up" (higher cost) It is also the more expensive of the two Faeta models.

 

The Faeta V specifications quoted - All are conservative and are at max Euro weight standards, except where specified otherwise.

 

As for typical cruise; Dexter likes speed, he cruises at 130-134 knots (indicated) where ever he goes - I believe at 53- 5400 rpm for 17-18L/h fuel burn.

 

I notice you focused on the upper end of the flight envelope - dont forget that having great low speed handling and reasonable sized wheels will make for stress free arrivals and in the unfortunate event of a crash more likely to walk away.

Yeah ... Dex is a bloody rev head ... always out in front of the pack ... God love him ... LOL

[RFguy]

From a purely physics POV, I would like to have greater ratio of my own airspeed to the wind speed.

 

What I now realise is importance of correctly chosen over the fence speed, for the aircraft configuration.

 

and that you cannot , without difficulty, (at least from my POV) fly a slow airplane (say stall=27 kts) fast (say 45 kts) over the fence. It just isnt going to want to land. the thing is still producing plenty of lift and not much drag , (note : My views are inexperienced and simplistic. )

[turboplanner]

From a purely physics POV, I would like to have greater ratio of my own airspeed to the wind speed.

What I now realise is importance of correctly chosen over the fence speed, for the aircraft configuration.

and that you cannot , without difficulty, (at least from my POV) fly a slow airplane (say stall=27 kts) fast (say 45 kts) over the fence. It just isnt going to want to land. the thing is still producing plenty of lift and not much drag , (note : My views are inexperienced and simplistic. )

Your early lessons will show you how to get your airctraft to do what you want.

When is the exciting day?

[RFguy]

Hi Turbs

the exciting day. I have no idea when that will be . I can problably not break the plane in smooth angel air. I learned what a baloon was yesterday when it got a bit gusty.

It is interesting how confidence with particular manouvers ebs and flows . I thought my finals were getting pretty good yesterday until the wind came up.

 

One of thing things I realised. if a cascade of things are wrong, rather than geting over focussed, stop and reset, look around, reassess your current flying parameters.

 

An over-focus on one thing will get you ignoring something else to your hazard