Safety (Lack of injury and death) is my prerequisite and priority

[Jethro Belle]

Why worry.....Just do a go around !

You are, of course, correct Butch.

 

The report link in #172 emphasizes 46% of LSA accidents are RLOC and my original desire was to end up flying a very 'slippery' high speed fuel efficient touring aircraft, which by my reckoning rates it high on the RLOC risk.

 

In some circumstances going around may not be an option: In forced landings ... I can also see that generally good pilots that are part of the 46% have committed and it is too late to go around, or presumably they would have. I can envisage turbulence/wind shear situation that such devices correctly used may provide an advantage.

 

While flying skill can be increased, it cannot fly an aeroplane beyond its limitations. If greater control is available, especially if it makes it easier for the pilot, that is a good thing. I am speaking from my humble opinion based on my engineering background, not claiming manufacturers or pilots are wrong in their current practices. Probably such capabilities are not common due to additional complexity, weight, failure modes and difficulties with their operation causing a greater risk, but given the statistics, if something could help in addition to pilot skill it would be good.

 

I have flown with people who side slip to loose height to get into a strip. Simplistically a more direct way to add drag would seem safer.

 

I have placed 'effective flaps' on my list of requirements and ruled out flapperons

 

 

[facthunter]

The nut that holds the joystick is the main cause of injury/death. Don't over complicate the matter with flaps ( seeing them as essential on simple (basic) aircraft. They contribute weight complexity and cost . also if you have an asymmetry problem it's another quite serious, hazard.. As for fast planes ( that DO need flaps) Speed at contact is the energy thing (V squared) less headwind component, relating to damage injury. Being able to exit is important post incident..

 

Statistical information is not the easiest thing to interpret. You have to filter out the dross. and irrelevant issues. Component reliability is as important as the core engine is. An engine failure should not kill you if you manage the associated risks (where you fly) and are ready to manage it skills wise and you plane has good controllability. down to slow speeds) Flying is not for over relaxed people or at the other end nervous nellies who really are constantly scared but hide it. Manage (Choose) the weather you fly in. You usually can. Taking off is rarely an absolute necessity.. Service and inspect your plane well. That isn't sissy. . Nev

 

 

[Jethro Belle]

I reckon the Citabria 7 ECA I owned would get into most what people would call "short" strips

Thanks Nev, I looked up the Citabria 7 ECA. A nice plane and easy to fly judging by the Harloff Performance Factor

 

for the Citabria Adventure (150 Hp version). I notice the later Citabria Explorer had flaps! More power, more weight, more speed, more need to get lower landing speed.

 

In case you haven't come across it "the Harloff Performance Factor, is employed to quantify airplane flyability for low-time to high-time pilots". A

 

low number indicates an easy to fly airplane for low-time pilots. Harloff is a brave man, covering carnard pushers, amphibians and STOL by his factor. He developed it from the rating system given in "Design for Flying" by D. Thurston 1995

 

Harloff Performance Factor = climb rate (ft/sec)/100 – [computed roll take off (ft) +computed roll landing (ft)]/200+ 4 [umax cruise/Ustall-1] + max L/D + 5 [HP/HP min required for level flight]

 

I have cut and pasted a few examples for your recreation (HPF are the last number).

 

Adam A500 dual boom 15

 

Stinson Station Wgn 16

 

Piper Arrow pa28 27

 

Cessna 172 19

 

Citabria Adventure 33

 

Jabiru J250 30

 

Flight design Ct 31

 

Piper seminole PA-44-180 34

 

TL Ultralight Sting Sport 34

 

Zodiac CH601XL Jabiru3300 34

 

Skykits Savannah 37

 

Zodiac Ch701 34

 

Zodiac CH601XL Rotax912S 37

 

Beech Bonanza J35 36

 

Cirrus Sr22 38

 

Mooney M20J 38

 

Rv-9 135 hp 38

 

Jihlavan Ap KP5 Kappa 41

 

fantasy air Allegro 2000 41

 

Gannet Freedom Amphib 42

 

Rv-9 160 hp 43

 

Sonex Xenos-120hp Jabiru 45

 

Berkut 360 48

 

Lancair Legacy 50

 

Glassair III span=27 ft 46

 

Berkut 540 57

 

Lancair Propjet 73

 

STOL seem to rank higher in flight difficulty than I would expect!

 

The full pdf explaining it and including other planes can be obtained at

 

https://www.researchgate.net/publication/259739308_Light_Sport_and_General_Aviation_Airplane_Comparison_and_Harlof

 

f_Performance_Factor

 

I am interested to hear if you think his single number ranking has any merit in assessing aircraft. From my limited knowledge it ranks in a sensiblish order, but needs to be qualified with aircraft specific information, strengths and issues for decision making.

 

 

[facthunter]

The concept of a difficulty index is sound and I can't see anything much I would disagree with at a cursory look. Experienced pilots tend to underestimate the difficulty SOME pilots have with tailwheelers.. You should neither over or under emphasise that aspect but it IS "different "and even "docile" tailwheel planes can catch you out if you are a cowboy and take them for granted. GOOD flaps have a big effect. like the Cessna FOWLER types and those on jet transports.. Some "simple" ones are a more effective brake than a real stall speed lowering exercise . STOL planes are difficult in some situations as the gusts are a higher % of their slower speeds and therefore have a bigger effect on their margins. Usually require an "active rudder" type of handling as well and use of throttle. Nev

 

 

[johnm]

interesting some of the indexes

 

Lancair Propjet - index 73 .......... best in the list

 

 

Cessna 172 - index 19 .......... a puppy

 

 

Sonex Xenos-120hp Jabiru - index 45 - must have bite

 

 

Jabiru J250 - index 30 - looks OK

 

 

Skykits Savannah - index 37 - looks tame

 

 

fantasy air Allegro 2000 - index 41 ................. got some teeth

 

 

 

[crashley]

I have flown with people who side slip to loose height to get into a strip. Simplistically a more direct way to add drag would seem safer.I have placed 'effective flaps' on my list of requirements and ruled out flapperons

Why no flaperons and what is wrong with sideslipping

 

 

[Jethro Belle]

Lancair Propjet - index 73 .......... best in the list

I agree John, but it is hardest to fly according to the HPF index and hence my interest. What I think are 'better' planes for me IMHO are all 'harder' to fly I am sure I am not alone in this. A lot of flight school ahead for me:cheezy grin:

 

I always had a Jihlavan Ap KP5 Kappa on my radar. It ranks the same HPF as the Fantasy Air-Allegro which surprised me a little.

 

 

Image source: Kappa KP-5: LSA With A Difference - Plane & Pilot Magazine

 

I was told it was a handful when I first considered it and a HPF of 41 suggests there are easier planes to fly, but to me the Allegro looks easier to fly (superficial assessment based on configuration). Their performance specs, ignoring range, are comparable so that is how the HPF stack up.

 

That is why I asked experienced pilots for feedback about the HPF reliability in predicting easy piloting. Using the HPF as one metric to guide my aircraft purchases would avoid my misconceptions. I take it from your post you agree with the HPF rankings.

 

Yes Nev. A flipped KP5 would be hard to exit Their spindly undercarriage are reported to be far tougher than they look.

 

PS: Gary Harloff seeking feedback on his factor, so if reply posts justify I will notify him or you can do it directly in person on the link I posted in #178

 

 

[Jethro Belle]

Why no flaperons and what is wrong with sideslipping

 

I have read somewhere (I can't find the ref ) flaperons are harder to fly, or more sensitive to asymmetrical effects (see @facthunter post #173). I was not suggesting my decision should apply to others. Your post indicates my perception is wrong. I would appreciate corrective replies, which is why I mentioned my decision. What is your experience and opinion? I am sure flaperons work well enough. In engineering design, combining two functions into one is good practice, if it does not compromise functionality, but what I read indicated it was a compromise made for physical simplicity. IMHO better to have flaperons than no flaps, but that will probably draw flack for others :duck for cover:Nev doesn't see flaps as essential, but planes like the Jihlavan Ap KP5 Kappa have them, providing good cruise speed while achieving low stall speeds! Perhaps I should have worded it, that for me, my aspirational plane must have high performance flaps (or equivalent), but I may buy a cheap slow flapless 'drag bucket' to build up local flight hours first (My first post was shorter).

 

It was the person doing the side-slipping that made the comment, and he was the CFI and a very good pilot with experience that would run rings around most. I just took it as given without questioning. I couldn't see anything particularly wrong with it at the time, even though controls are crossed up (This link may be relevant). It could have been that it is was not recommended for beginners, because it subverts the need for a correct angle of approach. From my engineering perspective it is pilots using a work around to achieve something a plane wasn't specifically designed to achieve (please no more ). I can see it is fun, clever, and am not criticizing anyone doing it. It underscores why I have been discussing 'airbrakes' (Just explaining my rationale, not reopening that please. I've gone with effective flaps.).

 

Out of interest the HPF for your RV 12 is 30. That indicates it should be an easy to fly aircraft.

[dsam]

My Eurofox has full length “junkers style” flaperons. Fully deployed, I find they provide excellent STOL capability (< 200 metres @MTOW) and excellent manoeuvrability at slow speeds - particularly helpful with turbulent conditions during landings. Their main drawback is low-speed adverse yaw, but as a former glider pilot, this is something I take in my stride; my rudder-stick coordination is embedded in my technique. I find I compensate without really thinking about it. Some say the positioning (always being in the airflow) leads to unnecessary drag in the cruise, but I never find this a problem either. I easily manage a TAS of 110 knots @ 18 lph (Rotax 912 ULS)

 

 

[facthunter]

That set up works very well. Some other designs have quite marked need for BIG rudder flying. People not trained properly can get into strife. A flap does one thing an aileron does something else. Differential ailerons are the norm (more UP than Down). Flapperons lose some of that feature . when flap function is fully applied. Nev

 

 

[Jethro Belle]

My Eurofox has full length “junkers style” flaperons. Fully deployed, I find they provide excellent STOL capability (< 200 metres @MTOW) and excellent maneuverability at slow speeds - particularly helpful with turbulent conditions during landings. I easily manage a TAS of 110 knots @ 18 lph (Rotax 912 ULS)

Thankyou for posting. It confirms my perception that flaperons are well suited to 'slowish' aircraft with STOL type capability. No criticism of this type, it is just not my inspirational 'slippery' touring aircraft flown from good air strips.

 

Your Eurofox looks like a safe CrMo fuselage aircraft similar to what was being recommended for me and at cockpit 112cm is 10cm wider than a Cessna 172! A nice comfortable place to be. As a fun local aircraft it is on my radar.

 

 

source: Aeropro EuroFox - ByDanJohnson.com

 

 

Source: Why was the engine of the Ju-87 Stuka not replaced with a more powerful one? (and quote below)

 

"The airplane had a lower wing loading than fighters, had the very effective Junkers Doppelflügel (offset flaps) and could turn much better, so it was not easy to shoot down. The downside was an inherently higher drag which could not be overcome with a bigger engine (which would had made the aircraft heavier).

 

My take is "Doppelflügel" provide slotted/Fowler flap type performance at the expense of more drag, and massive ailerons to boot. Also much simpler to implement and inspect.

 

Your cruise speed intrigues me because Eurofox - Aeropro (and other sites) quotes 185 km/hr Maximum Speed (100 knots)! How are you achieving this speed? What altitude do you fly?! I am looking for 120 knot cruise (eg: even Jabiru J230-D. Cruise Speed: 120 kts can do this) which would require about 170 hp in your aircraft ignoring Vnc.

 

 

[dsam]

Jethro, my Eurofox is the Rotax 912ULS 100 hp. 3k model (trike) with smaller wheels & pants. It is available with variable pitch propeller, so that is how one gets that sort of TAS in the cruise - note photo where I am nudging it along a bit :-o

 

I find that the "sweet spot" cruise altitude is around 5500 ft. with the Rotax carbys. My POH states a Vne of 116 KTAS and with full flaperons deployed it slows down to a Vso of 39 KTAS for nice short-field ops (MTOW 560 kg.)

 

This 100 hp. version is used to tow gliders up to 750 Kg. At Tocumwal they use the Eurofox glider tugs with a taildragger configuration, with exposed balloon tyres for paddock recoveries. Naturally, that leads to a slower cruise TAS when not towing.

 

As for "local touring" from Melbourne, I've flown mine across to Tassie, up to Birdsville & over to William Creek, Lake Eyre etc. and I've been happy with all of this. The 2 axis Dynon Skyview autopilot helps with the longer legs. Even better, on return I stow my Eurofox with the wings folded back in a car trailer, so no home hangar fees!

 

 

 

 

[turboplanner]

The massive drag on the Stuka was primarily the multiple bomb load it carried into attack

 

It's slow speed was solved by the strategy of coming into the target range very high, then diving almost vertically down on the target.

 

 

[Jethro Belle]

on return I stow my Eurofox with the wings folded back in a car trailer, so no home hangar fees!

 

Certainly a very nice plane well set up @dsam and it has gone up in my assessment. Being able to trailer is a great bonus that make up for a slightly lower cruise speed IMHO. I am impressed at the performance you are getting, and surprised they undersell it on their site http://www.aeropro.sk/eurofox/ which gives Economical speed = 120 km/h! (about half the cruise speed I was pursuing) and a Vmax of 185 km/h! Yes, I know cruise speed is higher than economical speed for those who may bombard me.

 

Shows how difficult generalizing and decisions based on 'average' can be.

 

Flaperons reduce the number of linkages on a folding wing = another bonus and safer:cheezy grin:

 

Sorry about Vnc, I meant Vne. I use VNC on computers too much

[dsam]

Certainly a very nice plane well set up @dsam and it has gone up in my assessment. Being able to trailer is a great bonus that make up for a slightly lower cruise speed IMHO. I am impressed at the performance you are getting, and surprised they undersell it on their site

Jethro, FYI the Australian importer & supplier for the Eurofox is Horsham Aviation in Victoria:

Horsham Aviation Services Aircraft Sales

Have a look, and if you are interested or have further questions, give Tony Brand a call about a custom configuration for you. He is extremely knowledgeable about GA and recreational aircraft. Horsham Aviation is also a major Australian supplier for Dynon avionics that makes my flying so much more enjoyable. As you can see from my Dynon screen-shot earlier, the airborne data display leads to excellent situational awareness at all times - a huge safety factor, IMHO.