The REAL reason to choose high vs. low wing...

[facthunter]

Comment.

 

Most has been covered, but here's mine

 

For light structures the high wing can be built stronger (with the strut in tension) that any cantilever wing.

 

High wing has a definate blind spot in turns. (You can perform a pre-turn manoeuver to get a good look.)

 

In a VERY limiting crosswind situation, you can get the in to wind wing down very low without ground contact as would happen with a low-wing at the same bank angle.

 

You don't run over markers/cones as easily as you do with low wing. ( and you can taxi through gates.)

 

Canopy opening /detachment. doesn't happen with high wing. Door opening in-flight is the same for both.

 

Gravity feed is possible with a high wing.

 

Photography , air to ground is easier with high wing.

 

Parachuting is easier from a high wing.

 

Undercarriage can be mounted easily to very strong parts of the structure with a high wing

 

Climbing on the wing to gain access opens the possibility of damage, and requires extra structural strength locally.

 

Strut is often in the way when getting into high wing.

 

Retractable gear can be more easily adapted to a low wing, and if you were going for out and out performance (speed) the low wing would be the best starting point.

 

Pitch up on go around with lots of flap extended would be less of a problem with a low wing. Nev

 

 

[farri]

Re: my initial Q (and despite its overly rational nature): I'm not asking why people choose the planes they do. My Q is about what significant design feature(s) distinguish one from the other, either for the builder or the pilot. This of course could be just one big snipe hunt (aka: fruitless search) and there is no significant functional difference. Just doesn't strike me as a logical conclusion to draw, however, given how distinctly different one is from the other.

 

 

Hi Jack,

 

I may be lost on this one,set me straight if I am but to my way of thinking,only the designer/builder could explain the reason and the significant design features for their design.The designer/builder would have a specific objective in mind relative to the individual aircraft.

 

It appears to me that regardless of the advantages or disadvantages of high wing versus low wing,they are simply a different way of doing the same thing,which is, flying,therefore we need to look at the individual aircraft design and establish the objective of the design to be able to answer the question satisfactorily.

 

Frank.

[Yenn]

Jack, I think you have a misunderstanding about the definition of LSA. As far as I know LSA aircraft are designed by someone like Cessna or Vans andthey are buile exactly to the design. there is no variation allowed in materials, equipment or design. I think you are referring to Homebuilt or Experimental aircraft, where the builder can design it or buy a design and then modify it, or buy a kit and vary the construction.

 

In Australia the only advantage of LSA over homebuilt is that RAAus will allow 600kg MAUW for lSA and only 550 for a homebuilt landplane.

 

 

[Jack Tyler]

Yenn:

 

"I think you have a misunderstanding about the definition of LSA. As far as I know LSA aircraft are designed by someone like Cessna or Vans andthey are buile exactly to the design. there is no variation allowed in materials, equipment or design."

 

No, I'm looking *across* the entire span of current LSA aircraft, where the designs vary (cantilevered low wing, cantilevered high wing, strut-in-tension high wing), the basic construction techniques & materials vary (composite, stressed skin, tube & fabric and a mix of several), and certainly the evolution of each builder and the designs themselves all vary significantly. So viewed comprehensively, I'm simply trying to understand what inherent, basic and functional benefits (or liabilities) exist for one wing design vs. the other.

 

Perhaps - or perhaps not - a good example is TL Ultralight. They have chosen to build a composite low-wing and a composite high-wing. And not just a single model, but several iterations of each model. Was their motivation to simply fill the LSA pipeline so they can market their product to those of us with both types of wing preferences? The current versions - the low-wing Sting S4 and the high-wing TL 3000 - strike me as being equipped and also being marketed very similarly. So what was the design brief given to the designers by the company's directors? And why? Perhaps I'll have a chance to meet one of the TL principals at Sebring and get closer to at least their set of answers

 

Jack

 

Edit: Oops. Was no doubt thinking of the CT line, a series of strutless, composite a/c. But the basic Q I have for TL remains the same: How were they looking at the concurrent marketing of two different wing designs, and sustaining both design choices by freshening each model multiple times.

 

 

[Guest burbles1]

To quote an Australian example of a builder that is trying different design variations, I can think of Brumby Aircraft, who started with a low-wing trainer. Now they are adding a high-wing model to their range. I don't know why they developed a high-wing - maybe worthwhile asking what their philosophy is?

 

 

[rgmwa]

Jack, I think you have a misunderstanding about the definition of LSA. As far as I know LSA aircraft are designed by someone like Cessna or Vans andthey are buile exactly to the design. there is no variation allowed in materials, equipment or design. I think you are referring to Homebuilt or Experimental aircraft, where the builder can design it or buy a design and then modify it, or buy a kit and vary the construction.In Australia the only advantage of LSA over homebuilt is that RAAus will allow 600kg MAUW for lSA and only 550 for a homebuilt landplane.

Yenn,

 

LSA aircraft are designed by many companies, not just Vans and Cessna. All that is required is that they conform to the performance limitations defined for the LSA category. Basically they are simple, two seat aircraft with a MTOW of 600kg. In the US there is also a maximum sea level speed limitation that doesn't apply in Australia, and we also have a higher permissible stall speed.

 

Aircraft that conform to the LSA requirements can be built either as E-LSA or EAB. If built as an E-LSA, it has to be an exact copy of the manufacturer's certified aircraft. Aircraft built by the manufacturer are called S-LSA's. However a builder can also buy an E-LSA kit and build it as an EAB (provided the kit meets the 51% rule), making any modifications he/she likes, just like any other homebuilt. An E-LSA builder can also make modifications to the plane, but only after it has been certified, and provided those modifications don't take it out of the LSA category.

 

rgmwa

 

 

[Spin]

Suffice to say I see I'm not the only one who doesn't read the preceding posts properly:laugh:. I really don't think Yenn believes that only Cessna and Vans build LSA's

 

Back to something Nev raised - door opening in flight. Now if I read what he said correctly - no warranties, there is no difference between the two? Must say that hasn't been my experience, admittedly I've only had 2 such incidents, 1 in each type, but whereas the C150 (high) closed easily enough, a PA28 proved next to impossible to pull closed, despite varying speeds and slipping toward the door. Admittedly the effect of flying with the door open was similar (minor but noisy and windy). I did a bit of thinking about my experience and later discussed it with an experienced instructor - thinking is that the difference in air pressure between the upper and lower surfaces of the wing accounts for the differing forces needed to close the door.

 

On a similar point, I'll admit to a prejudice against the flimsier variety of tilting bubble canopies, I really don't fancy the possibility of the thing flexing open and been torn off, as has happened before - at least a slider has a fixed roll bar of some description, just ahead of your noggin which should offer some protection, roll-over and by securing the forward portion of the screen in flight.

 

That aside I'm happy to fly aircraft with wings in most configurations - haven't had the biplane pleasure as yet but am hoping to correct that shortly.

 

 

[rgmwa]

Suffice to say I see I'm not the only one who doesn't read the preceding posts properly:laugh:. I really don't think Yenn believes that only Cessna and Vans build LSA's.

Ah yes. That little word '...like...' makes all the difference. Sorry Yenn.

 

rgmwa

 

 

[facthunter]

Door closing in flight.Difficulty?

 

Spin I agree with you that the high wing may be easier to close in some instances. Slow speed and a fair bit of slip helps. The higher pressuure under the wing may also assist. In any case the plane should not crash with the door ajar If the pilot is not too distracted and puts up with the noise and a little bit of extra drag. The BUBBLE canopy going off it's runners/hinges/unlatched, is another matter, being much more of a hazard. I haven't displayed any preference, with high vs low, just trying to point out all the considerations that I can recall. Good discussion. The Biplane DOES have the disadvantages of both, but an open cockpit Biplane is SPECIAL. Often the front cockpit is very hard to access being under the top wing requiring stagger and sweep back ala Tiger moth. I have dropped a parachutist out of one . ( I only did it ONCE, and I think I will leave it at that)....Nev

 

 

[Yenn]

My personal opinion is that high wing is good for load carrying, short field and anything not requiring max speed for fuel use. Low wing is faster and possibly less capabable of doing everything for everyone. I started flying in low wing pipers and finished my training in cessnas and enjoyed every one of them, but i still like the low wing. For aerobatics there are a lot more low wing designs, but Citabria and Cessna have managed to get a toe in. For general bush flying, out of rough strips and negotiating farm gates the high wing can't be beaten, but I am still building an RV4, just because I like the low wing.

 

 

[Bill Hamilton]

Folks,

 

Don't know if it has already been mentioned, but a high wing is great for taxing through gates, a not insignificant advantage in some of the places I have been over the years.

 

Cheers,

 

 

[Jack Tyler]

Thanks for the discussion, folks. My takeaway for now is that, if there is some fundamental benefit of one wing design over the other, those of us here are unaware of it. OTOH we seem to have accumulated a good list of each wing design's pro's & con's.

 

One other reference that I found close to what I was looking for is here:

 

Guide to Biennial Flight Review - MyPilotStore.com

 

Buried in there amongst a lot of wordy chatter, near the end, is a discussion on some of the design implications when actually flying - e.g. when needing to slip the plane when the approach might be hot and/or fast. I hadn't seen that before.

 

I'll revisit this after Sebring, assuming I get over there.

 

Jack

 

 

[FlyBye]

There maybe an argument that in a low wing you sit in the pivot point as the high wing you are dangling below the pivot.

 

point??

 

 

[facthunter]

Pivot Point.

 

Would that be more related to the CofG? With elevators at the rear the pivot point would be forward of it. The centre of lift would have something to do with it too. Rather complicated. ( Just thinking aloud) Nev