RC_Fanatic

My Feedback: (1)

Nice looking airplanes! Much preferable to the "flying guppies" you see today.

Capt. Bill

I am still stuck in the 1980s

roncoleman

My Feedback: (14)

I'm right there with you brother. 70s,80s, and 90s

Ron

MTK

Form follows function

RC YEAGER

Maybe I'm just mistaken as to what is meant by double tapered. To me, double tapered is a wing which decreases both in chord and thickness as it progresses toward the tips. It is clear to me, both in the photos posted here of the Vagabond and the photo in the Bluejay site that the wing is like just described. If I'm wrong, will someone please explain to me what is meant by double tapered?

MTK

LE tapers aft and TE tapers fore. Thickness is typically not part of the equation but it might be considered....if thickness reduces in percentage, the wing may be thought of as triple taper

My favorite wing design I described in the thread Few Ideas To Chew On, is indeed triple tapered. It flies better than any pattern wing I've ever flown especially in crosswind.

Capt. Bill

You are correct but my Vagabond is only chord tapered.

RC YEAGER

Okay; that is what I thought would be the only possible interpretation. I'm not saying its wrong, in fact I can live with it, but back within my group of RC buddies we call a wing which shortens in chord towards the tip a double taper wing, regardless if its joined/mounted with one of its edges straight, mostly because you can use a specific wing platform and depending on the designer's intention, he can cut and/or angle the root (think foam wing, although same applies to built up wings at the planning stage) so that when both wing halves are joined, the LE may be straight and the TE swept forward, the LE may be swept back and the TE straight, or any mixture in between or beyond (i.e. both edges tapering inwards or both swept back, etc.) In a nutshell, according to your definition of double tapered, a person can take a tapering wing which shows a straight TE and make it double tapered by simply re-arranging the angle at which the wings meet at the root, without doing anything else to the platform. So you see, that is why to me, once a wing tapers chord-wise it is automatically a double tapered wing, even though in practice it might be used in an airplane to make it "appear" as single tapered (as in straight TE - swept LE).

RC YEAGER

Really? Wow! Have never seen that before. The airfoil at the tips most be really roundish and stubby, if the thickness does not decrease in % as the chord shortens.

RC YEAGER

This is why I love this hobby; one is always learning new things

Capt. Bill

Found a picture of my Vagabond before covering. This should clear things up

RC YEAGER

Great picture. It is clear the TE is sweeping forward. The angle of the plane in relation to the camera disguises a little bit the fact that the leading edge is swept back just slightly. This can be seen better in the plan spread out bellow the plane. So... yes its tapering chord-wise. As to the thickness of the ribs (height) it seems to be constant at the max point but when I view it in extra zoom, it appears that the width between the top and bottom spars increases ever so slightly as one looks at the ribs going inward; this makes me think that it is tapering in thickness too. Sorry! Don't want to be stubborn. If you say the wing does not get thinner towards the tips I'll just take your word for it. If so, the airfoil at the tips winds up being something entirely different from the one at the root, however slightly (curvature change).

RDJeff

My Feedback: (11)

I'm new to this, and just dipping my toe in the Kaos waters. I have a Kaos 90 short kit about halfway built (just started a few days ago), a Super Kaos short kit that will get built soon, a Kaos 40 that will also be built soon, and just for fun, I took the Kaos 90 plans to FedEx, and had them shrink them to 50% so I can scratch build a small Kaos. I'm thinking of giving all four of them the same paint scheme, just for grins.

RC YEAGER

Wow! you'll be busy! when you finish all of them take a photo and post it.

Capt. Bill

OK, just looking it is hard to tell but I used a sliding clap as a caliper and the Vagabond does have a slight rib taper.

RC YEAGER

Okay... Seems more logical to me than just chord taper. Having said that, I now wonder if some designs do use just chord taper. Maybe a few of the 1960's designs (of the Reb, Taurus and such era), some of which I remember noticing some "strangeness" in their airfoils, as if their airfoils were becoming more "rounded" towards the tip.

vertical grimmace

My Feedback: (1)

The tip thickness reduces if the same airfoil is used. So a double tapered planform by it's nature has a thinner tip section. If it is the same thickness as the root, then it would essentially have a different airfoil. Historically, when designing a tapered wing, the tip section is a percentage of the root. The whole airfoil is reduced by that percentage. Otherwise, you would have say a 15 % root airfoil, and like a 22% at the tip to make them the same. That would be a very uncommon design.

RC YEAGER

I concur 100%... Another thing I HAVE seen (and this is a completely different animal) is designs that use different airfoils at the root versus the tip, and the airfoil smoothly transitions from one to the other along the span (from the use of wire cutting in foam wings and the sandwich method for ribs).

MTK

Yeager, I think you are correct. The easiest planform to see the taper is the one where the TE tapers fore and LE tapers to the rear, where the tip chord is a fraction of the root chord. But there are many possibilities, some with straight LE, others with straight TE. These latter planforms are swept, some fore and some aft.

VG, thickness doesn't have reduce toward the tip. Two inches thick at the root and tip can be built just don't know to what end. Most designers opt to keep the percent thickness pretty close to constant which means thickness will taper towards the tip.

RC YEAGER

Good observation

vertical grimmace

My Feedback: (1)

Almost all full scale designed aircraft have thinner wing tips by percentage than the root. It is more efficient that way. If you look at most warbirds, they have around a 15% root, and a 9% tip percentage. These are 2 different airfoils.

While a tip and root that measure the same is possible, It is rarely seen in model design. A typical technique in pattern design is to build the wing flat on top, and have the corresponding taper on the bottom of the wing create the dihedral. If I remember correctly, that is what is done with the Killer Kaos.

The Kaos wing is an 18% airfoil, and the tip is like 65% of the root, chord. So essentially when designing, you take your full scale root airfoil, and reduce it in your copier to reach the chord dimension you want. So the thickness is thinner, but relatively the same to the root. Both 18%. 18% of the chord.

When the high point (thickest part) of the airfoil is moved aft at the tip, relative to the high point of the root, this is called sweep. If it is moved forward, it would be forward sweep. So just because the leading edge tapers back, that would not be consider sweep, unless there is a movement of the high point. The amount of taper, is determined by the width of the tip chord. Generally not a good idea to go under 50% as you can have tip stall issues.

MTK

Talking big Kaos, this model has the thick foil. Wing span is sizable as is area. It also has a rather short stubby fuse, at least my kit does. Fuse length is about the same as the 60 size model which was quite a surprise when I opened the box. At minimum the fuse will be lengthened to be similar to its span.

I intend to reduce wing thickness and convert the wing and fuse to plug in. There's a lot of unnecessary weight in that kit and much will be removed. I expect a 13 pounder with a 40cc twin up front on twin pipes.

roncoleman

My Feedback: (14)

Vagabond 40 plan.

Capt. Bill

Here is a question I wonder if anyone can answer. The Kaos 40 sized plane has gone through three incarnations. The Bridi kit called either the Super Kaos 40 or Super Kaos Jr., the Tower Hobbies Kaos kit (out of production) and the Tower Kaos 40 ARF. Has anyone had a chance to compare all three planes in flight? Joe Bridi sold the rights to the name Kaos to Tower. I do know the Tower kit has a wing span of 60" and the ARF is listed at 55". Joe Bridi's Killer Chaos is listed as a 60 size plane and it's wing span is 62.5". The Bridi Kaos 40 had a wing span of 52"

Falcon6667

I have flown most all of Joes birds, an for my flying style since 69,they are all great, an fly very similar. Here is my Sunfly 4..