The 250-class landscape is both barren and littered with trash.

Everything is built for "professional crashers". Basically, guys who brag about how much they crash. Or guys who brag about guys they know that crash a lot. As if vicarious crashing somehow makes a compelling argument for trashy design.

There's nothing out there that's built for more reasonable people. What if you don't want a quad pretending to be a basher truck? What about something that is light but functional?

Well, you get nothing. You are forced to design and build your own.

So that’s what I’ve been doing on the side. I started by picking up a few frames to take a look at, one of them being a Dart 250, which I immediately noticed a number of problems with.

All the software tools involved are free; I’ve been using OpenScad for the 3d parts and rendering, DraftSight for some of the more annoying 2d stuff, and the occasional Meshlab for manual checking. All of this runs under Linux.

This is what the design currently looks like in rendered form, and in subsequent blog posts I’ll go into different parts of the project.

I’m just calling it the Tard 250 as a tribute to fine design acumen of the manufacturers of typical 250 class quads.

So I've flown my multirotors literally all over town now.

Even flew my multirotor at SXSW Create, right in the same airspace as the big boys. The Make folks seemed quite happy to have me.

Make SXSW Multirotors 1 (3 min 18 sec)

Make SXSW Multirotors 2 (3 min 30 sec)

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Took my Stryker out for its first flight with the GoPro HD Hero yesterday. The camera was originally purchased for scuba use, but I figured I might as well throw it on a plane as well since it's only 3.3oz and takes pretty good video.

I should really retire this Stryker (it's still my first Stryker frame), but its replacement isn't built yet so it's still going to get some action. This plane is all about the no-frills-get-the-job-done approach.





A couple of still frames from the 1080p video:

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I've come to the realization that what I've been intuitively experiencing is a real phenomenon as opposed to my imagination, and not only that, but it's a fact that's been overlooked by RC modelers for a very long time.

I've been maintaining a light built flying wing, like a Stryker, is a perfectly good plane for a beginner. Conversely, the conventional "trainer" designs (that is, anything labeled as "trainer") are actually garbage.

Usually the first two counter-arguments are "you need to have dihedral or be high wing for [insert some vague notion of centering]". This is because most of these trainers at least have a high-wing design, and some also have a dihedral/polyhedral.

But a light Stryker seems to be pretty stable and has something similar to this [vague notion of centering] without being high-wing or having a dihedral. What's going on?

As it turns out, if you spend 5 minutes looking at "dihedral effect", you'll find that it affects the "sideslip" of a wing. And you'll find that many other factors affect this same thing...

... including wing sweep (backward).

So assuming similar wing loadings, which plane would you rather hand to a beginner? It's important that beginners actually get out and get stick time. Well, what grounds beginners more than anything else?

Wind.

What design presents more problems in wind? A plane with a dihedral in the wings and a big clunky fuselage hanging under it, along with a...Continue Reading

This is an adjunct to my trainers post.

It's also pretty media intensive, so I've moved all the links to a comment in this thread so as not to cause difficulty with RCGroups's main blog page. Sorry about that.

Stub until I fill in the text.

Meanwhile look at some pictures.

It seems to me that, in keeping with the standard delusional behavior, there seems to be a general concept amongst RC modelers about what constitutes a good trainer.

And what exactly is the criteria that they make this judgment on?

"It looks like a trainer."

That basically sums up the reasoning. If it kind of looks like a trainer, then hey, that'd make a good trainer.

What I plan to do is actually make a list of criteria which I think are necessary for a trainer, and then I'm going to list a bunch of common planes and apply the criteria.

1. Stable flight. The plane has to have reasonably stable flight characteristics.

2. Low wing loading. Let's say no more than 7oz/sq ft.

3. Pusher design. Yes, this is a requirement, above and beyond some of the later ones I am listing. If the prop/motor/gearbox is in the front, then you are pretty much guaranteed some form of prop/motor/gearbox damage in a crash. It's as simple as that.

4. Durability. It needs to be able to tolerate some rough treatment gracefully.

5. Low parts count/minimum amount of specialized parts. More parts mean more parts to break. Specialized parts mean you need specialized replacement parts when they break.

6. Some ability to cope with wind.



There may be a 7th criteria -- build difficulty. I tend to think that this is somewhat encompassed in #5 -- after all, how hard can a build be if there aren't that many parts to begin with?



So, let's look at some common "trainers".

I agree whole-heartedly with most of the people in this thread. I hate everything Chinese. I hate Chinese products, Chinese food, and Chinese people. American imitations are OK, but Chinese ones? Man, those just get my blood boiling.

What a wonderful thread. I see threads and statements like this in RC all the time, and it's just wonderful to see this sort of thing; it's like the greatest minds of our society flock to this hobby. Top notch stuff.


The original guys need to run to the patent office(s) and patent that bag. Let's put the "intellectual" back into "intellectual property"!

...

I just saw something in the Electric planes forum that gave me a chuckle.

The worst problem RCGroups has right now is rampant lying and deliberate misinformation.

People just say things that simply cannot be backed up, or are flat out untrue. What's worse is that this behavior is encouraged by others.

This behavior, in the end, only hurts our hobby.

"Just remember, it's all in fun" is usually the dying battlecry of someone on the wrong side of a fact-based argument. Since when has deliberately misleading others constituted good clean fun? As long as you cap off a lie with a , it's perfectly acceptable?