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Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Rienk, Aug 1, 2010.
That design won't work, I mean fly.
Ok, I think it's been pretty well established for this to have a chance of resulting in a commercial success (baring a nice confluance of chance events) we need to identify what kind of plane will sell, to whom, and how to market it. If not done before the design actually starts, at least at the same time.
Maybe we can apply our engineer instincts to this problem as well and reverse engineer past successful marketing strategies for similar products? Here is my tentative list of those products:
Benson Gyrocopter, BD-5, EZ's, Quickie, Quicksilver, KR's, Kitfox, Mini 500, Jet Ski, Ski Doo, Harley, Ninja, Hobi cat, Rhino, Camero, Okley, Cannondale, Airbike, and; well you get the idea.
What if anything is the common element that we need to copy?
Not as an ultralight, and probably not even as an LSA, but I see no reason it can't fly, and with very good performance for some missions. Looks kind of like a cross between the Opal and the Rans S-11.
The S-11 idea could be messaged into a viable LSA?
Keep looking, it won't fly
Given who designed it, *cough* Orion *cough*, I wouldn't be so sure about that. :gig:
(Plus this was an early version, before really detailed design and analysis had been done. Don't know where he is with it now.)
Yes, I know who designed it, but it won't fly, he knows that too.
Keep looking, this is a test.
Ok, I give up! What have we missed?
OK, I'll give it away. It doesn't have a vertical tail drawn in yet.
It would either need a tail on booms, or if the tail was on the existing structure, it would be the size of Utah. Which is why he didn't draw it in, because he couldn't figure out how to make it look good (if I recall correctly).
Edit: also that kind of combination of delta plus straight wing isn't so efficient.
One of the difficulties of transforming an artistic concept to something that is to be functional is that you really don't know what was behind much of the reasoning that jerry Blumethal used in coming up with the configuration. In doing the work I did to get it to tis point I started with the sketch but then had to come up with a mechanism to make the balance and control authority work in such a way that static and dynamic stability were satisfied.
At this point I did not concentrate too much on the latter but did spend quite a bit of time in shaping the fore-body so as to satisfy the former. In other words, the design does work as it sits, it has a usable CG range to account for a variety of occupants and it has proper handling characteristics.
Regarding lateral control and stability, "Starman" is partially right in that in this picture the design does not have yaw control, although it does have yaw stability. Given the CG range location (about at the seat back of the aft passenger), there is more effective projected area aft of the balance point than there is forward, albeit, not by much. But given the stabilizing influence of the pusher prop, the configuration as it sits should be laterally stable.
For lateral control though the only option is tip verticals, which is what I started to sketch but never modeled. They do have sufficient authority and are located far enough away from the fuselage so as to minimize the typical tunnel effect (they're also canted outboard a bit). But contrary to "Starman's" statement, they do not need to be huge for effective control - my main issue with them was not so much size as it was structural configuration and control run.
As far as application of this configuration to the subject at hand, I think it could be feasible although it would be a rather hot little bird and not applicable to either the ultralight or LSA categories. furthermore, I think that by trying to make it so would dramatically change the configurational attractiveness. But then I do not feel that either of those categories will be key to revitalizing the industry.
Then we are doomed:hammer:
The old guard has neither the interest or the ability to adapt.
Yes...eventually the sun will become a red giant and engulf the entire inner solar system...but before that the seas will boil off......
none of us are getting out of this thing alive...
so what else is new?:gig:
I like the razor....wish I was an independently wealthy old eccentric...
We'd build one just for fun.
Okay, I'm heading out the door for a camping trip, so I'll try to keep this short - I have several long "draft" replies ready to put on this thread, but they'll have to wait till I get back.
I love the look of this design - even if it won't work for the ultralight we've been talking about.
BUT - in regard to lateral stability and vertical surfaces (rudder).
Please explain to me why you can't put the verticals on the other side?
Meaning the bottom...
If you had fixed, trailing link gear, it seems like you could kill two birds with one stone. Fair in the gear with an airfoil shape, transitioning to mini-rudders at the back of each leg.
This seems like it would see unperturbed airflow at almost any AOA except a crazy dive.
Is there a reason this kind of solution isn't considered?
I can't wait to hear the reason when I get back!
BTW, there is already a thread for this design - so unless we're going to blackmail Orion into letting us use it, it would be best to keep the threads separate :ermm:
Actually you can put the vertical on the bottom and yes, you could incorporate it into the gear, if you could make it pretty that is. The design I had in mind put the vertical at the tip and extended it below as well.
Okay, I lied... just picked up my youngest daughter from a Navajo mission trip, but waiting for my son arriving late from summer camp...
So I have a few minutes to spare.
If the verticals can be mounted on the bottom, then by all means DO SO !
I assume this craft is not going to be long legged, so no one will even notice them (if even see them) while the plane is on the ground.
On take off and landing, they're going to be less intrusive (aesthetically) than wing tips - which are atrocious looking!
Unless it's retractable, the gear needs to be faired anyway; with the complexity of retraction and the great stroke of trailing link gear, there's no reason to leave naked legs out there.
And to top it all off, while flying - it will look much better for photo opps, and you won't have ANY extran areas of blocked visibility (important for dog fighting).
THIS IS A "NO-BRAINER" TO ME !
Don't mess up the beautiful lines of this craft with horrendous winglets (please).
I never keep an eye on private messages, so sorry for the late response.
I'm in no way offended; I have thick skin - especially when everyone else is wrong:devious:
Seriously, I understand what you guys are saying, but for crying out loud, look at what you just said... "you should know how much its going to cost ahead of time."
How in the world are you going to do that if you don't have an idea of what you're going to build?
That's plane crazy! (like the pun?)
I'm sorry, but I don't see enough freedom in the 103UL to do anything else but to do the aircraft first, if only on paper.
What "potential for heartache and financial pain" is there in doing this?
This is a serious project to me, but I'm also doing it for fun. I'm asking others to join me in this. Yes, I could go out and try to do it on my own - but it wouldn't be anywhere as good as it could be, and I would enjoy the process much more if qualified people are involved.
Frankly, I almost did it on my own, because I know the downside is getting too many chefs in the kitchen... so my goal is to end up with only a few chefs, a couple of sou chefs, some servers and a maitre d', and of course me - the head dishwasher.
I've done enough informal research over the years to be comfortable moving forward with this.
I guarantee you, it will be much more expensive to do a formal marketing plan than build a prototype (assuming design and engineering labor is contributed/discounted... I can do most of the tooling and/or fabrication).
At the end of a marketing study, we'll probably end up without a clue as to what is needed, or a plane that is impossible to build... just lots of pain and heartache!
But if we build a prototype (and maybe multiple copies), at the vary least we'll have aircraft that we can have fun with - and hopefully even like the looks of ourselves.
In short, I have no probelm doing a marketing survey - if others are going to spearhead it.
Am I going to wait for it to be completed? Not likely...
If that means some of you don't want to get involved - so be it; each can draw a line in the sand where they will (as has already been done).
Jordan (UT) and I have the same opinion of who the largest market will be.
I'm convinced that the 'base' aircraft needs to cost less than $15k, and virtually nothing to fly (low fuel burn, inexpensive rebuild, etc).
I have opinions about a lot more parameters, but I don't want this to be a "hey, who out there wants to engineer Rienk's plane?" (sucka's). It may disintegrate to that, or my having to go it alone - but that means I'm no worse off than when I started this thread :ermm:
Okay, my son just showed up, so we're off to the cabins! (which is camping, according to my oldest daughter, which is ironic since she recently got back from a semester mission trip at a orphanage in Uganda).
Have a great weekend, all
I see that if the CG is at the leading edge of the straight wing that there will be a balance of vertical surface areas, but I thought that style of wing wouldn't work well, which is something I came across in my delta pusher design.
What I mean is that the combination of highly swept delta and straight wing would have the following problems. The straight wing lifts at fairly low angles of attack compared to the delta, if you have a high enough AOA to make the delta work then the straight part of the wing stall. So either the straight part is doing most of the lifting, which puts the lift pretty far back, or the delta is lifting, which puts the lift pretty far forward.
You could have the delta part at a much higher AOA than the straight part to have a more balanced lift distribution but it doesn't look like that in the drawing, and if the delta part was at a higher AOA it still has a much broader range of effective angles of attack than the straight part does, which makes it sort of inefficient, doesn't it? Correct me if I'm wrong
But what a cursory glance at the picture does not reveal is that the forward part of the body loft actually incorporates camber (design cl = .3) so it too lifts at low angles of attack, just as the wing section. In essence this design is a tandem wing configuration, with the wings sort of joined, if that makes sense.
The leading edge of the delta portion has a fairly generous radius so vortex lift is not anticipated to be a significant issue until well past about 25 deg. aoa.
And to make things more interesting, I have also sketched a version of this with the wing stub leading edge a bit further forward, thus making the design be more of a double delta configuration. I haven't really dug into that one though - just wanted to see if it could be made to work. Doesn't look too bad but I haven't put it into the CAD system yet so I don't have it to show.
Thanks for the clarification, I can see the camber in it now that you mention it.
That's good to know, that means my F-15 design will work after all :gig:
That kind of marketing I've already done - to my satisfaction. Granted, it's only based on info from California, but since this is 10% of the country, I figure it's good enough to go off of. (of course, I've also done a lot at Oshkosh and Lakeland - that's why we spent $15k each year to go to those shows)
I've done plenty of formal business plans over the years, and they include plenty of marketing mumbo jumbo (legit). That is required when you're trying to raise serious money. But after my first success down that road (after several duds), I learned quickly that it's a lot easier to use your own money (if you have it) than go through all the hoops necessary to use OPM.
For this project, I don't have the current cash flow to be able to personally fund the required engineering, R&D. If I did, I might go on my own - but then I realized that the goal (for me) is not a wildly successful ultralight, but a paradigm shift for the aviation industry, regarding getting young people getting involved. Thus, this project REQUIRES a large group of vested people involved.
Quite frankly, I'd even be okay with getting the project rolling and then letting others take over the whole thing. Sure, I wouldn't mind having my family name memorialized in aviation history, but I really don't have anything to prove here.
In addition, I'm a great "starter", but get bored once things get to production or maintenance stages - then I',m off to the next thing (of course, I usually have half a dozen things going on at the same time, so really I end up just shifting focus).
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