Q-500 Racing Discuss AMA 428, AMA 424, and any other variants of Quickie 500 racing

New Italian Q500

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Old 10-10-2008, 07:20 AM
  #1  
B.P.R.
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Default New Italian Q500

The new guys (from Foligno Italy) are come into the pylonracing world from just a year and are already making great strides.............. This is their new model designed and built http://www.giustozzi.eu/?cat=6
and some video http://it.youtube.com/watch?v=KvyKnKfr3Sw http://it.youtube.com/watch?v=NlOXfWQ3rpg
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Old 10-10-2008, 07:24 AM
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Default RE: New Italian Q500

Very neat looking plane.
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Old 10-10-2008, 07:50 AM
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Default RE: New Italian Q500

Are those wingtips legal for us?
If so what is the advantage of them?

Nice looking plane
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Old 10-10-2008, 08:39 AM
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Default RE: New Italian Q500

Those type of Wingtips are legal for 424 and 428 as long as the wing meets all of the other wing rules.
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Old 10-10-2008, 08:51 AM
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Default RE: New Italian Q500

Basically it still needs to be 50"-52" projected with constant chord of 47.5".
Does that nifty looking projection do anything for speed/flight characteristics?
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Old 10-10-2008, 08:57 AM
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Default RE: New Italian Q500

From Wikipedia, I'm not sure if anyone has done objective testing on our racing models.

Wingtip devices are usually intended to improve the efficiency of fixed-wing aircraft.[1] There are several types of devices, and though they function in different manners, the intended effect is to reduce the aircraft's drag by altering the flow near the wingtips. Wingtip devices can also improve aircraft handling characteristics, and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing, with less added wingspan. An extension of span would lower lift-induced drag, but would increase parasitic drag, and would require boosting the strength and weight of the wing. At some point there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan.

The wingtip devices increase the lift generated at the wingtip, and reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio. This increases fuel efficiency in powered aircraft, and cross-country speed in gliders, in both cases increasing range.
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Old 10-10-2008, 09:13 AM
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Default RE: New Italian Q500

Yeah right...[sm=drowning.gif]

So it looks cool and does the same thing as any other wingtip we might choose to use.
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Old 10-10-2008, 09:17 AM
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Default RE: New Italian Q500

I like the shape of the fuse. It looks like it would hold KE pretty well.
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Old 10-10-2008, 09:44 AM
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Default RE: New Italian Q500

As neat as it looks, there are quite a few things I see that could be optimized for a faster airframe...
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Old 10-10-2008, 09:46 AM
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Default RE: New Italian Q500

That carbon covering gets ya every time
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Old 10-10-2008, 02:48 PM
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Default RE: New Italian Q500

I’m skeptical that the wingtips do much more than add to the “that looks cool” factor. Span-wise flow on the wing is the enemy, and tip plates do help limit the flow, but with the penalty of more surface area, and more intersections. Having the top and bottom surfaces of the wing meet at an acute angle does about as good with no junctions. Having the wing sweep forward about an inch or slightly more does a much better job. As far as the rest of the design, there are several things that are not working for the design.

First off, the surface area of the fuselage is much greater than desirable. There is no need for any part of the fuselage to be above the centerline of the wing’s airfoil. Doing so just adds more surface area, and adds more dirty junctions to create drag. While there are things you can do to help maintain laminar flow along the front half of the fuselage, once you get behind the wing, the air is very turbulent. So it is even more critical to reduce fuselage surface area behind the wing.

Secondly, on the side view, it appears that the nose of the fuselage either sweeps up, or is somewhat symmetrical. A better design has the airflow around the wing in mind, and configures the fuselage along that line to lower drag. While it does not make too much difference in the straight-a-way speeds, it seems to matter more in the turns.

No point in discussing the tail, what works there is pretty well known.
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Old 10-10-2008, 08:10 PM
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Default RE: New Italian Q500

It wins my vote for a cool looking airplane.[8D]
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Old 10-11-2008, 03:01 AM
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Default RE: New Italian Q500

Dear HighPlains
I'm the designer of Fulginium Q500 and I read with attention your indications for improve this model.

In aeronautic "all that is beauty is good too" and I basically want to change look of this horrible Q500 rectangular wing.
In accord with you I believe that "aerodinamic factor" is secondary than "looks cool factor", but it function too.

What do u think I must change for better performances?

In attachment an image of other wingtips...javascript:void(AddText('',''))




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Old 10-11-2008, 08:11 AM
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Default RE: New Italian Q500

Here is a discussion of wingtip shape.

http://www.rcuniverse.com/forum/m_67..._1/key_/tm.htm



Slightly radical wing platform, with photo of tip shape from above. Also shows a minimum area fuselage design with top and side view.

http://www.rcuniverse.com/forum/m_20...y_legal/tm.htm
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Old 10-11-2008, 08:08 PM
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Default RE: New Italian Q500

HP, I think your best contributions are behind you bro,
Those threads were some of the most informative I've read in a long time. I even remember reading the short nose one while it was active but I wasn't interested in Q500 at the time so most of it didn't register. Excellent info thanks for sharing.
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Old 10-12-2008, 10:06 PM
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Default RE: New Italian Q500

what would be the better, a V- Tail or this original tail design type ?
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Old 10-13-2008, 01:58 PM
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Default RE: New Italian Q500

I would think a V-tail with the leading/trailing edges even with the top of the fuse side corners so there are no 90 degree angles would be ideal to reduce drag which is the whole idea for going faster with the available power being roughly equal. While the original design may look cool, it as a lot of long 90 degree angles amoung other hings. IMHO... a cool looking airplane is the one out front with the 1st place or fast time trophy!


Dan
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Old 10-13-2008, 02:28 PM
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Default RE: New Italian Q500

All the faster planes in the world are equipped with a V-Tail.
See the Gallery ;-)
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Old 10-13-2008, 02:37 PM
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Default RE: New Italian Q500

Another kind of "V" Tail... [X(]
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Old 10-13-2008, 06:21 PM
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Default RE: New Italian Q500

Great photoshop work. Do you have pictures of me on the grassy knoll?
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Old 10-14-2008, 01:07 AM
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Default RE: New Italian Q500

If u give to me some pics I can "create" a new image in Photoshop ;-)
I'm working for improve Fulginium Q500.
Why short nose is faster? Because tail must be necessarily lighter or because is more easy turn around the poles?
Cg.

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Old 10-14-2008, 01:44 AM
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Default RE: New Italian Q500

Nose length is set by balance requirements. Having a smaller surface area in the fuselage is a method of lowering its drag. More important, of course, is the shape. You want the air to stay laminar for as long as possible. You can do this with the shape (having the fuselage width increase as you move further back), or as in the case of a muffler the heat does the same thing to a constant section.

But eventually, you have to contract the fuselage. It's best done behind the wing, to avoid airflow separation at the wing root/fuselage junction. At that point, the air is most decidedly turbulent, so the method of reducing drag is to minimize the surface area. However, this contraction can not be too fast, or drag goes up again. You can pinch the tail boom of the fuselage in and achieve a pressure recovery area, which actually extracts some of the energy from the turbulent flow.

Listen carefully to airplanes in flight, the more noise the airframe makes, the more drag they are producing. Especially in the turns.
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Old 10-14-2008, 02:47 AM
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Default RE: New Italian Q500

At the limit I can delete the entire fuselage, and obtain a model with only one arrow wing and two winglets like an "Horten"?
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Old 10-14-2008, 08:07 AM
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Default RE: New Italian Q500

Our rules require a tail (conventional design - which means the engine on the front, wing in the middle, and tail at the back). Another rule states that the minimum length of the model from the front of the prop to the back of the moveable portion of the tail must be at least 1/2 of the span. Even though a design can be made this short, the penalty is that the model is more difficult to control in pitch. Especially at take-off.

The first extremely short quickie I flew (much shorter that the current rules allow) would take off without me knowing which way it would go. It would sometimes go up and hard to the left, other times to the right. But it was very fast, so it could easily make up the distance lost on launch. After a half dozen flights, we decided that the reason was that it was taking off with the wing stalled due to the high angle of attack caused by the combination of the regular sized landing gear with the very short length. When the tail was lifted up a couple inches, then takeoffs were more normal. It still tended to pitch up, but was controllable.

But if you are developing a product to sell, then you need a much more benign flying model. So I would not design a short model, since many would have problems due to lower flying skills. But if you like to experiment, then try one.

Secondly, swept-back wings do not work well at the slow speeds that quickies fly at. I've seen several tried, and they wallow through the turns like a drunk pig. I have flown a couple planes with the wing swept forward (wingtips 1" or 2.5 cm forward of the wing root) and liked the effect. A few others have tried it, but not noticed any improvement. But perhaps their fuselage designs were too draggy and masked the change. I expect my next design for my personal use, will be swept forward.

HP, I think your best contributions are behind you bro
Vicman,

Perhaps so. But I think that there are still a couple of things to try. My last experiment was with the engine mounted to give 2 degrees of down thrust. Very interesting results.
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Old 10-14-2008, 11:38 AM
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Default RE: New Italian Q500

Very precious contribution.
Thanks.
Where I can download American Q500 rules?
Cg


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