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gicummo

Member
Joined
Nov 19, 2009
Messages
20
Location
montevideo / uruguay
Hello,

I am new in the forum (just a month); I was reading a lot of post because I am thinking in build an airplane, but I do not decide which one by the moment.
I pretend a simple and chep ultralight, the most simple of all, but is difficult to decide. I jump from the SkyPup to some of Beaujon models, there are a lot of models I can not chose because are based on aluminium 6061 T6, and it do not exist in my country, so just wood or composite ones.

My question is simple, If I choose a model x, can I build a scaled model to validate it? If yes, which is the minimun scale to use?, what about weight, dimensions, etc?... I think this is a problem of "model theory", may be it could be to difficult to acomplish, may be not.

By the moment that's all.

thank you, and best regards.
 

PTAirco

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Sep 20, 2003
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Corona CA
There probably is a material equivalent to 6061 aluminium in your country, but it may be called something very different. In Europe for example, HE30 is about the same. I would try calling some metal suppliers and see what they say - 6061 is used pretty universally worldwide.

What are your ultralight rules in Uruguay like? Do you have some kind of homebuilt aircraft/ultralight association?
 

orion

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You may want to search the forum for your answer - we have discussed the testing of models before. But the short answer is no, a small model will not do a good job of verifying your airplane unless you have a well instrumented model and the budget of a small department at NASA. The issues of scale (Reynold's Number), wing load, power loading and mass distribution make it very difficult to arrive at any really useful correlation.

But on the other hand, it is not useless either since the flight of the model may get you excited about building the full sized thing. And if properly balanced, along with a correlating mass distribution, the model may be able to provide you with qualitative information such as how it stalls, spins, etc.
 

gicummo

Member
Joined
Nov 19, 2009
Messages
20
Location
montevideo / uruguay
PTAirco,

About Al. the only one I can found here is 6063 in all the Tx variants, they do not work with 6061 because it's very difficult to extrude (for them), very rigid, and there is't market for this kind of Al.
You ask me about the ultralight rules here... wait a moment..here they are (what I found)

103.1 Applicability.
This Regulation establishes rules governing the operation of ultralight vehicles in the
Oriental Republic of Uruguay.
An ultra-light vehicle is one that:
a. It is used or intended to be used for air sports or recreational activities only, unless that the aviation authority authorized in each case, other activities.
b. Reserved.
c. The maximum capacity is two occupants.
d may be motorized or not, having the following characteristics:
(1) If it is not motorized shall have a maximum empty weight exceeding 70 kg. (except parachute).
(2) If motor shall have a maximum empty weight exceeding 260 kgs. excluding the weight of floats and elements for use in emergencies (eg vehicle parachute).
(3) Possessing a fuel capacity not exceeding 20 lts.
(4) possess a maximum calibrated airspeed in level flight with maximum power of 60 knots (102 km. / H.).
(5) Possessing a speed calibrated without power loss in landing configuration, exceeding 30 knots (50km. / h).
etc...

Talking about an association, yes, here are some, but none of homebuilt...
The best choice is something like Beaujon BEBE, but my doubt about it came from the net; I do not see anyone build/flown. There's another one but no so simple, the whing-ding; I do not know, let' see/study more.

thank you
 

Dana

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6063 is similar to 6061 but not as strong... about 21% weaker in the -T6 temper. It is sometimes used in ultralight aircraft, mainly in sizes where 6061 isn't available, but with allowance for the reduced strength.

The Whing DIng by all accounts is a very marginal aircraft, good for hops the length of the runway but not much more. Some have beefed it up and added larger engines but there are probably better choices out there. I don't know much about the Beaujon designs; they're another one from the early days of ultralights and not too popular now, but there is, I think, a Yahoo group dedicated to them.

-Dana

In general, liberalism consists of A & B getting together to see what they can make C do for poor old D.
 

gicummo

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Joined
Nov 19, 2009
Messages
20
Location
montevideo / uruguay
I thoght replace 6061 for 6063... but...I do not have a piece of 6061 to compare with one of 6063.. so I am not going to play with this. I do not know enough to do this....by the moment ;0)
The WD-II just for loops you said?.. look



This photos come from here

A thing I tought was build a Texas Parasol, but with wood like the Pietenpol; the fuselage is similar, the wing...May be I can use 6063, or a wing like the one of the skupup (in the style of construction). why not?.

mario
 

lr27

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Nov 3, 2007
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I think, of the designs and possibilities mentioned, the Skypup is the most promising. Many of them have been built and flown with success. I've looked over the plans a little and they appear to be for real. No need to do a test model, since lots have been flown. However, if you're big and heavy (as I am) it may not be a viable option. I seem to recall that gross weight is a little limited.

Another possibility, although I don't remember if it was steel tubing or wood, is the Pietenpol Sky Scout. Plans are available. Not sure if it's quite light enough and it's probably more complicated than it needs to be. Not sure about the stall speed on this one, though that wouldn't be hard to calculate approximately. The books are fairly interesting, though they're outdated, of course. There are several other candidates in there, though I think modern designs may be a little simpler.

Quite a few Himax ultralights have been build. It and its relatives (MiniMax etc.) may be worth consideration. The Himax itself is built from wood, I recall.

I think people still build the HM14 Flying Flea as well. Just make sure you don't use the ORIGINAL plans from the mid 1930's!

If you can weld or learn to weld, and steel tubing is available to you, there are a bunch of designs out there. I don't know much about them except that there's a metal fuselage version of the Pietenpol.

If you want to save time and money, it's probably best to build an existing design that has been built in some numbers already.

Another route, if you just want to get in the air, might be to import either a "heavy" or two seat ultralight that was not registered in the USA as a light sport airplane by the deadline. I'll bet there are quite a few grounded ones that would still meet your national regulations. Of course I don't know how much trouble importing one would be!

The really absolute minimal aircraft with an engine would be one of those powered parachutes.

If you're going to build a model, then the bigger you build it the more applicable the results will be. But there will still be questions.

Keep in mind that I'm not a full scale pilot. Yet.
 

lr27

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Nov 3, 2007
Messages
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I think the Fisher designs are just kits.

As global sea level rises (ok, IF it rises), the low flying record will be broken in Death Valley or some place like it. But not by much!
 

gicummo

Member
Joined
Nov 19, 2009
Messages
20
Location
montevideo / uruguay
We are going out from the subject of the thred, but the engine... I do not know, it dependes on the airplane, no?... but I thought in 1/2 VW, or a citroen engine; there are lot of this engines here. But as I said, I do not know, any engine will be hardest part to achive and the expensivest of the proyect ( If I decide to start with some...)

Regards.
 

J.L. Frusha

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Feb 17, 2006
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270
Location
Luling, Texas
The plane in those photos is the Pamperito, of either Spain, or Brazil. It is based on the Whing Ding II, but has ailerons. The Whing Ding II uses wing-warping like the Wright Brothers, so long ago...

I found the image, while searching for the Pamperito... Looking for plans and manual, which have been available, but I have not found them, yet.
 

J.L. Frusha

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Feb 17, 2006
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Luling, Texas
Yeah, I found better on another Yahoo group. Members all over the world...
ul-x : UL-X Ultralivianos y Experimentales

Images are a tad larger, but some important info is left out. Ailerons are only on the lower wings, upper wings are 3 rib sections longer, no mention of bearing/mount of ailerons... Having a Hell of a time. I'd rather have a complete set of plans and a manual. Then I can translate one part at a time, as needed.

I am trying to contact the designer and several builders...
 

BigBen

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Aug 13, 2011
Messages
62
Location
Sebring,FL
Gicummo,
Did you ever get into building your ultralight?
I am seriously looking into relocating to Uruguay and would like to be able to correspond with you on building and flying light aircraft in Uruguay. Where are you presently living in the country?
 
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