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Old Jan 22, 2005, 08:05 PM
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Quote:
Originally Posted by AirX
Hi Mr. Boogie,

Just browsing the thread, working on a revised version of my S-54 and looking for ideas on former placement. Going Depron for faster prototyping. It can be made to look pretty good as has your F-35.

Cheers,

Eric B.
Hey AirX,

I was looking at your S-54 thread again and thought your former placement looked pretty good, but if there is anything I can offer as far as info or opinions just let me know.

Boogie
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Old Jan 22, 2005, 08:23 PM
EDF rules... :)
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Thanks Mr. B.

I was trying to get an idea of how many I could get away with or in this case without. Basically I want to pare the weight down from were it was and gain some size to it.

Keep an eye as I go about its design and chime in when you think I could do something better...

Eric B.
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Old Jan 22, 2005, 08:26 PM
EDF rules... :)
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Quote:
Originally Posted by RCParkflyer
The RC Homepages sites have a lot of features we would never use, but putting up a basic webpage is simple enough. Go and download a free copy of Netscape 7.2 I use the "Composer" to build my webpages, then I just create an index page on the RChomepage and copy and paste the Composer's HTML into the page. HECK of a lot easier than using that CAD stuff you do LOL
Hi Tom,

I will look into this..

Eric B.
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Old Jan 23, 2005, 08:14 AM
tow
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Cg

Hi!
Great construction! Think I`m in love..........
Have you determened your Center of Gravity?
I don`t see any markings on your plans.
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Old Jan 23, 2005, 10:43 AM
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Quote:
Originally Posted by tow
Hi!
Great construction! Think I`m in love..........
Have you determened your Center of Gravity?
I don`t see any markings on your plans.
Thanks Tow,

CG is called out in the actual size top view, it's between 55mm and 60mm from the wing LE/fuse intersection.
I would start at 55mm for first flights.

Mr. Boogie
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Old Jan 23, 2005, 01:49 PM
tow
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Quote:
Originally Posted by Mr. Boogie
Thanks Tow,

CG is called out in the actual size top view, it's between 55mm and 60mm from the wing LE/fuse intersection.
I would start at 55mm for first flights.

Mr. Boogie
Thanx!
I plan to make one slighthly owersize by a few percent maybe. Have a fan/motor combo on a shelf leftower from a ditched Alfa-Mig. Will see how it works out.

Regards ToW
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Old Jan 23, 2005, 07:35 PM
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Quote:
Originally Posted by tow
Thanx!
I plan to make one slighthly owersize by a few percent maybe. Have a fan/motor combo on a shelf leftower from a ditched Alfa-Mig. Will see how it works out.

Regards ToW
Tow,

I've heard good things about the Alfa-Mig power setup, sounds like a nice performance boost. I'd be interested to hear how you get on with the mods.

Mr. Boogie
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Old Jan 29, 2005, 11:54 PM
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Quote:
Originally Posted by AirX
Hi Larry,

The large rotor/motor holder is not hampering the fans ability to move the air, in fact it is near the best ammount of area for this diameter of fan. To explain this is difficult but I will try and I will hope that Klaus will correct me if I miss it. The smaller the diameter of the rotor the less eficient it will be in moving air becuase the airfoil will be moving very slowly thru the air and effciency will be quite low, for example the 20mm diameter of the motor is only 2.47" in circumference, the id of the shroud for the microfan is 6.18" and for reference the od circumference of the microfan motor holder/rotor is 3.33". The blade root of the microfan rotor is traveling at 139mph at 44,000rpm if the root went to the 20mm motor diameter it would be traveling at 103mph at 44,000rpm significant difference in speed and lift/thrust generated, the tip of course would travel at the same speed 259mph and creating the lions share of thrust, the difference in root speed is not enough to warrant loosing the cooling space the extra area inside the motor holder would give up to a smaller diameter motor holder. There is a specific amount of area that is near perfect for any sized diamter of fan and this I suspect has been accounted for in this fans design. Going to more blade length and the little area added does little to the thrust of the fan and in fact by going larger on the overall diameter would generate more thrust and greater efficiency but then it would not be the nice 50mm dimeter it is and fit the planes we want it to fit. To give another example if we were to take a gws 50 and put a 20mm motor in it it would get more powerful but only to a point because the blade area is so little it cant compress near as much as the microfan rotor and therefor will suffer when trying to get it to work in a scale ducting arrangement, wont draw well over a long distance nor will it pump out well on a long outlet. Lots of things to look at in fan design.

Eric B.
Thanks Eric for the info.I think I've push my wemotec to its limit with the setup that I've got and now it's time to get going and trying it out on my avro arrow.however I still am left with the challenge of designing a good heatsink for my motors.

Larry.
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Old Jan 30, 2005, 05:47 AM
tow
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I`m just started making templates.
Blew up the F-35 to 125% to fit the Alfa-fan getting the wingspan to 25 inches.
Looks interesting. LL keep you posted.
tow
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Old Jan 30, 2005, 09:36 PM
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Quote:
Originally Posted by tow
I`m just started making templates.
Blew up the F-35 to 125% to fit the Alfa-fan getting the wingspan to 25 inches.
Looks interesting. LL keep you posted.
tow
Sounds cool tow.

What thickness foam are you planning to use?

Boogie
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Old Jan 31, 2005, 08:39 AM
tow
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Quote:
Originally Posted by Mr. Boogie
Sounds cool tow.

What thickness foam are you planning to use?

Boogie
Still going for 3mm & 6mm depron - Eh, a little misprint I`m afraid. Scale is not 125% -should read 115%.
Front fuze is well under way. Laying up fuz formers tonight I think.
tow
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Old Jan 31, 2005, 07:13 PM
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Intake lip configuration

The following images show the sequence for intake lip installation.
Hope this helps the folks who've been asking.

B
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Old Jan 31, 2005, 07:28 PM
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Thrust cone template

Here's an efflux cone template.

Works for me so far.

Mr. B
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Old Jan 31, 2005, 10:16 PM
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I know you vacuum formed the lip, but how? Did you make a mold (if yes what material) and send it off somewhere or did you figure out how to do it with a "Seal a Meal"? What material, an old plastic wine bottle? All of the above questions apply to the canopy.
Your knowledge and help is appreciated.
Hurricane Larry
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Old Jan 31, 2005, 11:15 PM
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Quote:
Originally Posted by lslewis
I know you vacuum formed the lip, but how? Did you make a mold (if yes what material) and send it off somewhere or did you figure out how to do it with a "Seal a Meal"? What material, an old plastic wine bottle? All of the above questions apply to the canopy.
Your knowledge and help is appreciated.
Hurricane Larry
Larry,

The lip is vac formed using PETG sheets (the same stuff found in most consumer goods blister packs and toothbrush packages). The parts are very light and reasonably strong (if you don't crash them directly ).

The plugs are 'grown' directly from the CAD files using rapid prototyping technology. The inlets and canopy plugs were constructed in a similar manner. The CAD files are also used to derive flattened/foldable templates in the event that I am unable to make a plug for vacuum forming.

I have tried using empty water bottles and a heat gun with limited success. Clear heat shrink tubing over a plug also works to create canopy shapes.

Hope some of this answers your questions.

B
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