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Old Oct 25, 2012, 03:59 PM
speed is always addictive lol
Joined Mar 2009
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yello, and i saw Eisvogel was polishing the rib by hand at the thread, was it accurate enough?

why the central rib was sandwich? is there any difference between inner turner and outer turner motor with the same output power? and if the spinner important??

too many questions......hope you don't mind~
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Old Oct 25, 2012, 04:35 PM
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BCD;
as expected a lot of questions, lookes you have been really infected!

Just take the Turnleft as example, it is not really competitive in F5d but it can handle low F5d powers with a foamcored Balsasandwich without having a proper spar,so i think with the help of a little carbon it should be possible to get a scratchbuilt wing which is worth to be called F5d-style.

For you it may be an easier start-up to reduce wingspan a little,1200mm would reduce torsion and bending moment a lot, but also would reduce corner performance.

To control the torsion forces i think it will be necessary to use carbon weave .
Its pretty simple just cover the balsasheets inside with 80 or 93g/m carbon before you press it to the foam core.

As i built my 2/3 (the one at the Ford race car) i was really surprised how light and stiff the wing was after finish.


I think i will build an other one in the next 2 weeks, maybe the simplest way would be to have a skipe workshop,i just place my webcam ahead of my workbench and you can follow step by step,and ask questions.

enough for today, its late,let us continue tomorow
Regards
Yello
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Old Oct 26, 2012, 12:14 AM
speed is always addictive lol
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Quote:
Originally Posted by Mreyello View Post
BCD;
as expected a lot of questions, lookes you have been really infected!

Just take the Turnleft as example, it is not really competitive in F5d but it can handle low F5d powers with a foamcored Balsasandwich without having a proper spar,so i think with the help of a little carbon it should be possible to get a scratchbuilt wing which is worth to be called F5d-style.

For you it may be an easier start-up to reduce wingspan a little,1200mm would reduce torsion and bending moment a lot, but also would reduce corner performance.

To control the torsion forces i think it will be necessary to use carbon weave .
Its pretty simple just cover the balsasheets inside with 80 or 93g/m carbon before you press it to the foam core.

As i built my 2/3 (the one at the Ford race car) i was really surprised how light and stiff the wing was after finish.


I think i will build an other one in the next 2 weeks, maybe the simplest way would be to have a skipe workshop,i just place my webcam ahead of my workbench and you can follow step by step,and ask questions.

enough for today, its late,let us continue tomorow
Regards
Yello
i think a F5D style or likely will be enough for a rookie at a first step

regardin to the carbon reinforcement, which resin can be use? local guys use a type called "E51" for glassing or carboning, but no one tried to use it on a speed plane, is it ok?

and i checked the local market, the lightest carbon weave is 200g/m^2, would it be too heavy for a pylon racer?

good to hear you'll take a vid, and your car looks pretty good, so the bbs rim as well~
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Old Oct 26, 2012, 12:21 AM
speed is always addictive lol
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or, is that glass acceptable?

how's the diff between carbon and glass on the same weight?
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Old Oct 26, 2012, 11:14 AM
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Originally Posted by bigcatdairy View Post
and your car looks pretty good, so the bbs rim as well~
The BBS rim car is Eisvogels, the one i was talking about is this one:
http://www.rc-network.de/forum/showt...=1#post2782244

But you are right ,it also uses BBS!



I thought about your problem and i think you should reduce wingspan to arround 1200-1250mm.
No idea about the airfoil,i think the usual F5d airfoils are designed for moulded built,i dont know how accuracy may effct the performance or which airfoil would take the most inaccuracy.
As i remeber right some F5d limited racers have been built as balsacovered foamcore with WMH-7518 with good results, also the MH43 works fine at the Turnleft.
A collectinon of usual F5d airfoils including coordinates you find here:
http://www.aerodesign.de/profilelight/pl12_m.htm

Short interuption my wife is calling for dinner!

Yello
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Old Oct 26, 2012, 11:36 AM
speed is always addictive lol
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Originally Posted by Mreyello View Post
The BBS rim car is Eisvogels, the one i was talking about is this one:
http://www.rc-network.de/forum/showt...=1#post2782244

Short interuption my wife is calling for dinner!

Yello
yello, good evening!

haha i recognized the rims coz i would like to present myself a set as a gift to celerbrate my first million $ sales number in my career~ but not yet~

i had browsed the site, it looks pretty good for new designer, and i noticed the topic "Sandwichbauweise mit Holzbeplankung" and i think it will help me off my build, could you please kindly telle me the keys of this topic?
just the keys will be ok since i don't wanna spend so much of your time.

and i think it will alway make men feel good when his wife calls him to supper

guten Appetit
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Old Oct 26, 2012, 12:04 PM
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Thank you!
Lets continue..
For example,
The WMH 7518 with about 1250mm wingspan would be more or less the layout of the Sharky which i built(based at the Tokoloschi) 2004 right after the regulation change.
It would be easy to built with foam core as the leading and trailing edge is straight.
The Sharky showes a nice flying behavior and easy handling even with high wingloads.
Maybe corner performance is a little lower than my Flipper but it is pretty fast at the straights.
From the aerodynamical side i am pretty sure possible G-forces are higher than 30G.

Thomas G. still uses it at the german F5d-competition and he is able to score in the low sixties even with a quite oldfashioned 4S drive!
Here a picture:
http://www.koelleteam.de/projekte/sh...JDSCN2053.html

and some flying action:
Fast and Furious - F5D Pylonracing Wettbewerb Grevenbroich (9 min 29 sec)


The Sharky appears several times, first time at 1.20,just enjoy

Yello
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Old Oct 30, 2012, 10:39 AM
speed is always addictive lol
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Originally Posted by Mreyello View Post
Thank you!
Lets continue..
For example,
The WMH 7518 with about 1250mm wingspan would be more or less the layout of the Sharky which i built(based at the Tokoloschi) 2004 right after the regulation change.
It would be easy to built with foam core as the leading and trailing edge is straight.
The Sharky showes a nice flying behavior and easy handling even with high wingloads.
Maybe corner performance is a little lower than my Flipper but it is pretty fast at the straights.
From the aerodynamical side i am pretty sure possible G-forces are higher than 30G.

Thomas G. still uses it at the german F5d-competition and he is able to score in the low sixties even with a quite oldfashioned 4S drive!
Here a picture:
http://www.koelleteam.de/projekte/sh...JDSCN2053.html

and some flying action:
http://www.youtube.com/watch?v=HFcfazA9kHY

The Sharky appears several times, first time at 1.20,just enjoy

Yello
you mean WMH7518's straight line flying performance is better than it's corner performance? it would be good for my poor flying skill and 30G is so high enough for me now~

seems there is a bit difficult for me to find foam material here, so can i use hollow wing core instead?

thanks.
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Old Nov 03, 2012, 10:42 AM
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Hallo,
If you cant find the right foam for the core it might get really challenging.
But any way, even this one is pretty fast and torsion forces might be horrible:
http://www.rc-network.de/forum/showt...ght=IMPRESSIVO

If you have to built it hollow, i woult use 3mm ribs to get a good glue surface.
I would use 6mm Balsa for the spar but upright grain, covered with carbon rovings.
For the sharky i use 7 2400 tex rovings in the middle, dowstepped to 1 roving at the tips top and bottom of the balsaspar,so all over 14 rovings.

If you can get 60g/m2 fiberweave i would cover the inside of the balsaskin with one layer in 45 thread direction before gluing it to the skeleton.
Than sand the wing carefully to its final shape (you can sand down the balsa at the trailing edge right to the glas to get it pretty sharp.
Than cover the complet wing with on other layer of 60g glasfiber in 45 direction.
Be aware that you have to close the fiberskin complete to get the best torsionstiffness, so maybe its the best to overlay it a little at the leading edge.
Keep the ailerons small, i would center it at the middle of the halfwing with about 30 % of the half wingspan.
It is important to have the ailerons built as a closed box so maybe its the best to glass it seperately all arround!

If you manage to get this wing arround 250g it should be fine for arround 160-170mph.

About airfoils.
I assume after sanding there will be not much airfoil acurcy left , so i would take the thickest of the collection i sent you.

You will not get the same performance in staightline and cornerspeed than a moulded wing, but i would try to get the first succes to have a reliable one

As your shell would be allmost the same than what you get with the cheaper mouldys i am confitent that it may work!

Good Luck

Yello
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Old Nov 11, 2012, 01:42 AM
speed is always addictive lol
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hi yello!
just came back from a business trip, back to the work on my plane, i decided to try building a hollow wing with the help of concrete mould, actually concrete+fiber glass+wood+gypsum etc..... bcoz i just can find the foam soft like gum and 200g carbon or kevlar here.......and unknown performance glue.......

i drew the mould sections and will cut em with the help of laser cutter, concrete+fiber glass fiber will fill the space between wooden sections, gypsum on the mould surface then covere a thin layer of fiber glass, resin and pva on the top. hope it will work.

think i got you, will apply a 6mm balsa spar into the wing, sandwich skin( fiber glass layer on both sides of balsa and carbon strips reinforcement).

i'll post the pics when i'll begin, keep in touch, thanks.
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Old Nov 11, 2012, 11:49 AM
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yello, what's the type of the brown glue you used to joint moulds?
can i use resin instead?? thanks.
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Old Nov 11, 2012, 11:57 AM
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It is resin,mixed with microballons.

http://en.wikipedia.org/wiki/Glass_microsphere

Yello
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Old Nov 11, 2012, 02:29 PM
speed is always addictive lol
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got it, thanks bro!
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