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Old Mar 12, 2013, 06:46 PM
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Belgium, Walloon Region, Arrondissement of Mons
Joined Feb 2013
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Future project - The Sporty biplane

Hello all

My Pilotin is almost ended and I'm looking for a new project.

http://www.rcgroups.com/forums/showthread.php?t=1840545

I'm interest now for the RC conversion of the Sporty Biplane by J.S. Humphreys Aeromodeller 1950.

I think make 140 % bigger.
I 'm uncertain for dihedral stab profile and incidence for the RC : as the original or not?

Original incidences are +3 for upper and lower wings, 0 for the stabilo (stabilo is a Clark y type)

What do you think about it ?

Advance thank you.
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Last edited by Ptilou; Mar 12, 2013 at 07:35 PM.
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Old Mar 13, 2013, 04:06 AM
skumgummi dave
Gresham, OR.
Joined Mar 2004
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Lurking...
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Old Mar 13, 2013, 04:26 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Great choice Ptilou, it will make a great R/C model. You may want to reduce the top wing incidence a little and also the dihedral (I use the formula "1 inch (25 mm) per inch of semi span plus 1 inch" and always find this works well for a rudder controlled model. It would no doubt fly OK with the original incidences and dihedral, as a "climb and glide" radio model though.

I don't know how soon/quickly you are planning on building, but there is currently a "Britplan" build-off running which ends on 30th June 2013 - see http://www.rcgroups.com/forums/showthread.php?t=1796717 - and it would a an ideal entry for this if you are planning on building it within the next 3 months.

Are you thinking about I.C or electric power?
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Old Mar 13, 2013, 06:36 PM
Registered User
Belgium, Walloon Region, Arrondissement of Mons
Joined Feb 2013
90 Posts
Thank you Sundancer for response.

I don't understand well the dihedral formula
Quote:
"1 inch (25 mm) per inch of semi span plus 1 inch"
(My bad english...again)

For example if wingspan is 40 inch, which height put you in the right marginal edge If I puts the horizontal left wing on the table ?

I will use electric power for this time.

I shall be very honored to participate in the briplan, but 30 june it's not possible for me this year. In may, I need to move all my RC models workshop for a bigger. Great...but there is a lot of work, a wall to be built and there is no electricity ...no light.
But I shall be happy to participate for the next time.

I will first redraw the Sporty plans in CAD and I begin the construction when I have my new workshop.... I think august or September.
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Old Mar 13, 2013, 10:38 PM
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Gold Coast Australia.
Joined Jan 2005
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SPORTY is a fantastic old model.
I built one over 30 years ago and covered it in Modelspan tissue as per the Aeromodeller cover drawing colour.
Very good Free Flight flier built to the plan with a real Mills.75 in it.
At the moment the Mills is out of it in something else though.
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Old Mar 14, 2013, 12:27 AM
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Gold Coast Australia.
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Here you go my SPORTY built in 1981 I think, and not flown for about 10 years.

It's a dear old thing.........just like me......LOL.
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Old Mar 14, 2013, 04:10 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Quote:
Originally Posted by Ptilou View Post
Thank you Sundancer for response.

I don't understand well the dihedral formula (My bad english...again)

For example if wingspan is 40 inch, which height put you in the right marginal edge If I puts the horizontal left wing on the table ?

I will use electric power for this time.

I shall be very honored to participate in the briplan, but 30 june it's not possible for me this year. In may, I need to move all my RC models workshop for a bigger. Great...but there is a lot of work, a wall to be built and there is no electricity ...no light.
But I shall be happy to participate for the next time.

I will first redraw the Sporty plans in CAD and I begin the construction when I have my new workshop.... I think august or September.
Not to worry, there will be another build off of some sort starting 1st July - may even be one for biplanes, if so your Sporty would be ideal.

Sorry the dihedral is not clear. Using the formula for a 40 inch wing with one wing flat the total under the other tip would be 5.33 inches ( 1" + 1 x 1.66 ft = 1" + 1.66" = 2..66 inches per HALF wing) - I would make it 5 inches.

Good luck with the workshop move - I have just done the same thing and it is a lot of work. But I am very happy now I have settled in!
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Old Mar 14, 2013, 02:45 PM
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Belgium, Walloon Region, Arrondissement of Mons
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Quote:
Here you go my SPORTY built in 1981 I think, and not flown for about 10 years.
Your Sporty is very nice. I don't regret my choice for this model.
Mills is a nice vintage motor.
A luck to see it flying again ?

Quote:
Sorry the dihedral is not clear. Using the formula for a 40 inch wing with one wing flat the total under the other tip would be 5.33 inches ( 1" + 1 x 1.66 ft = 1" + 1.66" = 2..66 inches per HALF wing) - I would make it 5 inches.
Thank you Sundancer : I understood and I calculate it for my plane.
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Old Mar 14, 2013, 05:48 PM
Registered User
United States, NY, Ithaca
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Sky Buggy

It's a pretty plane and very similar to the Berkeley Sky Buggy, which was also FF. It was larger, with a 46 inch wing, I think.
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Old Mar 14, 2013, 06:49 PM
Registered User
Belgium, Walloon Region, Arrondissement of Mons
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Quote:
It's a pretty plane and very similar to the Berkeley Sky Buggy, which was also FF. It was larger, with a 46 inch wing, I think.
I don't know this Berkeley model. What is the year of the kit?
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Old Mar 14, 2013, 08:30 PM
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Gold Coast Australia.
Joined Jan 2005
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There is a photo of Sky Buggy in a 1949 Model Aircraft magazine, so it's at least that old.

Can remember Applehoney suggesting Sporty was a small copy of Sky Buggy.

Applehoney may know the original date of it and even have a plan????
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Old Mar 20, 2013, 10:07 AM
RFJ
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Northern Ireland
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Ptilou,

Bit of inspiration for you - from April 2013 BMFA News.

Ray
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Old Mar 20, 2013, 12:24 PM
Registered User
Belgium, Walloon Region, Arrondissement of Mons
Joined Feb 2013
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Wow thank you Ray.
I make a little search with google and I find the video.

Here it's very beautiful.


"Sporty 70 inch Wingspan Biplane model aircraft" (4 min 19 sec)


I think that I shall make bigger than 140%
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Old Mar 21, 2013, 05:18 PM
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Gold Coast Australia.
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That's really nice.
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