1/3 KA7 Roehnadler build

[Danger Dan]

I have started to build the 5.3 meter KA7 I bought from Daniel Plouffe last summer.
The model was originaly bought from Etienne at Icare-rc.com http://www.icare-rc.com/ka7.htm

The Kit could be considerd as an "almost ready to cover" model since the wings and stab are prebuild but there is still some work to do... of course !
The model comes with no instructions except a single page notice written in german.... So you need to have some building experience to complete the model, but I guess very few R/C enthousiast will start with a 1/3 scale sailplane project .

Still the ready build parts are very well done and will need little work, if any. See by yourself with the pictures.

Pre installed top and bottom scale airbrakes.

I had to build the rudder almost from scrach since the provided parts were scarce and I had no plans.

I love the very spectacular forward swept wing planform on this aircraft !

Quite a big model too !

[lenb]

Hi Dan


Glad to see you aboard. I saw the post about the other planes you are giving makeovers.
Looking forward to seeing the progress!

LEN

[Danger Dan]

Looking forward to fly with you buddy !

Dan

[Stevenson]

Precise work dude.

[Malain]

Hey Salut DangerDan!!!

Nice to see you here; beautiful glider you're building there! Hope to see you (and the plane ) this summer at our annual Trois-Rivieres aerotowing event!

Marc

[Danger Dan]

You can count on me, mon ami Marc !

[Stevenson]

wow. Mammoth plane build.

[Danger Dan]

Managed to calculate and find the CG margin today with that nice little tool you guys probably know of : http://adamone.rchomepage.com/cg_calc.htm
There are a couple of those "calculators" on the net but I find this on quite easy to work with. There is also some short explanations on the page that I found very useful.

This is what I got with my Ka7 mesurements:

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[Danger Dan]

Notice that I had to enter a negative value for the " wing sweep distance" since the forward sweep planform on the Ka7. I've entered 3 different values (5,10 and 15%) in the static margin field to get an approximative range of balance points. The figures I get are quite satisfactory since they all put the CG more or less on the passenger's seat ahead of the spar. I feel reassured since I had no experience on balancing a forward swept wing aircraft.... Here's a shot of the markings I've drawn on the wing root based on the numbers I got from the "calculator"
The 15% static margin entered in the first spredsheet gives me "from wing root LE to CG" = 2.16 inches.
10% = 2.94 inches
5% = 3.71

I will likely start with the 10% static margin figure and place my CG at + or - 3 inches from leading edge and probably move it slowly aft after some flights.

Marks on my wing root.... Quite unusual to put CG markings in FRONT of the spar !

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[lenb]

Dan,
Reminds me of this famous video. lol

Watch and enjoy

[Danger Dan]

Oh yes !!!! You really saved this fellow's day... and a very nice model from an almost certain crash ! Scary that was
Great video and VERY instructive animation on CG placement at the beginning too. Really cool. Tks !

[Danger Dan]

I need advices for 1/3 scale instruments ? I found a couple of adresses on the net but what would you guys recommend ? Any U.S. or Canadian distributor ? Is there different products ? Quality ? Thanks for your help.

[lenb]

Those from Iflytailies are good products

[Danger Dan]

Ok thank you Len.

[Danger Dan]

Took me all afternoon to to cut and fit the canopy parts !!! Here loosely put together. Most complicated canopy I've ever done, and still quite a lot to do.
But it should be nice at the end !

[Danger Dan]

Hi guys. ! Got a pair of 1/3 scale sliding windows from iflytailies today. Now I need a little help to install them ! Built a lot of models in the past but never installed any of these. Thread ? Pictures ?
Thanks !