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New Pilot, First build, First problems.

#1
Hi, im from Mexico City im new to this forum, I´ve been reading FT articles and treads on this forum for a long time, finally I decided to start this hobby, I have to thank FT guys for making the hobby affordable and easy.

I pick up the plans for the scout in FT page and cut them in my local lasercut shop.

la foto 1.JPG

This is my first FT Build, very easy build and looks great.

la foto 3.JPG la foto 2.JPG

Everything works great, motor, servos, transmitter and reciver, the only problem is that i just couldn´t get it off the ground, so I look for all the things that are wrong with my plane.

first specs: My specs/Ft specs

Weight (w/o battery): 189g / 115g
Motor: 18-11 2000kv Micro Brushless Outrunner/ 2480 kv 250 size motor
Prop: GWS6030 / 5 x 3 prop minimum
ESC: Turnigy plush 10 amp / 6 amp minimum
Battery: 850mAH 2s Lazertoyz (42g) / 300 - 800 mAH 2s minimum
Servos: 2 x hxt500 (2) 5 gram servos/
Receiver: Turnigy 9X 2.4GHz 8Ch (18g)/

Links of my parts:
Motor: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=5358
Prop: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=27409
Esc: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=4204
Batt: http://www.lazertoyz.com/850-mah-25C-Slim-Line-74V-Lipo-_p_550.html
Servos: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=663
Receiver:http://www.hobbyking.com/hobbyking/store/__12339__Turnigy_9X_2_4GHz_8Ch_Receiver_V2_.html

My plane was clearly overweigth (189g without batt) and when i balance the plane was very tail heavy, i had to use 30g of lead and the battery (42g) at front of the plane to balance it. With the plane balanced the total weight was 259g.
The other problem is that it was underpowered, I look in the forum and this motor was recomended for this plane, but they clearly say the plane must be lightweight.
the only problem I cant fix is Mexico City altitude 2240meters (7349 ft) over sea level, I know air is thinner at bigger altitudes I dont know if this afects my plane.

How I plan to fix it:

-Buy a bigger motor im thinking the Emax 2480Kv ( http://www.banggood.com/EMAX-MT1804-2480KV-Brushless-Motor-For-Multirotor-p-933933.html)
-Maybe change prop but i think that depends on the motor
-Make it lighter, carefully make some holes on the tail and replace the foam with someting lighter, remove exess glue, change reciever I´ve read in the forums that HK6ch receiver works for turnigy9x (http://www.hobbyking.com/hobbyking/store/__12901__Hobby_King_2_4Ghz_Receiver_6Ch_V2.html).

I want to know if this changes could work?
Do i have to change the prop?
how does the altitude of my city affects?
What else do you recomend?
In a future,I would like to build a Mini Crusier or a Mini Guinea, I want to know if my current motor work?

That´s all for now, thanks for your time.
Andres.
 

AkimboGlueGuns

Biplane Guy
Mentor
#2
Your altitude may be causing part of the problem, but are you using normal Adam's Foam? The might minis are inherently heavy as they are when built with Adam's because of the limitations of the material, so any heavier foam will make them pretty drastically under powered. Your build looks great so if you want to save the airframe, I would recommend cutting lightening holes from the rear fuselage or tail surfaces, then covering them with packing tape or some similar material.
 
#4
That RX is too heavy for your plane. You can lighten it by removing the case but it still isn't as light as the 6ch rx. A micro 4ch would be ideal but I don't think they make one that binds to that module. You may have to move the servos forward. You can't really afford dead weight on this plane. Make sure your battery is as far forward as possible without hitting the prop. If you have to, you could slide your power pod out a 1cm and poke your skewers back in. Moving the motor forward a little should help offset the cg. Also try to get your esc in the power pod to keep the weight forward. I didn't use bullet connector for the esc/motor either trying to save weight.
That prop should be fine, with higher altitude the larger the prop needs to be. It will definitely work on the 1804 motor if you go that route.
 

rcspaceflight

creator of virtual planes
#5
The FT designs are meant for Adams Foam Board. You can't exactly substitute it with a different material without running into a lot of problems with the majority of the designs. Mostly because all other materials are heavier which not only makes the plane heavier, but it also makes the plane tail heavy which means you have to add nose weight. Which only makes it even heavier.

Your power plant should be perfectly fine for a small plane made out of the materials you've used. If you simply make the FT Scout wings longer/bigger then you would be lowering it's wing loading to a point where it will float in the air better and require less thrust. Or you could scrap the fuselage and replace it with a balsa stick (or carbon fiber stick).

Or just go with a bigger motor and make the FT Flyer.
 

Ace2317

Senior Member
#6
Yeah, it looks like you're just too heavy. You can probably beef up your motor and it'll fly, but remember that heavier planes don't fly as easily as lighter ones will.
 

joshuabardwell

Senior Member
Mentor
#8
To me it looks like he used a adams like foam, then covered with wbpu and craft paper.. only because you can see where the cuts are, it looks like white foam in there.
I guess I was thrown off by the fact that the un-cut sheets had the same covering, but you could craft-paper the sheet before cutting it, I guess.
 

AkimboGlueGuns

Biplane Guy
Mentor
#9
You are probably correct about the brown paper covering. If that is the case I would recommend not covering the mighty minis. They are tough enough as is and you really can't be adding weight to an indoor plane as heavy as those things are.
 
#10
Thanks for your advise!
but are you using normal Adam's Foam?...
I sure can't tell, but it looks like cardboard or some variant to me.
To me it looks like he used a adams like foam, then covered with wbpu and craft paper.. only because you can see where the cuts are, it looks like white foam in there.
Sorry i forgot to tell you wich foamboard I use, yes its foamboard but covered with Kraft paper (a bit more thicker), and for the wings I use a black foamboard with black foam, thease two foamboards are the lightest foamboards I can find in my city, here some pics:

la foto 1.1.JPG la foto 2.1.jpg

Your power plant should be perfectly fine for a small plane made out of the materials you've used. If you simply make the FT Scout wings longer/bigger then you would be lowering it's wing loading to a point where it will float in the air better and require less thrust. Or you could scrap the fuselage and replace it with a balsa stick.
I m going to try lighten the plane, bigger motor and maybe I make a bigger wing so i have bigger wingarea, or maybe...

bip.jpg

Biplane!...could be fun, but I think I stay simple for now.

This is the link of the store were I buy my foam: http://www.lumen.com.mx/catalog/detalle.php?IDSUB=473&TITULO=MAMPARA FOAM BOARD KRAFT&MARCA=3AC

Thanks for the help, now im going to fix my plane :)
 

AkimboGlueGuns

Biplane Guy
Mentor
#11
The foam you are using looks to be decent. Does it come covered with thinner paper? If it does I wouldn't bother with trying to cover with craft paper (unless it will be a float plane) because of all the extra weight it adds to an already competitively heavy airplane.
 
#12
The foam you are using looks to be decent. Does it come covered with thinner paper?
Yeah this foam is quite nice and is the lightest I can find, it give me great results when I cut it in a laser machine and it works great for building, but is like 30% hevier than Adams, I made my calculations and mine is .33 g/inch vs .19 g/inch Adams DT, Is not very much but for this plane I think it is.
I just oreder a bigger motor (2480kv), and im going to order a pack of 6040 props if i need more thrust, I also need to work on the fuselage so I can take some weight away.