my first scratchbuild

Started by harsha, March 28, 2011, 12:58:24 AM

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harsha

hi this is harsha,i successfully builded my first plane with coro 3mm,followed plans from this site
http://kcrcw.wordpress.com/2010/12/23/48/
but it didn't fly well.i have to change the wing as i constructed it wrongly(flutes doesn't run from trailing to leading edge)..

i used a2208\12t 1500kv motor
1047 prop
2s 1000 mah lipo
30amp esc
9g servos

here are some pics,the all up weight is 15 grams

plz suggest me where and what should i correct to make it fly better????

anwar

Good effort !

Can you elaborate on "it didn't fly well" ?  Without details, others may not be able to comment :(
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SunLikeStar

Quote from: harsha on March 28, 2011, 12:58:24 AM
plz suggest me where and what should i correct to make it fly better????
The plan you pointed to has a 5 degree dihedral but your plane seems to have none. The plane in your pics will be difficult to fly even for seasoned pilots as it neither has dihedral nor ailerons.

ujjwaana

1. Though you have not correctly called out the AUW (15g - kidding!!), the plane would be underpowered with 2822 motor if the AUQ is greater than 700g(and huge drag from the wing)

2. You Fin area is a bit small in proportion to the wing area. Make it taller as well You would no need that massive Rudder considering the distance of the Rudder from CG (moment of Yaw).

3. your battery mounting seem flimsy. please use a zip-tie with some hard plastic reinforcement on the wing where the batter would sit.

4. The boom, though looking tough, may not withstand a rough landing. Reinforce with some CF rod.
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PankajC

the rudder looks huge in comparison to the elevator. further as mentioned by sunlikestar, a plane without a dihedral would be difficult to fly - unless you have ailerons.

In anycase, do post as to what is meant by "didn't fly well"

Pankaj
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harsha

sorry guys there is a mistake in the post,the AUW is 615gms...its a mistake due to faulty keyboard  :P
ya it just flew a meter and when i tried to give the elevator it totally went in vertical direction the it flapped back due to heavy wind...
and thanks for the suggestions guys...i will make a new wing......will use a zip tie for the battery mount

harsha

#7
Quote from: ujjwaana on March 28, 2011, 01:27:23 PM
1. Though you have not correctly called out the AUW (15g - kidding!!)
...
...
4. The boom, though looking tough, may not withstand a rough landing. Reinforce with some CF rod.

thanks for the suggestions bro...the auw is 615gms,changing the motor will increase my budget so i want to use the same setup to make a beginner plane(of any weight,any model),so can i use this setup or i have to make any changes in the power setup?.....plz suggest guys

PankajC

whenever flying a new model and for newbies, it is advisable to have the controls on dual rate (if your radio permits) else have very little throws. so you might want to setup D/R or expo on your elev and rudder and try again
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rohitgupta322

If it went up vertically and flipped back, then the indications are that your plane is severly tail heavy. Try to move the battery forward and/or add weight to the nose as required.
The CG is located at 1/3 of the chord length from the leading edge. Divide the wing into 3 parts and then lift the plane at the first point from the the leading edge, the plane should tilt slightly forwards if it is perfectly balanced, if it doesn't do so then modify it as told above, and always do a non powered glide test before doing a powered flight.
Be Inquisitive

harsha

Quote from: PankajC on March 28, 2011, 11:10:41 PM
whenever flying a new model and for newbies, it is advisable to have the controls on dual rate (if your radio permits) else have very little throws. so you might want to setup D/R or expo on your elev and rudder and try again
dual rate???? how can i set that????

rohitgupta322

Be Inquisitive

harsha


harsha

thanx for the suggestions,what about the power system??? can this power system will be able to lift a plane of auw more than 600gms???
i tried by changing the prop,i used 8040prop but it moved heavily  :banghead: the suggested prop for this motor is 8040 and its given the auw can be till 488gms in the website where i bought this motor......i used 1047 prop it gave me very good thrust,when i holded the plane in my hand and gave full throttle it tried to move in the forward direction but when i tried with 8040 prop it moved very heavily,plz suggest me the AUW,the right prop and any other tips and suggestions are greatly appreciated.......... :)