Scratch build powered glider

Started by PankajC, December 08, 2011, 05:59:59 PM

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PankajC

Well decided to build a bird that would act a a powered glider AND design the bird myself - even though I know very little of aerodynamics

To begin with, was wondering what would 'act' as a glider. So doing a bit of reading, from what I understood, was that the cubic loading needs to be low (i.e. less than 7 oz/cu ft). Further, the fulcrum for the control surfaces need to be far from the CG /NP.

With these two in directions, started of by listing the specs

Wing span = 50"
Chord = 7"
Length = 44"
Target AUW - not to exceed 700 gm

Now, in recent builds I have utilized a concept of using a thick block of EPP right behind the engine mount followed by a block of thermocol. These two provide excellent shock absorbing capabilities to the build. Since I am still learning to fly properly, this makes the plane a shade more resistant to crashes.



Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

After cutting the fuse and sticking the pcs together
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sanjayrai55


PankajC

Applying the cover to the bottom of the fuse and attaching tail.

(photo of not a very good quality)
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PankajC

Attaching the EPP block on the nose.
Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

reinforcing the surface for attaching wings

The 3mm x 10mm MDF strips were laser cut by VK of rcelectro
Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

after applying the top layer of the fuse, the chambers to access the servo and battery
Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

Now, for the belly and the landing gear.

I have made the UC detachable - here's how
The strut has been attached to a small piece of ply and then fit in the grove prepared in the fuse.
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PankajC

For Wing construction....

The basic Idea of wing is that this is a polyhedral with the flat portion being 30" and two raised portion of 10" each. The construction is as follows
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PankajC

not much clicked during wing building process.....

Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

Finally putting it together....

I am not yet decided on the type of prop to use. I have pictured both using a normal and folding prop
Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

OK, The finished product looks like this.


Now all that remains is to hand over to Divay next time I am on the field for the maiden.....

Spektrum DX6i | EP Pusher Trainer | EP CUB |

PankajC

Final ALL up weight = 665gm, hence the calculated wing loading is around 6.2oz/cu ft.

motor 50gm 1400Kv, battery 3S 1000mAH, 18amp ESC

---------- end of construction --------
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vineet

going good till now ,, waiting for the  further build {:)} .


this is going to be glow plane right ??

vineet


SunLikeStar

Very beautiful glider {:)} i think you should use a folding prop but the one you have mounted on the motor is not good I've tried it on the same motor, no thrust and lots of power drain.
Good job on the build log, do post video of maiden if possible :thumbsup:

PankajC

@SLS thanks for the encouragement. Any reference to the prop I should be using?
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SunLikeStar

i'll be getting this in my next hk order, but this on this also looks good and is similar to what i'm using right now.

abhay

Nice build..  :thumbsup:
Me too making a glider, got much help from your build. will post build log soon.. My material is indian balsa..Me too at your stage. i.e. still learning  ;D

@vineet sir, cant get "glow plane"
I can take off and fly well. Its landing which sucks :banghead::banghead:

PankajC

@abhay1290. Thanks and look forward to your build log
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vineet

Quote from: abhay1290 on December 09, 2011, 12:06:08 AM
Nice build..  :thumbsup:
Me too making a glider, got much help from your build. will post build log soon.. My material is indian balsa..Me too at your stage. i.e. still learning  ;D

@vineet sir, cant get "glow plane"

glow plane = which uses fuel burn , like all engines , nitro plane

VinayakR

Quote from: PankajC on December 08, 2011, 06:08:20 PM
Applying the cover to the bottom of the fuse and attaching tail.

Hello Pankaj Sir,

Nice build.   {:)}

I was wondering how do you manage to cover the bottom of fuse with bio foam sheet  :headscratch: or it's because of less thickness? I have used 5mm and 10 mm bio foam it's not so flexible  8-)

Thanks,
-Vinayak

PankajC

@VinayakR, thinner sheet is more flexible. That is why it was chosen. However, little bit of heat can form the 5mm into the desired shape as well.
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ashutoshn

Dihedral and ailerons generally don't go hand in hand. A di/poly hedral adds roll stability for a level flight, while ailerons makes the plane unstable by inducing a roll. So in effect both of these wing functionalities interfere with each other.

Ailerons are more effective on flat wing or a very minimal 1/2" or 1/4" dihedral wing.

PankajC

couple of flights done (not by me :-), left it to experts Divay and Manish )yesterday on a reasonably windy day.

First the nose was way.... too heavy. so removed the extra weight added on the nose and pushed the battery a bit back and things stabilized.

Noticed another thing, on 50% throttle, its stable, but on full throttle, the bird starts climbing almost vertically ( with no elevator input). Maybe the thrust needs to point downwards ....
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