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Aug 17, 2019, 07:52 AM
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Mini-Review

my first homemade plane flying


I am very proud to present to you my first airplane imagined and built by me
it is a small "parflyer" hand launch built with almost all parts in Depron. I used mainly depron 6 mm except for empenages which are depron 9 mm.i cover the wing and fuselage with a 25g /m˛ fiberglass veil with floor varnish , it is light, it stiffens a little the structure and it absorbs quite a bit shock of the transport and landing in the high grass
I wanted a construction rather simple and fast to build so it is quite cubic but with a slightly more finished appearance than an EPP foambord plane
I designed it on a 3D drawing software and I printed "the pattern" on sheets of A4 paper that I carried on the foamboards of depron and cut with a cutter. I then assembled everything and stick to the polyurethane glue and a little bit of hot glue.
I give a slight positive 2.5 ° dihedral wings that are mounted in a high position or a little median

It is 110 cm wingspan for 88 cm long, a wing area of ​​21.6 dm˛ for a empty weight of 727 g and 875 g with a Lipo 3s-1800mAh which gives a good 41g / dm˛ of wong loading
I mounted a Brushless OS engine OMA3805-1200 which drives a 9x6 MasterAirscrews propeller that provides a power of 253 W

It looks a bit like a cross between an American P47 for the massive look, and a Japanese Zero for the shape of the canopy and the engine cowl painted in black

the first flight was "epic" because the proppeler and his mount go away 100 m after takeoff. , it was vibrated a lot same as an IC engine followed by a long silence and a total loss of the power. the contact with the ground was very virile. After several rebounds I saw big pieces come off. When i arrived at the crash zone I was reassured because the big pieces that were detached was in fact the canopy which is removable to access the battery and the engine cowl which is also removable. the only damage on the plane was just the tip of a wing a little bit distorted and some cracks on the wings and fuselage

since I made fifteen flights, it is easy to fly ,i can fly slowly and also capable of very good accelerations, a good rate of climb, it is very responsive on the roll axis . The wings are hold with elastics but it's very strong . i do several dive same a dive bomber without problems
the only 2 points that need improvement and the fact that I find the rudder control not enought efficient and I have a problem in the looping, it always turns 90 ° left at the top of the loop

Tell me what you think about
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Aug 17, 2019, 08:13 AM
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rajazo's Avatar
Looks nice and fun . Congrats for your first successful design!
About the rudder, it looks a little small, specially the moving part, but Check the stiffness of the fin , if it flex too much, rudder control is ineffective and some weird things could happen.
Actually I use two layer of 5mm foam on the fin of my planes, and react really predictable, resist a lot of abuse and the drag penalty is imperceptible.
Aug 17, 2019, 08:17 AM
Build more, websurf less
FlyingW's Avatar
Very pleasing shoulder-wing design. Nice job.

Might be running out of airspeed at the top of the loop.

Looks like it fits conveniently in your car.

Have fun with her and fly safely.

Paul
New Jersey USA
Aug 17, 2019, 08:44 AM
treefinder
springer's Avatar
Good looking and well executed build!
On the loop roll off, I agree with Paul, that you might be loosing too much airspeed and it is tip stalling. I find I frequently, while cruising at maybe half throttle, will pull up into a loop and just get to the top, run out of speed and it will fall off to one side. When I remember, I add power on the up side and can then get over the top in good form. You might also check for subtle fuse curvature or wing warps (washout different each side) that can be compensated for in level upright flight, but cause problems in inverted or near stall conditions. A bit of detective work, part of the fun of scratchbuilding!
Aug 17, 2019, 08:47 AM
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Thread OP
Quote:
Originally Posted by rajazo
Looks nice and fun . Congrats for your first successful design!
About the rudder, it looks a little small, specially the moving part, but Check the stiffness of the fin , if it flex too much, rudder control is ineffective and some weird things could happen.
Actually I use two layer of 5mm foam on the fin of my planes, and react really predictable, resist a lot of abuse and the drag penalty is imperceptible.
thank you for the advice but it is not a big problem i can turn only with the rudder but it's slow . i'm not using too much the rudder when i'l flying so i'm not worried
Aug 17, 2019, 08:55 AM
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Thread OP
Quote:
Originally Posted by springer
Good looking and well executed build!
. You might also check for subtle fuse curvature or wing warps (washout different each side) that can be compensated for in level upright flight, but cause problems in inverted or near stall conditions. A bit of detective work, part of the fun of scratchbuilding!
for a while i thinking the problem was lhe left wing damaged during the crash of the maiden flight , but i checked , it the same washout on both wings . i checked again and i found the left horizontal stab not perfecty aligned !!! maybe it is the source of the problem
Aug 17, 2019, 09:26 AM
He who stalls....falls!
Neat !
Nice model for your first original design.
Have you given the model a name?

cheers
Aug 17, 2019, 10:01 AM
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Thread OP
Quote:
Originally Posted by H1958D
Neat !
Nice model for your first original design.
Have you given the model a name?

cheers
i give it the number P19 (for 2019!!) but not yet a name . i'm open to any suggestions
Aug 17, 2019, 12:41 PM
TonyS
Quote:
Originally Posted by Remtherebel
i give it the number P19 (for 2019!!) but not yet a name . i'm open to any suggestions
Perhaps "Alouette"
Last edited by tonystro; Aug 17, 2019 at 12:42 PM. Reason: To correct translation
Aug 17, 2019, 02:28 PM
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Thread OP
Quote:
Originally Posted by tonystro
Perhaps "Alouette"
good idea but ... it is the name of a french helicopter
Aug 17, 2019, 02:29 PM
Registered User
I've had some badly asymetrical planes that could be looped fairly easily.
Your inability to loop is almost certainly because of stalling at the top of the loop.
I suggest entering the loop with more airspeed and power from the very beginning of the pull-up.
Aug 17, 2019, 03:47 PM
flyin' fool
goldguy's Avatar
Did you balance the P19 laterally?
Aug 17, 2019, 05:00 PM
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Quote:
Originally Posted by goldguy
Did you balance the P19 laterally?
no and i'm thinking now after a flight today , it is the problem . i put a mobius camera inside the canopy with the lens looking lateraly and it's much better , not yet perfect but much more better
Aug 18, 2019, 01:50 AM
Registered User
Quote:
Originally Posted by Remtherebel
no and i'm thinking now after a flight today , it is the problem . i put a mobius camera inside the canopy with the lens looking lateraly and it's much better , not yet perfect but much more better
So you are are able to loop now?
Extremely unlikely that some minor lateral imbalance that didn't affect level flight was the cause of loop impossibility
Have you changed any other variables? (like CG position via addition of camera and/or maneuver entry airspeed)
Aug 18, 2019, 03:12 AM
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Thread OP
Quote:
Originally Posted by nuteman
So you are are able to loop now?
Extremely unlikely that some minor lateral imbalance that didn't affect level flight was the cause of loop impossibility
Have you changed any other variables? (like CG position via addition of camera and/or maneuver entry airspeed)
the CG don't move a lot , maybe 1 or 2 mm because i don't feel difference with the others flight .


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