bogusbandit56 Show full post »
bogusbandit56
JTiger wrote:


How do you feel about chopping your wings down to see if that helps?


I`m already in the process. I have had to chop the wings down so that I can install KFm4 to keep it under 250 grams.
My other P.60 has KFm4`s and it seems to be the only difference apart from it weigh 350 grams without the battery.
I`m still of the opinion that the best way to tackle the issue of a sub 250 gram flyingwing is with the Armin type wing that has a true aerofoil so that a shear web of 6mm foam will support the top skin and when all is thoroughly glue together it will make a stiff wing without carbon reinforcing.
Wot, no Depron?
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quorneng
Agree entirely with the Armin type of construction but by using 6 mm foam there is something like twice as much material, and thus weight, than is strictly necessary.😉
For "big" lightweight planes the wing loading is low so you don't actually need a 'conventional' wing section to generate the lift. To achieve a reasonable flying speed at low(ish) power a thin streamlined (semi symmetrical?) section is all that is required but this of course is hard to do 'super light weight'!
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sietze
some thing like this can be build easily onder 250 grams. 
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FED50H


..and FPV to boot...so, subtract the camera and you are way under....
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bogusbandit56
Oh silly me I forgot, I have already done this challenge two years ago when I built a flying wing that didn`t require vertical stabilizers. This wing weighed 180 grams and flew out doors in a moderate breeze.
Wot, no Depron?
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Wildthing
Oh silly me, I have already done this challenge two years ago when I built a flying wing that didn`t require vertical stabilizers.


That's funny 😃 . Do you still have it?
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bogusbandit56
Wildthing wrote:


That's funny 😃 . Do you still have it?


Yes I do. It`s in the attic and there`s lot`s of planes up there I have forgot about.
I even have a P.40 that I started about 5 years ago.
Wot, no Depron?
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JTiger
Oh silly me I forgot, I have already done this challenge two years ago when I built a flying wing that didn`t require vertical stabilizers. This wing weighed 180 grams and flew out doors in a moderate breeze.


Lol, challenge complete!
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bogusbandit56
JTiger wrote:


Lol, challenge complete!

Yes, if my memory was a bit better I could have saved myself a lot of time🙂
That flying wing has a 32 inch wing span not a tiddly little indoors flyer and it flew in a light breeze, so like you say challenge completed🙂
Wot, no Depron?
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quorneng
My latest sub 250 g which started out as a 'toy' RTF - £7.99 ($10) at Lidl !
Unpack.jpg
As others many others have done I though I would try my hand at an RC powered conversion.
Stock with its substantial "bolt" nose weight it weighed 170 g
NoseBolt.jpg 
By keeping below 250 g it should be possible to get away without any structural reinforcing - well that's the plan!
Like many moulded foam planes it suffers from squared off trailing edges and in this case they are really thick about 1/3 the wing thickness!
The resulting drag is not too much of a problem for a powered plane but to glide properly and use as little power as possible the trailing edges will be extended using Depron to give a fine (less than 1 mm) edge.
Elevator1.jpg   
A test piece showing how the top tape hinged elevator would look.
As it will be flown 3ch bank and yank the 'rudder' is fixed.
EleRud1.jpg 
With the nose cut off the motor is supported by a glued on printed bulkhead.
MntrMnt1.jpg      
With the top and bottom parts of the cut off nose and a spinner added to the 5x3 prop for show!
The 'hollowed out' cockpit with the 950mA 2s, 10A ESC and the 4ch micro full range 35 mHz radio.
BattESC.jpg 
The 3.7g elevator servo is let into the side of the fuselage with external pull/pull lines to the elevator.
The aileron servos are flush with the underside of the wing.
AilServo.jpg 
The aileron horns are printed. The servo arms are set 45 degrees forward to give significant 'mechanical' differential movement.
Compete ready to go it weighs 224 g
Complete1.jpg 
Apart from any drag benefit the extensions have added nearly 18% to the wing area!
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DualDesertEagle
I just realized I never came back to this thread to mention my RCP Mig-29 and X-31, both built in original size and both lighter than 250 grams RTF. Since they're profile planes that's probably not much of an achievement but still, they're both fun to fly (tho the MiG could definitely use a more powerful motor and a 3S LiPo).

The MiG weighs 225 grams and the X-31 weighs 226 with and 217 without the removable landing gear, and had I not wanted to add said removable landing gear I could've saved some weight by ommitting the lego technic parts on the plane that the landing gear attaches to very easily. That said, 9 grams for a tricycle gear with simple knee joint suspension and some for the legos to attach it to should totally be worth it. Just need to find a place to take off from yet, but that might be just around the corner as I'm moving at the end of june.
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Lgel
Interesting project Bogusbandit56.

But I just met an RC pilot from France, where a law has been enforced ( min weight is 800g), and he was not traumatized at all by the compliance requirements (an online exam, registering the plane, and sticking the registration number on the plane), and he met them for all his planes.

Cheers.
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quorneng
In France the "registration" process is free, paid for by the government, but not so for the same process in the UK. £16.50 per pilot for 3 years although the scheme is intended to be 'cost neutral' so future charges could be higher depending on the number of registrations.
At the 800g French limit it is possible to build some quite serious planes, like my 1.27 m span AN2 at 723 g ready to go.
05Jan19a.jpg
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Lgel
Nothing is free, if there is no cost to the RC user, it means all the taxpayers are paying for it (even those who don't fly).
Cheers.
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quorneng
Agreed but it is surprising how different individual government approaches can be when supposedly meeting the same EU "drone" requirements!   
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