P-61 Black Widow with 6mm depron (floor XPS) - plans included - RC Groups
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Jan 25, 2016, 03:04 AM
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Build Log

P-61 Black Widow with 6mm depron (floor XPS) - plans included


Hello everyone.

Let me share with you my build story of a P61 Black Widow.
Actually the model is almost completed - but for future users it would be good to show the whole process - maybe someone would like to build a model like this in the future.

A few words of introduction:
This is supposed to be an ESA (Electric Simple Aircombat) model to participate in ESA WWII competitions. The competition is tough as most of the planes currently build are made from EPP. I didn't want to purchase a kit so I decided to build something my own.

Plan fits on 3 sheets of A4 ( I will upload it later into this thread).
Last edited by japim; May 18, 2017 at 08:26 AM.
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Jan 25, 2016, 04:40 AM
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Squall's Avatar
That's a pretty cool plane!
Jan 25, 2016, 05:18 AM
Allways the hard way!
georgy's Avatar
Dimentions? And power train? For those of us not familiar with the ESA WWII competitions...

I like it!
Jan 25, 2016, 05:41 AM
Registered User
Span: 1000 mm (max) - rest is scaled down.
Max AUW 600g (per ESA rules) - but I am assuming 450g - 460g for this particular frame.
Power train: 2 x Turnigy 2204-1400kV, Prop GWS 7x3.
ESC: 2 x Hyperion 12A
Servos: 3 x HXT 900 (but I may use 2 x HXT 500 on ailerons)
Batt: 1 x Zippy 3S 40C 1300 mAH (according to ESA rules the max pack for twins is 2500mAh - or 2 x 1250mAh ) but I have other single motor fighters that are using exactly 1300mAh (1350mAh mas per ESA rules) so I wanted to stay with one batt size for this type of competition.
Jan 25, 2016, 08:23 AM
Allways the hard way!
georgy's Avatar
Quote:
Originally Posted by japim
Span: 1000 mm (max) - rest is scaled down.
Max AUW 600g (per ESA rules) - but I am assuming 450g - 460g for this particular frame.
Power train: 2 x Turnigy 2204-1400kV, Prop GWS 7x3.
ESC: 2 x Hyperion 12A
Servos: 3 x HXT 900 (but I may use 2 x HXT 500 on ailerons)
Batt: 1 x Zippy 3S 40C 1300 mAH (according to ESA rules the max pack for twins is 2500mAh - or 2 x 1250mAh ) but I have other single motor fighters that are using exactly 1300mAh (1350mAh mas per ESA rules) so I wanted to stay with one batt size for this type of competition.
Sounds good. I also tend to go smaller on batts lately.. I found that the lighter weight often makes up for reduced batt capacity almost to the point of similar duration. BUT the bonus is better flying airplane... more forgiving and slower.
Jan 27, 2016, 01:11 PM
Slopeosapien
jonesymj's Avatar
Quote:
Originally Posted by japim
Plan fits on 3 sheets of A4 ( I will upload it later into this thread).
Please do! I would definitely build that!
Jan 28, 2016, 04:45 AM
Registered User
Let's start with printing the plans:
https://lh3.googleusercontent.com/-A...117_075523.jpg

Airfoil is "whatever hand had drawn: KFM I decided to go with KFM because you can still use it when building the model with EPP sheet (or dolar tree if you want)

You will need (2) sheets 500mm x 1000mm + a piece of styrofoam or XPS for the mid fuse. If you would like to build the center fuse from the 6mm plate you will need half sheet.

Some more details have been added to the print: (I will try to enclose all that info on the final PDF)
https://lh3.googleusercontent.com/-t...117_114609.jpg

Center fuse made from styrofoam (or 3D structure build from sheets) - can be glues from 7 layers. Engine pods were supposed to be more 3D - with side walls going wide by the engines and form a wide fuse ther - and you can still do it that way. But as this is technology testes I decided to go easy wa first.

Cut out plans have been glued onto 3mm HDF sheet to be used as a guide for hot wire:

https://lh5.googleusercontent.com/-s...117_115636.jpg

After rough styrofoam cutting I form a pile of elements with double sided tape and cut the final shape with a hot wire.
Do not go too fast as one guide means the wire will tend to bend over and you may finish with non equal pieces as the straight angle will go away.
https://lh3.googleusercontent.com/-o...117_230600.jpg

Weight of cut parts (with 2 x wood 6x6mm reinforcements): 207g

https://lh5.googleusercontent.com/-0...121_215257.jpg

Weight of all items: (wood 6x6mm 2 szt. HXT 3 x 9g, zippy 1300, 2 x ESC Hyperion 12A, 2 x TGY 2204-1400 kV, w/o paint, w/o glue w/o receiver): 437g
https://lh5.googleusercontent.com/-6...121_215506.jpg
Jan 29, 2016, 07:22 AM
Registered User
OK.

All elements are ready for assembly:

Take the center Fuse and make a cutout for the stiffener:
https://lh3.googleusercontent.com/-c...123_192838.jpg

Then glue the two side walls along (3 layers total - thickness is 18mm).
The outer panel should have the vertical stab trimmed.
the inner side wall to have a partially cut vertical stab to form a ledge where the horizontal stab will be attached to.
It also helps in future alignment.

The motor needs some extra gluing area so 8 extra necklace pieces have been cut and glued 2 on each side forming a total 42mm width:
https://lh3.googleusercontent.com/-S...124_215117.jpg
Motor mount is 3mm HDF with a C-cutout for routing the cables. I pre-drilled the holes and filled them with CA to harden them up.

I made a template from HDF to make the cuts for the wings in the fuse panels before gluing the panels together.
If the parts are cut with hot wire they match perfectly and after assembly they require only small sanding for step elimination, but the alignment of wing cutouts is more than good and there should be no problems with future wing assembly. I additionally deepened the cutouts for wings to glue a transition piece from 6mm EPP that will act as vibration damper and will assure some flexibility of the plane. How it works - we will see.

https://lh3.googleusercontent.com/-q...124_215539.jpg

Wings:
Cut the wing in one piece according to the dimensions shown on plans: center wing - 340 x 180 mm, 2 side panels 330 x 180 - total 1000mm wingspan.
Mark ailerons - 40mm deep - whole side wings length.
Mark the location of the engine fuses and the center pod.
Mark the wingtip cutout

KFM profile is straightforward - hard to mess it up.
Initially I thought to use KFM-4 in the center wing and KFM-2 in side panels.
Eventually I ended up with a blunt KFM-4 (nose rounded, no special forming/sanding) all span to reinforce the whole wing. We will see how it flies and handle tight turns.
If the blunt KFM-4 will be unacceptable I may grind the leading edge a little bit more. Or glue some 3mm depron to form KFM-5

https://lh3.googleusercontent.com/-t...124_104955.jpg

A first pre-assembly:
https://lh3.googleusercontent.com/-p...124_104429.jpg
Last edited by japim; Feb 01, 2016 at 06:29 AM.
Feb 05, 2016, 05:39 PM
Slopeosapien
jonesymj's Avatar
I'd definitely shape the leading edge, at the very least. It's worth the effort!

I'm going to get started on mine in the next couple of days here... Just gotta clear off the bench!
Feb 06, 2016, 04:51 PM
Registered User
She flies
Feb 06, 2016, 08:36 PM
Slopeosapien
jonesymj's Avatar
Niiice!
Feb 07, 2016, 01:15 AM
Registered User
Jonesymj: you are right. The profile should be sharpened. But I can tell you that with current airfoil she may not be the speed world record but flies very well. She is very stall resistant. Making loops almost behind her tail - like turning in a spot.

II have some movie footages so once I master them I will present her here soon. I still owe you guys plans in pdf and couple more sentences describing the build progress.
Feb 07, 2016, 02:03 AM
Slopeosapien
jonesymj's Avatar
I agree with you, japim! I'll take "flies a little slowly but really well" over "blistering fast but hard to control" any day!

Take your time getting stuff ready... I'm waiting on the motors to get here anyway, so no need to panic.
Enjoy your new airplane first!
Feb 07, 2016, 01:36 PM
Registered User
rajazo's Avatar
Looks great on the air , japim. Congratulations.
Post some photos of the Black Widow to see the finished painting... something interesting I can see on the published pictures
Feb 08, 2016, 02:20 AM
Registered User
Quick movie:
P61 Black Widow Profile Parkflyer ESA Maiden Flight (5 min 30 sec)


And some photos of the finished model:


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