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JH Speed Deamon - a foamboard pylon racer

FAI-F1D

Free Flight Indoorist
#1
Some years ago there was some interest thrown around about seeing just how fast a foamboard plane could go. You can read some of that here:
https://forum.flitetest.com/index.php?threads/foamboard-ultimate-speed-challenge.29898/

A couple years have passed, and @Mid7night and @Baby Brit have been egging me on (some say @wilmracer started it) with crazy shenanigans. Well, time to throw caution (and all the rules from that old thread) to the wind.

So with naming thanks to Baby Brit, I present to you the Speed Deamon, compliments of J&H Aerospace R&D. This entire thing is made possible by the new FT Radial motors which are absolutely insane in the amount of abuse they can take. Thanks to their robustness, most of the design problem revolves around cramming enough battery in the plane to satisfy the motor's thirsty appetite!

Since the fastest electric planes currently available are form the F3S competitions in Germany, I figured and HK Speedwings design could provide the basic planform:
Monster1.1_1_ml.jpg

I scratched this thing out in Sketchup, using measurements from motor and battery as my primary constraints. I also wanted it to fit on one sheet of DTFB if possible and feature some form of swappable pod so that access to the electronics would be possible. This is important since pylon birds are infamous for being packed to the limit. This aircraft is no different.

So the result looks something like this:
FTpylon1.png

Span is 28", power is a 3s2200 up to a 6s1200, FT2207-1750 Radial, and a 5x5 prop for basic flying (ecalc says up to a 5.5x6.25 on 6s, for 900W total).
 
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FAI-F1D

Free Flight Indoorist
#2
Beta release plans: https://drive.google.com/open?id=1T-ak19vVqo3z_P2Tk7kDnM18dbnsBfhl

Specs:
Wing Span 28 inches
Length 25 inches
Center of Gravity 1.25-1.625 inches aft of wing root LE
Wing Area 141 square inches
All Up Weight 18 ounces
Wing Loading 18.4 oz. / sq. ft.

Skill required
Build skill level: 2 - You've built an FT plane before
Pilot skill level: 3 - You've mastered ailerons and basic aerobatics

Electronics
4 channel rx
50A esc minimum, rated for cell count desired (3-6s)
Turnigy 2826-2200 kv
APC 5x5 or 5.25x6.25 prop
3x 9g servos
Transmitter capable of dual aileron mixing
4s 1800 30C - 6s 1300 50C lipo (recommend Lumineer long pack 6s 1300)

Recommended throws:
Ailerons: +/- 25̊ @ 30% expo
Elevator: +/- 20̊ @ 50% expo

WARNING!!!
With the recommended 6s setup, this is a very fast airplane that pushes the structural limitations of foamboard. It is capable of speeds well in excess of 100 mph, and foam wing spars cannot take the flight loads imposed by those speeds. For any flight expected to exceed 75 mph, you need to install a 3/16" CF tube in front of the foam wing spar during assembly as shown in the build videos. You may also use a piece of wooden yardstick, although this will change the airfoil shape slightly and may reduce top speeds a little.
 

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FAI-F1D

Free Flight Indoorist
#4
Ok, some development items...

I was able to arrange everything on one sheet of DTFB:
FTpylon2.png

At the moment I'm rolling with a proprietary firewall using plywood reinforcements to get everything up to the strength values I want. 900W is a lot of power and I don't like the possibility of things coming loose (says the idiot who's holding the whole thing on with a skewer).
deamon plywood.png
 

FAI-F1D

Free Flight Indoorist
#7
So some build progress...

This is a really easy build considering what I'm trying to do with it. Hopefully it'll deliver.
IMG_20190520_181025191.jpg
IMG_20190520_181033759.jpg
IMG_20190520_193252656.jpg IMG_20190520_193245999.jpg IMG_20190520_193243170.jpg IMG_20190520_182214930.jpg
 
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FAI-F1D

Free Flight Indoorist
#8
And the sprint to completion. I did fly it like this. The 5x5 three blade held it back a bit on 3s but the maiden was almost boring. Just needed some down trim.
IMG_20190520_200208908.jpg IMG_20190520_195330029.jpg IMG_20190520_195318891.jpg IMG_20190520_193857522.jpg
IMG_20190520_203436459.jpg
 
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Hai-Lee

Old and Bold RC PILOT
#10
Nice work do far and I will be keeping an eye on this thread.

I do have a concern with such a thick flat bottomed wing profile being forced through the air at a very high speed especially when the motor thrust line is so far removed from the centre of drag. You may experience a severe nose up at very high speed and the chance of generating a control reversal situation. I HOPE I AM WRONG!!!

Previously i dabbled with a 1/2A design and built it out of FB. My rendition was/is grossly over powered, (only on 3S), and it uses a wing on the thrust line with a symmetrical(ish), wing profile. Even at my relatively low top speed, (with respect to your build), the control sensitivity builds up markedly and caution is required as well as dual rates. On the first attempt I managed to fold the wing in a sudden high speed turn/loop, (inverted).

Have fun!
 

FAI-F1D

Free Flight Indoorist
#12
Build videos are now live for the beta release, plus plans for same. All the photos up to this point are for the alpha version, and the flight video for the alpha version is uploading.
 

FAI-F1D

Free Flight Indoorist
#13
So it flew...

OH NO!!!!
IMG_20190521_111307788.jpg

IMG_20190521_111816212.jpg

So...don't go above 75 mph with the foam wing spar. You could put a piece of yardstick in there, or...
IMG_20190521_134418798.jpg

In the meantime, enjoy flight footage:
 

Tench745

Well-known member
#14
23 minutes of build?! Having a laser cutter must be nice. This hobby would be really dangerous for me (but probably a lot more fun) if I had a CNC cutter.
Enjoying the experiment!
 

FAI-F1D

Free Flight Indoorist
#15
Got the new one built. Screaming howling madness awaits!
IMG_20190521_152251904.jpg

I got this really bright idea to try flying on 3s and a 7x10 prop. Ecalc said it would work, right? Yeah...that's smoke coming out of the vent. It's not coming from the battery.
IMG_20190522_113128322 (1).jpg

I actually dug one of the tiny components seen below out of the motor's stator (yes, the motor is toast too).
IMG_20190522_123916692.jpg

Pretty significant damage to the internal structure of the paper and foam. :(
IMG_20190522_123555932.jpg

Yeah I just taped it up, put a Turnigy 2826-2200 on there, and a big old 60A esc.
IMG_20190522_130439671.jpg

That stupid little prop was on there because I was scared of what happened before. Well, it only got me into the high 70's on 4s, so I decided to go for broke. Time for a 5.25x6.25 APC. 4s got me up to 94 mph. Still not good enough.

Let's go 6s!!!
IMG_20190522_101417645.jpg

Oh, while I was at it, I shipped a kit for the Speed Deamon and @Mid7night 's Yellow Jacket V1 to @Baby Brit
IMG_20190523_091011516.jpg

So what did the 6s Lipo do? Well you'll just have to watch the video!

 

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#19
So...this project has given birth to another...
View attachment 133094

Join me here for the development of the Hot Deamon!
Got the new one built. Screaming howling madness awaits!
View attachment 133030

I got this really bright idea to try flying on 3s and a 7x10 prop. Ecalc said it would work, right? Yeah...that's smoke coming out of the vent. It's not coming from the battery.
View attachment 133069

I actually dug one of the tiny components seen below out of the motor's stator (yes, the motor is toast too).
View attachment 133047

Pretty significant damage to the internal structure of the paper and foam. :(
View attachment 133048

Yeah I just taped it up, put a Turnigy 2826-2200 on there, and a big old 60A esc.
View attachment 133049

That stupid little prop was on there because I was scared of what happened before. Well, it only got me into the high 70's on 4s, so I decided to go for broke. Time for a 5.25x6.25 APC. 4s got me up to 94 mph. Still not good enough.

Let's go 6s!!!
View attachment 133070

Oh, while I was at it, I shipped a kit for the Speed Deamon and @Mid7night 's Yellow Jacket V1 to @Baby Brit
View attachment 133050

So what did the 6s Lipo do? Well you'll just have to watch the video!

Josh - I have downloaded the dxf file and used an online converter to make it a pdf for printing, however, when measuring the pdf it is saying its 66 inches wide so the scaling has got messed up somewhat. Could you please point me to an already converted pdf or let me know how this can be done correctly. Kind Regards Craig....
 

FAI-F1D

Free Flight Indoorist
#20
Josh - I have downloaded the dxf file and used an online converter to make it a pdf for printing, however, when measuring the pdf it is saying its 66 inches wide so the scaling has got messed up somewhat. Could you please point me to an already converted pdf or let me know how this can be done correctly. Kind Regards Craig....
Craig,

That's...fun... Well anyway, there should be a .pdf in the folder. And in case it's not showing, I've attached it here.
 

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