The Phoenix Project: Reborn from the ashes of Stinger.

[Beaver5150]

This is another build thread of one of my ongoing contraptions, the left-over airframe from the Stinger Tri-copter I ran for a few months. I decided to resurrect it as an airplane similar to what I did in the building of The Mongrel Project.
It will be 0.80, or 4/5 scale from the size of Mongrel by the current calculations.
Single motor in tractor configuration, Emax Eco-II 2807/1700Kv/7x4.5x3 prop with airframe fitted for 3S/2200mAh or 4S/2300mAh LiPo packs. The thing should have plenty of power. Motor is factory rated at 1500g on 4S, and target weight is 1000g AUW.
The landing gear has been revised twice up to today, based on leftovers of a cheap RC rock crawler with hand fabricated axle and trailing link/sway bar. Wheels subject to change. I try to keep a wide track for stability, yet the geometry should absorb the harder landings I inflict when pulling STOL maneuvers. It also has to have the "Bigfoot" stance just to keep that 7" prop off the ground. The mud tires just look cool..... bush plane..... mudders..... Yee-Haw!
I have yet to settle on wing and tail profile, but wing will be 48x8, for a light wing load. All preliminary airframe and wing dimensions coincidentally fell into a 80% downscaled Mongrel after doing some comparative calculations, so I'm going to run with it.... Mongrel specs are working perfectly for me, so why change?

Here are the current photos of Phoenix.
Yes, that is a helicopter gyro on the back..... and it does work for fixed-wing if properly configured.
Nearly ready for wing and tail.

This thing is already functional by the Tx/Rx/FC and ESC setup. Static thrust test imminent.

 

[Bo123]

This is another build thread of one of my ongoing contraptions, the left-over airframe from the Stinger Tri-copter I ran for a few months. I decided to resurrect it as an airplane similar to what I did in the building of The Mongrel Project.
It will be 0.80, or 4/5 scale from the size of Mongrel by the current calculations.
Single motor in tractor configuration, Emax Eco-II 2807/1700Kv/7x4.5x3 prop with airframe fitted for 3S/2200mAh or 4S/2300mAh LiPo packs. The thing should have plenty of power. Motor is factory rated at 1500g on 4S, and target weight is 1000g AUW.
The landing gear has been revised twice up to today, based on leftovers of a cheap RC rock crawler with hand fabricated axle and trailing link/sway bar. Wheels subject to change. I try to keep a wide track for stability, yet the geometry should absorb the harder landings I inflict when pulling STOL maneuvers. It also has to have the "Bigfoot" stance just to keep that 7" prop off the ground. The mud tires just look cool..... bush plane..... mudders..... Yee-Haw!
I have yet to settle on wing and tail profile, but wing will be 48x8, for a light wing load. All preliminary airframe and wing dimensions coincidentally fell into a 80% downscaled Mongrel after doing some comparative calculations, so I'm going to run with it.... Mongrel specs are working perfectly for me, so why change?

Here are the current photos of Phoenix.
Yes, that is a helicopter gyro on the back..... and it does work for fixed-wing if properly configured.
Nearly ready for wing and tail.
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This thing is already functional by the Tx/Rx/FC and ESC setup. Static thrust test imminent.
View attachment 227216 View attachment 227217 View attachment 227218 View attachment 227219 View attachment 227220 View attachment 227221 View attachment 227222 View attachment 227223 View attachment 227224

Its amazing how compatible these airframes really are!

 

[Beaver5150]

Its amazing how compatible these airframes really are!

Carbon fiber.... if the holes don't match, drill new holes. Gotta love it.

 

[Beaver5150]

This isn't as much of a necessary build as was Mongrel. Since I have a solid everyday plane to fly now, I'm in no rush to get Phoenix in the air. I do spend an hour or two a day doing mock-ups, crunching numbers and what-not.
I was planning on using double layer cardboard for the wing as I did before on my first-ever scratch build due to built in rigidity, but after actually building the wing core, decided it was WAY too heavy. I'll just duplicate the design with foamboard and shave off 12 ounces. I'm trying to keep the same general wing load as Mongrel, keeping a more "glider like" feel when cruising slow and going for flight time or just hovering in the wind, but with nice agility and speed for aerobatics when I want to show off a little.

The tail section will be the left-over tail from decommissioned FT-Explorer, as it is exactly the same as the calculated dimensions I need.
I was going to post pics of the cardboard wing, but no point since it's too heavy to use.

One point on that wing design....
I'm going to hinge the trailing end of the wing to the airframe to make the front of the wing flip up like a car hood, to allow changing of LiPo packs inside the fuselage. it will be anchored at the front by a strong rubber O-ring like a rubber band across the bottom of the fuselage. I will be using a small amount of fiberglass inside the wing to add structural integrity, aside from the carbon fiber spar through the length of the wing at A-COG. If the plan works out, the wing will only weigh close to 10oz fully rigged as opposed to the raw cardboard core with no controll surfaces weighing 20oz. The weight of 4- 12g MG servos has been figured in (separate alierons/flaps or full length flaperon with dual servo drive each side) during overall weight calculations. I run the numbers daily as I change or modify anything in this preliminary stage.
If Mongrel is any indication, my process seems to be working so far. I've been flying it at least 30 minutes a day (night) for a few months now, and it's still going strong. (Knocking on wood)

 

[Beaver5150]

The Phoenix process is set to resume after having spent all weekend in the air with Mongrel for the holiday.
I have to finish it first before I start on a store bought Mini Skyhunter 1200mm plane.
As I may have said, cardboard is out, foamboard is back in...... too heavy.

 

[Beaver5150]

I've finally reproduced the cardboard wing core with a foamboard equivalent. The weight reduction wasn't as much as I would have liked, but it will work. I extended from 48 to 50 inches of span to make an even 500 sq-in wing.
I went with a standard symmetrical airfoil profile instead of the Kline Fogalman airfoil I used on Mongrel. I'm going for more of a low-drag/higher speed version of Mongrel but only using a single motor.
So far, AUW is looking to be 1200 grams at finish, but since things are designed to a specific power system weight of 4S/2300mAh Lipo, 2807/1700Kv motor with 7x4.5x3 prop rated at 2100g static thrust, the power to weight ratio should still come close to 2:1...... plenty of power to play with.
I don't like that I keep overshooting my target AUW and have to increase wing area to compensate, but building the wing last seems to be working. At least that way, I can compensate for more than expected airframe weight.
I will post some pics this evening

 

[Beaver5150]

Okay, I'm slacking on the pics.
Actually put the thing in the air and run a pack or two, but CG is off. It had a bad nose-up going on. I also may have overshot the incident angle a few degrees. Will need to adjust.

 

[Beaver5150]

This thing is already in the air now, but will be going through changes. First batch of flights were squirrelly. CG was a bit too far back, so I put a bigger 2814 motor and 8x4 prop on for non parasitic nose weight, and also effectively increased flight time. I will be adding a better ESC, from 25a to 45a due to a series of full throttle power drop-outs.
Drag seems minimal with the standard symmetrical airfoil on 50x10 wing.
Stall is a bit sharper than with a KFm airfoil.
Tail surface is cut and repurposed from an FT-Explorer that I wore-out. It will be redesigned, as Phoenix already needs more V-stab/rudder authority.
The one thing that did make it fly well in current configuration is the Aura5-lite I borrowed from Mongrel temporarily........ So far, best "plane brain" I own.
Here are the pics so far...... .

 

[skymaster]

This thing is already in the air now, but will be going through changes. First batch of flights were squirrelly. CG was a bit too far back, so I put a bigger 2814 motor and 8x4 prop on for non parasitic nose weight, and also effectively increased flight time. I will be adding a better ESC, from 25a to 45a due to a series of full throttle power drop-outs.
Drag seems minimal with the standard symmetrical airfoil on 50x10 wing.
Stall is a bit sharper than with a KFm airfoil.
Tail surface is cut and repurposed from an FT-Explorer that I wore-out. It will be redesigned, as Phoenix already needs more V-stab/rudder authority.
The one thing that did make it fly well in current configuration is the Aura5-lite I borrowed from Mongrel temporarily........ So far, best "plane brain" I own.
Here are the pics so far...... .
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do you have flaps on is that why you have four servos on the wing. frame looks awesome

 

[Baron VonHelton]

This thing is already in the air now, but will be going through changes. First batch of flights were squirrelly. CG was a bit too far back, so I put a bigger 2814 motor and 8x4 prop on for non parasitic nose weight, and also effectively increased flight time. I will be adding a better ESC, from 25a to 45a due to a series of full throttle power drop-outs.
Drag seems minimal with the standard symmetrical airfoil on 50x10 wing.
Stall is a bit sharper than with a KFm airfoil.
Tail surface is cut and repurposed from an FT-Explorer that I wore-out. It will be redesigned, as Phoenix already needs more V-stab/rudder authority.
The one thing that did make it fly well in current configuration is the Aura5-lite I borrowed from Mongrel temporarily........ So far, best "plane brain" I own.
Here are the pics so far...... .
View attachment 228564 View attachment 228565 View attachment 228566 View attachment 228567 View attachment 228568 View attachment 228569 View attachment 228570 View attachment 228571 View attachment 228564 View attachment 228565

We've had the flight stick, skinny stick, glow stick, etc........

I guess this will be the skeleton stick?

 

[Beaver5150]

We've had the flight stick, skinny stick, glow stick, etc........

I guess this will be the skeleton stick?

Good one!

 

[Beaver5150]

do you have flaps on is that why you have four servos on the wing. frame looks awesome

Flaperons actually.... doubled and synchronized the servos to spread the load across the longer control surface.
I could have gone with separate flaps, but didn't.

 

[Beaver5150]

With the lower drag profile of that skinny frame and the symmetrical airfoil, the thing caught a light tail wind on one run and I didn't think I'd ever get the thing down on the ground after throttle cut.... . It didn't want to do anything but glide!

 

[Beaver5150]

What a day!
So far, so good..... 5 more full flights, no major problems, only a few near stalls and a botched landing on video.......
Phoenix is officially risen from the ashes and flying within expected parameters.

Current stats: (approx)
AUW 1160g/41oz/2.5lbs (4S/2300mAh)
No LiPo: 935g/33oz/2.0lbs
2814/950Kv drone motor with 8x5 prop
10 to 15 min flights to 15.5v to 15.7 average discharge.

Absolute max airtime to low voltage alarm 20 minutes (nominal flying with occasional bursts of full throttle. Not my normal LiPo routine, but I needed to establish a base timetable.

Power drain is near half that of Mongrel and expected since Mongrel runs 2 of the same type motors as Phoenix.
Points to improve:
Build a proper tail assembly. The repurposed one is too worn. Vertical and rudder need to be increased in size. Elevator is fine.
Structural rigidity issue at fuselage to tail joint needs to be reinforced due to damage "in it's previous life". In other words, carbon fiber patching.
The above 2 issues are due to a tail oscillation at high speed which is triggered also by too much gain on the tail gyro, which I simply haven't bothered with just yet. It may be seen in the video I'm about to post.
Landing gear is functional, but not final.

Aside from a few minor flaws, this bird is shaping up quickly. It's It's almost like flying my 41" Extra 330s, but with a little "Mongrel feel" to it. And this is only day 2.

The video:
Shot with my Runcam2 Split on a modified tripod mount.... fisheye lens.
This plane is so quiet, you actually can't hear it over the crickets and frogs unless it's within 20 feet, cruising at half throttle. The isolated motor mount worked...... You may actually have to turn the volume up on this one!

 

[Baron VonHelton]

What a day!
So far, so good..... 5 more full flights, no major problems, only a few near stalls and a botched landing on video.......
Phoenix is officially risen from the ashes and flying within expected parameters.

Now if I can just get my planes to fly that long.......

 

[Beaver5150]

4 flights, the first ending up in a tree because I had ailerons plugged in wrong even though preflight showed them correct after removing wing last night. Some careful poking and prodding with a pole brought it down, with no damage..... flight resumed a hot minute after correcting my error.
A few structural mods last night worked as planned, and the plane flew well today for the last round of "tests" before I put bigger tail feathers on this bird.
I will also be rebuilding the landing gear and possibly installing some cowling, and relocating the flight controller to reduce drag. This all has to be done before I can begin installing the inevitable LEDs as on Mongrel.
And now, to put my Aura5 back in Mongrel whole Phoenix is parked.........

 

[Bo123]

I think this is definately on of the most interesting and orginial designs out there. I mean who uses helicopter parts for planes! Great job!

 

[Beaver5150]

Landing gear version 2 complete. Less weight, less drag, and hopefully a bit more durable.
It will do until I get some actual 1/10 scale truck shocks on it. I can't bring myself to borrow them from my Slash.
Did I mention that the forward trailing arm setup is the stainless steel arm from a fuel gauge sending unit? The rear part is only coat-hanger wire, but is also an impact absorber on hard landings. Just bend it back and keep flying..... or in this instance, rolling.
Tail rebuild is next.

 

[Beaver5150]

I think this is definately on of the most interesting and orginial designs out there. I mean who uses helicopter parts for planes! Great job!

The Mongrel plane I built a few months ago is based on an entire Blade 450-3D heli frame. (See the thread in this section)
Phoenix uses an MSH Protos tail boom block, but the rest is mainly salvage drone frames and parts.
In any case, it's not really scratch building as much as it is repurposing and reverse engineering, except for wings and tails..... those are all me.

 

[Beaver5150]

Okay..... the tail is rebuilt. CG is a hair too far back now, likes to pitch up without auto-level. I'll get that sorted out soon enough.
No issues other than that, from the two flights I just made. Flies great with auto-level engaged, slow or fast. Landing gear upgrade is working well so far. I'll get a few more flights in this evening if it isn't raining.