Solved Heavy FT explorer with large wing

[Mark408]

I recently made a larger wing for the FT Explorer. I was using the trainer wing (8 inch chord, 57 inch wingspan, 456 Inches squared wing area) for my autonomous Ardupilot setup. The AUW then was 930 Grams. I'm sure it would still fly but decided to make a new wing to increase the aspect ratio and add aileron controls. So I increased the wingpsan of the Sport wing until I had a large wing with a 7 inch chord and 75 inch winspan (525 Inches squared wing area). I also added some winglets for good measure. The AUW now is 1000 grams. I am using a 2200 mah 3S lipo, 1000 kv motor, 10/4.5 prop (extended firewall), Pixhawk PX4 2.4.6, Raspberry Pi zero, Raspberry Pi cam, and a AC56 Wifi adapter (Using it as my Telemetry and Video TX via OpenHD. This is obviously alot of gear. So will it fly fine?

(Sorry if my thread is in the wrong place, I'm new to the forum and I'm pretty dumb. Please correct me if I'm wrong)

 

[quorneng]

Mark408
Without knowing the measured power (Watts) that your motor/prop/battery can provide it is hard to say how well it might fly.
To have some reserve of power you need to have about 220W at full power which would correspond to the motor drawing some 22 amps.

Just as an aside increasing the aspect ratio of a wing does not guarantee a better performance as, assuming the wing has the same strength, it will also be a bit heavier. More weight in a plane makes it fly faster which needs more power just to fly straight and level.
Remember super efficient high aspect ratio glider wings are aerodynamically very efficient but they are relatively heavy and don't have to carry much useful payload.

 

[Mark408]

Thanks for the quick reply. The fuselage (All the tech and fuselage without the wings) weighs 650 grams. The Trainer wing weighs 230 grams with a wing area of 456 inches squared, with my longer trainer wing with winglets weighing 300 grams (servos add 20 grams). As for amp draw that's hard to find out. Mission planner says full throttle pulls 9 amps (not well calibrated) when I'm holding the plane still, this most probably changes in the air. Should I just try to maiden it?

 

[mrjdstewart]

i think my modified explorer wing was just about as big. i was running a gopro3, separate fpv setup, plus a 4S-2200. it was not light...

my first wing snapped so i reinforced with carbon wing spar from an old crashed eflite radian i had been given. seems to have solved problem.

good luck,

me

 

[Tench745]

I recently made a larger wing for the FT Explorer. I was using the trainer wing (8 inch chord, 57 inch wingspan, 456 Inches squared wing area) for my autonomous Ardupilot setup. The AUW then was 930 Grams. I'm sure it would still fly but decided to make a new wing to increase the aspect ratio and add aileron controls. So I increased the wingpsan of the Sport wing until I had a large wing with a 7 inch chord and 75 inch winspan (525 Inches squared wing area). I also added some winglets for good measure. The AUW now is 1000 grams. I am using a 2200 mah 3S lipo, 1000 kv motor, 10/4.5 prop (extended firewall), Pixhawk PX4 2.4.6, Raspberry Pi zero, Raspberry Pi cam, and a AC56 Wifi adapter (Using it as my Telemetry and Video TX via OpenHD. This is obviously alot of gear. So will it fly fine?

(Sorry if my thread is in the wrong place, I'm new to the forum and I'm pretty dumb. Please correct me if I'm wrong)

It looks like you increased the aspect ratio and wing area, but you also increased weight. In doing so the wing loading only changed from 10.4oz/square-foot to 9.67oz/sqft. That drops your estimated stall speed from 15.9mph to 15.4mph. Not much of a difference. That prop and motor combo, assuming 80% efficiency, has an approximate max speed of 41mph. As long as you have enough thrust it should fly just fine.

Keep in mind that roll and yaw rates will be affected by the longer wing and you may want to enlarge the vertical tail to increase yaw stability. Test flights will show what needs to change.

 

[Mark408]

i think my modified explorer wing was just about as big. i was running a gopro3, separate fpv setup, plus a 4S-2200. it was not light...

my first wing snapped so i reinforced with carbon wing spar from an old crashed eflite radian i had been given. seems to have solved problem.

good luck,

me

Wow, good thing I put 2 wooden dowels inside as a spar to reinforce the center. I'm less anxious of the maiden now. The 10/4.5 prop should give me plenty of power to fly with the big wings. Thanks!

 

[Mark408]

It looks like you increased the aspect ratio and wing area, but you also increased weight. In doing so the wing loading only changed from 10.4oz/square-foot to 9.67oz/sqft. That drops your estimated stall speed from 15.9mph to 15.4mph. Not much of a difference. That prop and motor combo, assuming 80% efficiency, has an approximate max speed of 41mph. As long as you have enough thrust it should fly just fine.

Keep in mind that roll and yaw rates will be affected by the longer wing and you may want to enlarge the vertical tail to increase yaw stability. Test flights will show what needs to change.

Thanks for the input. I wanted to add aileron control to help the Pixhawk since elevator and rudder might be limiting how effective the Ardupilot may function in crosswind and turns. I thought that if the Trainer wing would decrease the chord and add the weight of the servos, I might aswell make it longer and add winglets. Thanks, and I'll see how the maiden goes.

 

[skymaster]

I recently made a larger wing for the FT Explorer. I was using the trainer wing (8 inch chord, 57 inch wingspan, 456 Inches squared wing area) for my autonomous Ardupilot setup. The AUW then was 930 Grams. I'm sure it would still fly but decided to make a new wing to increase the aspect ratio and add aileron controls. So I increased the wingpsan of the Sport wing until I had a large wing with a 7 inch chord and 75 inch winspan (525 Inches squared wing area). I also added some winglets for good measure. The AUW now is 1000 grams. I am using a 2200 mah 3S lipo, 1000 kv motor, 10/4.5 prop (extended firewall), Pixhawk PX4 2.4.6, Raspberry Pi zero, Raspberry Pi cam, and a AC56 Wifi adapter (Using it as my Telemetry and Video TX via OpenHD. This is obviously alot of gear. So will it fly fine?

(Sorry if my thread is in the wrong place, I'm new to the forum and I'm pretty dumb. Please correct me if I'm wrong)

we are not picky here so express your mind. we like to hear every one's ideas and adventures

 

[Mark408]

Late update: The FT explorer did fly! And it flew very well. I flew it at empty airfield and used the "FBWA" mode in Mission planner to give some stabilization. I will try the autonomous modes soon but I'm happy with the current results (Note: the total wing area is actually 562 which gives it a reasonable wing loading of 8.8 oz/sq ft.

Almost hit a bird here.

 

[SSgt Duramax]

Late update: The FT explorer did fly! And it flew very well. I flew it at empty airfield and used the "FBWA" mode in Mission planner to give some stabilization. I will try the autonomous modes soon but I'm happy with the current results (Note: the total wing area is actually 562 which gives it a reasonable wing loading of 8.8 oz/sq ft.

View attachment 221815
Almost hit a bird here.

Glad you had a good flight! Those fly good once you get them balanced out and ensure the thrust angle is good. I had built one with a 60" wing that had a 7" chord and a carbon arrow spar. I flew it with a 4500 mah in the nose.

 

[Mark408]

Glad you had a good flight! Those fly good once you get them balanced out and ensure the thrust angle is good. I had built one with a 60" wing that had a 7" chord and a carbon arrow spar. I flew it with a 4500 mah in the nose.

Spar is the only thing that worries me a lil bit, I rebuilt the entire airframe and wing (Brought my weight down to 940 grams AUW, same 75" wing design). I used a 1/4 inch x 40 inch wooden dowel spar, a popsicle stick, and a smaller 1/4 inch 10 wooden dowel spar in the middle. This along side the foam spar and already pretty rigid wing, I think it shouldn't have any possibility of wing snapping while doing an autonomous mission (2g turn at most I would expect). Is this enough rigidity?

 

[SSgt Duramax]

Spar is the only thing that worries me a lil bit, I rebuilt the entire airframe and wing (Brought my weight down to 940 grams AUW, same 75" wing design). I used a 1/4 inch x 40 inch wooden dowel spar, a popsicle stick, and a smaller 1/4 inch 10 wooden dowel spar in the middle. This along side the foam spar and already pretty rigid wing, I think it shouldn't have any possibility of wing snapping while doing an autonomous mission (2g turn at most I would expect). Is this enough rigidity?

Considering I fly a 60 inch plane in much the same fashion that weighs up to 4lb fully equipped with just a foam board spar, I would say youll be fine. The center of my wing is reinforced with gorilla duct tape.

I was also able to pick up a 30lb kettle bell with 2 quarter inch foot long square birch dowels testing for a 4-5lb plank I am making. If yours are oak even better.

The gopro, fpv nose, and a brick battery add considerable weight. Flies in 30mph gusts and Ive been known to rip vertical in it and to tactical landings.

 

[Beaver5150]

You're doing what I did. I killed the sport Ft-Exp wing right off. It cracked at the servo pocket underneath one side during a hard pull-up at speed. I made a 60x10 foamboard Kfm-3 wing but I used an oak spar and too much glue, so it was kinda heavy. The weight didn't bother it too much, the thing would still float like a butterfly with flaps down. Pulled a near 700ft emergency glide-down once from around 80ft up... weighing 2.5 to 3 lbs at the time.
I'm not flying an FtExp anymore, but I just duplicated the 60x10 (60x9 actually) wing on my "Mongrel" build, it's half the weight as before, and I love it 3 flights in! (Balsa this time, less glue)
You get a good flight controller with auto-leveling on your FtExp and you'll love it.
Here's a vid of my 60" Exp. I rigged for lights when I built the first 60 wing, part of the extra weight I guess.

 

[SSgt Duramax]

You're doing what I did. I killed the sport Ft-Exp wing right off. It cracked at the servo pocket underneath one side during a hard pull-up at speed. I made a 60x10 foamboard Kfm-3 wing but I used an oak spar and too much glue, so it was kinda heavy. The weight didn't bother it too much, the thing would still float like a butterfly with flaps down. Pulled a near 700ft emergency glide-down once from around 80ft up... weighing 2.5 to 3 lbs at the time.
I'm not flying an FtExp anymore, but I just duplicated the 60x10 (60x9 actually) wing on my "Mongrel" build, it's half the weight as before, and I love it 3 flights in! (Balsa this time, less glue)
You get a good flight controller with auto-leveling on your FtExp and you'll love it.
Here's a vid of my 60" Exp. I rigged for lights when I built the first 60 wing, part of the extra weight I guess.

If you don't need OSD and other fancy stuff, the little $30 dollar sparrow flight controllers with GPS have geofencing, RTH, and a very effective gyro. I would have one on every plane within reason if it weren't price prohibitive. The only negative about it that kind of drives me nuts is they don't have an "acro" stabilized mode. It is either heading hold, geofencing mode, or off. So if you want to be a crazy and go vertical to try to intercept a bird, you are going in manual or you are tugging the heck out of the sticks to make it do anything.