Local customer chases a world record

[Wayne]

We have enjoyed our visits from Keaton for the last few years, and he has been working several years on a flying wing design to set a new world record for an endurance flight. We have enjoyed the updates when he visits the shop and I thought you all might enjoy it too. Right now the forum is not allowing me to pull up his account, but should be able to get him on here very soon. He has done some intersting things.

The current record is about 10 years old, and battery and solar has seen some nice improvements. The power system is interesting as it draws about 30 watts, and the flight will remain below 400 feet AGL and I think he said the VNE (max speed) of the airframe is about 30 mph.

 

[Wayne]

@KeatonHare - OK - The forum finally updated and I can tag him here. He should pop up and share some more details on the project.

 

[KeatonHare]

We have enjoyed our visits from Keaton for the last few years, and he has been working several years on a flying wing design to set a new world record for an endurance flight. We have enjoyed the updates when he visits the shop and I thought you all might enjoy it too. Right now the forum is not allowing me to pull up his account, but should be able to get him on here very soon. He has done some intersting things.

The current record is about 10 years old, and battery and solar has seen some nice improvements. The power system is interesting as it draws about 30 watts, and the flight will remain below 400 feet AGL and I think he said the VNE (max speed) of the airframe is about 30 mph.

Hi all! for the past three years or so, I've been working on breaking the world endurance record for sub 55lb UAV's (Currently 81 hours set by AtlantikSolar from ETH Zurich). I'm using a Prandtl wing (you might have heard about it from @Red ) with a 16 foot wingspan and a single 239KV motor, with a 16x15 prop. The record involves flying for 14 hours overnight on battery power, then recharging every day whilst flying. I'm aiming for about 100 hours total duration. The basic setup of the wing is as follows; 3D printed joiners between spars, which are laser cut 3/32nds basswood, and homemade I-beams running the length of the wing. The wing is covered with doculam, and I'm using a 3d printed fuselage and a pusher prop at the end of a carbon rod to balance CG. I'm now on what I hope is the final of 11-15 full redesigns, and hopefully plan to build and flight test in the next 3 weeks or so. Feel free to post questions about the project below! This is my first project at this scale so very interested in feedback. I've attached some renders of the latest version below

 

[Wayne]

Prandtl sure make for an interesting wing. The tip ribs look so funny to my eye.

 

[jure]

like your concept, tailless airframe also removes tail drag and weight.

why not a tractor configuration , for more efficiency ?
are you going to use LiPo or LiIon batteries ?
solar cell efficiency and weight look to be very important.

PS: attached some links and a file relevant to the AtlantikSolar

AtlantikSolar website
AtlantikSolar publication link

 

[Doc James Hammond]

Excellent project! What size are you going for?

I think it will be really good.

Doc.

 

[KeatonHare]

like your concept, tailless airframe also removes tail drag and weight.

why not a tractor configuration , for more efficiency ?
are you going to use LiPo or LiIon batteries ?
solar cell efficiency and weight look to be very important.

PS: attached some links and a file relevant to the AtlantikSolar

AtlantikSolar website
AtlantikSolar publication link


View attachment 23916

Hi! sorry for the late reply, been busy building the latest version. I went with a pusher for CG and stability reasons, and I've extended it far to the rear of the fuselage to minimize losses to dirty air. I'm using 3s6p 6000Mah Lion cells to fly through the night, and I should have ~200w peak solar production. AUW target is 8-10lbs all up for a 16ft wing

 

[KeatonHare]

Excellent project! What size are you going for?

I think it will be really good.

Doc.

sorry for the late response! I'm aiming for a 16ft wingspan, the last version flew great at that span so this one should have no problems, and I've made some adjustments to get stronger I-beam spars

 

[jure]

... I'm using 3s6p 6000Mah Lion cells to fly through the night, and I should have ~200w peak solar production. AUW target is 8-10lbs all up for a 16ft wing

my concern was that LiIon batteries bring a weight penalty with them, compared to LiPo batteries.

 

[KeatonHare]

my concern was that LiIon batteries bring a weight penalty with them, compared to LiPo batteries.

Lion cells actually have much higher energy density, they just don't output quite as much amperage

 

[Wayne]

I think Keaton is using the newer "tabless" cells?? Lion is also available in pouched cells these days, seems the new pouch and the tabless are VERY comparable in the hand tool market. Both offer improved performance and efficiency.

We stock a tabless cell here at Aloft:

EVE INR 21700-40PL 4000mAh Li Ion -Tabless Structure upto 70 amps!

This Eve cell supports up to 70 amps and features a huge capacity. Yes, 70 amps! These high capacity Lithium Ion batteries feature a tabless structure to obtain lower impedance and higher sustained power. A constant amp rating of 70 is impressive! The EVE INR21700-40PL is a popular choice for...

alofthobbies.com

Should anyone ever need a cell we do not stock - please reach out to us. We can usually get them and offer a very fair price. Battery tech is always fun to follow.

 

[KeatonHare]

I think Keaton is using the newer "tabless" cells?? Lion is also available in pouched cells these days, seems the new pouch and the tabless are VERY comparable in the hand tool market. Both offer improved performance and efficiency.

We stock a tabless cell here at Aloft:

EVE INR 21700-40PL 4000mAh Li Ion -Tabless Structure upto 70 amps!

This Eve cell supports up to 70 amps and features a huge capacity. Yes, 70 amps! These high capacity Lithium Ion batteries feature a tabless structure to obtain lower impedance and higher sustained power. A constant amp rating of 70 is impressive! The EVE INR21700-40PL is a popular choice for...

alofthobbies.com

Should anyone ever need a cell we do not stock - please reach out to us. We can usually get them and offer a very fair price. Battery tech is always fun to follow.

I'm actually still using Tabbed cells! The Molicel P50B - They're fantastic - 5000Mah and 72g with a 60A max discharge rate