Fixed-Wing vs. Multirotor Drone LiDAR

[@jet_flyer]

I completely see where you're coming from comparing fixed wing vs multi rotor in all the experience you have. But a lot of the issues you presented about lack of consistency in the data could be fixed by certain parameters you can adjust (at least with the autopolit software I use) and any accuracy issues I feel like would be resolved by being able to take a lot more passes thanks to the significantly longer flight times. Not doubting your experience and I agree with the issues you presented, just saying it seems like there are solutions to a lot of the issues you mentioned. Sure it would take more work to get it done with a fixed wing and those issues in mind, but you would be able to get a lot more data per flight.

[@FarmerFpv]

You presented no fixes. You're an armchair expert. Your post is meaningless. You criticize without posting any relevant information. What was the point of your post? Post a video with your claims?

[@RamiTamimi]

Thanks for the video! I definitely see how the fix wing system has some draw backs, it really should be used for certain jobs and not all jobs. Seems like a great drone type for larger projects.

[@Erdal_Gumus]

Nice to see dudes together...

[@jerseyshoredroneservices225]

A surveyor who hangs out with drone guys. That's cool👍

[@JackPratley-gr8mr]

K​

[@Erdal_Gumus]

Hello, Knoll. Based on my RGB photogrammetry experience, the performance and capabilities of fixed-wing drones (gliders) are highly topography-dependent. For example, in one of my research projects, I used Ebee Sensefly to model hydrothermal chimneys in a valley. Because of the collision avoidance, the drone flew so high that the results were marginally better than Google Earth imagery. As a result, gliders work best in relatively flat or uniform topographies, for the rest, a multirotor drone such as DJI Mavic or Matrice series would be more convenient.

[@IndianaDrones]

Exactly! I would go one step further and say flat terrain and below level 3 winds

[@VictoriaKean]

This is very informative Harrison. Thanks for sharing your experience with some of the differences between fixed wing and multirotor drones!

[@IndianaDrones]

My pleasure!

[@MDFire150]

All good points. As with all UAS missions, there's not going to be a one-size-fits-all solution. Having a few different types of UAS in your 'hanger' will allow you to pick the best tool for the specific job. Keep up the good work!!

[@IndianaDrones]

Thank you!

[@flowerpt]

Wow, I learned a lot, especially scenarios I'd never considered. Assuming fixed-wing is called for, why not use a gimbal to do automatic slew compensation? Or dynamically adjust air speed plus gimbal elevation to compensate for terrain/flightpath discrepancies? Seems like some algorithmic work could improves the workability of some tricky scenarios if you've gotta use fixed wing for other reasons.

[@IndianaDrones]

For the Wingtra their stated stall speed is 16 m/s. So anything below this then you lose lift and stall. So usually with the LiDAR payloads that I am talking about we are already going at the slowest airspeed we can. So any slower is impossible. I have made several gimbals for fixed wing and it is not practical for 2 reasons. 1) the added weight. The max payload weight is 900 grams. The LiDAR alone is already at or actually slightly above this. So the added wight of a gimbal is not feasible. If we change airframes to a more traditional dihedral wing design and increase the lift surface area ... larger aircrraft. Then we can support the added weight. But still the stall speed is usually stuck around this 16-22 m/s. I havent seen designs that is able to reduce the stall speed down to 6-10 m/s. I am sure there are some fundametal aerodynamic laws that might prevent this. Probs contained in the interplay with mass and gravity force pulling you down and the theoretical limit of upwards lift which is a property of the surface area and cross sectional shape of the aerofoil and the viscosity (Reynolds number) of the medium (air)(PV=nRT) ... I am not an expert at aerodynamics but I can reason that these input variables are what results in the physical limitations.

[@jerseyshoredroneservices225]

​@@IndianaDrones What about the hybrid drones that take off like a multi rotor and transition to fixed wing flight? Are you aware if anybody has programmed them to fly like a multi rotor when that's better given the circumstances and like a traditional fixed wing when that would be more appropriate?

[@b2zdrone826]

Spot on simple video with even more simple examples, nice sound effects lol, No but thank you for explaining this, hearing and seeing this does indeed put a lot of clarity on the major differences between the two Lidar platforms. Windcocking and overlap nightmares, never crossed my mind, and thats just one of the scenarios. Nice work!

[@IndianaDrones]

Thank you!

[@arhidrona]

Thank you for the informative insight on Fixed-Wing VS Multirotor Drone LiDAR. This is a helpful video and I hope you won't stop making this kind of educative funny graphics videos. Keep up the good work, mate! Let us know if you return to Romania, some of us would like to meet you :)

[@IndianaDrones]

Thanks, will do!

[@2252ryan]

Well done. Great detail and it makes great sense. Thanks for taking the time to prepare and present this video.

[@IndianaDrones]

You bet!

[@bowen3602]

So glad you made this video, keep it up!

[@IndianaDrones]

🫡 Thank you!

[@VictoriaKean]

I'd love to see videos in the future comparing processing software - speed, classification and noise cleanup, pricing

[@IndianaDrones]

Thanks for the feedback! I have some content on my channel regarding that, but will be doing some larger deep dives in the near future.

[@aaron6516]

This was a wonderful comparison of fixed wing vs multirotor. Thanks for putting this together!

[@IndianaDrones]

Glad it was helpful!

[@thiagoamaralf]

Amazing video, I think fixed wings are good for areas which does not give you flexibility on reaching by land, so you can cover a huge area without the need to move on land and find a spot to park and take off from, which with the mult rotor depending of the distance you are not able to fly because you would spend your battery on the way and you still need to come back.... etc and considering that you cannot reach the spot by land...

[@avdronebr]

Great Video, very informative!

[@IndianaDrones]

Thank you!

[@ArjayMartin]

Have the lidar rotate in relation to the crabbing...

[@AdrianMarina]

1:36 you say you went to Romania? I want to know more about that. Appreciate your efforts for educating everyone.

[@IndianaDrones]

Thanks for the feedback, Adrian!

[@wildandcurious_]

Excited to see how this video does!

[@IndianaDrones]

Same here! Pretty good so far!

[@nanirayavarapu8763]

The big limitation i noticed with Fixed wing or Multirotor (M3E) is the RC. As much as we can swap lot of batteries for my M3E, the RC battery life limits how much data can i collect in a day. For M350, there's a battery swap, but, not sure how many batteries will the RC lasts as it heats up a lot. and YES, YOU'RE RIGHT, Fixed wing is good for initial run for green field projects not more than that. Landing a fixed wing is sometimes pain. Thanks for the video. Hope you can expand in India.

[@jerseyshoredroneservices225]

You can use a long, heavy duty car charger extension to charge your transmitter while you're using it. Once upon a time my transmitter went dead. I was able to keep going with the car charger but that one only a very short wire so it was a real pain. Then I looked into it and found that you can buy a 15' long extension..

[@X85283]

It seems like it would be trivial, in fact I am sure it can be done in even hobbyist autopilots, to have the fixed wing plane fly at a fixed ground speed (obviously within reason depending on the windspeed and the power of the aircraft - if it is a 80mph wind or something you probably aren't flying). You can't fly a slower downwind groundspeed than windspeed + stall speed, I suppose, but on a properly designed drone that should be plenty slow for any windspeed that would be reasonable for flying. The climbing slower vs descending faster is the same issue, with ample power reserves it is absolutely something that a fixed wing can accommodate. At the extremes, a multirotor actually has the same issue, there is a certain point where a multirotor will need all of its power to climb to follow the terrain and will necessarily have to go slower while ascending... I feel a like a simple servo actuator on the LIDAR device would be able to keep the beam exactly perpendicular to the flight path regardless of any crabbing done by the plane. Again this would be easily set up in a hobby autopilot....

[@nunosantos8784]

Not to mention, that most of the fixed wing drones only update the flight line height at the end of the line, not following the terrain.

[@jacksons_drones]

It’s hard to get around physics!

[@IndianaDrones]

It sure is! 🌠📚

[@SamWelbourneGuitar]

Thanks, great insights.

[@IndianaDrones]

Anytime!

[@batosaitheslasher]

Hope you can show actual data sets of both multi copter & fix wing to support your argument.

[@IndianaDrones]

Sure! I’ll see if I can get some. It’s just logical though. Run through the thought experiment yourself and see if you can come up with a different conclusion. I’ve done the tests myself but it’s very logical. From the mandatory requirements of lift and the geometry of the airframe dictates their respective flight characteristics. You don’t see Boeing making hundreds of prototypes and crashing them. The physics of aerodynamics are solid.

[@Daniel-qr6sx]

For photogrammetry I believe fixed wings is the way to go, and you can also get huge areas photographed fast. Especially with something like the deltaquad EVO or eqvivalent. Helicopter drones are excellent for Lidar and smaller areas.

[@northsky6544]

Very good video Harris!

[@IndianaDrones]

Glad you enjoyed it!

[@beno177]

Well done..from a Pilot point of view there are far more issues that can happen flying a fix wing. so why a fixed wing...? Great for very large areas and flat and when there is no wind and your density altitude is just right. This affects all kinds of things, like air speed. Sooo way to many things to get over and on top of that the data is KEY.....GREAT data is great work. The more vagaries in the work...the data suffers. This work is tough enough with the work flow....so why make it harder with a fixed wing. H knows this and is trying to say GO DRONE not fixed wing 98% of the time.

[@IndianaDrones]

EXACTLY!

[@jamesbibel4031]

I'm sure you've seen a UAS fly into and with the wind. The speed is different, sometimes significantly.

[@BROC-7777]

This Save me some money and time.

[@AdamBomb403]

We had a client from the UK insist that we use a Wingtra on a project in Western Canada. We investigated but had concerns with the ability for the vehicle to accommodate for cold and strong winds. We eventually told them that we refuse to invest in it for this project. We have been collecting data on the same 1000 acres for 46 straight weeks during the project duration. We would probably be on our 3rd Wingtra if we decided to buy it.

[@IndianaDrones]

Exactly!

[@ArjayMartin]

Going up and down with the plane, if done with tilting the plane, would also affect the data significantly.

[@jerseyshoredroneservices225]

Unless the sensor is on a gimble like most quadcopters. However in another comment ID explained that his experiments with Gimbals showed that they're impractical for a few reasons.

[@IndianaDrones]

Can’t do the gimbal on these small fixed wing uas. The LiDAR payloads are already at 1 kg. And in the USA we have a limit of 55 lbs. so to make the aircraft bigger to accompany the additional payload weight then you add mass from the aircraft and then you need bigger batteries to drive bigger motors to get the flight time and then those add mass. So it quickly adds up. In my experience, going from a traditional fixed wing with 12 ft wing span and also a large rudder and elevator was still pushing the flight characteristics and wind happens. So you want to have extra room and not be flying super close to stall speeds I moved up to a 15 ft wingspan system and the extra lift surface area really helped the flight characteristics. But this system weighed close to 100 lbs. (Didn’t fly in USA)

[@ArjayMartin]

Wow, thanks for replying@@IndianaDrones

[@jerseyshoredroneservices225]

Why can't a fixed wing aircraft maintain consistent speed over the ground? Don't they have throttle control? Now I understand if there's a tail wind that would limit how slow they can go but in a crosswind or when climbing and descending why can't they just adjust throttle to maintain a consistent speed? When they (fixed wing) crab into the wind they don't do that to maintain lift over the wings, they do it to maintain their course. They could fly perpendicular to the wind but they would be blown off course.

[@IndianaDrones]

They do have throttle control but there is a minimum airspeed that must be maintained to generate lift or the wing will stall. Depending on the airframe used that speed changes. So if you were flying 5 m/s over the stall speed then yes, you could slow down by 5. But in practice with drone LiDAR payloads the stall speed of these small fixed wing systems is already pushing the limit of good data quality. So you are basically flying right above the stall speed and don’t Have any room to slow down.

[@jerseyshoredroneservices225]

@@IndianaDrones I understand, I was just thinking that when they have to climb they could add throttles and maintain their speed when they're descending they reduce throttle to maintain their speed while staying above stall speed all the time. The exception would be in a trailing wind situation then it would be difficult to slow down enough. Thanks for all the interesting and useful content you post. Even for those of us who aren't in the LIDAR game it's still useful and very interesting.

[@slavenlulic7736]

Bud idea was....

[@TaigiTWeseDiplomatFormosan]

ｏｋｏ

[@lolandypanda]

Well... mostly that is a bs. 10 minutes of bs. You have to mount lidar on both crafts using GIMBAL, otherwise, if you'll fly with a mrotor, your data would be very fuzzy, because random tilting and rolling of the drone to maintain a stable speed or blows of the wind, and battery sagging over time. Obiously the plane does have isues like you've mentioned, butgimbal solves all of them. And also due to waaay longer time of flight plane can do scanning only every second pass, which gives you consistent measurements...

[@jerseyshoredroneservices225]

Based on your experience which aircraft, gimble and lidar do you recommend?