Helipad on car hood?

[CDSkeeles]

A2s owner here.

Looking to have a conversation with the group about placing a helipad on the hood of a parked vehicle and what implications it may have.

I have a custom helipad (24"x28" vinyl laminated fiberboard) that I place on the ground. Sometimes I find myself in a parking lot or location where it would be very convenient to place the pad on my vehicle's hood.

The pad itself is rigid so it will lay flat (and level with some shimming) but I have a couple of concerns that I would like some input on before I consider it.

STARTUP: My understanding is you do not want to power up the drone near metal objects as that can deviate the compass. I have always powered my drone on after I sit it on the pad which is always away from metal. Is it necessary to have the drone laying flat and motionless at powerup? Can I hand hold the drone away from metal and power it up and after a certain point then place the drone on the pad will be sitting on metal? Will that startup procedure effect the instruments negatively? Can I then launch from a surface with metal under the pad once the AC has been powered on and stabilized and placed on the pad?

LANDING: Knowing that the helipad is resting atop the metal hood of the vehicle, what if any effect will that have on the instruments while attempting to land? Will the AC take issue with a stationary car being under it when landing?

Thank you.

 

[Jake 61]

I tried to take off from the bonnet, (hood), of my car once. It messed with the compass in the drone and I wouldn't recommend it.

 

[old man mavic]

@CDSkeeles you would be ok to land on the hood of your car,but it would mean that you would have to either hand launch ,or find an alternative level spot some distance away ,as its highly likely that the car would give a compromised compass with all that that entails, of course in the event of a RTH you would need to stop the procedure as the drone was descending, and then manually land on the helipad on the hood of your car

 

[CDSkeeles]

I suspected as much. I believe I will keep the pad away from the vehicle. Much of what I do when I am mobile is automated so I should just continue doing it the traditional way to avoid potential interference.

 

[lilewis]

FWIW, I once tried to land on a picnic table and I got an obstacle avoidance warning and it refused to land.

 

[GrayHornet]

I frequently launch my mini 2 from my truck's tonneau cover; sunroof, hood with no issues.

 

[orionshooter]

I frequently launch my mini 2 from my truck's tonneau cover; sunroof, hood with no issues.

I also launch from my pickup’s bed cover. in fact that’s my default launch spot. My cover is made entirely of aluminum which may explain the lack of any issues.

 

[TwoSticks]

If the car is newer I bet it would not be an issue. Many current hoods are aluminum to save cost and weight which is a non ferrous metal and has no effect on a compass. If the car is older with a steel hood you might have some issues but only until you hover. I hand launch and land, you might want to learn that as well then you dont need to carry a pad around.

 

[twickers14]

Have only done it once with my Spark. Not recommended. Having said that there are a few YTubes showing drones lifting off from car tops and bonnets (hoods to you) so it does work but metal and compasses etc don’t go well together.

 

[Rquirk]

I also took off from my car roof once and it messed with the compass. I flew into a field and hovered, having taken my eyes off it while checking the RC I hadn’t noticed it was flying backwards with no input. I noticed this just before it ran backwards into a tall hedge. I stopped it within a couple of feet of the hedge and after that all seemed normal.

 

[NDWildBill]

I frequently take off from the hood of my 2018 Subaru Forester, and have not had any problems taking off or landing....ok, once I came in too low and broke a prop on a fender.

 

[itallica]

I also launch from my pickup’s bed cover. in fact that’s my default launch spot. My cover is made entirely of aluminum which may explain the lack of any issues.

my truck body is aluminum - bed cover is soft, clean, and convenient - just not too close to the cab

 

[Dbez1]

Why don’t you CAUTIOUSLY try it and see if it works for your particular vehicle? Just take it a few feet up and proceed from there.

 

[CDSkeeles]

Why don’t you CAUTIOUSLY try it and see if it works for your particular vehicle? Just take it a few feet up and proceed from there.

What is the best method of determining potential compass errors before taking off? Is the icon on the map the only indicator of which way the drone believes it is pointing?

Perhaps if I orient my pad so that it is always in a cardinally correct position, and place the drone atop it accordingly every time (ie: north facing) then I should be able expect the icon to always be pointing to the top of my screen on the map below if the drone is always sitting facing northward.

I made my own lightweight but rigid pad, complete with LED lighting. I guess a built in compass would be cool. Whether the pad compass will read correctly because of the potential interference kind of leads us back full circle lol.

Now I am itching to add a digital compass to the pad just because. I see an amazon search in my immediate future.

 

[RGS2010]

A2s owner here.

Looking to have a conversation with the group about placing a helipad on the hood of a parked vehicle and what implications it may have.

I have a custom helipad (24"x28" vinyl laminated fiberboard) that I place on the ground. Sometimes I find myself in a parking lot or location where it would be very convenient to place the pad on my vehicle's hood.

The pad itself is rigid so it will lay flat (and level with some shimming) but I have a couple of concerns that I would like some input on before I consider it.

STARTUP: My understanding is you do not want to power up the drone near metal objects as that can deviate the compass. I have always powered my drone on after I sit it on the pad which is always away from metal. Is it necessary to have the drone laying flat and motionless at powerup? Can I hand hold the drone away from metal and power it up and after a certain point then place the drone on the pad will be sitting on metal? Will that startup procedure effect the instruments negatively? Can I then launch from a surface with metal under the pad once the AC has been powered on and stabilized and placed on the pad?

LANDING: Knowing that the helipad is resting atop the metal hood of the vehicle, what if any effect will that have on the instruments while attempting to land? Will the AC take issue with a stationary car being under it when landing?

Thank you.

I took my A2S off from my car top three times yesterday (2015 Nissan Altima) and RTH came right back and landed in same spot. I don't usually do this but just on a whim yesterday. No issues. I usually take off and land in my hand. Its so convenient and no ground clutter to worry with at all.

 

[sar104]

If the car is newer I bet it would not be an issue. Many current hoods are aluminum to save cost and weight which is a non ferrous metal and has no effect on a compass. If the car is older with a steel hood you might have some issues but only until you hover. I hand launch and land, you might want to learn that as well then you dont need to carry a pad around.

This is incorrect, and bad advice. If you power up the aircraft in a location where the magnetic field is distorted then the IMU heading will be incorrectly initialized, and after takeoff the IMU and compass will then disagree. That's a recipe for uncontrolled flight, and has caused many crashes/flyaways.

Why don’t you CAUTIOUSLY try it and see if it works for your particular vehicle? Just take it a few feet up and proceed from there.

That's a bad idea too - there are much better ways to check for magnetic interference and an incorrectly initialized heading than just seeing what happens on takeoff. See below.

What is the best method of determining potential compass errors before taking off? Is the icon on the map the only indicator of which way the drone believes it is pointing?

Perhaps if I orient my pad so that it is always in a cardinally correct position, and place the drone atop it accordingly every time (ie: north facing) then I should be able expect the icon to always be pointing to the top of my screen on the map below if the drone is always sitting facing northward.

This is exactly the best method to test for a problem. Once the aircraft is initialized then check the aircraft orientation icon on the map and ensure that it is pointing in the same direction (relative to north) as the aircraft actually facing. If they agree then you are good to go. If not, then do not take off.

This problem manifests when the aircraft is near or on magnetized ferromagnetic materials. So an aluminum roof shouldn't be a problem as long as there are no steel components directly underneath it. Even a steel surface may not cause interference if it is unmagnetized, but even slight magnetization is a problem.

There is a more detailed discussion of this subject for anyone who is interested:

A short explanation of compass function, calibration and errors.

BACKGROUND The aircraft compass is often misunderstood, both in terms of function and purpose, but it is important to understand what the compass measures, why, and what happens to that information. At the most basic level the purpose of the compass is to measure the earth’s magnetic field in...

mavicpilots.com

 

[old man mavic]

@CDSkeeles i have used a method of orientating my take off pad for a few years now i like you have a home made hard pad which i have painted red with a black H on it ,i also put a small N for north on one edge
i then use a small hand held compass and align the N of the pad with the magnetic north that the compass is indicating
i do this while the compass is at chest height ,after i have set up the pad i then slowly lower the compass down till it is laying on the pad ,and watch to see if the indicator moves during the process if it does this will indicate that there is some ferrous material hidden in the ground such as rebar if this is the case then i will move the pad a few feet away and repeat the process although this takes a short time to achieve i think that the time spent doing it is worth the effort,
then when the drone is all ready to go the drone arrow will be pointing towards the small N at the edge of the attitude display and i know that i dont have a compass deviation that could cause the drone to do something unexpected after take off ,writing this down actually took longer to do and in reality the whole thing is very easy and quick

 

[dirkclod]

Why don’t you CAUTIOUSLY try it and see if it works for your particular vehicle? Just take it a few feet up and proceed from there.

Agree, not have the S2 but with my M1 and 2 my 1990 truck bed was my
pad. All steel .Never any issues. Would set it right over where the 5th wheel
ball hole was over the rear end. Now I got a 2011 ford with a aluminum body and now way. Ya don’t know till you try it.
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[MARK (LI)]

Smoking kool video @dirkclod old Mack tractor, train tracks, river, industry, crane..with Annie Lenox belting it out from behind...doesn't get much any better

 

[TwoSticks]

This is incorrect, and bad advice. If you power up the aircraft in a location where the magnetic field is distorted then the IMU heading will be incorrectly initialized, and after takeoff the IMU and compass will then disagree. That's a recipe for uncontrolled flight, and has caused many crashes/flyaways.

"So an aluminum roof shouldn't be a problem as long as there are no steel components directly underneath it."

Guess I should have said roof instead of hood.