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Can we get synthetic airspeed on the OSD without using pitot tube on a Heli?

HI all,
Can we get synthetic airspeed on the OSD (like we can have on a arduplane)without using pitot tube on a Heli same like we have on a arduplane?Thanks.

Anyone please? Thanks.

What do you plan to use it for? Do you even know how airspeed is estimated when using this synthetic airspeed?

Bill,i always appreciate your help and time you give it to this forum but this time i felt this little rude and i don’t know why you got upset?No i don’t know how synthetic airspeed is calculated.I am just a normal hobbyist who uses arducopter.I am not a programmer and don’t have programming background.

I was planning to use it on my helicopter while flying in windy conditions.I think it will be helpful to have an idea of windspeed before letting your heli for a long range mission and running out of battery.In that way one can be aware of not going too far if there is a headwind while coming back to home.That was my plan.At first i was trying to install pitot tube but then i thought it would be hard to protect the pitot tube orfice from prop-wash and that’s why i was thinking of synthetic airspeed.Like you make a one circle to get an idea of wind direction and speed.

I am sorry if my question upset you but my intentions were not wrong.Hope you understand.

@ninja_zx11 I’m sorry that I came across as rude. I can be a bit blunt sometimes. I was just interested in why you thought it was necessary. Personally, I think heli’s should be flying on airspeed for certain applications.

Well if you got the airspeed tube mounted, it wouldn’t have work anyway as copter is not set up for airspeed sensors. I tried but the Lead devs placed a lot of additional coding to get it implemented. So I moved on as I have bigger things to tackle with tradheli.

I once had it working on a personal branch. It was great! Like you said the rotor downwash did affect it but once you got above 8-10 m/s, it cleaned up pretty nicely.

As for the synthetic airspeed, I was doing a little digging into the code. It is buried in there and not really easy to see how it’s done. I was just curious. It is in a common library and should be usable from copter but like all things, requires time to put it in.

Anyone else with the skills and desire to implement this and while you are at it the airspeed sensor, that would be a great addition for heli users.

@ninja_zx11 again sorry for the blunt response.

No worries my friend!! Its all good.and i am sorry too if i overreacted to your question.

Your’s and Chris’s wealth of knowledge is keeping this forum alive!!

I wish i know how to read the code:) Yes like you said,having a synthetic airspeed would be really helpful in our heli application where prop wash is a problem.

Just curious how and where is pitot tube mounted on a real helicopter?

Synthetic airspeed using the fly forward AHRS assumption, that is that we are always pointing the straight into the apparent wind. This means that we can estimate the air speed from the crab angle and GPS speed. There are some clever filter and stuff to make that work better.

Because copters do not always point into the apparent wind like planes do the same method does not work.

To just add a airspeed sensor to only report to the pilot is probably just a matter of exposing the params, the library is already included in copter as it is needed by the AHRS.

It was mounted on the nose, as far out as I could get it.


You can see it at the end of the nose.

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it got a little more involved than that. Here is the pull request that chobitsfan and I were working on. Like I said, it was getting pretty involved. They wanted me to make changes that extended into Plane. More effort that I had time for.

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