X-2 Rocket Glider

[EricClark]

Well, I have successfully built and flown a scratchbuilt rocket powered glider that drops off or a motherplane. Link. (http://www.rcgroups.com/forums/showthread.php?t=803111) Now, I am wondering if I could get some help. See, this is my final project for a physics class and I need to explain the physics involved with the flight of this rocket powered aircraft. However, I have no way of getting any DATA except for very crude methods that I do not wish to use (like people with stopwatches and measuring out distances, etc....) Does anyone know where to buy light onboard electronics (reasonably priced) or other methods of which I could obtain data to explain the physics of the aircraft?

(Or suggestions on what to explain? There's a lot. :D )

Eric

[Cory]

Are there any Dynamic Soaring pilots in your area with a radar gun?

[EricClark]

Not really. Not here in the city but maybe somewhere in the state. However, I dont know many other fliers in the state other than the local ones. :( Do you know where to buy radar guns and/or about how much they cost?

Eric

[HugePanic]

you could make a movie (or a series of photos) of the plane(s).

you could make distance and angle marks on the ground and then calculate speed and position of the aircraft.

if you can make two or more movies (from differen locations) you can have the 3d flightpath of the planes.

(At WWII the Germans used Theodolites to make their flight path measurements, that is the same method)

this will coust you nothing, and brings a lot of work... :o

[Cory]

Not really. Not here in the city but maybe somewhere in the state. However, I dont know many other fliers in the state other than the local ones. :( Do you know where to buy radar guns and/or about how much they cost?

Eric

I'm not really sure on the cost, but I think five or six hundred on the low end. Ask in the DS forum if there is anyone with a gun near you.

[EricClark]

Ahh, ouch, thats expensive. :eek: I'll look into it. Thanks for the info.

you could make a movie (or a series of photos) of the plane(s).

you could make distance and angle marks on the ground and then calculate speed and position of the aircraft.

if you can make two or more movies (from differen locations) you can have the 3d flightpath of the planes.

(At WWII the Germans used Theodolites to make their flight path measurements, that is the same method)

this will coust you nothing, and brings a lot of work... :o

Nice! Thanks, I have never heard of this before but thats really interesting. I am not worried about work as much as effectiveness and cost. I'm totally going to research that. Thanks!!

Eric

[raptor22]

If you can run it fairly close to a camera or other microphone you can use doppler measurements. The software is free and straightforward to use.

--Alex

[Brandano]

If you can run it fairly close to a camera or other microphone you can use doppler measurements. The software is free and straightforward to use.

--Alex
hard to do that with a rocket glider... for a Doppler measurement you need a motor, running at fairly constant RPM. maybe if it's possible to fit the glider with a loud buzzer it might be a viable setup. if it's loud enough it might be possible to set up a few microphones on the field and trace the 3D path from the recorded sound, assuming accurate timing on the recordings.

[vintage1]

To do it by geometry, you need to know how far away the model is, and what angle it moved.


If you have a video camera and a pair of sticks, that will give you if you set up the camera behind them some distance away, a means to time the model in terms of frames, to cover that angle covered by the distance between the sticks.

To convert that to velocity, you need to know how far away the model was.

Since you know how far apart the sticks were, and how LONG the model is, you simply extract all the frames from the clip, and put each one up in a drawing program, measure the pixel size of the model and the pixel size between the sticks, to get the distance with a bit of maths. I.e, if the model averages out at one tenth of the distance between the sticks, and the model is a foot long and the sticks are ten foot apart its actually at the sticks! If its 100th of the apparent size if the distance between the sticks its ten times as far from the sticks as the sticks are from the camera, so its actually eleven times further from the CAMERA than the sticks.

This is a really good 'school project' way of doing things: shows lots of ingenuity, use of statistical averaging, and applications of basic trigonometry.

[Neil Walker]

Fancy (GPS, accelerometer, airspeed, etc), but expensive and maybe a bit bulky for your application:

http://www.eagletreesystems.com/Plane/plane.html

Simpler (just top speed) and cheap & small:

http://www.wingedshadow.com/howfast.html

There are several threads in the High Performance section of people's experiences with the "How Fast" product, and there are people all over the boards who have used the Eagle Tree products.

[HugePanic]

here is something for you.

this is more or less a 3d flight path of a remote controlled bomb in wwII.

There is also some explanation given, but i doubt you can read it! ;)

if you have specific questions, then just ask.

[Brandano]

I still think that a beeper and several microphones could turn out interesting data. Naturally you'd need a common source to sync them, like a fixed beeper on the ground. And you'd need to correct for doppler shift. AND for wind direction. However, using timing differences you could triangulate the position in a 3D space pretty much as a GPS does. The more microphones, the more precise the positioning

[EricClark]

Wow, thanks for all the info and ideas guys! I really appreciate it!

Eric

[mnowell129]

The eagle tree stuff works great. I have the voltage/current model. But they have airspeed etc. It just downloads to the PC and makes nice plots.

[EricClark]

It does look nice but... the price. :eek: I just cant afford that right now.

Eric

[EricClark]

Nice bomb diagram HugePanic. That is one of the neatest things I have seen on this forum!

Eric