'A' Test Question

[JayCee]

Can anybody tell me how you conduct a range test to satisfy the BMFA examiner on an 'Electric' plane.?

 

With IC I was told to 'Power Down' the Tx set the throttle to max (engine off obviously) have someone keep an eye on the 'Carb' while you walk away and keep walking until the 'Fail Safe' operates!

 

Not possible on a 'Leccy' not practical to have the motor running flat out while you walk off for 70 yards or so.

 

Also if you are using a BEC (No Switch) how do you isolate the plane, again to satisfy the examiner, when retrieving from the 'Strip'

 

 

JC

 

 

[Steve W-O]

You don't need to use the motor.throttle for a range test, any control will do, and I think most people check all, and for jittering.

 

You can't isolate it without a switch, but by treating it as live all the time, you are being safe.

 

You can also programme one transmitter switch to cut the throttle

 

 

I don't think waiting for the fail safe to operate is good practice, what you want to establish is controllable range, with no jittering or intermittent operation, which may be the same as when the fail safe come in, but it may not.

 

If you have no fail safe, it won't work anyway, though all ESCs do now. 

Edited By Steve W-O on 26/03/2011 16:27:25

[Andy Symons]

Errm. Range test at full throttle!!!!

 

Get someone to hold the model a few feet of the ground too, don't forget you are allowed to have a helper, if one isn't available ask the examiner.

[Allan Bennett]

With both electric and glow it's good to do part of your range check with the engine/motor running, in case metal-to-metal contact somewhere causes interference (in the case of glow), or in case the ESC and electric motor cause interference. In our club we leave the models on the ground (worst case, so far as the receiver aerial is concerned), anchored by a model restraint, and attended by a helper. If full range is achieved okay with no throttle, a quick blip of throttle will then be the final check.

 

So far as I'm concerned, 50 metres range check with the model on the ground is plenty. What I'm looking for is servos beginning to twitch -- I certainly wouldn't expect to see the fail safe (if the receiver has one) kick in.

 

As for retrieving the model, with electric models we always take the transmitter with us when we retrieve, so that we're in control of the throttle at all times until the model gets back to the pits and the battery can be disconnected.  I don't know if that's in strict accordance with BMFA rules, but it seems to me to be the only safe way to do it.

Edited By Allan Bennett on 26/03/2011 21:03:01

[Romeo Whisky]

Posted by Alan Bennet above:

As for retrieving the model, with electric models we always take the transmitter with us when we retrieve, so that we're in control of the throttle at all times until the model gets back to the pits and the battery can be disconnected. I don't know if that's in strict accordance with BMFA rules, but it seems to me to be the only safe way to do it.

 

I absolutely agree Alan - I've seen people put the TX on the ground while they retrieve, and it falls over or is blown over by the wind. I've seen the TX handed to someone else who nonchanantly chats to someone else (not paying attention) while the model is retrieved. But to me (using Spektrum) there is an even safer way. As I now only fly with Spektrum I always switch the TX off as soon as the model lands so the RX goes into fail-safe with throttle off while I retrieve. That way it is irrelevant whether I take the TX to retrieve the model or not, and everyone stays safe. I think the BMFA has a bit of catching up to do with technology.

 

I also don't see why a person who has no i/c model and no intention of ever flying i/c should have to answer questions purely relating to i/c as part of the 'A' test.

 

 

[ken anderson.]

off post---i saw a lad at our club...with his TX lying against the leading edge of his m'plex gemini...connect the battery up..the TX fell forward and the throttle went to WO...and he had some 'canny' marks on his inner thigh....as well as doing his own version of the 'highland fling'.....

 

ken anderson ne..1.

[Vecchio Austriaco]

Full throttle could lead to overheating your engine/ESC if the model is not "moving"

Also I prefer to look at jittering and especially at moving the transmitter antenna in different directions - for instance pointing at the model as this is the worst case for the transmission.

Edited By Vecchio Austriaco on 27/03/2011 09:52:49

[Tim Mackey]

FWIW

My normal routine for range testing is to have someone walk away with the model to the required distance ( 30 paces Spektrum ) and in range test mode, ensure full and smooth control of all surfaces with the model pointing toward me. I then ask the helper to rotate the model through 4 axis, so that the tail and then each wingtip faces me in turn. I then repeat the test with the motor running. Short, static, throttle operation like this should do no harm to the powertrain.

[Steve W-O]

Posted by Tim Mackey - Administrator on 27/03/2011 10:42:56:

FWIW

My normal routine for range testing is to have someone walk away with the model to the required distance ( 30 paces Spektrum ) and in range test mode, ensure full and smooth control of all surfaces with the model pointing toward me. I then ask the helper to rotate the model through 4 axis, so that the tail and then each wingtip faces me in turn. I then repeat the test with the motor running. Short, static, throttle operation like this should do no harm to the powertrain.

 

 

 

 

 

..................I then ask the helper to rotate the model through 4 axis,

Very important, especially so with single receiver/antenna 2.4 equipment.

[Hogster]

I thought a range check and fail safe operation were separate tests. I was taught to range check with Tx in power down mode at 30 paces. Fail safe was checked by simply switching the Tx of whilst model restrained. The engine didn`t have to be at full throttle. The simple requirement was for the engine to stop.