How can I test Tach off bike?

[Anonymous]

HEy great ! Another RC Pilot!

HEy great ! Another RC Pilot!

Hey Gerry:

Sure nuff. RC airplanes and helicopters, though mostly heli's these past few years.

Earl

Nice to run into so many nice guys here and meet another modeler. I have been working as an editor for MAN magazine for 13 years! :roll: well someone has to do the dirty work right :roll: Anyway, if you'd like a free subscription let me know... this goes for anyone on the forum! just send me your mailing address and I'll set ya up for a 6 month sub or extension!
Cheers to all,
GY

PS: I even have two old RC motorcycle models!

 

[earlfor]

Re: Chopper

Re: Chopper

Hmmm Bill, I was planning on having the parachute on me.
I bet I wouldnt be able to get collision ins on the chevy though.
I wonder if I would have to pay impact fees to the DOT.
I think driving out the door at about 10,000 feet would make for a nice leisurely plummet......and yes, I insist my passengers buckle up. eh eh eh

Earl

Well Jay, for many years I have thought it would be a real hoot to
drive a 57 chevy out the back door of a C-130, but I probably will never get the opportunity.

I am curious about the minor details on this one. With or W/O parachute? Planning on landing on a large air bag? Do tell, perspirering minds want to know! Safe Riding, Bill

 

[kz]

Hi John,

I agree that a pulse generator is the best way of testing an electronic tachometer, but hoever if you have access to an oscilloscope and knowledge to use it, where is an other way.

If you connect the oscilloscope to the lead that comes from the coil you can calculate the frecency of that signal, 1/T equals frecency and multiplyed by 60 equals the revs of the engine, 4 cylinders, two coils, one spark every second turn for each cylinder, means one pulse each turn.

I tested my bouncing tach that way and could locate the problem to the three condensators (I dont know which one of them) on the ciruit board and replaced them, for a few bucks (for me kronor).

 

[Anonymous]

Re: Master of it all.

Re: Master of it all.

.....When everything is right on mine, I can put it in a hover 6 feet off the ground and put the transmitter down and walk away, and it will just sit there.

Earl

Earl:

Please consider designing some R/C- (or gyroscopically-) controlled servo's for Scotty's bike. It's a darn shame that the only time Scotty passed through "The Valley of Shame" that is his driveway, he got rained on. With a little of your engineering ingenuity, you should be able to design some device to keep Scotty vertical.

I converted a Lindberg "Fletcher Class" destroyer model to R/C (and more speed) for my son a few years ago. We used to run it on our neighborhood pond to stimulate the wildlife into some semblance of activity. I was tempted to attach a spinner and go trolling for bass but feared that it had insufficient beam for fighting the "big one" (model is 3 feet long but only 3 1/2 inch max beam).

Simon

 

[earlfor]

Re: Master of it all.

Re: Master of it all.

I have a friend that tried helicopter fishing. He tied a line with a hook and float to his landing skids and hovered over the water
30 yards from shore. well, he caught a small sea bass and you would be astounded at how much a 3 pound fish can upset the balance of a 14 pound helicopter. With a heli, you have 8 primary control movements, all of which must at all times be co ordinated and doing that coinciding to counter the movement of an unpredictable fish is just a wee tad difficult.
LEAVE this sport to professionals, DO NOT try this at home.


Earl







[quote="Simon Waters"
I converted a Lindberg "Fletcher Class" destroyer model to R/C (and more speed) for my son a few years ago. We used to run it on our neighborhood pond to stimulate the wildlife into some semblance of activity. I was tempted to attach a spinner and go trolling for bass but feared that it had insufficient beam for fighting the "big one" (model is 3 feet long but only 3 1/2 inch max beam).

Simon[/quote]

 

[Hap Call]

Hi John,

I agree that a pulse generator is the best way of testing an electronic tachometer, but hoever if you have access to an oscilloscope and knowledge to use it, where is an other way.

If you connect the oscilloscope to the lead that comes from the coil you can calculate the frecency of that signal, 1/T equals frecency and multiplyed by 60 equals the revs of the engine, 4 cylinders, two coils, one spark every second turn for each cylinder, means one pulse each turn.

I tested my bouncing tach that way and could locate the problem to the three condensators (I dont know which one of them) on the ciruit board and replaced them, for a few bucks (for me kronor).

Karl, that is an excellent idea! What was the amplitude of the pulse in volts?

Hap

 

[kz]

Hi Hap!

I am afraid I cant remember the exact voltage of the pulse, but I remeber using x10 probe so probably not more than 12V, the pulse itself is not completely clean but it is clean enough to get a good trigging and possibility to read the periodtime.

It is much easier if you have sombody else to keep the engine at a steady speed (revs) and you make all the readings on the oscilloscope.

 

[Hap Call]

Hi Hap!

I am afraid I cant remember the exact voltage of the pulse, but I remeber using x10 probe so probably not more than 12V, the pulse itself is not completely clean but it is clean enough to get a good trigging and possibility to read the periodtime.

It is much easier if you have sombody else to keep the engine at a steady speed (revs) and you make all the readings on the oscilloscope.

Hey Karl, you actually answered my real question...if a 10x probe was needed! Thanks for the great info!

Hap

 

[kz]

You are welcome Hap,

Hap, if you really are going to meassure the tacho signal I would be interssed to here what shape your signal has and if you can see any difference if you connect the probe to lead at the coil or the same lead att the tacho according to disturbance.

The reason I ask is that I belive that it is important how the lead is wired the way from the coil up to the tacho.

Just for the record, all the messasurements I am describing here are on the primary side of the coil and not at the Plug side.