Does any body know source of small size electronic timer (for one command for engine shut of system)need for gas power. What our experienced electric power guys use? Are those timers convertible for gas? I can obtain one of the best timers from Free Flight guys, but those are several commands I will not use, and little big than I wish.
Electronic timer
Stuka Stunt Main Forum · 12 of 12 known posts recovered
I''m not sure if this is what you mean--they are the timers I use for electric CL. You will still a battery (~$15) to run the timer and a small micro-servo (~$15) to operate a throttle or some type of fuel pinch-off.
http://bsdmicrorc.com/products.cfm?catID=10006
Will Hubin is also producing timers--I don't have a link to his.
http://bsdmicrorc.com/products.cfm?catID=10006
Will Hubin is also producing timers--I don't have a link to his.
Alan
>Does any body know source of small size electronic timer
>(for one command for engine shut of system)need for gas power.
>What our experienced electric power guys use? Are those timers
>convertible for gas? I can obtain one of the best timers from
>Free Flight guys, but those are several commands I will not
>use, and little big than I wish.
I posted this in response to a similar question on SH. The problem is much more complex than it first appears.
The Electric setup:
1. When you "start" the motor you are at the same time starting the timer countdown. The two are in sync and will not result in a flight running short or long. It will run exactly to the preset duration.
2. The mechanism to actually shut the motor off is just some logic in the chip. Logic weighs very little. No other physical apparatus is required. The power for this comes from the flight battery and so there is no additional weight penalty incurred.
The IC setup:
1. Assuming you have implemented a timer, you would have to decide whether to manually start the timer before flipping the prop (and taking a chance that the engine did not fire immediately with a resulting shortened run) or manually initiating the timer after the engine had started (with the possibility that the time taken since signaling the timekeeper is longer than what is required to shut off and land under the time limit)
2. You will need to determine an effective means of stopping the engine. A partially shut off engine will run lean, cook the engine and put you over the time limit. If you are racing this might not seem like much of a risk. In stunt a good motor is a pretty valuable commodity.
3. You will need some physical means to make the engine shut off. Let's assume you will pinch the fuel line. You will need a battery, a servo, a timer/device to control the servo, a method of setting/initiating the timer, access to all of the components (the battery will need to be removeable), access to the fuel line from the servo and a device to hold the fuel line while you are pinching it. This will weigh a fair bit and will need to be located up close to the nose of the plane. (C of G issues)
Alternative IC Setup:
Meter the correct amount of fuel. Simple, reliable and very light.
Kim
>(for one command for engine shut of system)need for gas power.
>What our experienced electric power guys use? Are those timers
>convertible for gas? I can obtain one of the best timers from
>Free Flight guys, but those are several commands I will not
>use, and little big than I wish.
I posted this in response to a similar question on SH. The problem is much more complex than it first appears.
The Electric setup:
1. When you "start" the motor you are at the same time starting the timer countdown. The two are in sync and will not result in a flight running short or long. It will run exactly to the preset duration.
2. The mechanism to actually shut the motor off is just some logic in the chip. Logic weighs very little. No other physical apparatus is required. The power for this comes from the flight battery and so there is no additional weight penalty incurred.
The IC setup:
1. Assuming you have implemented a timer, you would have to decide whether to manually start the timer before flipping the prop (and taking a chance that the engine did not fire immediately with a resulting shortened run) or manually initiating the timer after the engine had started (with the possibility that the time taken since signaling the timekeeper is longer than what is required to shut off and land under the time limit)
2. You will need to determine an effective means of stopping the engine. A partially shut off engine will run lean, cook the engine and put you over the time limit. If you are racing this might not seem like much of a risk. In stunt a good motor is a pretty valuable commodity.
3. You will need some physical means to make the engine shut off. Let's assume you will pinch the fuel line. You will need a battery, a servo, a timer/device to control the servo, a method of setting/initiating the timer, access to all of the components (the battery will need to be removeable), access to the fuel line from the servo and a device to hold the fuel line while you are pinching it. This will weigh a fair bit and will need to be located up close to the nose of the plane. (C of G issues)
Alternative IC Setup:
Meter the correct amount of fuel. Simple, reliable and very light.
Kim
Thank you for reply.I would agree with you, that control amount of fuel would be the best, light weight and most cheapest way to control flight time. That what i have been doing all my life. But now there is opportunity to install timer, because electric guys use it. On the contest side , when you do first official flight in 8:30 in the morning when it is quiet and some times the best weather condition you would wish. And second flight close to 2:30 PM, when temperature has reached 95F and wind blowing 15M/H. This required to change some settings. Like different prop, which may forced engine to eat more or less fuel, some times it require different fuel mixture. Of course i have chart in my pit box RPM for each prop and approximate amount of fuel. Why a call it approximate - because has ben written on practice field when it was different altitude and lap speed could be different,and weather was different.Of course pre flight before morning official flight and after noon flight could fix most of this issues. But the problem is, not always you have that opportunity - practice circle has been taking by some body else, or contest side do not have enough space for practice circle. Than I came to conclusion- why do not try the timer? It may be better than loose flight for 8 second overrun. I understand all complexity of use combination electronic an mechanical performance.I'm not to scare of it because I have no doubt it worse it.
Wasn't able to put everything in because I had to be out at the airport at 10AM this morning to prepare for the contest on Sunday.
As Kim says, there are issues using a timer with a glow engine. Here's what I was thinking.
Lets start with a JMP-2 timer, since I think that more-or-less could fit the bill. It has several features which are important.
1) Has a "Start Button". This start button also can terminate timer functions, as I will point out.
2) It has a delay time of up to 100s which also has a throttle setting associated with it. This is where you would try to start the engine.
3) There are two other times/throttle periods.
3a)Total Flight time--this is the time after the delay time in 2), after which the throttle is set to zero.
3b) First flight time. This is a segment of 3a, which starts immediately after the delay stops. During this time you have a throttle setting.
3c) After 3b is over, but before 3a (total time) is finished, the throttle will ramp up (or down) linearly to a final value at the end of the period. This is mainly used in Electric to juice up the throttle as the battery voltage dies off during the flight. In glow you could use it to increase throttle. If the throttle is set the same as 3b, then throttle stays the same.
Ok here is how I would do it in competition.
1) signal judges, push "Start Button". Throttle goes the starting position--wherever you want it if you are using an RC carb. Start cranking the prop. You have up to 100 s (or whatever you programmed) to get the engine to start. If it doesn't start, wave off the attempt.
2) If it does start, you can then push the start button again. This will stop the delay period instantly. At this point the Total flight time starts and the throttle moves to the First Flight programmed value. Now you could tweak the needle if you want--as long as you programmed in a long enough (~5min30s to 6 min should be enough depending on your lap speed). If something is still wrong and you want to wave off the flight, push the start button again and the timer terminates and the throttle goes to "0".
3) If ok, saunter confidently out the the center to pick up your handle, confident that overruns are only a dim memory of the past!
4) When the total time times out, the throttle is set to "0" which I assume you have set to stop the engine.
This obviously was a servo setup. I think it would work without too many hassles. Whether it is worth it or not would be up to you.
As Kim says, there are issues using a timer with a glow engine. Here's what I was thinking.
Lets start with a JMP-2 timer, since I think that more-or-less could fit the bill. It has several features which are important.
1) Has a "Start Button". This start button also can terminate timer functions, as I will point out.
2) It has a delay time of up to 100s which also has a throttle setting associated with it. This is where you would try to start the engine.
3) There are two other times/throttle periods.
3a)Total Flight time--this is the time after the delay time in 2), after which the throttle is set to zero.
3b) First flight time. This is a segment of 3a, which starts immediately after the delay stops. During this time you have a throttle setting.
3c) After 3b is over, but before 3a (total time) is finished, the throttle will ramp up (or down) linearly to a final value at the end of the period. This is mainly used in Electric to juice up the throttle as the battery voltage dies off during the flight. In glow you could use it to increase throttle. If the throttle is set the same as 3b, then throttle stays the same.
Ok here is how I would do it in competition.
1) signal judges, push "Start Button". Throttle goes the starting position--wherever you want it if you are using an RC carb. Start cranking the prop. You have up to 100 s (or whatever you programmed) to get the engine to start. If it doesn't start, wave off the attempt.
2) If it does start, you can then push the start button again. This will stop the delay period instantly. At this point the Total flight time starts and the throttle moves to the First Flight programmed value. Now you could tweak the needle if you want--as long as you programmed in a long enough (~5min30s to 6 min should be enough depending on your lap speed). If something is still wrong and you want to wave off the flight, push the start button again and the timer terminates and the throttle goes to "0".
3) If ok, saunter confidently out the the center to pick up your handle, confident that overruns are only a dim memory of the past!
4) When the total time times out, the throttle is set to "0" which I assume you have set to stop the engine.
This obviously was a servo setup. I think it would work without too many hassles. Whether it is worth it or not would be up to you.
Alan
Thank you for your valuable inputs! How about this: You signal to judges, same time push the button of your stop watch. Your official flight time has began, than crank the engine. When it start push the start button of your timer. Your pattern time is 6:40 Pure timer time should be 7 min around You have all most 1 spare minute of 8 min flight. So - 15 sec to go take handle and obtain loop around your wrist say 10 sec more.It is 30 sec. total. If your engine will not start within 30 sec. You know it will not enough time to left for flight. Tis is the time to make decision about attempt.
Even simpler.
Just signal the judges and push the timer button/switch to start it and also start your watch at the same time.
Then start flipping.
The timer will stop your motor in time to land before the end of your 7 minutes (assuming you get it going) and you can decide at say 30 seconds if you are going to call an attempt.
No math to do in your head this way.
The entire timer could likely be built into a servo by replacing the existing circuit board, so all you would need would be a single Lipo cell, the timer/servo and an on/off switch.
Pat MacKenzie
Just signal the judges and push the timer button/switch to start it and also start your watch at the same time.
Then start flipping.
The timer will stop your motor in time to land before the end of your 7 minutes (assuming you get it going) and you can decide at say 30 seconds if you are going to call an attempt.
No math to do in your head this way.
The entire timer could likely be built into a servo by replacing the existing circuit board, so all you would need would be a single Lipo cell, the timer/servo and an on/off switch.
Pat MacKenzie
Well what I like about my method is that I can set a start position. That is a difficulty if the starter isn't armed. How do you set the servo arm (or throttle)---especially if it is a full fuse plane and all this is buried inside (except for the push button)?
In RC I never start the engine at full throttle, but usually about 1/2 throttle. It just feels safer. This is still less than CL usually.
And if it takes you over 100s (the maximum time allowed in the JMP-2 ) for this period) to start, you had better wave off anyway. In my experience, I almost always get a start in a flip or too with my glow engines (with electric--always even without a flip!!). You don't want to get too fancy with other watches etc. Right now when I push my start button, I do enable a countdown clock-timer (that "talks" the remaining time to me on the minute, but sometimes I do forget to start the clock. Competition does cause you to do some dumb things at times (maybe this is one of them!
)
And this is available today, no other work is necessary. The weight of the timer is a few grams, the servo 8g, and a small nicad (270mAHr, 55g or 1.9oz) or 350mAHr NiMH pack is 35g (1.9oz). A single Lipo (220mAHr--5.6g) would be a lot lighter and probably work, but you would need a Lipo charger rather than a typical RC Nicad charger. With a lipo the total added weight would be a little over 1/2oz (not counting the extra weight of the rc carb of course).
In RC I never start the engine at full throttle, but usually about 1/2 throttle. It just feels safer. This is still less than CL usually.
And if it takes you over 100s (the maximum time allowed in the JMP-2 ) for this period) to start, you had better wave off anyway. In my experience, I almost always get a start in a flip or too with my glow engines (with electric--always even without a flip!!). You don't want to get too fancy with other watches etc. Right now when I push my start button, I do enable a countdown clock-timer (that "talks" the remaining time to me on the minute, but sometimes I do forget to start the clock. Competition does cause you to do some dumb things at times (maybe this is one of them!
)And this is available today, no other work is necessary. The weight of the timer is a few grams, the servo 8g, and a small nicad (270mAHr, 55g or 1.9oz) or 350mAHr NiMH pack is 35g (1.9oz). A single Lipo (220mAHr--5.6g) would be a lot lighter and probably work, but you would need a Lipo charger rather than a typical RC Nicad charger. With a lipo the total added weight would be a little over 1/2oz (not counting the extra weight of the rc carb of course).
Alan
That weight is not acceptable! It perfect for training purposes. For serious stunt ship need some think more light. I keep researching.If I will find, let you know.
I'm expecting a "smiley" on this response!
Alan
Hi,
this is maybe some thoughts not originally belonging to this specific subject....
...however, there is one gadget that really would help to save engines, and that should be some radiocontrolled device that stopps the engine immediatly.
The background to my thoughts are: When making the the first flights with a new stunter and a new / unfamiliar engine, it happens from time to another that the engine suddenly goes in to a very lean running mode, there are also other situations like problems with the handle/lines, or people/dogs/children entering the ring. In theese cases it is really nerve killing to fly until the tank is empty.
I am quite sure that a simple device that could easily stop the engine from a remote source would be popular.
In my point of view it would be the best solution to block the air intake in some way.
Cheers! // Ingvar, living in the rainy city of Boraas in Sweden
this is maybe some thoughts not originally belonging to this specific subject....
...however, there is one gadget that really would help to save engines, and that should be some radiocontrolled device that stopps the engine immediatly.
The background to my thoughts are: When making the the first flights with a new stunter and a new / unfamiliar engine, it happens from time to another that the engine suddenly goes in to a very lean running mode, there are also other situations like problems with the handle/lines, or people/dogs/children entering the ring. In theese cases it is really nerve killing to fly until the tank is empty.
I am quite sure that a simple device that could easily stop the engine from a remote source would be popular.
In my point of view it would be the best solution to block the air intake in some way.
Cheers! // Ingvar, living in the rainy city of Boraas in Sweden