engine timer legal?

In another thread it was mentioned that a mechanical engine shut off timer is not legal in FAI. What about AMA/PAMPA in the US?

>In another thread it was mentioned that a mechanical engine
>shut off timer is not legal in FAI. What about AMA/PAMPA in
>the US?

AMA/PAMPA, at present, yes, but there are rule proposal changes that could affect this in the future. FAI does not allow any shut-offs and there are no proposed changes that would.

>>In another thread it was mentioned that a mechanical engine
>>shut off timer is not legal in FAI. What about AMA/PAMPA in
>>the US?
>
>AMA/PAMPA, at present, yes, but there are rule proposal
>changes that could affect this in the future. FAI does not
>allow any shut-offs and there are no proposed changes that
>would.

I don't see anything in the AMA proposals that would make it illegal. Moreover, I beleive that the proposed FAI rules would allow a shutoff.

It's for sure not legal in FAI right now.

I was thinking of the infrared controls or the like, but you are right, Brett, I don't think there is anything proposed to affect a timer itself. To me the ideal shut off would be the Z-tron, not used for speed control but simply for motor shut-off. Two laps after the pattern and you could kill the engine. Everything related to flight would still be controlled through the lines.

It would speed up contests, but the purists would say "no more overruns" (true) and it may give an unfair advantage in being able to shut off the engine anywhere in the circle in relation to wind or judges position. (Windy's landings with the Z-tron speed control were impressive in that he could bring it down and place it right in front of the judges.)

Ron B.
F4Fguy

Leonard:
I don't know how much flying you've done with throttled engines in U.C.,but in my experience it requires another whole skill set.It's not easier to land,its more difficult(to do well).A properly done approach and landing requires you to plan your approach several laps ahead,reduce power slowly and steadily to the final flare,then cut power to idle,touch down,roll out,stop,and cut engine.If it's not done in this manner,it looks terrible,worse than a mediocre conventional P.A.rule book landing.I don't always agree with Windy,but in this case I believe he's being way underestimated.Not only should the proposed rule change NOT go through,but more should be done to encourage this kind of innovation and application of available technology.
The status quo may be comfortable,but it also is stagnating.

>I was thinking of the infrared controls or the like, but you
>are right, Brett, I don't think there is anything proposed
>to affect a timer itself. To me the ideal shut off would be
>the Z-tron, not used for speed control but simply for motor
>shut-off. Two laps after the pattern and you could kill the
>engine. Everything related to flight would still be
>controlled through the lines.
>
>It would speed up contests, but the purists would say "no
>more overruns" (true) and it may give an unfair advantage in
>being able to shut off the engine anywhere in the circle in
>relation to wind or judges position. (Windy's landings with
>the Z-tron speed control were impressive in that he could
>bring it down and place it right in front of the judges.)

Can't folks just take a couple of flights to find the right amount of fuel needed?

If you are living as a BOMER (the hard way) why are you advising others to go the "easy way" (Paul said something like that to Peter, in Galatians)?

One should know his engine, its fuel consumtion, how the nitro and oil percentages, altitide, temperature, and other factors affect the amount needed to make a 6 minute flight.

Using a shutoff device would (even if all competitors had it) void the "advantage" and the rewards due to the guys that take the trouble to find out the amount of fuel needed, just like abolishing the BOM would rob the builders from the prize they deswerve for the effort of building their ship.

In Christ,

Ion (do I sound hardliner enough?) Brazil

In fact, the FAI rule is totally unenforceable because the models are not scrutineered. I have flown in local FAI events with a shut-off to prove the point and then disqualified myself from the event.

>In fact, the FAI rule is totally unenforceable because the
>models are not scrutineered. I have flown in local FAI
>events with a shut-off to prove the point and then
>disqualified myself from the event.

That doesn't mean it's unenforcable, just that it's not enforced. Most modeling rules are based on the basic honesty of the participants, not strict enforcement. I don't think anyone really wants Forumla 1 racing style impounds and inspections, and I don't think it's necessary.

I've just never seen the problem with the idea of a mechanical shutoff. I mean, what possible argument could there be against it? It just seems to be a silly tangential non-problem which didn't need a solution.

I fully support the proposed FAI rules about eliminating IR/RF controls. The way WIndy used the Ztron seems more-or-less OK to me, but you could use remote control to do a whole lot more in a lot of different events. At some point, you have to define what it means to have a control-line model.

Dan Banjock and I had this argument (gentlemen's style, not shouting-match style) at the NATs. He said "All I want to do is shut off the engine" and I said, "Yeah, that's all you want to do - that's not all anyone else wants to do". It's entirely feasible to run auto-racing style backrooms with people in the pits setting, say, compression and needle on FAI Team racers in flight based on telemetry. I doubt that it would be practical right now due to the weight of the equipment, but that's a workable problem. I don't think that fits my vision of the way things should be. Of course, that' just me.

An important element is to draw the line somehow between potentially "active" trim systems (like Igor's rate control gyro/servo system) and something like an autopilot. That's the reasoning behind the "elevation controls must be mechanical" part of the proposal.

The possible argument against it is that it may be considered an advantage when avoiding overruns..

As a practical matter, I'm all for shutoffs.

But traditionally, part of flying a stunt ship was to get the engine to run for the correct amount of time all by itself.

Like the BOM, I'm inclined to want to keep it as a rule.

[photo not recovered: 3e69bb3870f12ad5.jpg]

"The British have a reputation for keeping calm even when there is no crisis."

In a previous discussion in a different era and a different forum, when the FAI defined the ban on shutoffs, things got a bit silly...

One flier, maybe Igor can refresh our memory?, used a tank with a vertical front-to-back baffle that only refilled the pickup tube area while inverted or doing negative g. ---Banned.

Conceivably, and I think also discussed, a rectangular tank (no wedge feeding the pickup) which CAN be used late in the run to shut it off by flyuing level at a high line angle would also have been ---Banned.

A prominent (?) Russian flier used a spring-loaded bellcrank moount, which could trip a fuel shutoff by applying an extreme, sudden pull from the handle --- Banned.

The idea that all controls should reach the model via the flying lines seems to have been expanded to make it mean ONLY mechanical control of the flying surfaces.

For AMA guys, remember that the FAI time limit is SEVEN minutes from start signal to end of landing roll. Much ingenuity went into getting a sure, quick start and a dependable engine stop within that time.

This is almost as much fun as discussing BOM...

>The idea that all controls should reach the model via the
>flying lines seems to have been expanded to make it mean
>ONLY mechanical control of the flying surfaces.

See above

I might add that the AMA CLG-01 proposal was changed after publication to be more like the FAI proposal. Not necessarily for "convergence' purposes, either. I was going to counter-propose the original because it was too vague.

Actual wording of FAI rules is not clear about shut offs. It says that controlling is disallowed, but does not define what that “controlling” is. We use timer to shut off and we also control the power output by an automatic device – this is for sure. The tank with measured fuel and pipe is clear example of such devices. The new rule proposal should solve that problem. It has to be clear as much as possible, and I think it is.

If the “controlling” is only action of pilot, than all automatic devices should be considered legal, including tank with measured volume, and also electronic timer a centrifugal regulator. Only shut off by lines or another device controlled by pilot should be considered illegal. That looks logical, but what is the loop on end of flight shutting off the engine? Isn’t it illegal? All such crazy questions were reason why the actual wording is very clear – allows all beside high frequency.

Actual draft is available here:

http://www.slovanet.sk/orsia/rules.pdf

Engine shut-offs are a great idea. They should be set up like on team racers, where full down elevator shuts off the engine.

After looking over the proposal from Igor Burger's reply, I would say it will be legal and a good idea. The best way to avoid that embarrasing stare during practice when your just doing laps after the pattern. I guess that one was too lean!!
Andrew Raney
Dallas

I was thinking about a timer for an electric stunter. It looks to me like there are good (but expensive) motors available. One difficulty is the battery. If you size the battery to quit at the right time it is running out of power just when you need it most, in the four leaf clover. If you size the battery to provide sufficient power at the end of the sequence, it runs too long. A shutoff time would address this one issue... Battery weight is still an issue but I guess you can throw money at that one too...

>I was thinking about a timer for an electric stunter. It
>looks to me like there are good (but expensive) motors
>available. One difficulty is the battery. If you size the
>battery to quit at the right time it is running out of power
>just when you need it most, in the four leaf clover. If you
>size the battery to provide sufficient power at the end of
>the sequence, it runs too long. A shutoff time would address
>this one issue... Battery weight is still an issue but I
>guess you can throw money at that one too...

Not any reasonable amount of money. There are battery types with more capacity for a given weight than modelers are currently using, but they are not sized for models, and even if you could get one, it would be very prohibitively expensive.

Otherwise, to get 6 1/2 minutes, with reasonably strong power, you need batteries that are maybe 50% bigger and heavier - and there goes the performance for the whole flight.

I'm sure that if it was simply a matter of adding batteries and then having a shut-off (actually, I would probably use motor voltage not a timer) then I'm sure the experiementers thought of it.

A regulator would address the problem as well, but even a reasonably sophisticated regulator has some loss associated with it.

A C/L flight shut-off seems like a good idea. The suggestions so far have been to incorporate some sort of elapsed timer to shut off after a pre-determined time. This seems about useless. One can measure fuel and get pretty close, especially if a test flight is taken to zero in on fuel consumption for any particular day.

What is really needed is a shut-off-on-demand. This would take care of attempts and the variations in fuel consumption based on needle settings, weather, humidity, and etc.

Back in the '40s, we ran spark engines in C/L with a handle containing a couple of "C" batteries. Pushing the button on the handle sent 3 volts through the insulated lines to a relay in the model. This relay would break the spark ignition circuit and terminate the flight to save an over-lean run, or a bad spark plug/battery. We insulated our own lines with G.E. "Glyptal" varnish, which added some line drag, and had to be replenished from time to time.

I don't see any argument against this type of control, because it would be via the two lines, and not any kind of IR or RF link.

To do this nowadays would requrie an electro-mechanical fuel line pinch-off gadget. Another problem with this is that we don't use insulated lines these days. So, after the pattern, are the lines still twisted? (I haven't gone through all the loops to determine if the lines are twisted or separate). If still separated, the lines could take a shot of current to an electro-mechanical shut-off in the plane. Of course, this wouldn't work at all halfway through the pattern when the lines are twisted.