Hi Gang,

We have talked a lot about the IDEAL ECL system, one that would INCREASE RPM when line tension decreases. The ideal would allow us to fly very slow in level flight, and on the down lines. This would save mAh and allow lighter batteries. This would also REALLY tic off our wet fellow flyers. 

It looks like Wolfgang has one that is working, AND it looks like it is for sale. I just ordered one. I will keep you posted on their availability, etc. The report below guesses the price will be approx. 50 Euros.

Press the "HIT" button in the report to see a short video of Wolfgang demoing his system:

http://www.clacro.de/Seite_timer.htm

Regards, 

I have been thinking a lot about what you would need to boost the power at just the right point and for just the right length of time. It is actually quite tricky. That's why I have been putting more effort into the "passive" approach which is going for the propeller which increases thrust fastest as airspeed drops. Of course this approach isn't the end-all either.

As I mentioned on some other thread, it really makes one appreciate the 50+ year old technology of a Fox35!

Hi Guys,

Linheart,

Thanks for your comments. I always enjoy hearing from you. We all owe you a big Thank You for turning us on to the benefits of the APC-E 12x6 props, they have made a big improvement in our E power systems. My P-40 went from a good flyng ECL plane to a GREAT flying ECL plane after you told me about your prop! :-)

I thought the same as you did after seeing Wolfgang's video. Then, after reading the text again, I interpreted his hand movements as "accelerating" and "decelerating" the card to simulate different G loads. This change in G loads changed the RPM in the motor. (I could be wrong, it has happened before ;-) He is away on business for several days but I hope to get a clarification from him next week. I also hope to get some feedback from the test flights he, and others have done.

Igor,

You and Linheart have a good point about the possible speed up on the down maneuvers if they have lower line tension. This is opposite from the ideal. Gravity is bringing us down fast enough, we sure don't want to help by increasing our RPM! ;-)

I don't think we are looking for flying slow on the down line, just decreasing our RPM enough to compinsate for the normal acceleration from gravity. If we can keep the down lines at the same speed as our slower up lines, then the pattern should look more balanced, and give it a smoothness that will look more pleasing to the judges, and it will make the down lines a little less "stressful" for the pilot at the 5' alt. ;-)

Your right, our gov mode helps our ECL planes address these problems and almost solves them. I agree about not needing additional speed overhead, as long as we are in near perfect CLPA conditions with winds below 7K and little or no turbulence up high. IMHO: When the wind picks up, and/or there is turbulence up high from trees, etc. then extra speed is important overhead. In these conditions I just turn up my power on my JMP timer and this helps a lot. But it also increases my speed everywhere, which is not ideal.

Alan,

My guess is that you hit the nail on the head. All this "tweeking" to get the right speed and the right line tension at just the right time is very tricky, maybe even difficult? I like your passive idea. With our E systems we do have a lot of room to play with torque at changing speeds/loads. You, and others, have always said there is still a lot of ECL gains to be made in playing with props. Please keep us posted with your results.

I totally agree, the early wet engines 4/2 was a good idea, and when everything goes perfectly it worked very well. One of our goals in ECL is to match this 4/2, and maybe exceed it. (On a personal note: I am very hesitant to give any credit for anything to a criminal predator like D Fox.)

I THINK THIS QUEST IS WORTH THE EFORT:

If we stopped development where we are now, with our reliable, repeatable, turnkey, powerful, governor controlled systems, I would still be a very happy CLPA flyer! :-) I think we are = to or better than the best wet systems out there (especially when you consider the importance of reliability and repeatability).

BUT, IMHO: The quest for the holy grail of having the really smooth, even paced, slow motion, in almost any WX, performance like we have in IMAC and pattern RC flying may be worth some extra effort. To do this without a pilot throttle control is a real tech challenge. With people like you three, Dean, Wolfgang, Kim, Mike, Will, and many others working on it, I'm sure it will be solved. :-)

My ideal would be a plane flying slowly, 6+ sec laps, then pulls uphill with no problems, slow down lines, with full control (line tension) at all times, in any WX. I think we are getting closer with our ECL systems (and the wet piped systems). But the goal is still out there. 

OUTSIDE THE BOX?

This may be a little outside the box, but we may want to consider mounting a small E-Fan motor near the outside wingtip, perpendicular to the flight path. Using Wolfgangs G-Sensor system would allow us to send a variable amount of power to this Fan unit to maintain line tension without the speed up on the down line problem pointed out by Igor and Linheart. The new E-Fan units are getting very efficient and are relatively light. (we need tip wt anyway ;-).  I hope one of our dedicated experts out there tries this someday.

Thanks again for all your comments. It will be interesting to see how this new product performs in the real world.

Regards, 

Hi Igor,

Thanks for the excellent explanation. You did not write it wrong the first time, I understood what you meant, and I agree with your point. Trying to control line tension with just increases in RPM from a G-Sensor may not be the answer for our entire pattern.

I feel that with our present ECL systems in gov. mode we have all the power and line tension we need in everything but the very tops of the maneuvers (vert 8, HG, 4LC, OH8s) when their is turbulence and or high winds. This is where I feel we sometimes need help. Yes, with our gov systems we can always add RPM for these less than ideal conditions, but this adds speed throughout the entire pattern, in places that it is not needed, or wanted.

Your example does make it clear that we have to be very careful that our solution does not have serious side affects, and make matters worse in some of the maneuvers.

Your 4/2 break is a good way to address the problem. Like Alan said, it has worked for over 50 years. There must be a way we can duplicate (or even improve on?) this 4/2 performance? It looks like we will need some type of feed back loop incorporating a G-Sensor, Airspeed, attitude information, and ? ..... Time will tell. :-)

You must be enjoying your excellent indoor CLPA during these winter months. I'm surprised you guys don't have more "Indoor CLPA" contests in the Northern hemisphere? ;-)

Thanks again for your help.

Regards, 

Igor,

Now you tell me! I wish I would have known a year ago, we were in Italy for a month and I would have come over and taken you up on your kind offer. Maybe next year? Your great flying indoor CLPA planes may start a trend over on this side of the pond. I'm surprised that the Bob and Dean team don't fly one during their NE winters? We don't have a winter where I live, so we miss out on indoor flying, and we miss out on a building season. But it's not all bad, I'm going sailing this weekend, the forcast is for clear blue and sunny skies, 23C, and fair winds.

If you ever get over here in Southern California you are welcome to fly any one of my airplanes, CL or RC, or go sailing. :-)

Hi Gang,
Please humor me for just a second while I establish a sense of sober perspective ... then I will throw it out the window and engage in this fascinating discussion of the perfectly gilded lilly.

The existing setup: using a good quality, or fast response, RPM governor (with lots of "headroom" available for the sudden transient load increases at the beginnings of vertical climbs) will produce a World Championship if no other development occurs. We are already in excellent shape!

On the other hand, the urge to gold-plate this already lovely flower is irresistable

I'm with Igor on a bunch of this, as usual.
0) A little added horsepower, that comes early enough, is worth more than a lot of power that comes after the airplane has already decellerated.
1) I still think that the most robust system will be a governor that has "tweaks" added to the RPM setpoint, based on some maneuver-dependant feedback.
2) Pure centrifics is too late. I thought that the discussion established that pretty well.
3) Pure fore-and-aft acceleration/decelleration provides an incomplete picture, but comes earlier.
4) Every time the handle is "quickly" moved away from neutral the drag due to G loading, and control deflection, is going to increase for a third of a second or so. This fast movement of the handle always comes earlier!
5) The governor RPM "error signal" is an excellent  way to measure the airplane's need for additional power. (This is Igor's indoor setup)


So now I have a question. Does anybody know who makes the accelerometer used in the device that started this thread? It sounds like it could become a part of the solution. I love this stuff!

take care, friends,
    Dean

By the way, my idea about trying to optimize on a prop isn't original---I am sure the guys that use a pipe (claimed to keep rpm pretty constant) are in more or less the same boat. I would be interested in seeing how a piped ship rpm varies throughout the flight. It would be pretty easy to setup an Eagletree system with an optical rpm sensor on the spinner. I actually have one (the sensor), but I don't run any piped ships.

Dean,
I was waiting for your reply, since I was aware of the history of the pipe (you and Bob Hunt).
I am also aware most of these guys are running pretty big props, and often more than 2 blades, so I am guessing they have already traveled the same path I am now going down.

Also enjoy your Pattern column in Flying Models. Always enjoy the columns that teach me something. A lot of the FM columns do this (as well as the Model Aviation ones too).

Being mostly a full-scale flyer, I've been itching to try using an airspeed sensor to control the power from my timer, since that it is how we fly full-scale planes through aerobatics. Any comments on how well this would or would not work? I think it could work well on the level, compensating for going into the wind and the increased drag by giving more power to keep up the airspeed. Loops also would have the power increased going up and decreased going down, as in full-scale airplanes without a constant-speed prop. But are there places in the pattern where we wouldn't want the airspeed to stay constant?

Hi everybody!
Just to confirm what Igor says about the G-sensor. I have it on test on my Morane Epervier. Only 4 flights to now.The power increase comes a bit too late and remains too long, mainly during dives. At the moment with my settings, the level flight is too slow and acceleration comes abruptly, which leads to a "non soft" flying.
Wolfgang will come up with a modified sensor, I will test it as soon as I received it, and keep you all informed.
Take care, Thierry

Hello Thierry,
May I make a suggestion? Have you tried the G-sensor with the axis tilted aft of purely axial?
I assume that the G-sensor was set to measure centripetal acceleration, but if angled aft it will count forward decelleration like a loss of line tension. I wouldn't be surprised if the angle turned out to be more than 45 degrees (mostly fore and aft accelleration). This could greatly reduce the lag.

Please keep us updated, this is terribly exciting!

best regards,
Dean Pappas

Exactly, Igor.
I don't expect it to be a solution as much as another valuable piece of data.
I still like your approach as it resonds to changes in load both in transient and at steady-state.
Maybe it would work well enough

Dean