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General control line discussion => Open Forum => Topic started by: John Miller on September 08, 2009, 08:41:05 AM
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Some years ago, there was a retract controller developed specifically for our CL models. It had a built in adjustable timer to raise the gear, and an onboard mic, listening to the engine. When the engine quit, the retracts would lower.
3 questions, Are these units still available? Who was the manufacturer? does anyone have one they'd be willing to part with?
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Werwage and Dean Pappas were working on a set up at one point...
W.
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I had one I never used, but I sent it to Chris McMillan. You might get ahold him to see if he plans to use it. Go to "members" here and look him up.
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The easy way is to buy either a JMP-2 or Ztron timer--the CL one we use for our electric motors. They include specifically a retract timer which would pull the gear up 10s after a programmable time (the time most of us use to turn off the motor as we walk out to the handle. Then at another fixed programmable time the gear servo is lowered.
For powered flight, I would set the delay time to ~20 seconds, then push the start button just as I walked out to pick up the handle. The gear would come up 30s after I pushed the button. (roughly 2 laps after takeoff).
Here is a link.
http://www.bsdmicrorc.com/index.php?categoryID=46&offset=8
The JMP-2 CL timer is at the bottom of the page, and the Ztron CLT-3 is the next page. COst is $30 for either one. I have both, and although I don't use the retract option, I can recommend either one.
Will Hubin (on this board) also makes timers, so you might want to email him too. I think he makes one with a retract feature (or he could make you one.)
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The easy way is to buy either a JMP-2 or Ztron timer--the CL one we use for our electric motors. They include specifically a retract timer which would pull the gear up 10s after a programmable time (the time most of us use to turn off the motor as we walk out to the handle. Then at another fixed programmable time the gear servo is lowered.
For powered flight, I would set the delay time to ~20 seconds, then push the start button just as I walked out to pick up the handle. The gear would come up 30s after I pushed the button. (roughly 2 laps after takeoff).
Here is a link.
http://www.bsdmicrorc.com/index.php?categoryID=46&offset=8
The JMP-2 CL timer is at the bottom of the page, and the Ztron CLT-3 is the next page. COst is $30 for either one. I have both, and although I don't use the retract option, I can recommend either one.
Will Hubin (on this board) also makes timers, so you might want to email him too. I think he makes one with a retract feature (or he could make you one.)
What happens with this timer when the engine flames out during a maneuver? Forced belly landing?
Edit-the one with the microphone(the one John requested) sounds like the best bet for IC engine usage. I guess one could use a tach sensor circuit pointed at the prop; could do the same thing.
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What happens with this timer when the engine flames out during a maneuver? Forced belly landing?
Edit-the one with the microphone(the one John requested) sounds like the best bet for IC engine usage. I guess one could use a tach sensor circuit pointed at the prop; could do the same thing.
Oh yea, I forgot about that quaint trait of a glow engine. LL~
I knew there was some reasons I like electric so much! y1
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Bob Whitley had it in a Mustang. Article was in a Flying Models back in the 90s from memory. Circuit board plan, electronic list etc for making it.
HH
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Here I go again...kidnapping another post about retract gears.
Although retracts have received more than their share of BAD REVIEWS from the majority of big name Icon CLPA flyers about how WE NEED ALL THE DRAG WE CAN GET THING-THANG-THOUGHT.........
Years ago....I had the outboard landing gear wire snap off my old Super Chipmunk while flying in a golper hole filled school play field near our home in Auburn. My son Ryan...who loved to fly my old Big Iron and Voodoodandies...had become quite a hand launch master.
I removed the other landing gear....and with Ryan's great hand launch technique, flew about 4 or 5 more flights just before dark.
I WAS ASTOUNDED AT JUST HOW MUCH SMOOTHER, AND PRECISE THAT OLD CHIP FLEW WITHOUT THOSE LANDING GEARS?
WHY?
I really couldn't say....Was the improvement due to less over all drag over the wing...or perhaps a miss aligned wheel pant...or a slight shift in the CG?
I was especially interested in seeing whether or not I could notice any "increased speed or wind-up in flight. I remember that the wind that eve. was also pretty brisk from the north and I can safely say for certain....I didn't experience any increase in speed...flying that model without the gears?
I felt so certain after that flight that retracts were truly something worth the effort. The very next day I drove down to the Kent Model Shop and bought a pair of those new little lightweight Robarts...
that I still have sittin in a box out in the garage....wastin' away in Gig Harborville! LL~ H^^
attached is still one article and magazine that I can just not part with.....who started all those games in my pea-brain about the possible advantages of retracts in CLPA?
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Don I remember that article from back in the day. It was clever, and unique, but relied on several things happening just right, to work right. Murphy is always with us, so I'm looking for a more fool proof way to control retracts.
I witnessed Bob Whitely's use of the unit I'm looking for at an early 90's VSC. It worked fine, except for problems related to the fact that he was using an air retract system.
I want to use retracts for several reasons, some of which you've alluded to.
Gordan Delaney's original classic legal twin, "Two Much" had retracts. He used a free flight timer, that would raise the gear, and after a fixed time, would lower them for landing. He has a great story about a test flight, flown by our buddy Jimmy Rhoades. He was flying over asphalt, the plane was new, and they were test flying the night before the old Buckeye Meet in Arizona. The airfields asphalt was extremely rough.
The gear came up fine, and Jimmy put in a good flight. Afterwards, he did level laps waiting for the timer to power the gear down. Lap after lap, until the engines quit. The gear was still tucked away.
Not wanting to mess up the finish on Gordy's brand new plane, he started whipping that big twin around. He whipped for several minutes, and still the gear was up. Tired and out of breath, he yelled out to Gordy that he better get in there and take over, or he was going to belly land the plane.
Gordy took over with the whippingand after a few minutes he was also tired and out of breath. He had decided that he would just belly land the plane and hope for minimal damage. He set the plane up into the final gliding approach, committed to a belly landing.
As the plane was decending, he heard a click, and then the whirr of the retract motors. He watched the gear come down and lock into place. The plane was saved.
It seemed that vibration had affected the timer. That's why I want thee sound activated unit.
The plane I'm planning on using, is also a twin, but much smaller than Gordy's. Because of design elemants, the gear has to be somewhat long and gangely looking. The plane will look a lot better in flight with the gear up.
I may have a lead on a unit. ' got my fingers crossed. H^^
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Les Nering, a block-away neighbor of mine, was involved in the development of the sound-actuated retract controller. He still has some units left and is interested in selling them. I can give his address to anyone who is interested in obtaining a unit. (I do sell "timers" for electric C/L flight that include retract capability. The servos designated as "retract" servos swing to one extreme with throttle or pulse widths up to about half throttle and swing to the other extreme with throttle settings greater than about half. My timers/flight managers use a little 8-pin microcontroller chip to generate the pulses corresponding to the full throttle range, so it is not difficult to add a retract capability and the microcontroller would make it possible to use a regular servo and adjust the retract time by stepping the pulses and delaying between them.)
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Les Nering, a block-away neighbor of mine, was involved in the development of the sound-actuated retract controller. He still has some units left and is interested in selling them. I can give his address to anyone who is interested in obtaining a unit. (I do sell "timers" for electric C/L flight that include retract capability. The servos designated as "retract" servos swing to one extreme with throttle or pulse widths up to about half throttle and swing to the other extreme with throttle settings greater than about half. My timers/flight managers use a little 8-pin microcontroller chip to generate the pulses corresponding to the full throttle range, so it is not difficult to add a retract capability and the microcontroller would make it possible to use a regular servo and adjust the retract time by stepping the pulses and delaying between them.)
I should note that timers like I am referring to, and the ones the Will makes don't have vibration issues! n~
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John..
Best wishes...on finding the right retract system that works....I too had heard that "Whippin good story about Gordon's race against time. H^^ LL~ LL~
Aerodynamically...I can't help but think retracts are something to consider. Controling speed using drag devices, at least to me...for CLPA models....are self defeating in nature? ???
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Thanks guys. Electric power would solve several problems, but I'm still deep into the "wet" power, and enjoy the challenge getting two engines to run right together.
I'll look up Les Nering.
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Some how the name Jomar or something like that comes to mind as the manufacturer of the unit. I will see if I still have the Magazine that has the article about the unit.
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Hi guys,
John C is right Jomar has a controller for $39.95 - I just googled Jomar electronics and went to acessories and it is the last item on page 2.
Pat Robinson
edit link added- http://www.emsjomar.com/SearchResult.aspx?CategoryID=6
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Yep, that's the one.
Thanks to all for their help.
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I wonder what happens on this one if you have an engine start and stop several times, before it finally dies? Will they(gear) be up or down?
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I wonder what happens on this one if you have an engine start and stop several times, before it finally dies? Will they(gear) be up or down?
Or someone starts up their engine in the pits! S?P
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About 15-18 years ago I spoke with Joe about designing the Jomar retract unit. He sent me two prototypes and the one Jomar now sells is the the one I determined was the best one. It does indeed us the sound of the engine to control the gear movement. Dead simple, it only hears the engine in your plane. The gear retracts after a set time and only extends when the engine stops running. Works everytime. I addressed all the questions posted here and you can get the article from the mag it was in except I can't remember which mag it was. I will ask Keith 'cause he keeps everything. Joe sold the system to Jomar sometime ago and that is why they now sell it. It's a good set up electronically and easy to use. RJ
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The magizine is Flying Models Sept 1994 page 46.
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I have three planes that have used the Jomar controller. The engine has to be stopped totally before the gear comes down. Never had an issue with the unit - always worked flawlessly. Have in two different twins and
I really like it. Once pancaked my plane upside down and as soon as everything stopped, the gear popped open.
Used the small battery pack as tip weight. Could move it to adjust tip weight as well.
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Thanks everyone who replied on the retracts for C/L. I have the article which was in Stunt News May/June 2007. This is regarding the Jomar unit and this is the one I want to buy but while the advertising comes up on the internet including this item I can't seem to put through an order or using the phone number in the add I get a out of service response. Maybe it is set to only respond to the U.S. calls I'm not sure. In any event thats the one I"m after.
Gerry B