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Old Nov 21, 2012, 05:28 PM
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Waverly, Nebr.
Joined Apr 2009
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The magic smoke

My watt meter arrived today so I will be able to get some numbers over the next 4 days on my setups so I can keep the magic smoke in. I am heading to the overpriced LHS after work today to pick up some connectors. I am going to make a box with various connectors on both sides of the meter to connect different batteries and loads. This should help prevent the dreaded "operator headspace error". The last thing I want to do is have that magic smoke get out due to shorted leads causing a lipo fire or burned components.
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Old Nov 22, 2012, 02:51 PM
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beerbrewer's Avatar
Waverly, Nebr.
Joined Apr 2009
252 Posts
Connector questions

Dear All,

I have done some searching on RCGroups and I need to find the answers to a couple questions. I don't like any exposed connections and am really considering going to all EC3 connectors since the male side is covered unlike the Deans Ultra where the prongs are hanging out in space and besides, they are a total pain to solder up. The EC3's are fully covered and are a breeze to solder.

What is the amperage rating of Deans Ultra Plugs?

Not that I need them right now, but are there higher rated EC3 connectors than the standard 60 amp?

I wish I had remembered to get some connectors when I ordered my watt meter. The LHS charged me $10.63 for 4 sets of T-plugs and I could have gotten 5 of them for $3.95 thru HURC. That is more than 3 times the price per set.
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Old Nov 23, 2012, 12:12 PM
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Waverly, Nebr.
Joined Apr 2009
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Well I fired up the motor last night and the magic smoke stayed in. I put it to full throttle for a few seconds and things were blowing off the table at just over 100 watts. That seems very low for power on a 4s spinning a 12 x 6 prop. I shut it down right away since a piece of paper was sucked thru the prop so I did not see what the amps were. There is no other way to say it but she really wants to fly but I need to finish all of the interior work first, (bat box, ect.).

I went to Omaha and checked out their HS of the same name as the LHS and what a difference. It is an RC super store. They have both indoor on road and outdoor off road tracks for the dirt buggies. The indoor is carpeted and they have lots of work benches for super tuning your racer. I did not see anything for gaming like the LHS, just lots of trains planes and automobiles I am definetly going back as their wood products are better than half price compared to here. I may finally get that donated Sig King Cobra up and running.
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Old Nov 26, 2012, 10:33 AM
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Waverly, Nebr.
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A real Senior and Cub

I am amazed at what was given to me this past weekend. I have to be truly thankful for this or I am one selfish and petty S.O.B. that does not believe in Santa Claus.

I was given a real Sig Kadet Senior and a Piper Cub this past weekend so Santa came early. I am just amazed at the size of the Senior and its wing. These two now make a minimum of 7 planes/projects I am to work on.

Now what am i going to do with another slimer 40 and 60? Garage sale?
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Old Dec 03, 2012, 12:00 PM
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Waverly, Nebr.
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I was able to get some more work done on the LT-40 this past weekend. I made sure that everything was clear and I ran up the motor WOT for a few seconds several times. I am pulling 496-499 watts max on a 12x6 prop and the air is really moving.

I cleaned out the old slimer goo from the elevator push rod and it works much better. How it got in there is anybody's guess. I wish I could have gotten more done, but sometimes life gets in the way of having fun.
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Old Dec 03, 2012, 05:34 PM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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You'll have fun with that Senior. A clubmate of mine way back electrocuted one with an Astro 40G cobalt brushed motor on 24 nicad cells - just over three pounds of battery. He also reckoned he'd added about another pound of brass tubing, wire and epoxy making it a two piece wing on account of that was the only way it would go into his little Bee-Em sedan.

We never weighed it - all were too scared to discuss 'weight' on trying to pick it up, so we let him carry it to the runway and I did the test flight.

It was still so easy going that you didn't so much fly it as watch it amble around. We even talked his wife into having a go with it. She barely knew one end of a model from the other, but with a little briefing as to left, right and don't touch that other stick (throttle!), she spent around ten minutes guiding it around the field with no real drama.

With a LiPo battery, it will be more like 'Now, where DID I put that battery'? than 'Howineck can I get the battery in there?'

D
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Old Dec 21, 2012, 02:32 PM
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Waverly, Nebr.
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Santa skipped me

Well when ya work at an institution of higher learning, you can have a nice 2 week break over Christmas and New Year. I had big plans to finish the Lt-40 conversion and start on another electrocution. Unfortunately, when the mail was delivered here at work this morning, my package was not there. No props, batteries, esc's, motors, arming switch or wiring. I am going to be a bit bored over break with all of the new snow and no toys to work on.

Terry
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Last edited by beerbrewer; Dec 21, 2012 at 02:47 PM. Reason: correct wording
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Old Dec 21, 2012, 11:50 PM
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Aw that sucks. Had 4 boxes turn up yesterday. I may surface in February
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Old Dec 22, 2012, 02:32 PM
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beerbrewer's Avatar
Waverly, Nebr.
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Yeah, it does suck. I got the tracking number and my package has been doing some extra traveling. It took 2 days to go from FL to MI, another 2 days to go back to FL. As of today, it has left FL for destinations unknown.

Only the US Postal Service can be blamed. I paid the extra for the 2 day delivery so it would be here Wednesday Dec 19.
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Old Dec 24, 2012, 12:50 PM
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Time to drag out the sheets of depron make yourself a knock-yourself-dead design. Wokiging on a KfM-3 Depron version of the RCM Shrike Commander design.

http://www.rcgroups.com/forums/showt...0#post23609718
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Old Dec 26, 2012, 03:49 PM
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beerbrewer's Avatar
Waverly, Nebr.
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Thanks bryocat,

I have pulled out some blue fff and have been doing some cutting and gluing. I guess I am starting another project before I finish this one. It is a Blu-Baby for a friends daughter.

I did have a chance to do some testing of the power and possible flight time over this past weekend. Just under 500 watts WOT on 4s & 12x6. I really pushed the power use on the first run and went easy on the second run. With the first run I used 4kmAh in about 20 min by running half throttle and then WOT for 15-20 sec (never went over rated the amps on anything pulling 31.3 amps WOT). On the second, I drained about 2kmAh using steady power draw of 100-125 watts for 20 minutes. So with this setup, I hope I have achieved my goal of 15-20+ minutes flight time.

I will have to wait for the larger prop and battery to see what 5s & 13x6.5 will do. I am hoping for around 650-720 watts and get closer to max rating for current draw.

Hope everyone had a safe and peaceful holiday yesterday.

Terry
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Old Jan 03, 2013, 01:30 PM
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Package has arrived

Well my parts arrived today so I will try to get some work done on the conversion before Monday. As I stated before, only the USPS is at fault, HURC is always spot on in their costumer service.

I am going to get some pics taken and get them posted soon.

Terry
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Old Jan 15, 2013, 10:55 AM
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I finally had a chance to finish testing all of my larger props on both of the 4s and 5s batts, I will post the numbers for each respectfully. I am really impressed in the difference between the Windsor Master Airscrew and the APC props. Previously I went WOT very quickly and I would spike the numbers getting as much as 100 watts difference since my meter only takes readings every .4 seconds. This time I gently brought it up to WOT so as not to spike. The first 3 are old slimer props.

The setup is, Emax GT3526/05 motor with a Skypower 60A ESC switch mode BEC.

10x6 Windsor: 320.9W, 20.54A; 565.4W 28.72A
10x6 APC: 344.2W, 21.80A; 617.8W 31.56A
11x6 Windsor: 372.6W, 23.74A; 663.9W, 34.33A
11x7 E APC 423.7W, 27.31A; 729.0W, 38.44A
12x6 E APC 469.0W, 30.39A; 807.6W, 42.84A
13x6.5 E APC 557.7W, 36.89A; 925.6W 50.03A

The motor is rated at 950W and the ESC at 60A so that is all good. If I go with the 13 inch prop on 5s I should probably bolt the wing on vs. rubber bands since it would be a 3D Lt-40 trainer. Truthfully, I feel that the 11x7 would work just fine.
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Last edited by beerbrewer; Jan 15, 2013 at 04:46 PM. Reason: added setup info
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Old Jan 16, 2013, 04:46 AM
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Quote:
Originally Posted by beerbrewer View Post
I finally had a chance to finish testing all of my larger props on both of the 4s and 5s batts, I will post the numbers for each respectfully. I am really impressed in the difference between the Windsor Master Airscrew and the APC props. Previously I went WOT very quickly and I would spike the numbers getting as much as 100 watts difference since my meter only takes readings every .4 seconds. This time I gently brought it up to WOT so as not to spike. The first 3 are old slimer props.

The setup is, Emax GT3526/05 motor with a Skypower 60A ESC switch mode BEC.

10x6 Windsor: 320.9W, 20.54A; 565.4W 28.72A
10x6 APC: 344.2W, 21.80A; 617.8W 31.56A
11x6 Windsor: 372.6W, 23.74A; 663.9W, 34.33A
11x7 E APC 423.7W, 27.31A; 729.0W, 38.44A
12x6 E APC 469.0W, 30.39A; 807.6W, 42.84A
13x6.5 E APC 557.7W, 36.89A; 925.6W 50.03A

The motor is rated at 950W and the ESC at 60A so that is all good. If I go with the 13 inch prop on 5s I should probably bolt the wing on vs. rubber bands since it would be a 3D Lt-40 trainer. Truthfully, I feel that the 11x7 would work just fine.
If it fits I'd go with the 13" prop on 4S, and 13x8 in preference to 6.5" pitch. 13x8 4S should give you more thrust and the same pitch speed as 11x7 5S, for the same power consumed. The better thrust efficiency of the bigger higher pitched prop should translate to better flight times, assuming you use a 4S that weighs about the same as a 5S. And performance will be great.

Must be getting close now!
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Old Jan 22, 2013, 01:38 PM
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beerbrewer's Avatar
Waverly, Nebr.
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Thanks scirocco,

Yes, I am getting closer. I will replace the wheels before the maiden since they are woobley and turn poorly. Also I need do some patching on the monocoat covering.

I feel that a lower pitch is better on the Lt-40 since it is designed for slower flight for beginners. I have tried to find where I read it but the way I understand this is that the pitch is like gearing on a bicycle or car. In high gear it is hard to get going vs low gear and this massive wing wants to cause "ballooning" if coming in too fast for a landing. Can't forget to mention the drag the wing creates at higher speed. This baby is a floater and gentle flyer so I feel slower is better and have the power to spare. If I wanted, I could easily fit a 14 x 7 inch prop on it with the way I built the new motor mount since I have 8.5 inches from the centerline of the motor to the ground.

If and when I get my donated (free) Sig King Kobra going I fully agree with the higher pitch prop that you are recommending.

I did some playing around on the battery hatch and for people who do not know, there are some very strong magnets in hard drives. To remove them you need to bend the metal backing to remove them. The magnets are quite brittle and will break if you try to pry them off.
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