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Oct 10, 2001, 04:11 PM
Thread OP

Can I use the "Endo" units in scale plane with success?


I am looking to "electrify" a twin scale project, a C-160 Transall, the one manufactured by www.giantscaleplanes.com. I bought this kit from someone who felt it would not be suitable for glow engines, which was what they wanted to do. I have read through the search of the archives about the "endoplasma units" with the GP gearbox. I am new to electrics but from waht I had read I was figuring to use an Astro geared motor with equilence to a .30 size glow engine turning 10X6 props. Now the question is could I use this more economical Endo unit as a suitable alternative, bearing in mind that this plane may not fly anyways. The projected weight RTF is about 6 lbs. It has a fiberglass fuse with foam wing. If some of you have experience with this, I would be most interested in getting the stock numbers of the gear box and pinion gears necessary to make this work. Also would you suggest a 16-20 cell pack for both of these motors, or am I way off here?
Thanks for your help.
Tom
(A glow man, looking for conversion)
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Oct 10, 2001, 04:57 PM
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GWRIGHT's Avatar
I did a conversion of the hobby hangar OV-10 with two endoplasma's and 20 cells initially, later dropping down to atomic force motors. The endo's don't like 20 cells in series although they behave great on 10 cells each in "singles". I've currently got equipment removed from the plane, but plan on installing 2 ESC's in it so i can run the motors as two seperate 10 cell setups on 10 cells each. I had it geared 4.6 to one with 11X10's initially. It flew at 7.5 lbs, and has retracts. With this initial setup it was VERY FAST, and climbs were exhilirating,.. well above 45 degree climb angles. I later dropped to 11X8.5's, then 11x7's because it was jut too overpowered with the 11X10's on the endo's. I had a few problems with motors due to the 20 cell setup with the motors in series. I've ran these motors hundreds of flights in singles on 10 cells, so I would go with 2 ESC's and two packs if I were you, and planning on 20 cells. when ever I get around to putting servos back in it, and fixing a couple "dings",.. I plan on two seperate power systems, plugged into different channels and mixed in the radio. Should provide for good flat spins with one prop at full speed and the other one stopped
Latest blog entry: blog
Oct 10, 2001, 05:02 PM
Based on what Ive seen the Endos do, I think they could easily handle the task of your conversion!

Based on power output, the geared Endos on 10 cells puts out the power of a good .30-.40 sized glow engine - at an excellent value too! The only downside is how much prop can you swing? The Endos really work best spinning around 12 inch props - does that cause a problem with clearance on the model?

If so, I havent run the numbers but Im sure you could use around 10 inch props with good success on the Endos. Anyone already have the data handy? Keep in mind - the more prop you can throw around, the better! Whats the maximum clearance you have between motor and fuse on that plane? Whats the largest diameter prop you can fit?

For wiring this type of twin, Id suggest doing it all seperately. What I mean is each motor/gearbox has its own ESC and battery pack. IF you were to run both motors on 1 ESC and 1 10 cell pack, youd pull nearly 60-80 amps - thats too many amps for most packs to result in decent flight times.

For ESCs, the best choice would be the new Great Planes CS50s. Each ESC/motor combo is fed through its own pack. The ESC's then use a "Y" harness between their receiver leads and plug into the throttle channel. That way, they both are controlled by just one throttle.

For packs, I think the better suited ones personally are the 10 cell packs of CP1700s. They weigh almost 5 ounces less per 10 cell pack than 2400s...thats a 10 ounce savings for 20 cells! That's over 1/2 a pound...and a good chunk of change. "Real time" flights on the 1700s would be 4-7 minutes, depending on throttle management. With 2400s, youll get 2-3 minutes more, but of course you add that extra weight! Tony La makes some of the BEST packs - end-to-end soldered and an excellent value. Visit him and tell him Jason sent ya!

http://www.eflightpacks.com

Sorry Im not more specific - I need to crunch the numbers or maybe someone will beat me to it. Basically, I just wanted to toss in my support because I think it can definitely be done. It wont be cheap, but a LOT cheaper than Astros or brushless!

Good luck!

Jason
Oct 10, 2001, 08:01 PM
Registered User
Brad Trent's Avatar
DocYates:
Electric twins are great! I've destoyed 1 20 cell ship due to pilot stupidity (rolls @ 20', 1 went wrong), but still have 2 twins in my fleet. One is a 48" sporty S400 ship, the other is a 76" scratch built Partenavia of about 6.5 lbs, wing area ~900sq.in. The large one is presently using 2 Mag.Mayhems, geared 3.5:1, 11x9 M.A. props, wired in parallel. This setup flies well using 10xRC2000 cells, since each motor is only drawing 16A as propped. I've tested it with the same gearing and props, but wired in series on 20 cells, and found that the extra weight ate up any increase in power and duration that the series setup might have provided. Since 1 of the MMs has worn out its front bushing, I'm going to try a pair of Atomic Forces, which is a similar motor to the Endo, but slightly milder at 17 turns vs. 16 in the Endo. Motocalc gives good results with these motors wired series, on 14 cells, geared 3.8:1, with the same 11x9 props that I now use on the plane. I'll test this setup as soon as my GP gearboxes arrive at the LHS, hopefully later this week. When I do fly it, I'll report back here.

You're certainly on the right track with your twin, but much depends on the wing loading, so fill us in on span, area, and weight less motors and cells if possible, and we can get more specific about your power needs.

Hope that helps,
Brad.
Oct 10, 2001, 08:22 PM
sb1
sb1
Brad,
You can replace the bushings with bb in the MM, you may know this already but thought I would bring it up. I read some threads about using the bearing kits used in the r/c cars, around $7-$10 dollars for a set of 4 as I recall.Here is one site that gives details,http://ijcooper.20m.com/Hobby/bear2bsh.html
A little off topic, sorry.

sb1
Oct 10, 2001, 08:56 PM
Just an average RC'er
Jim McPherson's Avatar
DocYates,

Hi, I'm down here in Tuscaloosa until the first of January. I'm about to have an Endo setup up and running as soon as hobby people ship me my kit. I've got the Endo and power system here, and as all of the above guys have said it is a very potent combo, I haven't seen this kind of power since going to the glow field. If you ever swing by this part of the state look me up and I'll show you what electricity can do.
Oct 11, 2001, 07:24 AM
Thread OP

Props??


Thanks for the help fellas. I was wondering about the props as well. Is it necessasry to use "electric" props on these setups or could one use regular props. I was thinking of using three bladed 10X6 or similar to give it a more scale appearance. Sorry for all the questions, this is all new to me.
Tom
Oct 11, 2001, 07:34 AM
Registered User
GWRIGHT's Avatar
If you use props other than APC "E" props (electric specific), you'll see higher amp draws (lower flight times) and less performance. REally need to use the "E" props. For 4.6 ratio, 12X8 APC "E" or 13X7.5 sonictronics "E" folder are both good for max thrust, but pitch speed is around the low to mid 50's. For more speed and a touch less thrust, the 11X10 APC "E" prop works well. Properly timed, the peak current is around 40 amps with any of the above, but with the throttle pulled back for "normal" speeds, average current is generally in the mid 20's.
Latest blog entry: blog
Oct 11, 2001, 09:20 AM
AMA 697691 / FAA 13675
Hi Tom (Doc),

I use a 2.5:1 geared Endoplasma with a Kyosho 9x6 prop on a 3lb sport plane and it goes like a bat-outta-hell!

Doubling this for your 6lb ship seems reasonable. Using a pack of CP1300SCR (or 1700s) per motor or a single 8-cell 3000RC NiMH pack may provide reasonable duration.

Check out my RPM and current specs. under the Kyosho Flash below:
http://www.isc.rit.edu/~gjc9518/aerobati.htm

Good luck!
Latest blog entry: Greg's Web Hangar
Oct 12, 2001, 03:56 PM
sb1
sb1
GWRIGHT, Greg

Since you both have experience with both the endoplasma and the atomic force can you give me any advice as to which would be better for a SIG LT-25 project. I have read Bernard Cawleys article and have considered the MM w/3:5 to 1 g/box on 10 cells, but he indicated performance was sedate but flyable. I would appreciate any insight any of you would have on this. The LT-25 should weigh 4.5 to 5.25 lbs ready to fly with 724 sq inches of wing area, should provide nice stable flight habits, I don't want a rocket ship but something with respectable performance and reliability too.

Thanks,
sb1
Oct 12, 2001, 08:11 PM
Registered User
GWRIGHT's Avatar
If you don't mind spending some bucks on a nice gearbox,.. use the endoplasma, and the MEC "monsterbox", with 96 tooth spur and 12 tooth pinion, giving 8 to 1 ratio. Will probably need taller landing gear to swing the 18X10 APC "E" prop though. On 10 cells, this pulled a 4.5 lb plane VERY NICELY,..would hover for a bit even. If you want longer flights, even the 16X10 at this ratio makes gobs of thrust, and with lower current. If you've seen the videos from the NEAT fair with my big yellow plane (the original E3D), that's what was on the front of it. It was 64" span, 1150 square inches, 72 inches long, and 4.5 lbs. This setup and 10 cells was a bit more than "adequate"
Latest blog entry: blog
Oct 12, 2001, 08:48 PM
sb1
sb1
Yes, I have seen the video from NEAT and it is incredible what that combination is capable of. That is what has me interested in the endo and atomic force motors, I have a MM direct drive on a kyosho 180(foam) It weighs 3 lbs and it has all the power it needs on 6 cells. Not sure if I can ever fly as good as you to use all that power, but want decent power for this plane. All I have bought so far has been the master airscrew g/box 3:5/1 and their 12x8 folding prop and want to have a better idea before I start buying motors and batteries. The MEC g/box sounds like a good option, do they have a website?
Thanks Gary for the info and good luck with your kit, went to your site but it looks like it is under construction for the time being.

thanks again,
sb1
Oct 12, 2001, 09:21 PM
Registered User
GWRIGHT's Avatar
Yes, the site is just being constructed. A flying friend of mine is doing it. i got him the text and pictures today for the bio and E3D pages, so hopefully they'll get up this weekend.
try http://www.modelelectronicscorp.com The gearboxes are GREAT except for one thing. He uses a roll-pin to attach the spur gear to the output shaft, and spinning the really BIG props, with the brake activated on your ESC, it tends to shear them fairly often. His recommendation was to cut a piece of 1/16" music wire which I did, but eventually sheared it,..... a few times actually. I found some 0.064" drill bits in the railroad section of the hobby shop, cut a piece off one with a dremel, and it worked great, no more problems, and cost almost nothing. Other than that, those gearboxes are bulletproof. he has spur gears of 70,80, and 96 teeth if I remember correctly,..and unless you really have to waste power making speed,..you want the 96 tooth so you can swing really big props and make huge thrust very efficiently. Even with the 96 spur, you can get way down around 5 something to one. if you use 48 pitch car pinions,..I think Bolink has them to some ridiculous size like 30 or so teeth,..so you could get below 4 to 1 ratio with that,..although I don't know why you'd bother. I know at 6.4 to one (15 tooth pinion) a 15X10 APC "E" and the endo on 10 cells has stump pulling power and decent speed for sport flying. You can interchange a 14X12 for a touch more speed. At 8.0 to one with an 18X10 , timed correctly, you have right at 4.5 lbs thrust, but just under 40mph pitch speed, and a little under 40 amps. You can go all the way to 9.6 to one, and reduce the power a bit for longer flights. I like lots of "1st gear" and don't care much about speed. I've found it's much much easier to use the energy for thrust than speed,..i.e. you can get lots of thrust on little power,..but to add a bit of speed you have to greatly increase power,.. so I think electrics' really have a niche for high thrust low speed stuff. Of course the hotliners and F5D stuff shows that you _can_ get speed with electric,.. but the flight duration goes down exponentially with an increase in speed.
Latest blog entry: blog
Oct 13, 2001, 12:19 AM
sb1
sb1
Thanks Gary,
I really appreciate the advice on the g/box and ratio's. I am not into speed much either so this info helps a lot.

Thanks,
sb1
Oct 15, 2001, 11:05 AM
Registered User
Whats the max sell count that a Endo can handle (safely).


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