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Old Nov 17, 2001, 05:41 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
new zero experiment results

I had been flying my jk aerotech zero on a apc 12x10-e,
( for full specs search in foamies under "zero pics"),
but having broken my last 12x10 I resorted to a apc 12x8-e instead. I also disabled the bec and Llvc and used a seperate rx batt.

Motocalc says the pitch speed is barely adequete to fly the plane, and it turns out motocalc is right. Climb rate, climb angle and top speed are all way down over the 12x10, and to stay airborne, I had to keep throttle up around 7/8ths instead of 1/2 with the 12x10.

I was limited to some pretty basic stunts as I just could'nt generate enough velocity for decent vertical.

One interesting side note though. Since I no longer had to worry about the Lvc shutting me down, I decided to just keep flying one flight till power started to sag. I was up for about 10 minutes of mostly wide open ( but kinda slow) flight.

Motocalc predicts only about 4.5 minutes ( 30 amps) static run time, but at the predicted 51 mph top speed, it predicts to unload to only 14 amps and almost a 10 minute run time, even though its still wide open.

Apparently it really does unload that much as it really did run 10 full minutes.

BTW, the zero can easily handle the extra weight of the rx batt pak, and it sure was nice to know that throttling up late in flight won't shut down the prop.
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Old Nov 17, 2001, 09:58 PM
Giddy up!
Sal C's Avatar
Woodridge, Illinois
Joined May 2000
4,478 Posts
Interesting Dean about the longer flight times. I've never used a separate rx battery pack on any of my planes, but they're mostly smaller planes. I've got a few larger 10 cell planes on the building block for this winter. I plan on using an rx pack on them. Thanks for the info. Sounds like you're having a ball with that Zero, how about any of the other JKA warbirds? Corsair? P-51? Mig?
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Old Nov 17, 2001, 11:25 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
As a matter of fact, I have been giving some serious thought about that mig 3, but it will probally wait till christmas.

I do have a super sniper on order though, and if I'm lucky it'll show up monday so I can commence the building.

I also have my eye on that mini mustang they sell, but with a sp480 instead of a sp500 motor. I'm still working out the numbers in motocalc for that one, trying to get good performance AND 5 plus minute flights. Not easy though, with batteries being the biggest prob. I may have to go to a 10 cell pak to do it.
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Old Nov 17, 2001, 11:50 PM
Giddy up!
Sal C's Avatar
Woodridge, Illinois
Joined May 2000
4,478 Posts
Dean,
Are you talking about the 1/12 Mustang or the pocket version?

I have both. The pocket P-51 should be a strictly S400 ship (maybe even a 300). The 1/12 hasn't gotten rave reviews here on Ezone for a E conversion, but I'm sure it's possible.

Let me know what you come up with.
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Old Nov 18, 2001, 11:08 AM
Mike Swan
Oroville, California, United States
Joined Oct 2000
372 Posts
Hey guys,if you can cut wings and wanna brew your own,go here,www.theplanpage.Ocatch.com the Earl Stahl plan on the p51-D is very scale,and comes with options for drop tanks or missisles,dont know how much drag they will add but look really nice. i enlarged drawing on poster to 2.8 for 30" wing,made root 7 and tip 4 for 165 sq",making it all out of pink,just about done making templates for wings,using a clark Z 10.48%,i only had to increase tip a tad to get square inches up,you can hardly notice it,drop tanks will be blue foam,need to scrounge something up for missiles though,probably just sanded balsa square stock.and card stock fins.
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Old Nov 19, 2001, 01:24 AM
Mike Swan
Oroville, California, United States
Joined Oct 2000
372 Posts
Sorry guys,i tried my links not working either(NOTE) I did a search,if you type in( the plan page)the links there,and it works.Ive been having other problems,so its probably on my end with computer.The plan does make a very nice looking fighter ,so its worth a little leg work.
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Old Nov 20, 2001, 02:40 PM
Fixed Wing Fanatic
Jim Walker's Avatar
United States, TX, McKinney
Joined Jul 2001
2,344 Posts
Mig 3

I'm in the final stages of construction on my JK Mig 3. Still looks like I'm going to make my estimated all up weight of 40 oz. I'll definitely be doing the maiden flight this coming Saturday, weather permitting.

I don't know about anybody else, but I'm really disappointed with how sloppy it looks. Even taking into account that this was my first ever taped up foamy, I thought I could do better in the looks department. I know about slitting the edges of the tape to go around compound curves, yet I still ended up with a plane covered with wrinkles and puckers no matter how hard I tried. I do have several years experience with tissue/dope, iron on and various other coverings, but it sure didn't help me here. I'm not sure if I should even post a picture of it after seeing Dean's and Sal's effort.

I'm trying to remember what the main purpose for this plane is, namely to teach me to fly a fast aerobatic plane and take my piloting skills to the next level. I'm definitely counting on JK's claims of an outstanding flyer that can take a lot of punishment. I'm also hoping it will look good in the air when it's too far away to see all the wrinkles and puckers.

Hey guys, did you glue on your canopies or make them removable? I have my elevator servo and my reciever under my canopy. The rest is under the wing, so I'm thinking of just gluing my canopy on with goop and then I can trim it off if need be in the future.
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Last edited by Jim Walker; Nov 20, 2001 at 02:43 PM.
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Old Nov 20, 2001, 03:56 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
Hey Jim, don't be so hard on yourself. Taping is a skill that takes time to learn just like covering did.

Every plane I tape up looks better than the one before.

I'm hoping to finish up my jk aerotech super sniper tonight, and am actually very pleased with my tape job. Its coming out very smooth and even compared to the zero, which I was not all that pleased with. ( I will post pics when I can).

On compound edges, I wind up using small narrow strips of tape, overlapping as I go and always putting some tension on it as I smooth out the air bubbles. If, I get a wrinkle, I pull the tape back up just past that point and lay it down again. Winds up pretty smooth and even.

On my cockpit, I tape hinged it at the front, and stuck it down at the back with velcro. Works/looks nice and gives me easy access to my RX and RX batt which get used in three models.

One last thing, if you did'nt already, at 40 oz, the wing spar is'nt really optional unless you plan to just cruise around. I went back and added two spars after some hard pull ups at max speed had the wingtips bending up a good 6".

Please post pics when you finish. I'm really curious about the mig.

Dean
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Old Nov 20, 2001, 04:58 PM
tic
thunderscreech
tic's Avatar
New Cumberland, PA. US
Joined Dec 2000
10,936 Posts
Dean: the Robbe P-51 Mustang is flying w/ a 12x10 APC thin electric prop, however, all three props have been broken that we have.... we have some 12x10 pattern props though... I know they are heavier, (made for glow) but if they don't break on belly landings, that might be the way to go.. we've been breaking the e-props even landing w/ the prop horizontal.. the "radiator" belly scoop catches on the ground and tips the plane up.. Any idea how she might do on the pattern props?... It's a handful to launch as is, too much performance loss could be a disaster..
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Old Nov 20, 2001, 07:06 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
Thats interesting Tic. I have yet to break one of these props except during crashes with power on.

Does your esc have a brake? Mine ( kontronic 4001) does'nt and the prop appears to be powered up on final its spinning so fast, but apparently this allows it to move out of the way easily enough to prevent breakage.

If you do have a brake, you may be able to thwart it by cutting power earlier in the final. Most esc brakes only operate for a short time and then shut off.

Worth a try anyway.

Those 12x10 pattern props won't be as efficent as the e prop is, will definately be heavier, maybe enough to upset CG, and will likely have to be balanced too to avoid excess vibes.

Perhaps also you could put a small wire landing skid under the plane from the nose running backwards to stop the belly scoop from digging in.
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Old Nov 20, 2001, 07:14 PM
Registered User
Crete, NE. USA
Joined Jul 2001
259 Posts
Hi, Everyone!

I'm interested in the jk aerotech airplanes. What motors and batterys are you using ?

I have a MEC turbo ten sys. That I've been running on 8 or 10 cells.
Would this be a good setup or overkill?

Thanks, Don
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Old Nov 20, 2001, 07:17 PM
tic
thunderscreech
tic's Avatar
New Cumberland, PA. US
Joined Dec 2000
10,936 Posts
Landing skid has been made, actually, some nose weight was needed so the pattern prop may cancel out the need for the lead... I know when I tried a thin electric instead of a slowflyer prop on the skyscooter, performance suffered quite a bit.. Hope it's not so much on the Mustang w/ the mag mayhem, I'm thinking it won't be
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Old Nov 21, 2001, 10:06 AM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
Don H:

That motor should be very nice in one of these warbirds.

Just like the real planes they're based on, the faster you go the better they fly. No substitute for power here.

Mine uses a kyosho atomic force geared 3.8:1 with a 12x10
apc-e on 8 cp2400 cells. It was timed at 64 mph on this setup and flew very well indeed. The hand launch is a little difficult as you have to grasp the fuse pretty far behind the CG and it is a 45 oz plane. Throwing hard, flat and level takes some concentration. Its my only plane that I actually run a little to launch.

A bungie launch would prob make takeoff a non-event.


Tic: The slowfly works best at low power levels due to its very thin airfoil thats been optimized for low rpm operation. If you put real power to it, it could very well flutter in air.
The e-props are designed for higher power loadings and also are far stiffer.
The pattern props are much heavier yet for even higher power loadings and to withstand the IC vibes as well as the powered starters being bumped against them.

Let us know how it goes, but I'm guessing you'll have higher amps and less power.

One other thing. If the prop does'nt give, whats next in line that'll have to? Prob the gearbox shaft?

Dean
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Old Nov 21, 2001, 10:24 AM
AndyKunz's Avatar
Illinois
Joined Sep 2001
25,276 Posts
Quote:
Originally posted by kit basher
Hey guys,if you can cut wings and wanna brew your own,go here,www.theplanpage.Ocatch.com the Earl Stahl plan on the p51-D is very scale,and comes with options for drop tanks ...
That should be a zero, not an O.

Try this link instead:

http://www.theplanpage.0catch.com/

Andy
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Old Nov 21, 2001, 10:44 AM
Fixed Wing Fanatic
Jim Walker's Avatar
United States, TX, McKinney
Joined Jul 2001
2,344 Posts
Thanks for the encouragement Dean. I guess I will go ahead and post some pictures of it this weekend when it's complete. I'll just make sure I stand a few yards away with the camera....

I thought the spar would be needed at this weight, guess I was right based on your experience. I imbedded an 1/8 X 3/8 spruce spar from the center to about 4 or 5 inches from the tips. I also put three strips of strapping tape all the way to the tips, top and bottom. Finally I wrapped strapping tape chord wise on the center section, diherdral joints, and about two inches toward the tips before covering with white packing tape. There is still some flex, but it seems very strong and solid.

Don, I agree with Dean, more power equals more fun, within reason of course. Do you know how much thrust your super 10 generates? A friend of mine just bought a super 10, 80 amp ESC, 6:1 super gearbox, RC2000 Sanyo Nicads, and is going to swing a 13-9 prop. The outfit that sold him this setup claims it will fly his 52" span, 100 ounce Dymond Model TigerMoth ARF no problem. Talk about a HOT motor!! His super 10 is smaller than my magnetic mayhem yet it's going to pull 60-70 amps??? Whew......
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