Author Topic: E-Nobler build thread. (Read 3666 times)

andreas johansson · « **on:** May 13, 2009, 01:16:38 AM »

Hi Guys!

I will use this thread to show my progress of assembling my electric TF Nobler. Lets start with some questions:

1. Shall I mount the motor with some sidetrust (word?), you know, a degree or two to the outside of the centerline. In my glow powered Nobler (with a 10x5 prop) the engine follows the centerline and it works perfect.

2. How strong does the motor mount need to be? Is it enough with a 1/8" plywood plate and some 1/4" balsa stringers and build it like a small box and then glue it to the firewall? The motor will be rear mounted.

3. How to mount the battery in a secure way? Velcro?

Andreas

Alan Hahn · « **Reply #1 on:** May 13, 2009, 09:48:01 AM »

Andreas,
Take it from someone who has been there---make your mount as strong as you can (within weight limits of course). You want the weakest link to be the propeller, not the motor mount. What happened to me was that my prop dug in during a takeoff. Before the ESC could cut power the amperage spiked to >80A. Since I had used 3/8" square balsa sticks to glue my plywood motor mount to the firewall, the tremendous motor torque ripped the balsa off the firewall. Now if that was all, then I would have been happy!

But no, that was not all

. Since now the motor was let loose from the firewall, but still under power, it began to turn also and pulled the "guts" out of the nose of the plane. Mercifully one of the motor to ESC plugs finally pulled out, but not before the motor/ESC/prop assembly managed to also spin around and chew a bit out of the wing leading edge. In the end, all the wires frpm the ESC to the motor were twisted into a tight spiral. Othr than some cut insulation though, the motor, ESC, and prop were all ok.

And it did it twice to me

before I wised up and replaced the balsa sticks with equivalent sized maple.

later edit---added photo of carnage!

andreas johansson · « **Reply #2 on:** May 13, 2009, 12:38:56 PM »

Ok, Alan I´ll check my wood pile for some maple wood.

Andreas

Dennis Toth · « **Reply #3 on:** May 13, 2009, 04:46:30 PM »

Andreas,

This should be a interesting thread that could provide lots of information for new comers. I like your format of asking questions and comparing it to IC approach.

On engine off set - electrics use the same basic rules as IC. If you like engine off set for IC use it for electric. 1 degree is OK.

On the motor mount - I agree with Alan, again build it fairly strong as you would for a modern well balanced IC (don't need to build it for excessive vibration like for a ST 60 or Fox 35).

Consider doing a front mount motor arrangement. Seems there have been a few motor failures due to flexing in hard corners that appears to wack the magnets and take out the motor on the rear firewall mounts units. The front mount approach kinda balances the shaft forces over the front motor bearing and reduces the chances of a can strike.

Battery mount - seems that a clean top hatch is the way to go. I have used Velcro strips on the bottom of the pack to keep it from moving front to back and two Velcro straps to keep it in place up and down. Before you select the location of the battery pack put the complete ship together with motor, switch, ESC, Timer, prop, wheels, cowl and spinner, then use the pack to get the CG to the recommended starting location. Make sure you can adjust the location of the pack +- 3/4" from the recommended CG location.

Best, Dennis T

Dennis Adamisin · « **Reply #4 on:** May 13, 2009, 05:16:17 PM »

I think you can plan on the E-Nobler to be at least as powerful as any IC Nobler you have - thus the same "rules" would apply as you are used to as far as thrust offset. PLUS with E-power you may soon want to try reverse rotation propellor which by all reports tends to improve line tension. Thus I would vote no to engine offset.

I recently mounted a motor using built-in dowel rod stand-offs as shown in the picture. It is a very sturdy installation, and might work for you if the stand-off distance is not too great. OF COURSE you have to still have a really good firewall installation.

I have built ECL with battery hatches on the bottom or on the top. Top hatch is better, but the bottom hatch will be easier, especially starting with the ARF.

andreas johansson · « **Reply #5 on:** May 14, 2009, 12:13:16 AM »

Hmmm, Dennis seems to be a popular name in ECL

Dennis T: I agree with you that a front mounted engine is preferable, but the front part of the cowling on the NoblARF is very tight so I dont think its possible.

Dennis A: Reverse rotation is very tempting, but I will try a "normal" setup first. Wasnt that the reason why GMA flew clockwise circles?

As this thread will focus on the E conversation of a Nobler ARF I will not write much about the general assembly of a NoblARF. However, here is a list of the modifications I intend to do:
1. Replace the stock bellcrank and lead outs with a 3" Brodak bellcrank and bushed lead outs. This is a must!
2. Carbon fibre pushrods with ballinks where its possible to use them. Not sure here, the stock pushrods works pretty good.
3. Replace stock clevises with high quality german made clevises. This is a must!
4. Replace the stock landing gear with real 1/8" music wire OR a carbon fibre landing gear from carboncopy.co.uk

Andreas

Dennis Toth · « **Reply #6 on:** May 14, 2009, 12:25:28 PM »

Andreas,

I know what you mean about the tight nose. If you are using a molded fiberglass cowl (I think Brodak has them) you might have just enough room to use the front mount similar to the one I have on the Excitation. It is basically a half round former that rests on the motor mount and drops down between them to get the last motor bolt. It is held to the motor mount via "L" clips with the motor bolted to the former and the bottom fits into a slot in the plywood on the bottom side of the motor mounts. This has worked well for me on two ships.

Best, Dennis T

andreas johansson · « **Reply #7 on:** May 14, 2009, 02:17:21 PM »

Hi all!

Dennis T: I have made some measurements now and with the motor I have choosen its near impossible to use a front mount.

The Nobler ARF is not constructed the same way as a "real" Nobler. The cowling is made in the same way as on rc airplanes.

As have have made the decision to use a rear mounted engine I have now started to build a solid "box" to mount the motor to. The box will be 40mm x 40mm x 37mm (approx. 1.6" x 1.6" x 1.45"). Its constructed out of a 1/8" plywood plate to wich (sp?) the motor mount bolts to. The rest of the box is made up of balsa wood. This box will be glued to the firewall and 4 long hardened steel m3 bolts will go thru the motor mount, the box and the firewall. On the backside of the firewall there will be 4 blind nuts for the m3 bolts. This way, I hope to not experience the same problem as Alan did, as it should be nearly impossible for the engine to rip itself from the firewall (knock on wood.....) The box will also be wrapped in a layer of fibreglass.

Does anyone knows the thickness of the aluminum backplate of a GP 'E' spinner?

Andreas

William DeMauro · « **Reply #8 on:** May 14, 2009, 05:28:01 PM »

"Does anyone knows the thickness of the aluminum backplate of a GP 'E' spinner?"
I had a GP "E" spinner on my crashed E P40. In measuring what remains it is about 3/32 to 1/8 thick. It also appears to use the same backplate as the standard GP spinner as I compared it to a standard. The E spinner definitely uses a lighter cone and I bet thats the only difference. Good luck with your project!!!

andreas johansson · « **Reply #9 on:** May 15, 2009, 03:08:43 AM »

William: Thanks

Do you think I can grind away most part of the engine bearers in the tank (now battery) compartment? I'm thinking of grinding them flat with the "walls". Front of the firewall I will just cut them flat with the firewall.

Andreas

Dennis Adamisin · « **Reply #10 on:** May 15, 2009, 08:03:26 AM »

Quote from: Andreas on May 15, 2009, 03:08:43 AM

William: Thanks

Do you think I can grind away most part of the engine bearers in the tank (now battery) compartment? I'm thinking of grinding them flat with the "walls". Front of the firewall I will just cut them flat with the firewall.

Andreas

Andreas:
I agree you should remove the mounts, but there is a much better and easier way then grinding them down. See the pictures. Lat spring I converted an ARF to E-power and removed the mounts:

1. You have to separate the segment of the mount where it passes through the bulkheads. I have used a saw to to this or as shown in the picture I used a grinder here.

2. Drill two holes through the mount, and fit nails or stiff wire into the holes. These will be used as pry bars.

3. Using the pry bars, just pop the mount off - it might even scare you how easy it pops loose and how clean the separation is!

andreas johansson · « **Reply #11 on:** May 15, 2009, 08:49:00 AM »

Hi everyone!

Dennis A: Ooops, it IS actually a bit scary but I guess that crappy chinese ARF glue snaps loose like nothing. On the other hand, my glow Noblarf has been chrashed more than one time and the bearers still holds up..... but it could be due to the epoxy glue I used on them... Its a Vector you got there, right?

Well, now its time to go to the refrigerator and catch a beer, its Friday

and then some barbeque

Andreas

Alan Hahn · « **Reply #12 on:** May 15, 2009, 09:40:40 AM »

Quote from: Andreas on May 15, 2009, 03:08:43 AM

William: Thanks

Do you think I can grind away most part of the engine bearers in the tank (now battery) compartment? I'm thinking of grinding them flat with the "walls". Front of the firewall I will just cut them flat with the firewall.

Andreas

I glued a piece of light ply to the tank compartment bearers. First cut some slots in the light ply so that you can thread in two velcro tie straps. Now you have a nice way of holding the battery. I wouldn't obsess too much on the bearers--the Nober Arf is already very light, and you will in any case need something to hold the battery. This method works well for me.
Also I haven't had any issue with a firewall mount and the motor I use---which is the Scorpion 3020 (20mm length magnets). This is relatively short motor compared to the "26" versions a lot of people are using.

andreas johansson · « **Reply #13 on:** May 15, 2009, 11:38:41 AM »

Alan: You got a point there. I think I will copy your way of making a battery mount.

I have now used a dremel tool to cut of the engine bearers front of the firewall, it felt kinda strange to cut them off but now its done. Even if I had built it like a glow powered model I would have to cut them because they where warped in every direction front of the firewall

Do you think I can use two washers under the left side of the "X" motor mount to make the motor offset? It would be easier to do than to make the whole box lean outwards.

Andreas

andreas johansson · « **Reply #14 on:** May 15, 2009, 02:02:32 PM »

Just some pics.

Alan Hahn · « **Reply #15 on:** May 15, 2009, 05:36:25 PM »

Quote from: Andreas on May 15, 2009, 11:38:41 AM

....<snip>....

Do you think I can use two washers under the left side of the "X" motor mount to make the motor offset? It would be easier to do than to make the whole box lean outwards.

Andreas

Well that's what I do when I adjust the thrust line. You aren't adding any stresses to an engine crankcase like you would have with a glow setup. I would add some of the "soft" locktite adhesive on the mounting screws/blind nuts to keep things tight but easily removable.

andreas johansson · « **Reply #16 on:** May 16, 2009, 02:46:20 PM »

Alan: Thanks

I have finished the motor box this evening, it came out both strong and light. Its covered with som medium fibreglass cloth. I did use thin CA instead of epoxy on the fibreglass. I will need to grind away about 3/8 (10mm) of the engine bearers inside the battery compartment and glue some plywood in the openings for the engine bearers, this because two of the bolts for the motor will enter there and I need to put blind nuts there.

On a side note, I checked the wing and its straight as an arrow

Andreas

andreas johansson · « **Reply #17 on:** May 17, 2009, 12:18:08 PM »

Hi all

I hope you still are following this thread?

Today I have grinded away about 3/8"-1/2" of the bearers inside the battery compartment to make room for the blind nuts. I then made up som 1/8 plowood parts to glue in the openings in the firewall.
I also hade a strike of luck, it turns out that the firewall is glued in a bit off, its leaning outwards and if I glue the motor box a bit off center (to the left) I will get the right amount of motor offset and the spinner in the center of the cowling.

Andreas

andreas johansson · « **Reply #18 on:** May 18, 2009, 01:41:04 PM »

Hi all!

Today I have trial fitted the motor box, I first tried to center the box (and with the box the motor) with the lower line of the bearers. That way I should have the motor in the same line as a glow engine, but no matter how I tried I couldnt get a good cowl fit. The cowling always ended up with an enormous gap between the cowl and the top part of the fuselage. Then I remembered, on my glow Nobler ARF I had to add wood to the bearers to get a good cowl fit. So I lowered the box about 1/8 below the bearers and then the cowl did fit well.
Then I used the four holes in the box for the motor bolts as drill guides and drilled holes in the firewall for the blindnuts. Next thing to do will be to remove the box from the firewall and then enlarge the holes in the firewall and put the blindnuts in. When that is done I will epoxy the box to the firewall.

Andreas

Alan Hahn · « **Reply #19 on:** May 18, 2009, 02:31:31 PM »

I'm trying to remember what I did.

For some reason, I didn't need such a long motor box.
If you look back at my broken nose picture, you can see that I cut off the part of the cowl that extended back over the fuel tank/battery compartment. I then made up a balsa-equivalent cover that slides under the now-abbreviated cowl and uses a small button magnet to hold itself to the back of the compartment (near the landing gear). To remove the battery, my cowl tilts forward (I also use a 3-point magnet holding system for it), and I can slide out the battery cover and get access to the battery.

Here is a picture of my battery compartment showing how the battery is held in place. You can see the button magnet on the wing belly pan, just past the landing gear.

andreas johansson · « **Reply #20 on:** May 19, 2009, 12:25:09 AM »

Hi

I could probably used a somewhat shorter motor box, but I used the same distance from the firewall to the backplate of the spinner as stated in the manual.
As for the "battery cowl" I will use a similiar idea, I will cut the cowling where it extends back and glue wood in the fromt part of the battery cowl so that the wood acts like a "tongue" that passes under the motor cowling. As for locking the battery cowling in place magnets is a good idea, I might use that.

Andreas

andreas johansson · « **Reply #21 on:** May 19, 2009, 11:57:51 AM »

Hi

Got som time in my shop today too. I have now glued the motor box permanently to the firewall. I have mounted the four blind nuts to the backside of the firewall. As the firewall is pretty thin I cut of the small "pins" on the blindnuts and glued them into place.
I have also made a vertical support of 1/8 plywood that supports the motorbox on the under side. The support will also be used to mount the ESC.

As I dont have any lite ply at home (for the battery mount and some other small parts) and I cannot get any until sunday I will now start with the main wing. As there are plenty of "mod your Noblarf" threads I will not write about that here.

Andreas

andreas johansson · « **Reply #22 on:** May 21, 2009, 01:04:39 PM »

Alan: Are you using the stock landing gear or have you made a higher landing gear (you are using a 12" prop, right?)

Andreas

Alan Hahn · « **Reply #23 on:** May 22, 2009, 08:20:26 AM »

Andreas,
I did make some new gear plus put on large wheels too to get the ground clearance. Also put a larger tail wheel on to try and reduce the resulting large incidence. That of course makes the ground clearance a little worse.

Got to find out yesterday that I didn't use maple on the motor mount like I said. We were giving a demo flight at Marmion Academy to a teacher who wants to start a club there. The grass wasn't too bad, but was a bit thick. On my takeoff roll, I hit a bump or something and the prop dug in and the entire engine mount pulled off again. Discovered I used pine--it split one piece right down the center (along the grain).

Fortunately it is all glued back together this morning--only visible evidence (of this particular event) was a piece of the fiberglass cowl gell layer was dinged off. On top of course.

Probably need another 1/2 inch in gear height over what I already have!

andreas johansson · « **Reply #24 on:** May 22, 2009, 02:42:57 PM »

Thanks Alan. I guess I either have to buy a carbon gear (most probable) or make up a new one in real music wire, not the cheap crap that comes with the kit.
According to "murphys modellers law" your cowling will crack at its most visible part, and as you see the MM-law worked for you too (as it does to all of us). Well well, there are new cowlings available at Tower, I just received one from them (for my glow Nobler). I did a figure 7 from inverted flight (probably due to brain meltdown), fortunatly the ground was real soft.

btw, I have this Banshee kit in my shop, go electric?

Andreas

William DeMauro · « **Reply #25 on:** May 23, 2009, 03:25:19 AM »

btw, I have this Banshee kit in my shop, go electric?
Do it! My first electric was a Banshee.I converted it from wet power.Just watch how it balances as they do tend to be nose heavy. Mine was already shortened 1 1/2 inches for the wet setup and i was still nose heavy with the e-power. I will admit to using too much battery on it and a smaller lighter battery would have been better(4s 4000 was way too much). Maybe you can build it around the batteries you use in the Nobler.

andreas johansson · « **Reply #26 on:** May 23, 2009, 05:15:56 AM »

William,
Ok, If the Nobler works good I will use the same setup in the Banshee. I wont build the Banshee anytime soon, as my second child will be born any day now, but after the summer I hope I will have some time to build it.

Andreas

William DeMauro · « **Reply #27 on:** May 23, 2009, 06:36:35 AM »

Congratulations on the baby!!!! As you know they do take away from your building and flying time. When the eventually come out and fly with you it's the greatest feeling.My youngest (he's 12) is starting to learn to stunt now and its a great feeling to see him progress. Good luck with the Nobler I'm sure you will end up with a great flier!!

andreas johansson · « **Reply #28 on:** May 24, 2009, 10:37:03 AM »

Hi all!

William: Thanks

As for the Nobler, I have now made a battery mount out of a 1/8" light plywood sheet. I just made a plate that fits in the tank compartment and cut out som slits in it för the Velcro. I then glued it to the engine bearers.
I also made a small plate for mounting the ESC to.

Andreas

Edit: I know that it looks like the motor is leaning downwards in the picture, but in reality its straight.

Crist Rigotti · « **Reply #29 on:** May 24, 2009, 12:47:36 PM »

Looking good. I'm enjoying the pictures of your progress.

Mike Anderson · « **Reply #30 on:** May 24, 2009, 05:42:59 PM »

Quote from: Andreas on May 24, 2009, 10:37:03 AM

Hi all!

Edit: I know that it looks like the motor is leaning downwards in the picture, but in reality its straight.

Actually, it looks to me like your wall is leaning to the right -

andreas johansson · « **Reply #31 on:** May 29, 2009, 01:31:50 PM »

Hi all!

Its been a while since I updated this thread, so here is a status update:

Mainly I have done assembly to the non-electrical part of the aircraft. However, I do have soldered connectors to the ESC. I have also included an arming plug in the ESC setup in the same way as Alan did.
I´m waiting for the batteries I have ordered so I can test the motor.

Andreas

Alan Hahn · « **Reply #32 on:** May 29, 2009, 03:51:56 PM »

Quote from: Andreas on May 29, 2009, 01:31:50 PM

Hi all!

Its been a while since I updated this thread, so here is a status update:

Mainly I have done assembly to the non-electrical part of the aircraft. However, I do have soldered connectors to the ESC. I have also included an arming plug in the ESC setup in the same way as Alan did.
I´m waiting for the batteries I have ordered so I can test the motor.

Andreas

Andreas,
I don't recall how much of this electric stuff you have already done, but if this is the first time, here are a few cautions.

1) Charge up the batteries before testing anything. They are shipped at partial charges, and if you hook one up right away and run it, it is possible to over-discharge it. That can damage the battery.
2) For full up static throttle runs, use a smaller prop. You can really heat up everything with the normal prop.
3) Be careful. These darn electric motors are almost always alive and ready to go-very different that a glow setup. Ask me how I know that (it involves a short test flight from my Easy Boy chair in the basement into my Entertainment center.)

andreas johansson · « **Reply #33 on:** May 30, 2009, 04:39:30 AM »

Alan,

I got some experience of LIPO batterys, I use them as transmitter and receiver batterys in my rc pattern planes and helicopters. I do not have any experience with high drain systems thou. I will follow your recommendations (as usual

).

Andreas

John Cralley · « **Reply #34 on:** May 30, 2009, 08:05:58 AM »

Quote from: Alan Hahn on May 29, 2009, 03:51:56 PM

3) Be careful. These darn electric motors are almost always alive and ready to go-very different that a glow setup. Ask me how I know that (it involves a short test flight from my Easy Boy chair in the basement into my Entertainment center.)

Humm, I've been there as well. My latest involved a full power/full prop test run in Richard Oliver's workshop at the recent Ringmaster Roundup. I managed to suck a 2 to 3 foot sheet of butcher paper into the prop and made confetti! Scared the daylights out of me but luckily no harm was done just a mess to clean up.

John Witt · « **Reply #35 on:** June 03, 2009, 08:12:22 PM »

Those sound like stories for the Amazing Model Stories thread.

John Witt

andreas johansson · « **Reply #36 on:** June 04, 2009, 11:51:48 AM »

Hi all!

I tested the electric system yesterday. This thing gonna haul

The motor was very powerful, I did run it at 8500 rpms with a 11x5.5 prop (just for a short while). I also noted that these motors are dangerous, at one time I tried to reposition the model and the prop did strike the lawn ground pretty hard (it would almost certanly killed a glow engine) and the thing just did a nice clean cut in the ground. I do not want my fingers anywhere near this motor/prop when its running.

Andreas

andreas johansson · « **Reply #37 on:** June 21, 2009, 08:53:54 AM »

Hi

Its been some time since I last wrote anything about my E-Noblarf. Today I finished the plane (mounted a new landing gear made of real music wire and about an inch taller than the stock ones). The all up weight ready for flight (with battery) is 45 oz.

Andreas

Dennis Adamisin · « **Reply #38 on:** June 22, 2009, 06:46:28 AM »

CONGRATS!

45 oz Nobler with a strong power system is a formidable package - this one will serve you well!

andreas johansson · « **Reply #39 on:** June 22, 2009, 07:22:00 AM »

Hi

Wednesday morning this week is scheduled for test flight of the E-Noblarf.

btw, I bought an issue of the German magazine FMT. It contained a full size plan for Claus Maikis electric profile ME-109. A very nice construction in similiar size of a Nobler.

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

Andreas

andreas johansson · « **Reply #40 on:** June 24, 2009, 02:16:17 AM »

Hi all.

Well, now its time to "end" this thread. I have flown my E-Noblarf today and it worked perfectly. About 5 seconds / lap and very good line tension. I'm using a 12x8 prop and just above 8000 rpm.

Andreas

Alan Hahn · « **Reply #41 on:** June 24, 2009, 07:47:58 AM »

Andreas,
Congratulations!

But before you close out the thread, please give us a detail of your setup in the "List your Setup" sticky at the top of the electric forum!

Here is the link

http://stunthanger.com/smf/index.php?topic=12044.0

andreas johansson · « **Reply #42 on:** June 24, 2009, 10:26:07 AM »

I have now listed my setup.

I would like to thank everyone who has contributed to this thread. You have helped me to see the "silent light", and it feels like I have built my last glow powered model. Electric models are the future and its no idea to fight against it. One of many positive things about E-CL: after my last flight today I just put my model in my car, no paper towels, no oily surfaces!

I would also like to send a special thanks to Mr. Alan Hahn, you have been there and answered my questions all the time.

Next model will be an electric powered Banshee (the kit is surfing around in my shop), it will be a build thread about the Banshee too.

/Andreas