I have this Kadet Mark II that I would like to convert to electric.
I am going to use an AXI2826/12 and Jeti 40plus ESC

As you can see in the last photo the glow engine I had in it is much further out from the firewall than the electric will be. I would like to continue using the cowl if I can, so how can I adjust the electric motor installation so that it is equal to where the glow engine is?

P.S: I would like this solution to be removable in case later I want to convert it back to the glow. -

Stand offs

It appears you do not have far to move it out You could just use a block of wood at least the diameter of the motor mount drilled for the bolts and use long bolts from the hardware store to blind muts in the firewall

Another way to do a stand off is use lamp tubes from the lighting department (for making, repairing lamps) just cut them to length and agine use long bolts. I done this method quite a few times. Another material you could use for the stand off tubes is copper tubing and easy to work with, this works well with the short distances you are working with.

At any rate you will have to drill the firewall and install blind nuts for the electric mount and just leave the existing blind nuts in tact.

John

Thank you. You have any graphics available to show how to do?

Can,t help with grafiics. Visulize your motor mount bolted to the firewall as intended but now you used longer bolts throught the mount and firewall and you placed four tubes or a drilled block of wood between the mount and the firewall the thickness of these 'standoffs' is the distance you want to extend the motor forward. The long bolts pass through the motor mount then the tubes or block of wood and finally the firewall.

John

Got it, thank you so much.

Here's a picture of the motor mount on my Modeltech Magic. I just kept adding longer bolts and spacers until I got the CG right. The spacers are in a drawer at Ace Hardware.

I'm currently reviewing the Electrifly Sopwith Camel and it uses the same method to position the motor. All you need it 3 blind nuts (for behind the firewall), 3 machine screws, 3 flat washers, and 3 pieces of aluminum tubing. Cut the tubing to the length you need to properly position the motor and feed the screws through the mount on the motor. Slip the tubing over each screw and then through a flat washer. Then screw those through the firewall into the blind nuts on the backside of the firewall. It would help to put threadlock on the screws to keep them secure.

Ken

Thank you. I think it would be easier to find nylon spacers in my local hardware store, would they be good or would the aluminum be best?

You could do it either way, but depending on how far out you need to mount it you might not be able to find nylon spacers that long. The aluminum tube is easier to find, you can cut it to length, and is lighter than the nylon spacers are.

Ken

I measured the distance and I need 1 1/4" long spacers X I figure about 1/2" diameter. And M3 bolts about 1 1/2" - 1 3/4" long. And my motor mount has 4 mounting holes.

The attached pics is the hole I drilled below the fuel-line opening to pass the ESC through.

Then use 4 bolts instead of 3 if that's what you need for your motor.

Ken

BATTERY QUESTION:

I know that NiMH batteries are not as good as Lipo, but out of these three batteries which is best for this motor and plane?

NiMH batteries - more affordable:
http://www3.towerhobbies.com/cgi-bin...?&I=LA3017&P=1
http://www3.towerhobbies.com/cgi-bin...?&I=LA3020&P=1
http://www3.towerhobbies.com/cgi-bin...?&I=LA3020&P=1

The first one I have one of those and it does run the motor but would one of the other two be better?

No do not use tubing type standoffs a half inch diameter. Yes of course since your mount is a four bolt type you would use four stand offs but they only need to be of sufficient diameter to allow the bolt pass through. Agine they can be made of almost any rigid type tubing. that your bolts, what maybe #6 will just pass through.


John

OK will get smaller diameter. Now what about question in post #12?

You really don't want to go with NiMh batteries. You can get so much more power for the same weight with LiPo's. I don't know what size you are looking at, but this one is about the same capacity as the first battery in your list, at the same price and about half the weight:

http://www.hobbycity.com/hobbycity/s...0C_Lipoly_Pack

I assume that you want something bigger than this for your Kadet, but I have several of these batteries, and they work great. I get 6-8 minute flights on the Magic using this motor and a 45A ESC.

http://www.hobbycity.com/hobbycity/s...idProduct=3887

The all up weight of that plane is about 3 1/4 pounds. I suspect your Kadet is a bit heavier.

Good luck.

OK let's ask you fine folks. How is the battery pack mclina mentioned above compared to the battery packs I mentioned? Good enough for a Kadet? What power should I get if I want more than 6 minutes, let's say 15?

What does that plane weigh? The weight must include the motor, ESC, battery, and servos as well as the fuselage as you would fly it.

The 40 amp ESC does not seem like enough for the Kadet Mk II, but I could be mistaken.

As a rule of thumb, the input power for a sports plane should be about 110 W/kg (50 W/lb) in order to get reasonable flying characteristics. Gliders and parkflyers may need much less power, 65 W/kg (30 W/lb), while the scale and aerobatics may need much more power, e.g. > 200 W/kg (90 W/lb). This assuming that the motor has about 75% efficiency.

There is more to it than that, but this information should guide you for your selection of the motor for this conversion.

Here is the AXI 2826/12 motor I own
http://www3.towerhobbies.com/cgi-bin...?&I=LXPPX7&P=0
Designed for models up to 3.3 - 6.6lb (1500 - 3000g)

Here is another link for the motor I have
http://www.hobby-lobby.com/brushless-axi2826.htm

Stated: More powerful motor replacement for .40 and .46 size glow powered airplanes.
Sells as combo with 40amp ESC

The Mark II is a .25-.40 size kit, flying weight around 5 lbs, so according to these sites the motor is more than enough.

Thank you all for your advice, greatly appreciated. I am doing my homework.

John, I would be careful here as the Animal Rights Activist may jump on you for this. I too am a fan of utilizing "blind muts" but it should not be put in an open forum

Another standoff option is plastic pipe; one piece which fits just inside the three or four mounting bolts. I use pcs of 4-40 full threaded rod if I can't get screws/bolts long enough. I have found the plastic tailpipe for sink drains to be a handy size for motors like AXI 2820 or so & it's the right wall thickness too.

I would agree with CGR, that 40A esc does seem a bit small. Just for comparison, my motor is smaller than yours, and my plane is at least 1 pound lighter, and my 45 amp ESC gets pretty warm during flight. (I don't have an amp meter) My plane is a 3D plane, but I do not fly it like one. I just fly around and do mild acrobatics. I will do a few short full throttle vertical bursts in a normal flight, but it's mostly 1/2 throttle or less.

This seems like a bad comparison to me.

Your motor is smaller than mine, plane is a pound smaller, and your ESC is 5 amps more than mine. That is why your ESC is getting warm, it is way too big for your motor and plane. Why would you have a 45amp ESC in a motor and plane that is smaller than mine, when mine recommends only a 40amp? Sounds to me like yours should be something around 30-35 amps. It's simple that you are using too many amps for a small motor and causing it to get hot.

This is the setup that is recommended by AXI, so I will stick by it. It cost me over $200 for this setup and I can not afford to do a large purchase like this again. Like it states by AXI the motor I have replaces a 40-46 size glow engine, and is good for planes up to 6 lbs.

I only have to find a suitable battery for this setup. I am not getting a response to post #12 so I will have to go by trial and error.

This is incorrect. Amps are the amount of power that is being drawn. An ESC rated for 45 amps means that is can handle a MAXIMUM power draw of 45 amps. It does not mean that it is PUSHING 45 amps through a motor.

Ken

OK, I am wrong. And it is probably true I would be better off getting a 45amp, but I just can not afford another $115 or so. But the 40amp must work enough or AXI wouldn't recommend it.

List price of the ESC you showed above - $99.90 [link]http://www.hobby-lobby.com/jetiblue.htm[/link]

Great Planes Silver Series 45A Brushless ESC - $59.99 [link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKSY6&P=ML[/link]

GWS 45 amp brushelss esc - $60.00 -[link]http://www.bphobbies.com/view.asp?id=A0780192&pid=B3965436[/link]

Castle Creations Brushless 45A ESC - $101.96 [link]http://www.bphobbies.com/view.asp?id=A0780192&pid=U941640[/link]

Ken