mludwin

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I'm pulling out the good ol' Super Sportster 60 and going electric. I've got a Axi4130/20 w/ a Jeti 77 enough 4cell/4000mAh lipos to make a 8s1p or 8s2p with. But don't have clue for porp size. Any thought's??

jonnyjetprop

My Feedback: (3)

Here's the manufacture's website: http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_41&id_produktu=axi_4130_20&nazev_rady=Series%20AXI%2041%20GOLD%20LINE&hmotnost_rady=(320%20-%20409%20g)

It looks like a 16x10. I'd prop it for 40 amps at full throttle. Other props would be 15x10 or 15x12.

John

mludwin

My Feedback: (3)

Hey John, thanks for the reply. It looks like I'll be building up my e-prop collection to match the wood collection I already have. I had a friend recomend a 15x10 also. Electrics sure have a learning curve. I guess there's no other way of figuring things out until I try them.

Marty

mludwin

My Feedback: (3)

Got started last night.

This kit is about 17years old and it's about 7 years since I've flown it. I had an Irvine .61 with a tuned pipe in it and it flew great.

First lucky break was the motor mount holes matched exactly to the Axi adapter plate. It look like I going to have to extend the mount an 1 /12" from the main bulkhead. Not sure how yet. I also have to carve out clearance for the motor and allow for airflow.

mludwin

My Feedback: (3)

Have clearance now. Extending the motor mount? I'm thinking of nylon spacers with 8/32 bolts. I have seen others use this method, but I'm not sure if they'll hold a Axi 4130 in place.

I'm also thinking of sliding the ESC in from the front and attaching it with velco to the top side of the old tank area.

Any feedback will be helpful.

algutkin

My Feedback: (1)

I came up with a solution that is better than the nylon spacers and has worked for me.

Since the distance isn't that much, I built a wood box, made out of 1/4 inch oak or poplar bought at Home Depot, to be used as a spacer. This spacer box goes between the radial mount and the existing firewall. The box also serves to reinforce the firewall and engine mounting. The box is glued with epoxy but you don't have to worry about it breaking, there is no stress.

Measure and make the box slightly larger than the radial mount.

Use the radial mount as a template and drill the holes all the way through the box, to match the blind nuts and holes in the firewall. The object is to put long screws through the radial mount, through the box into the existing holes in the firewall with blind nuts behind.

I used a similar method on all of my Hangar 9 conversions. I am uploading a picture, however I had quite a distance to make up so I could not use the radial mount.

mludwin

My Feedback: (3)

I get it. This I can do with scrap I have on hand. As soon as have the motor in I can figure out CG and place the batteries

mludwin

My Feedback: (3)

Have the motor mounted using the idea from algutkin, Thanks!

I'm now ready to install batteries and wire things up. The location in the pic is where the CG fell. I'm thinking of using velcro straps for hold things in place.

mludwin

My Feedback: (3)

All together with batteries and motor 11lbs. I have a 16x10 APC e-prop on it. I won't be able to roll down the field with this prop unless I go to much larger wheels. 3 1/4" are on it in the pic.

I guess this is where I start learning about prop sizes for electric motors. Any help here will be greatly appreciated.

ray foley

You will want to bend up a new set of landing gears for enhanced prop clearance. At that weight, use 3/16" piano wire from your LHS. You will also have to drill out the wheels for 3/16"+ to match the LG dia. The LG blocks in your wing will also need to be drilled out to 3/16". All the above is pretty easy. If perplexed, ask around you club, help will be found easily.

ciao -rjf

ps: the 16x10 Eprop should be just aqbout right for that motor. -r

pps: Also consider removing the spinner and substituting a Dubro spinner nut, M8x1, for enhanced airflow to the motor. The original spinner will block th airflow to the AXI too much, trust me on this one, really. -rjf

ray foley

About the previous post, I realize that the spinner nut will change the lines of the Sportster a bit but the cooling issue at elevated power levels can be critical. With the spinner nut the motor will run cool to slightly warm, with the full dia spinner blocking the air inlets to the AXI, it will run hot and may let out the magic smoke. The magic smoke is very hard to collect and put back into the motor.

So let a word to the wise prevail. Wanna guess how I know?

Sadder but wiser -rjf

mludwin

My Feedback: (3)

Thanks for the input Ray. I added 1" to the LG and this gives me 3/4" clearance to the ground with the tail high. Next will be changing out the spinner, I hadn't thought of that. I really should say thanks for saving my motor & $$$$

I'm waitng to borrow a buddy's whatt meter to check current draw and I should be set for a maiden flight with the new power plant.

mludwin

My Feedback: (3)

Maiden flight today and a beautiful day it was. I ended up trying 3 props with a whatt meter

16x10 45 amps
15x10 37 amps
15x 8 32 amps

I flew with the 15x10 (no spinner, thanks ray) and at 1/2 throttle it jumped into the air. The kit flew great as I always remebering it did. I use to fly this kit with a Irvine .60 with a tuned pipe. The Axi power plant had more than enought power to make it feel the same. Approaches were a little hot at first but by the 3rd attempt it had it under control. I landed after about 6 minutes of flight time and I still had 30volts in the packs. (32v when I started) 10 minute flights should be no problem.

Now I have to wait until next weekend to fly again [:-]

Super Sportster 60, built in 1989

Axi 4130/20
Jeti 77
Skyshark 4000mAh 4c lipo 2 packs in series for a 8S1P

ray foley

I think the approaches were "a little hot" due in part to the lack of engine head and muffler sticking out into the wind causing drag. E-power planes are somewhat slipperier than their slimer counterparts.

Also you are used to the C/G shifting backward as fuel is consumed with a slimer. This does not happen with E-power. So try balancing the plane a little more aft, 1/4" to 1/2" rearward should do just fine.

Sportsters are great!!! -rjf

mludwin

My Feedback: (3)

I hear ya Ray,

For my next flight I have the CG setup at factory location @ 3 1/4" with a 2 oz propnut. Hoping then I can switch to a 1oz or plain nut qucikly in the field to move the CG back.

Now we need some nice weather out here, everything is soaked.

hhheagle

MLudwin:

How well do the Skyshark Lipos perform? Do you use their balancing charger ???

mludwin

My Feedback: (3)

With only a few flights on the lipo's it's tough to say. But judging from the quality of other Skyshark products I have, I am happy.

I use a Astro 109s and blinky(s)