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Discussion Starter · #1 ·
Figures, just ordered one of Doug’s Slick kits and now I found a used Mojo 40 locally. I’m picking it up next Monday. It’s set up for glow with an OS 46fx, but I’m going to convert it to electric, as I have been over the slimers foe years. I have a nib VH G32-800kv and a ZTX 85A ESC/5A BEC. What 4s battery mAH would be a good match, 2200,2500,3000,3300 or higher?
 

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Discussion Starter · #4 ·
Thanks for the info. I guess I should weigh it before and after I remove the glow stuff and throttle servo. It looks like they dolled it up with some extra trim covering so that added some weight also. I was going to go with a 46 size motor, but had good luck in the past with the G32 on a VH Sabre ARF.
 

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Discussion Starter · #10 ·
You dont sound happy,give that mojo some love,fly it hard while you build that slick. Might save your slick a few bumps while getting them fingers ready. Bet you ant got much money in that mojo,time to,how can you beat that. Best to have backup planes,never know when a ut oo turns to oh no,get the bag.
I’m very happy to have a Mojo again! I plan to wear it out, or the ground will :). I still haven’t learned how to do rolling harriers and circles, so that’s on my radar. I had been looking for a new or used 40 size balsa profile for months and gave up. Then Soug decided to make some kits up and i I was happy to order one, I haven’t built a kit since a Sweet Stik and Super Sportster back in the 80’s, should be fun!
 

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Discussion Starter · #11 ·
Well I went ahead and bought the Mojo 40 but the downside is that it was one of them with detachable wing kits (In hind sight you can make out the screw tabs on the back of the wing in the pic, I missed it). I’m assuming it will be a little weaker and heavier. I weighed it as is with the FX46 and empty fuel tank (minus fuel and Rx battery). It was around 3.8-4 lbs., so I’m guessing it would be about 4-1/2 lbs. or slightly more when flying. He said it hovered find, but was slow on pullout. He suggested an AX55 or Saito 72. Since I’m going to convert it to E-power, so you think the G32 will be enough power at these weights?
 

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Discussion Starter · #13 ·
I knew the carbon fiber would be stronger, is it lighter than aluminum? Just remove the fuse covering and epoxy the wings to it? Nothing else needed?
 

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Discussion Starter · #18 ·
I weighted parts for comparison and converting to e-power is 8oz. less weight.

FX46 w/prop and muffler. 18.4
8oz. Tank, fuel 9.0
Rx battery, Thr. servo, switch. 7.0
34.4 oz.

G32 Motor, Mount, prop 10.4
ESC 85A. 2.0
4s-3300 Lipo. 13.8
26.2 oz.

The aluminum tube 1/2”x24”. 1.8 oz.

Adding in epoxy for the gluing in the wings, I should still be at 4.5lbs. or a bit less. I’m not sure it’s worth replacing the tube with CF, since the aluminum tube only weighs 1.8 ozs.

What do you Bros think?
 

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Discussion Starter · #20 ·
Found an old cf 1/2” tube a buddy had in his stash, he saved me $45. Glued the wings on today with the GG as suggested. Mounted the G32 and tested the cg with a Gens Ace 4s-3300 right behind the motor and I’m pretty tail heavy, about 6-6.5”. I have the motor at the rear of the cutout. I’m thinking I need to move it forward an inch or more. Any issues with mounting it further out inside the jaws? Right now the prop just clears the end of the fuse. Also, what brand of Lipos do you Bro’s like to use these days?
 

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Discussion Starter · #24 ·
Nice work (y)
4.5 lb isn't terrible for a 40 slab. I revitalized the famous Gator Skin Chakk last summer and it came out a couple of oz. heavier than that and everyone still had a blast with it at last years Ottumwa ProBro. :):)
For Lipo batteries, some people think Thunder Power is overpriced for what you get, but I really like them and I buy all mine on the 50% off black Friday sale they have every year. The sale the price is comparable to all other brands pricing. All my batts in the last 5 year have been Thunder Power and they're light and perform great for me.
I used some Hobby King Zippy compact batts for a project a few years back also because they were the only ones that had that size in the MAH I wanted so I tried 6 of them and they are working great also, but I go easy on my batteries!!
Thanks, I’ll be looking for TT Lipos sales on Black Friday. I just placed an order for some Glacier Lipos. I’ve used them in the past and they seemed on par with GenAce.
 

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Discussion Starter · #25 · (Edited)
I’m thinking 13-4 props for the G32 on 4s, but I think Gus recommended a 14-7. Wouldn’t a 4 pitch have more pull, but slower flight? Do you all like APC, or wooden e-props?
 

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Discussion Starter · #28 ·
McDDD, Yep, it’s been awhile since I’ve gone through all this stuff. I had it all ass backwards, thanks for pointing that out to me.
Lower pitch gives you less speed, and larger prop gives you more thrust. In the case of the G32 on 4s, I guess I’ll try a 14x5 and 14-6 that I have on hand and use a watt meter to see how how many amps and watts I’m getting. I expect it to be high. I only have a 85A ESC so I don’t want to over load it or the motor.
 

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Discussion Starter · #29 ·
For e-power are you all using wood props (I have a 14-6 xoar, and a 14-5 jxf), or do you use apc-e props (13-4 is the largest I have on hand)?
 

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Discussion Starter · #32 ·
Thanks Spark plug, I already moved the motor from the rear of the jaws to the front. I can now balance the cg at 4.5” and move it back once I get used to how it flys. I think it’s a little tail heavy due to the full size servos in it and my e-setup weighs less then the glow setup that was on it. I may fill in the jaws behind the motor with balsa so I have more area to Velcro the battery on. I was initially thinking 3s, but the Mojo is on the porky side compared to Doug’s Slick design. So I’m going with 4s since most folks on here recommended that setup.
 

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Discussion Starter · #35 ·
I’d move the engine out as far as you need to along with the esc and lipo to get the cg before I added weight but I wouldn’t have the mount any closer to the tip of the nose than 1/2”. That’s just my personal thought. I’d rather use stand offs/spacers to get the motor pushed out a little rather than move the mount way out on the end of the nose.
But moving the motor out that far has a negative effect in that it basically adds to the nose moment (the length from center of lift to the prop). A longer nose moment will detract from pitch authority as well as rudder authority when tumbling and pinwheels and such. But so would a chunk of lead hung way out on the nose.
The good news is you shouldn’t need to move it out too far on a mojo. They CG pretty good even electric. Mine always did, anyway.
If it was built heavy in tbe tail or the servos are on the heavy side I’d say it’s worth it to move the tail servos up one bay rather than add weight or push the motor forward too far. It’s almost a requirement on a primo.

As far as lipo brands go, I’ve had the most luck and consistency over the years with the regular blue label hobbyking lipos. Recently I’ve tried some Admiral brand pack from motionrc and I’ve been impressed so far. But time will tell how they hold up.
Thanks for the good info. I have already moved the motor forward. The mount is exacty 1/2” from the front of the nose and puts the back of the prop 1-3/4” in front of the nose vs. about 1/2” where I previously had it mounted. I’ll look into moving the tail servos if I’m not happy with the way it flys.
 

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Discussion Starter · #38 ·
Never satisfied with electric, what didn’t you like, the length short flight times? If mine flys 1/2 as good as yours I’ll be a happy camper. My old ass thumbs will never be able to keep up with most of the ProBros here. Great flying my friend!
 

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Discussion Starter · #41 ·
Thanks for the good info. I have already moved the motor forward. The mount is exacty 1/2” from the front of the nose and puts the back of the prop 1-3/4” in front of the nose vs. about 1/2” where I previously had it mounted. I’ll look into moving the tail servos if I’m not happy with the way it flys.
I’d move the engine out as far as you need to along with the esc and lipo to get the cg before I added weight but I wouldn’t have the mount any closer to the tip of the nose than 1/2”. That’s just my personal thought. I’d rather use stand offs/spacers to get the motor pushed out a little rather than move the mount way out on the end of the nose.
But moving the motor out that far has a negative effect in that it basically adds to the nose moment (the length from center of lift to the prop). A longer nose moment will detract from pitch authority as well as rudder authority when tumbling and pinwheels and such. But so would a chunk of lead hung way out on the nose.
The good news is you shouldn’t need to move it out too far on a mojo. They CG pretty good even electric. Mine always did, anyway.
If it was built heavy in tbe tail or the servos are on the heavy side I’d say it’s worth it to move the tail servos up one bay rather than add weight or push the motor forward too far. It’s almost a requirement on a primo.

As far as lipo brands go, I’ve had the most luck and consistency over the years with the regular blue label hobbyking lipos. Recently I’ve tried some Admiral brand pack from motionrc and I’ve been impressed so far. But time will tell how they hold up.
I’d move the engine out as far as you need to along with the esc and lipo to get the cg before I added weight but I wouldn’t have the mount any closer to the tip of the nose than 1/2”. That’s just my personal thought. I’d rather use stand offs/spacers to get the motor pushed out a little rather than move the mount way out on the end of the nose.
But moving the motor out that far has a negative effect in that it basically adds to the nose moment (the length from center of lift to the prop). A longer nose moment will detract from pitch authority as well as rudder authority when tumbling and pinwheels and such. But so would a chunk of lead hung way out on the nose.
The good news is you shouldn’t need to move it out too far on a mojo. They CG pretty good even electric. Mine always did, anyway.
If it was built heavy in tbe tail or the servos are on the heavy side I’d say it’s worth it to move the tail servos up one bay rather than add weight or push the motor forward too far. It’s almost a requirement on a primo.

As far as lipo brands go, I’ve had the most luck and consistency over the years with the regular blue label hobbyking lipos. Recently I’ve tried some Admiral brand pack from motionrc and I’ve been impressed so far. But time will tell how they hold up.
To your wood or plastic propeller question on E props, I'm using plastic or composite for 13 inch or under. For E props larger than that, I highly recommend staying with the wood props, as the plastic ones get flexy and can cavitate. I like Xoar, Sail or even the Hobby King E wood ones are working good for me.
I’ll have to find some 14-6 E props, I only have Xoar gas props in that size. I’ll start out with a 14-5 cheap E-prop and see how it pulls. Here is a pic of the motor moves out to balance the cg, kind of fugly. We shall see!
 

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Discussion Starter · #44 ·
Gregory, that motor is out to the max imho. Pull that CG right up behind it and put the lipo on the opposite side.
And E props are a must. I like xoar and falcon. Falcon respond better imho. I’ve become a falcon fan on gas too. Just my 2cents.
Thanks for the suggestions. I’ll give it a try next week, If I don’t like the way it pulls, I’ll look at new more compact servos and/or possible moving them back a bay. Since i glued the wings on, I hope there is enough wire to solder the new servos from the tail side. Tough finding Falcon or that matter 14-6 E-props. I’ll check with a local hobby shop and see if they have any. Maiden will be with the 14-5 that’s on it in the picture. Charging a Lipo now to see who many amps that prop pulls, and then I start to button it all up.
 
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