Hi there. I have just purchased a hextronik 24g 1500kv motor for my ms composit mini swift. I have the mini swift frame but I know I Won't be able to use the suggested 8" prop. Will the this motor be under powered using a 450mah 3s battery and a 5x5 APC prop? I could use a mini quad motor but I quite fancy the idea of having a prop saver. My friend has the larger MS composite wing and uses 6" gem fan props but it's 50/50 if they break on landing. If the prop is facing down it will either break or bend. I could of went with the 3000kv motor but it only supports 2s. I only have 3s batteries to use and want to keep the cost down.
Hextronik 24g 1500kv with a 5x5 prop on a <250g flying wing.
- Thread starter vector25
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The 3s and 5x5 props should work ok on that motor, but it might be a good idea run it for a while at 70% throttle make sure the ESC doesn't get too warm.
I bought one of these motors would love to give you some bench testing info, but unfortunately it was dead on arrival and I'm stuck in week 2 of Hobby King return purgatory.
I bought one of these motors would love to give you some bench testing info, but unfortunately it was dead on arrival and I'm stuck in week 2 of Hobby King return purgatory.
I will be using my old 12A emax ESCS I first bought for my mini quad. I have 2 left which will never get used. I think these should be fine.
Another question I have is. If I drill out the hole on a gemfan 5045 prop to fit the prop saver. Would that upset the balance of the prop in a major way or would I still be able to fix it?
Another question I have is. If I drill out the hole on a gemfan 5045 prop to fit the prop saver. Would that upset the balance of the prop in a major way or would I still be able to fix it?
That should work just fine - opening up the props to fit the prop saver is something I do on a regular basis. Haven't had any problems with being able to rebalance them afterwards. I use a tapered hand reamer similar to this one, but drilling should work just fine too.
http://www.rcplanebuilder.com/tools/prop-reamer-tapered-1-8-1-2
http://www.rcplanebuilder.com/tools/prop-reamer-tapered-1-8-1-2
Thanks for the help! I will wait till I get the motor before deciding what props to use. I have weighed the plane up minus the motor/prop and it comes to 110g. I assume the motor +bullet connectors + prop will weigh around 25-35g so total weight should be well under 200g, which makes me less worried about being under powered. Hopefully it should be a little easier to fly over my heavier 240g one.
Bayboos
Active member
I'm using 24g hexTronik 1300kv on my FT 3D PRO (220g AUW) with 9x4,7 prop and 3s battery. The 12A ESC from HobbyKing is barely warm. I was using the same motor on my Storch, and never had any problems; even after 30min+ flights.
I also use 24g 1700kv on a 300g profile "cartoon biplane" with 8x4 prop. With 2s battery the ESC (again, 12A) gets noticeably warm, but nothing else.
Both "measurements" taken after aerobatic flights, including a lot of hovering (or at least hovering attempts). I never had the 1500kv version; but I bet you will be safe with 12A ESC and 5x5 prop. The thrust is a whole different story. I have no problems pulling more than 300g of static thrust in both cases; but that might not be true for the prop that is 3 inches smaller. On the other hand, 5x5 prop may perform better in high speed flight (none of my 24g powered planes fly fast by any means).
I also use 24g 1700kv on a 300g profile "cartoon biplane" with 8x4 prop. With 2s battery the ESC (again, 12A) gets noticeably warm, but nothing else.
Both "measurements" taken after aerobatic flights, including a lot of hovering (or at least hovering attempts). I never had the 1500kv version; but I bet you will be safe with 12A ESC and 5x5 prop. The thrust is a whole different story. I have no problems pulling more than 300g of static thrust in both cases; but that might not be true for the prop that is 3 inches smaller. On the other hand, 5x5 prop may perform better in high speed flight (none of my 24g powered planes fly fast by any means).
Thanks for the info! I'm not looking for a fast flier. It's just something I can just cruise with and give other people a chance to fly. The thrust ratings when using 8inch props are kind of useless to me since the mini swift can only support up to 5 inch props. I'm hoping the pitch on the 5x5 APC prop will help give it some extra speed it needs.
I received my motor and installed it. After a few throws I realized that it has no power and as soon as you give it throttle, it just rotates widly. Just holding it and giving it a quick burst of throttle you can feel it's under powered. It doesn't want to lift a 170g wing 
I might try the 3000kv version but I don't know if that will solve the rotating issue.
I might try the 3000kv version but I don't know if that will solve the rotating issue.m00ndancer
Member
I received my motor and installed it. After a few throws I realized that it has no power and as soon as you give it throttle, it just rotates widly. Just holding it and giving it a quick burst of throttle you can feel it's under powered. It doesn't want to lift a 170g wing
the 3000kv motor is a beast with 3S, but you need a smaller prop (5x3/4.5x4.5/4.75x4.75)
But the rotating issue I don't understand...
There is a user that have done some tests:
4,1x4,1 2s/9,28A/70W 3s/17A/189W
4,5x4,1 2s/11A/84W 3s/20A/225W
4,5x4,5 2s/12A/93W 3s/22A/238W
4,7x4,25 2s/12A/89W 3s/22A/241W
4,75x4,75 2s/13,6A/102W 3s/24A/262W
4,75x5,50 2s/15,8A/116W
5x5 2s/14,8A/110W
5x5 Large 2s/16,7A/122W
5,1x4,5 Large 2s/17,8A/130W
5,25x4,75 2s/17A/124W
5,25x6,25 2s/20,7A/148W
5,5x4,5 2s/16,7A/122W
6x4 2s/20A/156W
6x5 2s/19A/150W
6x5,5 2s/23A/180W
Motor is tight in the bracket. I replaced the two screws (forgot the real name of them) that hold the motor in the bracket with pointy ones so it gets a better grip.
The rotating issue is, when throw it over head so you get a good clean flat glide, as soon as you start giving it throttle the whole wing will rotate anti clockwise (looking from behind). If you just give it full throttle it will just turn anti clockwise and nose dive straight to the ground really quickly.
Thanks for that! The only reason I went with the 1500kv motor is because it said clearly, it supported 3S. I knew from reading around the 3000kv worked with 3s but I've listened to people before and have had motors burn out. Unless it officially says on the product page that it supports it, I tend to stay away! I hate having to return items. If I went with the 3000kv, I would have to change my ESC.
Ahh - that makes sense. Overcoming the propellor inertia at low airspeed is causing the whole body to rotate before enough airflow is going over the wing to apply counter pressure.
I can see the problem, but I don't have enough experience with wings to recommend a solution, or if it's just an expected behavior with the mini arrow. Looking at the recent Flite Test Arrow Through the Woods video, it looks like Josh is dealing with the same flight tendency on almost every launch too.
Bayboos
Active member
Apply throttle first, then throw it in the air. One problem (prop inertia) less to worry about. You will be surprised how big difference it makes to do it in the right order.
Apply throttle first, then throw it in the air. One problem (prop inertia) less to worry about. You will be surprised how big difference it makes to do it in the right order.
Doh! That certainly meets the K.I.S.S. standards! I'll have to remember that when I build one of these. Thanks!
Thanks for the advice! The weather isn't great atm so I can't really go out and test. I have always grabbed the plane by the motor mount and thrown it over head, then apply throttle quickly. I always found I would break props if I gave it throttle before launch because when it crashes, I'm not fast enough to switch it off lol!
Grauwulf
Member
I have to agree with the conclusion you're dealing with torque roll. I found the technique that works for me is to do a backhanded toss with my left hand (I fly Mode 2) and run the throttle up with my right hand before putting my hand back on the right stick before I toss it. I'm launching at about 3/4 throttle or so.
I have just tried the 3000kv version. Using a 5x5APC prop, it was able to fly. But due to the wing only weighing 190g (I upped the ESC to an overlander 30A which increased the weight quite a bit), the occasional gust of 20mph wind would cause the plane to literally just... blow away like a piece of paper. But when the gusts calmed, it did fly well. Not particularly fast I might add. Maybe I need a smaller prop to get the RPM? Could it be my battery? I am using a 450mah overlander which is 45c.
