Prop adapters
09-01-2010, 03:23 PM
#2
RE: Prop adapters
Joe, I would be interested to find out what your issue was. I had an "incident" at a contest last weekend. I am running a 4035-330 on 8s and a 16-8 APC. Tell me if if this sounds like what happened to you.
After landing my last flight on Sunday I noticed that the prop was loose. On getting home and removing the spinner and prop, I found that the aluminum back plate had welded itself to the shaft. I guess that when the prop came loose the prop and spinner started to spin on the shaft. I did seem to notice a momentary loss of power on and up line, but the friction between the spinner backplate caused them to weld themselves together. After this happened the spinner was driving the prop.
Now I had balanced everything, but apparently the screws holding the motor to the X mount had come loose. Motor shaking on the mount is probably what worked the prop nut loose. Like I said, everything was balanced pretty well, so there was not a lot of vibration, but apparently it was enough.
My solution. . . Locktite on all motor mount screws and a jam nut on the prop shaft.
O.K. I just reread your post and you are talking about the True-Turn type adapter. There are two types of 8mm threads commonly used. one has a 1mm pitch, and the other is a 1.25mm pitch. I believe True Turn sells both. Measuring mine with calipers, I get a 1mm pitch
After landing my last flight on Sunday I noticed that the prop was loose. On getting home and removing the spinner and prop, I found that the aluminum back plate had welded itself to the shaft. I guess that when the prop came loose the prop and spinner started to spin on the shaft. I did seem to notice a momentary loss of power on and up line, but the friction between the spinner backplate caused them to weld themselves together. After this happened the spinner was driving the prop.
Now I had balanced everything, but apparently the screws holding the motor to the X mount had come loose. Motor shaking on the mount is probably what worked the prop nut loose. Like I said, everything was balanced pretty well, so there was not a lot of vibration, but apparently it was enough.
My solution. . . Locktite on all motor mount screws and a jam nut on the prop shaft.
O.K. I just reread your post and you are talking about the True-Turn type adapter. There are two types of 8mm threads commonly used. one has a 1mm pitch, and the other is a 1.25mm pitch. I believe True Turn sells both. Measuring mine with calipers, I get a 1mm pitch
09-01-2010, 08:43 PM
#3
RE: Prop adapters
Having more of a problem with the threads and the adapter gripping properly to the motor shaft. I had to machine my current adapter to accept the bolt for the Tru-turn spinner. Seems Tru-turn and others make the right adapter for up to 6mm motor shafts; I have an 8mm motor shaft.
I was wondering if you guys were using steel adapters (seems logical) and if any came pre-tapped to accept a tru-turn bolt.
I was wondering if you guys were using steel adapters (seems logical) and if any came pre-tapped to accept a tru-turn bolt.
01-31-2014, 08:11 PM
#7
Who is using the Neu aluminum prop adapter (aluminum shaft version)? Working OK?
I just got one from Neumotors. I am seriously disappointed and concerned with this design. I'm putting together something to help illustrate the issues I have with it, but I believe it is a flawed and unsafe design.
I just got one from Neumotors. I am seriously disappointed and concerned with this design. I'm putting together something to help illustrate the issues I have with it, but I believe it is a flawed and unsafe design.
02-01-2014, 12:34 AM
#8
Here is a picture. The prop adapter slides all the way down the P42 shaft until it 'bottoms out' on the C-clip at the gear box. When the collet fits over the prop shaft, it protrudes beyond the prop adapter - it too hits the c-clip. If you remove the prop adapter slightly from the gear box, the slots cut in the prop shaft extend beyond the tip of the P42 shaft. The collet on this prop adapter is very thin, so it does not support the prop shaft for the length of the slots like most others do.
So, the tip of the motor shaft is not 'buried' in solid metal, it is only surrounded by 4 tongues of 1mm aluminum. I don't see what would keep the aluminum from bending or stretching at the end of the motor shaft with any side load. This thing is supposed to be able to swing 21-22" propellers. I don't trust it. The slots should be at most half the length of what they are now, such that they are fully surrounded and supported by the clamped-on collet.
This is disappointing, mostly because it's coming from the maker of (in my opinion) the best motors there are.
The $6 Great Planes adapters aren't bad! They have a 3/8" shaft though (slightly less than 10mm but fairly robust), and require drilling and tapping for the spinner. They seem to be the best thing out there (barring the pricey Tru Turn adapter which I have not seen in person yet).
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMSG7
So, the tip of the motor shaft is not 'buried' in solid metal, it is only surrounded by 4 tongues of 1mm aluminum. I don't see what would keep the aluminum from bending or stretching at the end of the motor shaft with any side load. This thing is supposed to be able to swing 21-22" propellers. I don't trust it. The slots should be at most half the length of what they are now, such that they are fully surrounded and supported by the clamped-on collet.
This is disappointing, mostly because it's coming from the maker of (in my opinion) the best motors there are.
The $6 Great Planes adapters aren't bad! They have a 3/8" shaft though (slightly less than 10mm but fairly robust), and require drilling and tapping for the spinner. They seem to be the best thing out there (barring the pricey Tru Turn adapter which I have not seen in person yet).
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMSG7
