Sleeve nuts or longer adaptors?

[Bob Cotsford]

I'm converting from glow to electric so I have reasonable stocks of ic props but not thin electric ones. I'm using SK3 5055 motors with the bolt-on M8*1mm pitch adaptors but the thread on them is very short compared to a glow motor and won't accept the hub depth of an ic prop. I could do with either an adaptor with a longer thread or better still, a source of M8*1 sleeve nuts. Does anyone have a suggestion for aquiring either of these? I guess I could buy a lathe and make my own but that seems a bit extreme.

Edited By Bob Cotsford on 02/06/2018 12:48:43

[Adrian Smith 1]

Would it be easier to buy a small number of electric props rather than spend big money on a lathe and such like, Bob? They are lighter than IC and therefore puts the motor under less strain (better performance?). Depending on the size you want, they don' t cost the earth. Just a thought.

[Adrian Smith 1]

As a suggestion for that motor. Hope it helps.

**LINK**

[Bob Cotsford]

Thanks Adrian, that confirms the size as I've got a couple of 15*10s on order from MS Leeds for the Provost conversion but that still leaves me with a huge box of assorted IC props that I could use especially for testing. Even with the thin hub electric props the SK3 adaptor is a tight fit if you want to use a spinner, which I will do when I come to convert the La3 and Ki61 using this or similar motors.

[Former Member]

[This posting has been removed]

[Nigel R]

Just engines will do these long reach nuts for about a tenner a go. They will do custom thread if needed and put a metric thread on the front end to retain a spinner. Worth noting the Prop might need reaming on the front face to get the nut in.
Adrian Can you explain, How does a lighter weight prop put less strain on the motor and increase performance?

Edited By Nigel R on 02/06/2018 16:14:32

Edited By Nigel R on 02/06/2018 16:16:14

[Bob Cotsford]

Good idea Brian. The M8*1 is a fine pitch, M8*1.25 are easy enough to find of course. Ebay is full of them. I'll try searching with Reach Nut instead of Sleeve Nut and see if anything comes up.

Nigel, the thin blade props are aerodynamicly more efficient, or so the tales go.  They certainly take less current and give more thrust, though differences can be small.

Edited By Bob Cotsford on 02/06/2018 16:23:21

[Former Member]

[This posting has been removed]

[Adrian Smith 1]

Nigel, so the experts tell me it means less inertia, faster motor speed change which adds to the feeling of more responsive motor. Unless you know better of course!

[Glenn Philbrick]

Hi Bob,

I had a similar problem when I converted an Acro Wot to electric and did not trust the thin APC props to handle the power. I found that a great planes prop adaptor is longer so enabling me to use props with a thicker hub. The part number is GPMQ4968 and they are available from RC world the thread is 24mm long if that is enough.

[Bob Cotsford]

Hi Glenn, as it happens I already have a couple of E-flite adaptors that have longer threads. Unfortunately like the GP ones they are collet fitting, and the SK3 5055 motors that I'm using have the shaft emerging at the wrong end for my installations. I did try tapping one unit apart after loosening all the relevant grub screws but the shaft was flipping tight. Alternate spellings are available. If I could find a longer bolt-on adaptor I'd be a happy bunny but all the motors I've seen have uniquely sized bolt patterns and counterbores. A sleeve nut would be the answer, but as the thin electric props from MSL have arrived this issue can go on the backburner until I get the next conversion done.

Incidentally Glenn, I've run 1300W through 14 and 15" thin blade props without issue.  During the tests of the WotsWot conversion that's exactly what I subjected a 14*7 APC-e to.  My gripe with them is that it means spending £8-9 a time for props to try when I have a big box of assorted glow and petrol props left over from my ic days.  I can only hope lots of club members suddenly start breaking props so that I can offload a few

Edited By Bob Cotsford on 04/06/2018 18:45:58

[Nigel R]

Adrian i get what you mean now. Yes faster throttle response from lighter props.

[Adrian Smith 1]

Hi Glenn, I am a bit puzzled about your statement about not trusting APC electric props to handle the power. Do you have any evidence of that, assuming they are being used with the appropriate electric motor for the size you want fit? After all APC has a good reputation and I have been using them on a hot ship such as the Sebart Mythos 50E, using  the recommended Hacker  motor with no problem.

Edited By Adrian Smith 1 on 04/06/2018 19:34:39

[Nigel R]

Adrian don't the electric props have a lower safe rpm limit?

I seem to remember reading somewhere that speed models often use the ic props because of this.

I'd have thought sport models and anything going moderate speeds would be fine though?

[Adrian Smith 1]

If I can be pointed in the right direction of this article/research, I will gladly take it on board, Nigel. I have an open mind on it. I know and accept that beyond a certain point APC electric type props are unsuitable. A case in point is for 30cc and above equvalent electrics, the larger wooden electric props are deemed better. I have 30cc & 60cc equivalent electric motors (both Dualsky) which I have used JXF wooden electric props which are undoubtedly thinner than the IC equivalent. The latter motor using a 24 x 8 size. They perform very well and have not come to grief after 4-5 hours usage.

[Glenn Philbrick]

I have no evidence about the ability of thin props to handle the power, my thoughts where purely from an esthetic point of view in that they looked a bit out of place.It was my first model electric powered of a reasonable size and when compared to my IC acro wot it looked flimsy. This is obviously not the case as these props are used for models much bigger than mine.

[Nigel R]

Sorry Adrian, can't remember for sure where that came from. I think it was an RCG thread and the only facts discussed were the max tip velocities which APC quote on their site.