Propellers for 1/6 scale 'birds

[Graham Davies 3]

Evening all,

 

Getting towards the denouement of my build. It's a scratch build 1/6 scale (74") Mk1 spitfire based on P9374, which was dug out of the calais sand and restored to flying. It's scale-ish and won't win any competitions, but looks pretty good. I'm new to this scale with my models up to now being smaller.At this size, I keep running into new issues to solve, and today's relates to propellers...

 

I have 16x8 master airscrew scimitar in my stock, and according to e-calc, this should be just about OK on my chosen motor (5065 320kv on 6S), but ideally I need a 17 or 18x8. I'm not ooking for scale diameter (unlikely) or 3 blades (I've already cut the spinner!), but what props would you as the great and good suggest? I can find precious few at this size that are not either wooden or APC, which look silly. Wooden is a risk on our strip and nose-overs are a real possibility.

 

What do you suggest, and where would I get them from?

 

Thanks all

 

Graham

[Philip Lewis 3]

A 50X65 is quite a hulk of a motor and 320kv is quite low for 6 cells as well so should quite easily turn a much bigger prop. I currently use 50X45 motors on six cells at 430 KV turning 16X10 and 17X8 props as well as 320KV 50X55 320KV motors turning 18X10 props but on eight cells so I think you have scope to go quite a bit bigger.

 

I used to have a 50X65 245 KV that turned a 20X13 prop on ten cells but that was very marginal.

 

I used to use Hobby King Aerostar wood props but haven't bough any for years but were always available and quite resonably priced back in the day even including the postage from China.

 

 

[steve too]

I would see if electricwingman or Model Shop Leeds have an Aeronaut CAM carbon power prop in a suitable size. Failing that, you could always paint a wooden one.

[Philip Lewis 3]

The trouble with carbon props is A) cost and B) very fragile, they break even easier than wooden especially the light electric ones. Personally (although all of mine are carbon as specialist planes) I would avoid carbon if I could, especially in a model likely to nose over.

[leccyflyer]

Wheelspin advertise an 18"x8" in the Master Airscrew "Classic" Series.

 

https://wheelspinmodels.co.uk/i/290739/?srsltid=AfmBOoolmoiHilt08Wh-alevXLZNSpKqfsr80OiIAazd2B8cC_5WT12PHXM

 

I'm not sure what the Classic series indicates -I have no personal experience of those so don't know whether they are similar to the okay-ish MA Electric props, which I've used a few, or their Paint Stirrer series.

[Brian Cooper]

Ali Express is currently banging out big props at bargain prices. 

[Jon H]

1 hour ago, leccyflyer said:

I'm not sure what the Classic series indicates

 

Its a sign they are excellent at turning RPM into noise, and are as efficient as a railway sleeper bolted to the engine. On a cub or tiger moth they might be ok, but better alternatives are out there for something like this. Also on electric they will suck down amps like its going out of style. They are also very heavy and this can cause issues with phasing from the ESC as they do not spin up as quickly as the motor maps expect. 

 

Graham my advice would be to buy a 17x8 apc, nail that on and go flying. Yea they are ugly, but you cant tell that when its spinning and like on the c/g thread before, the object is to get it through the maiden flight. Nothing else matters at this stage. With that out of the way and the c/g, rates etc dialled in you may find it is more nose over resistant than you expect and a wooden prop has legs after all.  

 

 

 

 

[Paul De Tourtoulon]

7 hours ago, Jon - Laser Engines said:

 

Its a sign they are excellent at turning RPM into noise,

So do Graupner's ( video) and APC, look on my utube channel at my Phantom F 4,,,

 

The Master airscrews aren't that bad, and cheap and chearfull in the sizes over 14".

 

[Graham Davies 3]

Thanks all.

 

Jon, I was hoping you'd pipe in! Thanks for that. I think it's a good point to take performance over appearance, particularly early doors. And I agree that APC are ALL performance. I'll get one on order..

 

Graham

[Jon H]

16 hours ago, Paul De Tourtoulon said:

The Master airscrews aren't that bad, and cheap and chearfull in the sizes over 14".

 

MA are the worst of all the props currently available. A friend used one of the same dxp of an apc on his YS and it crippled its performance. Better revs on the ground, but in the air it was just spinning the power into noise. The old graupner super props at least offered good performance. Their G sonic range run very fast, so you need to go up an inch or two in diameter or pitch to stop them howling like crazy due to the revs. 

 

The old bolly props were very good but i do not think you can get them any more. 

[leccyflyer]

The Mater Airscrew electric series props are not that bad and their electric wood series are lovely props. Agree that their IC standard props are horrible and the square tips are unnecessarily noisy. 

 

Webbies still have a few Bolly props available, as end of line items, but none in the sizes that Graham was looking for.

 

https://www.servoshop.co.uk/index.php?area=props&make=Bolly&title=Bolly+Propellers

[john stones 1 - Moderator]

Graupners were a better bet than a MA, both long since bettered by APC, bit daft to put a nice powerplant upfront then stick a rubbish prop on.

[leccyflyer]

One thing with APC- Es John is that sometimes they are a big problem to fit where you are using a spinner - the root of the prop blades are often extreme, with a substantial chunk of prop well behind the rear face of the prop boss. I've had to abandon fitting one on a couple of occasions, because there simply wasn't room to seat the propeller boss properly, where the spinner had a backplate. I don't know why they do that, nobody else seems to.

 

In the OP there's a concern about pecking the ground and that is somewhere that APC-E can be a bit of an issue as they love to shed a blade with the slightest touch on the ground if they are running.

[Dickw]

Not seen them mentioned so far, but there are other brands that might suit, such as

Biela   https://www.iadmodeldesigns.co.uk/bielaprops.php

or Fiala  https://esoaringgadgets.co.uk/motors-propellers/fiala-prop-company/fiala-propellers.html

 

Not as cheap as some perhaps.

 

Dick

 

[Paul De Tourtoulon]

5 hours ago, Jon - Laser Engines said:

MA are the worst of all the props currently available. A friend used one of the same dxp of an apc on his YS and it crippled its performance. Better revs on the ground, but in the air it was just spinning the power into noise.

say no more,,,,😂

 

[john stones 1 - Moderator]

Anyone got a couple of Paracetamol ? 😉

[Graham Davies 3]

Update:

 

The 1/6 scale depron spitfire flew at the weekend. I went with Jon's advice (thanks Jon, usually right on the money!) and fitted a 17x8 APC. I sprayed it black and painted the tips and the shape then became rather unnoticable. The model itself was off the ground at 2/3 throttle anyway, so it has more than enough. I didn't bother with a tacho reading (what was I going to do about it, whatever it told me!), but at 6s, a 320 kv motor is spinning at around 7.5-8k. For this 'bird weighing just 8punds 6 ounces ready to fly, that is more than enough...

 

Thanks again everyone, it's been emotional...

 

Graham