rkremser

Hello, I am planning on making a Coroplast flying wing with a pusher prop. I was thinking of using electric but if needed i'd go nitro. How does one decide which engine to use with what gearing and then the pitch of the prop. I understand its not really a exact science but i need some where to start. If my numbers are right it is going to be about 43 oz. Thanks in advance.

Cactus.

My Feedback: (1)

The engine isnt geared and as for prop size, your limited to whats available, just the standard sizes, 9x6, 10x6 ect which limits you to about 40 size max.
There is a nice coro pusher wing out there tho... www.mugi.co.uk

Steve Lewin

Electric motors are often geared and aren't restricted to using pusher props, you just run 'em in reverse. But it needs a bit more than just a weight to recommend a setup. Wing area ? How do you want it to fly ? Does your weight include motor/batteries etc, if so what have you assumed that they will weigh ?

Steve

rkremser

Hello, ya prob would have made sence to include that stuff, well the weight is approximated with a 400 type motor and all electronics. The plane design was generally going to be that Mugi wing, and i'm using a spreadsheet on their website to make the body material weight approximations. With what i was hoping to use would have in the end what is calculated as 5.3 oz per square foot as a wing load. Is this high or low for a powered wing like this, I was only working on some recomendations on the Mugi site but would rather the actual plane a slightly bit smaller but still stay fast and maneuverable. Thanks again for any input

Steve Lewin

I don't know the website you refer to but either it's a bit suspect or you need to double check your figures.

Weight 43oz and wing loading 5.3oz/ sq ft means it has over 8 sq ft of wing area. That's way way too big for a Speed 400. With that motor you should be looking at around 16-20oz flying weight. Anyway 5.3 oz/sq ft is far too low, there's no way you're going to get coroplast plane down to those sorts of figures. the material itself is too heavy.

Steve

Cactus.

My Feedback: (1)

Dont underestimate the Mugi Steve, they use mini gear and i think hes refering to the gilders wing loading and electric versions weight which wont mix.
It uses 2mm thin correx and is light.
www.mugi.co.uk

Steve Lewin

Good point Phil, I've seen plenty of Morgan's Mugis flying and they do a nice job.

rkremser, if you just build it to the instructions using a 6V Speed 400 and a Gunther prop it will fly. If you're building a bigger one and/or not using the correct 2mm correx give us a few more details.

As Phil says I suspect you're quoting a glider wing loading and an electric weight. They're not compatible, the electric flies at a much higher wing loading (and the gliders are usually ballasted to increase the weight, particularly for slope).

Steve

Cactus.

My Feedback: (1)

A guy down here has a 2mm clear one, i have the correx to build one, but not the gear at the mo, he has 5 blue LED's in the wing, but not raised so it doesnt glow as per the site.
those toy grunter props actully work well, better than the boat props tried one time