geared motor?

[Bob Black]

Hi to you all and a Very Merry Christmas

 

Hope this is the correct section on the forum

On several plans particularly vintage type mobels it advocates ie. "400 geared motor" or similar

I have searched dozzens of sites for geared motor, including this one, but come up blank is this something one has to machine oneself or am I missing something ( I dont have access to a lathe)

 

Thank and Regards

Bob

[Stephen Grigg]

I dont think so Bob,Ive purchased  selections of old stuff and found motors with gearboxes on them,quite simple set up of just 2 gears to reduce the prop speed.Probably with the advent of brushless and speed controllers not needed so much because you can control the speed much better now and there is such a vast selection of motors and controllers now.

[Bob Black]

Thanks for quictk reply Stephen

 

It could probable be done by choice of prop as well as the ESP, simple Eh! Thats me

Thanks again 

Regards

Bob

[Stephen Grigg]

hu bob I tend to chat to Galaxy or BRC they no all the stuff and are very helpfull mind you know one is as knowledgeable as out Timbo.If you put on here your plan and requirement he"ll come back with all you need to know.Weight of the model type of model etc all helps him

[Hamish]

I thought the purpose of the gearbox was to allow a small high reving motor to turn a larger prop which it could not do on its own??

[Stefan Hafner]

As far as i'm aware the you're right there Hamish, the reason being that the current draw is lower so we get to fly longer , of course its not so much of an issue these days with LiPos and better motors

[Tim Mackey]

A half decent brushless motor of the right Kv will be far better ( and likely cheaper these days )  than a geared brushed setup.

Happy to advise if you post details.

[GONZO]

True Hamish but that was mainly for brushed motors in the past. With the advent of brushless outrunner motors giving good torque from physically small motors brushed motors and a gearbox are, I would suggest, a redundant technology for general plane flying. As 'Timbo' would say 'brushes are for floors!' Thats not to say that in a limited specialist field geared inrunner brushless motors are not used.

Bob, put a request in to Timbo quoting the plane specifications and I am sure he will give you a range of modern alternatives to the specified '400' with gearbox power source. Or, you could consult the electric flight guides on this forum and have a go at working a system out for yourself and then getting the OK from the master.

[Frank Skilbeck]

Bob a typical brushed 400 motor had a Kv (rpm per volt) of over 2,000, and you'd use something like a 4.75 x 4.75 prop which would be no good for a vintage model if it wasn't geared down. With brushless outrunner you can get them in a whole range of KV's to suit the application.

 

If you know the weight of the model in question it would be pretty easy to suggest a motor, for a vintage model something with 80 watts per pound (model weight) would be maore thans required.

 

I replaced the 400 direct drive motors on my Twin Star with these way more power than the 400s they replaced

[Erfolg]

I have in principal to agree with the comments, which run along the lines, "put in an lowish Kv Outrunner".

 

As many others I have used various gearboxes in the past. The low cost types for 400/480 and 600 work, at the expense of overall efficiency. Although promising much, they deliver little. As the increased efficiency of a large diameter propeller is balanced against the inefficiency of the gearbox. It is always worth remembering that the useful power into a brushed 400 is only about 80w. Whereas the outrunner can easily take 120-300w for a similar overall package size.

 

The type of gearbox that are used with inrunner brushless, are precision engineered units and have very good efficiency levels. However the issue then becomes one of pinion bore diameter and fits and how the motor gearbox are assembled. This set up is excellent, but the financial cost is generally horrendous, compared with an Outrunner. The only real advantage is the small diameter of the set up.

[Bob Black]

Hi and thanks Guys

 

Sorry for slow reply but not been able to get to computer ( something to do with something I think called Christmas )

 

The plan I was concidering  for is  the "Pix-e major" as in Dec issue of  RCM&E

I have several smallish motor set-ups that should do nicely

 

Cheers

 

Bob