Hi

Need help with the electronics for my griffon 2000.
It is being built according to Mark Porters plans.
I was thinking in a 540 motor for thrust and a 600 for lift (3 blade 7x4propeller for the 540 and 3 blade 6x4 propeller for the 600).
Battery maybe 7,4V 2 cell lipo with 1800mAh 15C(one for each motor).
ESC i really dont understand anything, but i guess i need at least 40 Amp for the 600 and a forward reverse 30 Amp for the 540 motor...

What do you think?
What are your settings?

Thanks for your time

Hello there

the model works better wiht two speed 600 motors the prop sizes seems fine allthough the pitch on the thrust may be too much for the motor to handle so cheack the motor specs before you try it with regards to the speed controllers i would go for the highest amp you can afford 50-60 amp is ideal as then you know you are going to be ok.the other option is to go brushless setup but this can be quite expensive whats your buget like?

hi, thanks for your help.

My budget is limited so i am trying to spend as less as i can... I will try to be under 100$ for one or two motors, 2 esc and 2 lipos... Ebay will be my best friend...
I wanted 6x3 and 7x3 but i couldnt find... I also wanted 4-blade propellers but, again, i couldnt find anywhere....
Can you suggest me any esc in specific or where i can find 4-blade propellers?
What do you think about the lipos i mentioned?

Best regards
Jose - Portugal

if your buget is not great then lipos wont help as they are not cheap and require special chargers have you thought about nimh batteries they are cheaper tha lipos and still will do the job as the Griffon will take the weight if built light for the lift motor you dont need a 4 blade prop as you will get dirty air ie there will be a point when the prop is spinning that air will not be going anywhere for a short time.a two or three blade is better as for the thrust the same applies but if you realy want a 4 blade prop you wont get one at the reqired size on the common market so the other option is to put a vario prop in http://www.ramoser.de/home_e/variopr...rioprop_e.html as for ESC have a look at m tronicks they do some nice ones but they do require setting up http://www.ramoser.de/home_e/variopr...rioprop_e.html or try Ebay

I already have a lipo charger, and because i am building with ply a little heavier than the recommended, i must go for lipos to make up for the extra weight...
As for the propellers i will follow your advice and use 3-blade ones..
I will look into ebay for the esc...

Thanks

what size ply are you building with?

1mm and 2mm birch plywood

You may find that the model is too heavy to work using that size ply i am not sure i have not see anyone build one with timber that thick the upshot is that a bigger motor may be required which will increase the weight then a bigger battery is needed again increasing the weight or it may work but runtimes will be short why did you use such a thick plywood?

Because i couldnt find the specified measures....

Hi Jose,
How are you getting on? As Tim has said, plywood that thick will give you a very disappointingly heavy machine. Ideally you should use materials like balsa, thin marine ply (0.4 and 0.8mm) or liteply. However, if you are on a tight budget, you could try replacing some of it with depron (I have done this with mine with good success - the side decks and cabin are all 6mm depron with the decks glassed for robustness).
In terms of motors, you actually don't need a particularly powerful motor for lift - the key is getting a well designed and well fitted skirt, and making the lift duct to a very close tolerance. Originally I actually ran it with a 6x4 four blade Graupner pusher prop on a (don't laugh) speed 400 motor. I then upgraded to a speed 480BB which worked well. I then went bigger still to a 540 with a two blade prop and found my run times suffered because the lift would run our of juice before the thrust as it was drawing more power than is necessary, so I am going to go back to a 480. But getting the model to hover is relatively easy. You can do that even with the heaviest of models. Making it perform well is where weight becomes important, hence the use of lightweight materials. Mine weighed about 8kg when I first built it and it's performance was sluggish (based on a 600 motor on the thrust). However, I did some major rework which is when I replaced a lot of the structure with depron, and shaved a third off the weight. I also did some experimentation with motor and prop combinations. I now have a 8x3 prop (hard to find but worth seeking) with a cheap 540 motor and get much better performance. The reason I went for a smaller pitch was that when the prop runs it is essentially in stall, so higher pitches don't work as well as they should and cause the motor to run hot, whereas a lower pitch allows the motor to run at close to it's natural speed and thus you get better efficiency and since the prop can turn faster, this works to improve thrust.