23 pound twin
 

What would a 23 pound twin engine take in motors, batteries, esc and get me about 7-10 minutes of flight.

3 blade scale props 104" wing span, lots of scale goodies, not sure of how to operate at this point.
Jack

RE: 23 pound twin
 

what would it take? Probably about one to two thousand dollars?

RE: 23 pound twin
 

My one cent worth.

It would take two Axi 4130 motors, two 77 amp Jeti Controllers, and lots of research and development. If you are contemplating this, and you are the first to do it on that particular model, then the conversion will make you feel like you are re-inventing the wheel. I think Airflow might be low balling you, the cost might creep upward of $ 2,000.

If you have been flying this bird with nitro or gas motors already, I would not change at this point. With a bird this size the conversion should happen during initial construction.

Al

RE: 23 pound twin
 

A pair of Chrylser Hemis would work nicely but a couple of AXI 5100 series motors with two matching ESC and the largest amperage batteries you can afford.....this will be a big bucks project make sure you choose the correct components. Norm

RE: 23 pound twin
 

I agree it is big bucks, but cheap compared to scale turbine heli's which I have done too. Doing this right is the idea. Heck if a 8 foot long helicopter can be made electric, I think this PBY can.

Can 2 motors run off one ESC?

RE: 23 pound twin
 

Hi, Great choice of twins a PBY, one of my favorite all time aircraft. No you need a separate ESC for each motor but you can run both motors and ESCs off of one humungous battery. You can also feed both ESC receiver leads into a Y cord but you can only have one (red positive ) power wire attached otherwise you will be feeding too much voltage into receiver. You need both receiver leads into one attached to engine signal pins but cut one of the red leads. Norm

on smaller brushed motors you can use one larger ESC/BEC for both motors but only BRUSHED.

RE: 23 pound twin
 

Okay, now would you build with different materials, particularly in the wing? I am not a fan of foam wings, I can get cores tho. I was thinking buildup using CF for the spars and conventional stuff for the ribs, glass for the fuse.

Hey I appreciate the info, I am a convert to electric and have much to learn.

How humongus of a battery? 10s ?
Jack

RE: 23 pound twin
 

Foam core wings covered with wood and then glassed could be very heavy. I would use conventional wood construction with lightning hnoles in ribs tips etc. If possible you may consider Monocote for coveringv wing and surfaces rather than sheet and liqid finishes, you will save a bundle of weight this way. I use 22.2 volts on my 4120 and it seems just rigvht, but with your set up you are driving two motors, two ESCs so you will need double the amps. The volts to the two motors will remain the same 22.2 volts or whatever you put in but the amperage drawn will double so you have to have suffcient power in the batteries. Looks like at least 7 or 8,0-00 mas to me. I ssuggerst you check with the guys at Hob by Lo bby for exactly the right combo on your power. They are super guys and know their electrics. Norm

also make sure you use separate battery for receiver and servos don't use an BEC on this set up and I would use 6 volts with at least 2000 ma cells for receiver pack.

RE: 23 pound twin
 

gotcha

RE: 23 pound twin
 

Been doing some research. Leads me to more questions.

AXI has the 5330 XX and calculations from various web stores show that one motor will operate a model that weighs 18-22 pounds depending on flight style. But, since I will have to use 3 bladed props partly because of clearance, it looks like the best I can get is a 10/7 and maybe a 10/8.5. I cannot find any information on that motor with a 3 blade prop.

Additionally the 5320 XX should handle up to 15 pounds. Again no information on 3 blade props.

This is a big model 104" wingspan. Do I approach this from the perspective of what one motor will fly?

Anyone got good sources for 3 blade electric props?

Anyone got data on 3 blade on the above motors?

Which would you use? All will fit with room to spare in the cowls.

Regardless I will probably go with a Castle HV speed controller.

thanks
J

RE: 23 pound twin
 

Helijack, regular gas props work too. In fact as you will be needing large props those are the ones you need to use. If you can give me the kit dimensions and the glow/gas engines requirements I can give you a better idea of what to get and where to look...
Homero

RE: 23 pound twin
 

Helijack - You seem to be suggesting that a prop size of 10" would be suitable for the 104" PBY - I'd venture to suggest that this is way too small for a model of that size, even if you use 3-blade props. I think you need to be considering props in the range of 14" to 15" for a model that size in order to obtain enough thrust.