Tommygun

My Feedback: (2)

I know that every year, we have more advances in electric power and performance. Are we at the point yet where a hot, 2 stroke .60 piped motor can be replaced by electric power, and still maintain similar performance/top speed? I'd want to maintain 10 minute flight times as well. I have a couple of older pattern aircraft that I was considering doing a conversion on, since parts for the original engines are no longer available. Apologies in advance if previously discussed.

petec

My Feedback: (58)

Getting the same power can be done but flight time is going to be a function of battery voltage/capacity which will mean weight and given the size of a 60 sized pattern bird you may also run into size constraints.

Tommygun

My Feedback: (2)

That's what I was wondering, sounds like we're not quite there yet. Electric is pretty great, but still has an upper limit. 10 more years maybe...

blvdbuzzard

I would say that my Monster Power 60 with a 18X8 prop, 5500 6s battery has about as much power as my old Webra Speed .61 black head with a pipe. I get 10 plus minute of flight time. I am looking at pulling the Webra and putting in a electric motor.

I would say it is more like having a four stroke engine then a screaming two stroke. It has the pull but might not have the flat out speed.

I have the 60 electric in a low wing trainer I am using for a glider tug. I have done four launches and then flew until the gliders landed on a single charge. I was doing mostly touch and goes with a little bit of rolls and loops. Nothing real hard but I flew for over 30 minutes. This was at 1/2 to 3/4 throttle. I was testing how long I could fly before I hit the voltage cut off on the ESC. I have it propped to pull 42 amps right now static on a fresh battery. I can go up to 60 amps plus.

Now if I increase the prop I would loose the flight time but get a whole lot more pull. It is a trade off on flight times and power.

If you needed to run a smaller prop, Turnigy makes a high KV motor.

Give it a try, I think it will surprise you in the performance of the electrics now.

Motor's
http://www.hobbyking.com/hobbyking/s..._60_Glow_.html

http://www.hobbypartz.com/96m606-big...030-400kv.html

Battery
http://www.hobbypartz.com/98p-25c-5500-6s1p.html

ESC
http://www.hobbypartz.com/07e06-proton-60a.html

Buzz.

bem

My Feedback: (1)

Hi,

One of the more dificult things to solve atconverting an older 60 seize 3-gear pattern plane to electric is prop clearance.

If You use for example http://www.ecalc.ch/motorcalc_e.htmand try various candidates formotors, batttery (cells, mAh etc) and try various props You will find you are rather limited
to stay within motor limits and notget prop stall.
But it is always possible to experiment with varoius props that Youcut off tips on.

The power of the electric motors and batteries is here today so that is not the problem.

A taildragger style old pattern plane is no problem since You can have larger props on them that most of suitableelectric motors prefer.

I'm myself into investige my options for an 60 seize MK Blue Angel (1973 World Champion version - it was also earlier and later versions).
Wingspan 64 inch / 1630 mm
Wing area 697 sq inch / 45 dm2
Weight 7 1/4 lbs / 3350 gram

Distance from propshaft center to ground is 6,90 inch / 175 mm (if I follow drawing suggestion that I would like to follow)
Prop clearance with a 12 inch diameter prop would then be 0,90 inch / 22,5 mm.
Prop clearance with a 13 inch diameter prop would then be 0.40 inch /10,2 mm (not much).

I would like to use 6 cell LiPo, around 5000 mAh, about 30-45C with resonable weight.
I would like to use 100 Amp ESC (to be on safe side) with BEC (to save some weight - and I know I will get no redundancy if battery/ESC fail).

Cooling of motor, ESC and battery would probably be somewhere between medium to poor.

So far I got reasonable figures in eCalc with these selections as a starting point:

5000 mAh battery 30/45C
Charge state normal

Controller Max 100 A

Motor Hyperion Zs4025-10 (505 kv) (max 2200 watt, weight 416 gram)
(another alternative motor maybe could be Hyperion HS 4035-0500 or -0560)

Propeller APC Electric E 13 x 8 2 blade

When I press calculate in eCalc I get no red results so in theory I'm green to go:

Prop RPMwill be 10262, out will be 945.66 watt, efficency 83.6 % in entire drive package (out of optimal 89.6 %).
Let say the plane will get slightly heavier then a more ideal 7 1/4 lbs, lets say it will weight 7.7 lbs / 3500 gram, I will get
a watt per pound 945 watt/ 7.7 lbs =122 w/lb
Prop static thrust is 165 oz / 4677 gram and prop stall thrust 101 oz / 2861 gram.
Perhaps OK for a pattern plane?
About 6 min flight time (on full throttle) that probably will mean about 8 min with normal throttle handling.

I think that would give rather good performance to a 60 seize Blue Angel, but I will never know for sure until I try and experiment.

I have thekit, battery (DesirePower V8 6 cell 5200 mAh 35C, weight 760 gram / 25.7 oz) and I'm trying to decide on best electric motor for this plane that will cope with prop diameter requirement for this plane.
Not easy at all to figure out (for me).

/Bo

80sPattern

Tommy,

I think the answer is "yes" and we will see in the next few weeks. I am converting a Conquest IV (Designed for a YS 60 on a pipe) to electric. I started a build thread on it last May on RC Groups.

www.rcgroups.com/forums/showthread.php

Come on over and take a look. Would love to have you add your thoughts to the process.

Doug

jpecha

OK, I am the proud owner of a Balsa USA Northstar currently running a 5050 600kv motor on a 6S battery (11X8 prop). It is fast, but I want more. it weighs around 4 pounds. Can anyone give me a setup that will get me in the 150 mph range that will not break the bank?