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May 08, 2011, 11:01 PM
Raised on 80's Pattern
Fatherof4's Avatar
Thread OP

Conquest IV - E-Power Build Thread


As some have you may seen in a previous post I have a Conquest IV for I started 20 years ago and never finished.

I am contemplating finishing it to add to my Classic Pattern collection of one.

However, I am thinking that building it as an electric might make more sense for me. Nitro is a blast from the past, but e-power is SO much easier. It would also allow me to fly at some places that wouldn't welcome a screaming YS 60 on a pipe.

So what do you guys think? I would value your thoughts.

If I make it e-power, I don't even know where to start with a power system. Thoughts on that??? motor, esc, 4S, 5S??

Can I keep this thing under 8 lbs? I want it light on the wing and this may allow me to fly at one local electric-only flying site.

Lastly, I'll warn you advance that this thread will be on-going for a long time. My limited building time will probably result in a very long build time.

Thanks in advance for your thoughts. I would this to be an interactive thread with all your good and bad ideas!!


EDIT 6/11/13:

Here is the video of the finished product to give you all inspiration:

Conquest IVe Video (6 min 39 sec)
Last edited by Fatherof4; Jun 11, 2013 at 08:03 PM. Reason: Added Video
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May 09, 2011, 10:29 PM
doxilia's Avatar

I would be lying if I didn't confess that the same thought had also crossed my mind - I have one too but in the raw - cores and fuse only.

I have never electrified a 60 size classic but because of that it would be an interesting experiment. Power required is about 1400-1600W depending on what you plan to do with it. I believe the props being turned are in the 13-14" diameter range which makes a conventional gear setup almost mandatory. This is one of the things that has actually kept me on the bridge regarding e-power since I find the C4 looks much better with trike gear. It could still be done with e-power and a 13" prop and some longish struts.

The other caveat is that the battery swap would happen via the belly pan which, with a nose gear, would make access to the "fuel" area a tad more tricky but again, still doable.

I believe that people are flying lighter 60 size classics (e.g., Dirty Birdy's & Curare's) with e-power and 6s. 5s could probably do it too but I don't like odd cell counts (they can't be serialized/parallelized easily) and in any case volts are good. I'd keep the pack light by going 6s and lowering the capacity. There are many good e-power references in the SPA community for the classics.

May 10, 2011, 12:11 AM
Raised on 80's Pattern
Fatherof4's Avatar
Thread OP

Thanks for the response. I hope I can count on you throughout this project.

My Conquest is set up for trike. I personally just cant get excited about a tail-dragging pattern ship.

I had been thinking about the battery swap myself. The nose gear will make getting a battery into the fuse impossible. I am afraid that putting the battery in the belly pan would create an imbalance in the ship.

I was thinking about a hatch from the top. Maybe the edges of the "canopy" can be the edges of the hatch. Hmmm....

I'm wondering if the inexpensive HK electric retracts that Beachflyer used would be good for the C4. I think I could modify to allow nose steering.

A little fiberglass work or a visit to FrequentFlyer would allow be to eliminate the opening for the YS motor head in the bellypan. But then I wonder if I should redo the "chin" because it is not necessary.

You asked what I would plan on doing with it.....flying pattern. I would be happy with "YS 60" performance in terms of power. Not looking to hover this thing. (Although, that would be funny!)

I am thinking of going HK cheap on the motor system like BeachFlyer did. What do you think?

Can you give me a link to "the SPA Community?"

May 10, 2011, 12:46 AM
Originally Posted by Fatherof4
I am thinking of going HK cheap on the motor system like BeachFlyer did. What do you think?

Can you give me a link to "the SPA Community?"

Hi Doug,

I"m in the process of doing my first 60-size epower conversion. One of our local flyers in Long Beach is Joe Ballasch, owner of Leisure Electronics and he's one of our go-to experts. He recommended this Neo and I think it will be a winner. It's about $75, more than the cheapo HK motors, but it may well be worth it, especially as it will run well on 3S 2200 mah Lipos and I have a ton of them, meaning I can combine them for 4400 mah to extend the run time.

Here's the Neo info, the SPA electric rules are also included.


CERMARK, 9830 Bell Ranch Dr, #101, Santa Fe Springs, CA 90670 /


Airplane Type Pounds Ounces Grams
Trainer or Slow flyer: < 16.8 < 269 < 7,600 based on 11.1V (3s LiPo)
Aerobatic: < 12.6 < 202 < 5,700 based on 11.1V (3s LiPo)
3D or Unlimited: < 8.4 < 135 < 3,800 based on 11.1V (3s LiPo)

Voltage range: 10V – 24V, suggesting 3S-5S LiPo, NiCad and NiMH are also acceptable

Props: TBA Electric type props
Brushless ESC: 80A and up

• Diameter: 50mm (1.97 in) • Length: 65mm (2.56 in) • Weight: 421g (14.8 oz)
• Shaft Diameter: 6mm (0.24 in) • Kv (rpm per Volt): 410 • Max Watts: 1,263
• Io: 2.0 (no load current) • Max Amp: 60A (100≡ C or 220 F) • Resistance: 20 mΩ

• Direct drive • Built for today’s power demand • Superior climbs
• Quiet operation • Dual ball bearings • Female ESC connectors
• Reversible shaft • High temp Neodymium magnets • Rear prop mount system
• Spare motor shaft • Complete installation tools & hardware • multiple installation methods


• 75 Watts per pound or 16 oz. ⇒ Trainer and slow flying scale models
• 100 Watts per pound or 16 oz. ⇒ Sport aerobatic and fast flying scale models
• 150 watts per pound or 16 oz. ⇒ 3D or unlimited maneuvers
• Watts = Volts x Amps • 1 pound = 16 ounces = 454 grams • 1 Horsepower ≡ 746 Watts

1. Determine your model’s gross flying weight. (Example: 27oz)

2. Identify your flying style for your model, (Example: 3D style flying)

3. Calculate your model’s power or Watts requirement using the above base chart. (Example: 27oz 3D type of model
requirement = (27 / 16) x 150) = 253.125 Watts or approximately 253 Watts)

3. Identify which NEO motor you will need. (Example: Need 253 W => NEO-480, because it is under the 280W)

4. Determine which kv motor within your power range is better for your usage. (Example: In this case you may prefer 900kv or 1,000kv to 1120kv because you have a 3D type of model. In general, lower kv, rpm per volt, motor generally will have greater torque than a higher kv motor of equal size.)

5. Select ESC: (Example: Calculate the approximate current draw using Watts = Volts x Amps formula, 22.8A = 253W / 11.1V. Now we have estimated that your motor will draw an average of 22.8Amp in a static situation. In this particular case we would choose the next higher Amp ESC such as a continuous 25A ESC or greater for a better margin of error.)

6. Select battery: (Example: your LiPo selection would be a little more difficult, because you will need to consider balancing. However, keeping most information intact, you will require the LiPo battery to be able to discharge at an average of 22.8Amp or better. Therefore a 2100mah LiPo with 25C (continuous discharge) will be fine because 25C rating on a 2100mah = 25 x (2100/1000) = 52.5Amp continuous draw. A 1320mah with 20C = 20 x (1320/1000) = 26.4A, which is also fine, because it is above 22.8Amp requirement. However a 15C rated 1320 pack will not be sufficient, because your motor’s max current demand exceeds the battery pack’s 19.8A continuous discharge ability.)

7. Estimate minimum static run time: (Example: You selection at this point will depend on weight balancing and run time. 2100mah provides a minimum run time at full power of 5.5 minutes = (2100 / (22.8 x 1000)) * 60.

================================================== ===================
SPA Electric Power

The Case for Electric Power in
Senior Pattern Association
Authored By Warren Oliver
Presented by Mike Robinson
Advantages to SPA of Allowing
Electric Power

• A more inclusive approach.
– Many of our club members have never flown
anything but electrics and are very unlikely to ever
try SPA for that reason alone.
– Reduces the cost of competing

• Noise reduction. This continues to be a
problem for model aircraft in general. We
cannot risk our flying sites.
The Advantages to the Individual

• Lower initial cost to participate

• Lower cost of operation

• Aircraft last longer

• No engine flameout or failures to return from

• Less flight gear required

• It’s fun to try new things
What Should We Compare To?
FS-91 Surpass II w/ Pump

• Displacement:0.912 cu in (14.95 cc)

• Bore:1.091 in (27.7 mm)

• Stroke:0.976 in (24.8 mm)

• RPM:2,000-12,000

• Output:1.6 hp @ 11,000 rpm

• Weight:23.9 (678g)

• Recommended Props:13.5x8, 14x7, 15x6, 16x6

• Price-$379.99
Buy in Cost For Power System

• Internal Combustion:
– OS 91 FS with Pump $379.99
– Fuel system $15
– Servo $30
Total $424.99

• Electrics:
– Motor $40
– ESC $40
– Battery $75
Total $155.00

Incremental Cost Per Flight

• Internal combustion engine:
– Cost of fuel $20*10 oz/64 oz=$3.12

• Electric Batteries:
– Cost of the electricity is almost nothing
– Cost of the battery $75/200=$0.37

How Do We Determine an Equivalent
Power System ? – Two Ways

• Power: Brake output HP for internal combustion
engines are equivalent to input Watts multiplied
by efficiency for electric motors.

• Total energy available per flight: Size of fuel tank
for internal combustion engine and is equivalent
to mAh multiplied by voltage for Batteries.

Equivalent Electrical Power

• Output power calculation:
1.6 HP =1.6*745.7 Watts/HP=1193 watts

• For electrics we measure input power

• Electric motors are at best 85% efficient:
1193/0.85=1403 Watts of Input power (see
graph in next slide)

• I understand Jamie Strong first made this
calculation and my experience is that it is
precisely correct.

Data From Electric Motor, 6S 5000 mAh Battery
1400 Watts Yields 10200 RPM on a 13.5x9 APC

Calculation of Battery Capacity

• 1400 Watts/22.2 Volts*(7.5/60) hr*66 %
Throttle=5.203 Ah or 5203 mAh.

• If one uses 66% of the 1400 Watts of power available
on average through the flight, a 5200 mAh battery will
get you through a 7.5 minute flight.

• My own experience is with an electric motor that is
virtually identical to an OS 91 FS (13.5x9 APC, 10,500
Max RPM) I can make it through the expert pattern and
have enough for a couple of extra passes in case the
runway is tied up with a 6S 5000 mAh battery.
Proposed Rules

• No propeller larger than 13.5 inches in diameter will be
allowed on any SPA aircraft.

• The highest nominal battery voltage will be 22.2V. For
Lithium Polymer batteries this means a maximum of 6
cells in series (6S).

• The highest capacity battery will be 5200 MAh.

• The original manufacturers label indicating voltage and
capacity must be attached to the battery and available
for inspection.

• A mechanism for disconnecting the power from the
electronic speed controller will be provided on the
exterior of the aircraft. That mechanism will be clearly
available, easily operated, and have visually clear states.
A simple example of the intension of this rule is a plug
that is visible and can be manipulated from the outside
of the aircraft.
Proposed Rules (continued)

• No electrically powered braking or reverse torque
of the propeller will be allowed.

• The maximum power available to the motor will
be 1400 watts at any time during the flight.

• The intension of the rules concerning battery
voltage , capacity and wattage are to produce a
verifiable system that has capabilities similar to
an OS 91 FS internal combustion system. No
systems intended to circumvent this intension will
be allowed.

• Electric pilots have an advantage do to throttle response- Quite
the opposite is true. Half throttle for glow engines supplies the
same power throughout the flight. It can vary by as much as 30%
during a flight for electrics. The torque curves are different but
when did you last hammer the throttle and feel the your IC engine
just didn’t respond fast enough?

• Electrics have more drag during vertical decent. Electric motors
provide very little resistance to prop free wheeling. We used to put
four bladed props on our IC AMA pattern planes to increase drag.
Clearly, the prop wants to free wheel faster than most internal
combustion engines idle.

• The power of electrics is hard to police or limit- I believe I have a
set of rules that is easily enforced.

• People using electrics will win more contests. Folks it’s 99% pilot
and 1% equipment. Just look at how many times I beat Jerry, Jamie
or Ellis this last year!

I respectfully request that the
proposed rules be voted on as is
without amendment or revision unless
absolutely necessary. I have thought
quite carefully about what rules will
serve us well and believe that these
rules are about right. Thanks for your
time and consideration.
Last edited by Luckyducky; May 10, 2011 at 12:58 AM. Reason: Added info
May 10, 2011, 09:13 AM
Registered User
Three Cells ?
May 10, 2011, 10:42 AM
RC since 1979!! AMA 112747
beachflyer's Avatar
I have done the converstion of a 120 size pattern plane.
I have around 160 watts per pound and it flys great. I fly for over 7 minutes hard with 6cell 4500 nano's. I take out about 3000 to 3500 during the 7 minutes. I am using inexpensive equipment from HobbyKing. I think your plane will come out lighter. I did no building on this plane so it came out gasser heavy, 10 lbs. I think you will be lighter finishing the plane yourself from the start. No messy cleanup. I really like the sound too.
Good luck. I will say before installing motor from Hobbyking make sure to sure up all set screws with locktite and put a layer of epoxy over magnets. I had to do this after installing. It will save you some headache. I also put whole in front of spinner an drilled some holes in back plate to cool motor. Comes down slightly warm now.
AMA 112747
Last edited by beachflyer; May 10, 2011 at 10:48 AM.
May 10, 2011, 11:26 AM
Raised on 80's Pattern
Fatherof4's Avatar
Thread OP

Are you happy with the HK retracts? Do you think I can convert one to a nose with steering?


May 10, 2011, 11:36 AM
doxilia's Avatar
Ed, John,

great info.

I also have a few 3s 2100-2650 packs and thought about using them. Problem is, one wants 4500-5500 capacity which means they have to be both serialized and parallelized which makes for a 4 pack swap each flight - not great. Of course the packs can be charged beforehand but charging 4 packs efficiently requires at least two chargers or a multipack charger. I have been thinking about getting a 4 port charger especially since HK seems to have some that are quite affordable but even so, I think swapping two packs might be a better approach.

Question is whether to use high capacity 3s packs for a 6s1p serial setup or half capacity 6s packs for a 6s2p setup. The latter strikes me as more convenient simply because I can't see myself using ~5000 3s packs for any other application. ~2500 6s packs might be more versatile but I guess its 6 of one, half a dozen of the other. Of course one could just get two 6s packs of the right capacity and call it a day.

I have heard of several users having to glue in the magnets in their Turnigy motors. It seems that adhesive is not used sufficiently in Asian manufacturing as it is also a common problem with ARF's - or so I'm told. Good news is that once it's done, they are pretty good. Some bearing issues but mostly shaft issues. The latter are readily available and probably not a bad idea to pick up one or two with the motor.

These two (although backordered) might do the trick on 7-8.5 lb 60 size models.

May 10, 2011, 11:45 AM
doxilia's Avatar

I will follow your thread with pleasure - I'm looking forward to it.

What mains do you have in the model at the moment? If you are happy with the mechanical setup in the wing, you could perhaps just pick up a nose unit from Robart if HK doesn't have what you need.

The nose setup in C4 makes for a pretty easy install I think. You could use a separate flat servo for its retraction and run some P-P wires from the rudder servo for steering. A bellcrank might be needed - not sure.

On the other hand, the electric retracts are very easy to setup - obviously. I haven't used the larger 45 or 60 kind yet (other than the older vintage Kraft Multicons) but I'm close to finishing two wings both of which use the smaller 25 sized versions. if you like the "simple is beautiful" idea, electrics are definitely the way to go.

May 10, 2011, 12:44 PM
RC since 1979!! AMA 112747
beachflyer's Avatar
I am happy with the retracts. They use 5mm gear. Had a heck of a time finding them. Hobby horizon sell them. I had smaller verision in my Habu before motor wires melted elevator servo extension and she went in at 100mph. You can make them work and they are inexpensive.

Originally Posted by Fatherof4

Are you happy with the HK retracts? Do you think I can convert one to a nose with steering?


May 15, 2011, 10:28 AM
doxilia's Avatar

how's progress on the C4 going? Are you sorting out gear and such?

Seems like it might be time to get those wing tips shaped!

May 15, 2011, 11:20 AM
Registered User
Here is a link to a Youtube video of an electric Aurora:
Aurora rc plane electric -Quebec C2VM - 33.6 Volts (8s lipo) (7 min 7 sec)

I thought you may be able to get a "feel" of it's performance....There is a thread somewhere on this website about this airplane, it's pretty old but I've come across it several times over the years...You may find some useful info??

P.S. I know nothing about electric stuff so all those specs are meaningless to me...I just thought it may be a useful base line??


Here is a link to the thread. I'm sure technology has come a long way since then but maybe there is some useful info??
Last edited by navav2002; May 15, 2011 at 11:27 AM.
May 15, 2011, 05:22 PM
doxilia's Avatar

there is also Jeff's excellent Aurora scratch build thread from plans. Plug-in wings and electric power. They both used the same motor.

May 16, 2011, 01:17 PM
Raised on 80's Pattern
Fatherof4's Avatar
Thread OP

The only progress I have made so far is in my head. Spent what little modeling time I had this weekend flying the Atlanta getting ready for our Classic Fly In this weekend.

Yes, I will shape the wing tips just for you!


That link was VERY helpful. Although, if I take as long as Jeff, I will be a grandpa before the C4 flies!

I am deffinently going to make this an E-Powered pattern plane. I think I'll stick with the mechanical retracts on it. I have them and the 180 servo, so why not. Also, without a pipe and mess in the belly pan, I can put the retract servo exposed to the belly and operate all three retracts with one servo.

After listening to the e-powered Aurora I want to try to use the soft mount that I was going to use with the YS. I'll take a picture tonight and post it. I like the idea of quiet. I will never forget hearing Chips Hyde's Dalotel (sp?) and liking the quiet. Will help me fly it at more places too.

What servos should I consider? I want to keep costs down. I have some old Futaba S131's like in my Atlanta, but maybe some new HiTecs would be good. Also, one elevator servo or two small in the tail? Any thoughts?


May 16, 2011, 05:01 PM
doxilia's Avatar
Originally Posted by Fatherof4

Yes, I will shape the wing tips just for you!


Excellent! looking forward to it!

Low cost servo's... how about some mini's in the wings (225's) and some 475's for elevator and rudder. An 82 for throttle.

Not the most amazing servos in the world but decent and affordable.

Just an idea.


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