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Author Topic: AIRPLANE SEARCH  (Read 719 times)

Offline FLOYD CARTER

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AIRPLANE SEARCH
« on: February 18, 2009, 04:48:27 PM »
I know I'm going about this backward!  Instead of selecting a model, then finding the right combo motor and battery,  I have the following components:

Hacker A30-10XL

2 ea BP3200 LiPo, in series, giving 4S at 3200 mAh

Weight of all this is 18.9 oz

Now, how big should the stunter be (for full-bore stunting).  Need:

Wing area (assume 18% airfoil) ?
Flying weight ?
What prop?

If necessary I can design my own, or scale up-down some existing design.

Floyd in OR
90 years, but still going (mostly)
AMA #796  SAM #188  LSF #020

Offline Mike Anderson

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Re: AIRPLANE SEARCH
« Reply #1 on: February 18, 2009, 08:16:18 PM »
Well, since you haven't had any replies yet, I will start off but mainly to try and elicit others to make some suggestions -  I looked up your motor on the Hacker site and found the following:

Model          Kv     Wgt.     Shaft        Bat.     Const.    Peak             Prop                 Peak
                                                              Current  Current     Recommendation      Power
A30-10XL    900    6.3oz    5.0mm    3-5 LiPo    30A.     70A.      APC-E(12x8-13x6.5)   650 W.

So to me it sounds pretty similar to many of the .35 size setups  that are described in other threads.  I would say that you can plug this motor in to any of the setups currently flying with the Axi's commonly in use here and figure on a 12-6 turning 8-9K as a starting point.  You will need an ESC and most will recommend one of the Castle Phoenix series.

OK, now I'll shut up and let people with better info chime in  -- good luck -- I'll be very curious to hear how this motor ends up working out.

Mike@   AMA 10086
Central Iowa

Offline Mark Scarborough

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Re: AIRPLANE SEARCH
« Reply #2 on: February 18, 2009, 11:01:29 PM »
Floyd,
well, I have the Hacker A30 10XL. It is a functional equivelant of the Axi 2826-10 (though rumor has it that the hacker is underated for power output) From my experiences using the AXI motor, I needed more in the range of a 4200 mah 4s battery to put this motor in a happy place. My plane that I started with was  a Brodak P-40 profile, all up ready to fly it weighed right around 57 or 58 oz. thats on 570 square inches of wing. My power system weighs about 20 oz. I am turning the 12x6 apc E prop. My concern is that to carry yoru powertrain you need at least as much wing as the P-40.  I dont think that you can get away with much less wing area to carry the weight. not sure but I suppose you could turn a smaller prop to get where you want to be battery size wise. I think  that Alan Hahn is flying a nobler on that mah battery he would be one to talk to. His power system is apparantly sized well for that airframe.  I am fairly certain though that his motor is smaller.
if I can help ya with anything else let me know though, look forward to seeing what you come up with Floyd
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Alan Hahn

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Re: AIRPLANE SEARCH
« Reply #3 on: February 19, 2009, 07:47:24 AM »
Floyd,

I agree with Mark that your total system weight is a little too much perhaps for my particular setup---a Nobler, but maybe something just a bit larger than a Nobler, but a little smaller than the Brodak P40 (with its relatively thick wing).  If you could fit the batteries into the Nobler (always and issue that tends to be forgotten about!), I would guess that would put you in the 50-52 oz range.

For specifics, I am flying the TF Nobler Arf, a Scorpion 3020 motor, a Castle Creations Phoenix 35 ESC, a JMP-2 timer, and an FMA 4s2100mAHr Lipo pack. Total up weight is 44oz. My motor weight is 5.5oz and battery is 7.3oz for a total of 12.8oz, about 6oz less than your motor-battery combo.

The plane that comes to mind is the Van Loo Chipmunk---I don't have one, but I have the smaller Sig Super Chipmunk. My main feeling is that you want a wing that isn't super thick (I am not that sure about the Van Loo wing thickness), because then, like Mark says, you might not have enough battery to pull it around for the entire pattern. My Nobler is using a 4s2100 pack that just makes it through a pattern with enough reserve, so you are in between where I am and where Mark is with his 4s4200 pack. There should be something in that size (~40 sized classic stunter?).

I bet you know better than I what is out there in that size.

Offline Crist Rigotti

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Re: AIRPLANE SEARCH
« Reply #4 on: February 19, 2009, 08:18:45 AM »
Alan hit on a very good point.  A JVL Chipmunk wing would work very well.  I think its root is 2 inches and the tip is 1 3/4 high.  I'm at work and don't have the figures in front of me.  I would think a wing of about 575 sq in would be what you're looking for.  Some of the Classic designs are very good for electric because they aren't too thick.  Go with a tail volume of about 25% or more.
Crist
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Offline walterbro

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Re: AIRPLANE SEARCH
« Reply #5 on: February 19, 2009, 03:48:58 PM »
   Floyd
  You will enjoy your flying much more if you use a single battery 4s 3850mah approx.
This way you will only have one battery to charge and most chargers now can balance the cells. Your previous inputs are right on; for wing area 560 to 580 with a 16% or 17% root will fly well . Weight 54 to 58 oz will be OK. an APC e 12x6 is a good start, plan for using governor mode and a 45 amp or more ESC. If you want to use your 3200mah battery you will need to cut down the 12x6 to 11.6 to 11.7 to keep from overloading your battery. You will be using approx 85% of battery power which will give you shorter life and you MUST provide good battery airflow cooling.
Good Luck and happy flying. By the way if you want to fly old time stunt your battery is OK.

Walt
   

Offline FLOYD CARTER

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Re: AIRPLANE SEARCH
« Reply #6 on: February 21, 2009, 02:50:46 PM »
My thanks to all who responded.  I now have a pretty good idea of what will work.  Right now, am thinking of an electric Gee Bee Model D.

Floyd in OR
90 years, but still going (mostly)
AMA #796  SAM #188  LSF #020


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