opjose

Hmmm....


7x5 @ 10.8V / 32A / 15572rpm = 345.6 watts
8x4 @10.5V / 40.1A / 14713rpm = 421 watts
8x6 @ 7V / 31.8A /9685rpm with 2S lipo = 222.6 watts.

"Current range for this motor is 20-43A with a 50A max for 60 seconds."

Assuming 10.8v, and 50A then 10.8v x 50A = 540 watts which corresponds with the motor's maximum ( usually advertized ) rating.


So you have a high KV motor, where a lower KV rating may have worked better for you, to permit the use of a bigger prop.

The 8x4 will produce adecuate power with a max speed of around 50 MPH. All of the other combos result in about the same pitch speed but lower power so the 8x4 is optimum.

I'm running a 9x6 with a 550watt motor, which I purposely propped for long duration flying... e.g. 30+ minutes.

If I switch this out to say an 10x7e I get optimal performance and pitch speed (75+ mph), but I loose duration.

Pistol Pete

well...downloaded motorcalc...something I should have done prior...doh!

no doubt this was not the best choice motor for it...but it will do for now

weekend was too windy to maiden SS...so spent time repairing GP Lancair instead...there is something to say about fiberglass fuselages. well...finally decided to epoxy wings this time...should have could have but finally did it.

Pistol Pete

well...maiden this beauty...goes from stall to over 50mph in a blink of an eye.

now i need a volunteer to take video.[]

new motor mounted with hot glue

had to open firewall some to accomodate lipo and CofG

ESC is under motor at angle for air flow

black cockpit makes panel standout

piece of wood behind motor and below its shaft acts as a stopper for lipo

all studs covered with glue to avoid sharp edges.

enjoy.

opjose

Why not press thos blind nuts in fully?

They will dig into the wood as is?

The mount should be a bit thicker, and at worst you could add a small wooden ring for the blind nuts to dig into, and apply epoxy to this area before squeezing the blind nuts into place.

Hot glue comes off rather easily and will soften on warm days.

Looks like a good setup though.

Pistol Pete

Today took her for a spin...screw came off elev horn...she took a dive from 15ft going at least 30mph. []

Damage report:

Landind wire bent but was straighten out. This area of insertion was beefed with thinned epoxy and most likely reason this area in fuelage did not suffer any damage at all...so good news there.

Right fiberglass boot chipped coating...still usable but will most likely remove for grass landings.

Right wind broke off and wing tip suffered minor damage....and easy repair overall

Right aeleron bent wire and came out with hinges...most likely not enought CA.

Prop broke.

Cowling suffered minor damage.

Motor and mount held like a rock. No damage to motor shaft nor its prop adapter...im definitely happy with this $19 motor.

Blind nuts is what came with motor and used until possible replacement but given this crash...Im definitely leaving as is.

The Micro-plywood firewall was given a coat of thinned epoxy to add strengh...which proved itself in crash.

The piece of wood directly behing motor has a bead of glue...batteries rest right againts it so they have no space to travel forward thus reducing inertia damage.

Photos to follow

Thanks for replies.

BTW...experimented using only one 3S lipo...getting about 10 minutes plus spare for a couple landings. I will kept using only one at a time as i have four packs...good for about an hour of fun.

Anyone using A123 in this plane or similar?

I had a 7S for a heli that is now a 6S and most likely will make into two 3S for this plane as well.

Pistol Pete

Repaired and took for a spin yesterday...LHS only had one prop each...a 7 x 4 and 7 x 5.


Tried the 7 x 4 first as it was ready for shaft and despite motorcalcs recommendation just did not cut it. It was loud by comparison and landings were fast and long. Will try out 7 x 5 today. Eventually will work towards an 8 x 5.

Thought I shared some repair photos as a before and after effect.

Used carbon fiber rods and epoxy for added strenght.

Pistol Pete

Ready to go...

Towerhobbies red skin was just a tiny tad lighter but it is only noticeable to the purist.

opjose

Great job on the repairs!

Bobet

You did a really good job fixing it.

Pistol Pete

thanks guys...

BTW...the 1700Kv motor is happy with the 7 x 5...looks small given the size of plane but who can tell when its spinning or when up in the air?

triboyeric

hello,

I am interested in converting this plane to brushless. I have a 1064kv Scorpion 3014-18, is that too much power? running on a 3s 2200 mah lipo and using a 45 amp ESC+seperate RX battery. If this is all possible, what prop size should I use??


Eric

Pistol Pete

For that size motor I would go with either a 8X5 or 8X6.

I used this link to get an approximation for my needs:

http://brantuas.com/ezcalc/dma1.asp

You can also download "THE" motor calculator for a FREE 30 day trial at:

http://motocalc.com

dont forget to download latest DATA for it once up and running.

I wish I had prior to my inexpensive motor purchase route.

Mine is down after another crash...yikes...pending repairs.[X(]

opjose

That motor is fine... however you'll be pulling an easy 20C with it. ( I'd go ahead and use a 9x6 prop for a bit more power... )...

That means your batteries will tend to sag under load, so it will not produce full output unless you go with 30C batteries....

You are better off running two 2200 LiPo's in parallel.

Combined the run time will double but the packs will handle the load w/o sagging.

You end up with the same overall run time, 20+ minutes, but much better performance at higher throttle than a single pack, and your batteries will last longer and be less stressed.

You'll love it this way.

triboyeric

Okay, could I use the stock motor with my 45 amp ESC and my 2200 lipo?

opjose

The "stock" motor is a brushed motor, so you could not use your ESC with it.

You CAN use LiPo's with the stock motor and the stock ESC, if you flip the 3 position jumper on the ESC to the other position.

However WHY bother?

The motor and ESC combo you are thinking of is perfectly fine!

Just run the two batteries in PARALLEL... you can buy a pre-wired adapter for about 4.00 from Tower... and you can always use the batteries without the adapter.

I would advise you to use the motor and ESC you are thinking of with the batteries in parallel.

You'll love the performance of the plane this way...

Two LiPo's sit side by side within the fuselage w/o any modifications... see my Gallery for a picture of the SS EP parallel setup.

triboyeric

Okay,

I might go with the parallel then, what prop size for a combination of power and around 20 minutes of flight?

So 20 minutes of flight time seems like a good deal, but what about aerobatic capabilities??? What maneuvers can you pull off with that kind of setup?

Eric

opjose

Use a 9x6E APC prop with your motor and ESC.

You'll get excellent flight times ( 20+ minutes ) and fantastic performance.

The comments I get with a similiar setup...

"Gee that flys like it has a .40 engine in it!"

You'll be able to do any aerobatic manouver the airframe is capable of, including a few it isn't really designed for, such as prop hangs...

It will not do 3D though, because it is not a 3D plane, but short of that, it's one heck of a flyer equipped this way.

triboyeric

Okay will do that then. Know of anybody selling a used SS EP???

Eric

opjose

I don't know of anyone who would part with one!

triboyeric

I know!!! It seems like New is the only way I'm gonna get one. Good looking plane!

eric

guapoman2000

Hi guys!

Super Sportster EP major Maintenance:

This model has been in a corner of my Master Bedroom for almost one year and finally came around to it super early this morning and worked on it for a little over 2 hours. I found and fixed numerous items which included:

1. No motor, and decided to install my HIMAX HA3630-1000 (1000 Kv) and using my large Castle Creations Phoenix 45-AMP ESC and using E-Flight-max 3-Cell, 2200mAH, 25c discharge, Li-POLY batteries.


2. Observed that the Elevator Servo (Hitec HS-81 Standard) was completely free wheeling (nylon gear striped) so, I took it out and replaced it with a Hitec HS-81MG (Metal Gear).

3. Since this model was involved in a previous hard nose crash that resulted in the replacement of the wing assemblies I had to double up the Plywood Firewall using the wood railings from another identical model that I found crashed in the RC Club years ago. This made for a very strong motor mount assembly and all I had to do was to Epoxy a few areas for additional strength and all turned out very good. The cowling re-fit resulted in a tight fit such that I resorted to cut away a V-Shape section from underneath the cowling and this resulted in a better fix of the Cowling.

4. Took out a brand new Master Airscrew “Wooden” 10 X 7 propeller with yellow tips and installed on propeller adapter.

Flight Summary:
Before I used to fly this model with a high 1350 Kv motor and required to use some large and heavy 3-Cell, 5000mAH, 12C, Li-POLYs and resulted a very heavy model.

Now the Center-Of-Gravity was picture perfect and not so much nose heavy and take off was very scale and leveled. It was surprisingly very fast as I believe that the lower Kv motor has much more torque to swing the 10-inch diameter propeller. I was able to fly for two flights using the E-Flightmax 3-Cell, 2200mAH, 25C, Li-POLYs.

The model was commanded to perform Cuban-8’s, inverted flights, scale, slow and smooth rolls from any rotational direction and the best hammer heads within my fleet of RC Models!

I am very happy!

guapoman2000

Thanks to Geraldo Rivera for these fantastic Pictures!



Right Before Take-Off


Picture Perfect Take-Off


Zooming around









Model performs the best Hammer Heads!!!

opjose

Yeah I've seen this mistake made on many a plane... including some of my own...

On a static test your prop RPM's on a direct drive should be, what, around 80% of the motors KV rating x supply voltage under load?

If more than 80%, give the plane a bigger prop or more pitch... if under 80% go smaller.

That gives it 20% to unload with in flight, while not overtaxing the motor.



I picked up one of the newer "Snoopy" Sportster EP's and added a Turnigy 800w motor for blistering performance...





A very nice plane!

guapoman2000

opjose,

I have never come across anyone expressing an Electrical (Motor) Power system with your posted equations as noted above.

My Himax HB3630-1000 inrunner has 1089Kv but, you need to include the other important motor parameters such as the Internal Resistance and No Load Current rated usually at 10 Volts Direct Current (DC).

My Motor Parameters are found at:
http://www.maxxprod.com/pdf/HB3630-xx00.pdf

HB3630-1000 motor:
Kv = 1089,
Rm = .050 Ohms,
Io = 1.1 Amps,
Efficient Operating Current = 15-30A
Power(Max): 600 Watts

I am using a Wooden Master Airscrew "Glow" 10 X 7 and the model zooms along at 1/2 throttle "and" for spirited flight with manuevers all I need is two (2) Clicks above 1/2 Throttle.

I have not measured my AMP draw as of yet but, the on-line estimator that I use is right at 28 AMPs (~300 Watts) so, I am within the useful efficiency of the motor and in my case 79% efficiency at wide open.

My model's E-Flightmax 3-Cell, 2200mAH, 25C discharge, Li-POLYs come out luke warm to cool depending on my throttle management and I place my flight timer to nothing over 6 minutes and the packs measure 11.3 Volts after every flight. Sure, I can fly with larger capacity packs but, my goal this time around is to keep things light.

I am happy with this "new" setup for my GP Super Sportster EP as before I had a motor with too high Kv and most of the energy went to heat.

Regards,
Carlos[8D]

guapoman2000

For those that like that Wooden Master Airscrew 10 X 7 (Glow or Electric) then, you can purchase it from:

http://www.bphobbies.com/view.asp?id...53&pid=MA06110