old4570's blog View Details
Archive for October, 2019
Posted by old4570 | Oct 29, 2019 @ 08:54 PM | 2,554 Views
Continues from Part 2

So I have verified RPM / Current Draw / Thrust to my satisfaction .
And I am happy to trust the V3 stand to report the truth to me . ( well , as close as it can )
This is not a laboratory grade instrument , but the results are consistent / repeatable / and ball park enough to be very useful .

So exactly what can the V3 test stand do ?

Power Meter

If you watched the video in part 2 ?

Battery - You can see the voltage sag under load ! , as well the current supplied . Did anyone think that perhaps you could use the test stand to TEST your battery pack ? I see plenty of posts on RCG where people ask questions or complain about their batteries . How hard would it be to replicate the conditions your battery has to put up with and then actually see in real time what the pack is doing !
That's are far as I'm getting into batteries - because it's a can of worms ! and we are talking V3 test stand right now .

Motor - There is a saying , a chain is only as strong as it's weakest link . And we can expand on that to = A quad racer is only as fast as it's slowest engine .
With a test stand , you could test your motors for the weak link .

ANd Thrust

Propeller - This is unfortunately not as uncomplicated as it should be .. Unless you use a large enough motor with a high enough KV so that all propellers can be tested with as little induced variable as possible .
This is why we need constants ..
The motor...Continue Reading
Posted by old4570 | Oct 28, 2019 @ 11:28 PM | 2,581 Views
Turnigy V3 thrust stand .. (1 min 57 sec)

Quick and dirty video showing the thrust stand in use ...

I checked the thrust results :

The way I did it was the cheap nasty and EASY way .
I have digital scales , so I just powered up the test stand , powered up the scales .
Zeroed the scales , and then applied the scales directly to the test stand ..

Then I could compare both digital read outs ..
This is by no means laboratory accurate , but as near as I could tell the test stand was replicating the force from the digital scales .

So the test stand looks to give real world results .



Part 3
Posted by old4570 | Oct 27, 2019 @ 10:38 PM | 2,406 Views
PART 1 ( of many many parts )

At last a motor is here !
Be a budget 2204 / 2300kv 2-3s ( 12A - 120W - 14 pole )

The very first thing I wanted to check was RPM accuracy as I had seen a complaint or two about this !
Now the very first thing anyone has to understand is :
You have to input the correct pole count for your motor !!! or you will get the wrong RPM read out .
This motor is 14 pole ( advertised as ) .

Setting the test stand to 14 pole :
setting motor speed to 10,000rpm as reported by the test stand
My GT power tacho reported some 9200rpm .. ( 3 blade mode as it was a 3 blade prop )
So where is the discrepancy ? With one or the other or in between ?
I would suggest the read outs are close enough to make any data viable and usable .

The prop was not well balanced .
The test stand being metal , means quite a bit of vibration against a hard surface ( table top ) . ( yeah , balance the prop )
So this is all I have done ..
Mounted the motor , connect things up , and do a quick test run checking RPM ..
Next I will have to check that current draw reading .. ( And balance the prop )

AMPs Test :

I just checked , and the AMPs look to be good ..
So it looks like I can trust the current draw reported by the test stand ..
I threw a 4 blade on as it runs much smoother ..
So I can definitely do some RPM / Watt's / @ RPM range / Thrust - tests ....

So I guess I will have to do some thrust accuracy testing now ..

Posted by old4570 | Oct 27, 2019 @ 04:53 PM | 1,860 Views

Maybe not quite that bad ( To hell and back ) ..
I cut down that 3025 and just had to see how it changed things ( 2725 ) , I mean I was getting more RPM .

Off I went , it was overcast and then the sun came out driving up the humidity !

By the the time I got to the football field it was fully humid ( This be bad for me ) and I was sweating ( more bad )
Sweat seems to attract flies , and I got me some half dozen or so once I started flying ( both hands on the Tx )

So there I was flying with half a dozen flies crawling over my face .. The stress was monumental ( I despise flies ) ...
I was forced to make two emergency landings ( power off crashes ) to swat the flies away as I could no longer stand it .
It was so bad my fingers were a quiver on the Tx as the flies crawled on my face .
Not being able to shoo them away was so gawd awful ..

Oh yeah , the 450x was undamaged , they be so light that once you cut power it's very hard to damage them . ( I really like that ) .
And the cut down prop , I don't know ? Was it the flies , or is the 450x actually flying faster ..
I will post a short video soon .

450x with a cut down prop (0 min 44 sec)

Once airborne , I cut the throttle back down bellow 50% , take off throttle is around 70%
Posted by old4570 | Oct 24, 2019 @ 06:28 PM | 3,238 Views
Wow ...

What a huge difference KV makes to peak current ..
These small motors are teaching me something .

1103 7800kv 19000rpm @ 3A ( 50% throttle ) Peak current over 7A ( 3025 prop )
7800kv x 8v = 62,000 RPM ..
Obviously the motor is horrendously over propped .
And when the motor is operating outside its Current / RPM range it converts energy to heat ( everyone knows that )
But still , over 7A peak current for such a small motor .

1104 4000kv 22000rpm @ 2.3A ( 100% throttle ) 3025 prop .
That is just a huge difference ..

I am not prepared to run the 1103 long enough to get a steady RPM reading , last time I did that I cooked the motor .
So I cut the prop down :
3025 cut down to 2725
@ 3A current draw rpm is now 23000+
At 50% throttle current is down to 2.6A
Prop was perfectly balanced , and I have no more props ( 3025 ) to play with ( to cut down ) ..
I have some 3020 on order .. ( ? when they get here )
The 1103 have a high kv for that 1s operation , so while it's a cute motor ! It may not be the best motor choice for the 450x wing .

The ESC in the 450x wing is equipped with a plug , so swapping motors should be relatively simple and painless .
For now I will keep going with the 1103 and try out some more props and see how it goes ..
There should be a 1105 and a 1106 on the way .. ( 1105 is 5000kv )
That 1105 is the motor meant for the 450x wing .. And I just had to go 1103 ( Silly boy )
Posted by old4570 | Oct 23, 2019 @ 11:45 PM | 2,922 Views
1104 4000kv from Feebay ...

Came at last :

Quick test =

1s battery ESC combo = 10400 RPM with the 3.8x3 prop
2s battery = 15600 RPM with the 3.8x3 prop

4000kv x 4 volts = 16000 RPM
4000kv x 8v = 32000 RPM

Hmmm , motor ran cool enough on 1s , and I think it should take more prop ..
On 2s it seemed to be maxing out near 3A for that 15600 RPM ...
Now the earlier 1103 that I cooked needed about 7A to pull this RPM with the same prop . ( Cut down prop )
Same prop = 17100 RPM @ 6.4A , cut down prop hit 19500 RPM around 7A and then the motor cooked !

The ESC used is the one out of my MG800 , and at full throttle the motor was cutting .. This was the issue with the ESC when it was in the MG800 .
So looks to be a faulty ESC , @ 3A in anyways .. Bellow 3A it seems to run fine .
Motor starts to warm around 2.5A ..

I dont know if this is a 1s / 2s motor or a 2s / 3s motor ?
Runs well enough 1s , but lacks thrust ..
So just might see how much prop I can put on it !

2s there is plenty of thrust ..
I put a plug on it so I can swap it around ( ESC's ) and I can put it in the 450x wing as the 1103 is also plugged .
Just ordered some new ESC's as the 2s one is faulty .. So will replace it ASAP

3x2.5 Prop ( 3025 )

2s ...

21700 RPM with a peak RPM of 22000 @ 2.24A with a peak Amp's of 2.3A ( Motor stayed relatively cool )
Posted by old4570 | Oct 22, 2019 @ 06:01 PM | 3,197 Views
FF Bird -
Wind has backed off , and so I tried the bird again ..
Need to tweak the foam a bit ( TE of the wings ) and it glides really well .
I was playing with it in the front yard and once tweaked it glides with very little altitude loss .

3025 Prop and 1103 - ( 450x )
Went to the park ( sink hole ) and gave it a fly ..
For launch more power is needed to get some thrust for that much needed momentum .
@ 50% throttle the 450x was struggling .. At around 75% throttle it launched very cleanly .
Once in the air and moving I was able to back the throttle to around 30% give or take some and still maintain decent speed .
I was expecting more noise , but no . Turned out to be reasonably quiet .
So this combo might fly @ 1A , I might try some throttle pre sets ( 3 position switch ) and lock the throttle at 1A and see .
I think I want a prop with more thrust though . The 3.8x3 is good , but might just load the motor too much even though the data sheet says it would be operating withing acceptable parameters . ( Cough / Cough )

Thrust Test Stand -
Waiting on motors , the motor I want to mount for prop testing is a 1106 ..
Also have a 220? on the way for larger props .
Just waiting for the stuff I ordered ( Painful ) , there are tests I want to do .

FF SU-27 -
Oh man ! This thing does not like the wind at all .
Even puffy breeze is enough to upset it .
Probably best indoors .

Yeah ! Waiting on stuff ..
Always waiting .. A watched pot never boils ?
I want my stuff !

Posted by old4570 | Oct 19, 2019 @ 09:27 PM | 3,486 Views
FF Bird from eeBay (0 min 56 sec)

Was on Feebay and saw this 2 Pack of FF Birds (?)
So , the first thing to come to mind was = Can I RC it ?

Well , first things first ..
It's windy , really windy .
So nothing small is going to glide well , especially something funky like a FF Bird .
I had to try though ..

So I was able to make the bird glide across the back yard , not really sure I want to bother RC'ing it !
Not really that good !

Might make for a fun chucky , but for how long it will be interesting ?

Certainly needs some trim to get it to glide , usual rules apply !
Posted by old4570 | Oct 17, 2019 @ 11:30 PM | 2,101 Views
I know , I said I was done with the 1103 .... But it's such a cute motor !

RCX 1103 7800kv ( 2 - 3 s )

If you look at the data sheet , well it say's the motor will do 10A and over 100 Watt .
I am highly dubious .

My first 1103 was DOA
My second , well I cooked that motor testing a cut down prop . ( around 7A )

I got some 3025 props with the motor .
Motor is installed in the 450x micro wing .
With the 3025 prop amps is a little north of 7A 2s( again )
The motor gets hot , the motor wires get hot ..
I only ran 100% throttle for about 3 seconds , which was enough for substantial warmth .

2s test :

At 1A I recorded some 12,000+ rpm
At 2A I recorded some 16,000+ rpm
And at 3A I recorded some 19,000+ rpm
With the 3025 prop .
3A is right around 50% throttle ( Physically on the Tx )
And at 3A current the motor wires are getting warm ..
Not sure how anyone would rate this motor size 10A ?
I would suggest half that as something to avoid continuously .

Anyhows , blowing a gale outside right now 40kmh with wind gusts over 70kmh

Will take the 450x out ASAP ( as the wind allows ) , really want to try out that 3025 prop ..
Must remember to limit myself to about 50% throttle .
Posted by old4570 | Oct 15, 2019 @ 12:38 AM | 2,303 Views
Free Flight SU-27 found on Feebay ..
With discount , cost around $5 USD or less .

Wow ! Came fully bent in the post ( see pictures ) ..

But it was an opportunity to test some ideas I had .
Got out the old clothing iron , bumped the temp to 80deg C and proceeded to iron out the wrinkles .
Nope , not doing a good job !
Bumped the temp to about 120deg C and I was just starting to melt the foam ..
At just over 90deg C the iron was doing a half decent job .
I had 2 layers of house hold paper between the foam and the iron at all times .

But there was a lot of bent to go around .
The motor had got bent as well and would not straighten out .
So I had to cyno it reasonably straight .

Assembling !

So the parts have these little tabs that get pushed thru holes .
The foam is SOFT , I mean soft .
Best to use needle nose pliers , very carefully push the pliers into the hole and just barely thru ..
Grab hold the TAB , and pull it thru ..
Much easier than trying to push the tabs thru the very small tight holes .

Once assembled .. Its not overly bad !
CG looks to be about right , and you just need to tweak the control surfaces for a decent glide .
It's windy outside , so the SU 27 glides like a tissue ..
Really need some UBER low wind ( no wind ) or possibly a decent indoor space .

Free Flight Micro Capacitor Powered SU27 (1 min 3 sec)

Was windy yesterday ..
This morning was calm , but a slight drizzle ..
Oh that weather !
Posted by old4570 | Oct 11, 2019 @ 05:44 PM | 2,335 Views
Sorry - re upping as Utube ruined the video ..
Re - encoded with handbreak - Hopefully Utube wont ruin it ?

HobbyKing Micro SU27 (8 min 4 sec)

I woke up 6.30am and looked out the window ..

I was encouraged by what I saw = Nothing ! Not a puff of air !
Got dressed and walked to the Park / Football field ..

6 axis flight control was OFF ! ( No stability control )
Rates are still 50% with no expo .
Seriously , this flight was with like 5mm to 10mm of stick throw = IF THAT !
The micro SU27 is super responsive , and it is also so - WAY Stable .. ( I have that forward CG with the 300mAh Nanotech 2s )
Rates could come down or a decent chunk of expo added .

But the flying conditions were perfect ( No wind / no breeze / nothing )

Seriously , with maybe 25% rates and maybe 25% expo , this could be a NOOB plane when there is no wind .
All of that flight is maybe 50% throttle , around half way I cut the throttle back more .

That battery plug takes a beating on landing , can't be helped .

I know you guys don't like watching video , but if you are interested in this Micro SU27 , you want to watch the video ..

Posted by old4570 | Oct 09, 2019 @ 07:54 PM | 2,275 Views


A true micro Mustang ..
I thought the SU27 was interesting ..
Now Banggood has a midget ( micro ) Mustang ...

Small mustangs have been done before , and they actually seemed to fly ok .
So how will this one go ?
Posted by old4570 | Oct 07, 2019 @ 01:02 AM | 2,030 Views

This be the FrSky version ... PITA ...
And yes it was a pain in the abacus .


Oh dear ! , it just did not want to bind properly . Just kept giving issues and refused to calibrate the gyro .
The short of it is ! You need to fine tune the frequency .
I tried negative and things went worse , So I went positive in the fine tune and things got better .. Currently +20 on the frequency tune .


Yeah , those 180mAh batteries ? Not available when I ordered the SU27 .
300mAh battery ?
HK does sell 2 300mAh 2s batteries , one is 17 grams and the other 19 grams .. The bat for the SU27 is 14 grams ( listed )
The actual weight of my 300 is 16.2 grams ( my scales )
I had to cut the slot in the fuse to move my battery further back .. You get maybe 5mm before you hit the buried Rx ( Be careful )


See pictures .. The CG with my battery is an estimation , but CHUCKING the SU27 = Sort of nose dives - gently .
I may need to lead the tail .


Seriously a lot of throw ? I set my rates to 50% to start , still a lot . But with the forward CG ?

Flying weight will be 43 grams with the 300mAh battery - factory sheet says 39 grams with the 180 ..

And thats where I am for now ..

Maiden Update

Before leaving for the park , I calibrated the Gyro per instructions ( nose raised 10 degrees ) .
This was not enough . In stability mode the Su27 hunted the ground .. ( gently in forward flight and more harshly in...Continue Reading
Posted by old4570 | Oct 05, 2019 @ 09:18 PM | 1,678 Views
Hmmm ..

Fixed the R4 Depron HLG ..
Took the R4 to the park , was very average . I could see this glider working on a slope though = Really well !

Stuff !
Hmmm , yeah lost the plot and the budget ..

2204 2300kv
1106 6000kv
1105 5000kv
1104 4000kv
1103 7800kv
1410 3500kv
0905 10,000kv
8520 41000rpm
10x15 28000rpm
10x20 32000rpm ( ? on voltage )

Nope , not a wish list ! ( I wish it was a wish list )
Hmmm , Blocking Diode ...
Want to use solar without a bunch of stuff = Blocking Diode !

Yeah , the more I look into this , the easier it might be to do . Just need a blocking diode to stop the solar cells from sucking juice out of the battery .
So as long as the battery voltage is higher than the voltage put out by the solar cells , you need a blocking diode .
Once the battery voltage drops bellow the solar voltage , current will flow into the battery / and motor .
Posted by old4570 | Oct 03, 2019 @ 10:38 PM | 1,547 Views

Switches came today !

A) Yes , I have to add a switch
1) So I dont need to remove the batteries all the time
2) Tach does suffer parasitic drain
3) Isolate the batteries from the parasitic drain

I cut the negative wire , and soldered the switch into the circuit .
I glued the switch ( hot glue ) and then proceeded to cover the back of the switch in glue to protect the wires .
Hope is to never need to mess with this tach again .
Besides clicking the switch and charging the batteries . As it should be !

Yes , the hot glue job is a little ugly - but functional .

Bushleague Modz ( GT POWER Tach to AAA ) (2 min 34 sec)

It's raining outside , so I made a video !