55% Mini Racer, Weekender ? Need your inpouts

[Guy]

The ailerons look about right for the size of the wing. The faster it flies, the less control movement is needed.

HobbyKing recommends an 8040 or 7035 for the 2204-14T, so a 6x4 may be a little small for 2S. On the other hand, it'll certainly help keep the current draw down on 3S.

It sounds like you're going through a similar learning curve to me. I did a lot of research, ordered a bunch of stuff and it's still sitting in my parts bins today.

Don't get discouraged. The lessons I've learned along the way were well worth the extra hardware in the end--and I'll find a home for it at some point. The whole community here is very helpful and encouraging, so if I can't help you there will be someone else who can.

With that said, what can I do to help?

Sorry friend--not even on the same continent. I live in Ashcroft, BC Canada.

I recently extended my cold-weather flying down to -15C. I ordered the Turnigy Transmitter Glove and HobbyKing Universal Heater system. It works great on the 2S 2200mAh batteries I have, but only lasts about 15 minutes before the low voltage alarm I place on the balance lead goes off. It's enough time to walk to or from work (I usually fly one of my Old Fogey's to/from work). It has however, been windy enough to ground me this past week. I'm starting to make headway on other projects, so it's been a good thing.

Cheers!
Randall

Hello Randall

I thank you for your help.

I am going to check the comments on this thread and try to order a new power system for my project. Also, i am about to order the recommended props because even if they do not work on this project, they will be useful for the next one.

Ill keep this thread fed with my experiences.

Concerning your heating gloves, i suggest you built a harness so you can have two batteries paralleled. This will eventually double your heating time ;-)

This is something i had to do for my Align Trex 500 to get enough flight time.

Guy

 

[randall_l]

Thanks for the suggestion Guy. I've made several series and parallel adapters for RC over the past couple years.

I had considered connecting 2 batteries in parallel, but the Turnigy Transmitter Glove isn't really meant to carry such weight. It's already strained with the heating unit and one battery. I had to make an S hook to take some of the strain from the glove where my neck strap goes through top on its way to the radio.

I've been tossing around the idea of integrating a tray into the mix--having the glove just surround the tray (holding the heating unit, radio and whatever else I feel the need to put in it.

Cheers!
Randall

 

[Guy]

Thanks for the suggestion Guy. I've made several series and parallel adapters for RC over the past couple years.

I had considered connecting 2 batteries in parallel, but the Turnigy Transmitter Glove isn't really meant to carry such weight. It's already strained with the heating unit and one battery. I had to make an S hook to take some of the strain from the glove where my neck strap goes through top on its way to the radio.

I've been tossing around the idea of integrating a tray into the mix--having the glove just surround the tray (holding the heating unit, radio and whatever else I feel the need to put in it.

Cheers!
Randall

Hi Randall

You could maybe try to have the batteries in your pocket, having like 50cm wires long so the battery pack could be moved out of the initial place to go on your belt, like a mobile phone holder.

Concerning my project, i ordered the same gears as your 3s pack.

Are you happy with the Turnigy Sk3 serie so far ? I am waiting for those to come to update this thread, praying for this to work

Concerning the turnigy 2204-14 and the eflight park 180 (that one was pricey) i think i will built some indoor models because i don t know if they can handle outside winds.

I still have to try those with the recommended propellers i am still waiting for though.

Now is not the moment i prefer : waiting for the gears to come...

Best. Guy.

 

[randall_l]

I've only owned the 2122-2100 from the SK3 series, but I'm very satisfied with that model.

My first one survived several dirt naps before finally being done in by a nose-in to concrete, destroying the bearings. The one in my 3S pod has over 400 hours on it so far.

I haven't measured the thrust from the Turnigy Sport prop (TGS 6x4) yet, but the metal bushing that comes with the motor is the perfect size for them. There's no slop and the O-rings aren't stretched as much as with the APC style props.

Plus, getting 436g+ thrust from a power pod that weighs 118g (including battery, ESC, volt meter, 2x servos and receiver) is great.

I know what you mean about waiting for orders. I've got one coming with parts for the HobbyKing Versus I've been building. Time seems to move slow.

At least it's given me time to work on other projects. I've completed a swappable FT F-22 and a scaled down Alula (500mm wingspan) with swappable glider/motor pods. Now I'm converting plans to swappable for a Bugatti 100p.

Cheers!
Randall

 

[Guy]

I've only owned the 2122-2100 from the SK3 series, but I'm very satisfied with that model.

My first one survived several dirt naps before finally being done in by a nose-in to concrete, destroying the bearings. The one in my 3S pod has over 400 hours on it so far.

I haven't measured the thrust from the Turnigy Sport prop (TGS 6x4) yet, but the metal bushing that comes with the motor is the perfect size for them. There's no slop and the O-rings aren't stretched as much as with the APC style props.

Plus, getting 436g+ thrust from a power pod that weighs 118g (including battery, ESC, volt meter, 2x servos and receiver) is great.

I know what you mean about waiting for orders. I've got one coming with parts for the HobbyKing Versus I've been building. Time seems to move slow.

At least it's given me time to work on other projects. I've completed a swappable FT F-22 and a scaled down Alula (500mm wingspan) with swappable glider/motor pods. Now I'm converting plans to swappable for a Bugatti 100p.

Cheers!
Randall

Hello,

I have ordered 2122-2100 from the SK3 before your last post, still waiting for this to come - i went for the APC 6x4 props on this order and i just hope they will do for test phase when the gears will be mounted.

I have no doubt i will brake a fair amount of props before i found out the right settings for the little bird though ;-) So i'll then give a try to the TGS as you suggested ;-)

Did you built a trust mesuring system so you can get the trust of your gears ?

I wonder if i am not going to built one myself while waiting for the gears to come...

Other question: Do you have plans for the Alula project ? and what kind of foam did you use ?

(Note for readers: I will not lost the main subject of my post in this - though this is interesting stuff ;-) )

Best. Guy

Guy

 

[randall_l]

As you fly, you'll crash less. I've only been at it for 2.5 years. I crashed a lot at first, but now I can go months of every-day flying between crashes. Even at that, the recent crashes have all been with unfamiliar aircraft (FanJet trainer--never flown an EDF before, swappable FunJet--never flown a rear-mount pusher or canard before, KFmDavidWing--never flown a wing before).

I have a really basic thrust measuring system. It's somehwere in my work area that I can't locate at the moment. It's basically a pyramid that I mount the power pod in and weight it down with a 1kg weight and put on a postage scale (2kg capacity). I record the starting weight, increase throttle to full and record that weight. Starting weight - WOT weight = Thrust. It's probably not very accurate, but it gets me in an acceptable range.

I've started building a balance-type thrust rig that I can just put my digital scale under and measure that way, but it's been a busy couple weeks.

For the Alula, I used the plan from this thread on RCGroups. I had to modify the pod to get my gear to fit and add some weight in the glider pod (will have to add more as it's tail heavy). I took some video with the motor pod on my iPhone. I'll put it on my YouTube channel when I can.

Cheers!
Randall

 

[randall_l]

I finished my balance-type scale. The first run, I stopped at 75% throttle because I was using a servo tester and--being right in front of the setup--was in harms way. I fitted a receiver, set up a camera to do a sequence of pictures and stepped away for the following tests--just in case something went wrong.


Ignore the mess--I've got 3 projects on the go right now so there's a little clutter.

Motor: Turnigy SK2 2122-2100kv Brushless
ESC: Turnigy Plush 12A (2A BEC)
Battery: Zippy Compact 3S 500mAh 25C LiPo

Prop 1: Turnigy Sport (TGS) 6x4 - Thrust: 706g (average of 3 runs)
Prop 2: APC style 6x4 - Thrust: 663g (average of 3 runs)

My results caused some doubt as previously, I only measured 436g from the same electronics and APC style 6x4 prop. So, I went back to the postal scale (still can't find the pod pyramid--must be in the junk closet) and tested with a weight set. It's not accurate at all between 200g and 1kg. That'll teach me to scavenge measuring equipment. Where I work was throwing it out a couple years ago--and now I know why.

Then, I tested the new setup with the same weight set and added a pulley/string to get the same motion. It's out by 1.1g g at 1kg, which is totally acceptable and much better than the postal scale.

I measured the 3S pod again on the new system with both props and got roughly the same average (+/- 0.2g). So a whopping 706g of thrust for my heaviest so far swappable (P-51D Mustang) at 220g AUW--yikes! That also explains (more reasonably) how my MiG-7 (180g AUW) got to 93kph. I may even be able to break 100kph with the TGS Sport prop.

Now I get to re-measure all my power setups--I'll post the results on my RCGroups blog. At least I was getting more thrust than previously measured instead of less. the postal scale is headed once again where it was destined for a couple years ago--the recyclers.

Cheers!
Randall

 

[Guy]

Proper trust.

Very nice built Sir Randall, you have my respects.

Good news on my side of the planet. This message is a quick update to let people know i did receive my gears.
Propellers, motors and stuff so i plan on doing some "homework" this we so i will update this thread properly.

And maybe if i found the proper combination, have my miniracer flying in the air. with a nice video for you guys.

Next step for me is to built a trust measuring system. Then check again the watts drowned so i do not burn the things and then go fly.

Do you guys know what is the proper trust number for a given weight ?
I mean if i know the weight of my plane (lets say 200 gr), if i want it to fly, i need more than 200gr of trust but how much ?

The answer to this question will depend on the type of plane i am flying i assume. So i think i can have the miniracer as a pilon racer.

Thank you all for your help.

Guy

 

[randall_l]

Thanks for the compliment Guy.

Have a look at this thread: http://forum.flitetest.com/showthread.php?5102-Thrust-vs-Power-to-Weight-Ratios-for-Prop-Planes

The following is only my opinion on thrust-to-weigh ratios...

Trainer: 0.8:1
Sport: 1.2:1
Aerobatic: 1.8:1
3D: 2.5:1
Racer: 3+:1

This coming from someone who's trainer is 1.7:1 (284g 2S pod) and who's warbirds and racers are currently around 3.8:1 (706g 3S pod) these are both static thrust.

The initial thrust data is up on my RCGroups blog: http://www.rcgroups.com/forums/member.php?u=362109

Cheers!
Randall

 

[Guy]

V E R Y N I C E Sir Randall

here are some of the last pics of the plane with the Turnigy SK3 2100kv with 3s and the 10A Turnigy ESC.

I clearly follow your path installing this setup with a APC 6*4 prop.



As you can see the plane got beat up by previous tests with less powerful setups
When i'll have the correct setup, i'll built an other one with clean paint like my full size spit called "COOL-DOG"
-> airbrushed




Tested the miniracer with the wattmeter, this setup is W A Y beyond the Turnigy 2204-14/10 plush ESC/GWS EP-7085 prop, here are the results



If you check the motor characteristics, the watts are too much, and too much amps also for the plush

so i decided to mess with the upper endpoint of the throttle channel on the radio so i can control the thunder. instead of giving 100% up throttle i am now around 50% up



This is much better, and i can say the ESC is warm only cause first i had to mount it outside of the fuselage so it can get some fresh air from the propeller.

Note: on my final plane, it will be inside.

I need to test that on a calm day, if this is not enough power, i will allow more amps to go through by changing the endpoint on the radio.

I don't know if this is a good way to control a power system but it seems to work on the bench (see the readings on the wattmeter).

I still need to built a thrust system, didn't have time for that as i have just finished two other projects scratchbuilt

Tricopter
V-tail quad copter

Very interesting thoughts and tests on your blog Randall - did you check the Watts drained or just the thrust ?

 

[randall_l]

Good work Guy. A little bit of airframe wear is all part of the learning curve.

Don't worry too much about overloading the motor with the 6x4 prop unless you are heavy on the throttle. A 12A ESC would be a better match for the SK3 2100kv. If you are concerned, you could go down in size to a 5x3 or 5x5 prop.

My MiG-7 seldom goes over 60% throttle. A 660mm plane travelling at over 90kph gets small very fast. The Turnigy Sport 6x4E prop should get me closer to 100kph. I'm also sourcing parts for a 4S pod to give me upwards of 900g thrust--I guess I just want to see how far I can take it.

You may need to order some thicker bands to keep the prop on at high speeds (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=8234). I went through the 3 that were included in my first 3 flights--and lost 2 props along the way.

Cheers!
Randall

 

[OrangutangSurfer]

Guy,

this looks really cool I like the mini plane idea, you're right about the cost vs. size thing i mini plane for a few bucks would be awesome. I hope you get it to fly well, I've thought about trying the same thing but I've only heard success in the 70-80% size range (from original size FT planes that is).

good luck!

-Jes

 

[Guy]

Hi every one !

Sorry i didn t update this thread correctly, i owe you guys the reasons:

Very bad weather for a long time - a new baby in the family ;-) - I built myself a workbench since i didn t have enough place to work on.

I will update this since i have all the gears, i just have no time right now (but the weather is great now!!).

I thank every one for their help. A BIG thank to Randall who helped me so much for the gears.

I ll let you know what is going on, success or failures, and i ll try to videotape everything.

Guy

Guy

 

[Guy]

Hi FT Family
I just came back from the field and this experience is still a failure for me.
As bad as it can be.

The Mini Racer i built has been tested today with a Turnigy SK3 2122 2100 Kv and a GWS 7053 propeller. The ESC is a stock Tutnigy 10A and the battery a ZIPPY 3S 500mA

I have already built 3 noses for this plane since it likes the ground so much ;-)

I have to say, this is my first failure in scratch builds.
And it hit hard.

So far everything i built flew like a bird

2 SpitFires
3 Vtail quads
http://vimeo.com/guyatek/guyateks-flying-built-part-1
1 Tricopter
You can also found the built and flight test on my vimeo channel GuyaTek
1 Mustang from FIlken
http://flitetest.com/articles/p-51-swappable-with-plans
5 FT Versa
2 FT Duster
2 FT Racers -yet to fly
1 FT P51 Yet to fly, you can follow the full built on My Vimeo
http://vimeo.com/guyatek/part1printingplansandbanderoles
This one is on going right now and i am posting on video everything from printing to flying
1 MiCkey RC PilonRacer that i had mod - I'll post a Video on Vimeo ;-)
1 FT VIGGEN EDF Version
And so on...


Everytime going straight to the ground.

I shall try it and videotape it so you can give me your advices on that flying attitude.

I updated this thread since i said i would do it whatever the result. Still need your inputs.

Cheers and thanks.

Guy

 

[BridgeInspector]

Does it glide with no power? If so it may need thrust angle changed on motor.

 

[Guy]

Hi Bridge inspector, thank you for your suggestion.

I did a 2/3° down angle on the motor.

I am pretty sur this problem is due to a bad CG or lack of power.

I ll try to videotape the repairing and flight test so i can have your advices on my wrong doings.

Cheers. Guy

 

[Christopher14]

On my 560mm FT Spitfire I have roughly 2 degrees thrust angle to the right and no down at all. I would recommend right thrust. And is the plane nose-diving or banking into the ground? It took me a day of testing and correcting to get the 560mm Spit flying well.

My setup is as follows:

prop: TGS Sport 4.75x4.75
motor: Turnigy SK3 2118 17gram 3100kv
ESC: Turnigy Multistar 10amp 2-3 cell
battery: Turnigy 500mAh 2s 20-30C
servo: Turnigy 1370 3.7gram

 

[Guy]

Allright Christopher, thank you for your help

I'll try the 2° right angle for next time and no down. Plane is nose diving, but again, i think the best is to fix my gopro on my head and try to get this on tape ;-)

Thank you.

On my 560mm FT Spitfire I have roughly 2 degrees thrust angle to the right and no down at all. I would recommend right thrust. And is the plane nose-diving or banking into the ground? It took me a day of testing and correcting to get the 560mm Spit flying well.

My setup is as follows:

prop: TGS Sport 4.75x4.75
motor: Turnigy SK3 2118 17gram 3100kv
ESC: Turnigy Multistar 10amp 2-3 cell
battery: Turnigy 500mAh 2s 20-30C
servo: Turnigy 1370 3.7gram

 

[nerdnic]

Hey Guy, got your PM and I'd be glad to help.

1. That motor is more than enough power.
2. What is your AUW?
3. Where is your CG?
4. If you take the prop off and throw the plane at a 45 degree angle into the air what happens?
5. When you crashed did the plane roll to the left or just nose dive straight down?

Let me know the answers to these questions and include a video if you can.

 

[Guy]

Hello nerdnic
Hello every one

Thank your for kicking in ;-)

I just did a video i am currently uploading for you guys - i'll post the link here when the file will be fully processed.

I tried to address all your askings this morning but there might be wrong doings so i did prefer a friendly mini video to show you what is going on.

I have one question though:

What is AUW stand for ? Is that All include weight ? I guess so

I weight the whole setup at 205 gr (14 pb gr included)

I ll post the video link in few min hopefully.

Best&Bless

Guy

Hey Guy, got your PM and I'd be glad to help.

1. That motor is more than enough power.
2. What is your AUW?
3. Where is your CG?
4. If you take the prop off and throw the plane at a 45 degree angle into the air what happens?
5. When you crashed did the plane roll to the left or just nose dive straight down?

Let me know the answers to these questions and include a video if you can.