Viewing 15 posts - 1 through 15 (of 19 total)
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  • #40007
    Kevin_Erik
    Moderator

    Is this possible with the mini’s built in FC to use a 6S LiPo?

    Note: The ESC’s will support 6S and the motors would require swapping out as the RS2205’s are limited to 4S.

    I did a little E-Calc tweeking over the last few days. Now assuming it’s possible to use a mini with a 6S LiPo…

    Swapping out the current ESC’s and motors for the Aikon 35A ESC / F80-1900kv and assuming 1500mah LiPo @ 65c / 130c burst is used. The max speed would be well over 160kph, using the stock 6×4.5×2 propellers. This would also allow flight times in excess of 12-15 minutes. (roughly double the current)

    Here is the OLD copy of E-calc, with lots of mistakes (6×4.5×2 Props, 6S LiPo, F80-1900KV Motor)
    ecalc @ 6S

    Updated (12/22/2017) E-Calc #1 (5×4.5×3 Props, 6S LiPo, F80-1900KV Motor)

    Updated (12/22/2017) E-Calc #2 (6×4.5×2 Props, 6S LiPo, F80-1900KV Motor)

    #40129
    Kevin_Erik
    Moderator

    Come on… not a single reply?

    #40132
    biggestRCEfan
    Participant

    Interesting idea. I found going from 3S to 4S gave me enough step-up in terms of responsiveness and speed. Since then I progressed flying FPV so maybe 6S would be interesting if you want to race.

    Did you check if the targeted 6S will fit?

    #40137
    Kevin_Erik
    Moderator

    My only real concern is the tail servo as its voltage is stepped down via the BEC. With 4S this isnt an issue but 5-6S this could cause the BEC to overheat. Looking to see if someone has tried this so i dont have to risk everything just to find out. Its also possible to use a stand-alone BEC to control the voltage independently of other systems and thus only for use by the servo.

    Battery comparison
    Turnigy Nano, 4S 1800 mah 103x35x29mm, 204 grams, 35-70C
    Turnigy Nano, 6S 1550 mah 120x34x27mm, 247 grams, 65-130C

    The lenght of the battery would require reworking of the canopy and the addition of a slightly longer tail boom. However it could also be underslung along the centerline of the frame.

    With the 4S LiPo, F80-1900kv motors and Master Air Screw propellers i can get about 12 minutes of hover or 8 minutes of freestyle flight. (Flight weight of 640 grams) This is in contrast with the stock Tri-mini that gets 8-9 minutes hover or 5-6 minutes of freestyle flight. Now with an 6S, F80-1900kv motors and 6×4.5×2 propellers the max hover can go 14.9 minutes as per ecalc. However in my experiance, E-cals estimations are a bit conservative so I’m expecting closer to 16 minutes. This would almost double the stock flight times. From what I can tell, the larger celled LiPo’s are more efficent per gram of weight so seeing if the Tri-mini can use one would really open up new capabilities for it. (motors are voltage driven so this makes sense)

    Also note that the Ecal was done using the 6×4.5×2 propeller instead of a 3 bladed prop. However again I expect a three bladed prop to do better performance wise but the 2 bladed prop would have the best flight lenght. The Ecal estimate also stated a top speed of 160 kph but i also feel that this is pretty conservitve considering the experiance I have with ecal vs the modifications i have made to my own tri. (thats when i dont step on it and break arms and solder pads)

    #40304
    Kevin_Erik
    Moderator

    Just installed Master-Air-Screw 7x4x3 (3-Blade Series)… still running the 4S as I dont feel safe exposing the BEC to that level of input voltage.

    #40406
    LitterBug
    Participant

    I am actually pondering a 6S conversion on mine. I have a DTFc FC/PDB on my Mini Tri that is 6S capable. I just need to double check my servo BEC. Have plenty of 6s capable ESCs, and some motors as well. Doing it more out of a efficiency/ long flight time aspect than all out speed.

    Cheers!
    LitterBug

    #40435
    Kevin_Erik
    Moderator

    Try 5S first and step UP from there. Better to have a little overheating than the whole thing on fire.

    Question how are you using a 3rd party FC on your Tri. I’ve looked everywhere and have seen next to nothing about how to connect the servo, map it and tune it. I’m interested on building a Baby Tri using a Maytek FC / PBC AOI.

    #40450
    LitterBug
    Participant

    No worries with 6S if all the gear is rated. I will be using a smokestopper on initial powerup to be safe…. Ordered a set of F80 1900kv motors. They should be more than up to the task.

    I’ve documented my build thread here: https://rcexplorer.se/forums/topic/rcexplorer-mini-tricopter-build-thread/ Basically comes down to ordering a non-FC kit (ie with G10 top board rather than the F3FC top board, and drilled FC mounting holes. I later ordered a second carbon bottom board and may drill FC holes to replace the G10 board.

    Cheers!
    LitterBug

    MiniTricopter kit

    #40452
    Kevin_Erik
    Moderator

    I’ve ordered a Baby-tri today and will make this my platform for 5″ Duct experamentation. Currently have three Emax LS2207-2550KV motors that I’ll use for the Baby build. This will start off as F4FC, just need to get off my butt and choose the FC make and order it.

    Once this is done I’ll convert the Mini-Tri to an F4FC running F80-1900KV motors @ 6S. (already have F80’s installed) Currently running Master Air Screw 6x4x3RS as they give the best three bladed thrust I’ve found thus far.

    #40456
    MadPoet
    Participant

    Hey Erik (or do you prefer Kevin?),

    Is this you: https://www.thingiverse.com/thing:2556626

    I’ve been planing on printing those up to give them a try. If that’s not you, can you post a link to your ducts so I can give them a whirl on my Baby Tri?

    Cheers,
    ~Eric

    #40458
    Kevin_Erik
    Moderator

    Yeah that my project in all its glory.

    As for the Naming… I made an account for both me (Kevin) and my son (Erik) as the Tricopter was a joint project. Keep in mind though that he’s six and not skilled enought to fly anything yet. We do fly together with Erik wearing the FPV-glasses to spectate.

    About your Baby-Tri, I don’t have one yet (it’s on order) so I’ve yet to be able to fit check the ducts with the Baby frame to ensure that you’ll have the clearance needed. This is especially important for the tail servo as you don’t want the tail smacking the frame during hard turns ect. I’d strongly suggest you make a cheap / quick print to perform a test-fit. This will allow you to figure out what if anything needs to be adjusted. Should you need a few tweeks to the model, i could model the changes if your able to provide the exact dimensions needed. Also be aware that the Duct is sized for the 2205 motor stator. Motors larger than this may work but could cause rubbing issues against the motor case or servo block. Only way to know for sure is to try it and see.

    Its also possible that to have the proper clearance, the Baby-Tri would require the use of inverted motors / props (front only). The tail remains in its standard position, with the battery slung under the Tri’s belly, between the front ducts.

    Shims are important! They’ll allow you to center the propeller precisely within the duct. Afterwards then tighten down the motor mounts in a cross pattern and remove the shims. I’d suggest using some form of packing cardboard that’s both stiff and smooth. Rather like the nice packaging that most of our motors comes in. The cardboard needs to be .05 mm in thickness so it can slide between the prop and the duct-wall.

    #40490
    Kevin_Erik
    Moderator

    I’ve updated the E-Calc’s on the first page as I found several mistakes. The changes are pretty f’n good and would look like a really wild ride for anyone brave enough to give it a try. Odds are this could be one of the fastest Tri-Copters currently flying.

    Kevin

    #40495
    LitterBug
    Participant

    Yeah, so this is really happening! 🙂 F80 1900kv arrived today. Thanks Santa!

    Cheers!
    LB

    #40496
    Kevin_Erik
    Moderator

    Pics or it didnt happen.

    : )

    Consider using a heatsink on the BEC, there are several small ones made for chips. Most simply attach via a conductive adhesive. Just a quick example: https://www.amazon.com/Aluminum-Chips-Cooling-Heatsinks-cooler/dp/B00E36SEB4

    #40500
    LitterBug
    Participant

    True dat…
    PowerUP

    Hasn’t happened, but it will soon….

    Along with KK6045 2blade props, this thing should be a ripper! (tested those on my 6″ quad)

    No need for heat sinks. The DYS have heat spreaders, but again, on 6S there will be lower current and less heat.

    Cheers!
    LB

Viewing 15 posts - 1 through 15 (of 19 total)
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