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TOPIC: Wannabeaflyers Eppg Dream

Wannabeaflyers Eppg Dream 3 weeks 1 day ago #1153

Hi e-Hg,
I'm sorry about your lost :-(
70-80 degrees is ok I think more I would not allow for the motor. Yesterday I finished my thrust measuring bench now I'm waiting for my propeller spacer and slowly ready for real tests.

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Wannabeaflyers Eppg Dream 3 weeks 1 day ago #1154

Hi, 18s and 130 amp Is more than 8kW power I think there is a lot of thrust. I don't know how much you weigth but for me (75kg) 35-40 kg thrust is enough. With 8 kW if you have a good propeller there is more thrust in my opinion. With e-prop (or Helix) you can't go better I think.
Back to the frame question: attached some pictrues about the cage I use now for my petrol paramotor. The same I use for the e-ppg. On the e-ppg there are a lot of steel parts yet. If the bench test are ok and I see it is worth to spend a lot of time in my workshop :-) I will make all parts from carbon fiber, titanium bolts ect just to have the lightest frame possible.
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Wannabeaflyers Eppg Dream 3 weeks 1 day ago #1155

I'm not planning to use any fuses. If the maximum amp is measured on the bench there is a need to have safety margins in the system. For example if you let 130 amp you need to know your system would hold up 160-180 at least. For normal use there is no need of fuse in my opinion. If anything is going wrong, short circuit or se than somewhere the cable or soldering will melt anyway acting like a fuse.
If I understand it right today is fligthday there. Safe landings :-)
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Wannabeaflyers Eppg Dream 3 weeks 1 day ago #1156

Hi Roland Thanks for posting the pics , Yes That's the one I saw , loved the simplicity of the design and may well try to do something along the lines of your design .

I Weigh 95KG so for me if the thrust is good then that's a major plus .. once again thanks for the tech info its very much appreciated and im soaking it up like a sponge .

my test times are still too short to give decent tech feedback but as with most things once I sort out the fuse Scenario I can move on to longer test runs .. loved the Fan you added to the C120XX Motor , nice clean and falls withing my DIY skill set But I may need to modify the concept to work with my E-one setup any system to draw cooler air over the windings cant be a bad thing , so gotta say thanks for showing me a possibility ..

Had a great days free Flying with 3 Nice top landings so no majork uphill walking ( mega Bonus for me LOL )

Same ol same ol i'll post more info with the next round of testing .. and will let you guys know about the Fuse Option if it will be removed etc . Good advice and i'll take that on board as we say in the UK :-)

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Wannabeaflyers Eppg Dream 2 weeks 5 days ago #1158

Just for information , I think I may have found the reason my MCB fuse tripped during testing , just been checking the specs and it appears I have was either a 24 or 48 V 200Amp rated unit and seeing as I'm now pushing a full 75Volts initially , I'm thinking this may be the issue ... either way im currently fitting a standard cartridge 160Amp fuse and also have 200 Amps as alternates ...

I intend to use these while ground testing and see how the system performs . They may or may not be included in the flight version setup
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Wannabeaflyers Eppg Dream 1 day 5 hours ago #1159

OK he's back another wee update , been off due to eye operation but back in business now hopefully , OK today did some more spin up test this time increasing the duration but varying the throttle load to simulat take off and cruise , Basicall running my fully charged 18S packs 75Vdc fully charged at 20Amos out ( 10c battery rated )

so the test was for 5 mins duration and some figures ( reaaly must get datalogger of some sort ) .
test start =75VDc Full throttle = 130- 138Amps Peaks)
50 seconds into test battery Voltage = circa 69.8 vdc current = 85amps
60 seconds battery voltage = 68.7 Vdc @ 110Amps throttle maxed out still
105 seconds " " " " = 71 Vdc @ 100 Amps Throttle set just under 80%
160 seconds " " " " = 67.6 Vdc @ 100 Amps Throttle set just under 60%

test stopped as voltage was getting to safe cut off point......

Noted after stopping test battery voltage recovered to 71.5VDc Cell checker on 1 6S pack showed 23.3 Vdc so packed seemed to indicate still had some charge left (50% ) so this was my dilemma ..

Anyways continued the testing as the cell checker indicated some more capacity could be used ..

the upshot of this round of testing showed large sag initially ( to be expected ) and that by running at full throttle but reducing it once climb attained should see longer pack duration ( closer to 20 Minutes flight time ) But don't quote me on that im a newbie remember ..

the next tests will be Continuous running for 8 Minutes ( 1st 2 @ max throttle , Then reduce to Cruise for next 6 mins with Full throttle blips in between ) . just to see where the pack voltage ends up after the run ...

Still not very scientific as I spend a lot of time watching the E-one unit for vibration and trying to get a feel for how the motor is running , I have made videos of the instruments as a second pair of eyes but really this needs data logging to take the manual rounding up of data times /Current / Rpm etc to minimum

Also noted the RPM at Full speed with fully charged pack being circa 5080 RPM as seen by Rev counter so at 2:1 reduction ratio that puts me in the ball park for correct prop speed < 2500 ish RPM

All my Connection leads from battery to motor to ESC seemed below Ambient and non more than 20 degrees C after test run .
Motor bell ( Rotor ) temperature indicated as <60 Deg C
Stator windings measured as < 65Deg c after test ( expected higher But Lower is good ..
Rotor was Hot to hand touch test but again this was to be expected . after 5 Min combined Run test time ...

Hope ther was something in this update that can help , still need to do better / Longer duration ground test but need to change timing as I think I noticed the same issue Bo came across and really statrt to stress the whole package a bit more ( scary stuff Wallet wise LOL ) New E- PROP Coming soon so that should up the anti Thrust wise ..

Forgot to mention according to my rig im only seeing just over 35- 38 Kg thrust , so really hoping the new prop will tip me towards the >45Kg Take off Thrust target.
Cheers Guys
.

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Wannabeaflyers Eppg Dream 1 day 4 hours ago #1160

another Wanabe Update I forgot to add , I have designed and 3D printed a hand held throttle unit which uses standard E-bay £4.00 servo tester without needing to solder leads and remove the existing Pot , set attached pictures , just printing the top cover plate and waiting for spring and it should be good to go ..

A) Basically the idea was to but inexpensive Servo tester ,
B) Remove the Plastic Sleeve and fit a 3D printed Pinion ( press Fit or Glued ) to the Pot as supplied .
C) Clip servo tester into 3D printed handle along with 2 Servo extension leads ( male / Female )
D) Insert Throttle lever Rack
E) Attach Extension Spring
F) check for full Pot travel when Lever is pressed ( adjust position if required )
G) fit base + Top Cover plates
Connect 1 lead to BEC and the Other to ESC
Job done ( LOL )

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Wannabeaflyers Eppg Dream 9 hours 12 minutes ago #1161

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Hey Wanna - clever design with that throttle and interesting testing results :)

FWIW I agree with Roland, fuses can be left out, especially if you build in a weak-point. I remember fuses came up on RCGroups once, the general consensus was the connection tabs on the lipos go open-circuit if things go zap. We have a lot of lipos in parallel so not sure if this still applies? For me, I made a shorting link using a smaller gauge wire (8 AWG) than the rest of the chassis wiring (3 x 10AWG in parallel). This link is also my safety switch as when removed it breaks the series connection between my two battery banks. I used AS150 connectors which takes care of the connecting spark (ESC capacitors) as well :)

Fun fact: In one of Richard Browning's interviews (the real-life Ironman) he said the team ended up using a hammer-drill trigger for the controller trigger. Pretty smart thinking I reckon, if you've ever used a hammer drill you'll appreciate the crap that the trigger gets!

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Sorry not PG, but electrons are electrons right!