Wattflyer RC Network: RC Universe :: RCU Magazine :: RCU Forums :: RCU Classifieds :: RCU User Reviews :: RCU YouTube
Home Who's Online Calendar Today's Posts RealTime Post Spy Mark Forums Read
Go Back   WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > Electric Ducted Fan Jets
Register Members List Wattflyer Extras Articles Search Today's Posts Mark Forums Read Social Groups

Electric Ducted Fan Jets Discuss electric ducted fan jets here including setup tips, power systems, flying techniques, etc.

Thank you for your support (hide ads)
Reply
 
Thread Tools Display Modes
Old 06-23-2012, 07:40 PM   #1
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default Help with the T45 64mm power set-up pls

I've built the Hobby King T45 64mm EDF .... the $29.99 kit job ... which is the Lanyu model - known to fly well.... Youtube has many on there.

My DF unit is the stock 64mm unit.
Motor is the 2610 5000kv Turnigy EDF motor
ESC is Hobbywing 40A Pentium, needs higher rated ...
Model ready to go without battery 484 grams
With 3S 1800 LiPo AUW 618 grams
3S 1300 LiPo AUW 597 grams
4S 1500 LiPo AUW 630 grams

Factory recc'd is :
2810 4300kv EDF motor
30A ESC
3S 1300 20C Lipo giving AUW of 560grams ..... (I have never seen a model meet factory weight yet ! )

Test figures ............. using Trakker Wattmeter and Digital balance.

3S 1800 25C = 38 amps, 380 watt, 450 to 460 gram thrust ( 0.74 : 1 )
Theoretical run time max of 2,8 minutes at WOT

4S 1500 25C = 52 amps, 680 watt, 500 to 510 gram thrust ( 0.8 : 1 )
Theoretical run time max of 1.7 minutes at WOT

With these packs - she balances near spot on CoG marks. The 12 gram weight difference making only a change that can be accepted as a safe margin.

I'm jusing compact LiPo's now to get max capacity per weight / size but as you can see the run time is too short. Al;so the LiPo's are running at extreme and I expect to puff a few at that rate of demand. Higher C rating increases weight dramatically adding to the problem.
The ESC will need periods of slow running to cool of .... I shall change it for a 50A - max physical size you could squeeze into the special tunnel for it - unit later when I receive my next boxfull of goodies in post.

What to do ? How to cure this without weight addition at rear end to balance out bigger battery ?

Mid battery point back to CoG is 18cms, from CoG to suitable flat area at tail to add weight is 39cms. Any extra weight x at battery means correction of x * 18 / 39. Example increasing LiPo to a 3S 2100 of about 200 grams means an extra weight of about 55gr at front, needing 25gr at tail.
Thrust to weight ratio now being 455 / 684 = 0.67 : 1 on a 3S .... if I can get a light 4S ...

Ideas guys ?

Nigel

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Old 06-23-2012, 10:28 PM   #2
pmullen503
Member
 
Join Date: Mar 2011
Posts: 801
Thanked 64 Times in 63 Posts
Awards Showcase

Scratchbuilders Award 
iTrader: (0)
Friends: (3)
Default

Doesn't seem to get much more thrust going to 4s. 3s looks like the more efficient choice.

Have you flown this yet? How much actual flying time do you get with 3s 1800? The 1800 pack may be adequate. How sensitive is it to CG? I assume there is no room to move the battery back a bit to accommodate a larger battery. Maybe the larger pack will need less tail weight than you think.

If you haven't flown yet, I'd try it out with the 1800 pack for even a short flight.

It's never too late to have a happy childhood.
pmullen503 is offline  
  Reply With Quote
Old 06-24-2012, 08:41 AM   #3
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default

Originally Posted by pmullen503 View Post
Doesn't seem to get much more thrust going to 4s. 3s looks like the more efficient choice.
I agree that the weight penalty may be greater than the thrust increase, but the 4S puts it at the 0.8 ~ thrust to weight ratio.

Have you flown this yet? How much actual flying time do you get with 3s 1800? The 1800 pack may be adequate.
I am surprised at the lack of run time considering I'm close to factory except on the higher kv motor, but that's only 4300 up to 5000kv ... Youtube shows it flying on 3S .... I usually fly to 3mins or so - so maybe it will be enough ... but would like a bit more margin and not driving LiPo to near zero !

How sensitive is it to CG?
If like my other T45 ... they are quite tolerant of CoG so the battery range should be possible.

I assume there is no room to move the battery back a bit to accommodate a larger battery. Maybe the larger pack will need less tail weight than you think.
I am looking at 3S 2200 higher C rate along with a heavier ESC. The ESC can be slid back a few cms to help balance out. Then maybe 10gr or so at tail .... but even with the 2200 - I'm still only looking at theoretical 4.3 mins.

If you haven't flown yet, I'd try it out with the 1800 pack for even a short flight.
That's my intention ... see how she is with the 3S 1800 .... if she flies well on 3S ... then I will go for higher capacity packs, I have some from my 450 Heli that I don't use ... but will need to sort balance out.

Cheers
Nigel

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Old 06-24-2012, 06:55 PM   #4
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default

Now fitted the 70A ESC but it's a real tight fit in that tunnel. It also pressed hard on the elevator cable tubes trapping the cables. I had to move it slightly forward so tubes were not pressed so hard.

Balance with a 2100 3S is not too bad .. let's call it SAFE ! She may need a bit more throttle on landing to keep nose up.

Nigel

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Old 06-29-2012, 08:37 AM   #5
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default

Well I bit the bullet and ordered a 4300kv 2810 motor to swap out the 5000kv .... that way I hope to get amps down and extend run-time.

I have 4S 1600 35C compact packs coming as well - so should be well powered.

The ESC will be swapped out as well back to a 50A smaller job easing the pressure on those elevator tubes.

Once she's flown and sorted out to a sweet baby - the wheels and U/C stuff will be removed .... lighten her up by about 50gr, about 30 of which is nose wheel and servo ... and that will help the CoG and power weight ratio.
A small hook under to use my catapult and bingo.

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Old 07-02-2012, 12:39 PM   #6
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default

As a follow on from my previous asking for help in getting the Lanyu T45 sorted for larger LiPo and better run-time ... the possibility of re-locating elevator servo from front compartment to rear ..
The fuselage has a tunnel for ESC above the ducting. The elevator control cables run there also.
I wonder about shortening cables, set the servo in tunnel behind EDF. That transfers 9gr from front to rear, a total iof 18gr change, with a double benefit that the location aft is 2x the distance from CoG ... so effectively 18gr added to tail and 9gr removed from front.
It may be an idea to have elevator servo split to 2 ?
The removal of the servo may allow the Rx to be set where the servo came from, the battery area enlarged .... giving me the increase desired .... a 4S 2100 ....
This comes from noting the SAPAC version has the elevator servo at rear ... and a larger battery area. The models are similar size and both foam ... with 64mm EDF's. But the SAPAC is rec'd for much larger LiPo ..
Nigel

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Old 07-07-2012, 04:16 AM   #7
solentlife
Super Contributor
 
solentlife's Avatar
 
Join Date: Oct 2010
Location: Ex UK Brit now in Latvia west coast - Ventspils
Posts: 5,921
View solentlife's Gallery47
Thanked 235 Times in 232 Posts
Club: Founder Member Ventspils RC Club. Ex Waltham Chase and Meon Valley Soaring.
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Outstanding Contributor Award  125mph Speed Demon 
iTrader: (0)
Friends: (15)
Default

4 ultra mini 4.3gr servos on order now ..... reckon I could squeeze a couple in at back end.

Will upload photos etc. when i make the modifications ... show result.

Nigel

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
- Subscribe my Youtube: "solentlifeuk"
solentlife is offline  
  Reply With Quote
Reply

  WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > Electric Ducted Fan Jets

« Previous Thread | Next Thread »

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Everything You Wanted To Know About Electric Powered Flight AEAJR General Electric Discussions 269 06-27-2014 01:06 PM
Everything You Wanted To Know About Electric Powered Flight AEAJR Beginners 149 06-07-2014 03:57 AM
Lanyu 64mm T45 / Hawk ? solentlife Electric Ducted Fan Jets 4 06-17-2012 05:01 PM
twin prop power set up smooth operator Power Systems 26 08-04-2011 03:43 AM
Deltrum 70 MM DEF power combo set Ray_ja Hi-Performance and Sailplanes 0 07-05-2011 03:35 PM


All times are GMT +1. The time now is 12:39 PM.


Powered by: vBulletin
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 WattfFlyer.com
RCU Eflight HQ

Charities we support Select: Yorkie Rescue  ::  Crohn's & Colitis Foundation



Page generated in 0.17151 seconds with 31 queries