Hi,

Do anyone on this forum have experience with IMAC sequence flying with electric motors and planes of 35% or bigger?

Surely find alot of threads on rcgroups etc on electrified IMAC machines but fail to find that many has real experience with this for sequence flying.

Especially for Intermediate and above I would be very interested to know about experiences on motors used, planes and battery setup.

best regards
Ketil

I don't know of anyone flying large electric IMAC planes in competition.

It is a little different than pattern in the sense that, pattern you fly one sequence and land. 8 min from wheels up to wheels down.

IMAC you must have enough power to fly two full sequences without landing.

I know Jason Noll set up his Bipe to do just that but he told me he could only get one good seq. then he needed to land and change batts. But for one seq. he had unreal power and it was supper quiet. Maybe you can get him to jump in here and tell you what he was using.

It most definitely can be done. On a 35% airplane a Hacker A100 on a 27" or 28" prop would would well with a 12s 15,000-20,000mah setup. I know there was a foreign competitor several years ago who flew a Plettenburg motor on a 14s or 15s setup in the unlimited or invitational class out at the TAS event.

The big issue I see with flying big electrics especially in IMAC is the need to have lots of batteries and then the means to be able to charge them all. I'm a huge fan of electrics and love to fly them but as denoted above getting a some what affordable setup that can fly a round (2 sequences) in IMAC is very challenging............but doable if you have the $$$$.

Tim

Have a friend over here that flyes a 36% 3W Votec with a Plettenberg 30/8. Uses 10 Ah at 15S.

He has more power than anyone with gassers ... He gets two sequences Sportsman within 65% discharge. His setup seems to be well dimmensioned both for Intermediate and Advanced.

If you can go a little smaller on the plane, I have an EF 70" Extra that flies 9-10 min on an 8S setup making 2000W. I'm pretty sure you could take their 78" and easily get those times on a 10S setup. Except when it gets windy both those planes can easily fly Basic and Sportsman sequences twice with sufficient power at the end.
I personally like the idea of electric.

Terry

Posted By Terry on 03 Oct 2010 18:20

I personally like the idea of electric.

Terry

Agreed!!

Tim

Posted By Ketil Aagesen on 03 Oct 2010 15:59

Have a friend over here that flyes a 36% 3W Votec with a Plettenberg 30/8. Uses 10 Ah at 15S.

He has more power than anyone with gassers ... He gets two sequences Sportsman within 65% discharge. His setup seems to be well dimmensioned both for Intermediate and Advanced.

Ketil,

Who is this. If it is someone in the NE region, I have never met him and I pretty much have met everyone that normally flies in our region, which very few exceptions

I believe he is in Europe.....

Thanks Curtis, I noticed he listed NE for his region and I have yet to run into anyone that is using electric for Sportsman and above

Yep... I wish we could....but I think the limiting factor is still the flight time.........

Soon I hope...Soon!

Posted By Bill James on 04 Oct 2010 17:03

Posted By Ketil Aagesen on 03 Oct 2010 15:59

Have a friend over here that flyes a 36% 3W Votec with a Plettenberg 30/8. Uses 10 Ah at 15S.

He has more power than anyone with gassers ... He gets two sequences Sportsman within 65% discharge. His setup seems to be well dimmensioned both for Intermediate and Advanced.

Ketil,

Who is this. If it is someone in the NE region, I have never met him and I pretty much have met everyone that normally flies in our region, which very few exceptions

Hi,

See that my region is noted as NE. Do not know why but I am from Norway in Europe. Most of us that fly IMAC over here are also US IMAC members.

So, this guy is also Norwegian.

We've got a few people in Canada running electrics in Sportsman. Goeff Dryer out in BC is flying a 35% H9 Extra on a Hacker A100 (http://www.rcgroups.com/forums/showthread.php?t=1157267). Phil Stang is local here in Ottawa and was flying an 88" Extreme Flight Extra as an electric. I haven't flown much this year (traveling) but did fly one contest with an Extreme Flight 78" Extra (electric) in Sportsman. I have a 35% H9 Extra as an electric that is nearing readiness for a maiden flight, I will be flying it next year in Sportsman. I'm going to start with 14S/10Ah using a Plettenberg Predator 30/8. There's no reason in Sportsman that you couldn't use a smaller airplane, I didn't feel the least bit at a disadvantage flying my Extreme Flight 78", what problems I had were all my fault and nothing to do with having a smaller plane. My guess is that the numbers of electrics in IMAC are going to double every year and slowly but surely you will start seeing them in higher classes once the bugs are worked out and it's proven that they can be competitive.

Just thought I'd append to this. I've now got 7 flights on my H9 35% Extra using 14S/10Ah (14S 5Ah x 2P) and the Plettenberg Predator 30-8, Jeti Spin 200. AUW with the 28x14 is 30lb6oz. It's somewhat less with the Mejzlik 26x15 thin electric prop installed. Smaller batteries could be used as well which could shave off maybe 8oz. I like having extra capacity in reserve in case I need to fly some circuits or take extra trim passes.

I've flown it with an Engel 28x14 and then tried a Mejzlik 26x15. The 26x15 is more efficient and flight speeds are faster (would probably be good on an insane windy day) however I hated the downlines, not enough braking and the plane would accelerate all the way down. Also the prop will get noisy at anything over 1/3 to 1/2 power with the 26x15. On the Engel 28x14 it's less efficient (always a concern with electric) but the downlines are very nicely controlled so you can maintain approximately same speeds up and down and not be accelerating on the way down which makes centering everything and keeping constant roll rates that much easier. So I switched back to the 28x14. In either case, I can fly two 2011 Sportsman sequences using less than half the pack; again the 26x15 is maybe 20% to 25% more efficient. You never need to use more than maybe 2/3 throttle in the Sportsman sequence.

Ray Buyugurel and Isabel Deslauriers came by our club last weekend to try it out, Ray flew Unlimited last season and Isabel will also be joining him in Unlimited next season; both are amazing pilots and maybe if I work on it really hard for the next 10 years I might someday be fortunate enough to lose to them in the same class as them. Anyway, Ray felt the plane would be competitive up through Unlimited, his comment was that it had more power than any 35% he's flown.

Posted By eajohnson on 09 Nov 2010 13:21

Ray Buyugurel and Isabel Deslauriers came by our club last weekend to try it out, Ray flew Unlimited last season and Isabel will also be joining him in Unlimited next season; both are amazing pilots and maybe if I work on it really hard for the next 10 years I might someday be fortunate enough to lose to them in the same class as them. Anyway, Ray felt the plane would be competitive up through Unlimited, his comment was that it had more power than any 35% he's flown.

That they are. I've flown with them before and against Isabel one time. The first time I saw her fly I told the others we were going to get our butts whooped and she did exactly that.

She used to be an ARD for me and once I read her bio, it's easy to see why she is so good. All she has ever really done is heli and IMAC.

It was always cool to see them get to 35% planes, all their camping gear, themselves and all the items needed for the planes into that little car. I seem to remember they are both using the Carden now.

same here, electrics rock!!!!!

My AJ Slick is set up for IMAC, but I can only fly one sequence at a time.

I know this is a bit petty but I really enjoy the sound of a 150 on greeves and
other gas setups. Electrics, for all of they're pluses, slill sound unlike a full scale
aerobatic plane. I guess if I'm for pilot and panel, I'm for scale sound too.
See, I told you it was petty.....

Hey Randy, you can always make motor sounds while your flying electric just so you get that scale feel. You know your just a big kid at heart. lol

Actually, I tried clothes pins and playing cards but it just wasn't the same...
On the upside, if we all went electric, sound scores would
mean nothing and have zero impact!!

Posted By Howard Pilcher on 09 Nov 2010 21:22
My AJ Slick is set up for IMAC, but I can only fly one sequence at a time.

And seriously Howard, do we know anyone who can fly
two sequences at the same time???? No Way man!!!

At the Mocksville fall contest, there was a young man flying a 50cc class airframe electric in Basic and he could fly both sequences... really had to manage the throttle to get through though.

Posted By Curtis Cozier on 12 Nov 2010 12:55
At the Mocksville fall contest, there was a young man flying a 50cc class airframe electric in Basic and he could fly both sequences... really had to manage the throttle to get through though.

Flying the basic sequence on an electric powered 50CC setup is very managable. I flew a 50CC setup on a 12s 5000mah and a 12s 5350mah setup and had no problems getting through a round of basic. The only time things got a little iffy was when the temps. in the morning rounds got a little cold in the early May contests.

Tim

The sound of a gas engine........aaaaaaaaaaah........

Posted By Randy Wegner on 15 Nov 2010 19:26
The sound of a gas engine........aaaaaaaaaaah........

That's why I set up my chair right next to my generator.

Although I prefer the "scale" sound over electric,
flying gas and glow for thirty years is probably why my
ears ring a bit now.

I like the sound of gas too... I'm all for Sound scores with gas engines, the louder the higher the score!

Posted By WMinear on 28 Nov 2010 13:55
I like the sound of gas too...

Me too... but my wife complains.....

Posted By Curtis Cozier on 29 Nov 2010 15:20

Posted By WMinear on 28 Nov 2010 13:55
I like the sound of gas too...

Me too... but my wife complains.....

She's not the only one complaining about your gas.

ouch!

Hi,

Will use 10Ah 15S setup on my Votec 36%. Plettenberg 30-8. Jeti Spin 220. Tuned down to max voltage similar to approx 14S. According to tests with my friends similar setup this will give approx 11 kW with Mejzlik 26x15E. Two sequences within 60-70% battery capacity.

Will be used for Intermediate and Advanced.

Picture of motorsetup and plane attached.

Ok,

Finished plane. Flying weight slightly less than my gas setup (had a 3W112 4Cyl in it before).

Pit tested the e-motor with 26x15E. 7100 rpm shown on Jeti box, approx 7040 rpm on handheld tachometer......Will at lest adjust down to 6500 rpm for normal sequence flying.

This stuff has serious power..Seems to be much more than the 100-120 cc class gas motors. Are looking forward to flight test soon.

best regards

Hi Ketil.... That is some good news. Please keep us informed of your progress & flight tests.

I have discussed with our new Rules Committee Chairman, Pete Castine, the possibility of allowing ONLY electric engined models the option of landing in between sequences to change batteries, because of the "nature of the beast".

If this is acted upon, it would not become a rule before 2013...but it is being seriously considered.

Best regards, & safe flying.
Wayne

Could we get you to tell us about your battery set up along with some pictures?

Hi Wayne,

That is a very good idea. Such an incetive would be very helpful to get more electric powered IMAC models around.

Gil; attached a picture of my 15S2P setup mounted on a plate for easy insertion through cockpit. Are using 6 pcs 5S 5000 mAh packs to form one flight unit. Total capacity then 10 Ah I am throught the regulator tuning down max voltage from regulator to motor to approx 80%. This as I do not need the top rpm max voltage would give but I need the extra flighttime, and I am using standard F3A 5S packs.

Best regards


Ps...For some odd reason I cannot get in more pictures..will try again

Update;

I have now 5 very good days flying with my 36% Votec 322 el-conversion.

Power is just so much more compared to any 110-120 ccm. No torque changes in verticals makes all climbes so much easier. I had to de-rate and lower the power outake to get easier control over vertical manouvers. Unless the vertical acceleration is too great. Low level 3D without the worry of engine cut...

There is ofcource some work that has to be done between each flight (change of batteries / pit charging), but all in all the advantages in the air are so tremendous compared to gas engine operation. And the sound score...

I will use this one for my competitions this year to get more experience. Intermediate first and later this year Advanced.

Wayne's suggested rule change is very interesting and I am sure this will make more people interested in and aware of the advantages of electric IMAC machines. Many IMAC pilots has 48inch or so electric Extra's etc for afternoon fun flying. Just imagine the similar performance, sound and easy operation of an electric 35-40%...

best regards
Ketil

Posted By Ketil Aagesen on 25 Apr 2011 17:12

And the sound score...

best regards
Ketil

I don't know that there is much of an advantage there for the sound score. Many still think it is based on throttle management and my son has receives scores anywhere from 6 to 10. Most around 8.

Straight from the rule book:

Judges will evaluate each individual sequence flown in its entirety for overall sound presentation.

Even though the electric is quieter than the gas until more people read the rule I don't think it is an advantage.

BTW, he flies a 50cc plane in basic and has no issues flying his routine with 12s 5000mAh packs.

Mike

Hi,

Yes. Throttle management and propeller dimmension is important. However if you cannot get 10's with an electric drive you cannot get 10's at all... Not too much to gain by 10's in sound score today but who knows in the future.

Ketil

Hey Ketil,

Interesting stuff. Does your jeti controller have a braking function?

Just back from the Nordic IMAC Championship 2011. I can confirm, Ketil's machine have
both the performance and duration needed to execute very solid Intermediate flying!
We had some windy days and some of the rounds where flown in strong cross wind, that drain
some extra power as the rudder is in most of the time, adding more drag.
Being one of the judges, I've seen all the details and it looks good ;-) Electric works, period.
/Lonsan

Hi Lonsan !

Nice hearing from you. We had some excellent days at the Nordic Championships right ?

Yepp. Plane worked excellent. Alot of power and enough duration. My flying has even improved due to the performance and stability of the electric powerpackage.

And yes; the Jeti Spinn 220 has braking. Works very well.




best regards

Hi Ketil.... Glad to hear that it all worked for you....

How did the Nordic Championships go? Are there any results/photographs of the event available?
Wayne

Bernd Beschorner had a 40% electric Raven at the TAS in 2008. He placed 3rd in invitational. He is the guy that knows a lot about giant scale electric setup.

Posted By Wayne Matthews on 08 Apr 2011 11:54
Hi Ketil.... That is some good news. Please keep us informed of your progress & flight tests.

I have discussed with our new Rules Committee Chairman, Pete Castine, the possibility of allowing ONLY electric engined models the option of landing in between sequences to change batteries, because of the "nature of the beast".

If this is acted upon, it would not become a rule before 2013...but it is being seriously considered.

Best regards, & safe flying.
Wayne

Hi Wayne,

Is possible landings between sequences now finally proposed for electric drive in the 2013 rules process? Especially needed for advanced and unlimited I belive.

best regards
Ketil

Hi Ketil.... To answer your question frankly, we did put forward the proposal to the Rules Committee earlier and after their investigation they advised us of a few problems.

Firstly, although we would definitely like to see a forward push in electrics, if such a rule (i.e. landing in between sequences to change batteries) came into effect, we would receive a RASH of objections from the gas pilots who would want to do the same so that they could carry a smaller gas tank on-board.

Secondly, if landing in between sequences was allowed for both types of power supply, the time involved to do so would significantly cut into the available time for flying sequences at a contest. For a larger event with many pilots, it would be even a worse situation regarding time with the various classes.

So, as of now, after the investigation, we will not be putting such a proposal forward during this rules cycle. It would certainly create many issues already identified & also possible unforeseen ones.

Regards,
Wayne

Not to worry. I am sure that with the rapid advancements in electric technology, there will be adequate power systems available soon enough. I can see definite advantages to an electric setup, from smooth transition to better power, more efficient prop designs, less vibration, etc.

Is this something a CD could request as a waiver at his contest for the time being? (allowing electrics to land and change batteries after the first sequence)

Kevin

I agree with the Committee's decision. If you do it for one type of power then you must o it with the others. You could allow the CD's to request a waiver but I would first ask the RD's about what is flown in their regions and go from there.

Wow, I really moved up to gassers because I was tired of all the electric stuff. Make it stop. LOL

Hi Wayne,

Thanks for the reply. Agree to most of the issues and concerns rized. However if (?) IMAC as organization wants to promote the use of electric a time limited transition phase with adapted rules would help alot. Say a two to three seasons. This will speed up the developement and testing of planes and powersystems with increased performance and flight time. The fact is that we will in that case do the testing in an actual competition enviroment. Just think back to what TOC as a single yearly eventy at that time did for the developement of larger gasser planes and equipment.

Up to Intermediate electric drive is not a big issues with present technology. New kinds of issues and challenges starts at Advanced. I am pretty sure that people like myself will find viable ways and solutions anyway for the higher classes but it would be nice to have some incentives through the rulebook to speed up the process. Also to push the manufacturers.

best regards
Ketil

Just another way to look at it.. Isn't the incentive already there?

It is time to develop an electric setup capable of longer flight times to be able to compete on a level playing field.

FOr me, that is the biggest short coming for larger electric setups.. the flight time.
I see the incentive is already there for the manufacturers to develop products that can compete with gas set ups...

again, just looking at a different angle...

If you went to a single sequence like you do at the shootout, there wouldn't be a problem competing with electric power in IMAC. And/or allow pilots to land, change batteries and finish the second sequence in each round.

Yes I do agree Howard.

Curtis; yes the problem with higher classes is flighttime. This due to the larger planes and average power / energy needed for advanced to unlimited. Berschoner did that with succsess but with a very costly setup and well assisted by sponsors as a pure showoff.

I do not belive that todays inherent competition with gassers is enough as incentive.

One example is max amount of cells for motors and speed regulators. Most manufacturers limit to 14 cells most likely due to the EU LDV directive which says max 50V AC and 75 V DC before personal certification and special conciderations is necessary. Possibly also due to rated voltage on most common used components. However within the LDV directive it should be possible to use up to 16-17 cells. Why do I mention this; because higher voltage with same energy contend is in many cases (dependendt on battery) the easiest way to save weight and increase flighttime. But; the manufacturers need to make equipment prepared for it.

Airframes from 35% and upwards where easy access to batteries is arranged. Lighter airframe not dimmensioned for gasser vibrations etc etc. List of possible improvements is long.

To create a marked for such adaptions and improvements for larger planes incentives in the IMAC rulebook would also help.

Ketil

Ketil, how many minutes are you comfortably getting with your current setup?
Regarding weight is your current setup lighter than your wet setup with or without fuel?"
In the pattern world where about 75% have switched to electric as max time would be about 8 minutes weight is generally higher than the wet setup without fuel but probably less with fuel.

Thanks,
Stuart

Hi,

I get 8 1/2 minute from takeoff to landing. Clock runs all the time. Stays within 80% with sensible throttle usage for Intermediate. In Advanced I use more power and energy pr minute and more flight time.

Ketil

The voltage limits are generally in place to keep power systems from exceeding the level at which a short circuit could stop the human heart in dry air conditions. This is the reason people keep pushing the amperage higher and higher to develop power.

Pretty sure that anything higher than 12s on a Li-Po has the ability to potentially kill you (as in actually dead on the spot) if handled incorrectly.

Cool ! Now I want one !!!!!

That's just how us Red Necks Roll !!!!!!! Hey Ya'll watch this !

Posted By Mark Mcclellan on 12 Oct 2011 7:54
That's just how us Red Necks Roll !!!!!!! Hey Ya'll watch this !

Yep, right before the plane re-kits itself

I fly in the NW Division
In 2009 I flew and electric Hangar 9 33% Sukhoi in basic with an all Turnigy power system.

For the last two seasons I have flown Sportsman with a Hangar 9 35% Extra 260, Hacker A100 motor, Jeti Speed Controller and Turnigy batteries. I used the same 3 sets of batteries for both seasons.

I am currently building a 42% Slick 540 for the upcoming season. This will also be electric. The Slick will be extra light in order to carry 4 6 cell 6000 mAh batteries. This should give me enough battery for two intermediate sequences.

Posted By GDryer on 05 Feb 2012 22:49
I fly in the NW Division
In 2009 I flew and electric Hangar 9 33% Sukhoi in basic with an all Turnigy power system.

For the last two seasons I have flown Sportsman with a Hangar 9 35% Extra 260, Hacker A100 motor, Jeti Speed Controller and Turnigy batteries. I used the same 3 sets of batteries for both seasons.

I am currently building a 42% Slick 540 for the upcoming season. This will also be electric. The Slick will be extra light in order to carry 4 6 cell 6000 mAh batteries. This should give me enough battery for two intermediate sequences.

That is a very impressive achievement Geoffrey. Can you please keep us up to date on your project?
I am sure it will be very interesting to follow what you are doing up in Canada.
Thanks,
Wayne

I would love to see a parts list to include the charging system along with lots of pictures

I've been seriously considering the following:
Hacker A200
Jeti SPIN 300 ESC
7s4p 5000mah Li-Po.

The only problem with this setup really is I don't think I'll have enough batter for 2 Unlimited sequences.

Oh.. this is for a Hempel 40% Yak-55 as well. All up weight RTF should be in the 36-37 pound range with this setup.

Posted By Gil R. Major on 06 Feb 2012 9:27
I would love to see a parts list to include the charging system along with lots of pictures

Here is the link to the build thread on the electric Hangar 9 35% Extra. I think I talk about the charging system and just about everything else.
http://www.rcgroups.com/forums/showthread.php?t=1157267

Build Thread for my 33% Sukhoi
http://www.rcgroups.com/forums/showthread.php?t=933906

Below is a video of me practicing for the 2011 IMAC Season
http://www.youtube.com/watch?v=qj-wTu_54aE&feature=youtube_gdata_player

Posted By Doug Cronkhite on 06 Feb 2012 20:58
I've been seriously considering the following:
Hacker A200
Jeti SPIN 300 ESC
7s4p 5000mah Li-Po.

The only problem with this setup really is I don't think I'll have enough batter for 2 Unlimited sequences.

Oh.. this is for a Hempel 40% Yak-55 as well. All up weight RTF should be in the 36-37 pound range with this setup.

Don't you mean 14S2P?

The biggest challenge is that the extra weight of the batteries must be subtracted from the plane. Most ARFs are built to withstand the vibration which is overkill for an electric motor.

The estimated weight of my 42% Slick is 32 lbs including 4 6S 6000 mAh batteries (12S2P) This should be plenty of battery for the intermediate sequence but a higher class is unlikely.

The Hacker is a great motor but I think that a geared inrunner like a Neu motor may be slightly more efficient.

Posted By Wayne Matthews on 06 Feb 2012 8:08

Posted By GDryer on 05 Feb 2012 22:49
I fly in the NW Division
In 2009 I flew and electric Hangar 9 33% Sukhoi in basic with an all Turnigy power system.

For the last two seasons I have flown Sportsman with a Hangar 9 35% Extra 260, Hacker A100 motor, Jeti Speed Controller and Turnigy batteries. I used the same 3 sets of batteries for both seasons.

I am currently building a 42% Slick 540 for the upcoming season. This will also be electric. The Slick will be extra light in order to carry 4 6 cell 6000 mAh batteries. This should give me enough battery for two intermediate sequences.

That is a very impressive achievement Geoffrey. Can you please keep us up to date on your project?
I am sure it will be very interesting to follow what you are doing up in Canada.
Thanks,
Wayne

Thanks Wayne.

I started IMAC with an electric plane because all of my aircraft were electric. Since then it has almost become a necessity in our area because gas friendly fields are disappearing at an alarming rate. Noise of course is the major culprit.

I'm not sure about electric. I flew F3A pattern and one of the reasons I left it was because I missed the sound of a real engine. Come'on guys. Don't run me out of here too. LOL

Yeah.. I meant 14s2p.

My reasoning for wanting to fly electric is purely logistics. I have an electric only field 10 minutes from my house. The closest gas field is 45 minutes (without being someone's guest at the military field).