ELECTRIC BERGEN

[v22chap]

Cool
Why did you mount the tail servo forward??? because of weight balance ??

[JBajkor]

Cool
Why did you mount the tail servo forward??? because of weight balance ??

Yes. When it was set up with Zenoa26, it had NO nose weight. Moving the servo forward along with Rx batteries up front made it balance fine.

When I converted to electric, I moved the Rx batteries back and left the servo. Still balance fine with no dead weight
Joe

[JBajkor]

I went back to look at Zozie's post and some of the numbers there are wrong.

Blades are NHP800
The weight is 14lbs.
Batteries are 10S, 6600mAh
10 min flight uses about 3Ah (about half capacity)
The longest flight was 15 min requiring just over 4Ah put back in.

The heli has logged 11 hours flight time as electric.
Joe

[v22chap]

Those are great looking figures on flight times.... do you have any vids of it performing???

[JBajkor]

Those are great looking figures on flight times.... do you have any vids of it performing???

Sorry, no video, but it would be boring anyway. I just fly it scale-like with the occasional loop and shoot autos.
The current is low because of the mild flying style.

I have an electric Xcell for the wild side. For comparison: the Xcell will use 3Ah in 5min and it is only 10.5lbs.
Joe

[v22chap]

Scale like is not boring ,,,, matter of fact that is more what I am looking to use it one.

[Greg Alderman]

OK...I wasn't going to post this until after the first test flight today, but...I couln't resist giving a little update

I am just using the standard Nitro frames right now so it isn't the prettiest...but Chris is making me a set of frame blanks that I can cut out as needed for battery and ESC mounting, etc.

The batteries need to be moved about 3/4" fwd to get the CG perfect...but I have a feeling if I took the Horizontal fin off it would just about be right. my uncalibrated arms says if feels a little lighter that my other Bergen 90 without fuel...so I am thinking right around 10lbs 4oz give or take...

I still have the 4000mAh Duralite RX pack and the 6v HD regulated swith...I can save a couple of oz by going to a 2000mAh pack and the standard regulated switch...I also will probably put the standard white Bergen gear back on which is a little lighter than the gear that is on it now...

But...I am hoping this will be a good flyer...as I am really wanting to convert an Observer over to electric soon...it is needed more than an E-Magnum as the AP guys really like the smoothness of electrics...

Anyway...the test flight this afternoon (weather permiting) will be with the following set up...

Bergen Magnum
Acro 32-4 motor (with a custom mount made by Malorie)
Hacker 77 ESC
2 X FlightPower Evo 20 5S1p 4350mAh
690 V-blades, paddles and tail blades...

so I guess we will see how it goes!

Won't have any video today...but will try to get at least a still photo of it in the air...

[llamatrails]

Greg,
Can you describe the motor/gearing a bit more ?

What count pinion did you use ?
Is it just mounted on the motor or is there some support from above it, hidden by the canopy ?

Can you post a pic with the canopy off for us to see how you set it all up inside ?

[Greg Alderman]

Yeah I will post more pics later...at work now...

Running 12T pinion...using normal Bergen Triple Bearing block assy to hold pinion at top...

Theoretically...the motor is a 415KV motor...so at 10S, lets use 90% efficiency factor and gear ratio of 7.5:1...

415KV X 37v X .9 / 7.5 = 1850 head speed...probably should be more up around 2000 to be really crisp...but thought this would be a good starting point...can try a 13T pinion later...

[v22chap]

Looks great Greg ,,, good luck on the maiden
:glasses: :glasses2:

You actually WORK ,,, that is a four letter word around here ,,,watch it. :noteworthy

[JBajkor]

Great job Greg!

Out of curiosity, why did you use a 32-4 instead of 32-3?

Joe

[llamatrails]

Probably because of the following:

32-3 has a kV of 555 rpm/v so a 12T would have given a headspead of 2464.

555kV x 37v x .9 / 7.5 = 2464

[Greg Alderman]

OK...Had sort of a maiden flight today...I had the Hacker 77 set up according to the instructions...but the 32-4 didn't like these settings...Called Bobby Smith and he told me the correct settings...so I will try again...but...it did fly and I hovered it and did some gentle fwd flight for about 5 minutes and it used up 1300mAh at a head speed of 1800. It was very smooth at this head speed...

One of the settings I had which I didn't mean too was Gov mode and it DOESN'T like gov mode!!!! But since I didn't bring the directions with me to the field and I didn't remember how to switch it back I just flew it at is...but the 1800 was at a throttle line of 60 at 70 it was up around 1900...

I ordered a Hacker programming box today and it should be in on Saturday so hopefully I can fine tune the ESC then...

like I said I don't have a working digital camera at the moment so all I have is one quick low quality picture of it in a hover...

[MarkWebber]

That's great! Even better once you get it dialed in, I'm sure.

I know this guy that might be able to get some good pics for you :wink:

[3drcheli]

That is looking great. I can't wait to hear more results of how it goes.

Kevin

[WillJames]

SWEET Greg!! Lets get some good video at the SE Event next weekend!!

[BobbySmith]

Real nice GREG!!!!! that motor and Batteries look right @ Home!! cant wait to see it next weekend
How much did it end weighing?
Bobby

[Greg Alderman]

Put 4 flights on the E-Magnum yesterday...flying it at a head speed of around 1850 and she is very smooth...seems to have as much if not more power than the YS91 I pulled out of it.

I like it already enough that I am playing with the idea of converting my other Magnum over also! But I really want to work on converting an Observer over...think a lot of AP guys would like an electric Observer!

Still have to weigh it...need to go buy a fish scale today...

Hopefully the video that was shot yesterday will get posted today...too bad it is just of me flying it! :( :oops:

[MarkWebber]

seems to have as much if not more power than the YS91 I pulled out of it.

Awesome! Can't wait to see it.

[Greg Alderman]

Bobby...My "calibrated" wrist needs recalibrating I guess... :arggg: :arggg:

I went out and bought a scale...and my Nitro Mangnum weighs in at 10lb 8oz ...the E-Bergen comes in at 11lbs even...Now the nitro version didn't have any fuel in it and the E-version had both 4350mAh packs in it...not sure how much less the 3700mAh packs weigh but that would be one way to drop a little bit...I am going to change the Orange Landing gear to the OEM Bergen ones as they are little bit lighter also...

By the way I charged my packs this morning and my 5 minute flights at 1850 headspeed are taking right at 2.3 to 2.5amps out of the packs...I am going to go 6 minutes next time I get a chance to fly it...and see how close that puts me to the 80% capacity rule...

Maybe with the cut outs in the frame plugs Chris is making me and the lighter gear and batteries I can get it down to 10.5 lbs...I think that would be a god weight to aim for...

Now if we can just get the video posted...the server that it was trying to be uploaded to is being stubborn! :D

Already pricing new motor and ESC for my other mMagnum!!!! :glasses2: :glasses2:

[TopView]

Guys, I would like to change my Industrial Twin into a electric version. But i don't think it would be possible, to big to heavy.

Have any suggestions.

Rene

[v22chap]

Rene
In a search for motors I found some axi's that were two motor together ... didn't pay to much attention to the KV but it was talking about very large scale airplanes.
Might be good to plug these into the forumula and see .Some of the German (or some other nationality) guys had a very large Jet Ranger at IRCHA last yr.

Greg can tell you more about them and their setup as he was tenting with them .

Greg is also working on doing an Observer
Good luck in your twin conversion quest

[Greg Alderman]

Rene...haven't looked into anything that big...but there are motors out there that are flying 50lb 3D planks with ease...not sure how many cells or anything...

[TopView]

That sounds good, i also read an artical about the big Jet Ranger. What i remember is that they build a special engine just for the Ranger. I would be great if i could use a stock engine.

The quest goes on.

Thanks, Rene

[Greg Alderman]

OK...video in the video forum now...I thought Henry was saying my head speed was 1850...but now that I see the video the head speed was 1815...still want to bump it up around 1900...

this was the 3 flight on it and the second flight for this set of batteries...

http://www.helifreak.com/viewtopic.php?t=22425