Guys,
After seeing what Archie and Dennis have done with the smaller ECL planes I decided to try one a little bigger than the Barnstormer.  On the way home I acquired a Primary Force.  After trial fitting everything I deemed the EPF was going to be tail heavy.  I then cut out the fin, stab, and elevators and added ribs.  I cut the bottom off the fuselage aft of the CG and made up a CF pushrod.  I'll recover the whole thing with Monokote.  Anybody wanna guess what colors it will be?  I have a Scorpion 3020-16 that should be big enough.  I really think that my 3014-22 will be up to the task also.  It will be under 40 ounces so I'll be able to use .012 lines. Enjoy the pics.

PS - This is why the interpretation of the BOM rule the AMA has is ridiculous.

Lee,
When Russ heard why I wanted the PF he gladly donated it!  ........NOT!

Guys,
<snip>

PS - This is why the interpretation of the BOM rule the AMA has is ridiculous.

I note my $1 thread in the ARF forum!

I agree your 3014-22 would also be a good match. My 3014-16 reterminated as a "Wye" with kV=725 flew the Nobler just fine --except the overall kV was just a hair too low. But the motor can handle that size plane and save an ounce over the 3020's.

Dennis said;
"... Russ G. WILL be.... speechless!"

Impossible!
Mike G       

I am curious as to how you mounted the battery etc. How about a closeup pic of the front end?

Nice job Crist, to bad work kept me from coming out and seeing it Tuesday. Are you bringing it Sunday ? weather permitting ??

So is there an E- Harbinger in the planning stage 

Lee,
Yup, I'll have at Davenport this weekend.  Planning on going flying Friday evening too.

Dennis,
Thanks for the kind words.  Yeah, there is a goodly amout of power.  Now I'm trying to get all the mah out of the 2200mah batteries and convert it to useful thrust.

I flew it some tonight in my backyard with an ajacent field next to it.  I worked out using a 12 x 6EP prop spinning at 8500 on 58' lines giving me 4.9 - 5.0 sec laps.  On the last landing tonight, i hit a small tree because I drifted some when whipping it.  A big dent in the outboard LE, the motor mount tore off, and the fuse broke in half just aft of the wing.  Brought it in and 2 1/2 hours later its all fixed and ready to go again.  It does have some battle scars though!

I did notice tonight while i was keeping track of the mah used with my eLogger that the 4S 1550mah Rhino pack flying the Primary Force for 4 minutes would use the same percentage of the pack (80%) as if I was flying on my 2200 mah pack doing the full pattern for 5.5 minutes (80%).  So when I'm experimenting, i can use the 1550 pack and then use math to see where I'll be for the full pattern.

Crist,

I'm a bit concerned with your battery mount. Specifically I am worried about the battery connecting with the motor in a crash and rupturing one or more cells (don't ask me how I know this can happen). I realize that you have velcroed the battery to the fuselage but since you mentioned the the motor mount tore loose there could have been contact. Maybe a dense foam or balsa divider between the motor and battery would lend some degree of protection.

Just my 2 cents.

John

I would agree with this -- (don't ask me either  )  Well, I already posted the reason in another thread about puncturing LiPo's.  The quick and dirty solution would be a wedge shaped "deflector" between the battery and the motor.  If the battery goes forward, all you really need to do is make sure that it gets deflected past the motor.  Fortunately, I haven't had a repeat to test my theory.

Also make sure that no metal (  "j-hooks and rubber bands") can touch the batteries - even a little bit of vibration can cause a sharp end to wear through the cell's plastic envelope and short out the plates internally.  This is also not a pretty sight - the danger with that is the fire will still be attached to the airplane, at least until the rubber bands melt  .  That was the first thing I looked at on Crist's installation photo and it appears that there is plenty of space between the j-hooks and the cells.  On my "1/2E" I pushed some fuel tubing over the j-hooks to act as padding.

Good luck at Davenport, Crist -- actually I hope the weather doesn't drown out Davenport .... it doesn't sound good at this point.
Mike A

Crist,
I just converted my PF to electric, just added a front plate to mount the Scorpion 3020 so the rest is stock PF Arf---with a little added soaked-in oil from the year as a glow setup. I am using same setup as in Nobler (just a transplant), so we will see how it all performs. All up weight is 44oz, basically the same as the Nobler, so I'm pretty impressed that you brought yours in at 38.5 oz. Amazing that it would be possible to find about 6 oz in balsa.

Alan,
Great!  Please keep me informed as to the numbers that the Eagle Tree comes up with.

Well I managed to leave the house today without the Eagletree Data Recorder , but in any case everything was using the Nobler setup (timer, ESC, motor, prop, battery, lines). RPM on the APC TE 12-6 prop was, to refresh your memory, 7950 rpm. If anything, the PF was a hair faster than the Nobler--my Talking timer was giving me the 5 minute mark just midway in the clover, while the Nobler is just entering the clover at that point.

I drew 1600 mAHr out of the 4s2100mAHr pack, basically identical to recent Nobler flights. So within my understanding, the PF and Nobler are almost identical from today's flight. Fred timed me at 5.1s (nominal) a lap. I might prefer 5.0 s once I retrim the plane. Seems to be a slight warp--maybe a consequence of storing the PF up in my attic since last fall (2007). Not much. Also may  need a bit more wingtip weight without the glow engine cylinder head hanging out further than the battery.

My setup looks similar to yours, I am using liberal amounts of velcro to hold the battery on with some rubber bands to give a little more secure feeling.

I just put on the Eagletree in case the weather tomorrow is better than forecast!

alan,
Your numbers are what I'm seeing only I'm using up about 1750-1800 mah when using a APC 13 x 4 cut down to 12 and repitched to 5 and launched at 9600.  When I launch at 9400 (same prop) then I use 1600mah.  5.1 to 4.9 sec laps on 58 foot eye to eye .012 lines.

Crist,
I am curious why you are running modified props. I know this is a whole new world with respect on how to get thrust and good line tension everywhere. So that's why I am curious.

I have been tending to go to lower and lower prop rpm (higher diameters and higher pitches). I think these are more efficient but I am not sure this is significant or not. Plus what matters to most of us I think is that the lane hangs in there in the overheads. It is painful to fool around with props since it does take a fair amount of effort to zero in on the rpm you want. The APC12-6 TE has been good to me so far, but I do want to see what a 12-8 does (I have them up to 12-10!). So with that much effort to try out props, I haven't been inspired enough to look into cutdown or re-pitched props. This isn't to say that perhaps that might the best prop.

I would be curious if anyone has an idea of how to make this playing around easier to do. I really like the fixed rpm mode of the CC Phoenix series, but I am thinking that reverting back to low governor mode will make it easier to make field changes (in the timer). Of course I could bring a laptop to the field I suppose and leave it in the fixed rpm mode.

Crist,
While I haven't flown in super windy days---10mph or so is probably the highest (except at the Firecracker contest) and haven't felt any type of windup with my setups. The reason I think is the governor. To get a feeling how well it can work, just turn off the brake feature on landing!

I know flat pitched props are de rigueur for glow, but I am not so convinced in electric. Have you actually seen a difference there?

I would like to know more about hte function of the govenor in this regard. My curiosity revolves around the response, control time that the govenor takes to control rpm.Is it based upon smaples per rpm of the motor, or samples per time. It would seem to me,,that if it were sampling on an rpm controlled basis, then using higher rpm and flatter pitch props, would tend to enhance the control aspect of the govenor. However if the gov. samples on a strictly time basis with no regard for rpm, then it may in fact be better to use higher pitch props. All of this of course is with respect to the kv of the motor and your setup. But starting from scratch you could perhaps tailor more closely to take advantage of the govenor if this were known.

Mark,
The ESC is sensing the magnets passing by, so you can multiply the rpm by 14 (for my motors anyway).

I have no idea on the time constants the ESC uses to average these samples. So far I have seen absolutely no issue with holding the rpm--at least on the time scale of the maneuvers. There is some "grass" in the rpm measured by my Eagletree data recorder, but that  isn't associated at all with maneuvers. So for all intensive purposes the rpm is held constant. I don't see any sagging or surging whatever.