BVM Electra ARF build and modifications - RC Groups
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Jun 12, 2009, 06:45 PM
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ralf dvorak's Avatar
Build Log

BVM Electra ARF build and modifications

Hi Guys,
here’s a short summary of my latest build. You all know how much I adore Bob’s sport jet shapes ... so of course I had to get his latest creation, his first venture into electric jets, the Electra - in ARF form because I plan this to be my everyday jet alongside my current EB.
All general design discussions aside (there will surely be more at the end of this thread) and all is to be taken as IMHO, ok?

This is a fantastic jet, IMHO a near perfect kit, but if you know me you can imagine that I cannot go along without a few BUTs . It’s not only about personal technique, but about a few refinements I’d suggest… just like tuning a near perfect car to one’s liking.
I have witnessed Rico flying his Electra performing fantastically a few weekends ago… stock build and setup… let’s see whether we can’t refine it a bit more?

Every screw onboard is metric now except where inevitable. I use the Air Blue retracts, plus a set of Bandit DuroStruts, Bandit wheels and brakes on the mains, and a Pro-Lynx custom nose strut.

I have not come across any hiccups, apart from one former being too wide by 1-2mm to fit comfortably, that was easily corrected. Every small item listed in the manual is provided and if you’re an inexperienced jet builder you better stick to the manual.
Kirk has already reported extensively on the kit building procedures here and in RCJI so I will focus on my alterations, ok?

Here we go:

The manual has the vertical fin glued on and the horizontal stab (slight anhedral as usual) built to be removable only when the tailpipe is removed first.
IMHO a no-go. M3 Blind nuts are repositioned into the carbon spars, 4mm bores respectively. Fixed with countersunk M3x16 bolts from below through the fuselage wall, still clean and flush, but stab now removes from the outside in a minute.
There’s nothing much I could do about the vertical fin because of a lack of mounting space and as apparently she fits into the Jet case with the fin on I left it like this, but the stab had to be modified…

The manual has you cut out a belly pan like on the Bandit family. I know where this stems from… the original Bandits had this as a necessity… I have it on my SBB, but I could have done away with it.
It’s ugly and a lot of hassle when you assemble the jet at the field. It is consequent with a Bandit spar but not with the Electra plug-in spars.
Now after mod the wings are on or off in a minute and secured evenly strong.

Inlets… the originals don’t fit into the inlet lips sufficient close enough to my liking. There is NO way that I could accept the fit without putty and sanding so a repaint is in order anyway. More later.

As I won’t be fitting an EVF the original ducting won’t fit nor will it be strong or suitable enough…
New plugs are in the making. First I wanted to reposition the engine… but I decided against it (although the mounting will be changed… …) because I know that there are quite a few of you out there that would like to re-engine an Electra without major (…) modifications. Check out my SBB modification carbon inlet ducting – these will be of similar style, available after some time.

She will be getting a DS-94HDT latest edition, Neu 1527-1.5Y self modified with new SKF bearings, pinned endbells and a Jeti temp sensor installed internally, Schulze 40.160, 12s SLS ZX 5000. This is imho THE carefree setup of the day, drawing about 4,6kW.

That’s it for now, more on the inlet ducting these days… I'm off till Wed.

Last edited by ralf dvorak; Jun 13, 2009 at 04:30 AM. Reason: wording
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Jun 12, 2009, 07:03 PM
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ralf dvorak's Avatar

next pics, java upload doesn't work

Last edited by ralf dvorak; Jun 12, 2009 at 07:19 PM.
Jun 12, 2009, 11:22 PM
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EDF Dork's Avatar
Nice work on the Mavrick... err I ment Electra . I look foward to seeing those pics of the Mods that your doing. It's allways nice to fine tune and EDF.
Jun 13, 2009, 12:50 AM
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Eddie P's Avatar
Ralf, Ralf, Ralf. Why do you do these threads? Every time I see this Bavarian craftsmanship in progress I nearly have to attempt to emulate it at home. This can be dangerous to my wallet (and ego)!
Jun 13, 2009, 07:10 AM
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birdseed's Avatar
Hi Ralf,

Regarding the mainspars, Do you have a securing 2 securing bolts, one from the top and on from the bottom?
If so are you putting an aluminium support on the top and bottom of the carbon spar.

(I have a ARF electra and i agree, the bolt through spar technique that BVM use is a right pain. I also have a kit electra Im building right now. Progress is stalled as I couldnt think of a clever way around the spar issue, one you seem to have solved)
Jun 13, 2009, 11:52 AM
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Robert Belluomini's Avatar
Ralf your killing me!!! Great idea on the wing mounting and eliminating the hatch
which is sadly needed for the mechanical gear setup, which can be a pain in the ass btw. When I bought my Electra they were the only game intown.

Jun 13, 2009, 07:04 PM
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ralf dvorak's Avatar
Originally Posted by birdseed
Regarding the mainspars, Do you have a securing 2 securing bolts, one from the top and on from the bottom?
Nope, just the one from below. It presses the spars against the top of the brackets as opposed to from the inside towards the face of the formers.
The bolt shown in the pics from above is there only to fix the alu piece in the right position for glueing and removed afterwards.
That sheet alu piece on the spar is only on the underside of each of the 4 spars. The securing bolt presses on the very edge of the carbon spar, I added the alu piece only because the spars are glued together from 2 of the usual BVM carbon spars and I added the extension only because I drilled at the very far inboard end of the bracket. Had I realised that the spar doesn't go beyond (or not even flush) that bracket I would've drilled on the other side of the bracket mounting bolts and omitted the extension. So, if anyone wants to emulate this: drill outboard of the bracket inner mounting screws!

I managed to do some more work today after having been to the field in the afternoon for 3 EB and one EBM flight:
Inlet ducting plugs sanded after the first layer cured overnight and sprayed with the second layer of polyester spray putty (fantastic stuff!!!!), just curing now. Tomorrow final sand and then one or two layers of 2k acrylic topcoat for final sanding and polishing.

Jun 15, 2009, 07:38 PM
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ralf dvorak's Avatar

et violà!

...two finished inlet ducting plugs. First two layers of wax are already on by now, pics are before wax.
Tomorrow first layup for my own Electra will go on...
I'll have CNC cut jig formers for installation in the pack later... first orders are in already
Installation with this one will be dead easy, as they can be perfectly glued together in the jig outside of the fuse, and the splitter sanded perfectly.
I think I can make insides white, silver, grey primer, black or clear (to see the carbon).

Last edited by ralf dvorak; Jun 15, 2009 at 07:43 PM.
Jun 15, 2009, 09:13 PM
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Ron101's Avatar
Dam!! Ralf
those look amazing... I'd hate to see the mess I'd make of that
skills bud, mad skills

Jun 19, 2009, 01:39 PM
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Robert Belluomini's Avatar
I like the end plates that bolt on to make the shiplap.
Jun 23, 2009, 05:55 PM
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ralf dvorak's Avatar
Ahh, so that's what it's called in english ... shiplap, hmmm. Yep, that's my preferred method.
So, here we go, 2 perfect inlet ducting halves joined into one outside the fuselage, it's a simple twist-and-turn slip into the fuselage... in fact they're installed and the hysol is just curing now.
I reused kit stock to make the fan mount, more pics of this tomorrow.
I've just handled the kit precut mylar for the thrust tube. I can't believe what a disgusting material that is, IMHO. I think it has to go.
Jun 23, 2009, 06:41 PM
This is what you call "mad building skillz."
Jun 23, 2009, 10:16 PM
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strictlyscale's Avatar
Beautiful work Ralf! Even your tools are spotless!!
Jun 23, 2009, 11:12 PM
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KHorton's Avatar


Very impressive work. I have done a few ducts but nothing compared to this. Couple of questions, First, How did you remove the new layups from the molds and how did you seam.
Secondly, I understand the epoxy poured inlet plates molded directly from the electra but how did you construct the black shiplap plates and what is there purpose. What material was used.
Thanks for your help.

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