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Sep 18, 2016, 04:00 AM
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Build Log

Byron A4 skyhawk build EDF conversion


Hey guys. I've decided to start building my Byron A4 skyhawk. I picked this up a while ago from a friend at a very reasonable price. Its sat in the shed for a couple years and now coming into the build season I think its time to make a start. Want to build it as light as possible and plan to make a few changes. Ailerons will get a servo in each wing, the elavator will get the same treatment as Greg Covey's with the servo in the rear and im sure some other things along the way.

I have the Byron fan setup with a 560kv outrunner id like to stick to 10s just my preference. The Byron setup yields 58 amps 2028 watts and wieghs 1.5 lbs was offering roughly 15lbs thrust using luggage scale.

Also the CS 12 blade 120mm option on 10s weighing 2.4lbs. I've got to recheck my numbers but I think it was 110amps 3825 watts. It would require building some ducts for it though, which adds more wieght.

I was considering not using balsa to sheet the wings and just use glass cloth and epoxy. I've done a search for other Byron kits to see if this has been done but have so far come up empty handed. I was wondering what yyour thoughts were?
Last edited by Shane Sunday; Sep 26, 2016 at 04:08 PM.
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Sep 18, 2016, 08:46 AM
Do it Right, the first time!
CoolerByTheLake's Avatar
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It would require building some ducts for it though, which adds more weight.

I just had some intake ducts built by Air Sally and they are 17" long, and weight 5.5 oz

Considering the increased performance you'll get,it's a no brainier!
Sep 18, 2016, 10:02 AM
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Lt599's Avatar
If you have the original Byron foam it is a high density injection molded foam that was designed to either glass or use an iron on covering directly without balsa sheeting.
Sep 18, 2016, 11:23 AM
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thank you guys this is the kind of things I was looking for. I think perhaps I will glass the wing tips as these always get messed up on my models. At the moment I'm taking stock of everything and getting an idea where to start. Anyone who has aimed for 12 lbs came closer to 15Lbs. we shall see.
Sep 18, 2016, 04:08 PM
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Just a few pics of the inventory so far.
Sep 18, 2016, 06:51 PM
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Kevin Cox's Avatar
Nice Shane!
I finally ran mine on 10s and had more vibrations than I like. Is your fan pretty smooth?
Sep 19, 2016, 01:37 AM
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Good morning Kevin. From what I remember it ran very smooth. Having said that, I'm going to build another test bench and get some new readings. I've been on the lookout for some new batteries I reckon somethung in the 45c area.
Sep 19, 2016, 04:45 AM
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Kevin Cox's Avatar
Hello Shane,
I guess I might try removing the spinner and run it again. My test was on 30c packs and I wanted to try 12s but I was uncomfortable with the vibs at 10s.
Sep 19, 2016, 08:07 AM
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jhaywood's Avatar
You will want to glass the entire wing with 3/4oz cloth. If you are ding prone, a strip of 2oz cloth down the leading edge will help. Add a hardpoint in the wingtip for a skid since A-4s like to skin wingtips.
Make sure you ditch all of the factory control linkage, it is all junk. The aileron servo mounts in the nose and used Nyrod back to the sloppy Byron plug in aileron connectors. Mine was set up this way and it literally had +- 1/4" for neutral. The stab setup was even worse. It uses a soft 4-40 piece of all thread or a bolt for the control horn hooked to a nyrod. I could move the stabs up and down and inch!! and the servo would not move. There was no slop, it was all flex!!!
I have already cut split flaps into one wing panel and moved the aileron servo outboard. I cut the spars on the stabs to get them off and will probably make a mold to do a composite stab and use a real stab spar set up with a modern linkage.
Rudder servo will go in the fin of course and the steering servo up front, maybe where the aileron servo goes since it a nice little hatch molded in.
Sep 19, 2016, 02:49 PM
EDF all the way!
bruff's Avatar
Getting ready to start mine.( I have two kits) Adding duct will not gain you anything with the Byron fan. I'm running 12S with a Het 800 590Kv motor. Going to glass wings no balsa other than stock.
I'll be following your build.
Bob
Sep 19, 2016, 03:34 PM
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Wow so many people building these big birds. Thanks for chiming in. I had heard the linkages were pretty bad. I reckon a servo in each wing should sort that. Bob have you got a build thread? I'd like to see what you do. I'm going slow on this. I started installing the retracts just to see and the leg get jammed up on the balsa spar which leaves the wheel hanging out of the plastic blister by say 2.5 cm. should they be sticking out?
Sep 19, 2016, 05:51 PM
EDF all the way!
bruff's Avatar
No build thread yet. Finishing my ESM Texan II then on to the A-4. Using electric retracts for it also.
Bob
Sep 21, 2016, 04:06 PM
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Oooooooo. The texan 2. Thzt thing just looks fast. I've sent a set of retracts back to Horrizon Hobbies because the PCB packed in. Well I'd taken it apart to see if I could sort it out. I also attached another PCB to the unit and it worked great but wouldn't fit in the unit. They just got back to me saying they are awaiting a replacement PCB. Just great customer service. Although I will say this, I've had more troible with the expensive retracts than the cheap ones.

I've been doing research, head scratching and some testing. The jetfan 100 puts out as much watts as my CS fan but less amps. Also more than the Byron fan but puts out more amps. Hmmmm. These sorts of things keep me up at night. I also tested brown paper and PVA vs glass cloth and epoxy. Same size sheets and enough to wet through. Weight was the same at 2g durability seemed very similar too but the glas was stretchy. Tearing is where I figure it counted and the brown paper tore like paper... go figure. So did the glass cloth but it was a bit more tough. So looks like glass cloth for the win.

can anyone tell me which hysol I should look for please
Sep 21, 2016, 04:11 PM
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jhaywood's Avatar
Hysol 9462 or E-20HP
The 9462 is 1:1 mix but sloooow. E-20HP is 2:1 and sets up hard in about 2 hrs. The 9462 is definitely an overnight cure.
Sep 21, 2016, 06:27 PM
EDF all the way!
bruff's Avatar
I use E-20HP
Bob


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