Sep 23, 2003, 02:06 PM
Castle's Chaos Corner
Bernie Wolfard's Avatar
A note on my Surprise 10. It was a fly away from a bad receiver battery while doing the thermal task. It was found about ½ mile from the flying site with the Fuselage broken in half and wing badly cracked.

The fuse repair was easy because the halves butted together while maintaining the alignment of the tail. I CAed the halves together carefully to maintain alignment, sanded about 2” past the break down to raw kevlar then covered the break with two layers of kevlar, one strip 1” wide, the second 2” wide. I put the wider strip over the narrow strip to hide the first pieces edges. I then covered the repair with a large shrink tube cut and CAed to size. Hitting the shrink tube with a heat gun forced excess epoxy out of the fabric, which I mop up with a paper towel. The result is a smooth light and strong repair ready for finishing.

The wing is another story. I cut a hole in the bottom of the wing in the middle of the cracks to inspect the spar, which appears to be OK. I used a syringe with a fairly small needle to punch through the top layer of glass and inject CA into the balsa along each crack. This stiffened up the cracks to where they seem as strong as the rest of the wing. I am contemplating filling the wing under the cracks with two-part urethane foam. On this I am of two minds; if I do it I will be more comfortable with the wings structural integrity but the foam will add a lot of off-center weight.
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Sep 23, 2003, 03:26 PM
Registered User
WimH's Avatar

Re: Re: Re: F5F on the cheap

Originally posted by soholingo

1. Not that much difference in 80a and 120a? Is that really true?

2. And when you say there is no differnce in props, you have to explain that better... there is a differnce in going from a 13x7 to a 14x9.5 so going to 18" should be even better.

3. Lastly what happened whith your pre damaged s7? What was the damage? How did you repair it? etc...

1 : Yes! Elementary my dear Watson, just calculate:

suppose a 4mOhm 10 cell battery ("Average" zapped RC2400) and a (good) 4mOhm ESC: Ecalc says 7 volts arrives at the motor @ 120A = 840watts in. @ 80 amps however, motor voltage is 8.8v , or 704 watts in. Lets not even consider that other losses ( wires, connectors,motor) are also (a lot) higher @ 120A compared to 80A.

This means a 50 % amps increase gets you less than 20% power increase. Unfortunately this 20% more power does not get you 20% more laps in F5B, 1.2 times the amount of power only gets you the cube root of 1.2 or 1.063 times (6.3% extra) the number of laps.Meaning if you fly 20 of them with 80A, just going to 120A will get you 21 and a bit if nothing else has changed. If you did 20.9 ( only complete laps are counted) with 80A you might get to 22. One, maybe 2 laps extra does not sound all that impressive for a 50% amps increase. The picture gets a little better for the good pilots of course...

2) Props:

Both the 13*7 and 14*9.5 props you talk about are Graupner. Their pitches are a lot lower in reality ( close to 13*5.5 and 14*7 or so). Put an Aeronaut 13*11 on your Bandit, it'll climb faster and use a little less current than the Graupner, effectively showing that bigger is not always better ( now where did I hear that before ) Getting the correctly matched prop for your plane and flying style is much more important. Of course there is a difference, but again, these are small if you have a good match to begin with.

3) My S7 was damaged in the mail when sent to the person I subsequently bought it from. ( 2.20m box reduced to 1.8m, wingspan is 1.96m: the tips were broken + some lighter damage) I had it repaired by a friend ( Tips glued on, missing parts replaced with balsa + glass cover+ spar repaired on one side).

I was flying the 22nd lap on my 4th competition flight with it when it started rolling, not responding to my correction, not responding to elevator up either. Dove straight into the ground ( 30cm deep) from about 30 m high. Fuse more or less ok; wing was separated from the fuse (plastic bolts gave way, but everything in front of the spar split open at the joint ad got crumpled, very difficuly to repair (unless you could put in a mould). Elevator split open (7-8cm) too. No other real damage.Still unclear about the cause. I had a test flight with it too, but less than 5 flights , even though they were wonderful, is a bit disappointing

Here's a pic:

The other tip was not completely broken, but bent a bit further inwards, that's where the spar was damaged. Rest of the damage was minimal ( a small hole and a 1cm crack in the trailing edge)
Last edited by WimH; Sep 23, 2003 at 03:42 PM.
Sep 23, 2003, 03:45 PM
Tragic case
davidleitch's Avatar

I have used two of the EM motors the Elios 37 and the Chronos 40. Physically they are a little larger than the equivalent Hackers. However they weigh within one oz. The cases have cooling slots to let some air in.

Initially I used an elios 37 on a spiro with 10xfaup and 14x10 prop. Was good for 65-70 amps and worked perfectly. This was an adequate brushless setup for sports flying.

However I wanted more so I switched to a Chronos 40 with the Reisenauer micro 5:1 gearbox. That motor costs the same as the Hacker F5F. The problem was that the pinion on the gearbox kept slipping on the motorshaft. Despite more than 10 attempts to secure it the problem persists today. The combo will have to go back to France.

Several people here in Australia are using the EM motors and in general they perform as well as other high end brushless motors. I also have one of their outrunners (twister 29) and it looks very well made although I have not used it yet.

Unfortunately to compete successfully will always cost money.
Sep 23, 2003, 03:49 PM
Registered User
WimH's Avatar
Originally posted by Flutterbug

Anyone ever used on of these motors and controllers. I
Electronic Model's controllers are Jeti OEM, almost identical to the Advance series, a bit less sophisticated than the Hacker (also OEM Jeti). I use a couple of them and I'm satisfied so far.

The motor's are probably as good as any other Hacker/Plettenberg/Aveox/Lehner/Kontronik etc out there. No personal experience here.
Sep 23, 2003, 04:17 PM
Castle's Chaos Corner
Bernie Wolfard's Avatar
David, Thanks for the info on the EM motors. I agree, to compete costs money. But at the bottom of the learning curve I don’t want to risk, nor can I afford right now, the best. My goal is to learn at a price I can afford rather than sit around waiting until I can afford the best.

The cost in Euros for the chronos is quite a bit less than a compairable Hacker, which is much less than a Plattenberg. In fact it seems like quite a value for a motor and reduction drive. As a note I had Google translate the EM website and it renamed the chronos to stopwatches ;-)

I assume you tried green locktite on your pinion gear.
Sep 23, 2003, 04:49 PM
Registered User
WimH's Avatar
Originally posted by Flutterbug
As a note I had Google translate the EM website and it renamed the chronos to stopwatches ;-)
That would be chrono's as in chronometers. Chronos/Kronos is/was/whatever the Greek god of time. ( = Saturnus). Elios/Helios is another Greek god, ( =Pegasus) . By now, you should have gathered that EM names his motors after Greek gods... No idea if it helps performance
Sep 23, 2003, 05:23 PM
Castle's Chaos Corner
Bernie Wolfard's Avatar
Should name them Mercury, god of speed. I made a mistake. The motors are priced seperatly from the gear drives. The combination is not so inexpensive.
Sep 23, 2003, 07:15 PM
Registered User
Lenny970's Avatar
As Soho said, one of the best low budget (well, medium budget) ways to go is with a used Aveox F10. You can usually pick up the motor and Aveox controller for about $250.

Good luck,
Sep 24, 2003, 06:41 AM
F3B enthousiast!
guillaume83's Avatar
hi Flutterbug,
i hope you emailed Electronic Model and not Model Motors,there's no such company in France.
if you check and scroll down for the Sun review i did,you'll see i am using one of their set up.
i don't think the controllers are Jeti (even though they look like it) because they have a Twin Cable system which the Jeti do not have (they have BEC and no BEC built in the controller,a very good option,you do not have to worry about getting a non BEC controller and think of what you'll do with it when you want to use BEC say in a different model)
hope that helps
Sep 24, 2003, 07:00 AM
Registered User
WimH's Avatar
Originally posted by guillaume83

i don't think the controllers are Jeti (even though they look like it) because they have a Twin Cable system which the Jeti do not have....(
I KNOW they are OEM Jeti's though. Not that it matters....
Sep 24, 2003, 01:55 PM
Castle's Chaos Corner
Bernie Wolfard's Avatar
Lenny, I'm game. Where do I get an Aveox F10 with controller for $250?
Sep 24, 2003, 02:00 PM
soholingo's Avatar
search the for sale forums. I have only bought a few brushless motors from vendors, and that was before I found the for sale forums...

Do a search for F10 in the forsale forum. Someone was selling some F series aveox motors the other day...
Sep 24, 2003, 02:18 PM
Enjoying the good life!
Aobid's Avatar
I've bought two used Aveox motors and I couldn't be happier, I'd just make sure the person whom you are buying from is reputable.
Sep 24, 2003, 05:40 PM
Registered User
Lenny970's Avatar
Originally posted by Flutterbug
Lenny, I'm game. Where do I get an Aveox F10 with controller for $250?
Well, here's one:

They do show up pretty regularly, so just keep your eyes open if this one gets snatched up before you get there!

BTW, how did your Avionik repair go?

Last edited by Lenny970; Sep 24, 2003 at 06:56 PM.
Sep 24, 2003, 10:29 PM
Registered User
Kevin Murray's Avatar
Originally posted by Flutterbug
Lenny, I'm game. Where do I get an Aveox F10 with controller for $250?
Flutter - I just bought a like new F-16 with a M260 ESC with the compitition upgrade (top shelf hand picked FET's good for 70A/110A peaks). Spotted it on the EZone just before NEAT. He had three Aveox F motor/ESC set-ups, $250 each.
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