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Old Jan 29, 2013, 06:34 PM
Multi Rotor Maniac
Stunt Double's Avatar
Australia, VIC, Melbourne
Joined Oct 2007
2,802 Posts
I havent come across this guy before. How does he actually test CG in flight if he doesnt agree with the dive test method?? Personally I think the dive test is essential, I use it on all aircraft from slopers, wings, edf and fpv planes.
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Old Jan 29, 2013, 06:59 PM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
argo-2's Speedo build.

...and getting back to this thread's purpose (from my ramblings on the last page), here's my incantation of a Speedo build (still waiting for aileron servos though):
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Last edited by argo-2; Jan 29, 2013 at 09:14 PM.
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Old Jan 29, 2013, 07:00 PM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
Quote:
Originally Posted by Stunt Double View Post
I havent come across this guy before. How does he actually test CG in flight if he doesnt agree with the dive test method?? Personally I think the dive test is essential, I use it on all aircraft from slopers, wings, edf and fpv planes.
Best he explains this....

http://louisvillesoaring.org/media/G...g%20System.pdf
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Old Jan 29, 2013, 07:48 PM
Registered User
United States, CA, Napa
Joined Dec 2010
213 Posts
I am a new builder, also putting a Speedo together right now. Thanks so much for your excellent photos. Your post really helped me out!

The servo covers that came with mine were so warped that they are unusable. Had to order some replacements.

So it looks like the round file takes off enough material right where the ele control rod exits the fus, just to prevent the connector from contacting it during movement.?.? Is the relief groove you filed around 5 mm in depth with your set up?

Many thanks.
Scott
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Old Jan 29, 2013, 08:29 PM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
Quote:
Originally Posted by curdman View Post
I am a new builder, also putting a Speedo together right now. Thanks so much for your excellent photos. Your post really helped me out!

The servo covers that came with mine were so warped that they are unusable. Had to order some replacements.

So it looks like the round file takes off enough material right where the ele control rod exits the fus, just to prevent the connector from contacting it during movement.?.? Is the relief groove you filed around 5 mm in depth with your set up?

Many thanks.
Scott
Hi Scott,

You're welcome for the pics.

Re: The relief groove: yes exactly to allow the connector 'barrel' to go forward for down Ele. I filed then tested with my Tx, then filed some more. Don't really think it matters if you remove too much (though stop filing when you hit the wing saddle ).
Picture worth a thousand words, looks about 3mm.

Cheers, Brendan.

PS: Have you tried pushing the Ail servo covers down at the corners, they do flex. Or are they just too warped?
PPS (edit): Make that 2.5mm. By the way as per another great post on this thread, use CA to harden the edges of any hole you drill in the balsa (eg: elevator for horn) or ply (Eg: Wing for aileron covers). I tape off one side of the hole and then fill the hole with CA (cheapo CA is fine). It soaks into the fibres making the balsa into a sort of fiberglass. Even with this, go easy screwing the horns down. If the Balsa starts to crush its a one way trip.
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Last edited by argo-2; Jan 29, 2013 at 08:37 PM. Reason: PPS
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Old Jan 29, 2013, 08:49 PM
Silent Flight
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United States, CA, Cypress
Joined Jul 2005
3,951 Posts
Excellent job Brenden. I love your attention to detail, and look forward to your completion and maiden. What kind of ballast are you considering if any, and how do you look to secure it?

-Jonathan
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Old Jan 29, 2013, 09:27 PM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
Thanks Jonathan for the kind words.

Ballasting a slope soarer will be new to me as I've not gone down that path in my 6 months of slope soaring (I was/am an electric park flier before that). Which is to say I've not really given it too much thought other than: "cool now I've got some free-space under the the Speedo's CG". It was kind of a spin-off of wanting to get everything as far forward as I could.

One aspect of my build I forgot to show was that I beefed up the wing-saddle area with 2 lengths of 3mm CF tube I had on-hand. So its strong under the wing. Also those wing-bolt T-nut installs are incredibly solid (hence my challenge getting my Rx under the forward one). Given this, the easiest way off the top of my head would be to make an EPP plug to fit nicely (tightly) in the wing saddle area and then insert a ballast tube into that plug. Either that or make an EPP plug for each ballast weight, which in the long run would probably be the easiest.

What sort of ballast weight are folks using with their Speedo's?
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Old Jan 29, 2013, 09:35 PM
Silent Flight
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United States, CA, Cypress
Joined Jul 2005
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Argo, far from your quality of work, but here's the extreme answer to your question. It's currently a stalled work in progress but maybe I'll stick it back on the bench after I finish what's currently on there.

The Frankenspeedo 1.2


-Jonathan
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Old Jan 30, 2013, 01:17 AM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
Haven't gone through all of your Frankenspeedo build log - but from what I've seen that's friggin amazing! A kilogram of ballast wow &

Rather than pull this thread off track I'll post further on your build thread. However I salute you sir on the challenge you have set yourself!
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Old Jan 31, 2013, 12:13 AM
Maiden>Confident>Cocky>Crash!
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New Zealand
Joined Feb 2010
558 Posts
Finished (maybe)

Aileron servos arrived from R2 this morning so my Speedo is finished. Problem is that one of them (they are for the ailerons) was erratic on first powerup. Seems fine now, but...

So interesting CG now I'm finished. I builtin 45gms of lead into the nose and had a 2+1+1 battery setup. My finished CG has come out at 73mm. So no more lead will be going into the nose. Final weight is 410gms. Only additional item in the plane is a lost model alarm (in the nose) but this is only a few gms. She's a very smart looking glider when finished. I used a few strip of signwriter's vinyl to break the base colours and also as a wing joiner. I was going to maiden with a CG of 78mm, but that requires 4gms of lead at the tail so I might just give a CG of 73mm a go and see how she flies. Easy enough to tape some lead to her arse at the field

Some finishing pics to complete this particular Speedo build...
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Last edited by argo-2; Jan 31, 2013 at 12:19 AM.
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Old Jan 31, 2013, 11:32 AM
Registered User
USA, CA, Pismo Beach
Joined Oct 2007
1,367 Posts
Looks very nice, argo. I'm curious how you like those servos. I had a couple a while back and though I liked the metal gears and how thin they are they seemed to have a lot of backlash making for a sloppy neutral or return to zero. They are a bit of a challenge to mount but that can be accommodated.
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Old Jan 31, 2013, 12:56 PM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
558 Posts
Hi Greywing

It seems my experience is the opposite to others in that my Ele servo from Hobbyking is very good, whereas my Ail servos from R2, I'm having problems with one of them.

The HK servos I received are very good (I bought three), perfect for my sloping. My Ele neutral is consistent and the slightest movement in the Ele stick causes a movement in the Elevator - can't ask for more than that!

The reason I ordered two more servos from R2 (Eurgles) was that I killed one of the HK servos I ordered for my Ailerons (I ordered 3 Vigors from HK). I killed it by getting glue into the output shaft when building an epoxy sleeve.
HK was out of stock so I ordered the R2 ones. These are identical to the HK's Vigors except the servo wires are shorter. Trouble is I think one of them (from R2) has a dirty potentiometer as at one point it went a little wild.

Sorry long winded reply. To boil it down - if you get good Vigor/Eurgles they are perfect. Trouble is out of the five I have, one of them is bad one (maybe) and unfortunately its now in my wing
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Old Jan 31, 2013, 01:08 PM
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Joined Oct 2007
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Yeah, mine were the Vigors from HK too. Actually I also had three and the results were kind of variable which implanted a little mistrust. One was very tight but the other two were a little marginal. In spite of their strange shape they certainly are thin and after you figure how to mount them, the size is nice.

Anxious to hear about your flight test!
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Old Jan 31, 2013, 01:10 PM
Silent Flight
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United States, CA, Cypress
Joined Jul 2005
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Brendan, I've had some mixed experience with Eurgles as well. Our local hobby shop used to stock them but has since discontinued them due to some issues with them like double centering. That said, I have only used them in the elevator function which I tend to give constant input into anyways as I hardly every just fly strait.

-Jonathan
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