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Old May 30, 2007, 03:59 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
6,940 Posts
Hi Invtrd, thanks very much for your reply.

The Medusas are very much at the front of my list, I have a 028 -056 - 1900 at the moment in another plane, it is a super motor, top notch. I was actually thinking of using the very same motor with their 1:4.4 gearbox for this plane, it's interesting to see your recomendation for the larger diameter type. The battery pack you used for motorcalc is the exact size I have! That's one h#ll of a prop needed there!

Chris
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Old May 30, 2007, 06:27 AM
confused heli pilot
United States, CA, Victorville
Joined Mar 2004
76 Posts
The larger prop will give you great climb out's to altitude quickly. You would have just slightly greater than a 1:1 power to weight ratio with a 3m sailplane. I just like vertical performance.

If you go with the smaller motor, run about a 16x10. It will still give you over 90oz of thrust at around 35 amps according to the calculator. This would still be a very nice set up.

it depends if you want to save the 70 grams difference between the motor sets. I would personally rather have the thrust and go with the larger motor since you have the batteries that will handle the motor already.
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Old May 30, 2007, 06:22 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,786 Posts
One thing to watch on this model... If you land hard at all, check the glue joints at the poly joints. Mine have failed after one slightly hard landing. I'll be doing surgery tonight. I have a new set of wings drawn for this thing... Wonder when I'll have a chance to build them...

Jack
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Old May 31, 2007, 03:44 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
6,940 Posts
Invrtd, thanks for the info!

Jack, where exactly did you incur failure (I would like to epoxy some carbon tows in as a pre-emptive strike.......)?

When you say a new set of wings - is that tips only, or are you unhappy with the entire wing design?

Cheers

Chris
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Old May 31, 2007, 11:08 AM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
7,786 Posts
My wing joints broke loose at mid span where the dihedral angle changes. I used a large pin and injected some CA glue into the joint, and it seems to be fine, now. There was no break in the spar system. I have drawn up a set of wings to replace these because the workmanship is so poor. When I first got it, the wings looked good. With about 50 flights on it, the sheeting joints are now humps iin the airfoil, I suspect because it's partly hot-glued together. I have a new airfoil I'd like to try out, and I'm thinking of bagging a set of wings for this model. I'll have to change the root section on the fuselage, but that's OK. If it flys as good as I think it will, I'll be makin' a mold... Who knows, I may build the wings from wood to keep in the spirit of what I truly like. I have been modelling a long time. This is aesthetically the most beautiful model I've ever seen... in my opinion. It's a shame it's not better made. The fuselage is absolutely perfect from what I can see... With new wings and possibly new harizontal tails, it may be prettier, yet.

Jack
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Old May 31, 2007, 11:51 AM
Registered User
Lexington, KY
Joined Jul 2003
163 Posts
Dragonfly Strong

Hi Jack:

I would take this up with Bob Breaux at SoaringUSA. This is classified as a F3J model that is supposed to handle 2 man tows, and the claim is that it can handle full pedal launches. If there is a problem with sloppy workmanship I think Valenta should address it.

I am pretty careful during launch and make sure I don't launch like a moldie. I t sure looks good and flies well, and I am disappointed to hear of your troubles with this sailplane.
Regards
AJ
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Old May 31, 2007, 03:49 PM
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mike5656's Avatar
san antonio texas
Joined Oct 2004
66 Posts
hi jack sorry to hear about the wing joints. i have around 100 flights on both of mine. both with histart and full power winches. i have stalled one winch on the launch of the dragonfly. (smaller winch). but i will keep an eye on the wing joints. thanks for the info. it's one fine sailplane.
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Old May 31, 2007, 08:39 PM
Bro
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Southern California
Joined Feb 2003
1,938 Posts
Dragonfly Strong

Howdy;
well, with many of these airframes out there, it is surprising to hear of "poor wing quality" on the model. I do not doubt it could be possible, but the one flying in our club takes a good hard launch, and flys extremely well. I have not seen many built up airframes that take abuse well though. I do think the wingtips are not as good as I personally like, but, the fit and finish on these models is 1st class for what the cost is... IMHO...

This being the first I have heard of this situation, I sure would like some pictures, and data to pass on to Valenta, instead of bashing an otherwise good airframe that all others seem to enjoy, and fly well.

Happy Landings! (soft)

Bob
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Old May 31, 2007, 09:02 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,786 Posts
Sorry if I offended anyone, but the truth of it is the truth of it. I don't consider that bashing. Bob is correct, in that for the price it's a good model. However, rather than call Bob and scream, I repaired it and continue to fly it. I'll be flying it Saturday at New Waverly. So, what I'm saying is, it isn't a moldie, and it's not up to par with something I hand built. If that's bashing to you, I'm sorry.

By the way, Bob gives very good service and if I had screamed... I'm sure he'd have made it right. It's a $600- ARF, though and I would have a little trouble with my concense if I screamed over this. It was just a heads up, with some pointed questions to be answered. I answered truthfully, from my point of view, and stand by my answers.

Jack
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Old Jun 01, 2007, 03:46 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
6,940 Posts
Thanks guys, I think that was a fair and honest debate (that's what these forums are all about, no?). As Jack says, it's more of a heads-up, no machine will last forever, it's good to know where to keep an eye on..........

Chris

who is still very happy that he bought one, and is seriously thinking about another one to have as a pure glider
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Old Jun 01, 2007, 09:30 AM
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Joined Apr 2006
243 Posts
I figured I would wade in as the thread starter.
I have been practicing with mine pretty extensively. I have a talking timer and essentially a practice session is 3 timed flights to get an average for the day, then set the timer for one minute beyond the average time and attempt points landings until the radio is out of battery.

How many flights have I made? No bloody idea. A bunch would be a fair guess.
Have I landed it hard? Oh yeah. Hard enough to pop the reciever out of the velcro. I put a skeg on the front that I reinforced with a lay up of CF to cushion it and I have been grinding that thing to a pulp.

Bottom line (and not to disagree with Jack because I respect him, his opinion and flying ability) I have thus far had no issues.

I have had two small things to contend with that will happen regardless of the model. I was flying in the desert and popped a few holes in the covering landing in rough areas and I hyper extended the rudder once so that the trim that seals the rudder hinge got stuck and I had to make a few snips to get the rudder to re-seat.

I just picked up an Ava so I will be flying that as well as my Dragonfly.

I feel it is still the best and least expensive way to take the step in a competition worthy full house glider that is currently available.

And yes the tips do suck.

I think this winter I will make some tiplets but for now I just glue the little suckers back on and hook it back up to the winch.

Tom
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Old Jun 01, 2007, 09:43 AM
Registered User
Lexington, KY
Joined Jul 2003
163 Posts
dragonfly strong

I agree with the Bob that there have been no reports of failures (unlike the BOT ARF old by Tower Hobbies) prior to Jack's experience, but nevertheless still something that should be brought to his attention if one does occur. I have launched it pretty hard on occasion with no problem, although I tend to tap it up most of the time especially with a good head-wind. I love this model and prefer to fly it over my Escape. So far no structural problem is apparent. Just my $0.02.
AJ
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Old Jun 01, 2007, 10:50 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
6,940 Posts
Well, I'm very happy to read these last two posts, seeing as I have JUST ordered my second Dragonfly airframe, this time a pure glider fuse .!!

Tom, did you use a proprietary, ready-made skeg, or did you just make something up yourself? Any details perhaps?

I actually got my kits at a discount because the *** tips had come off on their way to the dealer. I am thinking of maybe some form of "tape-on-each-time-you-fly" system, to simplify the transportation of the wings. I was thinking of small dowels to locate them, and using some sort of non-gunky tape such as electrical insulation tape. Small magnets also could work, but I'm worried about the weight so far out on the wings.

AJ: where exactly do you tape it up?

Chris

who is a happy puppy
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Old Jun 01, 2007, 11:12 AM
Registered User
Lexington, KY
Joined Jul 2003
163 Posts
dragongly S tips

Chris.

I accidentally knocked one loose when i first got it, so I removed both and made sure there was no monokote overlapping into the root section of the tip (i.e. in the glue joint). I then laterally balanced the model using a little piece of lead sheet. After determining the appropriate amount of lead needed to balance the wings, I then carved a slot into the tip section of the lighter wing and slid the weight in and CA'd it in place . I then glued using 20 min epoxy holding the tips in place with some blue masking tape. After it set I removed the masking tape and sealed it with clear wing tape. I have semi-cartwheeled it on the tips on a very windy day and they have held fine. The idea with the dowels should work fine. Perhaps you can use some CF rods a dowels and then tape in place.
Cheers
AJ
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Old Jun 01, 2007, 01:37 PM
Registered User
Joined Apr 2006
243 Posts
Skeg's

I use the SD-6 tape on teeth

http://www.superskeg.com/

I took carbon tow and made a lay up that is slightly wider and longer then the skeg itself. The idea was much like a suit of armor it would spread the shock of the landing out over a wider area of the fuse to keep from working one area too hard.
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