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Old Jun 14, 2011, 06:59 PM
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Quote:
Originally Posted by rclab1 View Post
Just asking, :-) but on the EspritModels website, it say's the plane is very much fully built?

just add servos and RC gear?

how true is this?
Post #40
No! Heck no! This was one of the most challenging builds we've ever done, we had two of us on it basically 5 days straight.

This RCG thread was our only saving grace, and even still we did stupid things like glue the tail feathers on instead of slipping them on.

David from Esprit tried to help me, and was very generous with his time. Despite all this, the manufacturer assumes you've built a few before, and nothing is spelled out in the instructions.

In other words, this is _not_ like building a regular ARF, at all.

I'm not trying to discourage you from buying the airplane, it's well worth the effort and you have already found the best place for help.

.. and it flies great!

Best,

- Eli
http://rcflyers.mirafiori.com
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Old Jun 29, 2011, 09:01 AM
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JoseLG's Avatar
Jerez Frontera (Spain)
Joined Nov 2004
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Sad news

Well.

Last saturday I was flying my Grafas and Lost the sight on it. When we see it again it was at 10 meters from the earth,and it hit hard. Both wingtips was broken,the carbon leading edge was delaminated and a lot of ribs was missing/broken.The Tip rib of the central panel was loose with the joiner attached (right side). And the fuse broke at the trailing edge of the wing. I used nylon bolts for fixing the wing instead of the steel supplied with the kit.

I`m going to rebuilt it, but I don`t know what to to do with the carbon leading edge (reglue the delaminations or replace it).

Probably I`ll order a new one, but this time the uncovered one.

Good winds.

José L.G.

P.S.: If I can I`ll post the grafic of the last flight, where you see the grade of descend.
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Old Jun 29, 2011, 02:03 PM
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Aw, Jose, you too? My condolences

Last Saturday, I lost my Grafas as well, apparently due to an electronics problem.

I had been up for about 45 minutes when the radio went into failsafe - what was designed to be a gentle left turn was not so gentle. It ended up going down in an AT&T yard, and scaring the heck out of two Bell guys. They were really nice about returning the ship.

The wing took some damage, as well as the fuselage, but we think this _may_ be fixable.

Better yet, we got video :-D

Grafas Flight, 6/25/2011 (4 min 19 sec)


The spiraling decent is quite hair-raising.

We are scrambling to fix the Grafas in time for my trip to Crater Lake in a few weeks, and just to be safe I put a Cularis on my credit card. I shipped all of my radio gear off to Horizon for inspection, let's hope they find something!

Cheers,

- Eli
http://rcflyers.mirafiori.com
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Old Jun 29, 2011, 05:01 PM
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Athens, Greece
Joined Apr 2010
454 Posts
Guys, whats going on?

Why are these beautiful birds coming down like this?

I have been lucky with dozens and dozens of flights so far.

Isaac could you measure what was left in the battery after the plane came down?

Do you tap power off the motor battery for the Rx or is there a separate battery on board?

mike
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Old Jun 30, 2011, 04:31 PM
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Hastings, Hawkes Bay, New Zealand (Aotearoa)
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If your Rx can do it, set failsafe to full crow brakes, that way it will not pick up so much speed.

Heather
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Old Jun 30, 2011, 07:37 PM
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Guys stop killing models, if you do not like them send them back to us.

Video was crazy, model hit the car, you are very lucky.

Zb
Esprit model
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Old Jul 25, 2011, 08:00 PM
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After much head scratching, I think we know why my crash occurred. BEC overload.
I was using the recommended setup, that being a Castle ICE 100 and the recommended Hitec digital servos.

The ICE has a 5A BEC in it. I've spoken to techs at Hitec, and also at Horizon Hobby's Support department, and they all say that six digital servos on a 5A BEC is not recommended, and could certainly cause low voltage conditions. Horizon inspected my radio equipment and gave it a clean bill of health.

Moral of the story - Either put analog servos in the thing, or a seperate RX pack/BEC. The recommended setup on Esprit's website probably works for a lot of folks, but the manufacturers of the equipment recommend otherwise.

At least we figured it out. I hate unexplained issues!

- Eli
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Old Jul 26, 2011, 08:02 AM
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Quote:
Originally Posted by isaac509 View Post
After much head scratching, I think we know why my crash occurred. BEC overload.
I was using the recommended setup, that being a Castle ICE 100 and the recommended Hitec digital servos.

The ICE has a 5A BEC in it. I've spoken to techs at Hitec, and also at Horizon Hobby's Support department, and they all say that six digital servos on a 5A BEC is not recommended, and could certainly cause low voltage conditions. Horizon inspected my radio equipment and gave it a clean bill of health.

Moral of the story - Either put analog servos in the thing, or a seperate RX pack/BEC. The recommended setup on Esprit's website probably works for a lot of folks, but the manufacturers of the equipment recommend otherwise.

At least we figured it out. I hate unexplained issues!

- Eli
You are kind of mistaken. If the Switching BEC is good for 60 Size 3D model it must be definitely good for a Sailplane. Your load on flying surfaces is not even close to its limitations. At full deflection in my eBandit 5000W, 18 lbs., 69” Jet with full load of digital servos, current NEVER went above 2.5A.

It’s definitely equipment failure but I would never blame it on Esprit’s recommendation. Did you use DSM2 or DSMX system? Send ESC to Castle for check up.
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Old Jul 26, 2011, 01:44 PM
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I spent a bunch of time talking to Hitec, and gave them the following list:

(4) HS-A5076HB servo (ailerons, flaps)
(1) HS-A5076HB servo (elevator)
(1) HS-85BB servo (rudder)
Castle ICE 100

They said that this setup was 'marginal at best' and that they would absolutely recommend a seperate BEC of 7A or above. He specifically recommended the CC/BEC, a product I've used with success many times.

When I talked to Larry at the Horizon Service department, he commented that he would always recommend a seperate BEC when using that many digitals. That sentiment was repeated over and over as I discussed this with different vendors. He gave my 9303 a clean bill of health, as noted previously.

I measured the current draw of one of the flap servos, and it was up around 800ma. WhenI put a current meter on the aircraft and started moving everything around, I was seeing numbers higher than 5A. I think that is a very meaningful measurement.

I'm not looking to 'blame' anybody. I noted in my post that your recommended setup obviously works well for a lot of people - You've sold more than one of these things, and obviously it's not an across the boards issue.

May I suggest that you guys go grab a current meter, hook it up to your shop Grafas and see what it's RX/servo setup is drawing? Blindly defensive posts don't hold much meaning for me, whereas solid science speaks for itself.

Thanks,

- Eli
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Old Jul 26, 2011, 02:05 PM
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Santa Rosa CA
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Quote:
Originally Posted by isaac509 View Post
I
May I suggest that you guys go grab a current meter, hook it up to your shop Grafas and see what it's RX/servo setup is drawing? Blindly defensive posts don't hold much meaning for me, whereas solid science speaks for itself.

Thanks,

- Eli
+1 I'd like to see those numbers as well.
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Old Jul 26, 2011, 06:28 PM
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There is no point of arguing. I would trace it to defective Radio, ESC, bad servo or bad linkage. I have seen my share of models going down for no apparent reason. It used to happen to warbirds all the time due to servo in mechanical retract, you bent the strut and gear gets stack and drains the Rx battery.

Just think about it, if you pull 5A for one hour, you need more than 6.6V 5000mAh Receiver battery.
And I bet you receiver will not sustain 5A continues current without overheating
.

I only wish you the best, I hate when there is no reason for crash.

Servo cannot and will not pull 0.8A without load. There must have been something wrong. You NEVER ever use all surfaces with full deflection on the sailplane at the same time. Ask 3D guys.

Here you go with VIDEOS:

Pulsar 4E
http://www.espritmodel.com/index.asp...D&ProdID=13774
(1) Neu 1509/1Y 6.7:1
(1) CC Phoenix ICE Lite 100SB ESC
(1) EM3300 4S battery
(4) HS-5125MG servo (flaps, ailerons)
(2) HS-A5076HB servo (elevator, rudder)

DH.100 Vampire EDF90
http://www.espritmodel.com/index.asp...D&ProdID=12225
(1) EDF Tam Jet TJ90 Fan
(1) Neu 1415/1.5Y
(2) EM3700 8S battery (4S + 4S)
(1) CC Phoenix ICE 100SB ESC
(3) HS-5085MG (ailerons, elevator)

Micro Flash Hotliner (ARF)
http://www.espritmodel.com/index.asp...D&ProdID=13819
(1) Hacker B40 10S 4.4:1
(1) CC Phoenix ICE Lite 75SB ESC
(1) EM3300 3S battery
(2) HS-5125MG servo (ailerons)
(1) HS-85BB servo (v-tail)
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Old Jul 26, 2011, 06:37 PM
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I have seen spikes up to 5A when I was moving all my surfaces. But you are taking about 4x servos per wing, 4x per fuselage, Total 12 Digital servos.

http://www.espritmodel.com/index.asp...=Custom&ID=110

HF Model Ventus 2cx:
With a span of 6 meters this 1:3 scale Ventus 2cx is a state of the art scale model. Fully hollow molded, high performance scale sailplane comes with high aspect ratio wings, pre-installed spoilers and landing gear. Nice on tow or slope, it can be also winched from a good TD winch. The cockpit comes finished with control columns, upholstered seats, and scale details such as instrument mushrooms complete with instruments. Ventus is very sleek, fully scale, high performance design, rock solid almost at any wind conditions. Average flying time is around 1-2 hours, depending on the weather conditions. FanAir 300 power unit comes with pre-installed FA-290 Outrunner motor and Aeronaut 18x9 3-blade folding propeller with custom spinner. We recommend EM6400 8S Li-Polymer battery pack. Expected 7-9 climbs per charge.

Flying time: Forever
Wingspan: 196/236" (5000/6000mm)
Length: 89" (2260mm)
Weight: 29.1 lbs. (13.25kg)
Power: FanAir 300, Jeti Spin 75 Opto ESC, EM-Pro 64000mAh 8S Li-poly battery
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Old Jul 27, 2011, 12:10 AM
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The Grafas is not fully reassembled, and once it is, I will evaluate it again as a built aircraft and report.

In my mind, the spirit of RCGroups.com is to share information, ideas, and help each other enjoy the hobby with success. These are complicated machines, and the ultimate "Multi Vendor Environment" in terms of potential engineering problems.

My takeaway from this experience is that I should engineer for current draw, measure my components on paper and in the real world, and finally, verify my setup before flying.
That's a lesson relearned, and vital to the hobby. Ultimately, the pilot and builder is responsible for the aircraft, no matter what.

I have a suspicion that additional testing on the Grafas setup we've been discussing might yield some surprising results, but I have to get the thing fully rebuilt and do a bunch more testing before I can speculate further.

Right when the concern came up regarding BEC power, I immediately thought of my HUGE Senior Telemaster and how low its current draw was on the RX/Servo side.
I immediately realized that the size or configuration of the Telemaster was irrelevant to the issue at hand. It’s a different airplane, and holding it up as a successful comparison was just confusing me.

It seems that a little of that sort of thinking has been going on in terms of rebuttal, and I suggest we let the matter drop until I can go gather some more data.

We’re all trying to prevent airplane crashes, which means we’re all inherently on the same team.

Best,

- Eli
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Old Jul 29, 2011, 12:26 AM
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Joined Jul 2011
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hi what is the difference between the ARF and ARC Grafas hachyu buy
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Old Jul 29, 2011, 08:21 AM
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JoseLG's Avatar
Jerez Frontera (Spain)
Joined Nov 2004
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Quote:
Originally Posted by aktan View Post
hi what is the difference between the ARF and ARC Grafas hachyu buy
Hi.

The ARF is covered in translucent colors. Just installing motor/ESC and radio (Rx and servos), make pushrods, etc.

The ARC (Almost Ready to Cover)is the same except the covering. I`ve just ordered one for replacement of the broken one. I`ll cover it in opaque colors to avoid dissorientation.

Good winds

José L.G.
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