Last of the Diabolo S: #14

[EatMorePizza]

Stunning Heli my friend.

[Clarence Creer]

Absolutely beautiful. Looking forward to seeing it in person.

[tgiencke]

Originally Posted by EatMorePizza

Stunning Heli my friend.

Originally Posted by Clarence Creer

Absolutely beautiful. Looking forward to seeing it in person.

Thank you for the kind words. Praise goes to Gerd and his team. The DS #14 is not a “hanger queen”, in fact pretty much a working thoroughbred with a rookie jockey. So the gear lube is being flung, and the Speed Gods are getting their (insect) sacrifices.

I thought I would post some pictures of the screens from the Jeti DC-16 radio to give an overview of the telemetry system installed on DS #14. The first screen is mainly for recovery of the DC-16 if it gets lost or stolen. I do this with all my electronics when able.



This is the main screen that I’m flying with while training. IRCHA Speed Cup has a 4 minute time limit, hence the timer (not for battery discharge). mAh consumed is for monitoring battery discharged. I have to fly between 5m and 35m above ground altitude during the timed run so this is for glancing at. (I just installed the sensor so need to test, if it doesn’t work because of pressure in the fuselage, I’ll use GPS altitude which isn’t as accurate.) I need to practice completing the ½ Cuban eight loop before reaching the pre-staging area (200m or two American football fields away), hence the distance reading. ESC (and LiPo) temperature are the power limiting factors. The small numbers are the min/max readings (in all large data fields). Speed is not included on the main page because that is being voiced by the Jeti radio when above a set speed.



BEC temperature is not critical, but I wouldn’t want it to fail either. LiPo temperature is critical so it is being monitored here.



Motor stator temperature is not critical with my low internal resistance motor. But it does affect the other two temperatures. The front inside ambient temperature sensor is in front of the ESC (pretty much as far forward as possible). The rear “ambient” temperature sensor is the MVario2 sensor, which is inside a static air-pressure vessel located on the forward part of the tail-boom. It is susceptible to self-heating, but it is better than nothing at sensing the air temperature as it flows out the tailboom.



The CVS16 monitors all 14 individual LiPo cells and reports the lowest one. The small minimum reading is the most important of the window. It is going to tell me if a cell went weak after a flight and I can take that battery out of the rotation. Instead of running a buffer/back-up LiPo for the Kosmik BEC, I am using a 50F capacitor buffer pack because it is lighter. It will allow me enough time to land immediately if the BEC fails. The BEC voltage is not given by the Kosmik, so I use receiver input voltage for BEC monitoring. Notice that receiver voltage is at the top of all windows. The transmitter power is just interesting information to use to figure out how long until my transmitter battery is going to die.



Motor amps and head speed are more just interesting information. The useful information is the maximum throttle percentage. This is going to tell me if a flight pack is going weak as a whole. If I set a head speed and fly in such a way that shouldn’t get close to 100% throttle; and it does then that flight pack needs to be investigated.



Oh the all-important speed. It is on page 7 because this information is usually voiced when high enough. Pressure altitude is needed to calculate density altitude, which affects performance. This is interesting information because I am a real (plane) pilot. The Variometer window is just interesting information. The audible variometer tone is going to be used to judge for slight climb/dive during the run if my sensor works inside the fuselage (soon to be tested).



If the MVario2 is of no flight dynamics use it is still going to be useful in cooling troubleshooting; for measuring inside fuselage pressure. This information is going to direct my cooling direction, either letting more air into the fuselage, or letting air escape the fuselage. The Kosmik BEC is more than capable of powering everything; so this is just interesting information. Lat. & Long. are only useful if I lose sight of the model and I need to do a blind auto (the Bavarian Demon 3SX will keep it level). The hope is to recover the model intact.



That is the most telemetry the Jeti can handle (32 items). If I need to add more temperature sensors I will need to temporally disconnect some other sensors. I couldn’t include the Jeti MGPS for course data and still have the MVario2; so I removed the MGPS. I still have the Power Box Systems doppler GPS-II.

All items are also being logged in the Jeti and can be displayed as an item value vs time (zoom-able) graph on the Jeti; and/or downloaded to a PC for analysis.

As always ask any questions you may have; and please comment.

Thank you.

[craigdieselmac]

That is an abundance of information!

[Raptorapture]

That my friend is one helluva setup!

I was thinking of some visual cues for remote assessment of orientation, just in case, especially the "turn" but had not dreamed of half your sensors. Great to hear how you are using them.

Will be interesting to hear how this evolves.

[tgiencke]

Originally Posted by craigdieselmac

That is an abundance of information!

Originally Posted by Raptorapture

Will be interesting to hear how this evolves.

Thanks. It is all from just a few sensors. In fact I could remove the MT-125 (LiPo temp) sensor and instead wire $3 temperature sensors into the JLog directly and get the same information. That is what I'm going to do over the winter.

For evolution, it is now thinking of different voice call outs that are triggered by the telemetry. Not alarms. Think of things that a coaching spotter would say. Like "Climb angle" when I'm climbing too fast at the beginning of the 1/2 Cuban 8. "Roll" at rolling altitude. "Begin" at the altitude of the top of the 1/2 loop. "Stage" at 200m away. "Trap" when I'm 100m away and have entered the timing area. Speed numbers when above a certain speed. "Woohoo that speed beat your best" when I do well. This is why I installed the MVario2 and I hope the static vessel works inside the fuselage. Also couching reminders to take care of the model like "time to bring it in, the ESC/LiPos are getting too hot", "time to regrease the gears", "check cell number X, it is getting weak", "check this flight pack, the throttle went to 100%", "land now" when the receiver voltage is being supplied by the capacitor pack. I want the Jeti call outs to improve my flying, and not just fancy alarms.

I use the free AT&T Natural Voices to make custom call outs, then use iTunes to convert the files to an appropriate .wav file for the Jeti.

I may have Justin record a bunch of call outs, so he can be my flying "couch". (hint hint :-) )

It's all well and good tinkering with the model. I still have to fly the darn thing. So please don't look for me to do well at the Speed Cup. My goal is just to do better than Justin's first year. ;-)

As always... Thanks

[tgiencke]

I took off the fuselage to work on some baffling so here is a picture of the (older version) R2 Prototyping 50F buffer circuit and MVario2 static vessel installation. If you look closely you can see the “static port” pin hole in the lower aft portion of the plastic tubing. There is another hole on the other side.



Here is the CVS16 installation. There is an extension going to the front battery balance lead. Between the CVS16 and MT125 temperature sensor, the front battery fits like a glove. I am impressed with all of the R2 Prototyping items.

[Justin Pucci]

Todd, I'd be happy to do voices for you and the Jeti!

The telemetry setup is truly impressive and the "more than fancy alarms" is something that I'm working on too. Jeti is definitely capable of it, so we just need to work through the programming details. The training potential in the speed world is significant once we harness the radio's full abilities.

...and trust me, you will definitely do better than I did last year! By the way, that's my personal goal too!

[tgiencke]

I was asked how I attached the (MT300) stator temperature probe on the Pyro motor; so I thought I would share the information with the group. The MT300 sensor is a simple thermistor that is epoxied to a stator wire using Omega OB-101 thermally conductive epoxy.



A little insight that I gained while doing 260+km/h runs without any fuselage venting; motor temperature is never an issue with a <10mOhm single/multiple wire winding. It doesn’t even come close. ESC (Kosmik FET) and LiPo temperatures are the limiting issues. I have to monitor ESC temperature when I am at idle up 2 (2000RPM) and practicing technique because even though the Kosmik is a freewheeling ESC there still is a lot of resistance while the FET are switching on/off. When I am at idle up 3 (2600RPM) the ESC temperature actually decreases because the FET is switching less (with my understanding of ESC operation). At idle up 3 I have to monitor LiPo temperatures because of the current draw. So actually if I was to install NACA ducts I would install them on the underside of the fuselage to cool the LiPos, and possibly add an aluminum heatsink to the bottom of the LiPos.

Oh, and by the way the variometer works great in the fuselage as an altitude sensor. It is just pretty useless as a temperature sensor.

[tgiencke]

The R2 Cap Pack paid for itself 90 times over today.

I have been practicing applying full collective in the ½ Cuban 8 loop to build centrifugal force. This caused a 12.1kW (16HP) power spike for a half a second. Then the run pulled 8.5kW (11.3HP) for 9 seconds. The result of all this power was the EC5 connector desoldered.

The previous day of flying this same connector’s solder cup had heated enough to melt the blue plastic. I had resoldered the EC5 with new components. This time the wire lead disconnected. (BTW motor temperature was a cool 83C and heat soaked to 105C after the run. The magnets are rated to 150C and wire to 300C.)

After the wire disconnected the electronics were running on the Cap Pack and the Jeti told me so. I completed my first EVER real life auto, just clearing the 5’ corn stalks to do a blind auto into some tall grass. The only “damage” was grass stains on the blades; which cleaned off to not leave any mark of the incident. Gerd and the Minicopter team make a strong fuselage.

All connectors are being replaced with PRC8 connectors.

[Wh1teAfr1can]

Originally Posted by tgiencke

The R2 Cap Pack paid for itself 90 times over today.

I have been practicing applying full collective in the ½ Cuban 8 loop to build centrifugal force. This caused a 12.1kW (16HP) power spike for a half a second. Then the run pulled 8.5kW (11.3HP) for 9 seconds. The result of all this power was the EC5 connector desoldered.

The previous day of flying this same connector’s solder cup had heated enough to melt the blue plastic. I had resoldered the EC5 with new components. This time the wire lead disconnected. (BTW motor temperature was a cool 83C and heat soaked to 105C after the run. The magnets are rated to 150C and wire to 300C.)

After the wire disconnected the electronics were running on the Cap Pack and the Jeti told me so. I completed my first EVER real life auto, just clearing the 5’ corn stalks to do a blind auto into some tall grass. The only “damage” was grass stains on the blades; which cleaned off to not leave any mark of the incident. Gerd and the Minicopter team make a strong fuselage.

All connectors are being replaced with PRC8 connectors.

Yeah EC5 are not enough contact area for a speed machine. wait til you have 460 amp spikes and 220 continuous in a pass.

[Raptorapture]

Good save! I'm now wondering if 6.5mm Castles are enough...

[smsodhi]

Serious power.

Out of interest, was it the connector that plugs into the ESC or one of the battery connectors on the harness that failed?

I have always felt there is more pressure on the ESC to ESC connector on the harness and have desoldered an EC5 here also, twice. I use EC5 on the batteries but use a CC6.5 on the ESC to ESC in the Diabolo and more recently put a 8mm RC proplus in my Goblin to accommodate BEC wires also.

[helicraze]

Castle polarized are great i upgraded before the above happened lol

[tgiencke]

Originally Posted by smsodhi

Out of interest, was it the connector that plugs into the ESC or one of the battery connectors on the harness that failed?

Originally Posted by Raptorapture

Good save! I'm now wondering if 6.5mm Castles are enough...

The connector that has desoldered is the negative male pin of the rear battery connector. By looking at the melting of the blue shroud, the heat is being generated at the male pin cage and flowing to the solder cup. I am not 100% confident in the solder connection the first time this shroud melted; but I am 100% confident in the solder connection the second time it melted & desoldered. This coincides with electron flow theory.

I am using the DS14 as a testbed for heat management. The forward free-air temperature is rising to 60°C (140°F). Which is hot, but not hot enough to cause failure. The LiPos will heat soak to this temperature, but it isn't enough to cause them harm. The ESC heat sink becomes almost useless in this environment, but so long as the FET temperature stays under 90°C (194°F) all is well in the world. But the margins are getting thin.

In full-size aviation electrical installation we have ratings for bundled wires and "in free-air" wires. The rest of the EC5 connectors could be described as being in free-air. The rear battery connector is laying against the forward LiPo; which is generating heat. The combination of current generated heat, LiPo heat, and free-air heat is what brought the solder cup to the melting point. I have found the failure point of EC5 connectors so choose to not include them in the testing any more.

I have 6AWG wire in-hand; that is the only reason I am going to such a large connector. 6mm bullet type connectors should give enough safety margin for typical high power use, especially if it is in free-air.

[tgiencke]

Well here is the massively overbuilt series adapter with PRC8 connectors and 6AWG wire. I always wanted to remake my series adapter into this two connector type.





Big wire requires big terminals. I am interested in how the new wire is going to affect the internal ambient temperature.

[robbarnes1098]

Im using these on mine with superb results , the solder Im using also has a 4% silver content .

http://www.modelhelicopters.co.uk/te...p8-connectors/

[tgiencke]

(The following is an "editorial" comment.)

I greatly dislike proprietary electrical connectors of any type. In every instance they make the user's experience possibly a negative one. Each industry should find a majority decision and then conform to that decision for the good of the user experience.

In the U.S. for high power RC connectors it is my opinion that the majority decision is the E-flite EC5. I am not stating that they are the best at anything; but that they are the majority decision, and commonly available. I will still use them in the 12S Goblin Speed because the peak wattage is less, and ample airflow to keep the connectors cool.

In the DS14 I have found their failure point so I am forced to use something different. I am not interested in testing connectors or wire size in the DS14, so chose to massively over-specify the connector and wire. (I also had the wire in-hand, so it eased the decision). And I can remove ballast to compensate for the increased weight.

The main issue with using a non-conforming connector is the ramifications to the user snowballs with how many times the connector is used. For example, I have 6S (EC5) and 7S (PRC8) LiPos that I parallel charge two to six LiPos at a time. I could change everything over to PRC8 connectors at great cost. But it is less expensive (and simpler) to buy another Revolectrix MPA paralleling board for the PRC8 connectors.

They are many great connectors on the market. You and your flying companions choose one and stick to it for the greatest user experience.

[Martinshelis]

Originally Posted by tgiencke

I feel privileged to own the model.

Any you should! Glad you were able to save your heli when the connector desoldered itself. If you every get a chance please take and post a video of it. Thanks for taking the time to show this beautiful beautiful bird!

[tgiencke]

Originally Posted by sm1nts2escape

Any you should! Glad you were able to save your heli when the connector desoldered itself. If you every get a chance please take and post a video of it. Thanks for taking the time to show this beautiful beautiful bird!

Thank you for your comments. I think I am a little due for an update on what has been going on with the DS#14 on the way to IRCHA Speed Cup. As my skills have improved I have been pushing the DS harder. On Saturday, July 18th I caused the Kosmik to go into over-current shut-down at a recorded 290 amps. I was forced to auto into a field of 7’ tall corn as softly as possible. At the time I was confident that the model would be ok. I was most concerned of how I was going to locate the model because it was >100m away from me.

The Power Box doppler GPS and Jeti radio came to the rescue. I paged the Jeti to the latitude / longitude page and wrote down the last known coordinates of the model. Went home and got my old Garmin handheld GPS and made a waypoint. I used the Garmin to get to the waypoint; but the model wasn’t there even though I had 12’ GPS accuracy on the Garmin. But I was close enough to the model that the Jeti radio could receive the receiver telemetry through all of the corn; and the Jeti had an updated set of coordinates. This time the Garmin brought me close enough to be able to hear the servos. The honest truth is if I didn’t have the Power Box GPS and Jeti telemetry, I would have had to walk each row of corn in that field; the corn was so thick that I had to stand over the model before I could see it.

Ok what was the damage? The BeastX X713S main blades were destroyed. The Rail R-96 tail blades were fine but notched at the root when they folded in the grips. The right cyclic SAB servo arm was broken, and I stripped the sacrificial nylon gear in the Futaba BLS175SV elevator servo. And that is it. After cleaning off the mud from the fuselage, there isn’t even a scratch on it!

I’ll say it again. Gerd and his team make a strong fuselage and model. At this point it must sound like I’m a “fan-boy”. But really it is through appreciation of the design & manufacturing that has gone into this model. It not only is very fast, but very strong.

I bought a new set of X713S & R-96 blades, and Futaba replaced the stripped gear for free! I bought a couple extras to have spares, and to support such great service.

So in the downtime I have been continuing practicing with my Goblin Speed. I have installed a single NACA duct into the nose of the DS#14 after doing testing that showed that I needed the opening for when the outside ambient temperature is >90F. I modified the stock tailfin into a single support. And I am replacing the Stock Kosmik Cool fan with a higher performance 50mm fan. I will post pictures soon.

I am on vacation through IRCHA so have enough time to finish putting the DS#14 back together. Removing and installing the fuselage really gets easy after you have done it a few times. I will be practicing with the DS#14 this weekend, but only over a cut-grass field so if I need to auto I am able to without damage.

Unless Kontronik releases a Kosmik 300+ ESC; I will be replacing the Kosmik with an YGE 320A 16S ESC & SM Modellbau Unisens E 280A telemetry sensor over the winter. This is only due to the Kosmik not having enough current capacity for my needs.

At IRCHA I will be taking a lot of video with a Nikon camera; some of which will be of me flying the DS14. Being that this is my first race, I don’t plan on being competitive; just trying to do my best.