Extremeflight 91" Yak 54 EXP Build Thread
This is by far the largest model I will have built, and I just made all of the orders in the last two days, so they should begin coming in. When all is here, (or when I freak out from waiting) I will drive to Extremeflight in Cumming GA and pick up my airframe.
Here are my choices for this build.
1. Airframe (Obviously) Extremeflight. I love EF and they're local. The carbon fiber in the structure makes a difference to me. Worth the minimal difference in price.
- Others I compared - 3DHS (No Yak 54, Not Local.) Goldwing etc. (Generalhobby.com) Cost the same or more than EF with shipping. No CF. Pilot RC (From Chief) - Overpriced in my opinion, apart from warranty, no clue why so expensive. Krill (I'd want an oversprayer scheme, but that's crazy kind of money for an airframe.)
2. Motor choice ended up being Turnigy Rotomax 50cc. - It was very very close to being a Hacker Q80-8M and will be so if I have motor issues.
3. ESC Turnigy DLUX 160HV - Gonna try Turnigy for ESC. Have not gotten a bad one yet.
4. Receiver - OrangeRX 8 ch DSMX + 2 DSMX Satellites.
5. AUX Power - Turnigy voltage regulator, 10 amp, + two x 2 cell batteries.
6. Servos - Rudder servo will be a Turnigy 40KG digital titanium gear servo. It's big at 175 grams, but only going this route on the rudder. 4 x Turnigy Digital 55 gram servos on the rest with 25KG of torque.
7. Batteries - 6S 20C 5000 packs. (I got 4.) I think 20C will be ok in 12 cell setup, so no need for crazy expensive mad C rating.
Additional Items. (Options and not sure how I will use em yet.)
*** GYRO / Autopilot - Got two. One Copilot II, and one Accelerometer based Arkbird setup.
* Ideally I am looking for workable and easy auto-level, 3D assisting option, as well as a return to home capability.
* Features I can't wait to try out:
- Copilot II - Hard Deck Module... (Fake impossible to cross floor of 50 feet up.) Bail out. (Instant restablize to level flight.) Want to see how to make GPS work for RTH on Copilot. (Think this is currently impossible.)
- Arkbird - 3D Hover Assist. (Spank out some GOD MODE 3D with a plane big as my car.... LOL Want to see how and what this does for it.) Try to use bailout in a high speed blender... Buzzzzzzzzz....... Flick. LMAO!!!
*** Wireless Buddy Box. - Allows hook up of two radios. I plan one one x DSMX and one FlySky and comparing range. I like the idea of being able to teach folks with this plane, so depending on how well it all works out with autolevel, GPS RTH, and Altitude hold / Hard deck, I think I can make that happen.
*** Test Platforms and goodies. - I plan on using a couple of other models as test platforms prior to adding the complex stuff to the Big yak.
Nothing is really here yet, but will post more when the goodies get here.
Wish me luck!!!
That Sounds like a Nice Plane :ws: Gee, I thought my 80" W/S Bi Plane Was Big :D
Very very nice!
What amps are you anticipating? The 20c batteries are only rated for 100A (even if they are honestly rated), which seems a bit short compared to your other hardware.
Expecting about 90 to 100 amps.
If more, I plan to set my throttle limit to keep it reasonable and get some 25c batteries. (So WOT will be like 80% Throttle... Still plenty)
I just learned the math, and if my math is right, about 5000 watts, 100 amps and (LOL....) a whopping 3 min of flight time with 5000 mah.
That's at WOT though. I am usually lighter on the throttle, and tend to shoot for that 2:1 thrust to weight too.
That's just sick. Fly one floaty plane with 2 to 1 and you will be hopelessly hooked.
All parts are now on US soil. (Wooooot!)
Unusually fast for Hobbyking, actually scary fast. (about 4 days from checkout to on US soil. DEFINATELY not normal, but I'll take it :-) )
Making arrangements to pick up the airframe next week.
OMG! Many surprises!!!
1. The motor arrived. It's much smaller than I had expected, but still comes in something like a shoebox.
2. The Batteries are HUGE! I had no idea to expect them to be that large, but they are here.
3. The Rudder servo I got is also huge!
Looks like some of the packages will be another few days out though.
So far the Batteries, Motor, All Servos, Servo Extensions, Satellite extensions, and Receiver Batteries came in as well as my wattmeter.
Props, Receivers, Voltage Regulator and autopilot not yet here.
I think I will be pretty well set up soon to start on it.
Charged all four of the batteries last night and today.
They took just over 2 hours each to charge on a Thunder AC 6.
Any advice on a good wall plug charger (up to 6 cell) that won't break the bank?
Serious batteries need a serious charger. My icharger 4010 duo will charge eight 6s 5000mAh in about 20 minutes. But the icharger isnt cheap!..
In terms of watts of charging power for $ spent I've not seen anything better than this one: http://www.hobbyking.com/hobbyking/s...e_Charger.html
On that charger you are getting 9 watts of charge power for every 1$ you spend. For comparison, on the Accucel 6 that some claim to be best bang for buck you get 2 watts per $.
Hook it up to a parallel board and suitable PSU and you have some serious charging capability.
Still, that should be more than enough power.
I'm wondering why you went for such a vast servo on the rudder? It's far larger than Extreme flight recommend.
Just went for it. It was cheap, and seemed more than adequate. Figured I would be better off that way.
I know I have room for it, and I can go that route but yes! That thing is massive!
Hmmm, you will probably have to do a bit of wood chopping and beefing up to fit such a huge servo in, and 100g is a fair bit of extra weight to lug around for no benefit. I’m sure it can be made to work but personally I'd get a servo that was the recommended size.
I have a spare that is the recommended size also.
Just remember seeing larger planes right at that 100 inch span mark that take multiple servos for rudder and some funky setups.
I'm going to be 9 inches away from that mark, and it's a big wooden flat spot the servo goes into.
A few more parts arrived today.
The Props 26x12 and one so far came actually fully balanced. (I got three and I don't expect the other two to be so lucky, but the first one is with no changes.)
The Turnigy props are very well finished.
Another Boo Boo is that I didn't get a drilling jig. I will probably make one, or at least mark them and use one of my relative's drill press.
My wireless buddy box arrived too.
I can't wait for more to get here.
Still waiting on the Receivers and autopilot.
Got the airframe today! Got off early and raced up there before 2:00 pm to get it.
It is huge. The packing was better than anything I have seen before. 1/4 inch thick cardboard inside of a normal cardboard box.
The wings, stabs and canopy had Mylar bags and covers.
The wheels were smaller than I expected, but it was the most beautiful covering and design I have seen.
The carbon fiber spars in this one are over 1/8 inch thick too.
Eyeballing the rudder servo area, my big honkin' Turnigy just might fit with a file here and there.
I hope I can do this kit justice.
Got to test fit the parts and see the size today.
Me and son holding it up.
Daughter with it outside.
The cowl fits so perfectly and the quality is just shocking on this thing.
Looking good man! :)
Thanks! Also one more update.... The massive servo FITS WITHOUT MODIFICATION!!!
Actually like a glove. Drops right in. To use the recommended servo, you glue in a reinforcement servo holder.
I'm taking that and gluing it in anyway as extra reinforcement, but the servo actually fits like it was meant to be there.
That's an impressive looking model for sure! Good that the servo fits.
My two Hacker A60 motors are only about 2 1/3 inches in diameter, but they spin a 19X12 prop at near 7000 RPM. And only get slightly warm in doing so. It does look strange to see a 19 inch prop on a motor that is only 2 1/3 inches in diameter.
After running your motor with the prop, you'll also quickly learn that it is wise to do set up and testing of your model WITH THE PROP OFF! :D :D :censor: (If you try running that thing in your room with the pictures on the wall, you might find them all laying on the floor :D :D) Also, keep a close eye on how hot your motor is running. www.motocalc.com suggests that running this motor with a 26 inch prop and a 12S LiPo battery will result in a very hot running motor.
Compared to a gasoline engine, these multi-kilowatt motors are rather small in size, but, you'll discover it is not a good idea to get anywhere near that prop when the motor is powered up!
Yep. I will have to get a photo of the prop on the motor. (Gotta drill out the prop first)
Just doing the prelim work. (Hinges, horns, and landing gear.)
I might be hopelessly hooked on this size if it works out well.
Good news is that I don't even remotely want a bigger one. ;-)
Many e-pilots have learned that lesson the hard way - especially when using equipment that has a reputation for over estimating how many amps their gear can honestly handle.
I would highly recommend you prop so that everything - esc, battery and motor - is safely within limits at full throttle. if not you risk the entire model.
I had asked the folks at HK about the prop with a 12 cell and they say its fine.
Not saying I take that as 100% truth, but I'm ok with trying the 26x12.
I can shift batteries, props, etc even motor really. I opted out of the Hacker Q80-8m, so if anything happens with the Turnigy, I'm headed that way.
I got a wattmeter to try out on this one, so I will know before I fly.
As for that wattmeter, when you get to these size electric power systems, an alternate to those wattmeters is an AC AND DC clamp on ammeter. Note that most clamp on ammeters are AC only, not useful for our stuff.
If your in the USA, Sears has a Craftsman #82369 AC/DC clamp on ammeter that works very well. I keep mine in my flight box, so if anyone at the field has a question on how much current their power system is pulling, a quick test with this unit gives an immediate answer. No adapter cables required, just clamp the meter around ONE of the battery leads. Its DC current ranges are 0-40 and 0-400 Amps, that will cover any electric motor that we use in our electric airplanes.
(It also works to measure your auto's alternator output, how much current your starter pulls, even if any electronic stuff is still on in your car with the ignition turned off.)
Take a look:
My point was that IF you have too much amp draw - you cannot compensate for it by lowering the throttle end points on your tx.
It just doesnt work the way most people think it does.
Your esc will over heat MORE at part throttle than it does at full throttle. In some cases a LOT more.
If your power system is pulling too many amps, you will only make things worse - and more likely to fail - by backing off on the throttle.
I know thats counter intuitive, but thats how things work with our brushless toys :)
Someone just recently reported loosing an expensive EDF by doing just that. The esc fried and the entire model was lost on the maiden flight.
Check the amp draw on the bench at full throttle. IF its too hi, then either prop down or get a larger esc/motor/battery pack.
With Turnegy stuff I would suggest never going more than about 75% of the advertised specs - at the very most.
But thats just me :)
Another thing to keep in mind is that you're playing at a much higher scale than with the small stuff.
If you're over spec by 5% on a 200 watt setup thats only about 10 watts to worry about. Maybe your esc/battery/motor can handle an extra 10 watts of heating for several seconds in a 3D maneuver. By the time you land everything has cooled down and you think your fine.
On a 7000 watt setup, that same 5% over spec is now 350 watts of extra heating for the equipment to worry about. Thats not so easily handled.
Things tend to blow up a lot faster when playing with giant scale electrical systems if you're not very very careful.
I know it wont be a big loss if your Turnegy stuff blows up, but if they take the airframe with them, you will not be a happy camper.
When a hi powered esc goes up there are major flames.
Most people worry about batteries flaming up, but esc's can set fire to a model just as easily when your pushing huge watts.
I am speaking from experience with hi power setups and giant scale electrics. They are not nearly as forgiving as the small stuff.
Hi :ws: You might want to use a Anti Spark Resistor with 12 cells 44.4 volts, it will sound like a shotgun going off when you hook up the lipos to the esc, a 1 to 2 Ohm, 1/2 to 1 Watt Resistor Circuit hook up before the lipo to esc will allow the caps to charge up in the esc, preventing the huge electrical ark and loud noise :eek: :D, Just my 2 cents worth.
I just read the Turnigy Dlux 160A ESC specs, it comes with a Anti spark lead, How about that :D Thats a First :) anyway, the Info Here shows how it needs to be wired up.
Max Cont Current: 160A
Max Burst Current: 180A
Max RPM (2-pole): 200,000rpm
Size: 83 x 33 x 23mm
Motor Plug: Female 4mm bullet Connector
Battery Plug: Nil
Features: Spark Eliminator Lead with 2mm Plug
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