HK Specter 1800 - Page 3 - RC Groups
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Jul 29, 2012, 02:14 AM
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The Specter flies hands' off quite well. It won't pull itself out of a 45 degree bank but it levels out if you get it close. It also holds a turn with just a little rudder. I keep it trimmed so that hands' off is just a tad nose down so I also hold a little up when I'm trying to work lift.

$17.00 compared to $13.00 doesn't really even register with me. I might switch to something more expensive if I run into a short lifespan but it seems to me that QC is the big issue with Chinese electronics. If it works out of the box? It works well. If there's something wrong? It won't work out of the box.
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Jul 30, 2012, 01:36 PM
Registered User

Evolving color scheme.

I wanted a little better visibility on landing approaches so I made it a little louder. It looks very nice in the air. Will this be the final evolution? I don't know.
Jul 30, 2012, 02:54 PM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar

Can you upload a shot of how the nose turned out where you ran the wires from the outrunner to avoid having them hit the spinning can inside the nose?

Thanks! Dale
Jul 30, 2012, 03:35 PM
Registered User
You got it, Dale. I just used a chunk of 1/32" ply and a little CA to keep the wires out of the way. BTW. The new color scheme really, really, helps out my old eyes.
Jul 30, 2012, 04:30 PM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
Really clean and nice looking, very cool. I had thought you previously said you would need to run the wires outside of the fuse. I am apparently mixing up threads. That's what happens when I spend a full evening reading through some of the material online here!

I found the other thread here:
In that HK Riot plane using a 36 sized motor they had to run the wires outside. No doubt they could have stayed inside if they used a 28mm motor as you have. Honestly it seems like a 28mm motor would do the job nicely anyway!

Some people are putting together insane power combos... like shown in this video:
Speedfire F5B, by Ming (5 min 30 sec)
Jul 30, 2012, 04:43 PM
Registered User
Heh! I'm pretty sure that that kind of power would fold the wings on the Specter! I'm a little leery about full power aerobatics as it is. Assuming that my motor doesn't fry for no good reason I think I'll pick up another just in case I get another glider in the 2 meter class. I'll decide for sure when my watt meter shows up and I can check the draw for myself but I have seen claims that it will handle a 12X6 for as long as a glider needs power and an 11X6 is almost certainly an option. If so I think it would be fine up to around 1500grams.
Jul 31, 2012, 04:41 PM
Registered User

A few more data points.

I'm stillllll waaaaaaaiting for my watt meter but I decided to do some test runs with the motor. With the 9.5X8 prop I use about .17 volts with a 15 second motor run. I don't know if I've actually ever run it that long in the air but I figure it's a safe number to use. 6-8 climbs should still give me plenty of power to spend 15 minutes in cumulative gliding time and still have enough battery left to abort a landing and go around. About the only time that scenario would play out is just sport flying at dawn or dusk with no lift.

I forgot my watch today so I'm just guesstimating that my best flight was around 30 minutes after a single 12 second climb. The battery was at 11.9 volts when I came down! I figure about .13 volts per 10 minutes of flying? I don't really make many control inputs when I'm locked into a thermal. I just establish my bank, breathe back on the elevator, and maintain my turns with an occasional blip of rudder.

I have also noticed that my ESC runs cooler after painting the canopy orange. It wouldn't get too hot before but it was definitely warmer with the black canopy.
Jul 31, 2012, 05:51 PM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
Wow, you really are getting some wonderful flights in. My best with the eGabby is about 30 minutes but with a total of 4 minutes engine time. At perhaps 20-30 seconds each climb that means I had 10 or so climbs. I have not been climbing full power, but more 2/3rds as the near vertical climbs take time to adjust to.

You have an all up weight of 680 grams (according to a previous post) with 1.8m wide wings. I have an all up weight of 1125 grams with 2.0 m wings. You have a much lower wing loading and floating abilities. I can cover more ground, but then again I can only see so far with a 2m plane!
Jul 31, 2012, 06:39 PM
Registered User
Did I goof? The advertised weight is 680grams and mine is 780. That gives me a wing loading of 9.1 oz. per square foot. It floats when I pull a little back stick but flies fast and penetrates too when I want it. I've even got my aileron differential dialed in so it makes nice, axial, rolls.

I'm afraid that my field is a bit unfair. It has a 6 lane freeway a couple-hundred yards to the east and great big parking lots at both ends. I won't fly over the freeway but, if the wind is a bit from the east, the lift blows to me. If the wind is more from the north or south I can catch big stable thermals from the parking lots. If the wind is from due west I fly my Extra because I would have to fly behind trees to find lift.

Today was perfect with about 3mph of wind from the northeast and I was able to launch right into stable thermals on all but one flight. It's rather funny that after spending years roaming the countryside looking for good soaring sites I've found perhaps the best yet here in the suburbs. I usually even walk to the field with the plane in its box and using a fabric shopping bag as a tote.

I must admit that I get some funny looks while walking along the road but I've also raised some interest. I would really enjoy finding a couple other local fliers to get an informal club going. I don't have any takers yet but a few have asked for websites and looked pretty interested when I told them they could get a heck of a glider for less than $250.00.
Aug 03, 2012, 01:16 AM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
FYI I went ahead and ordered one too. I'll start building within days of arrival and will upload pics to share. I went with a different motor setup than you did, so we'll see how it goes. I don't think I need nearly as much power as you have, this is going to be a floater, not a racer.

Im going to use this motor:
Turnigy Aerodrive SK3 - 2830-1130kv Brushless Outrunner Motor
With this spinner:
Folding Propeller Assembly 10x6 (Alloy/Hub Spinner)

The motor is a little less powerful than yours, so I downsized the prop pitch just a bit. I'm also going with a 30A esc and MG servos. I'll be less weight on the engine and ESC, but gain a few grams on the servos. I appreciate your pictures as I ponder the install.

As an experiment I'm also going to use primarily HK parts. Just to play around. It'll be fun to compare how the HK stuff works for me compared to the Hitec things I'm using in my more expesive but more demanding 3D planes.
Last edited by SoarWest; Aug 03, 2012 at 02:56 AM.
Aug 03, 2012, 02:19 AM
Registered User
Excellent! I sure hope you like yours as much as I like mine. You might have to use a smaller prop than I do but I would think that the climb will be more than adequate. I ended up placing my receiver behind the servos and there's some extra room forward so balance shouldn't be hard to get right. I'll recheck my CG and post it.

The only reasons I went with the KDA are because I wanted a much more than adequate climb and was thinking of trying 2 cells with a much bigger prop. I haven't seen any need to go with the smaller battery. In fact, I'm going to pick up a couple bigger batteries so I can get longer flights when there's enough lift to carry them.

Lord knows there are plenty of horror stories about HK and Chinese products in general but I've had pretty good luck so far. It seems to me that QC is the big issue while design is fairly good (Usually their designs are flat-out stolen from other manufacturers.). The danger is that they ship a certain amount of defective parts but , if you get good ones, they work quite well. It's probably a good idea to check solder joints, screws, and glue joints to try and weed out anything that slipped through but I do that with just about any mechanical or electronic device.

Did I mention how I fit the HXT900 servos in the fuse? I cut out the front of the servo tray to slide them forward to where the fuse is a touch deeper and then ground off the outside corners of the servos with a sanding wheel. Then I just shimmed them and glued them in place. With the cheap servos, and figuring I won't be removing them unless they fail, I figure I can cut them out in pieces if I have to. I'll get a pic of the servos when I have light tomorrow.

Let me know if I can be of any help. There were a few spots where I had to sit and scratch my head a bit but this wasn't meant as a true build log so I didn't try to report every single one of them. There wasn't anything too traumatic. Just some places where the very minimal instruction sheet didn't help and a little work with the Dremel.
Aug 03, 2012, 02:54 AM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
I added additional info to the post 2 above, so that the build details would be together. Sorry for not including prop and ESC info earlier.
Aug 03, 2012, 10:36 AM
Registered User

Servo installation.

Here are the pics on my servo installation. As you can see; they just barely fit vertically. If your servos are deeper you may have to scrap the tray entirely and move them forward a bit more or, in the worst possible case, mount them on their sides.

Some other things in no particular order:

Looking back through the thread I noticed that I forgot to mention the pushrods. Mine took a little work to get working. I ended up just using a fine cutting bit on the Dremel to contour the exits and then mounted the control horns in such a way that they pull away from the fuse. I also lubricated them with a little Vaseline. It's also important to support the servo end of said pushrods. I just used a small block of foam shoved back into the boom and some scrap wood which I, very messily, glued to the rear of the tray.

After realizing that the front of the wing saddle provides the strength I elected to use music wire for the front wing posts. This should provide all the strength I need and provides for a little fine adjustment. I also added some 1/32" ply for the wing bolts. I didn't like the supplied nylon bolts and, since I don't think I've ever had nylon bolts save a wing, replaced them with steel bolts. I wasn't happy with the way the back of the wing saddle fit so I cut a 1/16" notch in the trailing edge. I also hardened the entire area with CA.

That's about all I can think of at the moment. I'll try to add details as I remember them.
Aug 03, 2012, 06:57 PM
JimNM's Avatar
Re: servos....

I used TP 9 gram servos and laid the flat in the cut outs. A dab of glue at the corners keeps them in place.. I shortened the arms a bit, using the third hole from the center. I hqd one go bad after the second maiden... It was used in another plane with uncertain history. I should have used new servos in the first place.
Aug 03, 2012, 06:58 PM
JimNM's Avatar
I glued my wings together and have made a doubler like Pete did, for the hold down bolts.

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