HK Specter 1800 - Page 22 - RC Groups
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Oct 17, 2012, 07:19 PM
Registered User
Indeed. There are no substitutes for light weight or accrued stick time. I do, however, like a bit of size and weight for general flying. I think my next 3D will be something about the same dimensions but with a lighter structure. I also went with what are euphemistically billed as "12 gram" metal geared servos that actually weigh about 17 grams with the wires attached. I went with the extra durability on the Yak but, as I noted earlier, I plan on trying out the new "9gram" metal geared servos. I'm willing to add a little extra weight because, especially with large control surfaces, I have an incredible knack for blowing out plastic gears with the mere brush of a doorway.
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Oct 17, 2012, 07:36 PM
Earthbound Skyhound
StarHopper44's Avatar
175g?? That's a CRUSHER!!!!!

This is my newest play-purty - bending the scales at 55g without battery, 66.5g with!
Maidened 'er this past Sunday, & near everybody from our club's Jet Jockey to our Prez took a spin with 'er. Got 5 LiPos but ran out - first time I've had to re-charge from the car battery! *LOL*
It goes like a bat-outta-you-know-where, but just wait'll you throw the Hi-Rate switch & it's berzerker city!
Crashed it twice -- only damage a bent wheel pant & spinner popped off. There just ain't enough weight there to build any inertia!
OH if only my yard was a wee bit bigger!!!
Popcorn time! ::
Oct 20, 2012, 05:29 PM
Registered User
I had a great day flying both the Specter and the Yak yesterday. We were dodging light rain showers earlier so I didn't have to resort to fast charging to keep the Yak in the air and when the wind came up and the sun popped out the lift was so strong even the amateurs could maintain altitude. We had one flight of over an hour while passing the transmitter around flying back and forth between two slopes and using the heat of the plowed field in between. A good time was had by all but I think the Yak gained more converts than the Specter.
Oct 23, 2012, 07:37 PM
Registered User
Hi guys.

My "extra" KDA 22-20L arrived today and that's just as well because we've had thick fog all day. Just like the first, it's well finished and silky smooth. It's within 100rpm of the first which is well within the error range of my testing with different batteries and levels of charge. It will turn a 11X6 prop well over 8,000 rpm for 15-20 seconds on the bench and be just warm. That would give a calculated static thrust between 3.5 and 4 pounds!

Speaking of the new prop. I forgot to weigh the blades before I mounted them but they are lighter and spin faster than the old plastic blades. The blade profile is very similar so, unless they have a superior airfoil, I don't expect much difference in performance.

I've also been getting in a lot of flying with my foam Yak with the Turnigy 2834 motor. I just continue to be impressed with these little motors. The Yak is a bit under 800 grams but I wouldn't hesitate to use the motor on a sport/scale plane pushing 3 pounds or an even bigger scale sailplane. The DG 1000 I'm lusting after should be right around 3 pounds and I don't see a compelling reason why I shouldn't stick with a 28mm motor and use, if needed, a bigger battery for nose weight.
Oct 24, 2012, 08:39 AM
Earthbound Skyhound
StarHopper44's Avatar
"thick fog all day" <> Pete, where the heck are you anyway?

These motors & props you mention -- are these mods you're intending to use on your Spectre?

One more note - I've been biting my tongue on this'n but.....every time I see (and this goes a LONG way back before I started RC) the word YAK referring to an airplane I get a chuckle inside. The thought of one of these things flying? PRICELESS! *LMBO*
Oct 24, 2012, 01:30 PM
Registered User
I live in Minnesota, StarHopper.

I've had the KDA 22-20L in the Specter from the start and I just got an "extra" and a couple new props. i just mounted up the new motor to see how close it is to the original and I'm quite impressed. The 2834 was really kind of an impulse buy to compare it with the KDA and use in the 3D plane but I could certainly use it in the Specter. At 1250kv it spins most any prop just a bit faster than the KDA but uses considerably more current in static tests. I can actually hear it unload in the air and then it has bags of power without getting too warm. It would also make an excellent motor for the Specter or for a small sized hotliner since it really shines with slightly smaller props. It spins an old Top Flite nylon 9X4 at 10,300 RPM on 3 cells so it should really scream with an 8X6 and 4 cells. I, frankly, don't believe HK's claim that it will hold together at 40amps and 585watts. I just can't believe a $17.00 70gram motor will hack it. But, after the first couple of runs, I have gone to 32amps and 350 watts with an 11X3.8 APC slowfly prop without excessive heating. Even with the 10X4.7 that I use for longer flight times my Yak goes just about the same speed straight up as it goes straight down with the power off but the 11 inch prop gives it that extra bit if I want to impress a crowd.

It's this kind of performance that has me thinking I would need a much bigger glider to justify a 35-38mm motor. Obviously, one would want the extra mass in a design that requires it for balance and the extra heat dissipation in a hotliner or something. But, in my dreams and sketches, I'm thinking that a 28mm motor that will develop around 4 pounds of thrust with an 11 inch prop would work great stuffed in the nose of a 3 pound DG 1000 running a yoke through a hole in the nose rather than using a spinner. I could always saw the nose off later if I don't like the look or function of the bare yoke but I don't see why the drag would be that much greater or why it would look bad from more than a few feet away.

Speaking of Yaks... The name always reminds me of what my stomach would do to me if I flew in one.
Oct 24, 2012, 03:37 PM
Registered User

An observation about LiPos.

I know that it's claimed it's not necessary to cycle a LiPo like a NiCad and they are probably right when speaking of battery memory and discharge curves. However, having nothing better to do on a foggy day, I've been checking mine to see how they are holding up under the stress of 3D flying and they are in better shape than before. They are charging to .1 volt higher and their balance is much better.

When flying the gliders I rarely run the battery below 11 volts and rarely draw motor power for more than a few seconds at a stretch. I've run each of them down close to 10.5 volts a few times now and they are performing much better. With both motors and all batteries I'm getting almost 200 more RPM over the first 20 seconds of motor run which lasts through 2 flat out vertical climbs. It should be worth at least one "free" climb on the glider which can add up to a whole lot of flight time.

I thought that I was getting more power after the first few flights with the Yak but chalked it up to improving technique and, perhaps, my motor running differently under cooler conditions and/or breaking in. Now I'm convinced that it was my batteries that broke in.
Oct 27, 2012, 01:05 PM
Registered User

Wrong Parts

Well, I'm looking forward to getting my Specter in the air after hearing it's praise. I finally got the hardware package from Hong Kong but the parts won't work. The Props don't fit in the spinner and the spinner doesn't fit on the motor. Bummer. That took three weeks to get here. Looks like I'll have to go to the Hobby Shop and put up with their abuse for me buying " Chinese Crap" and have to buy their ultra expensive Tiwanese crap.

Oh! and I just noticed that the servos are too tall for the fuse! Crap! I thought I ordered all the items "recommended" for this plane. Pack it up. Send it back.
Last edited by EDintheclouds; Oct 27, 2012 at 01:11 PM.
Oct 27, 2012, 02:17 PM
Registered User
It can be a bit frustrating, Ed, but we'll get you through it.

One can drill out collet type adapters with great care. Are the shoulders of your blades too thick or too narrow? I don't recommend grinding down props but they can be spaced with washers.

One can get servos in in two ways. I was able to carve out the front piece of the servo tray and make the HXT900s fit by grinding away the lower corners. It's probably simpler to remove the tray entirely and mount the servos on their sides to a simple plywood floor.
Nov 03, 2012, 01:29 PM
Registered User
Name: DSCN0454.jpg
Views: 165
Size: 222.5 KB
Description: Too Tall! Even if I made a new mount plate, the spline and horn would hit the bottom of the wing.
Nov 03, 2012, 01:39 PM
Registered User


You can see in the above post that the Turnigy TGY-90S servos are way too tall for the fuse. and here, My motor fits the fues but not the spinner, and the props are too big for the spinner as well. Bummer.
Nov 03, 2012, 02:14 PM
Earthbound Skyhound
StarHopper44's Avatar
Looks like they sent you a too-small spinner. The correct one might fit those blades.
You might know this but, measure the 'shoulder' across the blade's butt, & that'll always be specified on spinner sizing as 'yoke width'. Ordinarily I'd suggest, if you have the tools, to cut the blades' hub down to fit the yoke, but from your pix that's quite a bit oversized. Max I'd cut from any hub is 1mm on each side. IF yours were within those parameters, I'd say you might can use the spinner after all. If you pull out the tapered collet, its leaves are 'sprung' and sometimes if it's a narrow miss in fitting on the shaft, the leaves can be spread apart a bit & it'll fit. Hard to judge that possibility (ie how close it is to fitting) from your pic, but with it being obviously so much smaller, prolly wouldn't even come close to working here.

I'd definitely contact their customer service if you 'accurately' bought the recommended parts, and demand they replace them at their expense. Including return postage for any parts they want back. (Odds are they'll tell you to just keep 'em.)

This all of course presumes you bought the parts from the store that recommended them, else all bets are off.
Nov 03, 2012, 03:47 PM
Registered User


I've been on Chat with HK for 1 hour 33 mins now waisting away my Saturday and no first flight in sight. I'm going to order these servos because they shoud fit the fuse and wings, but I'm worried about the torque and strength of the gears??

And a new spinner/prop. This is the motor I got. It fits, but it's a bit long.
Nov 03, 2012, 03:56 PM
Registered User
Hi, Ed. It does look like a bit of a pickle but all is not lost.

I think your best bet would be to mount the servos on their sides. Carve out the servo tray and make a floor slightly bigger that the servos, you might even be able to use the wood from the tray, and glue them down. I'm afraid that the spinner issue will require a further purchase.

Here's the spinner I'm using. If you look at the yoke you will notice that the prop bolts are secured with a nylon stop nut. The two HobbyKing spinners that i have, with those stop nuts, both have an 8mm shoulder width. Of course, the exact spinner I'm using is for a 3mm shaft so it wouldn't be the best choice but I'll supply the link so you can see what I mean about the stop nuts.

HK might have a similar spinner that will fit your shaft and props but I think your simplest solution would be to get a BB spinner from Esprit Models or another vendor. I can't tell whether your motor shaft is 3.2mm or 4mm but one of these spinners should work.
Nov 03, 2012, 04:05 PM
Registered User

Dont use those servos, Ed!

Here's a pic of mine with the HXT900 servos.

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