HK Specter 1800 - Page 19 - RC Groups
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Sep 20, 2012, 12:13 AM
Earthbound Skyhound
StarHopper44's Avatar
Originally Posted by peterlngh
BTW. I might just be imagining things but it seems like I have a little better roll stability with an aft CG. My guess is that providing more lift with the V-tail gives it a bit more apparent dihedral. It's a subtle difference if it's even there at all.
That's one of the standards with aerodynamic physics - fwd CG more stability, aft CG more maneuverability.
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Sep 23, 2012, 07:04 PM
Registered User
I finally got to try out the 11X6" prop and I am suitably impressed. I only use about 5 or 6 seconds to climb out.
Sep 25, 2012, 08:48 PM
Registered User
Haven't had much luck buying the correct spinner. I have bought 2. The 30mm one does not have the 6mm prop yoke. I hate to file down the prop just to fit. I then bought a 9 X 6 set and the diameter of that spinner is too small.

Any simple solutions. I am looking for a set? I have a 1000kv motor.
Last edited by YEAP CHIN POH; Sep 25, 2012 at 10:15 PM.
Sep 25, 2012, 09:01 PM
Registered User

Do you have a 3mm motor shaft? If so then the spinner I'm using would work. It has an 8mm yoke but I've used blades with a 6mm shoulder with two thin washers. I've also flown a few flights with a 28mm spinner and it doesn't affect performance. It looks a little funny if you get real close but it would at least get you in the air until you find the perfect spinner.

This is the one I'm using. It's 1mm too big but no one has ever noticed.

And this is the 28mm that I have as a backup. I have to use the shaft adapter from the bigger one but it would work with a 3.17mm shaft as is. It also has an 8mm yoke.
Sep 25, 2012, 10:14 PM
Registered User
What happened to the 32mm spinner that you wrote about. Could the blades fit without having to file down the root?
Sep 25, 2012, 10:53 PM
Registered User
I had made a mistake and said that the 33mm spinner was 32mm. So I have a 33mm and a 28mm that will accept props with an 8mm shoulder and two 30mm spinners that I use on my ASW-28.
This one...
Has a 6mm yoke and this one...
Has a 5mm yoke but it will accept the yoke from the one that came with the first. The first one can also use the collets that come with the second.
Sep 26, 2012, 02:08 AM
Registered User

Thanks for the quick reply. Its what I need.
Sep 26, 2012, 01:16 PM
Registered User
I'm always happy to help, YEAP. It took me a lot of mixing and matching parts to get the prop/spinner that I wanted and it would have been cheaper to just order from a more expensive dealer but, at least, I have several different combos that I can use if I break one or spin it off and lose it. I've also learned a lot about motors and props. Of course, my motor has enough power that it doesn't really matter which one I use but now that I have the 11X6" prop It really climbs like a warmliner or hotliner!
Sep 26, 2012, 07:18 PM
Earthbound Skyhound
StarHopper44's Avatar
I had a hotliner once......that is, until I actually saw a hotliner in action.
Then I had a warmliner.....& maybe should'a named it 'Luke'.

BUT (*heh heh*) ....
Originally Posted by peterlngh
I'm always happy to help, YEAP. It took me a lot of mixing and matching parts to get the prop/spinner that I wanted and ...
.... about that.
I've got my yearly allotment check on the way in and, have been working up my shopping list for some time -- the big annual one that replenishes all my used up bits & parts inventory, & pretty much tides me over for the coming year. One thing I'd planned was to put in a stock of folding blades; a couple pairs of each size - one to test as alternatives on whatever e-gliders I might acquire, leaving a backup set for sets 'assigned' permanently, plus replacement for damaged blades. The monetary boost is nonetheless limited so, gotta mind my P's & Q's as they say. So let me take advantage of the experiences of others that fly the types I do here, and ask:

If you (all) were gonna stock up on a couple of sets to have a good variety for that purpose - testing alternates - what good cross-section of blade sizes & spinners would you elect to have?
Sep 26, 2012, 08:13 PM
Registered User
Well, StarHopper, keep in mind that I'm relatively new to modern electrics though I flew glow engines for nearly 40 years.

My experience is that one wants to use the largest blade a given motor or engine is able to swing efficiently. Length and blade area are more important than pitch and, for a powered glider, I don't see much need for a pitch of over 6 inches unless one is using a large motor with a low kv rating. My KDA 22-20L 1,000kv gives a very good climb with anything from a 9X5 to a 10X6 but the new 11X6 just about doubles the rate of climb over any of the others I've tried without drastically increasing the current draw.

I also have a HobbyKing 2834 1250 kv currently mounted in my Extra 330. With a 10X4.7 it hovers, will accelerate vertically out of sight, and gets a bit warmer than I would like and sucks the batteries dead in no time compared to the KDA. It has held together so far drawing 32+ amps and over 330 watts but I'm not sanguine about it's chances of a long life despite the claimed power ratings from HK. So?

Assuming a 28mm motor of roughly 1,000kv, 20+amps, and 200 watts or more I would suggest a 10X6 or 11X6. With a higher kv and/or lower maximum power one would want to drop down to a 9X5 or 9X6. Any of those should give a static thrust of 1,000 grams or more. The calculated thrust for the KDA with 11X6 is 1.37kg and the 2834 with the 10X4.7 is 1.24kg. I did try an 11X3.8 APC on the 2834 but it got too hot to touch in about 10 seconds so I didn't even check the current draw. It gives a whopping 1.8kg of thrust at 8100RPM!

To answer your question on a selection: I would get 2-3 props between 9 and 11 inches and whatever spinners one can find within a few millimeters of a perfect fit that will accept the chosen props. I had to do some mixing and matching of adapters to get the setup I'm using on the Specter. All of mine came from HK and have been well balanced but, when I get my next glider, I'll probably step up to those offered by Esprit Models or Hobby Lobby. Now that I have some working knowledge it seem silly to save $15.00 on a prop/spinner that doesn't quite fit the nose of a $300.00 glider or get the most out of the motor. I haven't yet tried a bigger motor so I can't really offer much there.

P.S. I realize I don't have hotliner performance but the Specter does now climb faster than any of the warmliners I've seen. I'm getting as high as I want to go in about 5 seconds and I'm afraid to risk the airframe with full powered level flight much less a power dive!

Sep 27, 2012, 03:18 AM
Earthbound Skyhound
StarHopper44's Avatar
Great info Pete, & mucho thanx for sharing. I'm just before closing down fo rthe night (running on fumes!) but will comment further later.
Sep 27, 2012, 01:38 PM
what ya mean i have to land?
well,after much work my spectre flies really well now.rstripped all the covering off of the wing and tails,reworked the hinges and recovered everything,cut the nose and made a new firewall to mount motor to.ran the tail control wire out the top of the fuse for better movement,made servo trays so servos would fit without hitting the wing.using an e-flite 480-910kv motor with a 36mm turbo spinner and cam 10x8 prop,1800 4s batt and 50a esc.flies great now,straight up till i can't see it and glides forever.had to slow it down a bit cause at speed in turns it torques's a fun flyer when built right.heres a link for some good spinners and props
Sep 27, 2012, 02:29 PM
Registered User
Glad to hear you got it dialed in, oly. I'm still too lazy to change the pushrods so I have to rebend them every couple flights but, other than that, it's a pure joy to fly. Now that I have the 11X6" prop I'm averaging about 6 seconds for my climbs but, like yours, it will pull straight up out of sight though probably a little slower. One of the things that has surprised me is that it will handle a little extra weight better than I thought. I really can't tell the difference between a 116g battery and a 66g battery with the possible exception of slightly lower landing speed. If anything it's easier to fly in thermals with the extra couple ounces because it doesn't want to "blow out" of the thermals as much.
Sep 28, 2012, 12:10 PM
Earthbound Skyhound
StarHopper44's Avatar
Originally Posted by StarHopper44
Great info Pete, & mucho thanx for sharing. I'm just before closing down fo rthe night (running on fumes!) but will comment further later.
To continue....
Again, appreciate the numbers Pete. I'm curious as to whether you work with a good wattmeter (a la WattsUp or other brand) when you're testing your various setups? I've been relying on data I record (log) with my EagleTree system, which plots 2D charts of performance info.

While lab quality, it's nonetheless somewhat cumbersome in application in that it's mostly done (me) sort've after the fact in that I hook it up to as-bought stock setups 98% of the time, fly the rig, download the data & get a 'baseline' of info of how it performs, then start looking for improvements to make from there. It would be also good for bench-testing, which has its own issues as well, but I haven't gotten into that phase of it beyond some quick in-plane runups a few time (the 'other 2%') before maidening a particular model or two when reviews have indicated that plane's powertrain is iffy. I mean, if it's gonna fail, I'd prefer it not be mid-air & take the whole plane out with it.

Best of both worlds I suppose would be to get another ET logger for dedicated bench work. Oops - I forgot to preface by confessing I don't even have a wattmeter per se. I would have, first thing getting into electrics and was to the point I was researching which to get as best (ie less spendy) than 'The' WattsUp model....but money was particularly tight at the time. Before I decided, a couple of other things I did & was about to do gave me pause to re-think my strategy.

# 1, as sweet as the EagleTree was, its price looked absolutely prohibitive. BUT (always that ), I had started piecemealing my test equipment - first a voltage checker, then a slightly better one (selling the first) which would ride-along in the plane & give a performance review after landing (LiPo Voltage thru the flight, & lowest cell at any time) .... then a Digi-Cell Diagnostics Analyzer....each coming at around $20 a chunk a month or two apart.

Mid-stream something happened. A friend upgraded his ET system, and had a couple components he said he'd give me if I could use them. I did some thinking & the rationalization arose that, by the time I had all the instrumentation I'd planned to acquire in hand, I'd have spent prolly twice the cost of an EagleTree!
I'm gettin too long-winded with this so to leap to conclusion, I canceled my buying plan, sold off the non-ET components, saved a couple months & got the ET system, & here we are! Present plan with the check coming in shortly is to add a dedicated WattsUp 'type' meter to have as a portable, 'quickie' unit for my repertoire. Will be much handier to just plug in & take a few quick test reads than having to wire in & install the ET gear - removing the cumber so to speak - worth the investment IMO.

But central point to my earlier inquiry about the blades assortment -- the bulk of my 'big annual' buy will be thru HK-China chiefly becuz of availability of stuff I can't get elsewhere, and I can take best advantage of their good pricing to get the blades inventory on the cheap & spread the shipping costs in the process, rather'n investing heavily in the CADs & Graupner Carbons et al. Then thru testing alternatives (and metering) when I get a prop that really works well with a given model, upgrade it to the Carbons for that performance plus the added efficiency they provide. But key to that all of course, is deciding what inventory to get....hence the inquiry.

Gotta get out of here - work to do on my Messerschmitt in prep for our club's big fly-in tomorrow -- AMA/IMAA sanctioned Big Birds / Warbirds event. Forecast's for 40% chance of scattered T-Storms so we're dreading that -- you guys pray for dry weather for us, would'ja?
Peace - Out!!
Sep 28, 2012, 02:16 PM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
I use the Watts Up and really like it for measuring my system performance. I usually put the system together and then bench test it before a flight, trying different combinations to see that I don't over load and burn out motors (which I've done). I have not tried flying with the unit in my planes, that could be useful to get flight data but I imagine the numbers would be the same as static ground testing as I do test with the props on and swinging of course.

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