critterhunter

How many amp ESC did you have in it? As per the build photos and instructions on here I am using a Tower Pro 30 amp ESC but added an extra heat sink to it. So far so good. You're right, though...if you are buying an ESC for this motor I'd opt for a 40 or more amp model. Otherwise you need the extra heat sink and to make sure it gets good airflow.

I've decided to probably shave down the current build much like my friend's. I can cut a good bit of the 27 ounces off, eliminate the damage in the front, etc. One tip: Notice he has the verticle fins on the wing tips. If you go this route I think you can make them much smaller than where they are stock. I might be wrong but I would think they have much more control over the stability of the wing being at the tips and thus can be much smaller? Another good way to streamline the plane. I'll do that, fill the hand holds, shave down the front end, etc. Might pick up another 15 to 20 mph or so.

wildjaych

I had the towerpro 30 amp ESC in it and I put a heat sink on it and strpped it to the top of the rear cover so it was on the outside. I dont know maybe I just got a bad one or something.

I built mine pretty much like yours. the only CF rod that I left out was the one from nose to tip and I did use quite as much tape, i didnt tape the whole body. I am waying in just a hair under 21oz with a JR receiver, united hobbies 20c 3S2200 pack, and HS55 servo's. I know they are lite for this application but it is all I had to start with. I will change out the servos if the speeds come up with everything working right.

critterhunter

Yea, I think you'll find the HS55s a little light for a brushless Stryker. Just about everybody uses HS81s. Many used HS 81MG servos. I use the non-Metal Gear ones and have only stripped a few due to very bad wrecks. I think you can throw the metal gears into a non-MG HS81. I would have already but my local hobby store doesn't stock the MG gears all the time. If you don't land hard the HS55s should hold up for a while. I do love HS55 servos is lighter builds or planes with less speed. I think I threw those into my Mustang.

One trick when adding the extra heat sink to the top of the stock ESC's. Don't peal off all the heat shrink to the sides. I just cut a big enough square on top for my added one. If you cut too close to the sides I think it might allow the stock one to lift from the electronics as the heat shrink heats up and flexes. Not sure if it's glued to the components but just in case. Maybe you got a bad one like you said. Check out the sword/pentium ones on donsrc.com. They are SO much better than the TP speed controls for near the same price.

Anything under 21 ounces is good as you are beating the weight of the 27B. I think it weighs 21 to 23 ounces. Same with the C model.

fox6

Hey Critter,

I just finished building a modded out Stryker fuse according to your directions. I overlooked one thing. The CF tubes going from wing tip to wing tip are not flush with the wing surface. They are just short of 1/8" above the surface. I was afraid of melting through the foam. Do you think I will have to start over with a new fuse?

Fox6

TomN

Hey Critter,
Nice job on this thread. How much flight time could I expect with your build at moderate power usage using the 12T? Also, how would the Mega 16/15/4 compare power wise and flight time wise to the 12T?

critterhunter

The tube being raised above the foam some won't matter much. Sure, you won't be as streamlined with the airflow which might shave a tiny bit of speed off the plane but it won't matter much.

I fly the 12T full throttle almost all the time and flight times are very long on a 2200ma 20c 3 cell pack. As I've said before, I find myself wishing the pack would die so I can land and have a smoke. You won't be let down by how long you fly at full throttle, let alone if you keep off the throttle a lot as you said. I haven't timed my flights lately so I can't tell you how long of run time you get at WOT.

As far as Megas go, I know very little about them. However, I have read in the past that the 12T was a Mega Beater in speed and power on the Stryker. Which Mega they were talking about I don't know but this was using a 3 cell on both. If you look in the dark side thread there is recent conversation in the last few days from one guy who was let down with the Mega, I believe. Not saying it isn't a great motor, just that I prefer a very cheap yet powerful motor. The 12T is all that.

TomN

Thanks Critter,
Is there a certain brand and size of 3 cell 2200ma 20C battery that you would recomend? Did I read somewhere to get the narrow pack. Also would stepping up to a 35 or 40 amp ESC relieve the necessity of having a heat sink you used on the 30 amp ESC? Is the stock f-27C prop adapter OK to use or is there something better? I think you said to use a Maxx?

critterhunter

Use the Hextronicks $32 2200ma 3 cell 20C packs from United Hobbies. The price is as good as it's going to get and they'll work fine. Any 3 cell lipo should fit with no problem. The 12T and many other motors have a 3MM prop shaft. Any 3mm bullet style prop adaptor should work fine, though I prefer a type that has a set screw on it's side where you grind a flat spot on the motor shaft for it to rest against. Yea, a 35 or 40 amp speed control would be a better choice and then you don't need to worry about adding a heat sink to it. It's still a good idea to glue the ESC to the chamber floor so that the smooth (heat sink) side of the thing is on top and thus exposed to airflow.

Fox6 (and anybody who has built a stryker using these mods), I would very much like to see some photos of your bird along with a ready to fly weight. Thanks.

fighting falcons

Critter,

I had trouble veiwing the picture of your friends stryker with the 450H motor on it. Could you possibly pm it to me becuase I still don't know how I should mount mine.

wildjaych

yeah send them here too or just post on the thread.

wildjaych

Here a few pics of my build. its been too windy here to fly so I had the time. I just got the CC45 ESC in and got it installed. the motor seems to be working fine with the new ESC. I will post reseults of the flight. I went ahead and mounted the 45 ESC to the top with a zip tie to keep more air going to it. I guess it will help.

If this 12T motor doesnt put out like I want then I will try the 450H motor from donsrc.com

Fox6,
I had the same problem with my CF rods not being flush ( mine expanded out due to too much gorilla glue) I taped over the rob and I dont seem to notice anything when it flies but I am not at real fast speeds yet. so I will see once I get to fly and let you know.
Let me know if you have any problems with it.

critterhunter

A friend of mine bought my 3200 k/v motor off me which I never got a chance to try. I'll be picking up another sooner or later. Anyway, the motor went bad due to some windings after a few flights. He decided to re-wind it and in the process wrote a very good tutorial on re-winding brushless motors. The thread walks you through winding a motor with photos and gives explainations of winding different motors for different performance traits. It's well work the read and can be found here...

http://www.rcgroups.com/forums/showthread.php?t=666877

critterhunter

Looking good! Reminds me of another plane on this thread. I noticed you didn't use Great Stuff to spray in the empty front chamber. You might want to pick some up at Home Depot and do that. It will really help prevent front end squash even if you have the carbon tube from nose to tail.

The ESC doesn't need placed on top of the cover. Gluing it to the bottom of that chamber with the heat sink side on top will give it plenty of airflow. The F27C hatches really provide good airflow through the entire inside. Still, it won't hurt.

I just tried the link back a page to my friend's Stryker and it worked fine for me. Try again. I don't think he had the 450H motor on it in that photo, though. But, I think if you look back a page or two on here I provided some links to another flying wing with this motor mounted on it. If you still can't find those then email Don at Donsrc.com and ask him to see some pictures of his wing with the 3200 k/v motor on it for mounting ideas.

You'll be happy with the 12T motor on an APC 8x6E, I promise! Any ready to fly weights?

When you glue the carbon tubes into the body using Gorilla Glue (or any glue for that matter), it's important to add weights the entire length of them to hold them in place. I like to test fit them first to make sure they are flush with the body and not sticking out, but regardless you'll still need to weight them down. Using Gorilla glue (which is the best method...less weight and better hold), you could also throw your Extreme strapping tape over them before putting the weights on. Gorilla Glue doesn't stick well to this tape so you can always peal it off later to put on a smoother piece. The tape will keep the glue from migrating out of the channel and so I would use it if using Gorilla Glue. With other glues you can wait until after it's tried to tape over it since it won't be trying to foam out on you.

TomN

Hey Critter - Which brand of 35 - 40 amp esc would you recomend, something that does not have all the programing problems that you encountered, maybe something with instructions.

critterhunter

I'd say the best "cheap" ESC I've come across so far is the Pentium (Also called Sword) line. You can find those at donsrc.com or other sources. They all program the same, program easy, and have a general better look of quality to them than the Tower Pros. They also seem to have a much smoother throttle response. The Tower Pros are good cheap speed controls. It just can be a real pain to find the proper programming instructions for the many variations they have out there. As I said, they also seem to be going backwards in technology. The last one I bought was newer yet had less features than the previous "generation" of the same amp model for the same price.

TomN

Thank you Critter, The Maxx bullet prop adapter for 3 mm motor shaft, where could a guy find one of these? Is the clear tape you use of any particular brand? I found the extreme 3m tape OK. How about a source for the 8x6 E APC prop. Also a source for the carbon fiber tubes? Did you mention that for the 12 T motor that 30 amps is the max a person should go? Your help is appreciated.

critterhunter

Clear tape: Stick with the name brands like 3M. I've found that the cheaper stuff is thinner and not as strong. As always, use 3M Super 77 spray on the tape and wait a little before sticking it onto the foam to prevent any melting. Tubes: I pick mine up at the local hobby store but there are much cheaper sources on the net. Prop adaptor: Again, my LHS stocks those but you can find them on the net. Doesn't have to be a Maxx. Just look for a bullet style prop adaptor that has a set screw that is meant to hold it to the motor shaft. Grind a small flat spot on the side of the shaft where the set screw will rest to prevent slipping. The prop is held to the adaptor by torquing down the bullet head. Other types of prop adaptors will work, such as the type where the bullet head being screwed down causes the adaptor to crimp around the shaft. I've just had more problems with those types coming loose on me. APC 8x6E: I get that size at the LHS too but there are many sources on the web. Most hobby stores will order whatever parts or props you want if you just ask, and that will save you the shipping. Yes, the 8x6E is about the biggest prop and pitch size you'd want to use on the 12T. That's already overpropping the motor and pushing it's amps and wattage higher than suggested.

TomN

Thanks, Critter Our altitude is 4500 ft. The APC 8X6E would be doing less work in thinner air, and thus draw less amps, being slightly safer as far as overloading the motor at this altitude. Is that a correct statement, or do I have it backwards?

fox6

Well, I finally got my modded Stryker completed and flew it today. First hand launch......don't know what happened but it nosed into the ground. Probably a bad toss. Good news is that it basically just cracked the paint on the nose. It did come off as designed and so did the fused hatch. Next toss she took to the air and flew like a bullet. Most notable observation is that no energy was lost due to the elimination of flex in the wings, it snap rolled with authority.

If you can't tell from the photos, I modeled it after the Blue Angels FA-18 Hornet. I will list the specs and mods below. Thanks in great part to Critterhunter for all of his suggested mods. I don't have a an accurate means of weighing here but I will post weight tomorrow.


Receiver: Spektrum 6000
Motor: F27C Stock
ESC: F27C Stock
Prop: Stock
Servos: Hitec HS-81
Battery: 3S 2100 Mah Thunder Power
Paint: Testors Model Master (Bright Blue Gloss) 2 coats
Finish: Deft Spray lacquer
Decals/Accents: Die cut from Yellow Mono-Coat material

Mods:
Carbon Fiber tubes (length of fuselage and wingtip to wingtip)
Extreme Packing Tape (covering leading edge, trailing edge, motor mount, CF tubes)
Filled fore cavity with Great Stuff
Rare earth magnet to magnet (for attaching nose cone and hatch)
Hatch fused and reinforced with small pieces of CF flat stock
Vertical fins trimmed -- 7/8"
Battery compartment ledge melted away
Fake intake removed and angled for aerodynamics

For some reason....having problems posting photos.......

wildjaych

I flew my plane for the 1st time since I burned up the tower pro 30 ESC a few weeks ago. as i said above I ordered a CC 45amp ESC and am using the united hobbies 2250mah 3S lipo 20c and the 12T motor w/ a 8x6e apc prop.
I am still kind of disappointed in the speed of the 12T. It is still a lot faster than stock and it makes the stryker fly really well, I had fun and it climbs good but I guess i had my hopes up a little too much. dont get me wrong, for 15 bucks it is awesome......
I dont have a radar gun but my friend and I estimated its speed at about 45-50 mph maybe at level flight. Now in a dive it might reach 55-60mph. Still fun to fly but was expecting more maybe......
I will order the 450H from donsrc.com and see what kind of speed it has. Their web site says that he has one on a 20oz. wing and it does 95mph on 3S lipo w/ a 4.75x4.75 apc prop. I like it because its only 32.00. I guess I'm kind of like Critterhunter here, I dont like to spend a bunch of money on a motor. If I can get the plane to about 80-90mph I think i will be happy with that.... who knows. I will keep yall updated.

J

critterhunter

First, been asked in email to provide the original source for the 12T/mega comparison. I'm trying to dig up that message and re-post. As said, not saying the Mega isn't a great motor. It's probably much more efficient than the 12T (most Tower Pro motors aren't very efficient) which translates into less energy converted to speed/power. I do, however, remember reading that on a 3 cell the 12T did have the edge over the Mega in either unlimited V or top speed with the best prop size. Still, don't take my word for it until I do some digging. Maybe I'm wrong and don't remember right. I'm for cheap motors, regardless.

Good job on the Stryker maidens! I like to give the trim 5 to 8 "clicks" of climb on a hand launch to prevent the body slam you and I have both had. 50 to 60 or so is about right for the 8x6E. Keep in mind you can go to less prop size and higher pitch to get the speed higher. The trick is still keeping unlimited V if you want that. A 7x7, 7x7.5 or so might be in order. If you don't care about unlimited V you can go to an even higher pitched prop. Look back a few pages to the 12T prop size charting website. It'll give estimates to MPH on various prop sizes.

Post some pictures soon...

wildjaych

I will try the smaller prop maybe this afternoon. The wind here has finally slowed down enough. Thanks for all the advice you have given. I will post how it comes out.

fox6

Finally got an accurate weight of the Blue Angel Stryker: 25 oz. The digital camera actually lightened the color...it is actually several shades darker blue. It is almost a dead on match to the actual Blue Angel color.

critterhunter

Nice plane!

On the Donsrc.com 3500 k/v motor. I think you'll like it. I got to see the friend I sold it to use it for about three flights until he had a problem with a bum wind. The motor does look of very good quality so I was surprised by that. He's re-winding it. Don at dons rc has tested this motor so email him for info if you can't find what you are looking for in what I already posted in this thread.

I'm digging up some old messages on the 12T when it was still new and being compared to other motors. So, I'll be posting some of this stuff that lookings interesting or has good info. Still can't find what I'm looking for yet but you'll find this interesting...

(A Repost Of A Message By Hagar)

The testing of the 2409- 12T motor continues:
Took the Stryker out today, it was windy but one could say that I had more than enough power to fight the wind

First I took a short spin with 8x6 prop and 3S LIPO. Now the bird has really come alive, speed is very good and thrust is insane. Unlimited verticals at half throttle. I landed quickly as I do not want to toast my under-rated LIPO. New 20C LIPO is on the way

Changed to 7x7.5 and took another flight, now we are talking fast, scary fast. I have no way of measuring speed, but I would not be surprised to find out that it was going close to 100 mph. At full throttle it would still do unlimited verticals. I flew it at full throttle for about 30 seconds, then landed. Motor and ESC are still cold, but LIPO is now warm (not hot, just warm). I would think that current draw was close to 30 amps on that prop. This was a GWS HD 9075 that I cut down to 7075. I'm sure that a true 7x7 prop would perform even better. Will see if I can find one, anyone have a good online source for APC props?

One thing is for sure, this motor is way more powerful than the BP-21. I can highly reccomend it to anyone who want a cheap ticket to high speed fun. Just remember that you need at least a 30A ESC and 15C or better LIPO's at 2100 mAh.

If using a 7x6 prop it could be safe to use a 10C or 12C 2100 mAh or better LIPO. Speed and thrust is still better than with BP21.

Hagar

critterhunter

Another old but interesting message...

(Hagar Post)

Paul,
Actually I think you will see both speed and thrust improvements wiht the 2409- 12T .

Some simple math gives:
Himax kv2000 should give 20000 rpm at 10 Volts, with 6x4 prop you have 4 inches of forward movement on each rev. This gives a speed of 122 km/h
2409- 12T kv 1570 should give 15700 rpms at 10 volts, 7x7 prop means 7 inches of travel per rev. Speed is now 167 km/h

Of course I'm over-simplifying, we need to consider drag an propeller efficiency etc. But still we can clearly see that the 2409- 12T is capable of very high speeds. And it takes my 580 gram (with 3S LIPO) Stryker straight up. I can go up and almost loose it out of sight in only a few seconds

I have a lot of fun soaring with it now, just bring it up high and cut the throttle. Then glide down. Loops and rolls can be done just by diving a little to pick up speed. Great thing about glding like this is that I can now get longer flying time out of a pack even if the current draw has doubled.

Hagar