critterhunter

Another by Fiver...

Firebird style...brick with the odd cell centered on the end.

Speaking of batts...I check the temp of my nimh packs tonight and they were 160°F after full throttle runs. It feels hot but is that to the point of damaging the cells?

Also I got the stop watch out to check the speed of my 2409- 12T w/8x6E prop from 2nd to 3rd base (90ft). Was getting 60mph avg with a high of 66mph on the second run. This was with the stock 7-cell. I could not get the plane low enough with the 9-cell to check it's speed in the park. This flying chunk of foam is amazing! What an addiction.

critterhunter

Another Hagar Post (And I'm still digging for the message(s) comparing the 12T to the Mega)...

Now I have finally got a LIPO that can handle the amps needed to feed the 2409- 12T motor with a 7x7 prop
I got a 1700 mAh 20C pack on eBay for 29 USD. It was also from Hong Kong. Tested it earlier today. WOW!

I managed to trim the Stryker flat, and believe that the thrust line is also correct now. Speed is really scary fast. Need a lot of space to fly this thing.
Pulling up to bleed off some speed just results in the Stryker going skywards. I have also moved control rods for some extreme throw, inverted loops are so fast that the plane almost cartwheels It rolls like a drill even when going straight up.

I did not get much more than 5 minutes of WOT flying, but it feels a lot longer due to the amount of concentration required to keep the thing within visible distance and away from trees and ground.

This motor has got to be almost twice as powerful as the BP-21, highly reccomended for all speed maniacs

Hagar

wildjaych

cool posts, thanks for digging them up. Where are they coming from? the way past the limits thread?
I will try to get a friend to clock mine some kind of way to check speed. I never thought of that..... i think i have some orange cones somewhere and might be able to use that. wont be exact but damn close....... closer than guessing.

wildjaych

I swapped out the 8x6e prop for a 7x5 apc prop tonight and noticed a difference in speed, not a bunch, but it was faster. vertical was still awesome too. I will have to order more props to play with it but I will try to find one that cuts the vertical a little but gives more speed. I will post results.
My question is, if I go down to a 5" prop will I be able to still hand launch it? Seems like it will get weaker and need time to get up to speed..... i dont know just a thought.

I will try to clock it too and post results.

j

Mr.Pibb

Might try this:
http://www.walmart.com/catalog/produ...uct_id=4661205
I've heard of people clocking their planes with it. I haven't purchased/tried one yet...

TomN

Hi Critter, I have gotten the carbon tubes glued in with gorilla glue. It took some knife work to carve off the excess gorrila glue that foamed up, but the air foil seems realy solid now. I am ready to attach the elevons, but you said to use extreme tape folded over the trailing edge. There are 4 notches that the elevon tabs fit into the foam. Should I cut out the extreme tape in these notches, or just try to mold the extreme tape into these notches as I apply the tape? Are you using any glue on the elevon tabs, or are you just using the factory attachment system? Do you attach the motor mount so that it is even with the trailing edge of the foam, or do you go a little toward the nose? Thanks for the help.

fox6

I bought a an APC 7x4 prop that I thought I would try in my Blue Angel Stryker. It has the stock F-27C brushless motor and ESC. Does anybody see any problem. I realize I may loose some speed but I am looking for more thrust at launch. I am doing this until my 12T motor arrives. Also, if I go to the 8x6 prop, it looks like it would be necessary to notch out of the vertical stab mount to accomodate the longer prop.

wildjaych

no you wont need to notch it out, it fits just fine. Try that 7x4 prop and let us know how it goes.

critterhunter

I wonder how you guys keep getting the gorilla glue foaming too far out of your channels? You are either using too much glue or not taping over it good with Extreme strapping tape to seal it in. Once the tape is on put some weights over it to hold the rod in place better. It also helps to keep an eye on it for about thirty minutes or more and run your finger over the tape in various places so help smooth the glue out flat if it is trying to escape on you. Mainly, though, use less glue than you think you need. Here's what I do: Run a thin line of the glue into the channel bottom. Smear it around a bit with a que tip. Now take a spray bottle and mist the glue in the channel (don't get it on the body on the sides of the channel or the tape won't stick well being wet). If the channel is VERY clean and tight to the tube then you don't even need to spray the channel. Just mist water onto the carbon tube and lay it in there and that will cause the reaction. After you've worked with this glue a while you'll get a better idea of how much you need to fill a void while not over filling it via the foaming action. Another trick is to mix the glue with water and let it foam up for twenty minutes or so and then paint that into the channel. Since the foaming is just about done it won't grow up much more on you.

On the extreme tape: Just tape it over the notches and don't cut it. It doesn't have to dip down into the notches. Just keep it straight, because when you put the zips on it will pinch the tape down into the hinge depressions. No glue needed. Just make sure you zip the things down pretty tight, which may require pinching the foam a bit. You could trim off the excess zip end for better airflow but I prefer it to act as a kind of skid plate. Had concerns it might snag on landing and rip out but no such problems. Make sure you use a knife to cut a slit in the tape for the zips to slide through. They might break if you try to force them.

The motor mount's base should be flush with the trailing edge of the body. It also makes a great way to help line up the motor mount straight in relation to the body.

critterhunter

Mostly from the previous dark side thread before the current one. Just do a search in that thread for "12T" or "2409-12" and you'll find a bunch of references. I'll post more as time permits.

critterhunter

Remember that in general to increase speed you lower the length and increase the pitch, and to increase power you'd decrease pitch and increase length. This isn't an exact rule, various combinations of pitch and length might do better than others. Check back a few pages to a link I posted that gives the 12T prop sizes on a chart along with expected MPH and amp draws. Change the voltage to 10, though, for a more realistic listing.

Fighter Pilot

I’m going to guess that your going to be drawing more amps than the stock motor or the 25 amp ESC is designed for with that prop.

fox6

The Stryker flew okay with the 7x4 prop but I switched back to the stock prop. I am still having eratic hand launches. I thought by increasing throttle it would make it better but I found out that since there is not enough air moving across the wing to generate lift I wants to nose down and roll to the left. I have to make a very quick roll right and up elevator to keep it from kissing the ground. I am even increasing my launch angle and it seems to get worse. I was managing to get it in the air except for the last time where it nosed in. Once in the air however it flies beautifully. Any more suggestions would be helpful.

Fox6

Gryphon

fox6 ,

Are you throwing it with motor off and then using full throttle, or are you full throttle before letting go? I launch full throttle but I think about my hand every time before the launch. Thinking about it makes me move my hand out of the way faster to stay safe. Some do it this way; some hate the whole Idea of launch with motor on due to safety concerns. There has been more than one person hurting their hands and needing stitches at the very least.

Use some up elevator TRIM (on trans) and aim the nose up some(30 degrees or so) before/during the launch. Do a firm throw, move your hand out of the way fast. Re-trim after you get up high.

You may want to also explore aiming the right wing down ever so slightly during the launch to buy you a little more time.

Gryphon

TomN

I was at Walmart last night, and they had the Hot Wheels radar guns for $ 29.95. The gun has 2 switches. one switch controls readout either MPH of KPH. The other switch controls range. The close in range is for radar shots of hot wheels cars on the little race track. The other range is for taking radar shots of kids on bicycles, at least that is what the pictures show. The box says that it can shoot speeds up to 100 MPH. Now if this radar gun has enough range to shoot an airplane 100 feet in the sky I am not sure.

critterhunter

A friend of mine that I fly with has a college degree in high voltage electrical engineering. He does stuff like re-wind large generations for a power company. Not that it matters but figured I'd let you know he isn't a newbie at re-winding brushless motors. Anyway, he's just re-wound an 18T (12T is the same motor, just has different winds so it will work with it too) for more speed, power, and efficiency. Saw it fly on his Stryker yesterday and it was smoking fast on a 7x6E APC prop with real good unlimited verticle. I didn't want to guess but he claims the speed is about 100mph. Not sure what prop he was using at that. Anyway, here's a bit of data on what he did for those interested. He claims efficieny is above 70%.

The specs on the rewound 12T motor:

7 turn WYE terminated
3 wind 28 AWG wire (ie 3 strands of 28 AWG per phase)
Idle Amps - 1.5
KV - 1650
With a 7X6 prop amps = 24
With a 7X8 prop amps = 31

This wind is noticably more powerful and efficient than the 12T's standard wind.

tims880

So I have an extra 12t.......would he do it for others?

critterhunter

He's big into teaching. If you follow the link I provided a page or two back he wrote a document on how to re-wind.

critterhunter

Got around to flying the build in this thread the other day on the 12T again. Wow, I'm very impressed with this motor on the 8x6 APC E. Speed is plenty enough for me. I had a servo POT problem (again) that was causing one elevon to not return to neutral every time so it was fun flying it. Ended up nosing in at WOT. Nose and canopy were a good four or five inches into the ground. Plane bounced a good five feet from the impact. The body held up fine with just a little distortion at the front area where the nose sits. Canopy came unlgued from the battery hatch but didn't break. First time I've broke a 27C motor mount (slightly) but there was no foam damage to the body thanks to the carbon rods/extreme tape. A friend remarked that the plane should have been a pool of foam after that hit.

Anybody else try a 7x7 or 7x7.5 APC prop on the 12T yet?

tims880

I just ordered one 7x7. The 6.5x6.5 seems to be the hot ticket for the 12t. You loose some vertical, the speed is awesome.

wildjaych

the 7x5 is faster than the 8x6e. I didnt order any 7x7 or 6.5x6.5 props but I just got an assortment of 5" props with different pitches and a 6x4. I will try them if the wind ever dies down here and post results.

thanks for the info tims880.

Wastegate

Another cheap motor option I haven't seen mentioned in this thread is the Komodo 278 V2 self build motor. It's simple to build and produces great results when wound with 20AWG wire in a 6 turn wye configuration. I'm at an altitude of only 100 feet so run an APC 5.5x4.5 which draws 27 amps but those at higher altitudes could probably run with a 6x4 or 6x5.5. Level speed is much better than the 2409-12 but vertical isn't as good. This motor is relatively quiet as well.

HTH

tims880

Ok with the 12t the 6.5x6.5 is the fastest! Tested 7x7, 7x5,8x4,6x4,6.5x4.
Now the most fun factor is the el cheapo gws 8x4. This prop is way too thin and flexes under full throttle, But the noise created is so cool!

Hagar69

Tims880,
Did you get any amp readings with the various props?
Where did you get the 6.5 x 6.5 prop?

Hagar

critterhunter

Careful what type of prop you use on the 12T. Most GWS props are too flimsy and could take an eye out. I tried a GWS 9x4.7 on the 12T for my Mustang and it could only handle about 2/3rds throttle without sounding like it was going to explode. Even the APC SF props might be risky. The E or sport series should be fine, along with Master Airscrew props. By the way, they now come with prop rings like the APC (It's about time!) so they may be worthy checking out. They seem pretty stiff.