RE: F27 STRYKER -Way Past the Limits Part 6 -Go deeper in to the Dark Side...

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deeper in to the Dark Side...
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RE: F27 STRYKER -Way Past the Limits Part 6 -Go deepe... - 7/11/2007 6:25:28 PM

Posts: 2542
Joined: 9/24/2004
From: Brook Park, OH, USA
Status: offline

I'm keeping this re-post in the Dark Side thread for now until we produce a schematic and further info. Then I'll create a new thread for it. Please DON'T PM or Email either of us for making one of these for you. It'll be easy enough for anybody to do with a few simple parts from Radio Shack once we throw the info up. I figure many of the Dark Side crowd will be very interested in doing this! Read on...

First, Alex...don't worry. I know you said not to throw up the schematic until you've done a bit more testing to make sure the device is going to be reliable.

Recently I brought up the subject of converting Parkzone combat modules to standard electronics with Alex. I had done some extensive searching on the net and the only conversion DIY projects I've seen were the two by RC-Cam. He's done an excellent job with that project, even adding several more features to the controller interface functions (lost model alarm, etc).

He has two versions of the project, one for the older modules which is pretty basic (but still more complicated than Alex's hack), and one for the newer modules with the added features I mentioned. The older, more "basic" modification will not work with the newer modules, and the newer project is overly complicated using a PIC chip, software, and other such components to add a bunch of features to the device.

It was interesting to note that the old project wouldn't work with the new modules, since the new modules are still compatible with all x-port equiped Parkzone/Hobbyzone planes. You would figure the trigger function would be the same regardless, but for whatever reason that project isn't compatible with the new combat modules.

His newer "pic chip" project is very nice, and he's done a fine job. Anybody with moderate soldering/schematic reading skills could build it, but most of us don't have a pic programmer and that's a major road block to your average electronics hacker working in the basement.

That's where Alex comes in. As I said, I've found no other DIY interfacing projects on the web for these combat modules. I was rather surprised at this because they are dirt cheap (like $20), can be found at just about any hobby store, and work very well. I happened to have two laying around (we discovered these were the new versions after exposing the circuit boards on them) that I had some moderate fighting time on between Challengers and Extremes. They were GREAT fun but I soon after moved onto standard electronics so they have been collecting dust in my toolbox. I've also got one of those night light modules from them which has like ten different lighting patrens and are very bright. As a sidenote, this device will also work with Alex's homemade device to trigger it.

Last night I took the modules over to Alex's house and he began to hack them. While he was doing some investigating I dug up a few threads for him that decipher Parkzone electronics but they weren't much use to what he needed to know, so out comes the osciloscope (I'm sure I spelled that wrong) and his multimeter. I had the important job of firing the transmitter while he checked frequencies and other readings on the Parkzone receiver and such. I've messed around with 555 chips here and there for timer circuits but what he was doing was WAY over my head. I just nodded yes a lot and acted like I knew what he was talking about.

So long story longer, several times Alex thought he had devised a way to generate a "fake" signal that the combat module would recognize as "fire". The device doesn't look for a simply on/off or high/low trigger at it's x-port input pin (there are four pins...signal in...signal out...and positive/negative power leads), but rather it wants to see a specific coded transmission on it's input signal at a specific frequency to fire. I would guess Parkzone has done this for the reason of preventing it being used by other companies. Probaby also why they grinded off the chip numbers on the boards so you can't tell what they are using easily.

After several false starts (sometimes the device would trigger the module, but fail after the third or fourth "fire" command), he finally found a way to get it to fire every time. You'll have to talk to Alex on the specifics, but I'll put the way I understand it in simple terms for God's less gifted like me. It's sending out a constant babble of "non-sense" over and over again at around the same frequency as what the combat module expects via it's input pin. Sooner or later a random combination of signal patrens fall into the proper language that the module understands as "fire" and does it's thing. Sort'a like a monkey typing on a keyboard (no jokes ), once in a while it's going to hit a random combination of keys that do spell a word.

Alex should be proud of himself because it appears he has done something nobody else has been able to do, unless you are willing to get over complicated with pic chips and such. Good job Alex.

If a plane is hit it's module will already scream for several seconds (very loud) to indicate it's taken fire. Normaly the module would also shut down the engine on the plane for several seconds (the reason for the output and input signal pins on the x-port), but at this time just hearing the thing scream when hit is good enough. Alex says he could easily add a motor disable function to interface with standard electronics later on, but for now this is going to work fine for us.

One final note: He's going to energize his interface circuit via a servo, which we'll probably have plugged into the gear switch. Flip the switch and his interface circuit powers up and begins to generate it's "babble", which results in the Combat Module being told to fire.

I'm sure I got some of this wrong and Alex is going to correct me. He always does. Once again, great job! You deserve a ton of credit.

_____________________________

If you believe in Global Warming then shut your mouth. All that hot air is warming up the planet, remember?

(in reply to Ace Dude)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deepe... - 7/11/2007 7:58:56 PM

Posts: 3
Joined: 7/10/2007
From: london, ON, CANADA
Status: offline

yea im still very new to electric flight and im always looking for a lesson, sooo what is a "c rating " on a lipo cause my 1700 3 cell is rated at 12-15c at a continuous discharge and 20c in short bursts but i have no clue what that is. and if its the battery that really makes the difference, what size should i be looking at to work with my eflite 40 amp? along with what gws motor should/could i use to get me most torque and speed?

(in reply to Gryphon)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deep... - 7/11/2007 8:26:37 PM

Rustye

Posts: 30
Joined: 7/3/2007
From: Uxbridge, ON, CANADA
Status: offline

Hi all, Thought I would give you an update on "HERMAN" the twin Stryker F27C. I have taken it apart, changed the thrust line to the motors - last time they were carefully measured by eye. I took Gryphon's advice and reversed one of the props. Acutally, I changed both props to APC so they were the same make.

I then bought a wing for another electric model - not sure what it was - but it looked like if I cut the ends off I could make wing tips for Herman, which I did. Next I talked to my brother, who is a stress engineer at Vought, and he confirmed that as long as my cg was ahead of my new center of pressue, I would be good to go. Acutally with the battery moved very close to the nose, it was pretty close, only needed a loonie (that's a heavy Canadian coin) embedded in the nose and off it went.

The first flight was a little rough as I pushed the elevator trim the wrong way, so it was sort of an adventure. After fixing that, I flew it again, and the wing tips are fantastic, and it is, um, well, bloddy fast!. There was no wind, and it is noticeably faster than my other single Stryker.

Today, I got a second Stryker battery that I will Y into the other one and make an enlarged cowling on the nose to hold the extra battery. Gryphon said that I need more battery, so now I will have that.

I have the radar gun ready to go....I am guesstimating that in level flight with very little or no wind, its 100 mph easy, and in a dive with a moderate wind, I think it will break 130. My radar gun has a big digital readout, so stay tuned......

Thanks to all that post here. This has been a fun experience so far, and even if I whack it tomorrow, it will still have been worth it.....

PS. I like that vectored thrust idea....maybe I'll do another one with twin ducted fans, and hang the blade thrusters off the back....hmmmm....

regards
russ

< Message edited by Rustye -- 7/11/2007 8:28:43 PM >

(in reply to racer_dan)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deepe... - 7/11/2007 8:49:55 PM

Posts: 183
Joined: 2/28/2007
From: Virginia Beach, VA, USA
Status: offline

quote:

ORIGINAL: racer_dan

yea im still very new to electric flight and im always looking for a lesson, sooo what is a "c rating " on a lipo cause my 1700 3 cell is rated at 12-15c at a continuous discharge and 20c in short bursts but i have no clue what that is. and if its the battery that really makes the difference, what size should i be looking at to work with my eflite 40 amp? along with what gws motor should/could i use to get me most torque and speed?

I'm sure others can provide much greater detail, but in a nutshell:

C is the capacity of the battery. So for your 1700 mAhr (1.7 Amp Hour) battery rated for say 12C continous discharge would be 20.4 Amps of current and for a 20C burst (typically 15 seconds or less) would be 34 Amps. So, for example, if you determine you needed 400 watts of power and want to do it with 3s (three cells in series) LIPOs which have a nominal charged voltage of 11.1 volts then you will need 36 (400/11.1) amps of current. So in this case, a 40 Amp ESC should be OK, but the batteries are questionable. And all of this is influenced by the motor and prop selections.

< Message edited by RCHubbub -- 7/11/2007 8:52:35 PM >

(in reply to racer_dan)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deep... - 7/12/2007 12:21:38 AM

Posts: 288
Joined: 2/18/2007
From: Novato, CA, USA
Status: offline

quote:

ORIGINAL: Gryphon

Medusa Motors......Expect a post when I get off work.

I talked to Stryker_Viking without knowing about his post above from 1a.m. to 2 a.m. last night (Eastern time). He didn't mention that he had done that post, but that was one of the main parts of our discussion.

I agree with some of what he says and I disagree with some of it.

Medusa motors are good motors, and I do believe that his longer and 50%heavier motor is marginally better(not sure) than mine on 3S and about equal on 4S, but not as good on 5S given the stock wing profile of Stryker.
I guess radar readings on 4S and 5S will clarify everything along with more wattmeter readings.

Later,
Gryphon

Hey bro, wouldn't you agree with me in a simplified explanation of he differences in performance is related to the kv factor.

Theoretically; Comparing two identical motors with the same resistance, but with different kv's would give:

* The lower kv motor:
Have more torque
Can swing bigger prop
Higher capacity pushing a high drag profile like Stryker
Better climb
Less maximum rpm

* The higher kv motor:
Less torque
Need smaller prop
Higher maximum rpm
Will unload better in high speed
Better suited for a profile with lower drag like a thinned Stryker or Funjet etc.

It would be like comparing a diesel engine with a gasoline engine, diesel have the raw power to go uphill or push a boat in a way no gasoline engine could...
Well, this is how I remember the laws of physics at least, what do you think?
Btw, I would like to believe your Mega is superior on 3S, but not on 4S and 5S...
Always eager to learn -
Stryker_Viking

_____________________________

~~~~~~~~~~~~~~~~~~~~~~~
- - - Altitude is still my best friend...

(in reply to Gryphon)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deep... - 7/12/2007 1:00:32 AM

Posts: 2041
Joined: 7/11/2003
From: Charlotte, NC, USA
Status: offline

Stryker_Viking, MEDUSA RESEARCH Comments:
Where do I start my friend: My comments are going to hurt a little, but it’ll be good for you.
I wouldn’t do it if you were not my friend. If it was one of the other guys, I might have tried to be more tactful.
So you drew first blood on MEGA, and if you were right, then I wouldn’t have said anything.
Here go the real facts followed by real analyzing of your own chart:
Your bigger and heavier Model MR-028-056-2800 is inferior to my MEGA 16/25/2 2650KV.

Sorry, it is true.

Some of the supporting facts are showed by your chart up there, some of it is not and I will include them. So listen up please.

First some of the reason for my tone is because I never posted MEDUSA Killer and you have done this (MEGA killer) repeatedly starting with the part5 thread. So hopefully it’ll be cleared up once and for all. No I don’t take it personally, but I’ve had to respond to your inaccurate posts more than once.
My tests were done with a battery that you bought from me. Remember the TP 4S-3300 22C that you said you wanted after I cycled it and personally flew with it less than 8-10 times.

So with that smaller battery that I logged my test with compared to the battery you used to do your testing, here is what I see:
You lost so much efficiency trying to run Graupner CAM 5.5X5.5(same as me) that you drew 250W more(nearly 25%) while spinning LESS RPM………At least you mentioned that in your post, but not in so many words.

NEXT you show that when I ran the Graupner CAM 6X6 prop, I made 1206W with pitch speed of 161MPH at 28290RPM. So now let’s compare that to your 5.5X5.5. It shows that while you drew 1/8 more power out of your battery (150W) you had 11MPH less pitch speed. I’m not even sure it is worth mentioning yet that the thrust difference is huge, that will come late on.

BUT wait a minute, How come you didn’t post my other 6X6 test run, the one I posted many times and also gave you the information. Let me refresh your memory. With CC80A ESC on high timing advance which is less efficient, I drew 1330W and 28800RPM with 164MPH pitch speed.
So now, lets compare that to your 5.5X5.5 run. Well it looks like while I was spinning a larger prop with more pitch I was still more efficient than you, because with the same power in 1340W +/- 10W, I had 14MPH more pitch speed. I’m not even sure that I should talk about the thrust difference yet. I’ll save that for a little later on, but soon.

Let’s go to your run on APC 5X5 1221W and 166MPH pitch speed. Compare that to my 6X6 run that you posted; 1206W 161 MPH pitch speed. I will ask you this: DOES OUR PLANES FLY AT 160+MPH ACTUAL SPEED OR MORE LIKE ABOUT THE 125+ TO 130MPH RANGE ON 4S ??????
Now that you agree we fly closer to 130MPH, does it make a difference between 161MPH and 166MPH Given the same power input to the motors? Didn’t think so. It’s about time to talk about the thrust:
***** 5” prop Vs 6” prop at about the same pitch speed and power intake. What do you think is the thrust difference? My friend, take note, THAT IS A HUGE DIFFERENCE. To some one that I didn’t like I would say to actually tattoo it somewhere…. You I love like a brother and a great friend.

But I’m not done yet with this post, there is more. I will make sure to never hear MEGA killer unless it is factual. So there is more clarification needed for you.

So now you can see that the higher efficiency that you are looking for compared to the MEGA has not happened at 5” prop for you. So let’s go look at your 4.75” prop.
You got your best efficiency at 4.75” prop, do you think that is the best prop for you at 130MPH? Do you think that prop will reach 130MPH in a Stryker?
If the Stryker was a thin wing, a good deal thinner and had less drag like a Funjet or something, then your motor MIGHT have an advantage. But I wouldn’t even give you that unless Radar runs prove it.
Not finished yet.

So lets talk about 5S…….What prop will you run then? 4.1” prop? Do you think at 140 MPH when the drag is going to be roughly twice that of 100MPH that the 4.1” prop is going to be ideal, or even enough?
It is not all about pitch speed, if you don’t have the thrust you will never reach the higher speed. It will be like doing a huge burnout at the drag strip, you can spin your wheels and go nowhere.

Lastly, I think you will hate me for this one, but I owe you this one: Are we talking about the same motor that you burned out and had to send in for repair??? It is not really a question because I saw it.

This brings me to the next point. MEGA motors run very COOL, more cool than Medusa motors. What the pics of the Medusa Motor does not show is that it is fully sealed. It is lacking the 4 very large holes in the front and lacking another 4 large holes in the rear.
Now I know I was a little sleepy with the blanket over my head at 1:30 a.m. but did you ask me (over the phone) if I thought that 100-140MPH air going through the inside of the motor made any difference in cooling it? Well I know I was not dreaming and YES, IT DOES MAKE A BIG DIFFERENCE.

That would be a disadvantage to a MEGA motor if someone wants to land and operate it in dirt and dust. That is why medusa and also some of the Military specified motors are fully sealed. That is a plus as long as they don’t get fried.
Since I don’t have data on your motor and 3S, I will say, like before , that your Medusa motor which is 50%heavier than MEGA 16/25/2 2650KV when on 3S will have a slight advantage (just to be nice like I’ve been). I am pulling that out of the air. Just because you over propped your motor on 3S once to get a big number does not make it right, or more powerful though.
But on 5S your Medusa has a disadvantage partly because of its KV being too high.

On 4S I knew I had the better motor but didn’t want to say it, because they were close enough. I was just very happy that because of hanging out with me, you tripled to quadrupled the power of your Stryker. The difference was close enough that I didn’t want to put your motor down. I think that extra and super long 480 sized 2800KV Medusa it is a great motor, no it is a fantastic motor, honest.
Recall how you picked that motor? My other friend said something to you a few times and you wanted to outdo him, not necessarily outdo me and you didn’t want to get the same motor. I made sure you knew to at least go for a low resistance motor which you did.
Great choice, but not only it is not a MEGA killer, but it is extremely close to being almost as good as the MEGA 16/25/2.

Just now, I read over your post again and saw the time of your post. I also just remember that last night I asked you to not post anything like that for a personal reason that I gave you. I said to give me 2 weeks.
So I see that you just put up another post with “it seems this and that” comments. Let stick to the tested facts my brother.
I kind of wish I stated a few more things, but those may have to be in future if this MEGA killer stuff continues.
I guess more detailed testing will be needed.
Take Paul with you when you are ready for more radar runs. Let’s compare some real numbers and see. Actually I just did that and none of it was theory but your own actual testing. Problem lies in your bad analyzing practices of the above data.
Lets agree to get off of this subject till we have verified some radar runs starting from now.
I will try to bust 120MPH on 3S. Will your motor hang with that?

****AS A REMINDER MEGA WINS USING A SMALLER BATTERY WITH LOWER "C" RATING. Imagine if I had ran a bigger battery. I have the same battery as yours and I will solder and start cycling it this weekend. Remember same battery as yours that we bought at the same time and we split the bill?
PUT THAT IN YOUR PIPE.

I expected you to listen to my request last night. I would have listened to yours.

Gryphon

< Message edited by Gryphon -- 7/12/2007 1:13:37 AM >

(in reply to Stryker_Viking)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go deep... - 7/12/2007 3:02:51 AM

Posts: 177
Joined: 2/19/2003
From: Somewhere, USA
Status: offline

Guys, it's just a $100 motor, lets not go crazy. Just chill. I'd be happy with 100mph. Will the Mega 16/25/3 do that with a stock F27C airframe? I have some 20C batteries and can always go to 25C or 30C batteries when they are available. I guess the big question is to get a 16/25/3 or 16/25/2.... The Afterburner is also a possible option, but it looks like the Mega has some advantages. I just realized that all of Medusa's ESCs are for brushed motors.

< Message edited by Ace Dude -- 7/12/2007 3:04:11 AM >

(in reply to Gryphon)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go dee... - 7/12/2007 4:33:18 AM

Posts: 183
Joined: 2/28/2007
From: Virginia Beach, VA, USA
Status: offline

We boys and our toys. Well I'm still very happy with my 67 MPH based on the Quiet Flyer article.

Gryphon,

I liked how the writer in the article had to push 600 or so watts to get to the magical 100 MPH level flight mark....pretty much just as you explained to me.

I know some of my questions might be mundane to you at this stage of the game, but if you get a chance I had a couple of more a few posts back that I would appreciate if you could take the time to respond to in case you didn't see them. Thanks

(in reply to Ace Dude)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go dee... - 7/12/2007 5:04:12 AM

Posts: 177
Joined: 2/19/2003
From: Somewhere, USA
Status: offline

quote:

ORIGINAL: RCHubbub

We boys and our toys. Well I'm still very happy with my 67 MPH based on the Quiet Flyer article.

Gryphon,

I liked how the writer in the article had to push 600 or so watts to get to the magical 100 MPH level flight mark....pretty much just as you explained to me.

I know some of my questions might be mundane to you at this stage of the game, but if you get a chance I had a couple of more a few posts back that I would appreciate if you could take the time to respond to in case you didn't see them. Thanks

So what setup/recommendations were made in the Quiet Flyer article?

(in reply to RCHubbub)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go dee... - 7/12/2007 5:24:33 AM

Posts: 183
Joined: 2/28/2007
From: Virginia Beach, VA, USA
Status: offline

quote:

ORIGINAL: Ace Dude

quote:

ORIGINAL: RCHubbub

We boys and our toys. Well I'm still very happy with my 67 MPH based on the Quiet Flyer article.

Gryphon,

I liked how the writer in the article had to push 600 or so watts to get to the magical 100 MPH level flight mark....pretty much just as you explained to me.

I know some of my questions might be mundane to you at this stage of the game, but if you get a chance I had a couple of more a few posts back that I would appreciate if you could take the time to respond to in case you didn't see them. Thanks

So what setup/recommendations were made in the Quiet Flyer article?

With radar, they have the stock Stryker C at 67.7 MPH level flight and 81.2 MPH on a 10 - 20 degree dive. They hopped it up to a Medusa MR-028-040-2200, a Phoenix 45, PolyRC 4 cell, 2000 mAh battery, and an APC 6x4 sport gas prop. This was almost a drop in conversion adding only 3 oz of flying weight and yielding 622 watts with a level flight of 103 MPH, and 111 MPH with slight dive. The author later changed the servos to HS-65s and the receiver to an AR7000.

(in reply to Ace Dude)

RE: F27 STRYKER -Way Past the Limits Part 6 -Go dee... - 7/12/2007 5:40:55 AM

Posts: 177
Joined: 2/19/2003
From: Somewhere, USA
Status: offline

quote:

ORIGINAL: RCHubbub

With radar, they have the stock Stryker C at 67.7 MPH level flight and 81.2 MPH on a 10 - 20 degree dive. They hopped it up to a Medusa MR-028-040-2200, a Phoenix 45, PolyRC 4 cell, 2000 mAh battery, and an APC 6x4 sport gas prop. This was almost a drop in conversion adding only 3 oz of flying weight and yielding 622 watts with a level flight of 103 MPH, and 111 MPH with slight dive. The author later changed the servos to HS-65s and the receiver to an AR7000.

Cool, thanks for posting. Perhaps the Medusa is a viable option after all.

My flight recorder is ready to not all I need to do is install it in my Stryker and take some measurements to see what the stock (F27C brushless) setup is doing.

(in reply to RCHubbub)