HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 10, 2010, 01:54 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Thanks Mr B and Ian for the ground tip. I had a suspicion! I'll give it a shot. Fingers crossed.


I have 7x4 props on their way to me now, so I will test the motor I have first. I really appreciate the comments and help...

Mr B that motor weighs 125g! almost double the one I have now. Think I'll try the 7x4 and then see how to go from there. Maybe you can launch it for me . Too scared to do it myself...
Gree is offline Find More Posts by Gree
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 10, 2010, 02:03 AM
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,716 Posts
One thing you have to remember when launching any power plane is to
actually *throw* it hard. A lot people forget to do that because
it feels like it'll just fly out of your hand when it's throttled up because it's
already pulling. The problem is if you just let go of it, the wing still has zero airspeed
(particularly with a pusher) and will stall, and the prop is
probably partially stalled. If you can give it that extra boost before
it leaves your hand, it'll be that much closer to flying.

ian
Daemon is offline Find More Posts by Daemon
RCG Plus Member
Old Dec 10, 2010, 03:35 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Well Thanks the ground info helped but has not solved the problem... Check out the comparison below between the 400mW tx (which has 8 channels), and my 300mW 4 channel receiver I use on my easy star...

new video tx - frustratingly close, but no cigar...
http://vimeo.com/17668275

old faithful video tx - rock solid hooray!
http://vimeo.com/17668837

I just can't get the thing any better than that! It is almost as if the thing can't quite tune in properly. Hmmm you don't think there is an incompatibility between the receiver and the tx do you?

I think I am at the point of conceding defeat with this one. Wasted many hours on it. Perhaps the water did damage it after all...

Unless it is something to do with the fact I removed it from its aluminium case? Surely not?
Gree is offline Find More Posts by Gree
Reply With Quote
Old Dec 10, 2010, 05:06 AM
Flying Monkey
Mr_B's Avatar
Australia, NSW, Sydney
Joined Nov 2009
737 Posts
Quote:
Originally Posted by Gree View Post
Unless it is something to do with the fact I removed it from its aluminium case? Surely not?
AAArrrrggghhhhh



You need the front cover on the 8 chanel RX there Gree . It keeps noise out of the oscillator. So you def need that bit. It's just the Big heavy outer case you don't need. Just make sure it doesn't get too hot when running it with no airflow over it.

We'll get you there

B
Mr_B is offline Find More Posts by Mr_B
Reply With Quote
Old Dec 10, 2010, 05:22 AM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Yeah it did the same thing with the front case on too... Will try it again though.
Gree is offline Find More Posts by Gree
Reply With Quote
Old Dec 10, 2010, 05:33 AM
Flying Monkey
Mr_B's Avatar
Australia, NSW, Sydney
Joined Nov 2009
737 Posts
Qn Gree ?

Was the 8 chann the one that went in the water? Which reciever were you using? The 8ChanTX works best with the 8ChannRX. If it's the case that you hit the water with this 8ChannTX, it could also be out of tune. Is is daylight out? If it was then the tx is out of whack then.

Cheers
B
Mr_B is offline Find More Posts by Mr_B
Reply With Quote
Old Dec 10, 2010, 10:05 AM
Flying FPV from the lab.
aaron_gx's Avatar
Canada, AB, Lethbridge
Joined Jun 2008
2,117 Posts
my skyfun draws a total of 342watts, and has enough jam to go vertical for about 5-6 seconds, which is just perfect for me. However, I think my skyfun is also a very light bird. I will weigh it all up and see what it comes in at.
aaron_gx is offline Find More Posts by aaron_gx
Reply With Quote
Old Dec 10, 2010, 03:04 PM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Hi B,

Yes the 8 channel was the one that hit the water, but no it was quite dark inside, however the clearest picture is slightly darker than it should be. I have a feeling that it just won't tune in properly...

I think I should buy a 4 channel tx - thing is I don't think it will be here in time for my upcoming trip


Aaron, a weight would be useful! I'll weigh mine (as close as I can anyway) too soon. I am not expecting vertical with this motor! But MrB's suggestions are not too bad, a lower kv so I can swing a bigger prop. We'll see what kind of watts I get with the 7x4.
Gree is offline Find More Posts by Gree
Last edited by Gree; Dec 10, 2010 at 04:09 PM.
Reply With Quote
Old Dec 10, 2010, 07:59 PM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Well, I have decided that either the tx is damaged from the water, or it being 8 channel and my rx being 4, they don't like each other much.

So I am on the lookout for a 4 channel 1300GHz video tx in AUstralia that I can get before Thursday! Anyone??!
Gree is offline Find More Posts by Gree
Reply With Quote
Old Dec 10, 2010, 08:10 PM
Flying Monkey
Mr_B's Avatar
Australia, NSW, Sydney
Joined Nov 2009
737 Posts
Quote:
Originally Posted by Gree View Post
Well, I have decided that either the tx is damaged from the water, or it being 8 channel and my rx being 4, they don't like each other much.

So I am on the lookout for a 4 channel 1300GHz video tx in AUstralia that I can get before Thursday! Anyone??!

Might be able to help you out there.

B
Mr_B is offline Find More Posts by Mr_B
Reply With Quote
Old Dec 10, 2010, 09:29 PM
Fly Like A Thing Posessed!
NightRunner417's Avatar
USA, FL, Fort Myers
Joined Nov 2010
1,777 Posts
Not to hijack the thread in any way, but I wanted to share a little something I did to my own Skyfun tonight. I'm building mine up for FPV just like Gree, and am slowly refining the system. I've had it up in the air with the FPV system fully working about three times (all in the same morning) and it did work very well, but was hard to launch and maneuvered like a pig so I am going to do some motor power upgrading within the next few days.

Anyway, on that morning, one particularly hard crash shattered one of the aileron servo covers, and I discovered (don't know if it was THAT crash or what) that one of my servos has apparently a missing gear tooth now. It knocks when I exercise it and has a little loose spot right in the center of the travel range. I decided to eBay myself some replacements (HXT900), and while I was at it, I thought, "Wouldn't it be nice if I could TOP mount the servos so that they are no longer a prime target for hard belly landings?"

Well, folks, I don't have the HXT900s yet, but I went ahead and did the mod anyway with the existing servos. It was DEAD easy, really.. Just had to shorten the control rods a bit. The cables even go down the same track as before, no problem. Here's a shot of the end result, and I have to say, I really like it. I don't feel like I'm going to beat up the entire servo system every time I land now.

Also, here's a shot of the plane as a whole. I've been trying to keep it as "stock looking" as possible, but part of the work involved cutting away some of the rear part of the canopy foam. I don't care... I care that it flies and does what I want it to do. It's too late to worry about looks anymore anyway with all the crashes I've had. This plane is what I learned to fly RC on, so she's taken a few hard ones. She's been very fair to me, I must say, lol.

FPV system is an 800mW 1.3GHz vtx from New Gen Hobbies, and a KPC-DNR700 camera from Protection Depot. No OSD yet, but am planning on it for the future.

Avionics as it stands now is stock motor, Hobbywing Pentium 40A esc, stock
receiver, stock servos.

Soon as I get my parts in, it will change to a Turnigy HXT2835 2700KV motor and HXT900 servos for the ailerons. Eventually I want to go with a long range radio control system like the EzUHF or Dragonlink, but that like the OSD is a ways off.

Oh, I'm also using the standard cheapie video receiver and a pair of EVG920E goggles, but haven't actually flown FPV with them yet. I'm waiting for a little more testing and improving before I am so bold as to try that. For recording, I use my laptop and an EasyCap USB adapter. I record so far with Windows Media Encoder, but after the difficulty that my video editor had with the wmv file (I really do NOT understand why), I may just go with AMCap and do some rigorous testing until I find a codec solution that doesn't drop frames on me. If anyone has any suggestions to that end, please feel free to suggest away.

Rick NR417
NightRunner417 is offline Find More Posts by NightRunner417
Reply With Quote
Old Dec 10, 2010, 09:47 PM
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,716 Posts
If it really "handles like a pig" it's probably more a matter of being nose
heavy than seriously overweight. Wings and planks (this being a combination
of both) are very sensitive to CG. The problem is, the CG is so far back
on this plane, that combination of camera and two batteries in the fuse
will easily make it nose heavy, especially with that little tiny motor on the back.

ian
Daemon is offline Find More Posts by Daemon
RCG Plus Member
Old Dec 11, 2010, 06:58 PM
Fly Like A Thing Posessed!
NightRunner417's Avatar
USA, FL, Fort Myers
Joined Nov 2010
1,777 Posts
Agreed, Daemon, I do believe it may be a bit nose heavy. I'm thinking that the new motor will help a bit with this, and I'll be looking into some other possibilities as well. I did however notice that the plane was showing signs of being heavy beyond what the stock motor was intended for, and was slower and less climby. It made me a bit nervous that I was going to constantly stall it out, which added considerably to my crash factor (I do way worse when I'm nervous). I guess I'll find out on Monday, because my parts order from HK is currently at the post office waiting for me to have a chance to go get it. I'll be the proud owner of the new motor, two new 2200mAH 3S lipos, and some XT60 connectors so I can make all my stuff universal.

In other news, my new servos came today! That's got to be one of the if not THE fastest eBay delivery ever. They replaced the stock VTS-05A servos perfectly, size wise, and are only a bit taller than the stocks were. No more knock in the right wing servo now, and they're noticeably faster to move. They're also a bit louder, especially noticeable if they rest a bit off and buzz, but who cares. I like em. I also like being able to see through the casing.

Now I also have some extra servos for a camera pan setup, which can go neatly on the left hand stick horizontal movement which is presently tied to unused channel 4. :-)

I probably won't be flying again until Tuesday morning, but I should have a little better idea what I have on Monday afternoon when I get everything put together. Who knows... If the weather is nice enough and I get done soon enough, I may just go ahead and give it a try before dark.

Rick NR417
NightRunner417 is offline Find More Posts by NightRunner417
Reply With Quote
Old Dec 11, 2010, 07:37 PM
Registered User
Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,948 Posts
Best of luck with it Rick. Your mod sounds good too. I may do it later down the track once mine take a bit of a beating... I can't believe you got it off the ground at all with the stock motor!

A friend has offered to loan me a 1.3GHz tx, so I should be flying by next weekend!
Gree is offline Find More Posts by Gree
Reply With Quote
Old Dec 11, 2010, 10:07 PM
Fly Like A Thing Posessed!
NightRunner417's Avatar
USA, FL, Fort Myers
Joined Nov 2010
1,777 Posts
Thanks Gree, best of luck to you as well!

Don't I know it about getting it to fly with the stock motor, lol... Believe me, it wasn't easy. I'm frankly not sure just exactly what I did differently except changing launch spots, haha, but it worked every time after that. Anyway, I'll be looking to see how you do and crossing my fingers for you!

If you're interested, here's how I did the servo mod:

Turn the plane over, and remove one of the servos. Pull the tape that covers the servo cable, disconnect the cable from the receiver, and just pull up on the plastic servo arm and wiggle and it should slide right out, servo holder and all. Now, look down into the hole and you should see that only a thin layer of foam of the topside of the wing keeps that from being a hole all the way through. All you have to do is continue this line of thought with a sharp knife. Carefully cut through the remaining 1/4 inch of foam, so that you have a rectangular hole all the way through. Now turn the plane right side up, and cut just into the side where the track is that the longer part of the servo holder cup slides into. You're just continuing this track all the way through the wing. Now you should be able to slide the servo cup into the hole just like it does from underneath. Press firmly so that the rounded parts of the servo cup (where the screws fit into) make little impressions into the foam. Use the impressions as a guide to dig a little of the foam away. Slide the servo and holder back into the hole, and it should fit really nicely and tightly, like it was all meant to be.

Now you'll need to flip your servo arm hardware around so that everything that was on the bottomside is now on the top. You'll need two new screw holes in your ailerons to make this happen. You're going to find that now, your control rods are too long. I cut about a quarter inch off each of mine at the bent ends, and just made new bends, rather than to cut threading off the straight ends. Adjust the final lengths by turning them in or out until when your sticks and trims are centered, the ailerons look nice and centered out. It may take some playing around to get it all right, I know it did for me. Check out the travels of both ailerons against each other to make sure they balance reasonably well when you work the sticks, and call it done! It's really not all that hard at all and no more big, delicate, and vital targets on the underside for impacts to destroy before their time. :-)

I'm considering making some kind of servo covers for the newly topmounted servos (impacts will still happen, just less often), but the Skyartec covers no longer fit due to the changes in height even with the stock servos. Something shaped like a rounded tipped cylinder cut in half might work really well. I'll keep my eyes out when I go shopping sometime.
NightRunner417 is offline Find More Posts by NightRunner417
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Finally flew my Skyfun FPV aaron_gx FPV Talk 44 Oct 11, 2014 05:20 AM
Build Log First FPV build - JP Green Sleeve... Jonno271 FPV Talk 131 Dec 16, 2010 11:32 AM
Discussion How to build heavy Duty Antenna Tracking pod for Eagle Tree FPV? ganapati08 FPV Talk 6 Oct 19, 2010 12:24 PM
Gallery Scratch build EPP wing for fast FPV catching up with the winds tushev FPV Talk 4 Oct 18, 2010 10:32 AM
Discussion How heavy is your FPV Skyatec SKYFUN? aaron_gx FPV Talk 2 Apr 24, 2010 11:44 PM