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Old Dec 28, 2011, 01:28 AM
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Build Log
Dynam 1200mm Spitfire

Well.. A few months ago nitroplanes had a sale on these dynam Spitfires for $99, and there was a discount code floating around for like 10% off, so this handled the shipping and I couldn't say no. 5 channel yielding retracts which would be bringing the cool to me and let me learn the ways of this retractable gear stuff on a cheaper airframe.

A week or so later the plane showed up. I put it together in about 15 minutes at my office and brought it home to hook up the rx and put some video gear in. After a couple of hours mucking around with the retracts I gave up and chatted with support from nitroplanes who agreed that after what I had tried that both of the retracts were toast and to send them in. Haha, how do you send them in when you can't fish the wire out of the wing?? So I got grumpy and moved the plane to the back of my garage for a little time out.

Fast forward a couple months and I've piled my twinstar in, the old t-28 in on its third fuse and generally an ok beater but it gets pushed around a lot in the wind. I'm not dogging it out, but it just isn't fully scratching the itch anymore. So I look over and see this thing sitting in the corner over there and decide to go to work.

** Alert, actual build log begins here **

I decided to remove the retracts, less weight. I also heard the stock motor could handle 4S. No brainer. I replaced the stock ESC with an old Castle Cremations Thunderturd 56 and disabled the built in BEC and hooked up another Castle product, the 10A BEC. I obviously didn't care about this airframe. Next up I needed to stiffen up the tail after boogering it up trying to screw it in. In the process I managed to CA glue the rudder control rod into place. Well hell. I centered up the rudder and called it good.

5 channels down to 3 channels, bank and yank baby! I dropped the old 200mW 5.8 TX in her with a little run of coax to a cloverleaf and put the 600 pixel WDR boardcam from sc2K on the readymade pan and tilt.

Right now I've got a couple of issues:

1: Camera sits too high to get any of the canopy in view. I'm thinking of going back to pan only to lower the height. I'm also thinking about going to a wider angle lens or something to squeek out a bit more pan and get more in the frame in general.

2: There is horrid quality with current video setup. It doesn't drop out, but see the attached screenshot to see the noise (other than the ESC noise) that is a constant through all of the frames. I'm unsure if that is the camera, vTX or cabling that is causing this. Needs to be remedied.

3: Need an OSD. Thinking about going eagletree simply for the airspeed indicator.

Pluses of this airframe:

It is a battery sipper. With the 4S 2800 mah battery, after 5 minutes of flight I only had to put back in 800 mah. I should easily hit 10 minutes and maybe 15 minutes of flight with this setup. Very nice for a plane in this style.

It is more stable (if you can believe it from the video) than the 1100mm T-28. I maidened it in 10 mph with gusts to 15 and this thing handled it much more gracefully than the tired old t-28.

So here are a couple of pictures of the finished product before the first flight, a snapshot of my DVR's interpretation of the crap noise I'm getting on screen and the uncut video of her first flight.

I must say, canopy or not it is pretty sweet to be staring down the barrel of that fuse and see the exhaust ports for that v16 Merlin engine out there. Yeah they are plastic, yeah the video isn't HD, yeah I'm maybe going 50 mph, but it is still pretty dern sweet.

FPV maiden of Dynam 1200mm Spitfire (5 min 17 sec)
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Old Jan 10, 2012, 11:36 PM
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Well I figured out what was wrong with my camera. If you try to power up a 12v camera with a 2s battery, things don't usually work correctly.

I also reverted back to my old pan-only set up because I really wanted this to be sitting within the canopy lines. You know, because flying FPV is so stinking easy that I actually want to see less while doing it and more of the airframe.

I've also gone through two OSDs on this plane. At first I dropped my Skylark Tiny II OSD in there and it really didn't work with the 4S battery. This was a bummer and I think there is a ground or power issue of some sort, considering I've got the 4S flight battery, the BEC doing its thing and a 3S cam/tx battery. Which later led to a bug to bite me in the ass on my next setup..

So I decided to slap in the old Eagle Tree. This exact system had worked very well in a retired airframe (seriously, not turned into bits like others before) and I never had a problem with it.. until after I had thought about it a bit.

With the ET stuff, they have a throttle position element that intercepts the connection from the ESC to the RX and gives a reading. What I didn't realize was that that that very point I would be introducing 3 different voltages into the eagle tree. 4S flight, 4.5v (or whatever) from the BEC and the 3S in the FPV system. Well.... this makes the whole system twitch. I think actually it was making the TS rx reset. Whatever the case I was super pissed when the thing spun up the prop on my table, which motivated me to re-bind my TSLRS system with the proper throttle settings. I digress.

Ultimately my fix was to just remove this connection to see if that fixed things, which it did. I then read somewhere after a search that I would just have to tee off of the signal wire from the ESC to the RX and feed that one wire into the ET logger to get the signal and avoid the thing spazzing out.

It also dawned on me that I was using this very same system when flying a beautiful Carbon Z Yak (a 4S plane) and this twitch happened in mid flight, making my pan servo go full right. I had to dig the prop out of the dirt. Spilled milk.

SO if using mixed voltages with an eagle tree system and you want to monitor throttle position, ONLY PULL THE SIGNAL WIRE!! :-)

Other changes at this time was to put the 5.8 TX antenna out behind the canopy in a more upright position for a better pattern and less of an opportunity for my video RX to be in the nulls.

So this bird is wingloaded, I'm not really sure at what, but it does feel more solid in the breeze than the old PZ T-28. I do think I need to add a touch more expo in the ailerons so that I'm not bumping it around so much correcting. I'm still perfecting the handlaunch and I was thankful for the 5-7 knots that graced me today. I also noticed how low my amp draw was and while getting a 15 minute flight was rad, and full throttle rewarded me with 60 MPH ground speed passes, I think I might prop this sucker up with a master airscrew 10x7x3. I think the current one is a 9x6x3. I'll check that schmick out before making the purchase, but I do have plenty of headroom on my ESC.

Here are a couple of snapshots and a video. The video is unedited 15 minutes of buzzing around. You've been warned. Also N.B. that I have not hooked up the pitot tube for the ET and that the altimeter is the barometric kind and that obviously the throttle position indicator was disabled for this flight. Fun times!

I've also been mulling over adding an instrument panel of some sort and fixing up the canopy to be a bit more rigid and look a little more realistic. And maybe painting the thing up to some non-military scheme. We'll see.

Dynam 1200 Spitfire FPV, Eagle Tree (15 min 18 sec)
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Old Jan 11, 2012, 01:46 PM
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More progress, I hooked up the pitot tube via one of the places for a decorative rifle. Since the retracts are not in, there was bountiful space for the tubes out of the back. I bench tested and wasn't getting any prop wash on the tube so it should get a decent reading on the airspeed.

I also popped the power wires out of the throttle y-cable provided by eagle tree. My throttle position is now working EXCEPT after multiple attempts to calibrate it WILL NOT drop to 0. It bottoms out at 24-25 but goes up to 100. Whatever. Also my RSSI is 100+ whatever the value is. So 200 is max signal, 100 is no signal. Whatever.

I also made some other airframe modifications, namely making a functional scoop since there was zero airflow going through there before. This will be venting the castle cremations ESC, BEC and the first thing after that to get the airflow is the current sensor for the eagle tree. Should work out nice because on a cool day it was a little toasty in there. I had to also make some exit holes out of the bottom. I decided to move the TSLRS NR antenna to a better orientation for distance.
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Old Jan 11, 2012, 05:32 PM
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Old Jan 12, 2012, 02:33 AM
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Old Jan 13, 2012, 01:35 PM
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Old Jan 13, 2012, 02:58 PM
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Aussie, thanks for dropping in!

So Yes I'm using a UHF control system, but the receiver is the "Normal Range" style, which is light weight and compact and has a short antenna and still impeccable range. It really isn't that big and for peace of mind, I'm ok with not losing control of my plane

In my opinion the Eagle Tree stuff is a little more on the overkill side. But I figured if I was going to put it in there, may as well deck it out.

So I've got circularly polarized antennas on it, right now I've got a clover leaf on the plane and a turbine from truerc.net on the ground. I just got done building a pan and tilt tracking station last night, so I'm about to embark on the nightmare of configuring it today. It has eagle eyes, my junk SD recorder, one 5.8 rx with a turbine on it and one 5.8 9 turn helix (also from truerc.net) on the tilt of the pan and tilt. All of this will get juice from one 3S battery that I've got laying around.

I need to snap some pictures, maybe I'll go on and do that now. I was mulling over going to a 2 blade prop, just need to find a spinner that will work (because the spitty just looks so good with a spinner!)

Very good advice on the ROG takeoff in your spit. I'll be applying that more when I'm back into a plane that has gears. I think it will be a 1400mm T-28, tricycle gear seems like an easier way to go and the PZ T-28 was so much fun to do touch and gos with. Some of the problems I found with ROG takeoffs was how bumpy it was and how that would impair visibility through the camera. I'm hoping a bigger plane with maybe some better struts and/or wheels might make that better.
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Old Jan 13, 2012, 05:02 PM
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Quote:
Originally Posted by pr0ject42 View Post
Aussie, thanks for dropping in!

So Yes I'm using a UHF control system, but the receiver is the "Normal Range" style, which is light weight and compact and has a short antenna and still impeccable range. It really isn't that big and for peace of mind, I'm ok with not losing control of my plane

In my opinion the Eagle Tree stuff is a little more on the overkill side. But I figured if I was going to put it in there, may as well deck it out.

So I've got circularly polarized antennas on it, right now I've got a clover leaf on the plane and a turbine from truerc.net on the ground. I just got done building a pan and tilt tracking station last night, so I'm about to embark on the nightmare of configuring it today. It has eagle eyes, my junk SD recorder, one 5.8 rx with a turbine on it and one 5.8 9 turn helix (also from truerc.net) on the tilt of the pan and tilt. All of this will get juice from one 3S battery that I've got laying around.

I need to snap some pictures, maybe I'll go on and do that now. I was mulling over going to a 2 blade prop, just need to find a spinner that will work (because the spitty just looks so good with a spinner!)

Very good advice on the ROG takeoff in your spit. I'll be applying that more when I'm back into a plane that has gears. I think it will be a 1400mm T-28, tricycle gear seems like an easier way to go and the PZ T-28 was so much fun to do touch and gos with. Some of the problems I found with ROG takeoffs was how bumpy it was and how that would impair visibility through the camera. I'm hoping a bigger plane with maybe some better struts and/or wheels might make that better.
TBH i seldom fly my undercarriage birds anymore, i've moved house and there are no paved or manicured airstrips around here, so only my handlaunched birds get a fly lately
i've been invited to warwick and soon rathdowny, both paved, but for the 1.5-2 hour drive to get there lol but it will be great to fpv off paved surface rather than risking damage the retracts every time i try on grass.
the exception of course- my 2 tail dragging ROG almost anywhere cessna's

my TS Cess will have FY21/AP, Dragon UHF, 1.2/500 vid, WDR600 cam
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Old Jan 25, 2012, 12:29 PM
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Originally Posted by AussieHoppy View Post
my TS Cess will have FY21/AP, Dragon UHF, 1.2/500 vid, WDR600 cam
Dood, this wasn't the same plane that just smoked itself in, is it? I saw that video and I'm guilty of doing the same, something doesn't quite feel right but I just say "F it!" and end up regretting it.

So the good news is that the pitot tube works well, all of the other eagle tree stuff I hooked up is working as I had expected, including antenna tracking which is a pretty cool bonus. A bummer is that now I've got my recorder hooked up to the same lipo that the rest of my ground station is hooked up to, I'm getting lines in the video. I'll have to put a filter on the power feed for it, I reckon.

I'm thinking about using this plane to throw my hat in the ring for the mile out and back speed contest that CaliDave is pitching. So my plan is the 10.5x9 PZ extra prop, new spinner and I just got some new 4S turnigy batteries that have a higher discharge rate than the other battery I've been using. With the current standings and my current setup, I could be in the top 10 (a bixler being one of those planes) but I would like to be somewhere in the top 5. I'm pretty sure I'm not going to beat the number one slot at 1:25 for the round trip. Yeah two miles in 1:25 including launch and landing.

Aussy, you should hook up that competition, your Jug could put up some decent numbers!

At any rate preliminary tests happen today with new prop, we'll see what it nets me, if I don't smoke it into the ground on launch.
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Old Jan 25, 2012, 12:38 PM
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Mile out and back ... Go for it
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Old Jan 26, 2012, 10:08 AM
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Well I tried out the PZ prop with new spinner.

A couple of things if you're going to do this:

You need a 2.5" spinner

The Dubro one sat a little deep and was rubbing the foam of the plane so I had to manually hold the backplate of the spinner while I tightened the prop down to space it out. We will see how this works out in the long run.

My amp draw jumped from in the teens to in the 30s with this prop. You have been warned.

GPS speeds surged to the 70s. Airspeed according to the eagle tree didn't see as much improvement just getting to the 60s, but I didn't have much of a delta in my ground speeds going in any direction so I am ruling out winds aloft altering my GPS speed. I think there is a restriction in the pressure lines to my pitot tube.

Holy cow this plane likes to go fast! I didn't bust out any high G maneuvers because I'd like to keep this airframe in one piece for a bit longer. But it would just lock in the faster it went. Need to fab up a windshield for my cockpit.

Hand launch went a little bit better with the two blade prop. Not sure if this is due to the lessened torque effect of the two blader or if the increased pitch allowed it to gain airspeed more quickly making the wings more effective or what.

Of course I'd love to show some video, but my lame ground recorder corrupted the AVI file. I hate that thing and need to find a replacement because this isn't the first time I've lost footage due to it not being able to close out a file correctly.

As a final note, I also picked up an APC 10x10. I lose .5" in diameter but pick up a full inch in pitch. This might be just what the doctor ordered!

Now.. to figure out how to slow it down... I could try flaps but I really think I need speed brakes more than flaps. Maybe like a crow setup like some gliders use? Has anyone set up a crowing mix on a futaba? Can I maintain some aileron control while in a crow? I have no rudder on this rocket (see rookie move as depicted in first post) so I would need to keep some ability to steer.
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Old Jan 26, 2012, 01:32 PM
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Bummer, 10x10 doesn't fit into the spinner without some grinding. Maybe I will have some time for that tonight.

EDIT: Funk dat. The clearance wasn't very close. Back to the LHS and picked up a hangar 9 2.5" spinner (bright orange, no less) and it only took a bit of notching to fit the apc 10x10. Flight test to come this afternoon me thinks.

I attempted a high speed landing yesterday in the mile and back style. Didn't fare so well. Snapped a blade off of my prop (another good reason to return to the LHS) and it skipped a couple of times. There isn't any happy green grass where I'd like to attempt this so either a smoking pavement landing (which was what I attempted) or landing in scrub which might cause cartwheeling and major damage. So I'm trying to figure out a way to slow it down quickly. We'll see how it goes.
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Old Jan 30, 2012, 04:02 PM
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Bummer.. looks like the 10x10 was not enough get up and go on a no wind, no running launch day.

It is repairable.. the PZ prop did work really well..
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Old Mar 27, 2012, 10:17 AM
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I guess it is time for some updates. So after I smoked it into the ground I had the opportunity to do some re-vamping of the power system, considering the nose was broken off and split in half and I bent my motor shaft.

I found a pretty good bit of lead in the nose, tucked away in a compartment, so I thought maybe I should remove the lead and replace it with lipo and motor. So I grabbed a 5S battery that I've got sitting around and started looking at what it would take to weasel that sucker into the nose of this plane. Well not much trimming, although I wouldn't have wanted to do it while the plane was intact.

Then I went on this long LONG search to find the motor/mount size combo that could handle 5S and still fit in the nose of this plane without looking odd.

Finally I found this:
A 4240 600kv motor

I mated it with a himax motor mount that matched the holes on the stock plate and had the right pattern for the motor. I did have a problem though, as the motor diameter was too large for me to screw in the x-plate into the firewall, so I had to drill 4 small holes in the plate, set the screws into the mount that were to bolt the motor to the x-mount and then screw in the x-plate to the firewall, then poke an allen wrench through the holes I drilled into the firewall and fasten the motor to the x-mount second. The short answer is there is no way you are doing this mod without removing the firewall from the plane.

As a result I've got a big fat motor sitting up front. I mated it up to a hobbyking 90/100 amp ESC, an overkill western robotics BEC to help power the eagle tree stuff, and added a power converter from dpcav to run the tx and camera. I need to put a filter on that, I was getting some motor noise in my video, but more on the video later.

I went back to the old eagle tree gear, except this time I installed and configured the guardian, I updated the eagle firmware for PPM sum input to reduce some of the spaghetti mess, but the rest really remained the same. I used the same dubro spinner and parkzone extra 300 prop, both of which fit the shaft of the motor perfectly. I did have to trim the nose down a little bit as the spinner was sitting on foam, ever so slightly.
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Old Mar 27, 2012, 10:21 AM
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I this morning I went out to re-maiden. I'm glad I had the guardian in there, as I lost video with it about 300 yards away and some how I managed to not only land it safely, but land it right in front of myself, having to only stroll 5 feet to pick it up.

Also, unbelievably I think it is a touch tail heavy. The guardian was acting all funky in flight, I need to read up on how to tune that thing. Between all of that, the fact that I didn't have the right 5.8 channel on my ground station thus no flight recording and mercifully I snapped the prop on a bad launch, I came home with an intact airframe.

I do know that mid throttle was upper 50s, it would seem to lock in as I eased further into the throttle, but right about then my video blacked out so I didn't get a chance to check speed.

So I've got a number of things to straighten out, but I think this bird is going to be a lot of fun once I get the bugs straightened out! When I killed the throttle, she wanted to just float on in with a nice glide path, really crazy how docile it was when it was being flown that way. The stabilizer may have had much to do with that.

At any rate, there it is. This plane is fun!
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