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Old Nov 11, 2014, 12:19 PM
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USA, CA, El Dorado Hills
Joined Apr 2008
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You may be on to something. I am used to flying very fast planes and it does feel slow but I normally gauge it by how much elevator I have to use to see if I'm flying too slow.

So a couple of things I needed to add to the flight.

1. I was flying from a GA runway in Lodi at a Jet Event. Not knowing if the flaps would affect the pitch, I took off without them. Took a lot of runway...700 feet maybe?

2. When it broke ground I was pulling a good bit of elevator and as normal, I would release some back pressure after take off to have a nice steady climb. It instead dove to the ground and bounced a bit, but I didn't think it was that bad. I didn't know it at the time but the gear mounts broke. Looking at the damage later it was clear the plywood mounts were not glued to anything but the skin.

3. Okay so I'm up in the air, pulling 3/4 elevator to keep it level and full throttle. Normally I would think it was nose heavy...so I keep on the throttle to keep it in the air. I got some help adjusting the trims and eventually got it flying a bit better. But it won't climb very well.

4. The whole flight I left the gear down just in case so I have a fair amount of drag. And to make it worse when I landed I found one of the cowl doors got blown open during flight and ripped in half. Argh!!! So I had a bit of drag for sure.

5. Came in for a landing, greased it nicely and it just settled on the broken gear no problem.

So I have some repair to be done and need a new left cowl.

My thoughts are:
a. I could lose some weight with the RX batteries. I'm using 2 x LiFE 4000 mah batteries. What are others using.

b. Take off with flaps.

c. I need to check my elevator throws. Anyone have a close up picture of neutral and full up elevator with a reference to some other part on the plane? It is possible I was flying with a slight nose down neutral setting.

d. Maybe adjust the CG back some. I set it as specified in the manual...but moving back a little can't hurt.
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Old Nov 11, 2014, 12:37 PM
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birdseed's Avatar
sussex England
Joined Jun 2002
474 Posts
I'll get a photo of the neutral point later, but it's just above the light blister. I needed 35mm up elevator and used it all to rotate, then hold it until I'm at least 100ft in the air.
I used the CG stated earlier in the thread, on the previous page.

(Think I posted the result of my first flight on a previous page-sounds like your maiden was as exciting as mine)

I managed to rip a gear out on landing too, and again the mount was attached to skin and not much else. I've since reinforced it with a plywood box. I fully expect to have to the other wing at a later date.

Don't get downtrodden though, it's a beast in the air.
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Old Nov 11, 2014, 12:58 PM
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St. Mary, Maryland, United States
Joined Dec 1996
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So, those readings are off the Castle ESC's? If so a few thoughts:

I seem to remember lot's of folks commenting that the Castle logging always read HIGH on amps.

YET, you are only showing 3,500 watts per fan which is LOW. A 10S EVF is normally at least 4,000 watts if not 4,400. Of course your batteries are forward and your fans rearward, hope you are not using 12 gauge wire for the harness? Even with 10 you might make an 8 gauge test harness of the same length and test both statically on the ground.

General A-10 handling characteristics - I had my own scratch built A-10 about a decade ago, 2 90mm Shubies @ about 16 pounds RTF and 3,500 watts. The plane had MASSIVE power, especially for the time. However, it was quirky. With the massive thrust above the airframes centerline there was a lot of trim change from power on to power off. Yes, the ground run was longer than you would think due to the moment arm on the fans pushing the nose down which needed quite significant airspeed to be able to rotate. Full throttle level needed LOT's of up trim. Yet, if you chopped the throttle it would float like a glider.
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Old Nov 11, 2014, 08:19 PM
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Brentwood, California
Joined Jul 2007
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Hey Shawn,
sorry to hear you didn't have the power you hoped for....
castle logs always read high, I'd do a ground check with an clamp meter if you can.

But if they are reading high you only have like 3000 watts per fan at 6000 watts total you must be pretty close to 40 pounds as thats where others have come in. Your only getting 150 watts per pound... you need more power even if your 35 pounds that still only 171 wpp. I like to see 250 for a scale jet or more.... with a sport jet you can get away with less but not a draggy warbird.

Are your leads long? I remember the giant me 262 with vio fans that was having power issues.... maybe you can choke down your tail pipes?

Lots of good fan combos you can do... but those vio fans should do the trick. Maybe 10's isn't going to cut it with this bird?
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Old Nov 12, 2014, 07:13 PM
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birdseed's Avatar
sussex England
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Hope Didier doesn't mind me copying his photo here, this is the neutral point of the elevators. I copied his and mine only needs a couple of clicks of up trim to fly level.

I set my travel for 35mm of up elevator, 25mm of down.
Once airborne I reduce to a lower rate of 25mm up and down, as per the instructions. I haven't tried to get airborne with 25mm of travel yet.

With 20mm of flap it's airborne in around 60-70 yds of Tarmac.

Flap and gear down needs some more up trim but nothing excessive.
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Old Nov 13, 2014, 06:21 PM
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Leopoldsburg, Belgium
Joined Jul 2006
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Quote:
Originally Posted by birdseed View Post
Hope Didier doesn't mind me copying his photo here, this is the neutral point of the elevators. I copied his and mine only needs a couple of clicks of up trim to fly level.

I set my travel for 35mm of up elevator, 25mm of down.
Once airborne I reduce to a lower rate of 25mm up and down, as per the instructions. I haven't tried to get airborne with 25mm of travel yet.

With 20mm of flap it's airborne in around 60-70 yds of Tarmac.

Flap and gear down needs some more up trim but nothing excessive.
Nope, i don't mind at all

Didier
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Old Feb 08, 2015, 10:30 PM
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icicles's Avatar
Australia, ACT, Canberra
Joined Jul 2006
646 Posts
Hey Guys,
Just an update, my A10 i slowly getting there. My 120mm Stumax's should be here shortly.
And i have managed to shoe horn in 4 x 6s 5500mah cells for each fan. So that's 12s 11,000mah per side. It was tight but i got them in.
I'm going to be trying Blend 427 70c Revolectrix cells this time. So it will be interesting to see how we go.

Chris
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Old Mar 04, 2015, 12:38 AM
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San Diego
Joined Jul 2009
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Quote:
Originally Posted by icicles View Post
Hey Guys,
Just an update, my A10 i slowly getting there. My 120mm Stumax's should be here shortly.
And i have managed to shoe horn in 4 x 6s 5500mah cells for each fan. So that's 12s 11,000mah per side. It was tight but i got them in.
I'm going to be trying Blend 427 70c Revolectrix cells this time. So it will be interesting to see how we go.

Chris
Chris,

Did you order it from skymaster to fit the 120 fans? It looks like most guys are using 128's, just wondering if skymaster has a 120 nacelle option??
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Old Mar 04, 2015, 02:29 AM
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Australia, ACT, Canberra
Joined Jul 2006
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No, just placed my order. I have to make my own inlet reducers. And tail pipes for that matter. No real big problem though.
120mm fans should be more than enough omph. I've had awesome success with all my Stumax fans ☺
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Old Mar 22, 2015, 10:09 PM
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Australia, ACT, Canberra
Joined Jul 2006
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Just a quick update
Ran my first 120mm Stumax up.
Wow.
Like this fan very much
Very nice indeed, super smooth
Some figures
After 45 seconds of full power, fresh off the charger
48.3 volts (yes I know it sounds high, measured with aFluke)
120 amps
5796 watts in
Exhaust outlet diameter 105mm
Thrust, don't know as yet, didn't have enough hands lol

Slowly getting there. Still have a fair bit to do

Chris
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Old Mar 23, 2015, 12:16 AM
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San Diego
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Glad to hear you are making progress!! I ordered mine last week, had Tam build up the Dynamax's and they should be here tomorrow! I was bummed to find out that they are only offering 3 schemes for regular orders and anything other than those schemes is a 6 month wait!! I wanted the same as Wes's but with the tiger shark mouth which they offer on their big A-10 but they claim that's custom so I just went with the arctic AK scheme hopefully it will not be an issue....

Not sure which motors I am going to run but will do some testing before it arrives!!
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Old Mar 23, 2015, 06:30 AM
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Australia, ACT, Canberra
Joined Jul 2006
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You'll be fine with Tam's Dynamax. He does an excellent conversion. Can't go wrong.
I must admit I did have to wait for a while for my A10 to show. More than happy with the model. When they say ARF, I think they should really say 5%done 95% for you to do. Good luck with the build

Chris
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Old Mar 23, 2015, 08:42 AM
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San Diego
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Yep I already have a couple of his conversions in some other jets and really like them, the spinner gives it a cool scale look. I'm familiar with the "ARF" labeling and figured as much.... I'm building a big a Skymaster F/A 18 Superhornet with a 210 turbine in it and it has been allot of work....

One thing I am planning is to mold up some nice thrust tubes, similar to what BVM did. I can see that others have definitely felt the negative thrust issue but some proper thrust tubes will solve it..
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Old Mar 23, 2015, 05:05 PM
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Australia, ACT, Canberra
Joined Jul 2006
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These are my inlets. I will be modifying my thrust tubes as i am not totally happy with them. The Stumax is a long way back, one being light and two i have a lot of batteries to balance

Chris
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Old Mar 26, 2015, 10:12 AM
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San Diego
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Looks good Chris!! So I am not super happy about the communication with Skymaster... It has taken a lot of back and forth to figure out I could not order the scheme I wanted and apparently it is a back up in their paint dept.. So I decided to go white gelcote and paint myself to save time, plus I am not crazy about the 3 schemes they are offering for normal delivery time right now.. I have not heard back from them since last week, I just want to get confirmation that it's in process.. Hope to confirm today!! Ready for some Warthog time!!!!
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