HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 11, 2014, 01:19 PM
Registered User
sbritton's Avatar
USA, CA, El Dorado Hills
Joined Apr 2008
1,018 Posts
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.
sbritton is offline Find More Posts by sbritton
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 11, 2014, 01:37 PM
Registered User
birdseed's Avatar
sussex England
Joined Jun 2002
466 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.
birdseed is offline Find More Posts by birdseed
Reply With Quote
Old Nov 11, 2014, 01:58 PM
Registered User
St. Mary, Maryland, United States
Joined Dec 1996
8,469 Posts
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.
Chris True is offline Find More Posts by Chris True
Reply With Quote
Old Nov 11, 2014, 09:19 PM
Pursuit of Happiness
Ron101's Avatar
Brentwood, California
Joined Jul 2007
7,254 Posts
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?
Ron101 is offline Find More Posts by Ron101
Reply With Quote
Old Nov 12, 2014, 08:13 PM
Registered User
birdseed's Avatar
sussex England
Joined Jun 2002
466 Posts
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.
birdseed is offline Find More Posts by birdseed
Reply With Quote
Old Nov 13, 2014, 07:21 PM
Registered User
Leopoldsburg, Belgium
Joined Jul 2006
226 Posts
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
didier n is offline Find More Posts by didier n
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Hacker A10-13L and X-7 Pro ESC Benf207 Aircraft - Electric - Power Systems (FS/W) 2 May 03, 2012 10:02 PM
For Sale Skyangel 35mm & 50mm EDF Jets F15 Mig29 A10 T45 JAS39 Mirage2000 **Free Shipping** www.hobbyb.com Aircraft - Fuel - Jets (FS/W) 0 Apr 29, 2012 01:51 PM
Wanted 1:8 / 1:7 RTF EDF Jet: CARF / TamJets / Yellow / BVM Alkaline Aircraft - Electric - Jets (FS/W) 6 Mar 16, 2012 02:59 PM
Sold Skymaster ARF PLUS EDF Viper Jet (1.6M) $1500 Shipped FlyBoyTha1 Aircraft - Electric - Jets (FS/W) 1 Oct 01, 2011 12:44 PM
Video A10 EDF Jet Rally Hodges Hobbies 7/24/09 JIMinKENTUCKY Fuel Plane Talk 1 Jul 29, 2009 10:17 AM