SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jul 21, 2009, 06:29 PM
Registered User
Lynn Haven, FL
Joined Jul 2008
34 Posts
Quote:
Originally Posted by NJNJperson
The manual is excellent. It provides detailed flight information that is very helpful. In retrospect, coming from EPP 3-D planes, I'm a complete noob at balsa 3-d planes. For ex: "huh? I have to let off the throttle on the down leg of a loop?" You mean I can't do full throttle snap rolls?

Left unchecked and without club advice, this generation of 3-D foam park flying trainers can really reinforce some bad habits.

The biggest revelation for me was this statement in the manual:

"..straight and level flight should be at a reduced throttle and full power should be used only when the airplane is “loaded” during a maneuver."
And the manual is correct on this one! At the speeds this thing will achieve at full throttle, an aggressive "yank" with the 3D settings could be disastrous. I'm still taking it easy on mine, and haven't ventured to the 3D throws yet. Nowhere near ready for that yet!
stuhrw is offline Find More Posts by stuhrw
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 24, 2009, 10:30 AM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
16,446 Posts
That takes all the fun out of a tumble doesnt it? (Full speed yank all stick and watch it pinwheel)
losifanatic is offline Find More Posts by losifanatic
Reply With Quote
Old Jul 24, 2009, 11:28 AM
Registered User
Joined Aug 2006
227 Posts
Quote:
Originally Posted by losifanatic
That takes all the fun out of a tumble doesnt it? (Full speed yank all stick and watch it pinwheel)
See...that's what I thought too. I think perhaps that with 330W under the hood of a 40" plane, throttle management skills are the order of the day, especially with the size of the control surfaces.
NJNJperson is offline Find More Posts by NJNJperson
Reply With Quote
Old Jul 24, 2009, 11:56 AM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
16,446 Posts
I have another 29oz 40inch 3d plane and I have 370 watts under the hood and do full throttle tumbles and blenders all day. All though throttle managment is in order for ALL 3d planes. It is nice to be able to do some full throttle sillyness. I injoy Knife edge spins, tumbles, walls ,and blenders. The hard on the airframe stuff.
I had issues with durabilaty with the great planes reactor bipe and was wondering if they increased streangth on this one?
losifanatic is offline Find More Posts by losifanatic
Reply With Quote
Old Jul 27, 2009, 11:43 AM
Registered User
Joined Aug 2006
227 Posts
[QUOTE=losifanatic]I have another 29oz 40inch 3d plane and I have 370 watts under the hood and do full throttle tumbles and blenders all day. /QUOTE]

what are the mfg & model of your 29oz 40" plane?
NJNJperson is offline Find More Posts by NJNJperson
Reply With Quote
Old Jul 27, 2009, 12:26 PM
Paper Crafter
Crackskull's Avatar
Joined Apr 2009
85 Posts
My guess is he has a 3dhobbyshop.com 40" Edge 540 with either a reaper-25 or omega72g motor.

It's a perfect plane.
Crackskull is offline Find More Posts by Crackskull
Reply With Quote
Old Jul 27, 2009, 01:09 PM
Registered User
Joined Aug 2006
227 Posts
Quote:
Originally Posted by Crackskull
My guess is he has a 3dhobbyshop.com 40" Edge 540 with either a reaper-25 or omega72g motor.

It's a perfect plane.
which brings up an interesting point. The Great Planes box states "carbon fiber" and there is CF in a few spots (bottom side of fuselage from the firewall back and some flat CF spar reinforcing the balsa spars), but nothing like the elaborate CF all over the 3dhobbyshop stuff.
NJNJperson is offline Find More Posts by NJNJperson
Reply With Quote
Old Jul 27, 2009, 01:23 PM
Paper Crafter
Crackskull's Avatar
Joined Apr 2009
85 Posts
Quote:
Originally Posted by NJNJperson
which brings up an interesting point. The Great Planes box states "carbon fiber" and there is CF in a few spots (bottom side of fuselage from the firewall back and some flat CF spar reinforcing the balsa spars), but nothing like the elaborate CF all over the 3dhobbyshop stuff.
3dhs only puts cf on the wing tubes and landing gear but the plywood is thicker than gp and the overall design makes for very rugged planes. It Presission arobatics that laminates the wood with cf. But you also pay allot more $$$ for those airframes compared to the gp offerings. Personally I think the extra cost is worth it.
Crackskull is offline Find More Posts by Crackskull
Reply With Quote
Old Jul 27, 2009, 04:50 PM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
16,446 Posts
[QUOTE=NJNJperson]
Quote:
Originally Posted by losifanatic
I have another 29oz 40inch 3d plane and I have 370 watts under the hood and do full throttle tumbles and blenders all day. /QUOTE]

what are the mfg & model of your 29oz 40" plane?

3d hobbyshops edge 540. Mine is heavy at 29oz and has taken dropps from 6feet up staght on the nose and I just went up and fliped it over and flew off. I have beeten the crap out of that plane and its rock solid and a 3d monster!
losifanatic is offline Find More Posts by losifanatic
Reply With Quote
Old Aug 07, 2009, 12:59 PM
CSI
I promise, just ONE more order
CSI's Avatar
Del Rio Intl, Texas, United States
Joined Feb 2004
3,983 Posts
Just an update: I have several flight on mine now and it is an excellent flying machine! I have thoroughly enjoyed flying this SU! It flies extremely stable, the nose seems to stick on any direction I point it to. I have had no structural isses to date with moderate to heavy control deflections. I just put a piece of clear tape across the top of the cowl-fuselage joint and the cowl has not moved. It's only a 3 inch strip of scotch tape, but works great.

My .40 Dubro tailwheel assembly makes ground ops/taxi a delight.
The Rimfire motor works great, but not quite unlimited vertical performance. It goes straight up for quite a while, but finally does top out...it's a small speck by then anyway?!

Anyway...I'm quite happy with mine....
Ken
CSI is offline Find More Posts by CSI
RCG Plus Member
Reply With Quote
Old Aug 13, 2009, 08:53 AM
Registered User
Joined Aug 2006
227 Posts
anti-rotation pins

Just a word of caution on the build. Be sure to set the anti-rotation pins in the wings with some attention to detail and final alignment of both wings with each other and the fuselage.

I went through 10 packs of frustrating shakedown flights that displayed an odd clockwise twists during even gentle maneuvers (yes everything is true and aligned, tail-wing-rudder, and trimmed for level flight). I finally noticed that there was just about a 0.8 deg of difference in AOA between the left and right wings. I tracked the problem down to the way the anti-rotation pin was glued into the wing. On one wing the pin had set with a slight angle causing the 0.8 deg difference.

I repositioned the pin with a routine of CA Uncure applications. I set the dang thing again and now both wings are dead on aligned. Hopefully weather holds up today for a test flight.
NJNJperson is offline Find More Posts by NJNJperson
Reply With Quote
Old Aug 14, 2009, 06:03 PM
Registered User
Joined Sep 2006
588 Posts
Weight and balance issues

Has anyone weighed their SU-31 yet? Mine came in about 10% overweight; no small factor was the fact that I had to add nearly 2 oz in the nose to get the cg forward to the recommended position. This was in spite of the fact that I had already added a larger motor and esc. Anyone else had this problem?
bob93447 is offline Find More Posts by bob93447
Reply With Quote
Old Aug 15, 2009, 05:54 PM
Huckfest or bust!
cryhavoc38's Avatar
United States, WA, Woodinville
Joined Mar 2007
8,057 Posts
Quote:
Originally Posted by NJNJperson
=HS-55 Ailerons - DON'T=
With this being my first 300W 3-D Balsa, I didn't know any better and put trusty new HS-55s. HS-55 worked great for my other five planes. On my second flight, I put it into a full throttle positive cross-snap (up elevator, aileron rudder opposite). At that point I heard a major mechanical groan echo through the fuselage. I brought it down for an inspection. It turns out that I stripped both HS-55 servos on the ailerons.

I had the ailerons set to 3-D throws, so HS-55s on smaller throws might be fine. I had mine positioned at the 2nd most aggressive point on the control horn to achieve the recommended 3-D throw.

I'll be studying the Hitec servo chart to find the equivalent Karbonite or metal gear HS-55.
Good ol trusty HXT900's from hobbycity have more torque and speed than the HS-55's and at less than $4 per servo, they are truly the best inexpensive parkflyer servo out there.

Just finished my Electrifly SU-31 with hxt900's all around.
I put in the Super Tiger .10 brushless.
At $23.99 this is a great little motor.

1250KV
320 Constant watts
370 watts burst
69 grams
29 amps constant
33 amps max burst
cryhavoc38 is offline Find More Posts by cryhavoc38
Reply With Quote
Old Aug 15, 2009, 09:12 PM
Registered User
Joined Aug 2006
227 Posts
Basic loops?

Anybody else have trouble doing a clean loop with this plane? At some point during the loop the SU-31 abruptly twists out of the maneuver with a clockwise roll and right skid (at least that's what I think is happening). Countering with left aileron and a bit of rudder cleans up the loop somewhat, but this is the first airplane I've ever had that does this.

I've checked and verified lateral balance, CG, left & right AOA. Wing and tail are square from both top view measurement and rear view eyeballing.

I've also noticed that at some point in a constant radius turn (with more up-elevator input of course), the plane again unexpectedly rolls right again requiring left correction. Constant radius turns with slight elevator don't have this happen so much which leads me to believe it's the halves of the elevator flexing differently. However, the elevator joiner seems pretty stout, so I find it hard to believe it's flexing under such a light load.

Some asymmetries on plane that I've measured, but I don't think they're responsible for this behavior:

1. The left wing is 1/16 inch shorter than the right wing
2. The gap between the aileron & body is 6mm on the left wing and 7mm on the right

Can any body share an expert opinion on this?
NJNJperson is offline Find More Posts by NJNJperson
Reply With Quote
Old Aug 16, 2009, 01:02 PM
CSI
I promise, just ONE more order
CSI's Avatar
Del Rio Intl, Texas, United States
Joined Feb 2004
3,983 Posts
NJ,
Sorry to hear you are have some snap problems. I don't have any problems with mine...loops track beautifully, nice solid turns...

I am guessing you still have too much elevator throw. I had to tone mine down a good bit. The design has such short wing/tail coupling that it is going to be very sensitive to CG settings and pitch control.
Notice pattern planes have those real long fuselages where the rudder/elevators are wayyyyy back there? These SU's are close to how a biplane is setup...short tail coupling.

This short tail is going to make CG settings very sensitive and just a slight change will make a huge difference. Same for the elevator throws. Just a bit too much and, with that short couple, the wing is going to be very sensitive to snapping and/or tip stalling. There is always going to be some slight difference between the wings...shape, dihedral, twist, incidence, etc, so very common for one to stall slightly ahead of the other.
All of this combined is making the wings prone to snapping out, one wing accelerated stall, causing violent roll.
I have seen this on so many planes in the past. Almost always too much elevator throw, and/or aft cg.
The problem can be helped with moving the cg forward slightly, reducing the elevator throw, etc, BUT,...unfortunately, may never go away entirely. It's not usually a speed issue either.
I have seen some help achieved through adding in some wingtip washout. Either heating up the outer wing area and warping the trailing edges up just a slight bit, or sometimes slightly raising the ailerons.

This is all I know based on my own experiences and also from many others who had similar problems.
I hope you can get it tamed down.
On mine, I had to add about 2oz of lead to the nose...a bit more than I would like, but it made the tracking solid.
Good luck NJ,
Ken
CSI is offline Find More Posts by CSI
RCG Plus Member
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Article Great Planes Edge 540T E-Performance Series 3D EP ARF 50" Review Bajora 3D Flying 173 Jun 29, 2014 07:51 PM
New Product Great Planes SU-31 E-Performance Series 3D EP ARF summerwind 3D Flying 45 Jun 21, 2009 10:46 PM
For Sale Great Planes Ultimate Bipe E-Performance EP 3D ARF rongreg13 Aircraft - Electric - Airplanes (FS/W) 0 Jan 10, 2009 12:03 PM
New Product Great Planes Ultimate Bipe E-Performance EP 3D ARF 33.5 hamman 3D Flying 13 May 03, 2007 08:08 AM