Thanks, Chris. I think I'll have to use the E prop with that motor, at least according to the APC specs on maximum RPM for the SF props.

I will certainly keep you posted and post some pics when my build is done. I got some more done today, but I'm a slow builder. I am making mine so all the servos are easily removable, so that's taking a bit of extra time.

I look forward to seeing your flight videos!

Neil

Another idea would be to use a Xoar wood E prop.

I'm just going to start out with the APC E prop and see if I have any issues with balancing the plane.

Neil

Just a few pictures of Neil's new SU 29 at Rancho this morning. Smooth, precise, and feels very light.

Ron

Major congrats, they look great together!

Thanks for posting those photos, Ron. A very productive maiden flight this morning. The big Sukhoi required very little trimming and was a real floater with the 70g 2830T/1095 Torque motor with an 11X5.5 prop and a 3S Gens Ace 1550 pack. There was no problem balancing the plane, and I had a wide range of possible CG choices to fool around with. I was very conservative with my flying because the battery was just velcro'd onto the side of the fuse and I didn't want to anything too violent. When I settle on the CG, I will cut a slot in the foam so the battery is well-secured. But it flew like the smaller RC Factory planes, only in slow motion -- a lot of time to think about what you were doing. I want to experiment some more before I settle on this power system. I think a slightly bigger motor (2818T/900 Torque, for example) might be a better fit. That would be 104g as opposed to 70g, but it seemed from today's flying that the airframe could handle a bit more weight.

Chris, can you tell me more specifically what power system you felt was too heavy and what you AUW was? Thanks.

Neil

Originally Posted by Neil Morse

Thanks for posting those photos, Ron. A very productive maiden flight this morning. The big Sukhoi required very little trimming and was a real floater with the 70g 2830T/1095 Torque motor with an 11X5.5 prop and a 3S Gens Ace 1550 pack. There was no problem balancing the plane, and I had a wide range of possible CG choices to fool around with. I was very conservative with my flying because the battery was just velcro'd onto the side of the fuse and I didn't want to anything too violent. When I settle on the CG, I will cut a slot in the foam so the battery is well-secured. But it flew like the smaller RC Factory planes, only in slow motion -- a lot of time to think about what you were doing. I want to experiment some more before I settle on this power system. I think a slightly bigger motor (2818T/900 Torque, for example) might be a better fit. That would be 104g as opposed to 70g, but it seemed from today's flying that the airframe could handle a bit more weight.

Chris, can you tell me more specifically what power system you felt was too heavy and what you AUW was? Thanks.

Neil

Neil I felt the 70 gram motors are the best bet. The 100 to 120 motors start to make the plane very bendy IMO.

Today I flew it with a 70 gram Motrolfly and an 1800 3s and it was pretty good. if I were to build it again I think I would put a tube int he fuse or ladder brace it in some way to reduce the twisting that the tail has.

--

For me this plane is the most fun to fly when it is light and floaty. it has very similar flight to some of the smaller profile Twited Hobbys birds on a light setup. For me the 3D performance of this plane starts to diminish when you get over 70 grams with the motor. The extra weight in the nose makes the tail more twisty.

In terms of which large Twisted Hobbys EPP planes to buy, I think the large RCF SU29 is good for a more floaty and relaxed setup and the Telink gear is more designed for higher performance and complexity. Not saying one is better than the other but different people would like each one.

We did a very quick vid:

Twisted Hobbys - RC Factory 1.2 Meter SU29 (2 min 29 sec)

Great video (as expected), Chris. Thanks for your insights. Next question: where are you balancing the model? I started at 125mm back of the LE (the recommended CG), but find that it pulls pretty hard to the gear in KE. My RC Factory Yak 55 has no coupling at all, so I was a bit disappointed. I tried moving it forward a bit, but still had significant coupling. Where do you have your CG, and what kind of elevator coupling are you experiencing? Thanks.

Neil

Neil, I balanced it in the air and ended up with the battery (1800) as far back as I could get it. I have not measured the CG yet. I found that that the coupling is more associated with the twist than the CG. Have you done any bracing yet?

In general terms though it is about half way between the spar and the aileron hinge for balance.

Thanks for the prompt answers!

Originally Posted by hercdriver7777

if I were to build it again I think I would put a tube in the fuse or ladder brace it in some way to reduce the twisting that the tail has.

Originally Posted by hercdriver7777

I found that that the coupling is more associated with the twist than the CG. Have you done any bracing yet?

I have not done any bracing yet, and I have to say that I find the model very "floppy" compared to the smaller RC Factory planes, which seem to be quite rigid and not require any bracing other than the stock CF rods. The larger size seems to make a difference. Have you done any bracing on yours, and if so, where did you do it? (I'm sorry to be asking so many questions, but the only 3D foamies I have built have been the smaller RC Factory planes, and I have just built them stock.)

Neil

No, I am in the same boat as you. The smaller RCF planes are very good and stiff. This larger one either needs a super lite setup or it needs some sort of bracing. I would inlay a square rod or a tube in the fuse if I had to do it again.

As promised, here are a few pics showing how I installed the aileron and rudder servos so that they can be swapped out easily in case of failure or stripped gears. The "plastic strips" used to secure the rudder servo are cut from old hotel "key cards." (I always save them since the material is useful for a lot of modeling applications.)

More pics showing the elevator servo installation and the guide for the push-pull elevator control rod. The instructions refer to a small (150mm) tube to use as a guide for the long CF control rod to keep the rod from flexing and eliminate slop. The tube didn't make it into the hardware pack, so I used a small length of cocktail straw that was just the right diameter.

I use the Dubro Micro Pull-pull kit for the rudder cables. I really like this set up since it is easy and makes an adjustable system so the cable tension can be adjusted if necessary. I use a wire loop (made from paper clip wire) at the rudder control horn end because I have found that the sharp edge of the fiberglass material of the control horn will eventually wear down the wire where it passes through the hole. With the wire loop, there is no sharp edge.

Great vid Chris