As cdee says, the pull-pull is more durable than it looks, however if you fly on cold or wet winter days in the UK, the cord does slacken off a bit. Once it has been back in the house for an hour or so, it is back to tension.

I built my SBach completely stock, the rods are fine in the wing, you don't need to substitute flat.

Mike

I used the CDee system with Golden rods and am I glad. I nosed my plane in a couple of days ago and bent the motor shaft. Absolutely no problem in taking the motor out and replacing it and I was off again.

The only mod I would look at in the future is the fixing of the servos. Very messy. I had to replace a bung rudder servo and it was a pain in he backside. Looks very messy now.

Good to know. I'll see what I can find to make it. This is my first try with a 39" aerofoil EPP. I want to improve my flying in places, and at heights, where my Visionaire would not be appropriate and without panicking all the time!

Originally Posted by GoAround

For the spar I have ordered some 1mm x 3mm carbon strips from Hobby King. My plan is to insert them in the same orientation as, say, a Crack Yak spar.

They will be less bendy than the supplied 1.5mm rods but I can't work out whether I should insert one each side or glue pairs together to make a pair of 2x3mm spars. I think one will do but has anybody tried it?

I didn't get an answer to this bit but figured that 3x1mm was going to bend a lot less than 1.5mm rod. This was confirmed when my HK delivery turned up. I understand how the two rods work but stiffer can only be better (!).

I spent a long time this morning (measure 200 times, cut once!) and put one strip either side, exactly opposite eachother and wicked in some thin CA. It has worked perfectly and the wing is super stiff. I actually used the full 750mm of the rods, rather than cut back to 670mm.

Once I buy some more 2 and 3mm drill bits, I can do the gear and progress on. I am still thinking of doing push rods, especially as I have two 670x1.5mm CF rods on the table

A question:

I have been reading the build of the newer Edge 540. Can anybody who has build both see any reason why I cannot sink my servos into pockets in the fuselage, in the same manner?

Likewise the motor mounting, any reason I couldn't rear mount the motor? This assumes I can get the parts I need ...

Originally Posted by GoAround

I didn't get an answer to this bit but figured that 3x1mm was going to bend a lot less than 1.5mm rod. This was confirmed when my HK delivery turned up. I understand how the two rods work but stiffer can only be better (!).

I spent a long time this morning (measure 200 times, cut once!) and put one strip either side, exactly opposite eachother and wicked in some thin CA. It has worked perfectly and the wing is super stiff. I actually used the full 750mm of the rods, rather than cut back to 670mm.

Once I buy some more 2 and 3mm drill bits, I can do the gear and progress on. I am still thinking of doing push rods, especially as I have two 670x1.5mm CF rods on the table

The wing spa definately needs uprating IMO. I have used single 6mm carbon tube, and its super stiff too. The weight gain is negligible. Its purely a cost that has been removed by adding cheap rods to the set.

Originally Posted by GoAround

A question:

I have been reading the build of the newer Edge 540. Can anybody who has build both see any reason why I cannot sink my servos into pockets in the fuselage, in the same manner?

Likewise the motor mounting, any reason I couldn't rear mount the motor? This assumes I can get the parts I need ...

You need to choose your mount carefully. I think unless you are not likely to crash (which you will if you are newb), then i wouldnt trust cocktail sticks. This model will take the additional weight of a better motor mount. I really cant recommend the one i have enough. I am so glad i did it, the front end is rock solid, and it has been smashed into the deck an number of times, with just a broken prop.

Originally Posted by jimbo320

You need to choose your mount carefully. I think unless you are not likely to crash (which you will if you are newb)

I am and I will!

What do you think of trying to replicate this, assuming I could get a mount for my motor? Photo stolen from 540 thread.



My alternative is just to replace toothpicks with 2mm carbon rod or try to fabricate something clever and removable like you and others have done.

Yes, that is the same as on the extravaganza. Just make the mount up out of ply. Is strong too.

I stoled the wooden mount from my 3d Buster to put on my sBach.
A slight mod but it works. Ill post pics asap.

There must be a trick that experience teaches and I have not learned it yet. Would someone be willing to share? How do you determine where to put the control horn when you don't have a hinge center line? In this case instead of a hinge you have flexing foam.

I think that unless the hole in the control horn is centered above the centerline of the hinge, servo travel versus flight surface travel is going to be affected.

This is not my first foam hinged plane where you don't actually hinge the surfaces. My past 2 builds I thought I got the hole of the control horn in the centerline of the imaginary foam hinge but once I began setting up my radio I could tell it was off a whole lot more than I thought it was. To get equal flight surface travel I was maxed out in the transmitter in one direction (and wished I had more) and limited in the transmitter in the other direction. I ended up with equal flight surface travel but total travel was limited, and I assumed it was because I didn't hit the control horn magic spot. IMO it is amazing how being off just a bit in control horn placement makes a large difference in surface travel.

Can someone please share your experiences or the trick to finding the sweet spot?

Just a bit of follow-up incase someone else ever asks a similar question

I never got any response so I moved ahead. In the end my results are the same as they have been for all my planes that have flexing foam hinges, thank goodness for computer radios .

My rudder control horn is spot on perfect, no need for any fancy radio "oops compensation". But then the rudder uses standard hinges.

But every other flight surface requires radio teaks to compensate for variation in control horn placement. Despite my best efforts everyone of them ended up in a bit different location with respect to hinge center point.

Originally Posted by DanWard

There must be a trick that experience teaches and I have not learned it yet. Would someone be willing to share? How do you determine where to put the control horn when you don't have a hinge center line? In this case instead of a hinge you have flexing foam.

I think that unless the hole in the control horn is centered above the centerline of the hinge, servo travel versus flight surface travel is going to be affected.

This is not my first foam hinged plane where you don't actually hinge the surfaces. My past 2 builds I thought I got the hole of the control horn in the centerline of the imaginary foam hinge but once I began setting up my radio I could tell it was off a whole lot more than I thought it was. To get equal flight surface travel I was maxed out in the transmitter in one direction (and wished I had more) and limited in the transmitter in the other direction. I ended up with equal flight surface travel but total travel was limited, and I assumed it was because I didn't hit the control horn magic spot. IMO it is amazing how being off just a bit in control horn placement makes a large difference in surface travel.

Can someone please share your experiences or the trick to finding the sweet spot?

I'm in the final throws of assembly at the moment

Has anybody flown it with and without the black SFGs? Almost seems a pity to put them on (the real one doesn't have them) so I was wondering how much real world difference they make.

Originally Posted by DanWard

Just a bit of follow-up incase someone else ever asks a similar question

I never got any response so I moved ahead. In the end my results are the same as they have been for all my planes that have flexing foam hinges, thank goodness for computer radios ...............

I can appreciate your desire for accuracy in the movement of control surfaces but in the instance of this particular plane I personally do not believe it warrants the attention. To me it's a foam throw in the back of the car and throw around the sky when you get a chance. If you attempt to have the accuracy required for an F3A machine it would be wasted time and money.

There are other areas which can affect the movement of control surfaces and you may be forever chasing your tail. How do you allow for things like the flexing of the servo mountings. Under aggressive flying the servos are going to move due to the flexing of the mastic holding them in place. I only use cheap servos which may not centre very well but are cheap to replace when I strip the gears crashing the plane doing things I would not attempt as close to the ground with my Sebart Sbach.

My Sbach is complete and has had it's maiden voyage

My differences from standard were:

1) Rear motor mount made from ply and blacked with a Sharpie. Like the Edge 540. Motor bolted to it which allows for thrust adjustment by washers.

2) Elevator and rudder by 1.5mm CF rod. Plastic clevis at the horn end, adjustable link at the servo and 3 supports made out of black servo horns. Works great and gives the recommended throws. The servos are quite well hidden as I copied the Edge 540 pics. I made a mistake and forgot what would happen when the elevator went up which lead to a rudder rod reroute and a small haircut for the elevator ....

3) Wing spars are 1x3x750mm CF strips. Now you see where the spare 1.5mm rods came from

4) Extra screws in the gear. Used the reinforcement circles unlike the photos above. I pre-made it on the plate as strong as possible then glued the whole thing on.

5) Some carbon strip (hidden) to reinforce the nose areas which looked weak after cutting a slot for the motor mount.

I have used a Purple Power 2831 with rear prop mount and some metal geared servos from 4-Max. 30A ESC and six 1000mAh 25C Zippy Compacts from HK. 10 x 4.7SF budget props. Orange RX615.

I took it for the maiden this morning. After a little battery moving for CG, I started to fly it and enjoy it. How sweet and co-ordinated. My ailerons only have about 30 degrees movement. I was going to extend the horns but, now I have seen the rapid roll rate, I won't bother!!

I was hoping to parachute it into the grass with no power. I even have a flight mode set with prop brake for this. Of course, it isn't really on so I settled for stalling it in as best I could.

Unfortunately, I had a panic and dumb thumb on battery 2. From a few feet up, inverted, I piled it in. The prop broke. I reached for the spare and then saw the rudder horn had torn out so that was that. Pretty sure the motor shaft or prop adapter is bent as there is vibration in the spinner. The carbon reinforcement stood up well and mud is the only evidence of the impact point.

Winds will be lighter tomorrow so I'll try all 6 batteries.

My brief go at slow flight showed just a trace of wing wobble so still not sure whether to attach the SFGs. Opinions sought.