Redshift F3F

[Peter Garsden]

Bit of a pause because I thought I had hit a brick wall. One of the control snakes which carries the 2mm carbon inner was attached a little too high up the fuselage which meant that it was very difficult to route it down the side of the ballast tube away from the wing joiner. I fiddled and fiddled.

In the end I took the wires and plugs out. I had used normal servo wire twisted. It wouldn't fit down the side of the tube and was protruding out the top. This meant that I couldn't route the snake on top down the side either. I changed all the wires for flat Futaba servo wire which works much better. James recommends this in the Schwing and I didn't think it was needed for the Redshift, but it works much better.

Here you can see the whole where the wires slide down into the bottom of the fuselage and under the ballast tube. Flat wire feeds a lot easier as it is stiffer. I marked the snakes right and left so as not to get them crossed.

This is how the snakes should fit, which took a lot of fiddling.

James advises that you make some pieces of packing to keep the snakes and the wires down by the wing joiner as otherwise they would protrude and foul it. I found some packing from a car liying around which is still enough but flexible and squashy enough. One slides this in over a steel ruler to keep the wires and snakes down. I did seal it with some hot glue.

[Peter Garsden]

When I said I sealed it with some hot glue, what I meant was where the snakes exit into the servo tray area, and down the sides of the snakes where they pass underneath the wing joiner so as to stop them riding up. This was only necessary on the one side where the snake is slightly too high up in the fuselage as I described.

[Peter Garsden]

Having now turned the corner of what I thought was a brick wall, I am on with the tailplanes

Doc recommends that one drills 5mm holes in the bottom of the fuselage, protecting the exit first of all with tape to stop chipping so as to take the carbon rod central tailplane supports. He then suggests filling the end of the hole with splooge of epoxy and filler, or fibreglass powder which is my solution

[Peter Garsden]

Doc also in his instructions shows how he finishes of connecting rods, which is a brilliant idea. I simply used to glue them with cyano to the carbon rods, but he suggests also gluing with epoxy, and shrinking on some tubing to finish them off - superb. One has, of course, to wipe off the excess with meths to give a smooth finish to the rod and stop it binding anywhere

[Peter Garsden]

I had a little mishap when fitting the tailplanes and trying to connect them up to the ball links. As I was trying to get them into position I heard a crack, and realised that one of the metal connector rods had come loose. I was somewhat surprised.

I was very impressed that this job has been done at manufacture as it is a bit of a fiddle.Whilst the job was very neat, the rod was only held in with glue, albeit 24 hour epoxy.

When I have done this myself, I have always put a 8mm bend into the end of the wire and inserted that into a 2mm hole in the tailplane trailing edge.

So I am going to dremmel out the glue, drill a hole, and re-attach it with epoxy and powder mix using a syringe, it being a narrow gap to access.

[James Hammond - Aeroic]

Pete - this is a serious mistake by my staff.

I apologise humbly for this, but I'm happy you brought it to light before flying.

Please check the other side too because if its like this one side, then the other side is likely to be the same bugger it!

The end should be bent at 90 degrees and glued into the elevator as well as along the hinge line.

Please email me if you need help on this.

Again my apologies - now I am going to the shop to boot someone's glutei!!!! (Or words to that effect)

Yaaahhh!

[Peter Garsden]

Thanks James, I must admit that I was a little concerned because the amount of torque these rods are subjected to is quite considerable, the rod being at the hinge line. I will certainly check the other side yes indeed.

I don't have a problem with this, as it is something I have done myself on other mouldies I have put together. As with all of these models you have to be careful because of the finish, room to work, and tolerances.

So I will use a small dremmel tool to remove the epoxy, bend the wire over about 8mm, drill a 2mm hole to insert it and give it purchase, then use a syringe to add more epoxy - I use 30minute mixed with milled fibreglass to give it strength and durability which seems to work well. One has to be careful to bend the rod at the right angle for the ball joint to be in the correct position.

Hopefully this will work.

[Callsign Tarnish]

The more I see this come together the more I'm sure I'll never buy anything from this company.

[Peter Garsden]

That is a matter for you Callsign, but I have had 3 models from them now and find them all exceptionally well finished and high quality. They compare very favourably with the competition. The point is that they all fly extremely well and that, after all, is the acid test. The point above is something which can happen in any process and is easily remediable

[Peter Garsden]

Well I looked at the other tailplane and realised that we had the same problem so removed it. I bent over the end 8mm.

I used the Dremmel, and and ground away the existing resin. I then filed a hole in the wiper so I could drill a 2mm hole in the elevator. I fitted the control rod end into the hole having first covered it in a mixture of Finishing Resin, and milled fibreglass.

I had fitted a nozzle to the end of my syringe and cut the tip off. I filled it with the resin then squirted it into the gap as you can see

[Peter Garsden]

I had fitted the Bluebird Servos into position in the fuselage front. I had checked the torque and it is over 4 kg where as the voltage is 6 volt minimum. I only have 4.8volt so I am wondering if it will power the servo when we have more servos connected. Accordingly I have ordered a 6 volt Ni MH battery to see if it will fit. The wing servos are rated to 6 volts but with 6 servos connected I doubt whether the voltage will be as high.

I have cut down the clevises to the last hole.

Because one of the snakes as a kink in it the movement has some resistance and is not as loose as I would like, so I want to keep the heavier torqued servos ie the Bluebirds

Next job is the servo plugs.

[James Hammond - Aeroic]

HI Peter - if you do unfortunately develop a kink in the teflon outer tubes - just use a couple of drops of the teflon bike chain lube you can get from bike shops.

This stuff usually makes almost anything work much more freely. By the way it works on almost any stiff linkage that you want to keep slop-free but still easy to move.

Good ones are: Muc-off, Dupont chain saver, or Finish Line Dry - they are all are dry after the carrier liquid evaporates.

Comment:

On these forums all are entitled to their opinions and the right to express them - this is how we learn and exchange information. But I sometimes think a few people express opinions, mainly of a negative nature, without having actually made or flown the models that they talk about.

As you are one who actually DOES know what he's talking about, and HAVE made and flown the modes in question, thanks for the compliments about the flying!

Cheers, Doc.

[Andy Meade]

Wait, so the elevator links just cracked off? Good grief....

[Peter Garsden]

Thanks for the tip Doc.

[Peter Garsden]

It's a shame that this thread is turning into one of my cases at work - oh and there is one unique thing about Aeroic planes and that is the sinewave wing spar which is is so much lighter and stronger than a conventional spar. And Doc is proper aircraft engineer, not someone that just copies other people's designs. He used to design for RCRCM but left because he was dissatisfied with the quality of their lay ups. That is the last of the informal litigation (I hope)

Have now connected up the tailplane, and the servos in the fuselage and everything works fine at 4.8volts. Just got to attach the plugs on the ends of the wires in the fuselage, and put the servos into the wings and we are done.

You can see here the ball link connectors and the cover for them which will be taped into position, as will the cute green end cap.

The links are attached first with cyano, then epoxy under the shrink tubing which is then shrunk with a soldering iron. These will never come off and a great idea.

[Andy Brassic]

Peter I personally wouldnt use the heatshrink , I have done this in the past and if by some amazing accident the cyano and/or epoxy fails you end up now knowing the fixing is broken as the flex in the heatshrink covers the failure ,looks neat but I dont do it anymore in fact I dont use the cyano anymore either just a good epoxy.

Be interested to see what you think of the light air performance as I've seen several of these fly now

[Brett Larrett]

Very good point, all it takes is one rough landing for the elevator to be jerked and cause the glue to fail. The flexibility in the heatshrink would allow the break to happen without the heatshink breaking and making it obvious there is a problem. If you wiggle the sticks on the ground with no force on the elevators there may even be enough "hold" in the heatshrink to make it seem like the connection is fine.

Plus, the Redshift is pull for up, ordinarily I would say thats good, but in this situation if the glue fails and it seems ok and you launch, then the heatshink may hold it until you are in a fast move and go to pull up and thats when the rod will simply pull out the heatshrink because of the force of the wind on the elevators.

[James Hammond - Aeroic]

Hi Guys, to be honest if this joint is going to let go, then it's going to let go.

If it did let go then it probably was not done properly in the first place, as there is nothing in normal use strong enough to jerk or shake it loose. If properly bonded, then there is simply not enough mass to provide the kinetic energy needed to cause a detachment.

I use epoxy only too, by the way, but while it's still soft I shrink the tubing on - which no doubt speeds up the curing process. The heat shrink is just another layer of insurance - I hope.

Scrupulously clean parts all roughened and cleaned that one last time with acetone or the like and a really good 24 hour epoxy should do the job, heat shrink or no.

I just like that last feeling of finishing that heat shrink gives, but each to his own.

Cheers, Doc J.

[Peter Garsden]

Interesting indeed....will have to think about this one.

Battery advice please - bit of a quandry.

I ordered the 6volt 3300 mah NI-MH battery shown and it is far too big. I want to keep the 6 volt Bluebird servos, so I was wondering if a LIPO with a voltage reducer would work? The problem is that the KST125MG are only rated to 6.0volts and a LIFE solution is 6.6volts, so I don't want to risk burning out the servo, but I do want 6 volts to power the Bluebirds in the fuselage which are rated from 6 volts to 8.4volts?

Any suggestions as to what LIPO 2S and what voltage reducer would fit in the space?

[Andy Brassic]

Peter this is a good start

https://zepsus.com/product/magnetic-bec-14a/

might get a bit smelly if you pull 14amps through a normal style rx plug .

strange choice of servos with wing at top end 6v and fuz at bottom end of 6v .

Andy.

[Brett Larrett]

Hi Pete

Hyperflight used to do a BEC designed to be connected between the receiver and each servo. For your set up, if you were to go with a LiPo of LiFe battery, you could power the Rx and fuz servos direct from the battery. For the wing servos, which are a lower voltage, you could use the BEC connectors to reduce the voltage to 5v.

Problem is I dont see them on their website anymore. They still have a picture of it under the Electronics heading but when you click into it they only have the magnetic switches (its the image for Lipo Regs & Switches).

Personally, I would always use servos with the same voltage ratings. I wouldn't mix high voltage and medium voltage servos together. Others might say its fine, and it probably is with the switch in Andy's link, but I think keeping it simple is the way to go.

Earlier in the thread you mentioned you wanted the 4kg torque of the 6v Bluebirds. If it was me, I would get 2x Bluebird BMS-390DMH servos for the fuz. At 4.8v they are rated to 4.6kg so more torque and you would be able to use the 1600mah battery in the image above that will fit that nose perfectly. Only £24 each at Hyperflight so wont break the bank.

Plus that means both your wing and fuz servos are 4.8 to 6v so if you ever wanted to go 6v it would be fine. The components shop have a note stating they can do custom packs. I doubt they would charge too much for a 6v 2/3a pack with either a -== or --III design and that should fit your nose.

Hope this is helpful, as that was the intention.

Brett

[Peter Garsden]

Thanks Brett and Andy, very helpful. Will see how we go, but food for thought. Problem is, I didn't realise until I checked what the rating for the servos was, still never mind.

[Peter Garsden]

Anyway, I am on with the Wing and Flap Servos. The larger 10mm servos are a squeeze in an 8mm thick wing. I had to bend the threaded 2mm rod. I replaced the clevises with M2 Mutliplex versions which are much better. I now have to mix up some epoxy and milled fibreglass to glue in the frames with cling film to protect the servo and make it removable

You can see how I filed the scoop out of the clevis to take the proximity with the servo barrel as it rotates. I didn't need to file down the other end which fitted the flap clevis nice and tightly

You can see how one has to route the aileron wire round the top because otherwise it would be in the way of the control rod where it comes out of the fuselage. You can also see that I filed away the bottom corner of the frame to make room.

It is obvious that this plane was made for the tiny 8mm X08H servo you can see in this picture. Am waiting for the frames which are much smaller. The frames supplied are fine for the larger 10mm KST Servo

 

Edited By Peter Garsden on 18/12/2018 18:44:01

[Peter Garsden]

Have not posted for a few days but have been busy with the other wing.

The frames for the smaller servo arrived and are fitted into the other wing, so just the left hand wing. It is a lot easier and quicker to install the 8mm servo which is a feat of modern engineering from KST. It has a whopping 5.3kg of torque from such a small motor - amazing.

Making these mouldies is such a fiddle because there is so little room for things and you are playing with tolerances of millimetres.

I have used a mixture of epoxy and milled fibreglass to glue the frames in, and wiped out the surface with acetone. It is difficult to mark the frames because finding something which shows on black carbon is a challenge.

Once roughed up with a file I used a magnifying headset because the screws as so small. The instructions suggest 2 tiny washers which I think stabilised the servo.

You can see the scoops I have filed out of the clevises. I used a round metal file which works well.

I lined the frame with cling film to stop it sticking and weighted the servo down with a slug of ballast.

[Peter Garsden]

The good news is that I finished the Redshift, put it in my Hobby King bag - must make its own Radiator Insulation bag, and took it to the Gate Site above Leek to maiden it.

When I got there the wind was very turbulent and fluctuating between 25 and 37mph - not good conditions for a maiden, so I flew my D60 instead which was fine with lots of ballast in it.

The wind then died down a bit so I assembled the Redshift, only to find that one of the elevator servos for the V Tail had packed up. I think it was binding and couldn't cope with the torque.

I have now changed the Servo for a Savox 255 which has 4.3KG of torque and is rated for 4.8volts. Seems to work OK so I am waiting for a maiden opportunity.

Mark Ollier was there and took this picture

 

 

Edited By Peter Garsden on 04/01/2019 18:07:06