Durafly Bf 110

[ken anderson.]

erfolg-I've contacted victor on his bit of rock in the middle of the med(Malta) and he say's to give you his e-mail address ....which I've sent you via a PM......give him a call..

ken Anderson...ne...1 international hub dept.

[Erfolg]

Assembling from the kit form highlights what good value the ARTF version is, both in time and cost.

I am now of the opinion, it would have made better sense to have bought the ARTF version and just swap out the motors.

The motor harness emphasis this point

There is a lot to it, a lot of work, I must have spent 2-4 hours on it. Thinking about what needs to be done, then doing it.

My Lipos use Deans style plugs, the last plug therefore needed to a Deans or a X60 to Deans converter. I decided to take the latter route, making my own, rather than purchasing one from HK. The main reason for this is the "Y" power leads with built in BEC unit, is very compact and nicely made. Certainly better than my skill level

 

This photo show the two plugs soldered together.

I could have left the conductors unprotected, other than a sleeve, just as buzz bars are. Hmm I thought, accidents will happen. So i have potted it in Epoxy.

Then to pretty it up and provide a secondary layer of protection, I put some heat shrink on.

I have now started in getting the tailplane ready for installation. I thought a comparison with the HXT 500 that i would normally use with the Turnigy MX 95E, may be of interest to some. I have always been very happy with the HXT 500s, in the past. But these units promise better performance at much the same cost and are lighter still. These servos are for the rudders, so if they give trouble, it is not quite as critical as the elevators or aileron.

Edited By Erfolg on 12/01/2015 19:11:39

Edited By Erfolg on 12/01/2015 19:13:01

[Victor Saliba]

Dear Erfolg, we (my son and I) have a Dynam Bf-110 which is 1500mm span and comes complete with 3 bladed props, flaps, retracts with doors etc. It flies on 4c 3200mAh Lipo for about 6 mins. We did not encounter problems with the model, it flies great and looks impressive too. I also have the Dynam Me-262, nice couple.

Edited By Victor Saliba on 13/01/2015 18:31:55

[Erfolg]

Hi Victor

There seems to be a lot of similarities between the Dynam model and the HK Durafly, although there is a difference in that the Durafly model is smaller at 1200mm. Then the Durafly model does not incorporate flaps as standard

The same style propellers are even used.

It is the build process which at present that occupies me and any input will be appreciated.

[Dave Hopkin]

I'm impressed you managed to solder those two connectors together without even the slightest melt of the plastic housing - Very neat.....

[Erfolg]

Dave, soldering the two plugs together is quite easy, the hardest part was keeping them together for the first soldered joint.

With cable, it is often much harder particularly at the larger sized cables,on this model i have used 14 AMG, which is quite light, compared with my more recent models. Here I find the cable carries much of the heat away. So even heavy wattage irons are not much use without a big tip, which seem hard to come by these days.

[Vecchio Austriaco]

Hi Carl, a very interesting build blog. By the way it is AWG (American wire gauge) and AWG14 is approximately 2.1mm2, so you are right, not a lot.
I like the fact that the guy on the video you linked is German - matches to a Messerschmidt plane
Greetings from the world of cables
VA

[Victor Saliba]

Hello Erfolg, I don't know how to help you mainly because I was never in your situation. I don't know how the Durafly model is compared to the Dynam, I don't think they are the same. The Dynam's wing bolt to the fuselage with 4 x 3mm screws. You need to arrange all the wires in the centre section of the wing, there's lots of them. Once they are sorted, job done, it took me about an hour to sort them. The only dislike about both the Me-262 and the Bf-110 is that they are 1 piece model and one must have a medium size car, like my Opel Astra.

I hope that by now your model is finished and all problems sorted out. Good luck.

[Dave Hopkin]

I find I get better results from a solder gun when doing Deans plugs or piano wire bits, I have a 10o Watt gun from B&Q and it heats up almost instantly, the most useful part of it is when you are soldering deans plugs push the wire against the tinned terminal using the tip press it hard against the terminal while the solder runs then release the trigger but keep the pressure on while the solder solidifies

[Erfolg]

Dave

I also use a solder gun, at other times an iron.

I have thought of te comments Victor has made, and how I consider this build.

I can only admire how HT et al, manage to assemble models of the ilk of the 110, at the price and perhaps more surprisingly, with a degree of cleandiness and precision that I cannot match. At present I am building two 190s, one a Balsacraft kit, the other a modification of the kit to make a "D", rather than the "A". You might think I consider the Airfix like HK to be inferior, on the contrary, its is different and just as challenging, in different ways.

I have been working on the wing. I have to admit I have only admiration of the quality of the mouldings, and a grudging admiration, how these young Chinese people manage a quality of build, I just do not match, when buying the ARTF version.

This is the bare wing, which needs the everything placing inside and glueing.

This is a picture of the servo plug in the radiator area, so that it can be changed with the minimum of work.

With radiator cover in place.

A picture of my servo box, I have never liked solid hard wood rails, for years I have mounted my servos on a balsa beam with a ply facing, lighter and does the job.

With servo in, there should be a pic with the thing mounted in the body.

What is not apparent, is how little room there is inside the body, it is all very tight.

I have assembled the wing, which I will post a little later. This process further enhances my estimation of how good HK and contractors are in suppling a mostly assembled model, it was for me quite a struggle. Maybe other modellers would do better, yet, in many ways that is why I model, it is not as simple as sticking stamps on envelopes.

[Erfolg]

I contiue to make slow progress, on the wing

The photo shows the motor feed and ESC control cables, inserted in the premoulded chanal, which are immediatly above the UC servo mech,

From an internet search I have found that there is some advantage in canting the UC slightly forward. This achieved by inserting a 1.5mm max washer. od course I do not have any washers of this thickness, so have been forced to search by washer and bolt tray to find washer combinations which come to this figure, So it is a 30 & 40 thou wshers cynod together to provide 0.070" build up which is some wher near to the quoted 1.5mm. Then I found that the washers were to wide, requiring a flat to be filed on tjem.

These are all the wires I intend using, the ARTF has more for the navigation and landing lights. A bit gimicky for me, plus even more fiddly work. Again i ask myself, how do HK do an ARTF for the price at such quality?

Again therer is a picture missing with the inside cover glued in place.

There is universal advice that it essential to trial fit the spar in place before any attempt is taken to glue in place. I just sanded it down to smooth the surface little. In my case both sides fitted well. I have servations about the glue supplied which appears to be a evo stick, or one of the universal adhesives which a solvent based (petroleum), which generally in my experience do not stay liquid for long. So I used PVA, which I have used sucessfully on Depron previously, it just takes an age to dry, possibly a day to 14 to dry, but dry, it does. Not only that it seems to stick large areas as well as many other glues.

I then assembled the second wing half to the first, using the adhesive provided for the flange. It was a mistake, Stupidly I had not assembled both wings simulataneously onto the spar, just in case I could not seperate the two halfs. It was now that I discovered that the flanges had a slight bow, which leaft a small gap at each end. After a lot of struggling and the use of eleastic bands i managed to get a reasonably good fit. That the glue could not hold. I then used Cyno to achieve what other adhesives could not.

I am now working on the motor installation, again an issue due to my non standard items.

You can see that the ESC is inserted in a ventilated slot for cooling.

[Erfolg]

Deviating from the std build adds much more time, that being the down side.

There is an up side, in that you can consider if all the installations detail as per manufacturer intended can be considered and amended if you feel strongly enough.

Todays first issues has revolved (I do like to slip them in) around the use use of non std motors. A lot more packing is required to achieve an acceptable positioning of the props.

The kit comes with the prop adaptors and props, these are nice items to look at. I have decided to give them a go, i had intended using a 2 blade propeller. This does mean that the Kv on my motors is not ideal and may prove unacceptable, which will require some new higher Kv motors of the same pattern.

However the main effort has been in fixing the wing to the body. In principle not hard, just two screws. In practise, a bit of a struggle, as the multitude of wires need to fead through a couple of small gaps.

My new concern is the tailplane, as designed, it is stuck on. I do not like this solution as there is a "Y" lead in the tail with the two rudder servo leads feed to it. If either of the servos is damaged, it would become a big deal effort to undertake a replacement. I am tempted to contrive a peg and bolt on tail, perhaps with a couple of blobs of adhesive to hold in the correct position.

I am also dealing with the canopy arrangement, as the plate that closes of the Fuz and holds the canopy has bent due to stresses, being relieved. I am moding this to hold it straight. Before finishing this assembly of.

[Erfolg]

It may seem that this project has joined my others, stalled due to a lack of enthusiasm, not so.

I have had a few problems with the build recently, many of the bitty type, you probably have the same type of issues. This needs to be done, but that is dependant on that, and I cannot do that until i have got that thingy me jig.

My first minor issues have been the prop drivers, they were drilled for 3mm shaft. My motors are 3.175mm. To open the holes out i needed a lathe,I do not have one. In the past I have gone to a LMS, although I have not been there in a year, I do not know if they are still there. It has a major problem, the stock is low, to non existent as far as modellers go, so not many modellers go. As the turnover falls, the stocks fall further, even less modellers go. The last time I went i purchased all the spar material (spruce) that he had. No Solafilm is now in stock and so on.

In this case I asked around the club, one member has a lathe. I arranged to be allowed to make use of it. First, I purchased a 3.2 drill, then went through my stock of old drills Until i found one that measured less than 3.2 using a micrometre and a old fashioned drill gauge, the sort that deal with both fractional and number drills (do these still exist). I was taken to the garage where the lathe is kept. Oh, my, oh, my, what a workshop. Two MG sports cars were under dust sheets, a MGB, and the more modern MGB that was produced in very limited numbers, both concurs models, lines of winners cups lined a shelf. Ah, the lathe, yet again, far better than i saw in industry, complete with all the accessories you could hope for. Seemed a little pathetic just to drill partially out the bores, yet that is what I did.

Back home, as i expected the holes were a transition to interference type fit, they would not go on the shafts. I had planned for this, I used an old drill shank, covered in Brasso, to ease down the holes, using an electric drill. After some careful lapping the shafts were a good fit in the holes.

I then turned my attention to the tail plane, here I used a PM Centre line marker for hinges, to mark where the dowel should go. Yes, I do not like the idea of glueing the tail on. My main concern is maintenance/replacement of failed servos, the second is I am not that confident of the glue that is supplied.

Not a good picture, although for any who have not seen the a Pete Miller pin, this is one of a set of three.

Picture of the pin in place ready to mark where to drill a hole for a locating dowel.

A few pictures of the dowel and bolt/screw and the plastic hole liners.

The tailplane bolted in place, with a small ply anti compression plate.

I may have a problem with the propellers, the motors used are high KV motors, which are pulling 200w combined on a 1.4Kg model. So are about 100w down on what I would like. I may need to swap them out for some lower Kv motors, better matched to the propellers.

[Erfolg]

Disaster has struck

I have received my new "Y" leads, which have been installed. Everything seemed to be working until I tried the UC, then, only one deployed, the other moving slightly.

I have tried my servo tester and believe the servo has failed but why I do not know. It was tested prior to inclusion. I am considering what is to be done about the issue.

I have looked to see if i can lower the leg manually, although i cannot see how to do it, nor what the internals of the unit are.

I started to see if I could release the lead, with a view to swapping it out with a new unit, to my horror, it seems it is held fast. On that basis the wing will need to be channelled out, unless I can think of another solution.

[Bob Cotsford]

Are they electronic retracts? Would you have enough of the lead inside the nacelle to splice the new unit to it?

Just a thought, if you are driving them through a Y lead have you swapped the Y round to test both legs are ok and that it really is the retract?  Also, have you tried the unit unscrewed from the model?  If the mount plates are distorting when you screw them down this can cause the units to jam.

 

Edited By Bob Cotsford on 30/01/2015 13:41:32

[Erfolg]

Bob

Yep, they are electric.

Is there room, to splice etc, ahrrrr, NO! It is just far to tight and inaccessible.

I have just being checking the cost, £15.54, oh no, not another £12 for 54p I thought. Dam, dam , dam, Why oh why are spares not available from the UK site. Then I thought, you never know your luck, try the UK site. Oh Lordy, Lordy, yes, yes, yes, they do carry stock and @ £16.73 + postage.

Yes I know that PO charges @ £5 are similar to the handling charges, but hey, a result of sorts. If they used another logistics company (oh I do like modern word for the post) the cost would be approx £1.50 + their charges.

I will now order a pair, as that is how they are sold.

Ah, yes, to answer your question, I both, switched the leg on the "Y" and used my servo tester, all indicated that there is a problem. A quick look, did not make it obvious how you got inside.

[Erfolg]

Hey! I am a modeller!. We all know what modellers are like. Yep, you never know I could fix that retract. All us modellers know if it is put together, we can take it apart, Hmmm, that is if the thing is not stuck together.

So apart it came, a total of 8 small screw were involved, 4 for a flange and 4 to take it apart.

So what is inside? Surprisingly little, a small motor, a lead screw, a nut and a couple of tiny gears to increase the gearing. What about the electronics? Not a lot to look at. There appears to be a circuit board about 5mm wide and 20 mm long, which has the components integral with the board, probably single layer. At each end are the tiniest micro switches I have ever seen.

More importantly to me, it is knackered, all the wires were attached, two to the board and two from the board to the motor. I had hoped one had come loose. It just would not work on theservo tester.

I am not a believer in bad luck, but the UC had worked of the model, it would be pushing the concept it was just co-incidence that it failed on the first actuation in the model using the Rx, yet that is what has happened, Bad luck I guess

I am taking the wing of the model no easy thing, with the myriad of "Y" leads and leads. I will then carefully open up the wing, hopefully avoiding doing any damage beyond that planned.

Edited By Erfolg on 01/02/2015 14:04:08

Edited By Erfolg on 01/02/2015 14:05:01

[Erfolg]

I have cut the wing open locally, almost the equivalent of key hole surgey.

As with many things, what the problem you foresaw is often wrong, in this case i was spot on with my diagnoses, I had managed to get some glue onto the UC servo wire. Annoyingly in retrospect, it was just a couple of small adhesions. Annoying, because if I had just given the cable a good yank, the wire probably would have come free. I know why i did not try yanking the cable, was that I feared damage beyond just snapping the servo cable, perhaps damaging the ESC cable or less probably the two power feed cables to the ESC.

On a positive note, there does appear to be enough space to carefully pull the new UC servo wire, using the now defunct cable as a fish.

I am now waiting for the new units. Did not seem a rush last week, now eagerly awaited. Which is a nonsense as the weather is not good for any test flights.

Secondly, the new Lipo arrived this lunchtime, which needs the plug changing to a Deans. There is another positive here, HK are now using a non PO carrier. The benefit, they wait for you to get to the door, and not just leaving a card. Although, i must confess, that I now have an agreed arrangement with the Post Man, that anything that needs signing, just to leave in the porch. If it is then lost, I accept it is my reasonability and will not blame him. Just accept it has not arrived. Although in my case all my orders are of small monetary value.

[Erfolg]

I have now installed the new UC. This was incredibly easy, as the internal channel in the wing is plenty big enough for the servo plug, the fish pulling the lead through.

I am now struggling to get all the plugs and leads installed neatly into the body. There is very little space in reality.

The Lipo needs securing, in place, which is a 3600 against the 2200 recommended. This is because I would have needed Pd if a 2200 had been used, the 3600, negates this need.

All these problems are probably all problems of my own making.

Never the less I am almost there.

[Dave Hopkin]

Bashj on Erf bash on....... it'll soon be in the air

[Stevo]

Looking at the pictures it is a tight squeeze in there... Far too big for my fat fingers...

[Erfolg]

Although I have no photographs of the situation, part of the issue is the multude of "Y" leads, as follows:

• ESCs
• Ailerons
• UC
• the power lead distribution

Then their are the leads from the:

• Elevator
• Rudders
• tail wheel servo
• Bec unit and lead to  the Rx

Of course even the Rx needs some space

Which is made even tighter in that I made the 4 power leads longer than ideal, which in conjunction with the Lipo plug assembly is space hungry.

I must compare the model with my own design, to determine how scale the major dimensions are.

It does seem, if anything like scale, the full size cockpit must have been a tight fit also.

I do have concerns about the wing, in that my wing design, is non scale, omitting any lumps and bumps, so there are no radiators, which i have some doubted about. The full size may have had drag, but possibly a little thrust from the expanded air leaving the radiator cores.. In the model, they are just a lump.

Edited By Erfolg on 07/02/2015 20:54:54

Edited By Erfolg on 07/02/2015 20:55:44

[Erfolg]

This is one of the last posts for this model, as essentially it is finished.

I have managed to cram all the wires into the body, in a way that does allow the canopy to close. Not as firmly as i would like.

I have tried to taxi the model, unfortunately the moss is to long at present. I can see that a spread of moss killer and the lawn rake will be a necessity. At present, with full up, carefully opening the throttle, has the model balancing on its front wheels. Any more throttle and it would tip over onto its nose.

I am not sure how long this model will last, as it seems pretty heavy, compared with my other models of similar span. The manual, indicates that the model should come out at between 13,000 - 14, 000 grams, my model has come out at 15, 013 grams, which is 113 grams or 4 oz over the target weight. I always take the upper limit of quoted weights. My Lipo is much bigger than recommended at 3600 against 2200 recommended. I selected the Lipo on the basis that I prefer battery to lead.

I would show the wiring, but i am rather embarrassed by the mess, although I have tried to tidy it all up, to no available. A significant issue is the ESC leads, i have been generous, with hind sight, it is better to be a miser here, providing just enough, as these leads take up a lot of space.

[Erfolg]

The concern with respect to the mess of leads has continued. In some respects, this aspect has been made worse. I decided to push as many and as much of the servo leads into the tail section, to create space in the cabin area. This has liberated a bit more space for the Lipo cables and the BEC unit which is a real nuisance.

I have had one of those moments while deliberating on what I had done, did anything else need doing? When it dawned on me that the failsafe had not been set. Which was a damned nuisance, as all those stowed cables had to come out to permit access to the button.

In the case of the Frsky 6 channel receiver being used this is very simple. Just push the binding button, once, a green diode flashes twice, and the failsafe is set to the Tx sticks and switch settings. This is much, much better than my Futaba 6017 Rxs, the el cheepo ones at £70, which only set the throttle. Everything else stays where it is if a signal is lost.

I could not resist to taxing the model around the flagged front drive, not far, as it is pretty short, just a bit wider than the length (*2). On flat surfaces the steerable tail wheel seems to be quite good, in that it is not to sensitive for the take off, yet good enough to taxi about a bit.

[Frank Skilbeck]

Posted by Erfolg on 10/02/2015 13:34:27:

I am not sure how long this model will last, as it seems pretty heavy, compared with my other models of similar span. The manual, indicates that the model should come out at between 13,000 - 14, 000 grams, my model has come out at 15, 013 grams, which is 113 grams or 4 oz over the target weight. I always take the upper limit of quoted weights. My Lipo is much bigger than recommended at 3600 against 2200 recommended. I selected the Lipo on the basis that I prefer battery to lead.

15 KG !!!! just make sure you keep it below 400ft