Durafly Bf 110

[Erfolg]

I have purchased a Durafly Bf 110, the kit version, that is with nothing in it at all.

Has any one built one? If so, I am hoping that i can build on your experiences.

I have not started on the model as yet, other than read the instruction book, which is solely related to the essentially completed model, which requires the assembly of a few large assemblies which have everything pre-installed.

You may wonder why I did not go for this version, just two reasons, one is that i wanted to use more powerful, and better quality motors than  those which come with the kit and I had the retracts.

Again you may wonder why i had the retracts? It was my intention to make my own Balsa and ply model, using the spares available for the nacelles and UC. My preferred airfoil is E205, which turned out to have a more rearward maximum thickness, a sharper, plus higher entry and is slightly thinner. In short there would have been gaps with my preferred airfoil. Negating some of the hope for short cut and advantage sought.

My first impression is that model has more wiring than the average car, to drive the numerous servos and motors.

Edited By Erfolg on 01/01/2015 11:43:10

[Colin Carpenter]

Hello Erfolg. Fellow club member maidened one (full Kit) last summer on a perfect evening. After all checks it took off, climbed vertically for about 3 seconds and fell out of the sky ! Flight lasted less than 6 seconds ! don`t think it was the plane, just pilot error. Plastic bag job. Certainly the take off rate was more than adequate so I guess the standard motors are ok.

Colin

[Erfolg]

Colin

Thanks for the reassuring news.

You are probably right in your thinking that the standard motors are up to the job, power wise. What I do not like are the so called bell motors with their knitting needle strength, threaded shafts. From observation they bend rather easily. Given that our field suffers from longer than standard bowling green grass, most of the time and the undulating nature of the field (it is an old rubbish tip), nose overs are ever present threat, even with a good landing.

I have started looking at the kit and trying to decide what to do, first.

There are a few very obvious things. Which potentially make things difficult.

• The two servos in the tail end of the body will be difficult to both insert and maintain
• The wires from the two rudder servos at the back of the plane, have to pass the two rearward mounted servos and room for a couple of "Y" leads has to be found. One "Y" lead for the rudders and the second for the rudders to the tail wheel servo.
• Two extension leads is needed for the two rudder and tail wheel servo and the elevator servo (the two rear mounted servos in the body).
• The semi separated body has to be joined at some point, when? before or after getting the servos and wires in?

The wings also need a fair bit of thinking about.

The assembled kit avoids all these issues all has been done!

[Colin Carpenter]

Erfolg. The motors survived the crash despite the model being returned to its kit state ! Agreed, I don`t like those bell motors ,much preferring a standard shaft and conical adapter.

PS. My Rainbow didn`t survive adding the spats and foam leg covers. The flying qualities changed to become uncertain when applying much elevator. Guess the airflow over the tail changed? Shame ! I loved it.

Colin

[Erfolg]

Colin

I still have my HK Firenza/Rainbow. I have thought of modifying my own by by doubling the battery capacity, by paralleling, the aim is to double the flight time. I bought the model to get through the "A" test, I found its duration was inadequte, to fly the sequences required, which were about 10 minutes where as the lipos were only lasting 6 minutes with careful throttle management. The model did not always being near to the stall, it wanted some speed.

At present I tend to fly my Parkzone Alabatros at every session, a Delta and my canard. Which is now supplemented with a with a HK biplane which flies very well.

I hope to get this 110 finished for the Spring, as there appears to be a lot of wiring to undertake and quite a few bits of body to stick together that the PNP has done.

[Colin Carpenter]

Hi Erfolg. Good luck with the build .Post a few pics. I am flying my Sebart S Bach 30E as much as possible. It`s so neutral and presents no fear factor on landing unlike the Rainbow which came in very fast. Sebart won`t do a chandelle like the Rainbow however ! I believe my clubmates 110 is repaired and ready for another try.

Colin

[Erfolg]

I have now started on the build of the model.

I would advice anyone contemplating building this model, in the manner I am undertaking, to consider what it is they are contemplating, The Partially (that is essentially) built model has all the difficult stuff done for you.

The kit is pretty much that a kit, very complete in that all the mouldings are supplied and a lot of the bits and peices, along the same lines as an Airfix kit. There is more building in this moulded plastic kit than any of the others I have built, which have been, a GWS Texan, A Nitro Planes Dornier 355, HK Firenza, and a HK Arcus. I am not claiming to be an expert. Definitely not, just an average modeller, who does recognise this is more of a kit, than you may anticipate, unlike the Arcus which seems to assemble itself.

To start the box

As can be seen a most professional box, which comes inside a close fitting outer.

Everything is seperatly packed, taped in place. Two boxes of bits and peices are also supplied. Pretty impressive.

It is from here that things get tricky,

The

As designed the body has two servos in the back end of the body, and this body is pretty narrow, it also shares space with the servo wires and "Y" lead from the two servos on the tailplane.

The elevators are designed to be driven by a "Y Fork Yoke", which is restrained and guided in a tube, which is inserted into a heafty ply (12 mm thick) bulkhead. The servo for this is buried in the fuz, access via a small hatch. It is intended that the servo is bonded to the side of the body. The servo arm is slotted, with a slider, which operates the push rod by a cam action. Allthough this arm is supplied installed, I needed to make my own, due to using a HXT 900 servo which is slightly taller than the intended servo. Trialling the set up, i saw it actually works quite well. Although I have decided to locate the servo in the cabin area, as maintenace at the intended location would be a problem and replacement, hmmm, well.

In the case of the tail wheel steering i have decided to leave this as intended. Although maintenance is all but impossible, I can just fix the tail wheel in place if it comes to it.

[Erfolg]

One aspect of building which gives me pleasure, whilst managing to complain, all at the same time, is turning over in my mind, what might be a problem, what is defiantly an issue, then the slow dawning that ther is potentially a problem that I had not initially envisaged.

One such is the rudder/tail wheel arrangements. From reading build blogs and advertising type blurb, it had been my intention to use a "Y" lead. Then during checking tail wheel movement, I suddenly thought, what if the sense is wrong between rudder and tail wheel! Reversal at the Tx would not work! My initial solution was to buy a servo reverser and plug it into the harness. Then it also dawned on me that the way the servo tail wheel geometry is set up, it will not be possible to adjust the moment arms. Then it slowly dawned on me, why not plug the tail wheel into a separate channel and then mix both the rudders with the tail wheel using the features of the Tx assigning both to the rudder stick. That way i can independently have whatever throw and direction of travel i want on either feature.

Fast on the uptake or what, but it all keeps your mind active!

Working on the elevator now.

[john stones 1 - Moderator]

The obvious often escapes us Erf, we get there eventually but some days it takes a while

John

[Trevor Crook]

Wow, I'm glad I bought the complete item! The fitted bell motors have more than enough power, and having all the servos fitted makes life easier. It flies quite well, although surprisingly is prone to nosing over. Watch out for tip stalling though. I tried a scale-like half throttle take-off and it flicked in. Quite easy to repair, prop blades broke but shaft stayed straight. Luckily I had some spares.

I'd say it's quite a good effort, but doesn't handle as nicely as the other Durafly models I've experienced. I've got the Trojan and Vampire, and my son has the Spitfire 24, Skyraider and Vampire, all of which are excellent.

Anyone know why HK haven't had Durafly in stock for ages?

[Erfolg]

Trevor

I have read on one blog, how the builder had set the UC with a slight forward rake by packing the rear UC servo mounting. As with many things, I cannot find it again, what ever i put in the search.

I am left with the impression that the Lipo has to be positioned quite a long way back to achieve the correct CG. What is your experience.

The CG may be more of an issue for me as the motors are slightly heavier as are the ESCs, being higher rated. This will have an impact on Lipo selection as I was hoping to fit a larger Lipo, for more duration as well as the issue of drawing more energy.

As much feed back as you can supply will be greatly appreciated.

Edited By Erfolg on 07/01/2015 10:45:12

[Trevor Crook]

Erfolg

I have put some washers under the rear U/C mount, which helps a bit. You can't fiddle too much because it will affect correct operation of the doors.

It's been a while since I took the model out, so I can't remember exact details of the battery position, but it certainly wasn't pushed right forward. I'll try to do some c of g measurements for you this evening.

I use Dynamic 2200 3s packs, which are quite light. I don't know what you are looking for in terms of duration, but these give ample performance, and if flown around in a reasonably scale manner at least 10 minutes should be acheivable.

Although I suffered tip stall on take-off, all the approaches and landings have been stress free, treating the model with a bit of respect, of course. Like many scale electrics, it's best to bring it in with a bit of power applied.

[Erfolg]

I have found the reference to the UC fix. I was looking for the wrong thing

 

 

Can some one tell me where the embed and the 450 size is to be found

Edited By Erfolg on 07/01/2015 14:36:46

Edited By Erfolg on 07/01/2015 14:39:10

Edited By Erfolg on 07/01/2015 14:40:04

[Trevor Crook]

That's a good video. I got my 110 into the shed to do some measurements. The c of g is 75mm back from the l.e. at the root - aft of the recommended range! This could be why it's a bit prone to tipstall. I normally err on the nose heavy side, but I guess I was trying to solve the nose over issue. The rear end of the lipo is in line with the wing l.e. at the root, and there would be room to move it forward. I'll leave mine where it is - it's not vicious once flying.

I reduced the wiring by soldering together everything I could, rather than using connectors, as there isn't much room in the fus.

One small scale niggle - I cut off one exhaust stub per set as Daimler Benz made engines with 12 cylinders, not 14! I also added an aerial mast and rear gun.

Have fun with the rest of the build, and feel free to ask any further questions.

[Erfolg]

I also much prefer to fly with a forward CG, as I have found out the hard way, that putting the CG at the absolute rearward position is counter productive. I have also found that the CG being absolute forward is equally as bad. It took one of the Uks best BARCS legue pilots to educate me, why my model was such an absolute pig to fly (forward CG). I found that the rearward position made the plane so sensitive in pitch, you lost more height in pitch ups, than you gained from the visual indication of lift. It seems extremes are not good.

I will post a few pictures of how i have dealt with tailplane servos and tail wheel servos in the next few days.

My kit does not have the navigation lights, nor the lens to cover the apertures, I guess yours does. I would not have bothered with the lighting, not having the lens is a slight nuisance.

As I fly Futaba, the aerials are a bit of a nuisance on a small fuz. I had thought i had a solution in using the rear gun to hide and carry one of the aerials. Then it dawned on me that the canopy comes of for arming etc. Grrrrr!!!!!. Iy is a pity that the original aerial poked out of the mid canopy. I then thought, could the Schrage muzik )Jazz) be used, but they would be so far down the body as to be impractical. I am guessing most are using Spektrum Rxs as there is no sign of the aerials.

[Trevor Crook]

Yes, mine's got a Spektrum AR600. The short aerial fits across the fuselage width, the long one lies down the fuselage towards the tail.

I lost a wingtip lens in my crash, and made a new one with a piece of scrap acetate from some packaging. I shaped it by pulling it around a shaped wooden mould while blasting it with a heat gun. If you aren't fitting lights, you could put lightweight filler on the tips, and paint it. The landing light lense can be scrap acetate, bent round and glued on.

[Erfolg]

I have made a little progress. I will state up front I have made a change which is not as HK intended the model to be built and will in all probability will not be the last. Not because there is anything particularly wrong about the kit. In fact if I had built the ARTF version i would probably not been any the wiser about the things which i do not particularly like.

My changes are all driven by maintenance, as i know as an ex engineer, that equipment fails, also the more involved is any maintenance is, the more prone to failure is that system or part.

I have now routed the elevator servo to an area where it can be maintained, relatively easily. There was a choice which was to mount the top of the servo externally or move it into the cabin area. I chose the latter, as I was a little worried that I would weaken the back end, if I did not compensate for the opening required.

The support for the cable is made from flooring grade (rubbish) Depron, with Christmas card laminated on each side, using Gorilla  polyurethane glue. Although it is no better than the other manufacturers in performance, there is one area where it seems to be better, that is shelf life, is it the smaller bottle with less air in the bottle. The item is is held in the model using PVA.

I am now looking at the wing and maintenance issues there.

 

Edited By Erfolg on 09/01/2015 18:02:16

[Chris Bott - Moderator]

Erf is there anything you can do to make the photos a little clearer? It looks like you have quite sharp bends in that snake outer (if it is a snake outer).

[Steve T]

Erf, sorry but I have been trying to follow your thread but the photos leave more than a little to desire, I wear glasses for reading but almost went back to specshavers to complain !

Edited By Steve T on 09/01/2015 19:30:18

[Erfolg]

I will admit straight away i am no photographer and i am more than happy to blame the camera as being useless,

I have read the instructions that come with the camera, with the view of increasing the number of pixels used as a potential means of improving the images. It was at this point I had it confirmed that i am no photographer, and it is my assumption that auto meant, that it did everything. Apparently for close up images I needed to do a bit more.

So I will post a few more of the older images, retaken

This image shows the elevator sliding mechanism, which is a new for models type arrangement for me.

This view is of the rear hatch, showing where the elevator servo should be by design. I have relocated this servo, as it could not easily be maintained and replacement is all but impossible.

The repositioned elevator servo. A little more work is required, the inner needs to be shorten a little to move the servo back to where it ideally should be for space management.

with respect to the point that Pete raises with respect to tight radius outer on the supporting board. I was a little concerned that the original cam type action would have friction from the cam type follower in the slotted servo arrn and in practise I could see that there was a side load in the rear sliding bearing arrangement.

I always try to arrange any snake as straight as possible. Secondly i now only use Goldberg Golden Rod or wire. In my opinion one of the few products where generics come nowhere near in performance. Others have been a constant source of problems for me from steel bowden cable, ptfe inner rods, and copies.

In this case I carefully adjusted the arragement to obtain true liner paralle action where the rod comes out of the inner and in addition, the friction, hence force required to move the inner was very low. The same concept was then repeated at the pinch coupling which I made from odds and ends.

I am now strting on the wings.

This is the bare wing. It has to carry the aileron servo, the esc wire, the motor/ESC power wires and the wing spar. In the ready built version there are additional set of wires for the navigation lights. I will not have these.

However, the way the ready built appears to be built, there is a wire that runs the full length of the wing inner panel, to the servo. If the servo is damaged, it appears that it will be a big deal job to replace the servo. From my experience the aileron servos can fail and need replacement.

I will be hiding the servo to extension lead cable and plugs in the radiator, to minimise the amount of damage inflicted on the model to replace a servo.

I would like feed back from the experiences of those who have flown the model and defiantly anything which can be said about the build, however apparently trivial.

Ah, On e apparent black mark for the kit, it is apparently short of 4 screws for the aileron brackets/arms.

[Biggles' Elder Brother - Moderator]

Wow - that's a great improvement photo wise Erf! Well done.

BEB

[ken anderson.]

hello erfolg- get in touch with victor saliba in Malta via the PM ... he and his son stef have one and have flown it-he will tell you what its like.....good/bad etc..he's a good lad and will be pleased to advise you..

ken Anderson...ne...1 international help dept.

[Erfolg]

Ken

If Victor is a member of the site could you make him aware of the thread, with a view of feeding in his experiences.

I have tried a search for Victor and he does not come up using the search, is there another way to locate individuals.

[Chris Bott - Moderator]

Click on "Inbox" on the top bar, Erfolg, that takes you to the messaging page.

Click "Compose new message" and you'll find a search box for finding other members.

[Pete B]

Go to your 'Inbox', Erf, select 'Compose new message', then type 'vic' in the 'To' field. A drop-down box will emerge. keep adding the letters of his name (don't hurry it, there can be a delay) until it appears, click on that....

Pete