Build and Fly review : Ultimate EP Biplane from World Models Man. Co. Ltd
First ... I have no commercial connection with WM at all ... I'm just a buyer who heard Santa's Call !!
Yep - went into Model Shop on way home from Airport .... arrived home with an extra package !
Wife put it under tree for me ... that lasted about 30 sec's - just enough to get this photo ...
Let's get on ...
Here's the box as handed opver after the painful part of paying out money ...
Box art close-up :
and laid out (I've removed various protective bits of styrene so you can see contents ... it comes very well boxed !)
Lets see what we have on the floor ...
Control rods, pilot figure, folding prop and boss, wheels, horns and connectors.
Wings, Fuselage, templates to hold wings for alignment when building, battery tray foam and strap, tail parts.
Decal sheet, wheel spats, cowl ..
U/C wheels and assorted ..
Overall out of box ?
Very well packaged and no damage that I can see so far.
Points I noted :
No hinges are fixed by factory, provided but not fixed. Big PLUS point to me - I like to fix my own ! Second no tape hinges here - these are mylar strip as I prefer.
The covering is so well done - that it's very hard to see any joins, signs of it being a super job.
The woodwork when spied inside is clean and boy is it light ! This reminds me of the 80's when Japanese Kits from Pilot came on market with super fine diecutting, Liteply and super detailing.
Folding prop ............ now this has me confused ! I've only dabbled with these on gliders ... never on aerobatic model. I always considered folders as less efficient ... so anyone explain this one for me ? I have Fixed props in the box I bought - so have both to trial.
This is one LIGHTweight machine that really looks nice.
What's not in the box :
This is the ARF version as against their RTF ... so it needs 4 x 9gr servos, 2830 1000KV or more BL motor 180W, 3S 2100 Lipo, 4ch radio + Y lead on ailerons ... prop and spinner are supplied.
I have for it :
2822 1400KV motor, 200W (with a RCTimer 2822 14 300W waiting new shaft)
3S 2280 30C Lipo's from my 450 Heli's
SG90 and Corona MG 9 gr servos
FrSky 8ch Rx
The motor is under sized for spec'd 10x6 props as a 2822 ... but given the power rating - should be OK. The RCTimer also less dimension is much more powerful than specifications ask ... so that should do well ...
Both power plants will be bench run on the 10x6 specified props before installation ... make sure no burn-outs etc.
Next post will be the putting it together .....
I'm interested in anyone else who has one of these machines and any comments - advice - faults found - modifications needed etc.
One comment I see on a Youtube video is to beef up the ply motor mount, they mention it's in the manual ... went all through my manual and no mention of this at all ... (with ply mounts - I usually epoxy fillet joints anyawy ... )
Till next post !
nice looking arf:tc:,please do keep us updated with how she goes together and thanks for sharing.[popcorn]
Bottom Wing ...
Actual build ... I will post in stages as I go through the model ..
The manual starts with the bottom wing. It has separate servos for each aileron and screwed down plates to hold the servo's.
First is to complete the hingeing of the ailerons .... manual shows them in place, moved and CA dropped in to set the hinges in place. Well I tried it that way and nearly lost a couple of hinges inside wing where they weren't trapped enough. So I did it my usual way .. glue into one side and then offer up and glue other ... That way I could have the hinges halved correctly.
TIP : when you glue to one side ... get a marker pen and make a dot in line with the hinge - so you have a marker to tell you where it is when closed up in place !
Once they are in place it's move on to the servo mounts ... TAKE CARE removing these .. they are held in place by clear tape on one corner - if you just pull it away - you can split the covering ...
First you have to choose the right size Triangle mounts and then CA these into the holes provided.
TIP : Make sure you allow for the servo grommets or other that you may use .. the slot in the plate for the arm to come through is a bit close to the servo and arm may foul top edge.
Second : Corona 929 Metal geared that I am fitting are too long and have an overhang at the back end .. this fouls the wing mount and I had to use 2 layers of servo tape to get clearance ...
The triangles to mount the servos are not in my opinion strong enough to put up with hard flying as I intend .. so I double mounted using those + servo tape to be sure.
TIP : take a 1.5mm drill and drill those triangles to take your servo screws .. even then when installing screws - the triangles came of the plate ...
Take real care when fitting the plates and their screws ... I would suggest driiling pilot holes in the small wing lugs that screws bite into ...
To get your servo leads through the wing ribs - they have provided threads that are fixed by small cards under the plates ... and after you cut at the dots in centre panel .. bit of clear tape to connect lead and thread ... carefully pull through..
Servos mounted ... onto the horns. On first inspection of the ailerons - you can see the pin-pricks made by factory. At first they appear 90 deg's out ... but later you realise that the interlink horn for top / bottom ailerons are mounted in line with servo ..
The servo rods are too long as supplied and the keepers are difficult to use. So I solved both problems in one move - I used Z bends in rod ends ... and clevis other end for adjustment.
I like that horns are more traditional with screws through to backing plates - instead of the usual chinese glued on type.
The rods are of sufficient diameter to be stiff and not flex.
TIP : If you are going to use separate Rx points for the aileron servos as I am ... then with marker pen - note the Rx # next to the lead for future reference ...
Before moving on to cabane /interplane struts ... use of the Iron to remove wrinkles, tack down loose film ends etc. and to tighten up what appears to be slack film.
Next post will be Top wing along with interplane struts / control linkages ...
Top wing and tail ...
The top wing is simple and only really needs ailerons fitted ... same system as bottom wing. Then control horns fitted making sure in line with bottom wing links.
Not a lot to report on that !!
Thew next step is to the tail end - this needs to be sorted before alignment of the two wings ... but needs bottom wing to check setting of tail.
The fuselage is already slotted for the tail feathers and the manual is not too clear abouit making sure of 1 step before another !! I made the mistake of setting elevator hinges BEFORE fitting joiner ... OOOOPS !
THIS must be done before hingeing !! :
Once that's done - you slit the covering of fuselage and slide the horizontal in as fgar as it will go ... a LONG way ! I drew a centre line along the uncovered part of horizontal stab so I could see it via the vertical slot ....
Here you can just make out the balsa insert that goes in behind the horizontal stab ... if you cannot find it - it's in one of the small bags !
When fitting the balsa piece - and rudder ... make sure they are aligned with fuselage parts flush !
To make sure i had tail aligned well - is nice as the bottom wing is flat, without dihedral ... so a good flat floor with bottom wing in place .. lay model on belly and then measure height of tail stab each side from floor, to wing tips etc. When good - run CA via the joint - it wicks in nicely. I also dropped it in via the vertiocal stab slot ....
Next I decided to fit the tail wheel ... but the screws supplied were useless as the heads were solid without cross point slots .. rading my servo parts draw yielded suitable self-tappers.
This uses an alloy U bracket to trap the wire to steer ... not a system I like but I decided to go with it.
I prefer a rubber band shock absorbing link saving the rudder from direct shock / damage,.
I then removed bottom wing and mounted the main wheels ....
The underside of fuselage follows the pin pricked hole indicators ...
The plywood plate under the covering is drilled ready to take the bolts, with captive nuts already fitted. All you need do is place bolts through U/C bracket ... screw into fuselage to captive nuts ... 5 mins and done ...
Then it's axle bolts ... tube, wheel and the spats ....
(note the wheels have the centre boss INSIDE to separate wheel away from bracket and allow spats in ...
One point that I found ... the slot is supposed to be wide enough to slide around the securing nut ... it's not ! I split one spat fitting it ... finding out.
The fixing holes are marked on the spats - but they do not match the fixing plate. Initially they appear at strange angle - but note the model sits at typical nose up tail-dragger angle ... spats account for that.
Spats are off at moment while I repair the split one and drill out where the axle nut should slot in ...
Next post is setting up aileron links and radio ....
During this time hopefully postman will be carrying the motor I ordered for this model. Recc'd is 2830 180W 1000KV motor ... but talking to guy who's flown one - that will give sport flying only ... it really needs significantly more to be really interesting - so I've ordered 2836 300W 1100KV motor ...
Cheers ... Happy New Year ...
A very comprehensive assembly thread, Nigel, I'm enjoying your report. I would suggest that you replace the steel landing gear bolts with nylon ones, so that a rough landing will shear the bolts, rather than tear out the gear mount plate. I know that we, as experienced pilots, don't normally make rough landings, but every once in a while, things go sideways, and it happens. ;-)
You read my thoughts !! In fact I even considered the rubber band method which is even safer for the model. Two dowels passed through fuselage sides ... rubber bands from one .. under UC and up to other each side.
Back to building ....
Fitting radio and Lipo
The radio gear is catered for nicely ... a tray is already fitted in fuselage bay and I tried to dislodge by hand - but seems well glued in. It's cut to fit 9gr servos and that's what I did ... a metal gear Corona 929 for elevator and a 9gr plastic for rudder. (I was going to use a Metal gear as well - but I broke the tab on the servo case !! ... so had to use one of the others I have in the spares box ... )
Inside fuselage - I am a great believer in a more permanent and fixed style of servo connection - z bends. Leaving trim adjustment to the external link clevis.
The control rods in this model are well supported by running inside mounted tubes. There's no need to cut covering at rear of fuselage - which I did !! as you run control rods in the tubes and they pierce / exit through the covering ...
The rods lie to a natural offset in the bay and therefore servos should be fixed taking this into account, otherwise you will have binding ...
Trick which works nicely with these rods, they are black coated piano wire ... when positioned - a knife blade scraped across will mark through the black to the silver wire under ... giving you the 'bend' point for the z bend ...
I fitted the rods to 1 hole in from end on servos and surface horns .. knowing that this would be too much against manual advised movements. Idea to then use EPA to bring movement back to recc'd limits. I always then have extra if I want by upping EPA and not having to play with the model links ... using such holes as well kept rods as bind free as possible.
The battery bay is ahead of the U/C and has a nice pre-made door but no fastening for it. It has a front tab and needs a fixing at rear ... more on that later.
In the box you are provided with large foam pad ... plus a velcro battery strap ! Now that's a nice addition. But how to fix ? I decided to tie-wrap it to the frame inside fuselage ...
The battery space is cavernous to say the least and will cater for a larger pack as long as you do not increase length from a standard 2100 3S.
I then had to decide where to mount the ESC ... for now I have taped it to the side of battery compartment as the motor leads are quite short ... later I wil probably mount the ESC the other side of battery tray inside fuselage.
Rx ... you have so much space to choose for this I was stumped as to where ... in the end I did similar to ESFC and taped it temporarily to fuselage side where I can get to plug in Ch 1 and 6 - the ailerons.
The overall radio fitment was easy and only took a couple of hours to sort.
Then it was decals ............. and mount cowl properly ...
As to LiPo bay door .... in the pack is a system that uses a nut and bolt. Not exactly field friendly ... so I modified by using one part and a servo screw ... to create a locking tab.
Now she waits motor .... on this I made a mistake .. I ordered a Turnigy 2836 - but missed that it is a rear mount motor. This model has a framed motor mount that needs the motor inserted in behind firewall, shaft to go through a hole and mount screws either side to fix ... a front mount motor. So a new order today for a 2836 1000kV motor with front mount and 300W rated ... on a 3S pack.
Manual advises a 180W 2830 .. but talking to a guy who flew one on stock RTF 2830 as manual states - he reckoned it was a nice cruising sport flyer - but lacked oooomph to get into real aerobatics. i hope that the 300W motor will supply sufficient..... the model as per manual is 770grams AUW to fly ... giving me 177W / lb ...
Some will notice that Spats are still not fitted ..... I still have to repair the one I broke and then drill out the slot ... they will be fitted before maiden !!
Now I have to wait postman .................
I've got the Precision Aerobatics 40" span version of the Ultimate. This is also superlight construction, mine weighs in at 1089g, inc. a 3s, 2200 Lipo. (924g excluding battery). I'm guessing to come in at 770g this one must be a bit smaller?
Anyway, if it goes anything like the PA one you will have a ball. 177W/lb is roughly what mine is running at which is good for 3D work and unlimited vertical.
The World Models is :
Wing span : 36" / 910mm
Wing area : 440 sq.in / 28.4 sq dm
Flying weight : 27 oz / 770gr
Fuselage length : 38" / 970mm
Recc'd motor : KD 2830 180W, to turn 10x6 prop.
I'm still to weigh her as I haven't the motor yet. ut I expect her to be slightly over ... as I've never seen a model hit advertised weight !
I've just put her on the scales and get following :
Model + 2100 3S Turnigy LiPo (193gr) + spats (15gr) = 770gr
Motor coming is said to weigh 80gr .... so AUW is expected to hit ~850gr
I do have lighter and smaller LiPo in same 3S / C rating ...
This now gives ... 160W / lb .... that's assuming motor delivers that !
3D ? Not really my bag ... but aerobatics and throwing a model around the sky is ...
I forgot to mention in prev. posts that I was concerned about use of the cross point screws ... I slipped once or twice while tightening them and luckily didn't pierce the covering ...
So solution ? I have 450 helis and they have same thread size as these screws, but with Hex heads. So cabanes and interplane struts now have hex headed screws that driver doesn't slip out of now !
Not a necessary modification - just a personal one.
Really frustrated .... still waiting the motor for it .... no motor available locally ....
It's really terrible seeing it hanging there and no prop !
I have this plane and I love it.
Hope you'll get your motor soon. But the weather is terrible ! :concern:
Very nice build thread Nigel and a really nice plane too. I hope you get the power plant in it soon so we can see how it goes.
Does she fly nice ..... a real treat but Oh Dear ! That lite-ply is like brittle paper.
I flew with a fixed APC 10 x 6 prop.
See my Rebuild thread in general Electric section ....
Basically the colour scheme on a winter grey day was not a good idea. It's the stock Yellow scheme. I lost orientation on the downwind turn and in she went ... and the brittle flimsy structure just shattered.
You can see in the thread rebuild that she has been remade and I should not have that problem again of fragile front end.
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