WR Zerstorer Build

[Declan]

Finally manged to clear the table for my next build! From what I've read on the forum this kit is going to be a fantastic kit.  This will be my build log of the Warbird Replicas Me110 Zerstorer which is one of my favourite aircraft from WW2.  There are quite a few being built already after the latest production run so I'll be looking forward to seeing the various paint schemes applied.  

 

[Declan]

Day one of the build.  Maybe the best day?  Unrestrained potentiality before any mistakes or compromises.

 

[Declan]

I got a fair bit done yesterday.  This is what happens when you get older and no longer go out for NYE!  Going to press on with the fuselage today and hopefully get it more or less assembled.  I've a little bit of sanding to do on the control surfaces and tail fins.  I also need to fix the leading edge to the horizontal stabilzer.

I'll be using this build to test out coverings for my FW190 build.  I have done brown paper covering on a model before and I'm not going to use that on this one.  It was perferctly good but I'd like to test out some new methods/products.  For the main and sheeted areas I will use EzeKote and glass cloth.  I've done cloth and resin in the past but doing this with a water based product is a first for me.  For the open control surfaces I will be experimenting with polyester dress lining fabric.  There is a guy on YouTube, Mark Croucher I believe, who has been doing this and it seems very good.  Cheap to buy, easy to get hold of and goes on well.

 

 

[Declan]

Didn't get as much done yesterday on the fuselage as I'd hoped.  The weather is good today so flying instead of building.  Just waiting for batteries to charge.  I was having difficulty assembling the fuselage but was having a stupid moment.  Once I realised that the central crutch is assembled with the formers from the shoulder down the sides and central crutch went together like a dream, the fit was superb!  I also wasted a fair amount of time bending the tailwheel wire.  I don't have a great setup for bending in the office and I couldn't get it bent just the way I wanted.  It would have been fine but I'd never have been happy with it so I will swap it out for a Dubro scale tailwheel assembly that I already have.  I'll leave it free turning and it should be fine.  I also ordered my polyester for the control surfaces.

 

 

[Declan]

I've finished the main basic shaping on the front lower nose section.  I will not do any more until I've fitted the nose.  I need to make a descision on where the batteries are going to go and do some general balancing of the model.  The top foam section is trapped under the canopy so I might cut this and join the offcut to the nose section.  This would make a nice removable piece.  Alternatively, I could cut the nose section in half separating top and bottom.  That would match the real life aeroplane.  I'm in a bit of a catch 22 situation as I cannot really plan anthing until I have my motors fitted and my batteries in hand to have a play around with them.  My main aim is to keep field operations as simple as possible with as few removable surfaces as necessary.  I'll need to do a bit of thinking on that one one after I'm further along with the build.  

The tailwheel has been installed and I think it looks nice.

Edited January 2 by Declan

[Eric Robson]

Hi Declan, I've made the nose detachable on mine. I want to try various battery combinations, if it works with the nose mounted battery I will fasten the nacelles permanently without hatches, if not the nose will be glued on. 

I lined up the nose former and drilled two 4mm holes through, two male 4mm bullet connectors were epoxied into the nose cone these hold OK into the wood. If over time the wood wears I would fit female connectors into the fuselage. I made a vinyl mask for the shark teeth but on removing it ,it left a sticky deposit which became impossible to remove without smudging the white 

[Declan]

1 hour ago, Eric Robson said:

I've made the nose detachable on mine. I want to try various battery combinations, if it works with the nose mounted battery I will fasten the nacelles permanently without hatches, if not the nose will be glued on. 

Eric,

Wow you're realy making great progress and it looks really good!  I am someway behind you.  I'd be very interested to hear how the model balances when you put the batteries in.  George at 4Max has advised on the power setup the same as for the Tony Nijhaus 72" Mosquito which is convenient as I can reference the size and weight of the batteries for that setup.   I'm thinking of both batteries stacked in the nose as in your design. 

Now that I've constructed the rear control surfaces they are quite small.  I've decided to go with micro servos which should be strong enough.  I did put this up on the thread a couple of weeks ago.  After speaking with Richard about the CofG of the model I think I will have plenty of wiggle room for my servos in the tailplane.  So your balancing of the model will be of great interest to me.  I've made up my y harnesses for the servo wires and soldered the joints.  I can now finish the bottom of the fuselage as there is nothing else I need to get in there.

 

[Declan]

Ok, so after some inspiriation from Eric I've added a battery tray.  I used the 4Max batteries that I already have which are the same width and height but about 20mm shorter in length so they work perfectly for sizing up the tray.   I cannot get the batteries any further forward in the model so I hope it balances out!  Unless I turn it into a nightfigher and make the antennae out of lead...... Once the tray has set I will set about making the fixing for the nose section to make it easily removable. 

I've also glued the bottom foam deck in place and that is now setting also.  Idid put some 1/4" stringers as per the plan along the length of the fuselage.   

 

 

[Declan]

After a good day in the workshop I've more or less got the front of the fuselage sorted.  I've added the four guns to the former F1A with a couple of small spacers to align the dowelling rods for the gun barrels.  I will cut them to length to match the different protrusions from the full size aeroplane.  I have also added a plate to the bottom of the former and put another small plate at 90 degrees to this on the bottom of the battery tray.  This gives me a positive ledge to engage former F1A on a regular basis while installing/removing the nose cone.  The top of F1A is pinched to former F1 by means of a threaded rod epoxied into one of the gun barrels.  This will be the 2nd longest gun barrel.  I will install a pronged tee nut on the rear of former F1 for this to screw into.  This should allow easy and quick changing batteries at the field.  All I need to do now is cut the holes for the guns to protrude out of the plastic moulding and then epoxy the moulding to F1A.  I will also trim and epoxy the moulding to the gun barrel spacers for extra rigidity.  After that is done I will be able to sand the front section of the fuselage to line up with the fitted moulding.

[RICHARD WILLS]

I think it's good to experiment a little bit . Minor modifications do interest me because we never really know if the first decisions were the best . 

Batteries in the nose verses one in each nacelle for example . I think they will both balance ok . The only thing to watch out for is what I call "the nod ".

That is the violent down force on the point of touch down which will act on the nose or the nacelle where they meet the wing . 

You can imagine that with the weight of one or two 12oz packs trying to hit the floor is considerable when the wheels hit terra firma and jolt the model to a halt from its decent.

With the doublers in the kit , I dont see a problem though . A 120FS and 12oz of fuel would create a similar load on a 72" single engine sports model .

Great foot wear in the post above . You will find Declan , that the  lads on here are very interested in the background of your shots . 

Perhaps we all watch too many detective programmes ?😁

 

 

[Declan]

10 hours ago, RICHARD WILLS said:

Batteries in the nose verses one in each nacelle for example . I think they will both balance ok

TBH I don't know as yet where I'm putting the batteries.  Until I have it built and all my radio gear fitted I'm kind of working in the dark a little.  I've done the front battery mount more as an option if needed so to speak.  I'll be very interested in seeing how Eric's model balances out.  I hope the model will be fine with the weight of the batteries up front.  My tray is fixed to the front former and the side doublers so I would imagine any flexing load would be distributed along the lenth of the sides.  As you say a nitro engine up front would put some stress on the airframe along with the fuel tank.

 

Managed to ge the nacelles main components glued together ready for assembly on the next session.  I like getting to the point where I've emptied the box of all the bits supplied with the kit!

 

 

[Chris Walby]

18 hours ago, RICHARD WILLS said:

I think it's good to experiment a little bit . Minor modifications do interest me because we never really know if the first decisions were the best . 

Batteries in the nose verses one in each nacelle for example . I think they will both balance ok . The only thing to watch out for is what I call "the nod ".

That is the violent down force on the point of touch down which will act on the nose or the nacelle where they meet the wing . 

You can imagine that with the weight of one or two 12oz packs trying to hit the floor is considerable when the wheels hit terra firma and jolt the model to a halt from its decent.

With the doublers in the kit , I dont see a problem though . A 120FS and 12oz of fuel would create a similar load on a 72" single engine sports model .

Great foot wear in the post above . You will find Declan , that the  lads on here are very interested in the background of your shots . 

Perhaps we all watch too many detective programmes ?😁

 

 

 

IMO its worth bearing in mind where the weight is and the load it imposes on the airframe. If all of the weight is concentrated in the nacelle then the landing load  is absorbed within the nacelle, where as if there is a lot of weight in the nose, then load will be transferred along the wing and through the fuselage.

 

With IC you don't have a choice of remote tanks (they don't weigh that much anyway), but there is the advantage of weight where you need it all within the nacelle. My foam P38 has a single battery in the nose and its very noticeable the bending moment it exerts on the airframe although landing is mitigated by the nosewheel UC.

 

PS there is of course the never ending debate over extended ESC's leads and choice of ESC manufacturer (OK for you, but others might not be) by a subtle change from ESC location from the nacelle to the fuselage. Lastly is a point of safety as nacelle batteries could be connected from behind the prop arc where as the final connection puts you directly in front of a twin dicer (I have armed my BH Mossie with the UC retracted so that if it did make a bid for freedom its would at least de-blade the props before getting hold of me!). Remember an IC engine can be stalled in one revolution, but electric will just keeping going until commanded to stop or the motor/esc burn out. 

[Ron Gray]

I had the batteries (4s 3700mAh) mounted in the nacelles on my last WR 110 and this gave me the correct C of G with no added weight. I will be doing exactly the same when (when?) I get around to building this one. I agree with Chris that the landing loads are far better distributed through the airframe with them in the nacelles, I also agree that it’s much safer (arming) with them in the nacelles.

Edited January 5 by Ron Gray

[RICHARD WILLS]

A good point about safety Chris . The nose mounted battery does leave you rather vulnerable to a pair of "bacon slicers " .

Having had to deal with a very nasty electric accidental start up on a fellow club member last year , I can can honestly say that I view the risk as very real !

[leccyflyer]

8 hours ago, Ron Gray said:

I had the batteries (4s 3700mAh) mounted in the nacelles on my last WR 110 and this gave me the correct C of G with no added weight. I will be doing exactly the same when (when?) I get around to building this one. I agree with Chris that the landing loads are far better distributed through the airframe with them in the nacelles, I also agree that it’s much safer (arming) with them in the nacelles.

Ron -  although you had the batteries in the nacelles, did you still have them in parallel, feeding both motors, rather than one motor each?

[Ron Gray]

One motor each Brian. 

[Chris Walby]

In reality it makes no difference if its one battery (or two in parallel) or two batteries individually feed each ESC the failure mode of the ESC operating on LVC is the same.

 

With one lipo or two in parallel.

Lipos very rarely go open circuit, normally one cell voltage will collapse causing a ESC to go into LVC, the twist is that the reduced total current will probably mean that the other ESC does not go in to LVC. Lots of different ESC's out there and how they detect and announce LVC. Some pulse, some back off and then recover and some reduce power and latch until the input connection is cycled.

 

It raises the question of having a separate RX battery/UBEC and then another battery for those that like to run their retracts on a separate battery as well!

 

I will go for one lipo in each nacelle and the 4Max approach with a UBEC off one lipo supplying both RX and retracts (the retracts probably have current limit cut off, failing that a UBEC that can handle the current of a stalled retract/servo). Its not like it will be consuming a lot of power with the servos or retracts and avoids a problem where one ESC arms at a different time to the other.

[leccyflyer]

I was talking more about reducing the possibility of having one ESC cutting power to one motor, due to going to LVC, thereby causing asymmetric thrust and negating one of the benefits of electric power in a twin. In my twins the wiring loom is set up in parallel to reduce that possibility.  Different horses for different courses I guess.

[Chris Walby]

5 minutes ago, leccyflyer said:

I was talking more about reducing the possibility of having one ESC cutting power to one motor, due to going to LVC, thereby causing asymmetric thrust and negating one of the benefits of electric power in a twin. In my twins the wiring loom is set up in parallel to reduce that possibility.  Different horses for different courses I guess.

My point is that in reality its not how it works with a single battery... or two in parallel as one battery will just mask the other until one ESC gets to LVC.

Been there and done that so I know what happens in reality. You could force the other ESC to back off to meet the one that has gone into LVC.. if you want.

 

It does not reduce the likelihood at all if you think about it and is of no benefit. The benefit of single battery is where its positioned for C of G like the PZ Mosquito, BH Mosquito, Fliteline P38 and OV10, but two of them have nosewheels. 

[Declan]

Ahh what is safe?  So if the model is correctly restrained, then it will not move when powered up.  I fear correctly restraining a model is being lost due to the reduction of glow power.  From my previous experience before my sebatical to this hobby you never started a glow engine unless the model was restrained based on best practice.  That's not to say one never 'broke the rules' so to speak but that would usually have been on a model/engine combo you were very familar with.  So in theory if the model is correctly restrained then the props scribe the same circle in the air and  are unable to move forwards irrespective of whether you are in front of them or behind them ?  Now if you are inserting batteries into an unrestrained model then yes, behind is more safer.  However, you cannot have your cake and eat it so to speak.  Either safety is the primary driver or it is not.  If you're advocating unrestrained startups then already one safety procedure has been abandoned?

 

Accidents ironically don't often happen when risk is percived to be high.  We usually make mistakes when we belive we are in a safe position and are complacent.  Best practice may reduce risk but it is often the risk that ultimately protects us as it keep us alert and paying attention.  

Edited January 5 by Declan

[leccyflyer]

I don't see anything about the model not being restrained and moving. The increased risk of a nose mounted lipo being referred to  would presumably come from making the connection from in front of the model and therefore being exposed to the twin prop arcs, without the model moving an inch.

[Ron Gray]

My 110 had a separate Rx battery and then another one for the sound system and retracts. From memory they were <1300mAh 3s.

 

The 110 also flies very well on one engine!

Edited January 5 by Ron Gray

[Declan]

1 hour ago, leccyflyer said:

I don't see anything about the model not being restrained and moving. The increased risk of a nose mounted lipo being referred to  would presumably come from making the connection from in front of the model and therefore being exposed to the twin prop arcs, without the model moving an inch.

Maybe I'm missing something or I haven't understood what's being said.  Lol, you might be agreeing with me but I'm not sure.  If the model is restrained the props swing in a fixed point in space.  Whether you are in front of them or behind them is irrelevant.  The nose fitting of the batteries would be further away from the props than the nacelles behind the props?  Looking at the plans it might be equidistant.  You can accidentally put your fingers in the prop from behind just as much as from in front? 

[Ron Gray]

1 hour ago, Ron Gray said:

My 110 had a separate Rx battery and then another one for the sound system and retracts. From memory they were <1300mAh 3s.

 

The 110 also flies very well on one engine!

I think I was wrong, the u/c had a separate, shared battery with the sound system, the Rx was powered off one of the motor batteries.

[leccyflyer]

From what I can see, your nose will be removable to fit the batteries and you will connect them up, with the nose off. I assume that you will be doing that from the front and you'll then have your hands within the plane of the prop arc. If the batteries were in the nacelles, accessed from the rear, you'd be making that connection behind the prop arcs and one at a time. The issue doesn't depend on the model being unrestrained and moving, it depends on the operator inadvertently moving their hands through the prop arc - which is more likely from the front of the model.