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Posted by Vortrog | Jan 01, 2020 @ 07:14 AM | 2,860 Views
NOTE:This post contains practices already known to experienced builders and is really a catalogue of my learning for reflection after I maiden to see if indeed performance of my model has improved.

Summary of Alterations from Original Build

Weight 4.2kg Empty (-200g)/ 4.55kg Fuelled
Wing Loading 105g/cm2 (24oz/sq.In) (-5g/cm2)
Prop Size 14x6 2-Blade APC
Flight Time TBC
Stall Speed 46km/hr / 48km/hr
Centre of Gravity 95mm

Control Throws
Ailerons Low 17 Degrees / 10% expo
Ailerons High 23 Degrees / 10% expo

Elevator High 10 Degrees / 20% expo Need higher rates
Elevator Low 28 Degrees / 50% Expo Need higher rates

Rudder High 25 Degrees / 30% Expo
Rudder Low 15 Degrees / 30% Expo

Flight Characteristics
TBC on maiden

Around 6 months ago I maidened my first ever complete RC model build. Despite being a good looking scale model it has many issues resulting from a lack of build experience.

Amoung these were:
Very high wing loading (heavy build, heavy tail resulting in 400grams of nose weight)
Sluggish aileron response and precision (belcrank setup lagged and had free movement)
Snakey ground handling (tailwheel excess play and wheel axle mating was loose)
Overheating (airflow)

During a test ans buddy box run with one of my mentors, we overflew her fuel tank, the motor cut out and i had to deadstick downwind in the outfield. The resulting damage was a smashed nose, and split and heavily damaged wing.

This blog is going to track my...Continue Reading
Posted by Vortrog | Dec 28, 2017 @ 10:24 PM | 13,901 Views
Summary of Model and as built conditions / settings

Build Type Plywood Frame / Balsa covered in 1/4 Oz Fibreglass and Autopaint
Wingspan 60.75Inc (1540mm)
Wing Area 642sq.Inch (4141.93sq.cm)
Weight 4.4kg Empty / 4.75kg Fuelled * note: you should be targetting a 4kg empty weight
Length 51.5Inch (130.81cm)
Engine OS 75AX
Motor Size Recommended .60 to .80 Actually used = 0.75
Prop Size 13x8 3-Blade Master Airscrew
Radio Spektrum 6 Channel
Battery Eneloop 5 cell 6V 2000mAh
Fuel Tank 12Oz (350ml)
Flight Time 8-10Mins
Stall Speed 47km/hr / 49km/hr
Centre of Gravity 95mm

Control Throws
Ailerons High 15Degrees / 10% expo
Ailerons Low 17 Degrees / 10% expo

Elevator High 10 Degrees / 20% expo Need higher rates
Elevator Low 28 Degrees / 50% Expo Need higher rates

Rudder High 25 Degrees / 30% Expo
Rudder Low 15 Degrees / 30% Expo

Flight Characteristics
- Extremely responsive to rudder. As a result, ensure for first flight rudder is perfectly centred and tailwheel is also set for straight travel. Will make for rolling liftoff if rudder is not centred prefectly.
- At this weight, must be flown fast.
- Rock solid in air at speed
- Stall is sudden with little warning
- Final flare cannot be held without stall.
- At this flying weight (4.5kg and above) and configuration will not loop at full throttle without dive first to gain speed.
- Will bounce back into air due to landing speed if not perfectly touched down
- high sink...Continue Reading
Posted by Vortrog | Jan 18, 2016 @ 08:51 PM | 4,923 Views
So, I flying friend crashed his Sbach 342 a few weeks ago and offered it to me for parts. The sad story of this is documented below (thanks to Tom Markwell for his video and donation):

151226 2 Sbach at PAC Now that's a write off if ever I've seen one (3 min 37 sec)


As my son refuses to fly my Sbach for fear of crashing it, I decided to rebuild the donated model for him.

See Below for images of the rebuild.

Stats on the rebuild:
Sessions: 4
Total time to build: 8 hours (excl glue drying time)

So, I was able to finish the job....inserted the original motor I had saved from my other Sbach 342, tested and balanced it all and was good to go.

The day before the maiden, I buddy boxed my son to trim everything up to my default settings and the motor refused to operate and the ESC wouldnt arm.
after some testing, I determined that the motor had crapped out and so I rushed out and bought a new one.
In a hurried rush to impress my flying colleagues with my rebuild skills and to show that Glue can really fly, I swapped out the engine and headed to the field without rebalancing my model. The result is below.

Hobbyking Sbach 342 1400mm Maiden after major repair - Jan16 (7 min 25 sec)
...Continue Reading
Posted by Vortrog | Jun 19, 2015 @ 12:20 AM | 4,538 Views
I have currently been flying my Sbach 342 on 'low' throws and enjoying Aerobatics, but want a bit more.
Ive tried Harriers and failed under low rates, and struggle to hold hovers.

So, I decided to put my Sbach on the bend to have a look.

I need to measure the actual deflection to compare with both the manual and FMS throws, but from memory, my low rates are about equal or slightly greater than the manual recommended throws of 25mm. I suspect I am in the 30mm range for the elevator....Continue Reading
Posted by Vortrog | Apr 14, 2015 @ 03:52 PM | 5,114 Views
After about 20 flights of my Sbach 342, a couple of hard tail first landings resulted in my tail wheel snapping off. I didn't realise until I got home and luckily one of my flying comrades found it for me on the field.
The wheel sleeve is nylon and there is only about 6mm2 of plastic holding your wheel to the bracket. It will inevitably shear off.
In order to fix or reinforce the wheel sleeve, ideally, it should be overclad with a lightweight metal casing OR replaced with a custom metal sleeve/bracket. As this is practically impossible to achieve, the next best thing is to use tensioned wire to 'pull' the sleeve and wheel bracket together and hot glue to encase the new composite reinforcement.
The next issue I need to address is reinforcing the rudder at the installation point for this tail wheel's control horns. That will be another post
Posted by Vortrog | Apr 07, 2015 @ 08:16 PM | 4,613 Views
A couple of weeks ago, I booked in an instructor from my club to undertake my MAAA Bronze Wings test.
On my practice battery, my elevator Potentiometer on my Spektrum Dx6i failed and locked my elevator in 100% down position.
After two inverted loops my Sbach342 came down hard in the only are in the entire field that had been mowed (the grass is typically 2m high!)
The result was below.
My repairs are chronicled below

I maidened it again last week, and passed my test on the weekend.
Posted by Vortrog | Mar 22, 2015 @ 05:34 PM | 4,066 Views
If you have some flying buddies, want some real skills testing of your flying skills, and you all have a model that flies well but sort-of-can-afford to lose it for a week with repairs, then you need to try some Streamer Combat.

We run this when we can, and this weekend we had a full crew taking part.

I use a Bixler 1.1 as the streamer tow...its low cost and can actually take impacts pretty well.

Our 'team' fly a variety of models, from profile 3D, the scale warbirds, but generally foamies under 1200mm. Ideally, 900mm to 1100mm is the perfect size as it can grab a streamer but still be controllable in the air. Anything smaller and I think it wont have the airflow to remain in control with a 3m streamer attached.

Anyway, heres a vide log of the weekend fun. We had one middair collision, but it was a bump only. All models came home safely out of the 5 chase planes and the tow.

Streamer Combat 150311 at Phoenix Model Aviators (3 min 43 sec)


150322 Streamer Combat 3 - Phoenix Model Aviators (1 min 41 sec)
...Continue Reading
Posted by Vortrog | Oct 12, 2014 @ 08:25 PM | 3,979 Views
DC Naza v3 Maiden... Sean Walk (2 min 50 sec)


Thanks to SCQuads for his video of our morning fly
Posted by Vortrog | Sep 22, 2014 @ 05:54 PM | 5,108 Views
TopRC FW190 PNF 1200mm owners, as part of your preflight checks....check your wing join seam with a little loading. (eg. face the model towards you, grab the leading edge of each wing and try to flex them gently up and inspect the load). Read below for why

To FW190 2The PNF kit comes with the wing already assembled which is great.

Recently though, the model has been acting erattically when banking hard or pulling out of dives or loops, fighting Aileron control until the model slowed down.
I fly the model 4S and really pull a lot of G's at high level. This and added to rough landing fields and (on occasion) loading other models on top of her (something you shouldn't do) means that those poor wings, despite being 6mm carbon rod reinforced, take a lot of punishment.

Ive also had a couple of landings where the gear just 'did the splits' and allowed the prop to strike resulting in a instant nose over. At first, I thought it was the crusher dust on the landing strip making the wheel slip outwards. I was wrong.

My original post here
https://www.rcgroups.com/forums/show....php?t=2250212

As a result of the suggestions, I found at least part of the problem. Can you see it?


HINT: The slight separation to the rear of the wing join gives it away.
Yes, my wings glue (clear gum type cement) has given in and is allowing the wings to flex up under load.

Here it is with a little wing loading


So, its time to reconnect the wings.
For this I chose hot glue, however I think the...Continue Reading
Posted by Vortrog | Sep 01, 2014 @ 04:01 PM | 4,574 Views
The small plastic batter hatch latch 'disappeared' on the weekend (shook off in flight...was lose from a couple of rough landings anyway) and so I came up with a solution.

I had a spare worm gear axle which due to its end cog, makes it perfect to finger screw into the cowl.


As a locking plate, I just flattened out the hook shown below on the right, and trimmed it back to size.


It takes more time obviously to unscrew and then open the hatch, but it is infinitely more rigid. The hook also already has a hole in it so no drilling required.

Finished product
...Continue Reading
Posted by Vortrog | Sep 01, 2014 @ 03:49 PM | 4,723 Views
Following my nasty nose in on the weekend as a result of a number of factors (not sure which one was the most critical) which included visual aspect recognition, I am in the process of trialling high visibility colour to the underside of the wing.
I am starting with just a yellow to the underside wingtips using acrylic art paint.
This is the paint used


I am hoping this will make it a little easier at long range to pick up if the model is turning away or turning towards me when sillhoutted against a bright sky.

End product. Airbrushing would have been sooo much nicer, but this will be effective. We shall see on the weekend.
This is with two coats. I have one more to do tonight to eliminate the blue still coming through from the base coat.

Posted by Vortrog | Aug 20, 2014 @ 05:51 PM | 5,007 Views
This post is to summarise solutions by others on the TopRC Fw190 thread, and demonstrate what it looks like. Plus some other tips that worked for me.

Under stock conditions, when your prop strikes the ground, the nut behind the spinner fan and the prop will automatically travel down the prop shaft.
If you are lucky, the prop will just seem loose, and some attention may be required to wind back the prop and fan and lock them back into place.
If you are unlucky, the fan and its nut will tighten itself so hard on the end of the prop shaft thread, that you cannot undo it without mechanical assistance. Moreso, the prop will now rub on the cowl which means you cant live with it anyway.

In this scenario, I was able to undo the fan and fan nut but clamping the end of the prop shaft with pliers and using brute force to undo it. The result however was to crush the thread at the end of the shaft making removal of the fan and fan nut impossible. Moreso, replacement of the prop and prop locking nut was also near impossible.

So, a recommended first up mod to the stock model when you receive it, is to get yourself a m4 nut (0.7 thread) and place it on the propeller shaft and wind it all the way down to the end of the thread. Then install a suitable washer BEFORE installing the Motor Fan and Fan nut. See below (sorry about the picture quality...looks like its from a soap opera!)


If you have already ruined the thread due to a prop strike, the following is a solution:
Get yourself a M4 0.7mm Thread Die.


They are around $6 to $8. better still borrow one like I did.
This will allow you to reshape the crushed thread without replacing the shaft (which usually means the motor)

As a backup, I ground a flat at the end of the shaft so I could grab it with pliers in future should I have any issues again.
Posted by Vortrog | Aug 05, 2014 @ 06:11 PM | 5,597 Views
Follow the success of a similar project, I have decided to share my experience with creating a similar system for my TopRC Fw190.

My previous project was for a Durafly A1 Skyraider 1100m, and considering how much smoother the Fw190 seems to fly, I am expecting this to also be a success.

What you need:
- a tin box or aluminium box or sheet (say .5mm). I found an old tin box and it is important that it is flat to reduce the amount of work you have to do.
- Tin snips (probably safer to use a blank sheet of ply with the metal over and a jigsaw) or you can manager with wire cutters.
- Pliers
- 1 Small bolt and nut (say 35mm long)
- Self adhesive Velcro (cut to the size of the camera)
- Hobbyking HD Wing Cam (SKU:A-CAM)
- Large Nail and some self tapping screws (to create the fixing hole)
- Some sandpaper of file (to remove sharp edges after completion)
- 90-100gram counterweight for the nose once fitted.

Build Process
To save you a lot of time, I have created a template you can print out in A4 to scale and cut out. I used cardboard to make this template, and it took me two attempts to get it right.
CLICK HERE FOR TEMPLATE


Test fitting the template

...Continue Reading
Posted by Vortrog | May 25, 2014 @ 05:44 AM | 6,103 Views
This mod requires 2-1/2" Dia. Treaded Lightweight Wheel (2), a craft knife and some patience.

Wheels Replacement and sequencer/wheel cover changes
You firstly need to remove the old wheels. Don't lose the E clips holding them on!

Once done, you need to put the new wheel in the wheel back and determine how much foam you need to cut. From memory, it is about 5mm.

I also needed to trim about 3mm off each of the sequencer doors.

And finally, to prevent the wheel covers grabbing grass, remove the leading edge of each of the wheel covers at 45 degrees from the wheel axle.

Put the new wheels on and test. Trim foam as required, then go again.

Hobbyking (TopRC) FW190 Gear Mod view and operation (0 min 23 sec)


The video above gives an indication of how much foam you have to chop out for the wheels to fit.

Raking the gear forward to prevent nose overs on grass
Lastly, to solve nose-overs, the gear needs to be raked forward.
To achieve this, I did this with 2 small rectangular pieces of balsa (5mm thick) stacked on top of each others at the rear of each gear. I also used slightly longer screws.
The reason balsa is a good choice is because it isn't rigid, so will absorb some of the landing shock.
Once screwed in, the balsa will compress some, but do not tighten too much. Once you get resistance from the screw, that will be all you need. It will seem a little wobbly to stress, but it actually works really well.




In the images above, you can see the second layer of...Continue Reading
Posted by Vortrog | May 21, 2014 @ 08:45 PM | 5,198 Views
Son:
- Currently (19 Aug 2014) flying Durafly A1 Skyraider and Durafly BF110
- Experience:
Axion TL3000 Micro - 3 months (8 Hours total flight time)
Skyraider 5 months (15 hours total flight time)
Archer 10 months (18 hours total flight time)
Bixler 1.1 (1 hour total flight time)
Durafly BF110 1200mm (2 hours total flight time)
Next Aircraft:
TBA

Myself:
- Curently flying TopRC FW190, Parkzone Archer and Bixler 1.1
- Experience:
Bixler 1.1, 12 months (10 hours total flight time)
Archer 5 months (3 hours total flight time)
TopRC FW190 1200mm (2 hours total flight time)
Next Aircraft:
TBA