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Dec 28, 2015, 06:54 AM
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Build Log

Hawker Sea Fury Reno Racer - "Riff Raff" (Rating 11/10 !!)

When Hobbyking/"Avios" made the Hawker Sea Fury they decided to make up a warbird camo version, but also the modern day modified Reno Racer version that is named "Riff Raff".
Seeing they were all on "Super Special" during the sales, I got one of the Riff Raff versions also!
It is quite a different looking plane.... basically very racey looking, lol.

Last edited by PeterVRC; Feb 03, 2016 at 07:35 AM.
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Dec 28, 2015, 07:02 AM
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Differences to the Camo version

There are only a few differences to the Camo version.

1) It does not have drop tanks - though the drop tank mechanism are still in the wing and work.

2) No rockets

3) Only the 4 blade propeller setup version

4) It uses a 400kv motor running on 6S instead of the 600kv running on 4S.

So it has a bit lower weight when empty (due to less items), and even though the 'raw numbers' for unloaded RPM of the 400kv motor on 6S is very close to the same as 600kv on 4S, it does actually have quite a bit more Power/RPM than the Camo version.
I have some 6S 4000mAH 30C batteries to use, and with those it runs at 37 Amps and 835 Watts for WOT on the ground.
The 4S Camo version only runs 37Amps also, but on 4S that is only 550 - 600 Watts.

Because it uses the same 4 bladed prop as the Camo version can use (and is supplied with too), I can see that the higher RPM/Power is probably not going to make it fly much faster really. Though that is yet to be seen and proven! But it is based on the way the Camo version hardly goes any faster from 22 Amps region to 35 Amps region used.
Maybe I will be surprised!!!?

A suggested improvement is to use the Dynam BF-109 3 bladed propeller and Spinner setup, which is larger and also more 'speed efficient' and thus does give more power AND better top speed - which is more suited to the Racer image!

The 6S 4000mAH 30C battery is 650g !!!
But this makes the AUW for flying pretty well identical to the Camo version.
It would have been nice/useful it if was 400g lighter AUW! So then it could go faster for sure!
Dec 28, 2015, 07:04 AM
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Extended hatch

Seeing I had already built up and 'improved' the Camo version, I knew a bunch of things that would be best to do right away for the Racer!
The first was to extend the hatch so that you can have clear access to the battery area, and fit a Velcro 'floor' and Velcro straps.
I did it a fractionally different way, but for the same end result.
I made all cuts to be along the 'edges' of the checker patterns.

Dec 28, 2015, 07:06 AM
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Tail Wheel Mod

Same again as per the Camo version....
The tail-wheel is an Achille's Wheel (err, Heel) of the Avios Sea Fury. It is weak and it WILL break off. Thus it needs that mod to give it a metal pin.
For the Racer I did this BEFORE it gets a chance to break!

Dec 28, 2015, 07:09 AM
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Main gear mods - more Rake

And again, as per the Camo version.... the Sea Fury needs more RAKE - like all warbirds do really.

Seeing I knew how to do it all, I did the same. But I did not change to larger wheels this time.
Maybe I will change the wheels later on once I find the stock small fat wheels are an issue on grass!

For the Racer, I replaced the foam 'Retract covers" which are flimsy and annoying - glues on normally. I decided to make some thin Basswood Ply ones, and screw them on - for future ease of removal and access to the retracts.
They came out very nice and are way better than the stock foam bits!

Dec 28, 2015, 07:11 AM
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Ready to fly

All finished, set up, tested... and ready to fly!
Hopefully tomorrow.

I guess all that I expect is that it WILL fly totally fine, as per the Camo version does. And hopefully quite a bit faster! So that it looks like a Reno Racer!
But I am also expecting I will need to change the propeller to that Dynam BF-109 one, to really get a better top speed and for no extra Power used also, seeing it is more speed efficient.

Dec 29, 2015, 07:50 AM
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Maiden Flight Video

The Maiden Flight all went fine. It flew identically to the Camo version - no faster than that either.
The Small stock wheels made grass taxiing more marginal than the larger FMS wheels on my Camo version, so I should change to using those on the Racer too.

Hawker Sea Fury - Avios 1200mm "Riff Raff" Racer - Maiden Flight (19 min 59 sec)
Dec 31, 2015, 08:13 PM
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Batteries and CofG Balancing

My 6S 4000mAH 30C batteries balance out the Riff Raff ALMOST perfectly, with the battery up against the firewall. It really needs about 10g of weight added at the firewall to get the perfect balance point.

My 6S 3600mAH 30C batteries need 80g of added weight at the firewall.....

My 6S 3000mAh 30C batteries need a bit over 140g of added weight at the firewall....

Dec 31, 2015, 08:23 PM
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Broken Propeller Hub

Seeing I only did the Landing Gear Rake mod on the Riff Raff Racer, and did NOT change the wheels to the 68mm FMS ones, it is still only a fairly marginal amount of nose-over safety!
The SMALL and FAT stock wheels are terrible on grass.... too small to turn freely, and too fat to 'cut through' the grass 'jungle' !

You have to be quite careful when taxiing across the grass.
You also need to be VERY (as it turns out!!) careful about the take-off procedure!

Because the wheels have a lot of drag, even when the plane is running across the grass for a take-off, their drag is pulling "rearwards" and thus it rotates the fuselage nose downwards. To combat this you need to start with Full Up Elevator for Taxiing and the initial move to a take-off run speed, and then REDUCE the Up Elevator as it gains speed so that it does not LEAP into the air too soon! You need SOME small level of Up Elevator for the whole take-off run and process, or else it will head to nose down at the high speed!
Keeping the plane fuselage dead level, on two wheels as it gains speed, needs just the right amount of Up Elevator maintained!

This morning I FORGOT about that, and pretty well rolled off the Up Elevator totally - plus the Sea Fury ran into some thicker grass area(!!) - so that all added up to a High Speed Nose-over!! And the Propeller and Hub were not happy about that!!

The Hub fractured badly - a write-off.
The Blades were all OK....

I better sort out the Dynam 3 blade setup as soon as possible too!
Plus try some two blade props.... No Hub... Cheaper... Faster....

Jan 02, 2016, 03:14 AM
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Let's go FASTER !!!

In the interest of having a RACER and not a "plain Sea Fury show poney" (!!!), I got out some new props to try in the Need For Speed!!

I had two main propellers to test (though had about 4 types I could have tried):

14 x 6
14 x 10

The main reason I chose 14", rather than the 13" ones I had, is that 13" just looks too small. These aircraft types had BIG propellers - big diameters. Even the stock 4-5 blade looks one inch too small.

First I tried a 6S 3000mAH 20C battery.
At 20C and with a lowish Capacity, that will impede the power levels because of the higher Internal Resistance of the battery which then means the Voltage at the Motor is lower than for a higher C and/or Capacity battery.

14 x 6 22.0 Volts, 24 Amps, 528 Watts

14 x 10 21.7 Volts, 29.1 Amps, 631 Watts

These numbers are WAY under the stock 4 and 5 blade numbers! But note, the NUMBER is not all that counts....
The 14x6 is still likely to be a bit faster than the stock 4 - 5 blade. This is because the Pitch is the same, and that largely sets the distance travelled, thus airspeed, per RPM. But the blade area is also lower, even at 14", thus it has less 'solid bite' - which gives a trade off between gaining some more airspeed capability, via an RPM gain from that lesser area and lower loading aspect, but less 'traction' which only really matters under loads... such as climbing, but no real issue to level flight (racing).
This speed difference, whether it does come out a bit faster, or the same, or a bit slower(?), will be interesting to see....

14 x 10 21.7 Volts 29.1 Amps, 631 Watts

Still way under the stock 4 - 5 blade numbers! But this time we gain PITCH! A lot more Pitch.... less blade area total, which is unimportant to level flight... so it should make for a higher Airspeed, all whilst being that much lower Power total anyway!
Again, it will be interesting to see in flight....

6S 3600mAH 30C
A more capable battery, due to higher Capacity (lower IR) plus the higher C also (again lower IR).... but note that the higher C is also largely just what a higher Capacity 'creates' anyway!
14 x 6, 23.3v, 29.6 Amps, 690 Watts

Note how the larger Capacity, Higher C, battery maintains higher volts which then create higher Amps, and Power is Volts times Amps - which both those number rose, and thus gives a 'double whammy' in total Power gain!
Also note it could maintain OVER the 22.2V 'base' voltage of the battery - this shows the battery was driving this Power level without any undue stress - versus the 3000mAH 20C WAS under stress, seeing it could not hold that 22.2V level.
Being a 'fixed' Static test case, the RPM must be higher to cause the higher Load which demanded that higher power.
If the load was not higher, the numbers would remain as per the weaker battery. Higher Load in a fixed test case can only come via higher RPM. And the same in flight.... this battery would fly it faster than the weaker battery. (sounds simple common sense anyway huh?).

14 x 10, 23.4V, 33.6 Amps, 786 Watts
The numbers are rising, and close to the stock 4 bladed prop level now! But note, this 10" Pitch propeller will be propelling(!) the plane along much faster than the stock 6" Pitch. Once again, the lower blade area will mean it is not as tractable under loads, but that is unimportant in a fast plane!

6S 3600mAH 30C
4 Blade Stock
22.9 volts, 37.1 Amps, 851 Watts
5 blade stock
22.6 Volts, 42.6 Amps, 971 Watts (!!!)

ALL of those above numbers will quite dramatically REDUCE when the plane is moving and the propeller is greatly unloaded due to that!!
The stock 4 blade, 4S Camo version, with a 4S 4400mAH 65C battery, is 40 Amps Static, but does not go over 24 Amps even at WOT when just "flying around". But if you do go vertical and have it "hang off the prop" - which is the most load you can get in the air - it moves to a bit above the 35 Amps region THEN. But that is a very unusual situation that you would never really encounter in flying a Warbird to scale. Even a typical steep climb would not hit 30 Amps really.
So you can effectively take Static ground tests and divide the numbers down to just 60% region or so.... for the maximums you should really ever hit.

Larger Capacity batteries will have even higher Capability - due to their Lower IR, which then means higher Voltages reach the motor.
eg 4000mAH.... 5000mAH....
Probably something like 5 Amps more at 4000mAH, then another 5 Amps more at 5000mAH. But that is a very rough guide which the battery C Rating will also affect.

At the weight that 6S batteries are, you would not really want, or need, to go over 4000mAH.... and even 3600mAH is adequate.
3000mAH, even at higher C levels, would be more marginal and for long battery life I would stay at 3600mAH 30C at least.
But I guess if you REALLY want to go FASTEST..... you would push up the numbers via that 5000mAH size! The plane would carry and fly that fine still.... but it would really be much more of a point and shoot racer! The Power level at 5000mAH with a 2 blade 10" pitch would probably still not exceed what the stock 5 blade prop can run out to anyway.

Airspeed indicator:
I guess I really need to make some setup to fit my Telemetry Airspeed system to the Riff Raff!! Not GPS based, but Pitot Tube based (true AIR speed).
I have to see if I can add that without messing up the plane's great finish! The Pitot Tube COULD be put out on the wing where the scale one goes! But running the silicon tubing back to the fuselage - or mounting the main sensor unit (in the wing?) - would be the cause of 'hacking' to be required.
I will check out how to fit that because it is virtually a "must have" thing to test and verify the results! (or a Radar Gun??)

To finish it off - for now - I got my old Starmax SBach 342 1400mm spinner that I had kept in a box, so I tested its fit - which was very good as it turned out - and then I sprayed it gloss black!! The Diameter is a BIT small, but it is acceptable. And it is quite long and VERY POINTY, so that suits a "racing" look, LOL.
I do have a larger 90mm nylon Spinner on its way, and that is a much better size to suit the Sea Fury! Not as pointy though!!

Jan 02, 2016, 03:18 AM
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Airspeed system installation

After a bit of investigation of the Wing, I decided to pry off the Spar/Wiring foam cover strips they use. It was nNice to find an 8mm spar in there, which runs all the way to the Wing Tip! No wonder the wing is so solid... rigid!

I cut the section/length of the cover strip that I wanted for fitting the Pitot Tube and Sensor out in the Wing - and it all worked out great really!

I pulled through another servo lead, for the Airspeed sensor unit SBUS connection.

I drilled a 4mm hole into the stock Pitot Tube Mount and ran the N2 Industries Pitot Tube out through that. It needed a "collar" to bridge the 4mm Pitot into the 5mm plastic mount they have there in stock form, and this keeps it all solid in there - but still all easily removable!

I wanted the sensor near the Pitot Tube to keep the silicone pressure lines as short as possible.
The Wing(s) are so heavy that the weight of the Airspeed stuff out on one Wing will be insignificant in lateral balance anyway. Or at worst I can add a bit of weight into the other Wing Tip.....

I cut the foam cover panels so that I could re-glue on the spar cover section, but leave the forwards sections (pieces) as separate, so that I can just tape those down and give easy access to the Airspeed stuff - to remove it for use in other aircraft!

So after about one hour it was all done!! Not too hard, and making good use of the stock Pitot Tube position and mounting hardware!
Will I do it for the other Camo version Sea Fury......???? (no real need)

Feb 03, 2016, 07:44 AM
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FMS 1400mm P-51 V7 Four Blade Prop/Spinner

This is much the same as per I have done for the Camo Sea Fury.....

The Avios Propeller HUB design is weak and dangerous! It is almost adequate for normal operations....
The way it is designed is terrible, though if it was made from CNC alloy it would be fine... but it is made from thin and brittle plastic!
My 5 blade Propeller/Hub on the Camo Sea Fury "Exploded" on the take-off run!! And numerous other owners have had their hubs explode - some in flight!

There is also rarely stock of the Avios parts, so even buying new Prop blades, Hubs, Spinners, is difficult.

Luckily the FMS 1400mm series P-51 Propeller, Hub, Spinner, setup works great on the Sea Fury! This is only a FOUR blade setup, but that is what the Riff Raff uses anyway.
Their prop is a 14" x 8", so that is 1" larger than the stock Avios one - but it looks great and suits the plane well. The stock propeller is too small in diameter, for scale, anyway.

There is one issue with using the FMS setup... the backplate is "thick" and then there is not enough shaft adaptor to come through and put a nut on.
The way it faces onto the shaft adaptor also means the whole Spinner is 'out the front' of the Sea Fury Cowl... but their Spinner should run INTO the cowling some amount.

Luckily there is an easy enough fix for this!
The FMS Spinner Backplate can be dremeled so that it is effectively 'thinner', and this makes the Spinner move rearwards and into the cowling, whilst then giving enough thread out the front to do the nut up properly!
The end result is excellent!!

Flying with the FMS prop pretty much gives the same Power/Amp numbers as the stock 4 blade prop setup, for all 'normal' flying cases. Level flight....
But it can drive the plane to a bit faster top speed too.

When the plane calls upon more thrust, such as in a climb, the greater diameter and blade area of the FMS means more Load and more "Pulling" power... so the Power/Amps go up... but you are getting that stronger pulling power then.

The maximum load a plane can have is when it is not moving and the propeller is then trying it hardest to pull itself forwards, but it can't. This occurs on the ground when static testing the setup. In almost all other times in flight, the plane is moving and thus the propeller is not 'fighting' a losing battle, so there is less load and thus less Power/Amps. But there is one case in flight where it can match the static test high numbers.... that is if the plane flies upwards, say vertically, and then STOPS because it does not have the thrust to overcome its AUW. Then it is exactly as per a static ground test, and thus the numbers are maximums.
Mind you, if it falls down BACKWARDS against the prop drive, then the numbers will go even higher!

The fact that the FMS has the larger diameter and area means it can 'power' the plane stronger, at that higher Amps cost too of course. But it means you can do bigger 'climbs', such as for larger loops, longer steep climbs etc.

All in all the FMS setup looks really great and gives you more Power IF it is called upon.
It is also a very strong design... completely safe and reliable!!....easy to buy from many sources...
Who would want a prop/hub exploding IN FLIGHT!!??? Like the stock ones can!

The 14" x 10" TWO bladed prop flies the Riff Raff a BIT faster. It can do 140kph. With the FMS four blade it can only hit 133kph, which is faster than the stock 4 blade at 122kph approx. So if you want to go the FASTEST, you still want to use the two blade prop... or a two blade with even more pitch(!).
But the FMS four blade LOOKS AWESOME, so I am opting to sue it just for that reason alone(!!), and 133kph region is fast enough really!

Feb 03, 2016, 07:53 AM
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Motor mount comes loose - and a fix for that

I noted that the motor, prop, spinner of, my Riff Raff could "move" - that was because the motor mount now had slop in it.
This happens is most foamies sooner or later. The way they 'clamp' a firewall, motor mount, in between foam means if/when the foam gets compressed over time, or from accidents, then the firewall is not held firmly anymore.

A quick fix I often use is to epoxy it all, so it fills the gaps that the compressed foam created. This works OK some times....
But in this case doing that didn't last long at all!

The next thing to do is add extra firewall "supports". Such as, like I did in this case, adding another plate/"firewall" after the foam at the rear end of the stock firewall, and then clamp the stock firewall to this added firewall.
So basically I added a plate of 2.5mm beech 5 ply into the battery area, against the foam 'firewall' and then ran two 5mm bolts from the motor mount and back into this new firewall.
This clamps the stock firewall rearwards, and it made it all rock solid again.
Hopefully it lasts long term!


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