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Mar 02, 2019, 09:59 AM
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Build Log

Fox 3000mm aerobatic Glider - FMS


I do already have the 2300mm FMS Fox Glider - which is a very good, well made, glider.....
I partly got the 3000mm version as that is more ;serious'... more capable.. plus uses the same 6S batteries that my 80mm EDF's use, so taking the Fox with them (EDFs) means that if I don't fly the jets as it is too windy, or some reason, then I can just fly the Fox - as gliders don't care too much about wind levels.
Of course I can just take it and fly it anytime also....

Near 6Kg AUW!! Wow.....
My 4m DG-808 (FlyFly... and broken for now!) is under 4Kg AUW ! But it is a performance thermaling glider... not aerobatic...

The FMS Fox got a lot of good reviews, and nothing seen to be negative about it. Too bad that doesn't always mean a lot anyway! But what can you stuff up on a 'simple glider' anyway??? Thus it should be good/fine.... and the FMS 2300mm version is, so...

Interesting is that is uses NO GLUE.. and NO SCREWS... to assemble it. It is all done via plastic keys parts and sprung clips to lock them into place. This makes transporting it easy (as easy as per any), but FAST EASY assembly at the flying field..... and to disassemble it and pack it up! This was another reason it seemed a good thing to have....

....
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Mar 02, 2019, 10:13 AM
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First things


The wings, tailplane, and tail end, all just 'clip in' to complete an aircraft. All the plastics that entails are quite robust and well thought out - but that is also where a lot of the weight comes from!
The Wing Spar is massive!! Woven carbon fiber, over 1m long and about 15mm diameter. (20mm?)

And it does all just click together fast and easily!

The Wing has fixed connectors that mate when the Wings are put on.
The Tail End you have to join two servo connectors and the fit the tail fuselage portion to the main fuselage portion.
The Tailplane keys in and locks, using a servo connector that is fixed in place so it makes that connection as you slide the Tailplane in.
I don't think I like the Servo Connector ideas at all, as they are not made for lots of plugging and unplugging so they would wear over time.

Then I found that my Tail End Servo Plugs were not tight 'safe' fits. One was so sloppy it could fall out on the slightest thing that made it do so!
Pushing the wiring into the fuselage caused this almost every time - and if it did not do that in view, clearly, who knows what it had done inside the fuselage? OR.... could do at any time, like when flying!!
So I cut those off and replaced the pair with a 6S JST connector set. That way they lock in when you join them up!
This issue is a serious/dangerous one, but apart from that it really is the best and closest to true PNF I have seen/had!

The ESC/Battery connector was XT60, so I changed those to my 6mm XT150 type.

I used an S6R (RX with Flight Controller) as the Stability and/or Auto Level (Angle Mode of Control) aspects might come in use....

The Wing lock releases are almost impossible to do single handedly, so I worked out using a rubber band is a good way to make that easier.

When I ran up the motor to check the blade balances, when I took it back inside I thought to check the motor screws/bolts and see how it was all done, and in case they needed Loctite or CA on them.
Three of the four motor screws were loose!
I took those all out and replaced them with Hex head bolts because the stock ones were Philips/Cross head types.
These mount the motor to the X mount and then another 4 long bolts fit that onto the large plastic motor mount. Those bolts were firm and they also sort of 'bind up' when done tighter, so they should not try to come out on their own anyway. I will check them in the future and if need be use some CA, because they are running through plastic on their way to the brass bushes/nuts they have. Loctite 'eats'/damages plastic, so that is no good to use for those!!

....
Mar 02, 2019, 10:21 AM
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TX programming


About two hours of setting it all up in OpenTX. To cover all items it has, and via Flight Modes so the Flight Controller stuff can be 'controlled'
/setup easier.
Then it was ready to fly.... but it was getting near dark, and still windy... so....
But if I had made it about 30mins (or more) earlier then it would have been viable to fly it.


When I picked it up I found it is very heavy!! A strain to hold up, and likely to be even more strain the 'throw' it adequately!!
And to make that worse, there is nowhere to hold it very well either!! It is very slippery, plus all very rounded and just nowhere to get a grip on it!
I doubt I could hand launch it successfully at all !!
Mar 02, 2019, 10:28 AM
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The Dolly


This meant I needed to find an alternative launch method, and seeing "CaptG" had made a dolly up, that looked to be the main good idea/method of how to make one up! So I used that as a basis for my own version - just a few improvements to aspects of it.....

It is near completed, but I need to find some different 'legs' and wheels for it. I used the set from the Ex Piper Cub 1400m, but they aren't happy with that 6Kg on them!! I will do that in the morning, and if the wind is OK I can take it out after lunch. BUT, the weather bureau says VERY STRONG WINDS and that means it is unlikely to be viable to fly it tomorrow. But I will see.....

Another option, instead of a Dolly, is to fit a Bungee Hook and then just use a bungee run from the ground. Seeing the Fox has a main centre wheel.
The bungee stuff is sort of as much volume/space needed to take it along also as a Dolly for it anyway, but it is more a matter of which way WORKS better/best.
So I will fit some form of a Bungee Hook to it. Probably a mounting plate so that a removable Bungee Hook can be bolted on when it is required. And left off when not being used.

----

Dolly done:
It has a few improvements over the CaptG version.

1) A full wheel lock 'bay' so the Fox cannot move forwards or rearwards. Otherwise it tries to move too easily.
2) Velcro straps to lock it down to the Dolly, so that it definitely stays put in place for sure!
3) The above is to make it a "Transport Dolly" also - transport, and assembly, disassembly..... on the Dolly.
4) Fixed large wheels. The axles are mounted into the sides of the base plate, to be super robust. Large wheels to deal with any grass you might fly from.

....
Last edited by PeterVRC; Mar 05, 2019 at 02:25 AM.
Mar 02, 2019, 10:39 AM
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Quality.... Issues....


All in all this FMS Fox is very well made. The foam is HEFTY.... but thus heavy too! It is way thicker and stronger than the 2300mm version.
This thing could take quite a big beating before it did damage!

The connector plugs for the Wings seem good.
The Tailplane and Tail End ones are a BAD idea!! More so in my case as one was rubbish!
The Tail End ones are best replaced for sure!!
The Tailplane one, seeing it is past of the keying in system, it would be hard to replace with anything to operate that easy fitting system still. But I think I will just leave the Tailplane fitted to the Tail End always anyway......

The foam is the 'older' style of EPO... a bit rough in cell size. Versus many EDF's have the newer high density type. But if they used that it would be even heavier, so....

The decals are nicely done.
I will WBPU the entire Fox at some stage (reasonably soon), partly to lock down all the decals whilst also giving it some protection and ease to clean.

The motor looks hefty and thus adequate size/quality. The ESC looks adequate.
The Servos are all large, but I didn't check if they are Digital or Analogue - they sounded Analogue to me I guess. And I know they are all Metal Gear. (FMS says).

So all in all it is a very well made Glider. Probably a bit high in cost for what it is, but not too far amiss.
I did buy it from a hobby store... partly to get it sooner, but also as no one overseas that even had it, had it any cheaper anyway!
Many overseas places do not even list it at all ! But quite a few places within Australia DID have it ! Weird....

All the video reviews look good... and so do many owners videos.... so it seems it is widely seen as a good glider.
I only know the 'static' aspects of that so far...........
Mar 05, 2019, 02:28 AM
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Ready to Fly... Maiden Flight


The Fox and Dolly were all ready to go, so at 7pm one night it was calm finally so off I went!!
The Dolly worked perfectly, as expected/hoped.....

Watching Gliders fly around is a bit boring.... so the video is just of the Dolly Take-Off portion.
The full video is BIG, but just 17mins. I will see about putting that up on YouTube...

....

Fox 3000mm Glider by FMS - Maiden Flight - Take off portion (1 min 21 sec)
Mar 05, 2019, 02:40 AM
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Flight Report


Seeing it turned very windy right after I landed the Maiden Flight (just as the weather bureau had predicted too! Within 5 minutes accuracy!) it only had that one flight.
I gleaned a number of things about the Fox.....umm, it is heavy!!

Now being heavy is not stopping it flying. Not even stopping it gliding quite well. But not like a 'real' glider would/could.
It really is more of a "Warbird with LONG Wings" !! In how it flies.
Mind you, with Flaps Down - Full Flaps of huge angles - it can then fly along very slow!
So it is more of a "Universal plane" than any single specific master at anything.

I flew it at the stock 90mm CofG and it flew Tail Heavy. But the Pitch Trim was near zero Elevator offset, so that showed it was close to the aims of the design(er). But it might be even better at 85mm.... just a fraction more forwards.

Apart from being heavy, and thus having large Inertias - larger than a Glider should have - it was still fine to fly. It is a Chameleon.... fly a Glider... fly a Sports Plane.... fly a Racer even(!), as it can move fast with its high Power system that it has (though this is a bit of a stretch, as to do so long term things would get a bit hot).
If you really want a GLIDER, this is not it.... but if you want that big MIX of abilities, it is a very good plane for that!
Oh.. and likely to be very good as a Long Range FPV Aircraft too !! Which is a part of my aim,

Another aim is Low Altitude LOS Aerobatics - which could eventuate into Low Altitude FPV Aerobatics.
But it is actually a LITTLE BIT scarey to fly! Due to the high weight. So until I learn what it can and CAN'T do, it will not be safe to push any limits!

Value for money??? Hmmm... not sure. it is very well made.. and has very good features. It is just that the AUD being a poor rate to the USD means ALL foam models cost a lot now!! That makes it hard, or unfair(?), to put a value on them in AUD terms. I think I will say it would be better value if it was AUD$600...... but we don't get that option.
And there is nothing else you could buy instead, nor for less anyway, so...... I will say it is 'fine'. You just have to pay what it costs.....
Mar 24, 2019, 07:38 PM
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Hand Launching the Fox - Pt1


This is a 'heavy' aircraft - even just in pure 'what something weighs' terms. eg Picking up something 5Kg is not like picking up a ball point pen that is insignificant weight to us.
But it is also heavy for 'what it is'.... a model of a Fox Glider, and it is overly heavy for its scale size.

So you have a heavy item you are going to need to "throw"... to get moving so that you bridge the state between not able to fly at all (stationary or very low airspeed) and the state of flying. You can throw and make a ball point 'fly' pretty easily! LOL
This Fox, due to AUW, feels like bridging that gap is going to be somewhat 'hard'......

If you attempt it, without any real information, it could end up in the ground instead of flying! That is the RISK of throwing any aircraft into flight. And the heavier it is, the greater that risk is....
So you need some information. Useful information. Accurate information.
This information could be just how you WATCH someone else throw their Fox and see that it flies.... that is PROOF that it can do so.

A problem with this 'proof' is that it has a wide range of Parameters that all come together to form that RESULT.. that 'proof' that it could be done and then continue to fly onwards fine. eg How much ENERGY did it need to do so fine? How long did it need to be HELD by a human, until released at an AIRSPEED that made it all work fine? Can YOU do the same?
If it was a ball point pen... we all could easily.
Heading to, and over, 5Kg the LIFT available alters outcomes a LOT. More Lift, less human energy needed so it COULD be an easier task.... even an easy task.

Or take an extreme example of Power. If it had 2:1 power to Weigh ratio, you could hold it nose up VERTICAL and it will just rip it out of your hand and go upwards like a ROCKET, without any issues at all !! No need to even FLY at all !
So using high Power can append to... or actually reduce the need.... fly. Instead of needing "100%" flying state, it can have 30% flying state, but a lot of power/Energy - vectored UPWARDS to some angle - to get it moving upwards, not down into the ground!

This Fox has a LOT of power.... I would guesstimate at least 0.8 : 1 thrust to weight, but likely to be more in the 0.9 or higher amount really! it is extremely powerful! This amount of Power can buy you that ability to head UPWARDS, irrespective of lift level. Not totally replace it all, but a lot of it.
But a cost of high Power is, well.... you need to supply igh power.... energy... from your battery. That is easy for this Fox setup to do, but never the less it USES energy to replace a shortfall in Lift. Just for that initial zero airspeed, to flying airspeed, range/period.

Using that high amount of Power has a fair detriment..... the Fox tried to rip itself out of your grip!! It is very strong.
It would be nicer and SAFER if the power level was lower, so that it was more of a match to the motion/speed you throw the Fox at. Except that the 5Kg AUW makes it overly hard for YOU to achieve that required airspeed, so you have to use SOME amount of additional Power, from the Motor/Thrust system.
The key is balance.... viability.... what amount is best and safe to use. The lower, whilst achieving that, is better....

I did tests on the 100% Throttle/Power level, whilst being held, and it is 'insane'! The effort for it to rip it out of your hand is immense. Certainly dangerous - like some monster you are trying to control. So why do that??
Down at the 80% region it is still very strong but far more workable. (And possibly is even at 70% or less)
So I knew right away that you do NOT want to be using 100% Throttle, and that 80% is likely to be plenty(!), thus that is the aim.... to use LESS than 100%!!!

Now..... we have evidence that people throwing the Fix, using 100% Throttle, succeeds....
But has a string of negatives/detriments attached to that too.

And we somewhat 'know'... predict... that 80% will work, BUT not likely to work if you use the SAME PROCESS as those other people are using.
They hold a steep angle.... with the huge Power level..... they throw 'medium hard'.... they use the minimal lift of a plain wing with no Lift Devices helping - like Flaps.
We can derive a different set of workable parameters.... or at least predict them to likely work.....

In most cases I can predict 'workable' things with high accuracy/success, but you still need to TEST... TRY... to verify that.
Mar 24, 2019, 07:56 PM
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Hand Launching the Fox - Pt2


I decided to formulate the 'better' method, but then test its parameters step by step so that there is no danger at any stage that might cause a crash or damage etc.

I set up my Fox TX system (OpenTX) to use the FRsky S8R Auto Level Mode so that I then have an ANGLE Mode of Control available.
A TX channel command value sets an ANGLE of the aircraft, rather than a Rate of Rotation like normal.
If I send "+10" I get +10deg" flight resultant, relative to the ground/Earth.
It is not quite 100% true that this is assured, but EFFECTIVELY it is as good as an assured resultant. But you also do really want to know what factors an make that NOT assured!!

This means I could use TX Command to set a Flight Angle - which I set up on a TX Pot so I could dial up anything from -20deg to +20deg.
Do a quick flight, activate Auto level mode, test some values and verify what give +15deg.... done.
So then I know what value sets the Angle I want.

The reason to use Auto Level is that when you throw the Fox, the Flight Controller will do the BEST possible control job that could be done - versus a human under pressure, or errors etc. The Flight Controller will do it PERFECTLY, at high speed and smooth! This erases any control error/issue off the launch!
It does not mean you must use this forever, after the testing, on any hand launch in future..... though why wouldn't you still anyway!?

The next test was to confirm what Throttle level can fly the Fox 'upwards' at 15deg angle of climb, starting from a very low airspeed. This means fly it along, gliding, to be very slow, then move to that Throttle/power level... 80% whilst also setting the 15deg climb. Verify it works fine, safely, with a bit of leeway to be sure.
So I tested that and it was fine. Even with NO Flaps used. But I also tested Stage1 15deg Flaps, and Full Flaps of 50deg. They all worked perfectly fine. No difference or detriment that could be discerned, and the Flight Controller just achieves it goal of "Climb at 15deg" no matter what. More Lift from Full Flaps is just 'corrected for' because the Flight Controller is going to make sure it climbs at 15deg, at all times, no matter what. Well, as long as it is aerodynamically possible to do so!

So we now KNOW that 80% Throttle is enough to make it climb the 15deg and that the Flight Controller can achieve this for sure, and even for NO Flaps, Stage1 Flaps, or Full Flaps.

Just ONE untested unknown remains..... the transition period from near zero airspeed as it leaves your hand.... to the point it reaches the minimum Airspeed it needs to FLY!

Hmmmmm..... NOTE...... this Airspeed is directly linked to LIFT. The more Lift you have, the LOWER the Airspeed it can FLY at is!!~
And No Flaps needs a HIGHER Airspeed than Stage1 Flaps.... which need a higher Airspeed than FULL Flaps....
Thus it is not a difficult prediction to see the FULL FLAPS will be more optimal than the other two Flap positions!

Oh, a possible negative of Full Flaps is that the more Flap Angle you use, the more DRAG there is. This Drag will SLOW the aircraft down more.
This is actually irrelevant in this case as the POWER level available is so great that Drag is a negligible component anyway. The high Power greatly exceeds any extra Drag of Full Flaps anyway.
Thus..... Full Flaps = MORE LIFT.... and NEGLIGIBLE DRAG = negligible detriment. So of course you would choose to USE them!

The prior Auto Level tests into the 15deg climb had proven all Flap cases worked fine without any having an issue, thus the Full Flaps idea is a certainty to be fine to do.

The next step/test is to THROW the Fox......
Mar 24, 2019, 08:14 PM
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Hand Launching the Fox - Pt3


This first attempt the throw the Fox still has a 'danger' portion.
That period from leaving your hand, until it truly reaches a FLYING Airspeed.
That is an unknown...... and thus potentially dangerous!

To remove this from being a danger I decided that a TWO HANDED throw would totally erase this danger - because it can be thrown very strongly, fast, smooth, accurate.... versus One Handed is much more difficult to do that.
You could get someone else to throw it two handed for you!!

An issue with that is what happens if you are alone???
Or worse, what happens when that other person is a 'useless thrower' that actually launches aircraft more dangerous than your own one handed manner could!!??
So best is do it yourself!!! LOL

For this I set up another TX 'automated sequence'.
A Switch, still gated (enabled/disabled) by the Throttle Cut, but it initiates a 5 second Delay, which then moves on to ramp up the Throttle from 0 to X value over a 3 second period. The Max value of X can be altered using the Throttle TRIM switch. Click that up or down to alter the value - before using it of course(!).

So now I could put the TX on the ground and not need to hold it at all..... because the whole process of Throttling up, and even FLYING the Fox, is done by the TX and the Flight Controller!!

I could flick the "Hand Launch Mode" switch.... pick up the Fox and get ready..... wait as it revs up to "80%" Throttle (76% used actually)..... then throw the Fox TWO handed when I am ready!
To be SAFE the first throw was a STRONG and fast two handed throw!!! And off it flew perfectly fine as hoped/expected really.
No rush to pick up the TX and Switch off the Auto-Throttle Mode, nor the Auto level Mode..... just do those when you want to.

This verifies the SAFETY, as well as the joint Throttle and Auto Climb/Control system.
Next is to throw it WEAKER.... as you don't want to need to use Two Hands or some super strong throw. But you have to work down the scale, to find the lower end SAFELY!

Next throw... two handed but weaker.....
By the second throw I already knew what sort of strength I would only need, and by the third throw that was a known value - quite an easy, but smooth linear 'thrust', did it fine.

Extrapolate that effort/energy amount to what a ONE Handed throw could do.... it was going to be easy!
Next test... do the One Handed throw, but still using the Automated processes.

The key test points are how much does it try to RIP it out of your hand..... and how hard is it to get it moving adequately with one hand/arm of energy....

Those ended up being relatively easy. Though 76% Throttle is sill quite strong and I don't like the effort I need to make sure that is not ripped/dragged out of my one hand. So I will press on testing even lower Throttle % values.
Those tests gave a nice looking 15deg launch angle - not super steep, with mad Power level required. And a Glider that just 'becomes flying' with fair ease from that throwing state.

So 80% Thrust... Full Flaps.... 15deg throw, err FLIGHT, angle..... One Handed.... and very safe....
Mission accomplished!!!

I will probably NOT use my Dolly for take-offs again! Its main "issue" is that you have to go and RETRIEVE it!! But a throw needs nothing further done!!
But the Throw method needs to be assured 100% safe... and that now is. Hmm, maybe only truly 98% I think !!! But even a Dolly launch has some very low % problem cases that COULD occur too. (wheel falls off.... hits a bad bump and skews aside...)
Last edited by PeterVRC; Mar 24, 2019 at 08:20 PM.
Mar 24, 2019, 08:32 PM
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Slope Soaring the Fox


I did some Slope Soaring...... though I think I would call it "Ravine Soaring" really!
Airflows/"Lift" generated by running into and up out of a ravine.....

A few gliders were there and the Fox could not match those others at all.
I could soar "All day"... indefinite. But those others could do so much easier, to much higher, and fly around burning/wasting energy on aerboatics etc, but I had to apply 100% of the efforts to just collecting enough energy to fly around 'sedately'/level.

I would say the "Lift" Levels were "Medium". It was fairly windy.
Any less level of wind and i would not have been able to fly around indefinitely.....
The others surely could have.

It is pretty clear that THIS Fox is "heavy", thus the lesser gliding abilities it has.
But it CAN thermal and/or soar..... it just needs MORE energy from that to do so.

This Ravine area was not anything great, so for sure you could find much better areas to have more energy on hand. But the KEY is that OTHERS did clearly better.
I think I can safely say "This is not a 'good' slope soarer or thermaling glider'. Or, fine if it is quite windy - just not as good as others.
That is fine.... just take it as "This is a VERY strong aerobatic Glider.... that will need Power to do those aerobatics... and it does have Power via a motor, so...."
It is what it is....

My next 'stage' is to add Long Range FPV as that will suit this AIRCRAFT a lot better. Being used as a "Powered Glider"... needing to be that, lol.
I think that it will be extremely well suited to that - plus you get to be "IN IT" also then. So that will be its optimal manner of use/operation.

Plus it LOOKS fantastic, as anyone who SEES it flying along (FPV) will actually see something decent, realistic, true to life (true to full scale), looking! Not some generic drone/FPV looking aircraft.
Last edited by PeterVRC; May 21, 2019 at 09:14 AM.


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