The Gatwick "suspects" (yeah, like Cliff Richard was a "suspect") were well known and well thought of model helicopter enthusiasts. They were hauled in on the "reasonable suspicion" that they had to prove their innocence. That there was immense State pressure put on Sussex Police for some form of result (any result) had nothing whatever to do with it.
The 1km boundary around airports inside which no drone flying is permitted is not enforceable
Current: '03 Strange Rover L322
In trim shop for total refurb: '73 Owen Sedanca 4.2L
Stalled in storage '61 Mark IX with 4.2L
I caught an interview with the chief investigator on the radio. Apparently a national newspaper published the names of the suspects. The investigator was not happy as it caused embarrassment and a large amount of extra work to calm the situation down. I should think the "suspects" are spitting feathers and planning legal action for defamation of character.
The Extra 300S is now covered in shrink film. I need to get some more white and grey trim over the core blue of the air-frame. As soon as that has been done, I`ll post the images. Right now it is Christmas Eve, I`m tired and fancy a brandy before turning in.
This thread still appears popular. Over 12,600 hits now. Good to see so much interest being shown on this aero-modelling subject. Please continue to add your comments and observations.
Happy Christmas everyone. All the best.
Amazing. I put further post here yesterday and despite it still being Boxing Day late afternoon, I see some two hundred people have visited this thread.
Thanks to Richard for his comments on radio gear and other matters.
Christmas Day saw me spend about four hours covering the Extra wing. Today, I cut the quarter inch grey trim strips from the roll and carefully ironed them into place. I can`t say I`m displeased with the result as it matches up nicely with the details already in place on the fuselage. A little more white and grey trim will also be added to the tail plane and fin. The engine cowl and wheel spats now require painting although the exhaust system has not yet arrived and that makes it difficult to know what more needs to be cut away from the cowl at this stage. So the painting will have to wait until the exhaust has been constructed and sent to me. I`m unlikely to see that part for at least the next two weeks. The ailerons await a hinging session and the control rods from the servos to the control horns fabricated. That will probably be done later this evening. The pilot and the canopy also has to be fixed to the model.
The almost mandatory ignition "kill module" arrived from Kingston upon Thames via China.....It always bugs me that sellers can say an item is in UK stock but it eventually arrives from some foreign land. So be it. At least it has arrived. The £6 kill switch is designed to cut the spark ignition to the motor in the event of loss of transmitter signal or loss of receiver reception. A vital piece of equipment to build in. Without the module, in the event of a signal problem, potentially the model if trimmed for straight and level flight, could fly on for miles if a quantity of fuel were still in the tank. The electrical power is from a separate LiFe, two cell, 1100mAh 6.6v battery which feeds to the electronic spark ignition module and provides electrical energy for the engine spark plugs. It also interfaces with the radio receiver but does not power the receiver or the control surface servo units. However, the receiver does send a control signal to the kill switch and the spark ignition module in order to control engine speed and also provide a manual pilot activated method of killing the engine at the end of a flight or in an emergency situation. A red LED signifies that the ignition circuit is live, armed and potentially dangerous when illuminated. An identical Life battery powers the receiver and servos only. It is obviously desirable that one retains full air-frame control even if the spark ignition battery has died.
The precise location of the kill switch, the receiver and also the two LiFe batteries is hard to judge presently without knowing the weight of the still to be constructed silencer/exhaust unit. An aluminum propeller spinner and the propeller itself also influence the Centre of Gravity of the model. I suspect the batteries will need to go well aft in the model but until all parts are to hand, I`m reluctant to start installing batteries and running the cable work. I`ll just have to be patient. Completion of the model is not far off now with perhaps just about three or four days work remaining.
The model initially showed a typical tail down attitude even with the chunky DLE 400cc motor fitted. Bear in mind that the absent and perhaps rather weighty exhaust system is still absent and is likely eventually to weigh a good pound or so. If the exhaust were fitted, that would shift the C of G to a more acceptable forward position. To get the model to balance on the wing main spar, I hung a carrier bag on the propeller and progressively filled it with lumps of lead, large drill bits and a few large nuts until the model balanced to my satisfaction. On the scales and now becoming difficult to handle due to progressively increasing weight, (I`m no longer able to lift the model on an electronic cell due to model length, bulk and weight causing me spinal discomfort) I resorted to grabbing my Fathers analogue bathroom scales. Not the best calibrated unit in the World but good enough to roughly let me see where this model now stands weight wise.
So with both the model and my carrier bag full of metal junk on the scales together, I appear to have a model which is tonight tipping the scales at around 13.5Lbs....certainly the scale needle is not touching the 14Lb/1 Stone mark at this point in time. What this means in practical terms is that the exhaust makers can attempt to produce a super quiet exhaust system for me at a weight of anything up to about 1.5Lbs in weight. I`d not suffer any difficulties even if it were quite heavily constructed. Anything under a finished exhaust weight of that 1.5Lbs means I simply have to add sheet lead to the model to correct the C of G as required. Weight wise, the total figure is acceptable as a flying mass and is still within the CAA agreed legal limit of 15.6Lb/7Kg. Tonight then, I`m pleased. That is one of the two major issues sorted. Just the silencing system and 82Db or less maximum noise limit to achieve once Just Engines get back from their Christmas break and begin the construction. In the meantime, I now know the LiFe battery packs and any other equipment still to be fitted into the fuselage, all need to go as far forward as possible.
On the basis of that, I made up a small micro-ply box in which to house the LiFe batteries and screwed that in place where originally I expected the small electric smoke pump to be located. The smoke pump when it arrives can be located elsewhere. The kill switch for the motor is now in place and a battery isolation switch and illuminating red diode now reside forward of the canopy. A slight issue with the wiring means the power cables from both the spark ignition module and receiver power are slightly in conflict. A bit of help from one of my contacts should resolve this issue. A couple of hours work this morning sees the majority of the servo and ignition module cables neatly installed with three shorter aileron and throttle control cables now being ordered from eBay to finish the installation. Certainly, the electronics on this particular model are quite complex. Pleasingly, servo action is very fast. Running voltage with this 6.6v LiFe set up is higher than previously used on other models.
I`m feeling the expense of this model in my pocket. This build has not come cheaply. Value wise, what is this model worth to me? Probably a thousand pounds once complete. All these parts and materials add up.
The wheel spats have been joined with plastic pipe weld and are setting up. This will be followed by some light polyester car body filler for profiling, then some epoxy and cloth over the joint. Again, these parts are from the dreaded ABS plastic which is difficult to bond successfully and securely. The aluminum landing gear is now in the process of being etch primer painted before receiving coats of sprayed two pack blue top coat. The cowl is about to get fitted and have its mounting holes drilled for screws which will fix it to the model. Not much more I can then do until the exhaust gets made and arrives here. In the meantime, my wallet can take a rest!
The cowl finishing has been problematical but is now coming together. Spraying blue over white went well but removing masking lifted white paint in a couple of areas. Glue from the masking tape left a residue which I eventually removed with white spirit. That left an oily residue which I broke down with Fairy Liquid. Hardly ideal as there is always further oiliness left on the surface. As the white paint two pack aerosol spray had run out, I had to make a decision as to what to do next. The white was wet flatted with P1200 W&D production paper with normal bar soap followed by a good rinse. I found some water based white single pack gloss and applied that by brush. That did go well which was a relief. Red automotive pin striping was applied over the blue and white colour change line and the red detail extended all over the model. Grey an sign writing self adhesive vinyl has been ordered from a local sign writer which will avoid me going a paint route on the last part of the cowl. This image shows a section of the fuselage with full blue, white ,grey and red colour scheme applied. This part of the build has been a pain.
Next on the list was trial weighing with an electronic scale. My Son in Law is about 6ft 7in tall and useful as a sky hook from which to attach the cell. Stood on a chair with as much of the model as I could generate bolted together, a weight of 15lB 8oz was found. Not what I wanted to hear as a silencer still has to be factored into the equation. Technically this model was over weight and still tail heavy....a nightmarish situation and some pretty radical re-working needed. Out came 8oz of electric servos mounted in the tail and re-located nearer the Centre of Gravity position in the fuselage. Out also, came the carbon fibre support tube complete with four servo control wires. That wasn`t fun to do and removal was brutal to say the least. A call to RC Model world sourced four 800m long carbon fibre outer sheath tubes and also small OD tube which would run inside the outer sheaths. 3mm studs will be screwed and glued into the cut to length inner tubes. Mightily expensive they were too. I needed strong and rigid outer tube sheaths to run unsupported down the entire length of the rear fuselage. If needs be, I`ll have to cut in to the covering on the underside of the fuselage to make support fixings if required. That wouldn`t be a nice or easy job. So that is still a problem to be sorted. Various lightening holes have been drilled in the fuselage in an attempt to reduce weight. In addition, one rudder servo has been taken away completely.
The power batteries have been moved well forward above the undercarriage. In addition, the spark ignition module has also gone forward right up to the engine mounting bulkhead. Desperate times indeed. In past years, we had no weight limit. The CAA and the BMFA then brought in the 7KG/15.7Lbs limit for affiliated model clubs. Flying sites now require planning permission which is usually based on that 7Kg weight limit unless a de-restriction has been obtained. In my opinion, this severely and unnecessarily restricts normal sensible flying and building activities. If you get hit by a 7Kg model, it is going to hurt. I probably wouldn`t hurt much more if you were hit by one weighing 8Kg!
There must be a limit, but I really do feel 7Kg is too low and a slightly higher limit would not be to the detriment of anyone. I realize I`m probably a lone voice in this matter, but I can still voice a questioning opinion. Almost all flying sites are well away from any property or gatherings of populous. Potentially, my model becomes "difficult to operate" as soon as it exceeds the 7Kg limit. I believe the idea of the rule to be sound but allowing another Kg to be added would add no additional danger to the situation. It is the spirit of the rule which is important not an unrealistic weight cut off point. To have a useless model because it weighs a few extra ounces is pointless and draconian in my opinion. Whilst I appreciate I am at the upper end of the RC model hobby and therefore likely to run into weight issues, some small amount of flexibility wouldn`t come amiss and have no adverse affect on anyone's safety.
There are de-restricted flying sites but they are few and far between. A 20Kg limit often applies at such places. In practical terms, the 7Kg limit therefore constrains model size in the UK to around a 72" wing span. This model is 80" and is consequentially heavier. Design has changed over the years. This American model was coined about 25 years ago and in the States where issues of weight were not important. Back to the present time and UK flying norms, this model has now become a potentially troubled child. I`ve learned a lot building this model and it remains to be seen whether I can get this model down to an acceptable weight and the noise down to 82Db. A Db meter has been sourced from eBay for about £13. Am I throwing good after bad at this project? I don`t know yet but I`m certainly struggling presently. How much does this model stand me in? Probably about £750 now and my wallet is crying....
So just a brief update here which has helped clear my mind a bit. The carbon fibre and other bits arrive tomorrow. Bye, bye another £100!
This image shows the twin output electronic charger unit topping up the two LiFe 1100mAh two cell batteries for the spark ignition module and the receiver/servo power. That said, one thing is guaranteed. This model is over the normal 7Kg limit and I can see no way of further reducing its mass. There are only so many holes one can cut in the model before structural integrity becomes impaired. The 7Kg limit has not unexpectedly been applied at our flying field just to the western edge of the Biggin Hill airfield flying circuit. Many other model clubs are also bound by the limit which is dictated by the CAA designation of air-space classification. So be it. This Extra can`t and won`t be flown at sites which the 7Kg limit is applied. No arguments, no changes possible. Severe penalties are imposed by the authorities in the event of this legislation being broken and I don`t want to go to prison for infringement. In any case, the Croydon site is small and constricted in flying space. It also sports the massive and un-yielding oak tree to one corner which has a nasty habit of snaring models that make in-correct landing approaches. As a site, it is in many respects unsuitable for this particular model which will require accurate flying skills in a rather confined area. Noise testing and setting up of the model can occur there but it cannot be flown off that airstrip.
The model currently weighs 15.71Lbs/7.4Kg and without the soon to be made muffler being included in the above weight. The finished weight now looks likely to be around 16Lbs. That puts it into the large model category that requires special airspace de-regulation in which to operate. It isn`t the end of the World though. There are many models flying at weights up to and indeed exceeding 20Kg. They just have to be flown at appropriately designated sites and that might require some miles of travel to achieve. One site known to me is north of Grantham at the BMFA flying field. It has a 20Kg limit which would permit this Extra being flown there. But that is 143 miles distant from me. Perhaps good for a long weekend break or similar jaunt.
My old model club near Edenbridge are looking at the possibility of this model being flown at their rather larger site and will be investigating what statutes has been applied. I`m not holding my breath though.
Several of our Croydon members are also members of another local club just to the south of the bottom of the M25. They are allowed to fly heavier models from that site and indeed it is one of the reasons they are members of that particular club in addition to being Croydon members. On the basis of that, I`ve asked to be allowed to join that second club but there presently exists a waiting list and a maximum membership of eighty people. I`ll receive some notification of whether membership is possible once that club know how many people have cancelled their membership for the coming year. Natural wastage occurs in most clubs so one just has to be patient.
In the meantime, although somewhat dispirited and feeling inclined to jump on this model in frustration, I`ll continue to finish this model, get it running with hopefully below 82Db noise levels and see what develops from there. It is not quite the result that I envisaged or hoped for so more fool me for taking on such a large model at the extreme end of UK practicality and usage. As I`ve often said "When you are on the cutting edge of a development project, one occasionally expects disappointment"! Perhaps small wonder then that these large models frequently appear on eBay for pepper corn monies. Broken dreams by the ton and owners perhaps trying to claw back some of their investment! Lets hope I`m not forced to such desperate measures. The model is everything I wished from appearance and build quality so I now have to have the determination to see this project through to a successful conclusion. The word "challenge" doesn`t presently seem to fully describe what I now need to make happen. It is a tough one. The build was easy enough but getting this thing flying through the hoops is quite another. Working on full sized aircraft had far fewer issues!
Beautiful this creation may be...but heck, it is a fair old lump! Mike
As you well know, I have absolutely no experience of model-making. However, it seems that with the vast amount of effort that you've put in to getting the model complete, it must surely be possible to find a weight saving of 1lb somewhere. The restrictions of where you can fly a 16lb model would mean I would do anything to get that weight down to the 7kg limit.
I'm sure there may be good reasons why this won't work but how about:
- shaving a few inches off the ends of the wings
- cutting down the height of the tailplane
- lose the undercarriage and install a couple of lightweight pontoons with sacrificial skidplates
- dump the pilot (autonomous drones are very fashionable!)
There MUST be a way you can do this!
1980 XJ-S Pre-HE
Jaguar 4.2 Supercharged engine (but not with a Jaguar body..)
A mad hacking session removed the four 2oz servos from the tail to a point 27" further towards the Centre of Gravity (towards the front end of the model) which is essentially positioned on the main spar of the wing, ie about 33% of the wing chord (distance from the front leading edge of the wing to the trailing edge). So that helped get rid of some tail heaviness together with moving batteries and spark module forward as well. One servo was removed from the situation altogether saving 2oz in weight. Moving the mass of 8oz of servos meant that less nose weight would eventually be added to get that vital CofG position. It is all about force or mass x distance.That done, I had to transmit the actions of the forward mounted servos back to the rudder and elevators. At huge cost, three rigid, lightweight carbon fibre tube sheaths were installed down the length of the rear fuselage together with tree more smaller carbon tubes to act as push rods running inside those outer sheaths. That of course added two ounces of weight again to the tail but not as much as having those four servos as originally mounted in the tail. Any mods always become weight trade offs.
The net gain of all of that work is that the CofG has been moved forward to a better location, the model is better balanced and the hope is that the again additional weight of the yet to be constructed silencer will make this model balance horizontally level on the CoG position on the main wing spar. Had I not done these actions, I can see I would have had to have added about a half pound of sheet lead to the front end of the model even with the weight of the yet to be received muffler added to the model. The other gain is that after all that work, all be it now with the 4oz fuel tank installed, is that I`ve lightened the model by a whole one ounce. You don`t get something for nothing!!
Whilst building this model, one is always on the look out to reduce structural weight especially in the rear fuselage and tail areas. However in doing so, one finds that "swiss cheesing" whilst weight saving, compromises structural integrity and rigidity and one cannot allow that to happen. So if you drill a load of holes in the structure, you find it all goes floppy and you end up having to glue in other structure into the model to get the strength back. And the glue is heavy as well..... In my experience if your remove six ounces of structure, you end up having to put three ounces of material back in again as reinforcement....It is often a hiding to nothing and one has to think very carefully before chopping out load bearing material.
The kit design weight quoted is between 15-17Lbs. It is an American kit and some of the structure is very robust indeed. The 10mm thick birch ply wing joiner weighed six ounces. That is one load bearing part you would not be swiss cheeseing. You could change the spruce half inch wing spars for smaller balsa sections. By the time you have reinforced those weaker sections you have probably increased weight over and above that of leaving the original spruce spars in place! In other words, you have to leave or create an acceptable amount of structural strength in place. Drop below that minimum and you can expect a guaranteed failure. It is the aero designers biggest nightmare.....getting the compromise right and doing it for one third of the weight that any other damned fool could achieve!!
There remains a small amount of material that I can remove from the centre of the fuselage but not much for the above reasons. Similarly, there is nothing more I`m prepared to remove from the tail end of this model for fear of again weakening structure.
It is not that this model is unduly heavy for its size. It is just that it is a big model and therefore heavy in respect of what the CAA have dictated as the maximum weight of an un-manned flying object within a specific type of controlled airspace in particular selected locations across the UK. Given a flying field located outside a 7Kg max location, then it can be legal as well a flyable. My hope was that I would creep inside the 7Kg weight limit but I haven`t. My problem model and my problem to find a suitable legal flying site somewhere around the bottom southern area of the M25. That is not so easy.
This video and other similar ones give me some encouragement. If you want to see the top players in the RC model world operating their oversized models, this is a good vid to view. Without doubt, these guys are at the top of the league and have my respect for the hours of building undertaken together with professional standard flying abilities achieved over a lifetime of flying model aircraft. This video was taken at one of the large model events held at Cosford where designated air-space allowed the flying of some very large un-manned models. Some of the weights will be well in excess of the higher over 20Kg limits. I suspect some of the models will be flying on a permit granted by the CAA after inspection of the model. This would be similar to full sized, home built, non production aircraft operated under the CAA "Permit to Fly" regulations. Take a look.https://www.google.com/url?sa=t&rct=j&q ... Wrg3lW_28y
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