RE: FOX COMPOSITES Bae HAWK, Build thread
 

Hi Dave

What does the present kit cost and include.

Seamus

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Thanks for the info on the decals. I did not have the problem, but it is good info.

I am not sure if the cockpit kit and under wing fairing are included at the moment, perhaps Dave could tell us? I think they may be an optional extra. You do however get wing, fin, tailplane and fuselage bags as standard!

I am lucky and have access to a laser sintering system, which allows me to ‘build’ via ‘additive manufacturing processes’ parts of any shape and form that are drawn on 3D CAD.
The under tailpieces and wing fairings are drawn on Solidworks and created in glass filled nylon.

It is the 1st time this technology has been used in this way and I may be able to supply parts for the Hawk through Dave should the demand be enough.


Trevor has a second set to try out and I await feedback from him.
Paul

RE: FOX COMPOSITES Bae HAWK, Build thread
 

More progress to show at last!

I’ve completed the radio esc/battery installation and these pics show the results.

To let me position the drive batteries entirely in the nose area a few items have gone further aft than normal.

The Rx battery is towards the rear of the wing seat (pic 1)

The Schulze 40/160 (ie 40 nicad cells[=14 lipo]/160A) controller sits on top of the ducting (pic 2) Air scoops on top of the fuselage direct air over it, and the fan also draws air in via the centre fairing moulded into the duct.

A 1/4in liteply battery tray is glued into the nose, slightly raised above the bottom skin to let the Velcro anti-“g” straps slide under it. (pic 3) Self-adhesive Velcro secures the batteries from sliding fore-aft under normal flight loads.

As can be seen in pic 4, I’ve gone 2.4GHz. I really would have liked a JR-12X but for around £900, all you get is a Tx and Rx. Then you need a whole lot more Rx’s to fit out existing planes. For less than half the 12X cost I bought a Spektrum module and 9-chan AR9000 for my PCM-10X, plus two more AR9000s and a couple of extra remote Rx’s and a data logger; and of course I then qualified for the two free AR9000s via the fantastic Horizon-UK offer, which arrived a week after submitting my claim - Whoopee! Pic 4 shows the AR9000 and one remote, and I’ve located a second remote in the fin. I will need more than 9 channels in future models I’m thinking about (even my El Bandito used all ten of my 10X) but getting a few Rx’s bought now will make it easier to save up for just the 12X combo eventually.

Pic 5 shows the data logger.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

I have 12S packs made up of 2x 6S Thunderpower 6600 and 2x 6S Air-Thunder 5000, the latter weighing 1/2lb less than the TPs. So that’s why I made the battery tray long.

Pic 6 shows the TP 6600 located at the rear of the tray, and Pic 7 shows the A-T pack at the front of the tray. Phew! My CG calculations worked and mounting the Stumax fan unit around a foot aft from where the original ICDF unit went paid dividends. Another advantage is the longer intake ducting and shorter exhaust ducts, as explained in Stu's SM110-52 owners manual ( http://www.rcgroups.com/forums/showp...&postcount=647 )

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Pic 8 shows the aileron/flap servo leads and the main gear air line secured in the lg bay. I find it convenient to use self-adhesive and plain Velcro to secure the lines in a bundle to the sides of the gear bays, fuselage etc.

The servo and air lines exit the leading edge root through a small hole. Pic 9. Left and right-hand servo leads are grouped to their own Multiplex green connectors which I’ve colour-coded to ease assembly.

The Robart retract speed control for spring-down retracts only works to slow the gear extending. When “up” is selected the legs really whack up into their wells and if clearance was tight, the wheel collets could punch a hole in the wing upper skin. So I’ve become used to making air line restrictors from 1/16in copper tube, squeezed down to provide the necessary restriction. Pic 10.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Having got the avionic and power installations done I was able to assemble the plane and run the fan up in the garden (pic 10) and take some quick and dirty measurements.

I tethered the plane to our bird feeder pole with a spring balance in the line, and put the plane on my Bobsleigh bungee launch ramp to pre-tension the spring balance, which measures up to 55lb so is not a precision item. On 4kW I measured around 9-9.5lb installed thrust (the graduations on my uncalibrated balance are too close together to be more accurate than that!) which is very satisfactory with 100% FSA inlet and 90mm exhaust, just as advised by Stu in his excellent SM110-52 owners’ manual

The sound from this fan when installed is out of this world. Even having heard the sound of this fan on video, I was still surprised just how smooth and quiet it sounds. I must admit that I’m not a lover of noise, and I’ve always found the usual EDF whine to be a bit embarrassing and un-jet-like. Not this baby!! All EDFs need to sound like this.

The only bad news is that the plane has come out weighing about 1lb more than I’d hoped, at 16lb with the Airthunder 5000s, and 16.5lb with the TP 6600s. Still, with well over 200W/lb at full chat it ain’t going to hang about

Next on the agenda is the cockpit area, and also I must replace a bunch of 4mm connectors with 6mm ones that can handle the current.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

I’ve cracked on with the cockpit. The kit comes with a nice vac-formed cockpit set, the only thing slightly wrong being the shape of the head boxes on the bang seats, though they were correct when Pete Nye designed the original kit way back in the 1980s. The modern head box is shown in the photo here, though for some reason not in the sketch: http://www.martin-baker.com/getdoc/d...2eb8/Mk11.aspx

Pic 11 shows the vac-forms which come with the kit. One sheet has the flap hinge fairings which I’ll fit after first flights. Because I’m painting with cellulose I’ll have to sheath the fairings in glass-epoxy as the paint will flake off the plastic mouldings.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Pic 12 shows the first job which is to trim the canopy frame moulding to accept the cockpit tubs. The frame narrows towards the nose, and the front cockpit tub needs adjusting to fit as seen in pics 13 and 14.

With the tubs inserted in the frame, and the frame on the fuselage with drive batteries installed, I could check how much to remove for battery clearance, shown cross-hatched in pic 15. In fact I removed even more so that there would be plenty of clearance for any size of battery. I removed the entire bottom part of the rear cockpit, and trimmed the front one further up too - pic 16. I glued balsa stiffeners to the rear cockpit followed by a piece of styrene sheet. I was able to use the cockpit floor, trimmed as seen in pic 17, in the front cockpit.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

The seat mouldings are seen in pic 18, marked for cutting. After a fair amount of cutting, mind changing and general frigging about, the results for the seats are seen in pic 19.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

I forgot to photograph the instrument panels and fairings before assembly, but here they are painted and ready to install – pic 20. That job was completed at 12.00 midnight (so don’t look too closely).

RE: FOX COMPOSITES Bae HAWK, Build thread
 

BTW, for those who don't know, the Astra Hawk is an Advanced Stability Training and Research Aircraft (ASTRA) for the Empire Test Pilots' School. Some details of it are here:
http://www.qinetiq.com/ix_etps/schoo...stra_Hawk.html

And no, mine won't have the fancy cockpit setups of the real Astra!

Pics 21,22 & 22a below show that when flown solo the Astra machine is piloted from the rear cockpit, unlike all other Hawks. So my pilot will be a back-seat driver too.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

The pilot came in a bright blue tunic (pic 23 shows the colour inside) with a white helmet. The helmet is a different shape with a different visor from the RAF’s, but thankfully the face was neatly painted already. I did consider re-working the helmet with filler to make it look like the usual RAF one with exposed visor, but then, as with the seat headrests I thought what the heck, just get it painted. Pic 24 shows the result at 1.00am today and overall I’m more satisfied with it than I expected to be.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Pic 25 shows the cockpits painted. The moulded details are not particularly accurate, but you do get a decent impression of a jet cockpit. Pics 26-30 show the completed cockpit; I couldn’t get pix of the HUDs fitted to the Astra machine, so my gunsights represent the old ISIS sights.

Outstanding jobs are wing fences, cockpit glazing, decals, and soldering on all the 6mm connectors when they arrive.

That’s all for the next week or so as my wife Pat and I are setting off on holiday to celebrate our first 40 years of marriage.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Nice job and nice report Gordon. [8D]:D
I look forward to your flying report and meeting up with you this show season.
Between us there should be a few of them about!
Have a nice holiday.

Paul

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Well she's ready. Just finished and newly assembled.

Tomorrow morning I'll re-check the balance and control throws, and if all goes well, tomorrow afternoon will be first flights.

It still needs the dummy flap hinge fairings and the ventral strakes, but I have to get her in the air by Tuesday or she won't get up for a couple of weeks due to other obligations.

Incidentally, the nose light doesn't work. It's a sticky aluminium disc reflecting the camera flash ... hope it does the same in sunlight.

Gordon

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Looks bloody fantastic!

Well done Gorden, look forward to your flight details.

Paul

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Thanks Paul. Ralle's decals really do bring the model to life don't they?

I flew her last night and she goes great. Handles beautifully and with an even better performance than I'd hoped at 16lb auw. Flight report in the next post.

Gordon

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Yippee!! What a great flyer and what a super fan unit. The combination of fan and model couldn't be bettered.

Conditions were perfect for first flights, with a gentle breeze blowing exactly along the runway, and a clear blue sky. It was just after 6:00pm and the sun was getting lower in the sky and I hoped that it wouldn't cause a problem. My flying buddy Ron arrived just as I was finishing assembling the model so we trundled it onto the end of the main runway, lined it up, and left it there while we walked a couple of hundred feet upwind. This was so the plane would be leaving the ground as it reached where we were standing. Wiggling the sticks, I could just make out the tailplane moving.

On opening the throttle wide, the plane began to move ... silently. I couldn't believe it. As it approached us accelerating strongly, a gentle whooshing sound got gradually louder and the plane got bigger. It felt a bit heavy on elevator and I had to pull back on the stick to lift her off just as she swooshed past. What a great sound! As I had 12S on tap rather than the 11S recommended for this fan/motor combo I throttled back a bit in the climb and flipped the retract switch. Banking left away from the sun which was glaring at us from the far end of the runway, the aileron response felt good.

I fed in some up-elevator trim to get her flying level, but aileron and rudder needed no offsets. Even at 16lb weight there was no shortage of climb rate even at about 3/4 throttle, and at a good height I dropped half-flap, to find that the nose did drop a fair bit despite having a spot of up-aileron programmed in with flap. On full flap the nose went down even more so I decided that for the first landing, half-flap would have to do.

Then we noticed that the noseleg hadn't retracted, so I flipped the retract switch and the mains extended OK. After another couple of circuits I brought her in for a fly-by, and followed this with a final circuit and landing. Keeping speed on during the final turn, I only lowered the flaps when established on the glideslope and correcting the nose-down pitch with elevator, brought her in gently though still at a fair speed. The sprung trailing-link main legs that Dick Spreadbury had given me let her land softly and she was down. Even on the landing approach the sound of the fan was gorgeous, whilst taxiing was equally so.

The model handled really well for a first flight, but the sound and power of the Stumax fan made the experience so-o-o-o much better. I don't want to fly any other fan unless it sounds and performs like this one. Yep. I'm deadly serious.

The reason the noseleg hadn't retracted is because I forgot to open the gear doors They are on an over-centre spring, and opened and closed by the noseleg, and I keep 'em shut when the model is stored so that I don't knock them about when handling the model.

We couldn't wait to do the second flight, and take-off was as spectacular as before, both in acceleration and sound. I can't get over that unique scale sound. It really does sound like a quiet turbine. This time the gear retracted properly, and I took her up high to try a stall. On closing the throttle the model took a while to slow down, and then with full up elevator the nose dropped somewhat and the model simply mushed down with no wing drop. Of course you wouldn't want to be doing that on the landing approach as you need to dive her to get speed up again, but the copious washout which is obvious in some photos looks like eradicating any chance of tip-stall.

Before this second flight I'd programmed a spot of up-elevator trim with flap and the nose didn't drop this time when the flaps were lowered. One unexpected thing about lowering flaps was a very loud whistling roaring sound with the flaps deployed. I retracted the flaps and the noise went, extended them again and it came back. Rather unnerving the first few times this happened as I thought that the flaps were about to drop off! In fact the flaps and ailerons are hollow and open at their ends, and when the flaps deploy the open ends are exposed and we suspected that these surfaces then began to behave like organ pipes.I'll have to block the ends up and hope the sound goes away.

I did one loop which was large and powerful (and sounded bee-oootiful too but you could guess that 8) and one slow roll which looked and sounded equally nice. Oh boy! We'd get video on the next flight and PROVE both sound and peformance.

Sadly that was not to be this evening. For this landing I did a proper run-in and break and brought her down fora nice soft landing. On taxiing back however, one of the mains decided to shimmy and the model ground-looped. Silly me had forgotten to file flats on the wire leg stubs and one had loosened, but boy was I lucky that this only happened on taxiing back I didn't have the right size hex key with me, so that ended flying and Ron took some static pics.

The model is on charge as I write, and this morning I'll get the main leg stubs sorted and take her out again.

Many thanks to Stu for producing his superlative and innovative SM110-52 fan unit. And many thanks to Ron for coming and providing much valuable assistance and moral support. I had a great evening!

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Great news Gorden, really glad it has all paid off (told you it was good ;) ).

I look forward to more pics and the video.
I had a great time with mone over the weekend at Bickley, perfomance is stunning on the 44 gold.
I had a lot of interest over the whole weekend, i think Fox Comp have a real winner with this. [8D]
(glad you like the wing!)

Paul

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Paul,
I really like your Hawk. I have been hoping the exchange rate might settle down so I could order one soon, not to mention shipping expense. I would like to put a full set of trailing gear like Gordon has done.
My home field is only 30 feet wide with really nice grass all around and we have a crosswind grass runway that
that would be used a lot too.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Nice job Gordon,

perseverance and experience won the day. I must say you have sorted the problems very well and would be interested in your flight time.
I lost my Hawk due to a radio lockout on its first flight but the Wren 44 was saved. I will build again in the winter but still on the turbine trail.
Bets of luck and well done

David

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Hi Guys

Clubmate Peter Down video'd my Hawk in perfect condtions yesterday evening - many thanks Pete!

The camcorder had a shotgun mike on it so was very much focussed on the model audio-wise. To get the best effect for how the Stumax fan sounds out in the open you need to turn the sound level down well below what's normal for the omni-directional mikes used by most guys, as this thing picked up every little sound made by the model, especially the rattling of the Robart retracts! Use the cameraman's voice level as a guide.

This was only the 4th flight of the model so I still had the timer set to 3.5 minutes. I put 2900mAh back into the batteries on recharge, so I had another minute's flying available with plenty in reserve.

The AirThunder batteries only have 4 or 5 flights on them so haven't "loosened up" yet. I checked the input power with DVM (41V) and Graupner clamp ammeter (90A) at around 3700W. This figure is quite a bit less than the 4.1kw I've seen on testing with my Thunderpower 12s 6600 Extremes, and I still have to fly the model with that pack. The Hawk doesn't need much more power though, I feel ;) The 6600s will guarantee 6-7 minute flights with sensible power and energy management.

Model specs are:
Span/length 59in/59in
Weight 16lb
Wing loading 60oz/sq ft.

I still need to optimise the flap/elevator trim setting. A very enjoyable flight ended with my worst landing to date with this model :eek:

We had two flights yesterday, and this was the second. Now I can start planning a decent aerobatic display schedule as this plane definitely has no shortage of go [8D]

Video is here:

http://rcuvideos.com/item/QM9K48N8MPWWPPN5

Gordon

PS. Better luck with your next Hawk David. The model really is outstanding.

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Nice one Gordon...it sounds like a jet too! By the look of it, it has equal if not more oomph than my Pete Nye one had with an OS.77/Dynamax in it...your loop was huge!

Look fwd to seeing you again soon...maybe park the van up somewhere close, I'll use my guest slot up and we'll have a weekend at Wroughton!

Rgds,

Dick

RE: FOX COMPOSITES Bae HAWK, Build thread
 

That is VERY impressive![sm=thumbs_up.gif]
You have a high AUW but it fly’s really well (good wing).
Most impressed with the large loop, nice![8D]
Landing speed is a bit high, is that you? or not enough AOA? Crow?

Very nice job.[sm=shades_smile.gif]

Paul

RE: FOX COMPOSITES Bae HAWK, Build thread
 

Just love it!! you have to be really proud of that model.. great job