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Author Topic: P1154 Supersonic Harrier - 70mm EDF  (Read 8543 times)

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Offline Dizz

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P1154 Supersonic Harrier - 70mm EDF
« on: July 27, 2012, 01:44:38 AM »
18 months ago I had thoughts of doing Sea Harrier; I imported a 3-view drawing of a FA2 into ACAD and started my usual routine of scaling the drawing to different sizes, juggling length/span and intake/exhaust/wing areas to find a combination that “worked”.  The trouble is that the wing area is very small in relation to the intake area, so a sensible size fuselage results in a tiny wing.  I then thought about the GR9 with the bigger wing.  Back to ACAD and the areas worked out ok, about April last year I started design proper.  To allow me to try different fan/motor combinations I came up with the idea of using a ply fan adaptor with standard external dimensions (EDF Change Unit) that could drop in through the wing opening – just like the real thing. 

Whilst discussing the Harrier EDF project with my mate and given my tendency to over power my models (particularly thinking of my P1121) he kindly pointed out that the Harrier wasn’t supersonic, which then made me consider the P1154……………. which would have been!

A check in “Project Cancelled” & “British Secret Projects – Jet Fighters since 1950” indicated that there would have been a 100% FAA version.  The P1154 fuselage would be much easier to make basically being  square-ish sided with Phantom-like intakes plus the work I had already done on the EDFCU and wing (with a little artistic licence  - I could always claim it is say it is a later development) would transfer across.  Decision made!

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #1 on: July 27, 2012, 01:50:48 AM »
The first task was to generate a 3D model of the exhaust ducting from the 2D ACAD drawings in Rhino:
The model is saved from Rhino 3D software in a format ready for the next stage of generating tool paths for the CNC router.  There are several parameters that can be adjusted to balance speed of machining against surface finish: you can achieve an excellent finish with a very small step-over, but it takes hours to do.  For example, halving the tool step-over from 1mm to 0.5mm will double the machine time.  The output is another cutter file containing the g-code (which is actually the “numeric” bit of CNC).  The program also has a neat visual output which animates the cutting process.
I used a final step-over of 0.9mm and it still took 2 hours to produce from medium balsa block.  It took another 5 minutes with sand paper to remove the residual tool ridges ready for the vac-former, then the surface was hardened with thin cyano.  Another 5 minutes with fine wire wool resulted in a hard smooth surface. 
 
Pulled 4 formings from the plug.  The only potential issue was the apex of the duct split where the plastic had to stretch a lot and was rather thin. 

Offline Dizz

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #2 on: July 27, 2012, 01:55:19 AM »
I cut out the ducts and slowly trimmed the edges down to achieve a good fit with less than 1mm overlap top to bottom.  I was going to aim for a butt join with strips of scrap plastic overlapping and strengthening the seams attached with MEK, but as the forming is quite thin I was worried that the solvent would simply melt the plastic away to nothing.   I tack glued and pinned some formers inside the duct and used 2 rings on the outside to help jig the 2 halves in place.
The top and bottom glued together with thin cyano wicked along the seams.
I cut the fan end open and removed the formers.  At this point the structure was surprisingly stiff.
This point is where the plastic is thinnest and needed beefing up.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #3 on: July 27, 2012, 01:59:19 AM »
Because the fibre glass P1121 intake duct repair worked so well I decided to use the same technique on this exhaust over the seams.  25g/m glass cloth stuck on with Zap finishing epoxy.

CNC cut 3mm ply parts glued together with a 5mm balsa ring to seat/seal the fan shroud.  I chose dimensions for these parts so that the Wemo mini, HET 6904 and CML 70mm fans will all drop in only requiring some sanding of the balsa rings.  By adjusting the inside face of uprights and sanding the balsa rings this will also take the GC aluminium 70mm fan and a Lander 68mm unit.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #4 on: July 27, 2012, 02:04:59 AM »
I haven’t run up the fan and split exhaust duct together yet.  Really need to do that though to see how much thrust I have lost.  I realised that there may be a problem dropping the fan units into place due to the motor sticking out the back and the fan hub sticking out the front.  More thought required.
To overcome the motor length issue I came up with an extended rear section CNC’ed from ¼” balsa.  I have a standardised the overall length so the different EDFCUs can slot into the same space in the fuselage from the rear (don’t have to worry about fan spinners).  Then the exhaust duct can be attached to the rear of the unit. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #5 on: July 27, 2012, 02:07:00 AM »
Then I got distracted, first by my Viggen, then the P1091 followed by the FD2.  In the New Year  I got back on the case and started on the wing.  I used Profili to generate the ribs, spar dimensions and plans.  To achieve the cranked trailing edge I designed 2 wings with a common tip/root.  Full depth 3mm ply front and rear spars and 1/16 ply ribs.  The Profili results were saved as .dxf files so they can be pasted directly into the master drawing and cutter files produced.  The fin and tailplane structures are the same as previous builds with a 3/32”internal, interlocking balsa frame skinned with 1/16” balsa sheet.  All surfaces build over the plan, wing root ribs jigged to give the characteristic Harrier anhedral angle when joined.

Offline albert0147

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #6 on: July 27, 2012, 02:46:00 AM »
Hello Pete,
Amazing work and thread.  Keep it up.
Take care,
Albert

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Offline Dizz

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #7 on: July 27, 2012, 09:57:05 AM »
Thanks Albert, I'm off to laser cut some alternative fuselage formers so should be able to at least frame-up one side this evening.  I can't go too far though because I have decided to bin the changeable fan idea and have only just ordered the the new one.........more of that later.
All the best
Pete

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #8 on: July 27, 2012, 22:40:39 PM »
Servo mounts built into the outer bays and the wings skinned with 1/16” balsa.  Aileron area cut out on the band saw and ailerons shaped to fit from hard ¼” balsa sheet then hinged with Robart hinge points.

Out rigger pods mix of ¼” and 1/16” laminated balsa – ¼” in the middle with lightening holes.  The edges need rounding off, then they will be glassed before gluing to the wings.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #9 on: July 27, 2012, 22:42:01 PM »
Fuselage outline drawn and formers developed for cutting.  To help with deciding where the various components will sit inside the fuz I use a spreadsheet to estimate moments about the Cof G.  Once I’m happy with the CAD drawings I export as .dxf files to run the cnc router or laser cutter.  This is a complete set of fuselage parts laser cut from balsa and ply.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #10 on: July 28, 2012, 20:03:36 PM »
When I printed the plan I was surprised how large the fuselage was; even bigger than the P1121 which has a 1.7kW power train.  The P1154 was due to get a 70mm/800W fan which obviously wasn’t going to provide enough grunt.  I settled on a metal Lander 78mm fan claiming decent power and thrust figures on 6S and ordered that last weekend.  As the fuselage had already been sized to take the ply fan units there was easily enough room to fit the new fan.  Also, the intakes were big enough to supply the air, so no change needed there.  All I needed to do was change 2 fuselage formers to allow for the increased diameter and I cut them last week - the photo shows the differences.   I have re-drawn the exhaust duct and will make that after the fan is delivered and I can take some measurements.

This morning I made a start on the fuselage.  To provide some stiffness so I can handle the fuselage halves I sheeted the nose and along the keels.  I’ll make and fit the elevator control before joining the 2 halves.
Couldn’t resist seeing what it will look like put  together. 

Offline Dizz

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #11 on: July 29, 2012, 22:52:29 PM »
Heavier duty Flair 3mm elevator joiner with a metal control horn.  Push rod is also 3mm with M3 clevis’ each end.  I made the Aluminium bushes on my lathe this evening (always very satisfying working with metal).  Fuselage sides in the tailplane pivot area have been re-enforced with 1/32” ply doublers. 
Didn’t achieve anything else today because I went flying with Pat and his F22 – second time out for my RBC F35.  All trimming/set-up tweaks have been incorporated now, so next time I’ll start chucking it around a bit more. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #12 on: July 30, 2012, 05:35:41 AM »
Great work!
Mike :af :af
Properly trained, a man can be a dog's best friend

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #13 on: July 30, 2012, 07:36:41 AM »
Cheers Mike.
I'm trying to build this one lighter than my previous efforts,I just hope the fuselage will be strong enough with the minimal formers and lack of longerons/stringers.
Pete

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #14 on: July 30, 2012, 07:37:26 AM »
Here's hoping! A project like this deserves to succeed
Mike
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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #15 on: July 30, 2012, 07:40:18 AM »
Only one way to find out!  :D

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #16 on: July 30, 2012, 21:41:11 PM »
I spent ages this morning pondering how to draw, cnc shape and vac form the intake ducts.  Then the KISS principle kicked in and I realised that I was over-complicating the issue, some 1/64” ply and balsa would do the job in a fraction of the time and effort.   :''
I cut a paper template which was used to cut 2 x 1/64” ply duct outer sides.  After soaking in water the ply became could be bent to a tight radius and inserted into the intake ring.  I left it for a couple of hours to dry before gluing in place.  I wicked thin cyano around the formers to secure the duct in place and roughly trimmed the excess ply. Inside face treated to some sanding sealer, rubbed down then grey primer and rubbed down again to get a nice smooth surface for the air to pass over.  Started with another template for the inside duct faces which were cut from 1/16” balsa.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #17 on: July 31, 2012, 10:25:12 AM »
The balsa had the sanding sealer and grey primer treatment to the inside faces too before gluing in place.  To add some stiffness/strength against the duct collapsing under power I will add some additional 3mm ply bracing to the balsa. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #18 on: August 01, 2012, 04:35:17 AM »
I found some 1/16” hard ¼ grain balsa loafing at home so used that cross-grain on the inside faces instead of ply.
I am worried about fuselage strength behind the fan where the exhaust duct exits the fuselage sides, so yesterday evening I cut another replacement fuselage former and made some doublers.  Rest of the time yesterday was taken up drawing 3D cutter CNC files for a bigger exhaust duct and the canopy which I will be machining this afternoon.  Exhaust duct plug will be routed from an expensive 220x270x55mm laminated block of balsa, 65% of which will be waste material……..results will be worth it though.
 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #19 on: August 01, 2012, 10:16:47 AM »
Ain't hanging about are you mate,coming on a treat another stunner from your stable by the looks of things.
Did you have the "Morning watch" or summat !!
John
Oh yeh,spied a turbine Attacker (I think it was) at Cosford saturday,just got one central wheel under fuse like a Fournier
Now that I am older I thought it was nice I seemed to have more patience,turns out  I don't give  a sh*t

Offline Dizz

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #20 on: August 01, 2012, 12:04:58 PM »
Hi John
Couldn't sleep so was in the workshop pottering along, also on leave so I can do what I like, when I like ;D
Trying to cnc the new exhaust duct plug at the moment, but the machine is playing silly buggers and it is a big lump of balsa to mess-up - I don't have any more block to make a second.  Might leave it and come back tomorrow to finish it.
Will check the write-ups for info on that Attacker, sounds very interesting.  What size was it? LMA show though, so probably big!  Mine is still with MASU getting the main frame crack fixed, hopefully be up for a CTF (with rockets) on Sunday at M'F though.
Take care
Pete

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #21 on: August 01, 2012, 14:17:05 PM »
Hello Dizz,
I have never seen a CNC cutter.  Can you please show some images of it.
Take care,
Albert

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #22 on: August 02, 2012, 01:16:21 AM »
Hi Albert, will get some photos tomorrow.
I was beaten by the computer this morning, will have a second attempt at cutting the exhaust duct plug tomorrow.  When I got home I glued the fuselage halves together with 3 hour epoxy and clamped/jigged square overnight whilst the glue set.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #23 on: August 02, 2012, 23:23:35 PM »
I made the new exhaust duct plug and vac formings today.  Still no sign of the bigger fan.
Back home again I squared off the wing tips then glued on a laser-cut laminated balsa block (1/8” balsa + 1/64” ply core + 3/16” balsa).  These have been sanded to profile and blended into the wing surface.  Any dinks have been filled with light weight filler and sanded flush.  Now ready to glass the top surface tomorrow evening.
Some photos of the CNC router in action cutting the split exhaust tool for Albert.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #24 on: August 03, 2012, 23:22:58 PM »
The fan was delivered today so I have been able to check dimensions, etc to design a mounting method.  With the bigger duct compromising strength in that area I will also have come up with some re-enforcing and a way of keeping the fuz square whilst everything is fitted.  With my previous builds I have had them fully thought through and drawn before starting, but this one is much more “make it up as I go”.  That said, I had another test fit of everything before I start glassing.and I’m actually pretty happy with the way it looks at the moment.   I will need to add the cold nozzles and fairings to complete the picture – hopefully I’ll be able to use them as cooling vents for the ESC. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #25 on: August 07, 2012, 03:04:59 AM »
Before loosing the servo inside the fuz I set up the tailplane linkage over the w/e to give reasonable movement with 100% servo throw on the tx.
Bigger exhaust duct has been vac-formed from 1.2mm styrene sheet.  Seams re-enforced with additional plastic strips stuck on with MEK.  It is much stronger than the 70mm fan version so doesn’t need external bracing.  However it was weak in the same area where the ducts diverge so that region laminated with heavy glass cloth and epoxy.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #26 on: August 07, 2012, 03:09:32 AM »
I have CNC’ed ¼” balsa rings to glue to the fuselage former to support the front of the fan and make the fan/duct adapter.  1.6mm holes at 90 degree spacing which will accept a cocktail stick – this will ensure the column stays straight/square.
A test fit to make sure I can assemble it, will glue it together tomorrow.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #27 on: August 07, 2012, 03:28:07 AM »
Fuselage sheeted with 3/32” and 1/16” med/soft balsa, applying evenly left and right sides to avoid unequal stresses.  Dinks and gaps have been filled.  When set the fuselage will be rubbed down and then glassed before cutting holes for the exhaust.  Have made a start glassing the other bits.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #28 on: August 10, 2012, 12:28:22 PM »
Nose and tail former squared off with a Perma-grit bar and balsa block glued in place which was then carved/sanded to shape.  Wings joined and the top surface has been glassed with one piece of cloth.
Bracing to fit when I cut the openings for the exhaust to jig everything back square.  The duct will become part of the structure idc and I’ll add some extra doublers under the wing seat.  Vac-forming plug for the canopy was too deep for the machine bed so had to be made as a top and bottom.  These 2 parts were glued together with PVA and the whole item was lightly sanded. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #29 on: August 10, 2012, 12:32:26 PM »
Fuselage has been sanded smooth with 240 grit wet and dry paper used dry on a sanding block and glassed up to the intakes with 50g cloth/Zap finishing epoxy . 
This morning I took the leap and cut the fuselage sides for the exhaust.  I have to admit to being rather pleasantly surprised because I thought the fuselage would “flop” apart, but it has remained stiff and the braces/jigs I made are not required.  There is more fettling required to get the fan seated squarely, but it is coming along as I imagined and I'm quite pleased with the overall installation. 
However I do have another worry now concerning thrust lines: we had another go at flying my SR177 at Merryfield on Wednesday and the low exhaust again caused it to violently and uncontrollably pitch up on launch.  The P1154 also has a low thrust line complicated by the interaction with the wing, so I’ll going to add a few degrees of up thrust alignment to the exhaust duct, which should keep the nose down………well that is the theory!  :''
I also have a cunning idea for a take-off dolly, but more of that later.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #30 on: August 12, 2012, 23:09:26 PM »
Made some progress today, but nothing worth a photo. Heavy-weight glass cloth re-enforcing tape was applied over the bottom side wing join.  When the epoxy had cured the bottom surfaces were filled, rubbed down and then glassed.  After some work with my Dremel and a Permagrit tool the exhaust duct now fits and the fan can be fitted.  However, I want some “before” test figures first to see how much is lost when installed.  I managed one run using this test stand before it got too late to be making lots of noise.  I got about 2.2 kg thrust off 1350W=1.64g/W; 0:00, +0:30 and +1:00 figures have gone into my EDF Test spreadsheet.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #31 on: August 13, 2012, 13:21:35 PM »
However I do have another worry now concerning thrust lines: we had another go at flying my SR177 at Merryfield on Wednesday and the low exhaust again caused it to violently and uncontrollably pitch up on launch.  The P1154 also has a low thrust line complicated by the interaction with the wing, so I’ll going to add a few degrees of up thrust alignment to the exhaust duct, which should keep the nose down………well that is the theory!  :''
This is where I struggled to get what you meant but that is because in my head I am thinking ah ha a little downthrust should sort that as I tend to think of what I am doing to to exit of the duct to get the effect. I.E. I want to push the tail up and the nose down so I need down thrust out of the duct the reaction of which is upthrust, so two ways of thinking about the same thing, I will have to watch that one in the future.
« Last Edit: August 13, 2012, 13:32:41 PM by tsr »
Any landing you can walk away from is a good one.
You may need a box of tissues though!

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #32 on: August 13, 2012, 14:21:19 PM »
This is where I struggled to get what you meant but that is because in my head I am thinking ah ha a little downthrust should sort that as I tend to think of what I am doing to to exit of the duct to get the effect. I.E. I want to push the tail up and the nose down so I need down thrust out of the duct the reaction of which is upthrust, so two ways of thinking about the same thing, I will have to watch that one in the future.
Really I suppose I should have referred to a "downward pitching moment" thrust  :''
Did the fan tests this morning, figures attached.
  • Ignore the initial readings because of the initial surge they give and the way they get better once warmed up by passing some decent current
  • Very little difference between High and Auto timing: Lander recommend using High timing, but the ESC is detecting that so might as well leave it in Auto (lines 4 & 5). 
  • Surprisingly the Turnigy packs are no good.  In theory good for 99Amps, but getting nowhere near that figure.  I hope it is because they only have been used a couple of times each and they will improve over the next few cycles (lines 7 & 8). 
  • The Zippy 5000 25C (125A max) and 3000 40C (120A max) packs should have similar performance (other than endurance) and that seems to be the case apart from the 5000 pack holding voltage better by nearly 1 volt, which in turn means more Watts, etc.
  • Altering the frequency to 16kHz reduces power a fraction but the ESC is working far harder and gets several degrees warmer, will use 8kHz installed. 
Conclusions: use the 5000 25C Lipo if I can (otherwise 3000 40C pack), leave ESC pulse timing in Auto and frequency at 8kHz
Now to install the fan in the fuz  :)
« Last Edit: August 13, 2012, 14:54:07 PM by Dizz »

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #33 on: August 14, 2012, 00:23:45 AM »
Looking good mate!  Jeez, you build fast! Mental note - must pull finger on my Hunter!

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #34 on: August 14, 2012, 12:07:34 PM »
Looking good mate!  Jeez, you build fast! Mental note - must pull finger on my Hunter!
Not really, it's only small  :''
Might be up for first flight next week though - am going to try and fly this one before painting, etc in case mod's are required.

The nose/cockpit area has been built up above the canopy edge, filled and glassed.  The fan is in place supported by the balsa rings, but before I go ahead and glue the rear end bits in I’m I have decided to apply a flow coat to the fuselage and prime (easier to do that now rather than work around the exhaust nozzle).

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #35 on: August 15, 2012, 00:33:42 AM »
The fuselage got a coat of epoxy this morning to fill the cloth weave.  This evening I laser cut some supports to act as re-enforcing in the cockpit area ready for when the top keel is removed. 
I also cut out ply splitter plates and balsa supports.   At first I thought they are purely cosmetic, but now I think they might actually help.  I will run a test before and after fitting and compare results.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #36 on: August 15, 2012, 23:17:18 PM »
This thread is exactly what I need. I'm switched on, tuned in baby yeah!
Had you considered a FG fuse formed over styrofoam then released? You ducting looks fantastic and helps to answer a lot of questions.

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Kyosho ME109, Steve Shumate F-14 " " Su37, Blackhorse P-47
Seagul pilatus PC-9, Royal PT-17 Stearman ,GWS A-4, Alex Wittakers Jitterbug

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #37 on: August 16, 2012, 00:36:43 AM »
This thread is exactly what I need. I'm switched on, tuned in baby yeah!
Had you considered a FG fuse formed over styrofoam then released? You ducting looks fantastic and helps to answer a lot of questions.

Subscribed.
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Hi Shane
No, I'm pretty happy with making my fuselages like this, ie sheeting/planking over ply formers.  When it comes to the ducts I'm lucky in that I have access to a 3D CNC router, laser cutter and vac-former, it is still quite a long and involved process though.

I bought some medium (80) Aluminium Oxide paper the other day to try out for rubbing down the flow coat and am pleased to say that it is much better than normal wet and dry – doesn’t clog and seems to stay “sharp” longer.  It took about 30 minutes to prep the fuselage then I gave it a coat of grey primer.  The adapter ring fitted to the fan and exhaust with silicone sealant adhesive.  Exhaust duct glued to the former and fuselage sides with Hysol epoxy.  Fuselage jigged square whilst everything sets.  In the morning I’ll be able to add some doublers around the exhaust opening and give it a test run.

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #38 on: August 16, 2012, 14:09:13 PM »
Slight change of plan – I used bamboo kebab skewers across the top of the opening to act as tie-bars and then did a very quick thrust test.  I got an initial 1400g of thrust but couldn’t run for more than 10 seconds so the battery didn’t have time to warm up.  When I compare with the test stand figures I think I should see about 1700g when I do a proper test later today.   The bamboo rods have done a good job of holding the fuselage level.  To stiffen up in torsion I have added some hard balsa blocks to link the thrust tube to the fuselage former.  Glued in place with Hysol which takes about 5 hours to set so I should be able to complete a full test this evening. 

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Re: P1154 Supersonic Harrier - 70mm EDF
« Reply #39 on: August 16, 2012, 20:46:45 PM »
Top side of the wing has had a flow coat applied, I will do the other side tonight before bed. 
For the installed test I followed the same routine as on the test stand, ie pushing down on the scales, WoT, readings on start, +30 seconds and +1 minute.  Figures are in the attached spreadsheet.  An interesting and disappointing result, but the poor state of the intake lips will not have helped and I need to block off the hole the wires pass through, should be worth a whole 5g of thrust!   :D
Next test (tomorrow) will be with the splitter plates in place. 
« Last Edit: August 16, 2012, 21:07:22 PM by Dizz »

 

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